trunk/src/fdlist.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2018 ircd-hybrid development team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 *  USA
 */

/*! \file fdlist.c
 * \brief Maintains a list of file descriptors.
 * \version $Id$
 */

#include "stdinc.h"
#include "fdlist.h"
#include "irc_string.h"
#include "s_bsd.h"   /* comm_setselect */
#include "memory.h"
#include "misc.h"
#include "res.h"


fde_t *fd_table;
int number_fd = LEAKED_FDS;
int hard_fdlimit = 0;
int highest_fd = -1;


void
fdlist_init(void)
{
  struct rlimit limit;

  if (!getrlimit(RLIMIT_NOFILE, &limit))
  {
    limit.rlim_cur = limit.rlim_max;
    setrlimit(RLIMIT_NOFILE, &limit);
  }

  /* allow MAXCLIENTS_MIN clients even at the cost of MAX_BUFFER and
   * some not really LEAKED_FDS */
  hard_fdlimit = IRCD_MAX(getdtablesize(), LEAKED_FDS + MAX_BUFFER + MAXCLIENTS_MIN);
  fd_table = xcalloc(sizeof(fde_t) * hard_fdlimit);
}

static void
fdlist_update_highest_fd(int fd, int opening)
{
  if (fd < highest_fd)
    return;

  assert(fd < hard_fdlimit);

  if (fd > highest_fd)
  {
    /*
     * assert() that we are not closing a FD bigger than our known highest FD.
     */
    assert(opening);
    highest_fd = fd;
    return;
  }

  /* If we are here, then fd == highest_fd */
  /*
   * assert() that we are closing the highest FD; we can't be re-opening it.
   */
  assert(!opening);

  while (highest_fd >= 0 && fd_table[highest_fd].flags.open == 0)
    --highest_fd;
}

/* Called to open a given filedescriptor */
fde_t *
fd_open(int fd, int is_socket, const char *desc)
{
  fde_t *F = &fd_table[fd];

  assert(fd >= 0);
  assert(F->fd == 0);
  assert(F->flags.open == 0);

  /*
   * Note: normally we'd have to clear the other flags, but currently F
   * is always cleared before calling us.
   */
  F->fd = fd;
  F->comm_index = -1;
  F->flags.open = 1;
  F->flags.is_socket = is_socket;

  if (desc)
    strlcpy(F->desc, desc, sizeof(F->desc));

  ++number_fd;
  fdlist_update_highest_fd(fd, 1);

  return F;
}

/* Called to close a given filedescriptor */
void
fd_close(fde_t *F)
{
  const int fd = F->fd;

  assert(F->fd >= 0);
  assert(F->flags.open);

  if (F->flags.is_socket)
    comm_setselect(F, COMM_SELECT_WRITE | COMM_SELECT_READ, NULL, NULL, 0);

  delete_resolver_queries(F);

  if (tls_isusing(&F->ssl))
    tls_free(&F->ssl);

  /* Unlike squid, we're actually closing the FD here! -- adrian */
  close(F->fd);
  memset(F, 0, sizeof(*F));  /* Must set F->flags.open == 0 before fdlist_update_highest_fd() */

  --number_fd;
  fdlist_update_highest_fd(fd, 0);
}

/*
 * fd_note() - set the fd note
 *
 * Note: must be careful not to overflow fd_table[fd].desc when
 *       calling.
 */
void
fd_note(fde_t *F, const char *format, ...)
{
  va_list args;

  if (format)
  {
    va_start(args, format);
    vsnprintf(F->desc, sizeof(F->desc), format, args);
    va_end(args);
  }
  else
    F->desc[0] = '\0';
}

/* Make sure stdio descriptors (0-2) and profiler descriptor (3)
 * always go somewhere harmless.  Use -foreground for profiling
 * or executing from gdb */
void
close_standard_fds(void)
{
  for (int i = 0; i < LOWEST_SAFE_FD; ++i)
  {
    close(i);

    if (open("/dev/null", O_RDWR) < 0)
      exit(EXIT_FAILURE); /* we're hosed if we can't even open /dev/null */
  }
}

