vendor/ircservices-5.1.24/sockets.c

/* Socket routines.
 *
 * IRC Services is copyright (c) 1996-2009 Andrew Church.
 *     E-mail: <achurch@achurch.org>
 * Parts written by Andrew Kempe and others.
 * This program is free but copyrighted software; see the file GPL.txt for
 * details.
 */

/* Define this to trace function calls: */
/* #define TRACE_CALLS */

/* Define this to log warnings on exceeding buffer size: */
/* #define WARN_ON_BUFSIZE */

/* Define this to disable swritemap().  For IRC Services, we disable this
 * to avoid depending on the presence of munmap(), since we don't use
 * swritemap() anyway. */
#define DISABLE_SWRITEMAP

#include "services.h"
#include <fcntl.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#ifndef DISABLE_SWRITEMAP
# include <sys/mman.h>  /* for munmap() */
#endif

/*************************************************************************/

/* For function call tracing: */

#ifdef TRACE_CALLS

static int trace_depth = -1;

#define ENTER(fmt,...)                                                  \
    trace_depth++;                                                      \
    log_debug(1, "sockets: TRACE: %*s%s(" fmt ")",                      \
              trace_depth*2, "", __FUNCTION__ , ## __VA_ARGS__)
#define ENTER_WITH(retfmt,fmt,...)                                      \
    const char *__retfmt = (retfmt);                                    \
    ENTER(fmt , ## __VA_ARGS__)
#define RETURN do {                                                     \
    log_debug(1, "sockets: TRACE: %*s%s() -> void",                     \
              trace_depth*2, "", __FUNCTION__);                         \
    trace_depth--;                                                      \
    return;                                                             \
} while (0)
#define RETURN_WITH(val) do {                                           \
    typeof(val) __tmp = (val);                                          \
    if (debug) {                                                        \
        char buf[64];                                                   \
        snprintf(buf, sizeof(buf), __retfmt, __tmp);                    \
        log_debug(1, "sockets: TRACE: %*s%s() -> %s",                   \
                  trace_depth*2, "", __FUNCTION__, buf);                \
    }                                                                   \
    trace_depth--;                                                      \
    return __tmp;                                                       \
} while (0)

#else  /* !TRACE_CALLS */

#define ENTER(fmt,...)                  /* nothing */
#define ENTER_WITH(retfmt,fmt,...)      /* nothing */
#define RETURN                          return
#define RETURN_WITH(val)                return(val)

#endif  /* TRACE_CALLS */

/*************************************************************************/

/* Socket data structure */

struct socket_ {
    Socket *next, *prev;
    int fd;                     /* Socket's file descriptor */
    struct sockaddr_in remote;  /* Remote address */
    int flags;                  /* Status flags (SF_*) */

    SocketCallback cb_connect;  /* Connect callback */
    SocketCallback cb_disconn;  /* Disconnect callback */
    SocketCallback cb_accept;   /* Accept callback */
    SocketCallback cb_read;     /* Data-available callback */
    SocketCallback cb_readline; /* Line-available callback */
    SocketCallback cb_trigger;  /* Write trigger callback */

    int write_timeout;          /* Write timeout, in seconds (0 = none) */
    time_t last_write_time;     /* Last time data was successfully sent */

    /* Usage of pointers:
     *    - Xbuf is the buffer base pointer
     *    - Xptr is the address of the next character to store
     *    - Xend is the address of the next character to retrieve
     *    - Xtop is the address of the last byte of the buffer + 1
     * Xend-Xptr (mod Xbufsize) gives the number of bytes in the buffer.
     */
    char *rbuf, *rptr, *rend, *rtop;  /* Read buffer and pointers */
    char *wbuf, *wptr, *wend, *wtop;  /* Write buffer and pointers */

    /* List of mapped memory areas to send, earliest first */
    struct wmapinfo {
        struct wmapinfo *next;
        int32 wait;             /* # of bytes to write from wbuf first */
        const char *map;        /* Start of mapped area, or trigger data */
        int32 maplen;           /* Length of mapped area (0 = write trigger) */
        int32 pos;              /* Current position */
    } *writemap, *writemap_tail;

    uint64 total_read;          /* Total number of bytes read */
    uint64 total_written;       /* Total number of bytes written */
};

#define SF_SELFCREATED  0x0001  /* We created this socket ourselves */
#define SF_BLOCKING     0x0002  /* Writes are blocking */
#define SF_LISTENER     0x0004  /* Socket is a listener socket */
#define SF_CONNECTING   0x0008  /* Socket is busy connecting */
#define SF_CONNECTED    0x0010  /* Socket has connected */
#define SF_MUTE         0x0020  /* Socket is muted */
#define SF_UNMUTED      0x0040  /* Socket was just unmuted */
#define SF_CALLBACK     0x0080  /* Currently calling callbacks */
#define SF_WTRIGGER     0x0100  /* A write trigger has been reached */
#define SF_WARNED       0x0200  /* Warned about hitting buffer limit */
#define SF_DISCONNECT   0x0400  /* Disconnect when writebuf empty */
#define SF_DISCONN_REQ  0x0800  /* Disconnect has been requested */
#define SF_DISCONNECTING 0x1000 /* Socket is in the middle of disconnecting */
#define SF_BROKEN       0x2000  /* Connection was broken while in a callback */
#define SF_DELETEME     0x4000  /* Delete socket when convenient */

/* Used when calling do_disconn() due to SF_DISCONNECT */
#define DISCONN_RESUME_FLAG     0x100
#define DISCONN_LOCAL_RESUME    (void *)((int)DISCONN_LOCAL|DISCONN_RESUME_FLAG)
#define DISCONN_REMOTE_RESUME   (void *)((int)DISCONN_REMOTE|DISCONN_RESUME_FLAG)

/* Size of read/write buffers */
#define read_buffer_size(s)  ((s)->rtop - (s)->rbuf)
#define write_buffer_size(s) ((s)->wtop - (s)->wbuf)

/* Does the socket still have more data that needs to be written? */
#define MORE_TO_WRITE(s)     (write_buffer_len(s) > 0 || ((s)->writemap))

/*************************************************************************/

/* List of all sockets (even unopened ones) */
static Socket *allsockets = NULL;

/* Array of all opened sockets (indexed by FD), dynamically allocated */
static Socket **sockets = NULL;

/* Highest FD number in use plus 1; also length of sockets[] array */
static int max_fd;

/* Set of all connected socket FDs */
static fd_set sock_fds;

/* Set of all FDs that need data written (or are connecting) */
static fd_set write_fds;

/* Total memory used by socket buffers */
static uint32 total_bufsize;

/* Per-connection and total buffer size limits */
static uint32 bufsize_limit = 0, total_bufsize_limit = 0;

/* Global read timeout, in milliseconds */
static int read_timeout = -1;

/*************************************************************************/

/* Internal routine declarations (definitions at bottom of file) */

static int do_callback(Socket *s, SocketCallback cb, void *param);
static void do_accept(Socket *s);
static int fill_read_buffer(Socket *s);
static int flush_write_buffer(Socket *s);
static uint32 resize_how_much(const Socket *s, uint32 current_size, int *errp);
static int resize_rbuf(Socket *s, uint32 size);
static int resize_wbuf(Socket *s, uint32 size);
static int resize_buf(char **p_buf, char **p_ptr, char **p_end, char **p_top,
                      uint32 newsize);
static int reclaim_buffer_space_one(Socket *s);
static int reclaim_buffer_space(void);
static void next_wmap(Socket *s);
static int buffered_write(Socket *s, const char *buf, int len);
static int do_disconn(Socket *s, void *code);
static void sock_closefd(Socket *s);

/*************************************************************************/
/*************************** Global routines *****************************/
/*************************************************************************/

/* Set the per-connection and total buffer size limits (zero means no
 * limit).  Always successful; both values are silently rounded down to a
 * multiple of SOCK_MIN_BUFSIZE (if a value is less than SOCK_MIN_BUFSIZE it
 * is rounded up).  Both values default to zero, i.e. unlimited.
 */

void sock_set_buflimits(uint32 per_conn, uint32 total)
{
    if (per_conn > 0) {
        per_conn = per_conn / SOCK_MIN_BUFSIZE * SOCK_MIN_BUFSIZE;
        if (!per_conn)
            per_conn = SOCK_MIN_BUFSIZE;
    }
    if (total > 0) {
        total = total / SOCK_MIN_BUFSIZE * SOCK_MIN_BUFSIZE;
        if (!total)
            total = SOCK_MIN_BUFSIZE;
    }
    bufsize_limit = per_conn;
    total_bufsize_limit = total;
}

/*************************************************************************/

/* Set the global read timeout.  A value of -1 (default) means no timeout. */

void sock_set_rto(int msec)
{
    read_timeout = msec;
}

/*************************************************************************/

/* Create and return a new socket.  Returns NULL if unsuccessful (i.e. no
 * more space for buffers).
 */

Socket *sock_new(void)
{
    Socket *s;

