mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-01 17:30:07 +00:00
472 lines
11 KiB
C
472 lines
11 KiB
C
/* Mail alias file parser in nss_files module.
|
||
Copyright (C) 1996-1999,2002,2006,2007,2011 Free Software Foundation, Inc.
|
||
This file is part of the GNU C Library.
|
||
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
|
||
|
||
The GNU C Library is free software; you can redistribute it and/or
|
||
modify it under the terms of the GNU Lesser General Public
|
||
License as published by the Free Software Foundation; either
|
||
version 2.1 of the License, or (at your option) any later version.
|
||
|
||
The GNU C Library 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
|
||
Lesser General Public License for more details.
|
||
|
||
You should have received a copy of the GNU Lesser General Public
|
||
License along with the GNU C Library; if not, see
|
||
<http://www.gnu.org/licenses/>. */
|
||
|
||
#include <aliases.h>
|
||
#include <ctype.h>
|
||
#include <errno.h>
|
||
#include <fcntl.h>
|
||
#include <bits/libc-lock.h>
|
||
#include <stdlib.h>
|
||
#include <stdio.h>
|
||
#include <string.h>
|
||
|
||
#include <kernel-features.h>
|
||
|
||
#include "nsswitch.h"
|
||
|
||
/* Locks the static variables in this file. */
|
||
__libc_lock_define_initialized (static, lock)
|
||
|
||
/* Maintenance of the shared stream open on the database file. */
|
||
|
||
static FILE *stream;
|
||
static fpos_t position;
|
||
static enum { nouse, getent, getby } last_use;
|
||
|
||
|
||
static enum nss_status
|
||
internal_setent (void)
|
||
{
|
||
enum nss_status status = NSS_STATUS_SUCCESS;
|
||
|
||
if (stream == NULL)
|
||
{
|
||
stream = fopen ("/etc/aliases", "rce");
|
||
|
||
if (stream == NULL)
|
||
status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
|
||
else
|
||
{
|
||
#if !defined O_CLOEXEC || !defined __ASSUME_O_CLOEXEC
|
||
# ifdef O_CLOEXEC
|
||
if (__have_o_cloexec <= 0)
|
||
# endif
|
||
{
|
||
/* We have to make sure the file is `closed on exec'. */
|
||
int result;
|
||
int flags;
|
||
|
||
result = flags = fcntl (fileno (stream), F_GETFD, 0);
|
||
if (result >= 0)
|
||
{
|
||
# ifdef O_CLOEXEC
|
||
if (__have_o_cloexec == 0)
|
||
__have_o_cloexec = (flags & FD_CLOEXEC) == 0 ? -1 : 1;
|
||
if (__have_o_cloexec < 0)
|
||
# endif
|
||
{
|
||
flags |= FD_CLOEXEC;
|
||
result = fcntl (fileno (stream), F_SETFD, flags);
|
||
}
|
||
}
|
||
if (result < 0)
|
||
{
|
||
/* Something went wrong. Close the stream and return a
|
||
failure. */
|
||
fclose (stream);
|
||
stream = NULL;
|
||
status = NSS_STATUS_UNAVAIL;
|
||
}
|
||
}
|
||
#endif
|
||
}
|
||
}
|
||
else
|
||
rewind (stream);
|
||
|
||
return status;
|
||
}
|
||
|
||
|
||
/* Thread-safe, exported version of that. */
|
||
enum nss_status
|
||
_nss_files_setaliasent (void)
|
||
{
|
||
enum nss_status status;
|
||
|
||
__libc_lock_lock (lock);
|
||
|
||
status = internal_setent ();
|
||
|
||
if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0)
|
||
{
|
||
fclose (stream);
|
||
stream = NULL;
|
||
status = NSS_STATUS_UNAVAIL;
|
||
}
|
||
|
||
last_use = getent;
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
return status;
|
||
}
|
||
|
||
|
||
/* Close the database file. */
|
||
static void
|
||
internal_endent (void)
|
||
{
|
||
if (stream != NULL)
|
||
{
|
||
fclose (stream);
|
||
stream = NULL;
|
||
}
|
||
}
|
||
|
||
|
||
/* Thread-safe, exported version of that. */
|
||
enum nss_status
|
||
_nss_files_endaliasent (void)
|
||
{
|
||
__libc_lock_lock (lock);
|
||
|
||
internal_endent ();
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
return NSS_STATUS_SUCCESS;
|
||
}
|
||
|
||
/* Parsing the database file into `struct aliasent' data structures. */
|
||
static enum nss_status
|
||
get_next_alias (const char *match, struct aliasent *result,
|
||
char *buffer, size_t buflen, int *errnop)
|
||
{
|
||
enum nss_status status = NSS_STATUS_NOTFOUND;
|
||
int ignore = 0;
|
||
|
||
result->alias_members_len = 0;
|
||
|
||
while (1)
|
||
{
|
||
/* Now we are ready to process the input. We have to read a
|
||