void
close_fds(void)
{
  for (int fd = 0; fd <= highest_fd; ++fd)
    close(fd);
}
Revision:	8520
Committed:	Mon Apr 16 19:32:31 2018 UTC (7 years, 4 months ago) by michael
Content type:	text/x-csrc
File size:	4099 byte(s)
Log Message:	- fdlist.c: initialize 'highest_fd' with -1 so we don't run into problems if we ever have a fd == 0 in fdlist_update_highest_fd(), which currently is highly unlikely
#	User	Rev	Content
1	adx	30	/*
2	michael	2916	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	adx	30	*
4	michael	8279	* Copyright (c) 1997-2018 ircd-hybrid development team
5	adx	30	*
6			* This program is free software; you can redistribute it and/or modify
7			* it under the terms of the GNU General Public License as published by
8			* the Free Software Foundation; either version 2 of the License, or
9			* (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18	michael	4565	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	adx	30	* USA
20			*/
21	michael	1243
22	michael	2916	/*! \file fdlist.c
23			* \brief Maintains a list of file descriptors.
24			* \version $Id$
25			*/
26
27	adx	30	#include "stdinc.h"
28			#include "fdlist.h"
29			#include "irc_string.h"
30			#include "s_bsd.h" /* comm_setselect */
31			#include "memory.h"
32	michael	3347	#include "misc.h"
33	michael	3322	#include "res.h"
34	adx	30
35	michael	8365
36	michael	8339	fde_t *fd_table;
37	adx	30	int number_fd = LEAKED_FDS;
38			int hard_fdlimit = 0;
39	michael	8520	int highest_fd = -1;
40	adx	30
41
42	michael	4878	void
43			fdlist_init(void)
44	adx	30	{
45			struct rlimit limit;
46
47	michael	1236	if (!getrlimit(RLIMIT_NOFILE, &limit))
48	adx	30	{
49			limit.rlim_cur = limit.rlim_max;
50	michael	1236	setrlimit(RLIMIT_NOFILE, &limit);
51	adx	30	}
52
53			/* allow MAXCLIENTS_MIN clients even at the cost of MAX_BUFFER and
54			* some not really LEAKED_FDS */
55	michael	8339	hard_fdlimit = IRCD_MAX(getdtablesize(), LEAKED_FDS + MAX_BUFFER + MAXCLIENTS_MIN);
56			fd_table = xcalloc(sizeof(fde_t) * hard_fdlimit);
57	adx	30	}
58
59	michael	8339	static void
60			fdlist_update_highest_fd(int fd, int opening)
61	adx	30	{
62	michael	8339	if (fd < highest_fd)
63			return;
64	adx	30
65	michael	8339	assert(fd < hard_fdlimit);
66	adx	30
67	michael	8339	if (fd > highest_fd)
68	adx	30	{
69	michael	8339	/*
70			* assert() that we are not closing a FD bigger than our known highest FD.
71			*/
72			assert(opening);
73			highest_fd = fd;
74			return;
75	adx	30	}
76
77	michael	8339	/* If we are here, then fd == highest_fd */
78			/*
79			* assert() that we are closing the highest FD; we can't be re-opening it.
80			*/
81			assert(!opening);
82
83			while (highest_fd >= 0 && fd_table[highest_fd].flags.open == 0)
84			--highest_fd;
85	adx	30	}
86
87			/* Called to open a given filedescriptor */
88	michael	8339	fde_t *
89			fd_open(int fd, int is_socket, const char *desc)
90	adx	30	{
91	michael	8339	fde_t *F = &fd_table[fd];
92	michael	5590
93	adx	30	assert(fd >= 0);
94	michael	8339	assert(F->fd == 0);
95			assert(F->flags.open == 0);
96	adx	30
97	michael	8339	/*
98			* Note: normally we'd have to clear the other flags, but currently F
99			* is always cleared before calling us.
100			*/
101	adx	30	F->fd = fd;
102			F->comm_index = -1;
103	michael	8339	F->flags.open = 1;
104			F->flags.is_socket = is_socket;
105	michael	3602
106	adx	30	if (desc)
107			strlcpy(F->desc, desc, sizeof(F->desc));
108	michael	3602
109	michael	8339	++number_fd;
110			fdlist_update_highest_fd(fd, 1);
111	adx	30
112	michael	8339	return F;
113	adx	30	}
114
115			/* Called to close a given filedescriptor */
116			void
117			fd_close(fde_t *F)
118			{
119	michael	8339	const int fd = F->fd;
120	adx	30
121	michael	8339	assert(F->fd >= 0);
122	michael	5590	assert(F->flags.open);
123
124	adx	30	if (F->flags.is_socket)
125			comm_setselect(F, COMM_SELECT_WRITE \| COMM_SELECT_READ, NULL, NULL, 0);
126
127	michael	992	delete_resolver_queries(F);
128	adx	30
129	michael	7105	if (tls_isusing(&F->ssl))
130			tls_free(&F->ssl);
131	adx	30
132			/* Unlike squid, we're actually closing the FD here! -- adrian */
133			close(F->fd);
134	michael	8339	memset(F, 0, sizeof(F)); / Must set F->flags.open == 0 before fdlist_update_highest_fd() */
135	michael	436
136	michael	8339	--number_fd;
137			fdlist_update_highest_fd(fd, 0);
138	adx	30	}
139
140			/*
141			* fd_note() - set the fd note
142			*
143			* Note: must be careful not to overflow fd_table[fd].desc when
144			* calling.
145			*/
146			void
147			fd_note(fde_t F, const char format, ...)
148			{
149			va_list args;
150
151	michael	3600	if (format)
152	adx	30	{
153			va_start(args, format);
154			vsnprintf(F->desc, sizeof(F->desc), format, args);
155			va_end(args);
156			}
157			else
158			F->desc[0] = '\0';
159			}
160
161			/* Make sure stdio descriptors (0-2) and profiler descriptor (3)
162			* always go somewhere harmless. Use -foreground for profiling
163			* or executing from gdb */
164			void
165			close_standard_fds(void)
166			{
167	michael	8339	for (int i = 0; i < LOWEST_SAFE_FD; ++i)
168	adx	30	{
169			close(i);
170	michael	3600
171	michael	1329	if (open("/dev/null", O_RDWR) < 0)
172	michael	6553	exit(EXIT_FAILURE); /* we're hosed if we can't even open /dev/null */
173	adx	30	}
174			}
175
176			void
177	michael	8339	close_fds(void)
178	adx	30	{
179	michael	8339	for (int fd = 0; fd <= highest_fd; ++fd)
180			close(fd);
181	adx	30	}