    ENTER_WITH("%p", "");
    if (total_bufsize_limit) {
        while (total_bufsize + SOCK_MIN_BUFSIZE*2 > total_bufsize_limit) {
            if (!reclaim_buffer_space()) {
                log("sockets: sock_new(): out of buffer space! current=%lu,"
                    " limit=%lu", (unsigned long)total_bufsize,
                    (unsigned long)total_bufsize_limit);
                RETURN_WITH(NULL);
            }
        }
    }

    s = malloc(sizeof(*s));
    if (!s) {
        RETURN_WITH(NULL);
    }
    s->rbuf = malloc(SOCK_MIN_BUFSIZE);
    if (!s->rbuf) {
        int errno_save = errno;
        free(s);
        errno = errno_save;
        RETURN_WITH(NULL);
    }
    s->wbuf = malloc(SOCK_MIN_BUFSIZE);
    if (!s->wbuf) {
        int errno_save = errno;
        free(s->rbuf);
        free(s);
        errno = errno_save;
        RETURN_WITH(NULL);
    }

    s->fd              = -1;
    memset(&s->remote, 0, sizeof(s->remote));
    s->flags           = 0;
    s->cb_connect      = NULL;
    s->cb_disconn      = NULL;
    s->cb_accept       = NULL;
    s->cb_read         = NULL;
    s->cb_readline     = NULL;
    s->cb_trigger      = NULL;
    s->write_timeout   = 0;
    s->last_write_time = time(NULL);
    s->rptr            = s->rbuf;
    s->rend            = s->rbuf;
    s->rtop            = s->rbuf + SOCK_MIN_BUFSIZE;
    s->wptr            = s->wbuf;
    s->wend            = s->wbuf;
    s->wtop            = s->wbuf + SOCK_MIN_BUFSIZE;
    s->writemap        = NULL;
    s->writemap_tail   = NULL;
    s->total_read      = 0;
    s->total_written   = 0;
    LIST_INSERT(s, allsockets);
    total_bufsize += read_buffer_size(s) + write_buffer_size(s);
    RETURN_WITH(s);
}

/*************************************************************************/

/* Free a socket, first disconnecting/closing it if necessary. */

void sock_free(Socket *s)
{
    ENTER("%p", s);
    if (!s) {
        log("sockets: sock_free() with NULL socket!");
        errno = EINVAL;
        RETURN;
    }
    if (s->flags & (SF_CONNECTING | SF_CONNECTED)) {
        s->flags |= SF_DELETEME;
        do_disconn(s, DISCONN_LOCAL);
        /* do_disconn() will call us again at the appropriate time */
        RETURN;
    } else if (s->flags & SF_LISTENER) {
        close_listener(s);
    }
    LIST_REMOVE(s, allsockets);
    total_bufsize -= read_buffer_size(s) + write_buffer_size(s);
    free(s->rbuf);
    free(s->wbuf);
    free(s);
    /* If this was the last socket, free the sockets[] array too */
    if (!allsockets) {
        free(sockets);
        sockets = NULL;
    }
    RETURN;
}

/*************************************************************************/

/* Set a callback on a socket. */

void sock_setcb(Socket *s, SocketCallbackID which, SocketCallback func)
{
    ENTER("%p,%d,%p", s, which, func);
    if (!s) {
        log("sockets: sock_setcb() with NULL socket!");
        errno = EINVAL;
        RETURN;
    }
    switch (which) {
      case SCB_CONNECT:    s->cb_connect  = func; break;
      case SCB_DISCONNECT: s->cb_disconn  = func; break;
      case SCB_ACCEPT:     s->cb_accept   = func; break;
      case SCB_READ:       s->cb_read     = func; break;
      case SCB_READLINE:   s->cb_readline = func; break;
      case SCB_TRIGGER:    s->cb_trigger  = func; break;
      default:
        log("sockets: sock_setcb(): invalid callback ID %d", which);
        break;
    }
    RETURN;
}

/*************************************************************************/

/* Return whether the given socket is currently connected. */

int sock_isconn(const Socket *s)
{
    ENTER_WITH("%d", "%p", s);
    if (!s) {
        log("sockets: sock_isconn() with NULL socket!");
        errno = EINVAL;
        RETURN_WITH(0);
    }
    RETURN_WITH(s->flags & SF_CONNECTED ? 1 : 0);
}

/*************************************************************************/

/* Retrieve address of remote end of socket.  Functions the same way as
 * getpeername() (initialize *lenptr to sizeof(sa), address returned in sa,
 * non-truncated length of address returned in *lenptr).  Returns -1 with
 * errno == EINVAL if a NULL pointer is passed or the given socket is not
 * connected.
 */

int sock_remote(const Socket *s, struct sockaddr *sa, int *lenptr)
{
    ENTER_WITH("%d", "%p,%p,%p", s, sa, lenptr);
    if (!s || !sa || !lenptr || !(s->flags & SF_CONNECTED)) {
        if (!s || !sa || !lenptr) {
            log("sockets: sock_remote() with NULL %s!",
                !s ? "socket" : !sa ? "sockaddr" : "lenptr");
        }
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    if (sizeof(s->remote) <= *lenptr)
        memcpy(sa, &s->remote, sizeof(s->remote));
    else
        memcpy(sa, &s->remote, *lenptr);
    *lenptr = sizeof(s->remote);
    RETURN_WITH(0);
}

/*************************************************************************/

/* Set whether socket writes should block (blocking != 0) or not
 * (blocking == 0).
 */

void sock_set_blocking(Socket *s, int blocking)
{
    ENTER("%p,%d", s, blocking);
    if (!s) {
        log("sockets: sock_set_blocking() with NULL socket!");
        errno = EINVAL;
        RETURN;
    }
    if (blocking)
        s->flags |= SF_BLOCKING;
    else
        s->flags &= ~SF_BLOCKING;
    RETURN;
}

/*************************************************************************/

/* Return whether socket writes are blocking (return value > 0) or not
 * (return value == 0).  Returns -1 if socket is invalid.
 */

int sock_get_blocking(const Socket *s)
{
    ENTER_WITH("%d", "%p", s);
    if (!s) {
        log("sockets: sock_get_blocking() with NULL socket!");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    RETURN_WITH(s->flags & SF_BLOCKING);
}

/*************************************************************************/

/* Set (or clear, if seconds==0) the write timeout for a socket. */

void sock_set_wto(Socket *s, int seconds)
{
    ENTER("%p,%d", s, seconds);
    if (!s || seconds < 0) {
        log("sockets: sock_set_wto() with %s!",
            !s ? "NULL socket" : "negative timeout");
        errno = EINVAL;
        RETURN;
    }
    s->write_timeout = seconds;
    RETURN;
}

/*************************************************************************/

/* Mute a socket.  When a socket is muted, no arriving data will be
 * acknowledged (except to the extent that the operating system
 * automatically acknowledges and buffers the data), and the read and
 * accept callbacks will not be called.  However, a socket in the
 * process of conenction will still call the connect or disconnect
 * callbacks when it completes or fails.
 */

void sock_mute(Socket *s)
{
    ENTER("%p", s);
    if (!s) {
        log("sockets: sock_mute() with NULL socket!");
        RETURN;
    }
    if (!(s->flags & SF_MUTE)) {
        if (s->fd >= 0)
            FD_CLR(s->fd, &sock_fds);
        s->flags |= SF_MUTE;
    }
    RETURN;
}

/*************************************************************************/

/* Unmute a socket.  If any data is waiting, it will be acknowledged and
 * the appropriate callback (read or accept) called during the next call to
 * check_sockets().
 */

void sock_unmute(Socket *s)
{
    ENTER("%p", s);
    if (!s) {
        log("sockets: sock_unmute() with NULL socket!");
        RETURN;
    }
    if (s->flags & SF_MUTE) {
        if (s->fd >= 0)
            FD_SET(s->fd, &sock_fds);
        s->flags &= ~SF_MUTE;
        s->flags |= SF_UNMUTED;
    }
    RETURN;
}

/*************************************************************************/

/* Return amount of data in read buffer.  Assumes socket is valid. */

inline uint32 read_buffer_len(const Socket *s)
{
    if (s->rend >= s->rptr)
        return s->rend - s->rptr;
    else
        return (s->rend + read_buffer_size(s)) - s->rptr;
}


/*************************************************************************/

/* Return amount of data in write buffer.  Assumes socket is valid. */

inline uint32 write_buffer_len(const Socket *s)
{
    if (s->wend >= s->wptr)
        return s->wend - s->wptr;
    else
        return (s->wend + write_buffer_size(s)) - s->wptr;
}

/*************************************************************************/

/* Return total number of bytes received and sent on this socket in
 * *read_ret and *writekb_ret respectively.  Sent data count does not
 * include buffered but unsent data.  Returns 0 on success, -1 on error
 * (invalid socket).
 */

int sock_rwstat(const Socket *s, uint64 *read_ret, uint64 *written_ret)
{
    ENTER_WITH("%u", "%p,%p,%p", s, read_ret, written_ret);
    if (!s) {
        log("sockets: sock_rwstat() with NULL socket!");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    if (read_ret)
        *read_ret = s->total_read;
    if (written_ret)
        *written_ret = s->total_written;
    RETURN_WITH(0);
}