line and all its continuations and construct the array of
|
||
string pointers. This pointers and the names itself have to
|
||
be placed in BUFFER. */
|
||
char *first_unused = buffer;
|
||
size_t room_left = buflen - (buflen % __alignof__ (char *));
|
||
char *line;
|
||
|
||
/* Check whether the buffer is large enough for even trying to
|
||
read something. */
|
||
if (room_left < 2)
|
||
goto no_more_room;
|
||
|
||
/* Read the first line. It must contain the alias name and
|
||
possibly some alias names. */
|
||
first_unused[room_left - 1] = '\xff';
|
||
line = fgets_unlocked (first_unused, room_left, stream);
|
||
if (line == NULL)
|
||
/* Nothing to read. */
|
||
break;
|
||
else if (first_unused[room_left - 1] != '\xff')
|
||
{
|
||
/* The line is too long for our buffer. */
|
||
no_more_room:
|
||
*errnop = ERANGE;
|
||
status = NSS_STATUS_TRYAGAIN;
|
||
break;
|
||
}
|
||
else
|
||
{
|
||
char *cp;
|
||
|
||
/* If we are in IGNORE mode and the first character in the
|
||
line is a white space we ignore the line and start
|
||
reading the next. */
|
||
if (ignore && isspace (*first_unused))
|
||
continue;
|
||
|
||
/* Terminate the line for any case. */
|
||
cp = strpbrk (first_unused, "#\n");
|
||
if (cp != NULL)
|
||
*cp = '\0';
|
||
|
||
/* Skip leading blanks. */
|
||
while (isspace (*line))
|
||
++line;
|
||
|
||
result->alias_name = first_unused;
|
||
while (*line != '\0' && *line != ':')
|
||
*first_unused++ = *line++;
|
||
if (*line == '\0' || result->alias_name == first_unused)
|
||
/* No valid name. Ignore the line. */
|
||
continue;
|
||
|
||
*first_unused++ = '\0';
|
||
if (room_left < (size_t) (first_unused - result->alias_name))
|
||
goto no_more_room;
|
||
room_left -= first_unused - result->alias_name;
|
||
++line;
|
||
|
||
/* When we search for a specific alias we can avoid all the
|
||
difficult parts and compare now with the name we are
|
||
looking for. If it does not match we simply ignore all
|
||
lines until the next line containing the start of a new
|
||
alias is found. */
|
||
ignore = (match != NULL
|
||
&& __strcasecmp (result->alias_name, match) != 0);
|
||
|
||
while (! ignore)
|
||
{
|
||
while (isspace (*line))
|
||
++line;
|
||
|
||
cp = first_unused;
|
||
while (*line != '\0' && *line != ',')
|
||
*first_unused++ = *line++;
|
||
|
||
if (first_unused != cp)
|
||
{
|
||
/* OK, we can have a regular entry or an include
|
||
request. */
|
||
if (*line != '\0')
|
||
++line;
|
||
*first_unused++ = '\0';
|
||
|
||
if (strncmp (cp, ":include:", 9) != 0)
|
||
{
|
||
if (room_left < (first_unused - cp) + sizeof (char *))
|
||
goto no_more_room;
|
||
room_left -= (first_unused - cp) + sizeof (char *);
|
||
|
||
++result->alias_members_len;
|
||
}
|
||
else
|
||
{
|
||
/* Oh well, we have to read the addressed file. */
|
||
FILE *listfile;
|
||
char *old_line = NULL;
|
||
|
||
first_unused = cp;
|
||
|
||
listfile = fopen (&cp[9], "rce");
|
||
/* If the file does not exist we simply ignore
|
||
the statement. */
|
||
if (listfile != NULL
|
||
&& (old_line = strdup (line)) != NULL)
|
||
{
|
||
while (! feof_unlocked (listfile))
|
||
{
|
||
first_unused[room_left - 1] = '\xff';
|
||
line = fgets_unlocked (first_unused, room_left,
|
||
listfile);
|
||
if (line == NULL)
|
||
break;
|
||
if (first_unused[room_left - 1] != '\xff')
|
||
{
|
||
free (old_line);
|
||
goto no_more_room;
|
||
}
|
||
|
||
/* Parse the line. */
|
||
cp = strpbrk (line, "#\n");
|
||
if (cp != NULL)
|
||
*cp = '\0';
|
||
|
||
do
|
||
{
|
||
while (isspace (*line))
|
||
++line;
|
||
|
||
cp = first_unused;
|
||
while (*line != '\0' && *line != ',')
|
||
*first_unused++ = *line++;
|
||
|
||
if (*line != '\0')
|
||
++line;
|
||
|
||
if (first_unused != cp)
|
||
{
|
||
*first_unused++ = '\0';
|
||
if (room_left < ((first_unused - cp)
|
||
+ __alignof__ (char *)))
|
||
{
|
||
free (old_line);
|
||
goto no_more_room;
|
||
}
|
||
room_left -= ((first_unused - cp)
|
||
+ __alignof__ (char *));
|
||
++result->alias_members_len;
|
||
}
|
||
}
|
||
while (*line != '\0');
|
||
}
|
||
fclose (listfile);
|
||
|
||
first_unused[room_left - 1] = '\0';