/*************************************************************************/

/* Return the larger of (1) the ratio of the given socket's total buffer
 * size (read and write buffers combined) to bufsize_limit and (2) the
 * ratio of the amount of memory used by all sockets' buffers to
 * total_bufsize_limit, as a percentage rounded up to the next integer.
 * Ratios (1) and (2) are zero if bufsize_limit or total_bufsize_limit,
 * respectively, are set to zero (unlimited).
 *
 * If any of `socksize_ret', `totalsize_ret', `ratio1_ret', and
 * `ratio2_ret' are non-NULL, they are set respectively to the given
 * socket's total buffer size, the amount of memory used by all sockets'
 * buffers, ratio (1) as a percentage, and ratio (2) as a percentage.
 *
 * If `s' is NULL, ratio (1) is set to zero, and *socksize_ret is not
 * modified.
 */

int sock_bufstat(const Socket *s, uint32 *socksize_ret,
                 uint32 *totalsize_ret, int *ratio1_ret, int *ratio2_ret)
{
    int ratio1 = 0, ratio2 = 0;

    ENTER_WITH("%d", "%p,%p,%p,%p,%p", s, socksize_ret, totalsize_ret,
               ratio1_ret, ratio2_ret);
    if (bufsize_limit && s) {
        uint32 size = read_buffer_size(s) + write_buffer_size(s);
        if (bufsize_limit <= 0x7FFFFFFF/100)
            ratio1 = (size*100 + bufsize_limit-1) / bufsize_limit;
        else
            ratio1 = (size + bufsize_limit/100-1) / (bufsize_limit/100);
    }
    if (total_bufsize_limit) {
        if (bufsize_limit <= 0x7FFFFFFF/100)
            ratio2 = (total_bufsize*100 + total_bufsize_limit-1)
                   / total_bufsize_limit;
        else
            ratio2 = (total_bufsize + total_bufsize_limit/100-1)
                   / (total_bufsize_limit/100);
    }
    if (socksize_ret && s)
        *socksize_ret = read_buffer_size(s) + write_buffer_size(s);
    if (totalsize_ret)
        *totalsize_ret = total_bufsize;
    if (ratio1_ret)
        *ratio1_ret = ratio1;
    if (ratio2_ret)
        *ratio2_ret = ratio2;
    if (ratio1 > ratio2)
        RETURN_WITH(ratio1);
    else
        RETURN_WITH(ratio2);
}

/*************************************************************************/
/*************************************************************************/

/* Check all sockets for activity, and call callbacks as necessary.
 * Returns after activity has been detected on at least one socket.
 */

void check_sockets(void)
{
    fd_set rfds, wfds;
    int i;
    int32 res;
    struct timeval tv;
    time_t now = time(NULL);
    Socket *s;

    ENTER("");
    rfds = sock_fds;
    wfds = write_fds;
    if (read_timeout < 0) {
        tv.tv_sec = -1;  // flag: use a NULL tv parameter to select()
        tv.tv_usec = 0;
    } else {
        tv.tv_sec = read_timeout/1000;
        tv.tv_usec = (read_timeout%1000) * 1000;
    }
    for (i = 0; i < max_fd; i++) {
        s = sockets[i];
        if (s && s->write_timeout && MORE_TO_WRITE(s)) {
            int tleft = s->write_timeout - (now - s->last_write_time);
            if (tleft < 0)
                tleft = 0;
            if (tv.tv_sec < 0 || tleft <= tv.tv_sec) {
                tv.tv_sec = tleft;
                tv.tv_usec = 0;
            }
        }
    }
    enable_signals();
    do {
        struct timeval thistv = tv;
        res = select(max_fd, &rfds, &wfds, NULL, tv.tv_sec<0?NULL:&thistv);
    } while (res < 0 && errno == EINTR);
    disable_signals();
    log_debug(3, "sockets: select returned %d", res);
    if (res < 0) {
        log_perror("sockets: select()");
        RETURN;
    }

    for (i = 0; i < max_fd; i++) {
        s = sockets[i];
        if (!s)
            continue;
        if (s->fd != i) {
            log("sockets: BUG: sockets[%d]->fd = %d (should be equal),"
                " clearing socket from table", i, s->fd);
            sockets[i] = NULL;
            continue;
        }

        if (FD_ISSET(i, &wfds)) {
            log_debug(3, "sockets: write ready on fd %d", i);
            if (!s) {
                log("sockets: BUG: got write-ready on fd %d but no socket"
                    " for it!", i);
                continue;
            } else if (s->flags & SF_CONNECTING) {
                /* Connection established (or failed) */
                int val;
                socklen_t vallen;
                vallen = sizeof(val);
                log_debug(2, "sockets: connect on fd %d returned", i);
                if (getsockopt(i, SOL_SOCKET, SO_ERROR, &val, &vallen) < 0) {
                    log_perror("sockets: getsockopt(SO_ERROR) for connect (%d"
                               " -> %s:%u)", i, inet_ntoa(s->remote.sin_addr),
                               htons(s->remote.sin_port));
                    do_disconn(s, DISCONN_CONNFAIL);
                    continue;
                }
                if (val != 0) {
                    errno = val;
                    log_perror("sockets: connect(%d -> %s:%u)", i,
                               inet_ntoa(s->remote.sin_addr),
                               htons(s->remote.sin_port));
                    do_disconn(s, DISCONN_CONNFAIL);
                    continue;
                } else {
                    if (!do_callback(s, s->cb_connect, 0))
                        continue;
                }
                s->flags &= ~SF_CONNECTING;
                s->flags |= SF_CONNECTED;
                FD_CLR(i, &write_fds);
                if (flush_write_buffer(s) < 0)  /* we may have pending data */
                    continue;  /* socket is not valid any more */
                if (!(s->flags & SF_MUTE))
                    FD_SET(i, &sock_fds);
            } else if (!(s->flags & SF_CONNECTED)) {
                log("sockets: BUG: got write-ready on fd %d but socket not"
                    " connected!", i);
            } else {
                if (flush_write_buffer(s) < 0)
                    continue;  /* socket is not valid any more */
            }
        } /* set in write fds */

        while (s->flags & SF_WTRIGGER) {
            /* Write trigger reached */
            void *userdata = (void *)s->writemap->map;
            next_wmap(s);
            s->flags &= ~SF_WTRIGGER;
            do_callback(s, s->cb_trigger, userdata);
        }

        if (FD_ISSET(i, &rfds) || (s && (s->flags & SF_UNMUTED))) {
            log_debug(3, "sockets: %s on fd %d",
                      FD_ISSET(i,&rfds) ? "read ready" : "unmute", i);
            if (!s) {
                log("sockets: BUG: got data on fd %d but no socket for it!",i);
                FD_CLR(i, &sock_fds);
                continue;
            }
            if (s->flags & SF_MUTE) {
                /* Socket was muted by a previous socket's callback */
                log_debug(3, "sockets: socket %d has been muted", i);
                continue;
            }
            s->flags &= ~SF_UNMUTED;
            if (FD_ISSET(i, &rfds)) {
                if (s->flags & SF_LISTENER) {
                    /* Connection arrived */
                    do_accept(s);
                    continue;
                } else if (!(s->flags & SF_CONNECTED)) {
                    log("sockets: BUG: got data on fd %d but not connected!",
                        i);
                    FD_CLR(i, &sock_fds);
                    continue;
                }
                /* Normal read */
                if (read_buffer_len(s) >= read_buffer_size(s)-1) {
                    /* Buffer is full, try to expand it */
                    int newsize = 0;
                    if (read_buffer_size(s) < SOCK_MIN_BUFSIZE)
                        newsize = SOCK_MIN_BUFSIZE;
                    else if (read_buffer_size(s)+SOCK_MIN_BUFSIZE<bufsize_limit)
                        newsize = read_buffer_size(s) + SOCK_MIN_BUFSIZE;
                    if (newsize > 0)
                        resize_rbuf(s, newsize);
                }
                res = fill_read_buffer(s);
                if (res < 0) {
                    /* Connection was closed (or some other error occurred) */
                    if (res < 0)
                        log_perror_debug(1, "sockets: recv(%d)", i);
                    do_disconn(s, DISCONN_REMOTE);
                    continue;
                } else if (res == 0) {
                    /* Read buffer is full (NOTE: this causes busy waiting
                     * until space is made available) */
                }
            } else {
                res = read_buffer_len(s);
            }
            if (res > 0) {
                uint32 left = read_buffer_len(s), newleft;
                if (left == 0) {
                    log("sockets: BUG: 0 bytes avail after successful read!");
                    continue;
                }
                /* Call read callback(s) in a loop until no more data is
                 * left or neither callback takes any data, or the socket is
                 * disconnected */
                newleft = left;
                do {
                    if (!do_callback(s, s->cb_read, (void *)(long)newleft))
                        goto disconnected;
                    if (s->flags & SF_MUTE)
                        break;
                    newleft = read_buffer_len(s);
                    if (s->cb_readline) {
                        char *newline;
                        if (s->rend > s->rptr) {
                            newline = memchr(s->rptr, '\n', newleft);
                        } else {
                            newline = memchr(s->rptr, '\n', s->rtop - s->rptr);
                            if (!newline)
                                newline = memchr(s->rbuf, '\n',
                                                 s->rend - s->rbuf);
                        }
                        if (newline) {
                            if (!do_callback(s, s->cb_readline,
                                             (void *)(long)newleft))
                                goto disconnected;
                            if (s->flags & SF_MUTE)
                                break;
                            newleft = read_buffer_len(s);
                        }
                    }
                } while (newleft != left && (left = newleft) != 0);
                reclaim_buffer_space_one(s);
            }
        } /* socket ready for reading or unmuted */

        if (s->write_timeout
         && MORE_TO_WRITE(s)
         && s->last_write_time + s->write_timeout <= now
        ) {
            if (s->flags & SF_DISCONNECT)
                do_disconn(s, DISCONN_LOCAL_RESUME);
            else
                do_disconn(s, DISCONN_REMOTE);
        }

      disconnected:
        /* at least one statement is required after a label */ ;