|
||
strncpy (first_unused, old_line, room_left);
|
||
|
||
free (old_line);
|
||
line = first_unused;
|
||
|
||
if (first_unused[room_left - 1] != '\0')
|
||
goto no_more_room;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (*line == '\0')
|
||
{
|
||
/* Get the next line. But we must be careful. We
|
||
must not read the whole line at once since it
|
||
might belong to the current alias. Simply read
|
||
the first character. If it is a white space we
|
||
have a continuation line. Otherwise it is the
|
||
beginning of a new alias and we can push back the
|
||
just read character. */
|
||
int ch;
|
||
|
||
ch = fgetc_unlocked (stream);
|
||
if (ch == EOF || ch == '\n' || !isspace (ch))
|
||
{
|
||
size_t cnt;
|
||
|
||
/* Now prepare the return. Provide string
|
||
pointers for the currently selected aliases. */
|
||
if (ch != EOF)
|
||
ungetc (ch, stream);
|
||
|
||
/* Adjust the pointer so it is aligned for
|
||
storing pointers. */
|
||
first_unused += __alignof__ (char *) - 1;
|
||
first_unused -= ((first_unused - (char *) 0)
|
||
% __alignof__ (char *));
|
||
result->alias_members = (char **) first_unused;
|
||
|
||
/* Compute addresses of alias entry strings. */
|
||
cp = result->alias_name;
|
||
for (cnt = 0; cnt < result->alias_members_len; ++cnt)
|
||
{
|
||
cp = strchr (cp, '\0') + 1;
|
||
result->alias_members[cnt] = cp;
|
||
}
|
||
|
||
status = (result->alias_members_len == 0
|
||
? NSS_STATUS_RETURN : NSS_STATUS_SUCCESS);
|
||
break;
|
||
}
|
||
|
||
/* The just read character is a white space and so
|
||
can be ignored. */
|
||
first_unused[room_left - 1] = '\xff';
|
||
line = fgets_unlocked (first_unused, room_left, stream);
|
||
if (first_unused[room_left - 1] != '\xff')
|
||
goto no_more_room;
|
||
cp = strpbrk (line, "#\n");
|
||
if (cp != NULL)
|
||
*cp = '\0';
|
||
}
|
||
}
|
||
}
|
||
|
||
if (status != NSS_STATUS_NOTFOUND)
|
||
/* We read something. In any case break here. */
|
||
break;
|
||
}
|
||
|
||
return status;
|
||
}
|
||
|
||
|
||
enum nss_status
|
||
_nss_files_getaliasent_r (struct aliasent *result, char *buffer, size_t buflen,
|
||
int *errnop)
|
||
{
|
||
/* Return next entry in host file. */
|
||
enum nss_status status = NSS_STATUS_SUCCESS;
|
||
|
||
__libc_lock_lock (lock);
|
||
|
||
/* Be prepared that the set*ent function was not called before. */
|
||
if (stream == NULL)
|
||
status = internal_setent ();
|
||
|
||
if (status == NSS_STATUS_SUCCESS)
|
||
{
|
||
/* If the last use was not by the getent function we need the
|
||
position the stream. */
|
||
if (last_use != getent)
|
||
{
|
||
if (fsetpos (stream, &position) < 0)
|
||
status = NSS_STATUS_UNAVAIL;
|
||
else
|
||
last_use = getent;
|
||
}
|
||
|
||
if (status == NSS_STATUS_SUCCESS)
|
||
{
|
||
result->alias_local = 1;
|
||
|
||
/* Read lines until we get a definite result. */
|
||
do
|
||
status = get_next_alias (NULL, result, buffer, buflen, errnop);
|
||
while (status == NSS_STATUS_RETURN);
|
||
|
||
/* If we successfully read an entry remember this position. */
|
||
if (status == NSS_STATUS_SUCCESS)
|
||
fgetpos (stream, &position);
|
||
else
|
||
last_use = nouse;
|
||
}
|
||
}
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
return status;
|
||
}
|
||
|
||
|
||
enum nss_status
|
||
_nss_files_getaliasbyname_r (const char *name, struct aliasent *result,
|
||
char *buffer, size_t buflen, int *errnop)
|
||
{
|
||
/* Return next entry in host file. */
|
||
enum nss_status status = NSS_STATUS_SUCCESS;
|
||
|
||
if (name == NULL)
|
||
{
|
||
__set_errno (EINVAL);
|
||
return NSS_STATUS_UNAVAIL;
|
||
}
|
||
|
||
__libc_lock_lock (lock);
|
||
|
||
/* Open the stream or rest it. */
|
||
status = internal_setent ();
|
||
last_use = getby;
|
||
|
||
if (status == NSS_STATUS_SUCCESS)
|
||
{
|
||
result->alias_local = 1;
|
||
|
||
/* Read lines until we get a definite result. */
|
||
do
|
||
status = get_next_alias (name, result, buffer, buflen, errnop);
|
||
while (status == NSS_STATUS_RETURN);
|
||
}
|
||
|
||
internal_endent ();
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
return status;
|
||
}
|