    } /* for all sockets */

    RETURN;
} /* check_sockets() */

/*************************************************************************/
/*************************************************************************/

/* Initiate a connection to the given host and port.  If an error occurs,
 * returns -1, else returns 0.  The connection is not necessarily complete
 * even if 0 is returned, and may later fail; use the SCB_CONNECT and
 * SCB_DISCONNECT callbacks.  If this function fails due to inability to
 * resolve a hostname, errno will be set to the negative of h_errno; pass
 * the negative of this value to hstrerror() to get an appropriate error
 * message.
 *
 * lhost/lport specify the local side of the connection.  If they are not
 * given (lhost==NULL, lport==0), then they are left to be set by the OS.
 *
 * If either host or lhost is not a valid IP address and the gethostbyname()
 * function is available, this function may block while the hostname is
 * being resolved.
 *
 * This function may be called from a socket's disconnect callback to
 * establish a new connection using the same socket.  It may not be called,
 * however, if the socket is being freed with sock_free().
 */

int conn(Socket *s, const char *host, int port, const char *lhost, int lport)
{
#if HAVE_GETHOSTBYNAME
    struct hostent *hp;
#endif
    uint8 *addr;
    struct sockaddr_in sa, lsa;
    int fd, i;

    ENTER_WITH("%d", "%p,[%s],%d,[%s],%d", s, host?host:"(null)", port,
               lhost?lhost:"(null)", lport);
    if (!s || !host || port <= 0 || port > 65535) {
        if (port <= 0 || port > 65535)
            log("sockets: conn() with bad port number (%d)!", port);
        else
            log("sockets: conn() with NULL %s!", !s ? "socket" : "hostname");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    if (s->flags & SF_DELETEME) {
        log("sockets: conn() called on a freeing socket (%p)", s);
        errno = EPERM;
        return -1;
    }
    memset(&lsa, 0, sizeof(lsa));
    lsa.sin_family = AF_INET;
    if (lhost) {
        if ((addr = pack_ip(lhost)) != 0)
            memcpy((char *)&lsa.sin_addr, addr, 4);
#if HAVE_GETHOSTBYNAME
        else if ((hp = gethostbyname(lhost)) != NULL)
            memcpy((char *)&lsa.sin_addr, hp->h_addr, hp->h_length);
#endif
        else
            lhost = NULL;
    }
    if (lport)
        lsa.sin_port = htons(lport);

    memset(&sa, 0, sizeof(sa));
    if ((addr = pack_ip(host)) != 0) {
        memcpy((char *)&sa.sin_addr, addr, 4);
        sa.sin_family = AF_INET;
    }
#if HAVE_GETHOSTBYNAME
    else if ((hp = gethostbyname(host)) != NULL) {
        memcpy((char *)&sa.sin_addr, hp->h_addr, hp->h_length);
        sa.sin_family = hp->h_addrtype;
    } else {
        errno = -h_errno;
        RETURN_WITH(-1);
    }
#else
    else {
        log("sockets: conn(): `%s' is not a valid IP address", host);
        errno = EINVAL;
        RETURN_WITH(-1);
    }
#endif
    sa.sin_port = htons((uint16)port);

    if ((fd = socket(sa.sin_family, SOCK_STREAM, 0)) < 0)
        RETURN_WITH(-1);

    if (fcntl(fd, F_SETFL, O_NDELAY) < 0) {
        int errno_save = errno;
        close(fd);
        errno = errno_save;
        RETURN_WITH(-1);
    }

    if ((lhost || lport) && bind(fd,(struct sockaddr *)&lsa,sizeof(sa)) < 0) {
        int errno_save = errno;
        close(fd);
        errno = errno_save;
        RETURN_WITH(-1);
    }

    if ((i = connect(fd, (struct sockaddr *)&sa, sizeof(sa))) < 0
        && errno != EINPROGRESS
    ) {
        int errno_save = errno;
        close(fd);
        errno = errno_save;
        RETURN_WITH(-1);
    }

    if (max_fd < fd+1) {
        int j;
        void *new_sockets = realloc(sockets, (fd+1) * sizeof(*sockets));
        if (!new_sockets) {
            int errno_save = errno;
            close(fd);
            errno = errno_save;
            RETURN_WITH(-1);
        }
        sockets = new_sockets;
        for (j = max_fd; j < fd; j++)
            sockets[j] = NULL;
        max_fd = fd+1;
    }
    sockets[fd] = s;
    s->remote = sa;
    s->fd = fd;
    s->flags &= ~(SF_CONNECTING | SF_CONNECTED);
    if (i == 0) {
        s->flags |= SF_CONNECTED;
        if (!(s->flags & SF_MUTE))
            FD_SET(fd, &sock_fds);
        do_callback(s, s->cb_connect, 0);
    } else {
        s->flags |= SF_CONNECTING;
        FD_SET(fd, &write_fds);
    }
    RETURN_WITH(0);
}

/*************************************************************************/

/* Disconnect a socket.  Returns 0 on success, -1 on error (s == NULL or
 * listener socket).  Calling this routine on an already-disconnected
 * socket returns success without doing anything.  Note that the socket may
 * not be disconnected immediately; callers who intend to reuse the socket
 * MUST wait until the disconnect callback is called before doing so.
 */

int disconn(Socket *s)
{
    ENTER_WITH("%d", "%p", s);
    if (!s) {
        log("sockets: disconn() with NULL socket!");
        errno = EINVAL;
        RETURN_WITH(-1);
    } else if (s->flags & SF_LISTENER) {
        log("sockets: disconn() with listener socket!");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    RETURN_WITH(do_disconn(s, DISCONN_LOCAL));
}

/*************************************************************************/

/* Open a listener socket on the given host and port; returns 0 on success
 * (the socket is set up and listening), -1 on error.  If `host' has
 * multiple addresses, only the first one is used; if `host' is NULL, all
 * addresses are bound to.  As with conn(), a negative errno value
 * indicates a failure to resolve the hostname `host'.  `backlog' is the
 * backlog limit for incoming connections, and is passed directly to the
 * listen() system call.
 *
 * Note that if the SCB_ACCEPT callback is not set, any connections to the
 * socket will be dropped immediately.
 *
 * If host is not a valid IP address and the gethostbyname() function is
 * available, this function may block while the hostname is being resolved.
 */

int open_listener(Socket *s, const char *host, int port, int backlog)
{
#if HAVE_GETHOSTBYNAME
    struct hostent *hp;
#endif
    uint8 *addr;
    struct sockaddr_in sa;
    int fd, i;

    ENTER_WITH("%d", "%p,[%s],%d,%d", s, host?host:"(null)", port, backlog);
    if (!s || port <= 0 || port > 65535 || backlog < 1) {
        if (port <= 0 || port > 65535)
            log("sockets: open_listener() with bad port number (%d)!", port);
        else if (backlog < 1)
            log("sockets: open_listener() with bad backlog (%d)!", backlog);
        else
            log("sockets: open_listener() with NULL socket!");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    memset(&sa, 0, sizeof(sa));
    if (host) {
        if ((addr = pack_ip(host)) != 0) {
            memcpy((char *)&sa.sin_addr, addr, 4);
            sa.sin_family = AF_INET;
        }
#if HAVE_GETHOSTBYNAME
        else if ((hp = gethostbyname(host)) != NULL) {
            memcpy((char *)&sa.sin_addr, hp->h_addr, hp->h_length);
            sa.sin_family = hp->h_addrtype;
        } else {
            errno = -h_errno;
            RETURN_WITH(-1);
        }
#else
        else {
            log("sockets: open_listener(): `%s' is not a valid IP address",
                host);
            errno = EINVAL;
            RETURN_WITH(-1);
        }
#endif
    } else {  /* !host */
        sa.sin_family = AF_INET;
        sa.sin_addr.s_addr = INADDR_ANY;
    }
    sa.sin_port = htons((uint16)port);

    if ((fd = socket(sa.sin_family, SOCK_STREAM, 0)) < 0)
        RETURN_WITH(-1);

    i = 1;
    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i)) < 0) {
        log_perror("sockets: open_listener(): setsockopt(%d, SO_REUSEADDR,"
                   " 1) failed", fd);
    }

    if (fcntl(fd, F_SETFL, O_NDELAY) < 0) {
        int errno_save = errno;
        close(fd);
        errno = errno_save;
        RETURN_WITH(-1);
    }

    if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
        int errno_save = errno;
        close(fd);
        errno = errno_save;
        RETURN_WITH(-1);
    }

    if (listen(fd, backlog) < 0) {
        int errno_save = errno;
        close(fd);
        errno = errno_save;
        RETURN_WITH(-1);
    }

    if (max_fd < fd+1) {
        int j;
        void *new_sockets = realloc(sockets, (fd+1) * sizeof(*sockets));
        if (!new_sockets) {
            int errno_save = errno;
            close(fd);
            errno = errno_save;
            RETURN_WITH(-1);
        }
        sockets = new_sockets;
        for (j = max_fd; j < fd; j++)
            sockets[j] = NULL;
        max_fd = fd+1;
    }
    sockets[fd] = s;
    if (!(s->flags & SF_MUTE))
        FD_SET(fd, &sock_fds);
    s->fd = fd;
    s->flags |= SF_LISTENER;

    /* Listener sockets don't need read/write buffers */
    free(s->rbuf);
    free(s->wbuf);
    s->rbuf = s->rptr = s->rend = s->rtop = NULL;
    s->wbuf = s->wptr = s->wend = s->wtop = NULL;

    RETURN_WITH(0);
}

/*************************************************************************/

/* Close a listener socket. */

int close_listener(Socket *s)
{
    ENTER_WITH("%d", "%p", s);
    if (s == NULL || !(s->flags & SF_LISTENER)) {
        if (s)
            log("sockets: close_listener() with non-listener socket (%d)!",
                s->fd);
        else
            log("sockets: close_listener() with NULL socket!");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    sock_closefd(s);
    s->flags &= ~SF_LISTENER;
    RETURN_WITH(0);
}

/*************************************************************************/

/* Read raw data from a socket, like read().  Returns number of bytes read,
 * or -1 on error.  Only reads from the buffer (does not attempt to fetch
 * more data from the connection).
 */

int32 sread(Socket *s, char *buf, int32 len)
{
    int32 nread = 0;

    ENTER_WITH("%d", "%p,%p,%d", s, buf, len);
    if (!s || !buf || len <= 0) {
        log("sockets: sread() with %s!",
            !s ? "NULL socket" : !buf ? "NULL buffer" : "len <= 0");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    if (s->rend < s->rptr) {
        /* Buffer data wraps around */
        if (s->rptr + len <= s->rtop) {
            /* Only need to read from end of buffer */
            memcpy(buf, s->rptr, len);
            s->rptr += len;
            if (s->rptr >= s->rtop)
                s->rptr -= read_buffer_size(s);
            RETURN_WITH(len);
        } else {
            /* Need to read from both end and beginning */
            nread = s->rtop - s->rptr;
            memcpy(buf, s->rptr, nread);
            s->rptr = s->rbuf;
            len -= nread;
            /* Continue below */
        }
    }
    /* Read data from beginning of buffer */
    if (s->rptr < s->rend) {
        if (len > s->rend - s->rptr)
            len = s->rend - s->rptr;
        memcpy(buf+nread, s->rptr, len);
        s->rptr += len;
        nread += len;
    }
    /* Return number of bytes read */
    RETURN_WITH(nread);
}

/*************************************************************************/

/* Write raw data to a socket, like write().  Returns number of bytes
 * written, or -1 on error.
 */

int32 swrite(Socket *s, const char *buf, int32 len)
{
    ENTER_WITH("%d", "%p,%p,%d", s, buf, len);
    if (!s || !buf || len < 0) {
        log("sockets: swrite() with %s!",
            !s ? "NULL socket" : !buf ? "NULL buffer" : "len < 0");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    RETURN_WITH(buffered_write(s, buf, len));
}

/*************************************************************************/

/* Write data from an mmap()ed area to a socket.  The area will be
 * automatically unmapped when the write completes.
 */

int32 swritemap(Socket *s, const char *buf, int32 len)
{
#ifndef DISABLE_SWRITEMAP
    struct wmapinfo *info;

    ENTER_WITH("%d", "%p,%p,%d", s, buf, len);
    if (!s || !buf || len < 0) {
        log("sockets: swritemap() with %s!",
            !s ? "NULL socket" : !buf ? "NULL buffer" : "len < 0");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    if (!len)
        RETURN_WITH(0);
    info = malloc(sizeof(*info));
    if (!info)
        RETURN_WITH(-1);
    info->next = NULL;
    info->wait = write_buffer_len(s);
    info->map = buf;
    info->maplen = len;
    info->pos = 0;
    if (s->writemap) {
        if (!s->writemap_tail) {
            log("sockets: BUG: socket %d: writemap non-NULL but writemap_tail"
                " NULL", s->fd);
            s->writemap_tail = s->writemap;
            while (s->writemap_tail->next)
                s->writemap_tail = s->writemap_tail->next;
        }
        s->writemap_tail->next = info;
    } else {
        if (s->writemap_tail) {
            log("sockets: BUG: socket %d: writemap NULL but writemap_tail"
                " non-NULL", s->fd);
        }
        s->writemap = info;
    }
    s->writemap_tail = info;
    flush_write_buffer(s);  /* to ensure FD is set in write_fds if needed */
    RETURN_WITH(len);
#else  /* DISABLE_SWRITEMAP */
    errno = ENOSYS;
    RETURN_WITH(-1);
#endif
}

/*************************************************************************/

/* Add a write trigger to the socket.  The `data' parameter will be passed
 * to the callback when the trigger is reached.  Returns 0 on success, -1
 * on failure.
 */

int swrite_trigger(Socket *s, void *data)
{
    struct wmapinfo *info;

    ENTER_WITH("%d", "%p,%p", s, data);
    if (!s) {
        log("sockets: swrite_trigger() with NULL socket!");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    info = malloc(sizeof(*info));
    if (!info)
        RETURN_WITH(-1);
    info->next = NULL;
    info->wait = write_buffer_len(s);
    info->map = (const char *)data;
    info->maplen = 0;
    info->pos = 0;
    if (s->writemap) {
        if (!s->writemap_tail) {
            log("sockets: BUG: socket %d: writemap non-NULL but writemap_tail"
                " NULL", s->fd);
            s->writemap_tail = s->writemap;
            while (s->writemap_tail->next)
                s->writemap_tail = s->writemap_tail->next;
        }
        s->writemap_tail->next = info;
    } else {
        if (s->writemap_tail) {
            log("sockets: BUG: socket %d: writemap NULL but writemap_tail"
                " non-NULL", s->fd);
        }
        s->writemap = info;
    }
    s->writemap_tail = info;
    flush_write_buffer(s);  /* to ensure FD is set in write_fds if needed */
    RETURN_WITH(0);
}

/*************************************************************************/
/*************************************************************************/

/* Read a character from a socket, like fgetc().  Returns EOF if no data
 * is available in the socket buffer.  Assumes the socket is valid.
 */

int sgetc(Socket *s)
{
    int c;

    ENTER_WITH("%d", "%p", s);
    /* No paranoia check here, to save time */
    if (s->rptr == s->rend)
        RETURN_WITH(EOF);
    c = *s->rptr++;
    if (s->rptr >= s->rtop)
        s->rptr -= read_buffer_size(s);
    RETURN_WITH(c);
}

/*************************************************************************/

/* Read a line from a socket, like fgets().  If not enough buffered data
 * is available to fill a complete line, or another error occurs, returns
 * NULL.
 */

char *sgets(char *buf, int32 len, Socket *s)
{
    char *ptr = s->rptr, *eol;
    int32 to_top = s->rtop - ptr;  /* used for efficiency */

    ENTER_WITH("%p", "%p,%d,%p", buf, len, s);
    if (!s || !buf || len <= 0) {
        log("sockets: sgets[2]() with %s!",
            !s ? "NULL socket" : !buf ? "NULL buffer" : "len <= 0");
        RETURN_WITH(NULL);
    }

    /* Find end of line */
    if (s->rend > s->rptr) {
        eol = memchr(s->rptr, '\n', s->rend - s->rptr);
    } else {
        eol = memchr(s->rptr, '\n', to_top);
        if (!eol)
            eol = memchr(s->rbuf, '\n', s->rend - s->rbuf);
    }
    if (!eol)
        RETURN_WITH(NULL);
    eol++;                      /* Point 1 byte after \n */

    /* Set rptr now; old value is in ptr variable */
    s->rptr = eol;
    if (s->rptr >= s->rtop)     /* >rtop is impossible, but just in case */
        s->rptr = s->rbuf;

    /* Note: The greatest possible value for eol is s->rend, so as long as
     * we ensure that rend doesn't wrap around and reach rptr (i.e. always
     * leave at least 1 byte in the buffer unused), we can never have
     * eol == ptr here. */

    /* Trim eol to <len bytes */
    if (eol > ptr) {
        if (eol-ptr >= len)
            eol = ptr + len-1;
    } else {
        if (to_top >= len-1)  /* we don't mind eol == rtop */
            eol = ptr + len-1;
        else if (to_top + (eol - s->rbuf) >= len)
            eol = s->rbuf + (len-1 - to_top);
    }

    /* Actually copy to buffer and return */
    if (eol > ptr) {
        memcpy(buf, ptr, eol-ptr);
        buf[eol-ptr] = 0;
    } else {
        memcpy(buf, ptr, to_top);
        memcpy(buf+to_top, s->rbuf, eol - s->rbuf);
        buf[to_top + (eol - s->rbuf)] = 0;
    }
    RETURN_WITH(buf);
}

/*************************************************************************/

/* Reads a line of text from a socket, and strips newline and carriage
 * return characters from the end of the line.
 */

char *sgets2(char *buf, int32 len, Socket *s)
{
    char *str;

    ENTER_WITH("%p", "%p,%d,%p", buf, len, s);
    str = sgets(buf, len, s);
    if (!str)
        RETURN_WITH(str);
    str = buf + strlen(buf)-1;
    if (*str == '\n')
        *str-- = 0;
    if (*str == '\r')
        *str = 0;
    RETURN_WITH(buf);
}

/*************************************************************************/

/* Write a string to a socket, like fputs().  Returns the number of bytes
 * written.
 */

int sputs(const char *str, Socket *s)
{
    ENTER_WITH("%d", "[%s],%p", str?str:"(null)", s);
    if (!str || !s) {
        log("sockets: sputs() with %s!",
            !s ? "NULL socket" : "NULL string");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    RETURN_WITH(buffered_write(s, str, strlen(str)));
}

/*************************************************************************/

/* Write to a socket a la [v]printf().  Returns the number of bytes written;
 * in no case will more than 65535 bytes be written (if the output would be
 * be longer than this, it will be truncated).
 */

int sockprintf(Socket *s, const char *fmt, ...)
{
    va_list args;
    int ret;

    ENTER_WITH("%d", "%p,[%s],...", s, fmt?fmt:"(null)");
    va_start(args, fmt);
    ret = vsockprintf(s, fmt, args);
    va_end(args);
    RETURN_WITH(ret);
}

int vsockprintf(Socket *s, const char *fmt, va_list args)
{
    char buf[65536];

    ENTER_WITH("%d", "%p,[%s],%p", s, fmt?fmt:"(null)", args);
    if (!s || !fmt) {
        log("sockets: [v]sockprintf() with %s!",
            !s ? "NULL socket" : "NULL format string");
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    RETURN_WITH(buffered_write(s, buf, vsnprintf(buf,sizeof(buf),fmt,args)));
}

/*************************************************************************/
/************************** Internal routines ****************************/
/*************************************************************************/

/* Call a callback on the given socket.  Handles setting and clearing
 * SF_CALLBACK, and checking for remote disconnects after the callback
 * completes.  Returns 0 if the socket has been disconnected, 1 otherwise.
 * If 0 is returned, the socket should be considered no longer valid; if it
 * was an automatically-created socket, the socket itself will have been
 * freed.
 *
 * `s' or `cb' may be NULL, in which case this routine does nothing and
 * returns 1.
 */

static int do_callback(Socket *s, SocketCallback cb, void *param)
{
    ENTER_WITH("%d", "%p,%p,%p", s, cb, param);
    if (s && cb) {
        /* Check whether the SF_CALLBACK flag was set; if it is, then this
         * is a nested callback, so don't clear the flag or disconnect the
         * socket afterwards. */
        int was_set = s->flags & SF_CALLBACK;

        if (!was_set)
            s->flags |= SF_CALLBACK;
        log_debug(3, "sockets: callback(%d,%p,%p)", s->fd, cb, param);
        cb(s, param);
        log_debug(3, "sockets: ...cbret(%d,%p,%p)", s->fd, cb, param);
        if (!was_set) {
            s->flags &= ~SF_CALLBACK;
            if (s->flags & SF_BROKEN) {
                log_debug(3, "sockets: ...broken");
                do_disconn(s, DISCONN_REMOTE_RESUME);
                RETURN_WITH(0);
            }
            if (s->flags & SF_DELETEME) {
                log_debug(3, "sockets: ...deleteme");
                sock_free(s);
                RETURN_WITH(0);
            }
            if ((s->flags & SF_DISCONNECT) || s->fd < 0) {
                log_debug(3, "sockets: ...disconnect");
                RETURN_WITH(0);
            }
            log_debug(3, "sockets: ...normalret");
        } else {  /* SF_CALLBACK was already set */
            log_debug(3, "sockets: ...nestedret");
        }
    }
    RETURN_WITH(1);
}

/*************************************************************************/

/* Accept a connection on the given socket.  Called from check_sockets(). */

static void do_accept(Socket *s)
{
    int i;
    struct sockaddr_in sin;
    socklen_t sin_len = sizeof(sin);
    int newfd;

    ENTER("%p", s);
    newfd = accept(s->fd, (struct sockaddr *)&sin, &sin_len);
    if (newfd < 0) {
        if (errno != ECONNRESET)
            log_perror("sockets: accept(%d)", s->fd);
    } else if (!s->cb_accept) {
        /* No accept callback, so just throw the connection away */
        close(newfd);
    } else if (fcntl(newfd, F_SETFL, O_NDELAY) < 0) {
        log_perror("sockets: fcntl(NDELAY) on accept(%d)", s->fd);
        close(newfd);
    } else {
        Socket *news = sock_new();
        if (!news) {
            log("sockets: accept(%d): Unable to create socket structure"
                " (out of buffer space?)", s->fd);
        } else {
            news->fd = newfd;
            news->flags |= SF_SELFCREATED | SF_CONNECTED;
            memcpy(&news->remote, &sin, sin_len);
            for (i = newfd; i < max_fd; i++);
            if (max_fd < newfd+1) {
                void *new_sockets =
                               realloc(sockets, (newfd+1) * sizeof(*sockets));
                if (!new_sockets) {
                    sock_free(news);
                    close(newfd);
                    RETURN;
                }
                sockets = new_sockets;
                for (i = max_fd; i < newfd; i++)
                    sockets[i] = NULL;
                max_fd = newfd+1;
            }
            sockets[newfd] = news;
            if (!(news->flags & SF_MUTE))
                FD_SET(newfd, &sock_fds);
            do_callback(s, s->cb_accept, news);
        }
    }
    RETURN;
}

/*************************************************************************/

/* Fill up the read buffer of a socket with any data that may have arrived.
 * Returns the number of bytes read (nonzero), or -1 on error; errno is set
 * by recv() calls but is otherwise preserved.
 */

static int fill_read_buffer(Socket *s)
{
    int nread = 0;
    int errno_save = errno;

    ENTER_WITH("%d", "%p", s);
    if (s->fd < 0) {
        errno = EBADF;
        RETURN_WITH(-1);
    }
    for (;;) {
        int maxread, res;
        if (read_buffer_len(s) >= read_buffer_size(s)-1) {
            /* Read buffer is full; try to expand the buffer. */
            int over;
            int32 more = resize_how_much(s, read_buffer_size(s), &over);
            if (more) {
                if (!resize_rbuf(s, read_buffer_size(s) + more)) {
                    log("sockets: attempt to expand socket %d read buffer"
                        " failed (out of memory?)", s->fd);
                    errno_save = EAGAIN;
                    if (nread == 0)
                        nread = -1;
                    break;
                }
            } else {
#ifdef WARN_ON_BUFSIZE
                if (!(s->flags & SF_WARNED)) {
                    log("sockets: socket %d exceeded %s buffer size limit"
                        " (%d)", s->fd, over ? "per-connection" : "total",
                        over ? bufsize_limit : total_bufsize_limit);
                    s->flags |= SF_WARNED;
                }
#endif
                errno_save = EAGAIN;
                if (nread == 0)
                    nread = -1;
                break;
            }
        }
        if (s->rend < s->rptr)  /* wrapped around? */
            maxread = (s->rptr-1) - s->rend;
        else if (s->rptr == s->rbuf)
            maxread = s->rtop - s->rend - 1;
        else
            maxread = s->rtop - s->rend;
        do {
            errno = 0;
            res = recv(s->fd, s->rend, maxread, 0);
            if (res <= 0 && errno == 0)
                errno = ECONNRESET;  /* make a guess */
        } while (res <= 0 && errno == EINTR);
        errno_save = errno;
        log_debug(3, "sockets: fill_read_buffer wanted %d, got %d",
                  maxread, nread);
        if (res <= 0) {
            if (nread == 0)
                nread = -1;
            break;
        }
        nread += res;
        s->total_read += res;
        s->rend += res;
        if (s->rend == s->rtop)
            s->rend = s->rbuf;
    }
    if (nread == 0) {
        nread = -1;
        errno = ENOBUFS;
    } else {
        errno = errno_save;
    }
    RETURN_WITH(nread);
}

/*************************************************************************/

/* Try and write up to one chunk of data from the buffer to the socket.
 * Return -1 on error, -2 if a socket waiting for disconnection was closed,
 * or else how many bytes were written.  (Note that a return value of zero
 * should not be considered an error.)
 */

static int flush_write_buffer(Socket *s)
{
    int32 maxwrite, nwritten;

    ENTER_WITH("%d", "%p", s);
    if (s->fd < 0) {
        errno = EBADF;
        RETURN_WITH(-1);
    }
    if (!sock_isconn(s))  /* not yet connected */
        RETURN_WITH(0);
    if (s->flags & SF_WTRIGGER) {
        /* Write trigger is still pending on this socket, don't do anything */
        nwritten = 0;
        goto check_result;
    }
    /* "while" instead of "if" to handle the case of:
     *     s->writemap->wait == 0
     *     s->writemap->pos == s->writemap->maplen (should be impossible here)
     *     s->writemap->next->wait == 0
     */
    while (s->writemap && s->writemap->wait <= 0) {
        /* Write data from the map instead of the buffer */
        if (!s->writemap->maplen) {
            /* It's a trigger, stop here.  We don't skip to the next wmap
             * yet in case we're called again before the trigger callback
             * is called. */
            s->flags |= SF_WTRIGGER;
            nwritten = 0;  /* return value */
            goto check_result;
        }
        maxwrite = s->writemap->maplen - s->writemap->pos;
        if (maxwrite > 0) {
            nwritten = send(s->fd, s->writemap->map + s->writemap->pos,
                            maxwrite, 0);
            log_debug(3, "sockets: flush_write_buffer/map wanted %d, got %d",
                      maxwrite, nwritten);
            if (nwritten > 0) {
                s->writemap->pos += nwritten;
                if (s->writemap->pos >= s->writemap->maplen)
                    next_wmap(s);
            }
            goto check_result;
        } else {
            next_wmap(s);
        }
    }
    nwritten = 0;
    if (s->wend != s->wptr) {
        if (s->wptr > s->wend)  /* wrapped around? */
            maxwrite = s->wtop - s->wptr;
        else
            maxwrite = s->wend - s->wptr;
        if (s->writemap && maxwrite > s->writemap->wait) {
            maxwrite = s->writemap->wait;
            if (maxwrite <= 0) {
                /* paranoia: this is impossible from the while() above */
                log("sockets: BUG: flush_write_buffer(%d): writemap wait 0"
                    " after while", s->fd);
                do_disconn(s, DISCONN_REMOTE);
                RETURN_WITH(-1);
            }
        }
        nwritten = send(s->fd, s->wptr, maxwrite, 0);
        log_debug(3, "sockets: flush_write_buffer wanted %d, got %d",
                  maxwrite, nwritten);
        if (nwritten > 0) {
            struct wmapinfo *info;
            for (info = s->writemap; info; info = info->next) {
                info->wait -= nwritten;
            }
            s->wptr += nwritten;
            if (s->wptr >= s->wtop)
                s->wptr = s->wbuf;
        }
      check_result:
        if (nwritten < 0 && errno != EAGAIN && errno != EINTR) {
            int errno_save = errno;
            if (errno != ECONNRESET && errno != EPIPE)
                log_perror("sockets: flush_write_buffer(%d)", s->fd);
            do_disconn(s, DISCONN_REMOTE);
            errno = errno_save;
            RETURN_WITH(-1);
        }
        if (nwritten > 0) {
            s->last_write_time = time(NULL);
            s->flags &= ~SF_WARNED;
            s->total_written += nwritten;
        } else {
            nwritten = 0;  /* return value */
        }
    }
    if ((s->flags & SF_CALLBACK) || MORE_TO_WRITE(s)) {
        FD_SET(s->fd, &write_fds);
    } else {
        FD_CLR(s->fd, &write_fds);
        if (s->flags & SF_DISCONNECT) {
            s->flags &= ~SF_DISCONNECT;
            do_disconn(s, DISCONN_LOCAL_RESUME);
            RETURN_WITH(-2);
        } else {
            reclaim_buffer_space_one(s);
        }
    }
    RETURN_WITH(nwritten);
}

/*************************************************************************/

/* Return the amount by which a socket's read or write buffer should be
 * expanded.  Return zero if the per-connection or total network buffer
 * size limits have been reached and the buffer cannot be expanded; in
 * this case, set *errp to 1 if the per-connection buffer size limit was
 * exceeded, 0 if the total buffer size limit was exceeded.
 */

static uint32 resize_how_much(const Socket *s, uint32 current_size, int *errp)
{
    uint32 socktotal = read_buffer_size(s) + write_buffer_size(s);
    int32 more;
    int over = 0, over_total = 0;

    /* Check current size against limits */
    if (bufsize_limit && socktotal >= bufsize_limit)
        over = 1;
    if (total_bufsize_limit && total_bufsize >= total_bufsize_limit)
        over_total = 1;
    if (over || over_total) {
        if (over)
            *errp = 1;
        else
            *errp = 0;
        return 0;
    }

    /* Expand by 10%, rounded up to a multiple of SOCK_MIN_BUFSIZE */
    more = current_size / 10;
    more = (more+SOCK_MIN_BUFSIZE-1) / SOCK_MIN_BUFSIZE * SOCK_MIN_BUFSIZE;

    /* Make sure new size doesn't exceed limits */
    if (bufsize_limit && socktotal + more >= bufsize_limit)
        more = bufsize_limit - socktotal;
    if (total_bufsize_limit && total_bufsize + more >= total_bufsize_limit)
        more = total_bufsize_limit - total_bufsize;
    if (more < 0) {
        more = 0;
        /* This shouldn't be possible; assume it's the total buffer size */
        *errp = 0;
    }

    /* Return it */
    return more;
}


/* Resize a socket's read or write buffer. */

static int resize_rbuf(Socket *s, uint32 size)
{
    ENTER("%p,%u", s, size);
    if (size <= read_buffer_len(s)) {
        log("sockets: BUG: resize_rbuf(%d): size (%d) <= rlen (%d)"
            " (cursize %ld)", s->fd, size, read_buffer_len(s),
            (long)(s->rtop - s->rbuf));
        RETURN_WITH(0);
    }
    RETURN_WITH(resize_buf(&s->rbuf, &s->rptr, &s->rend, &s->rtop, size));
}


static int resize_wbuf(Socket *s, uint32 size)
{
    ENTER("%p,%u", s, size);
    if (size <= write_buffer_len(s)) {
        log("sockets: BUG: resize_wbuf(%d): size (%d) <= wlen (%d)"
            " (cursize %ld)", s->fd, size, write_buffer_len(s),
            (long)(s->wtop - s->wbuf));
        RETURN_WITH(0);
    }
    RETURN_WITH(resize_buf(&s->wbuf, &s->wptr, &s->wend, &s->wtop, size));
}

/* Routine that does the actual resizing.  Assumes that newsize >= current
 * size.  Returns nonzero on success, zero on failure (out of memory). */
static int resize_buf(char **p_buf, char **p_ptr, char **p_end, char **p_top,
                       uint32 newsize)
{
    uint32 size = *p_top - *p_buf;
    char *newbuf;
    uint32 len = 0;

    ENTER_WITH("%d", "%p,%p,%p,%p,%u", p_buf, p_ptr, p_end, p_top, newsize);
    if (newsize <= size)
        RETURN_WITH(1);
    newbuf = malloc(newsize);
    if (!newbuf)
        RETURN_WITH(0);
    total_bufsize -= size;
    total_bufsize += newsize;
    /* Copy old data to new buffer, if any */
    if (*p_end < *p_ptr) {
        len = *p_top - *p_ptr;
        memcpy(newbuf, *p_ptr, len);
        *p_ptr = *p_buf;
    }
    if (*p_end > *p_ptr) {
        memcpy(newbuf+len, *p_ptr, *p_end - *p_ptr);
        len += *p_end - *p_ptr;
    }
    free(*p_buf);
    *p_buf = newbuf;
    *p_ptr = newbuf;
    *p_end = newbuf + len;
    *p_top = newbuf + newsize;
    RETURN_WITH(1);
}

/*************************************************************************/

/* Try to reclaim unused buffer space.  Return 1 if some buffer space was
 * freed, 0 if not.
 */

static int reclaim_buffer_space_one(Socket *s)
{
    uint32 rlen = read_buffer_len(s), wlen = write_buffer_len(s);
    int retval = 0;

    ENTER_WITH("%d", "%p", s);
    if (read_buffer_size(s) > SOCK_MIN_BUFSIZE
     && rlen < read_buffer_size(s) - SOCK_MIN_BUFSIZE
    ) {
        if (rlen < SOCK_MIN_BUFSIZE) {
            rlen = SOCK_MIN_BUFSIZE;
        } else {
            /* Round up to the next multiple of SOCK_MIN_BUFSIZE, leaving
             * at least one byte available */
            rlen += SOCK_MIN_BUFSIZE;
            rlen /= SOCK_MIN_BUFSIZE;
            rlen *= SOCK_MIN_BUFSIZE;
        }
        resize_rbuf(s, rlen);
        retval = 1;
    }
    if (write_buffer_size(s) > SOCK_MIN_BUFSIZE
     && wlen < write_buffer_size(s) - SOCK_MIN_BUFSIZE
    ) {
        if (wlen < SOCK_MIN_BUFSIZE) {
            wlen = SOCK_MIN_BUFSIZE;
        } else {
            wlen += SOCK_MIN_BUFSIZE;
            wlen /= SOCK_MIN_BUFSIZE;
            wlen *= SOCK_MIN_BUFSIZE;
        }
        resize_wbuf(s, wlen);
        retval = 1;
    }
    RETURN_WITH(retval);
}


static int reclaim_buffer_space(void)
{
    Socket *s;
    int retval = 0;

    ENTER_WITH("%d", "");
    LIST_FOREACH (s, allsockets) {
        retval |= reclaim_buffer_space_one(s);
    }
    RETURN_WITH(retval);
}

/*************************************************************************/

/* Free the first map on the socket's writemap list. */

static void next_wmap(Socket *s)
{
    struct wmapinfo *next;

    ENTER("%p", s);
    if (!s || !s->writemap) {
        log("sockets: BUG: next_wmap() with NULL %s!",
            s ? "writemap" : "socket");
        RETURN;
    }
    if (s->writemap->map) {
#ifdef DISABLE_SWRITEMAP
        log("sockets: BUG: DISABLE_SWRITEMAP but non-NULL map %p for socket"
            " %p", s->writemap->map, s);
#else
        munmap((void *)s->writemap->map, s->writemap->maplen);
#endif
    }
    next = s->writemap->next;
    free(s->writemap);
    if (next) {
        s->writemap = next;
    } else {
        s->writemap = s->writemap_tail = NULL;
    }
    RETURN;
}

/*************************************************************************/

/* Write data to a socket with buffering. */

static int buffered_write(Socket *s, const char *buf, int len)
{
    int nwritten, left = len;
    int errno_save = errno;

    ENTER_WITH("%d", "%p,%p,%d", s, buf, len);
    if (s->fd < 0) {
        errno = EBADF;
        RETURN_WITH(-1);
    }

    /* Reset the write timeout if the buffer is currently empty and we're
     * not busy writing a mapped buffer. */
    if (!MORE_TO_WRITE(s))
        s->last_write_time = time(NULL);

    while (left > 0) {

        /* Fill up to the current buffer size. */
        if (write_buffer_len(s) < write_buffer_size(s)-1) {
            int maxwrite;
            /* If buffer is empty, reset pointers to beginning for efficiency*/
            if (write_buffer_len(s) == 0)
                s->wptr = s->wend = s->wbuf;
            if (s->wptr == s->wbuf) {
                /* Buffer not wrapped */
                maxwrite = s->wtop - s->wend - 1;
            } else {
                /* Buffer is wrapped.  If this write would reach to or past
                 * the end of the buffer, write it first and reset the end
                 * pointer to the beginning of the buffer. */
                if (s->wend+left >= s->wtop && s->wptr <= s->wend) {
                    nwritten = s->wtop - s->wend;
                    memcpy(s->wend, buf, nwritten);
                    buf += nwritten;
                    left -= nwritten;
                    s->wend = s->wbuf;
                }
                /* Now we can copy a single chunk to wend. */
                if (s->wptr > s->wend)
                    maxwrite = s->wptr - s->wend - 1;
                else
                    maxwrite = left;  /* guaranteed to fit from above code */
            }
            if (left > maxwrite)
                nwritten = maxwrite;
            else
                nwritten = left;
            if (nwritten) {
                memcpy(s->wend, buf, nwritten);
                buf += nwritten;
                left -= nwritten;
                s->wend += nwritten;
            }
        }

        /* Now write to the socket as much as we can. */
        if (flush_write_buffer(s) < 0)
            RETURN_WITH(len - left);  /* socket is not valid any more */
        errno_save = errno;
        if (write_buffer_len(s) >= write_buffer_size(s)-1) {
            /* Write failed on full buffer; try to expand the buffer. */
            int over;
            uint32 more = resize_how_much(s, write_buffer_size(s), &over);
            if (more) {
                if (!resize_wbuf(s, write_buffer_size(s) + more)) {
                    /* It would be proper to block here, but if we ran out
                     * of memory the program's probably about to abort
                     * anyway, so just error out */
                    log("sockets: attempt to expand socket %d read buffer"
                        " failed (out of memory?)", s->fd);
                    errno_save = EAGAIN;
                    break;
                }
            } else {
                if ((s->flags & SF_BLOCKING) && !(s->flags & SF_WTRIGGER)) {
                    fd_set fds;
                    FD_ZERO(&fds);
                    FD_SET(s->fd, &fds);
                    if (select(s->fd+1, NULL, &fds, NULL, NULL) < 0) {
                        log("sockets: waiting on blocking socket %d: %s",
                            s->fd, strerror(errno));
                        break;
                    }
                    continue;  /* don't expand the buffer, since it's at max */
                } else {
#ifdef WARN_ON_BUFSIZE
                    if (!(s->flags & SF_WARNED)) {
                        log("sockets: socket %d exceeded %s buffer size"
                            " limit (%d)", s->fd,
                            over ? "per-connection" : "total",
                            over ? bufsize_limit : total_bufsize_limit);
                        s->flags |= SF_WARNED;
                    }
#endif
                    errno_save = EAGAIN;
                    break;
                }
            }
        }

    } /* while (left > 0) */

    errno = errno_save;
    RETURN_WITH(len - left);
}

/*************************************************************************/

/* Internal version of disconn(), used to pass a specific code to the
 * disconnect callback.  If code == DISCONN_LOCAL, attempt to first write
 * out any data left in the write buffer, and delay disconnection if we
 * can't.
 */

static int do_disconn(Socket *s, void *code)
{
    int errno_save = errno;  /* for passing to the callback */

    ENTER_WITH("%d", "%p,%p", s, code);
    if (s == NULL || (s->flags & SF_LISTENER)) {
        if (s)
            log("sockets: BUG: do_disconn(%d) with listener socket (%d)!",
                (int)(long)code, s->fd);
        else
            log("sockets: BUG: do_disconn(%d) with NULL socket!",
                (int)(long)code);
        errno = EINVAL;
        RETURN_WITH(-1);
    }
    if ((s->flags & SF_DISCONNECTING) && !((int)code & DISCONN_RESUME_FLAG))
        RETURN_WITH(0);
    if ((s->flags & SF_DISCONN_REQ) && code == DISCONN_LOCAL)
        RETURN_WITH(0);
    if (!(s->flags & (SF_CONNECTING | SF_CONNECTED)))
        RETURN_WITH(0);
    s->flags |= SF_DISCONN_REQ;
    FD_CLR(s->fd, &sock_fds);
    if (code == DISCONN_LOCAL && MORE_TO_WRITE(s)) {
        /* Write out any buffered data */
        if (flush_write_buffer(s) >= 0 && MORE_TO_WRITE(s)) {
            /* Some data is still buffered; request disconnect after it
             * goes out */
            s->flags |= SF_DISCONNECT;
            /* It's not technically disconnected yet, but it will (should)
             * succeed eventually */
            RETURN_WITH(0);
        }
    }
    s->flags |= SF_DISCONNECTING;
    if (code == DISCONN_REMOTE && (s->flags & SF_CALLBACK)) {
        /* Socket was closed while a callback was doing something; wait
         * until the callback finishes to actually close the socket */
        s->flags |= SF_BROKEN;
        RETURN_WITH(0);
    }
    shutdown(s->fd, 2);
    sock_closefd(s);
    while (s->writemap)
        next_wmap(s);
    s->writemap_tail = NULL;
    if (s->cb_disconn) {
        /* The disconnect callback doesn't need to check for disconnection,
         * so we just call it directly */
        errno = errno_save;
        s->cb_disconn(s, (void *)((int)code & ~DISCONN_RESUME_FLAG));
    }
    s->flags &= ~SF_DISCONNECTING;
    if (s->fd >= 0) {
        /* The socket was reconnected */
        return 0;
    }
    s->flags &= ~(SF_CONNECTING | SF_CONNECTED);
    if (s->flags & (SF_SELFCREATED | SF_DELETEME)) {
        if (s->flags & SF_CALLBACK)
            s->flags |= SF_DELETEME;
        else
            sock_free(s);
    } else {
        reclaim_buffer_space_one(s);
    }
    RETURN_WITH(0);
}

/*************************************************************************/

/* Close a socket's file descriptor, and clear it from all associated
 * structures (s->fd, sockets[], sock_fds, write_fds).
 */

static void sock_closefd(Socket *s)
{
    ENTER("%p", s);
    /* FIXME: apparently it's possible to come here twice for the same
     * connection; under what circumstances can that happen? */
    if (s->fd >= 0) {
        close(s->fd);
        FD_CLR(s->fd, &sock_fds);
        FD_CLR(s->fd, &write_fds);
        sockets[s->fd] = NULL;
        s->fd = -1;
    }
    RETURN;
}

/*************************************************************************/

/*
 * Local variables:
 *   c-file-style: "stroustrup"
 *   c-file-offsets: ((case-label . *) (statement-case-intro . *))
 *   indent-tabs-mode: nil
 * End:
 *
 * vim: expandtab shiftwidth=4:
 */
Revision:	1171
Committed:	Fri Aug 12 20:00:46 2011 UTC (12 years, 8 months ago) by michael
Content type:	text/x-csrc
File size:	72138 byte(s)
Log Message:	- Import ircservices-5.1.24. Don't ever think about modifying anything in this folder! Since Andrew Church has discontinued his services project in April 2011, the ircd-hybrid team has been given permissions to officially continue and maintain the already mentioned project. The name of this project will be changed for the reason being that the current name "IRC Services" is way too generic these days. Remember: Don't ever modify anything in here. This folder is kept for reference.