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/*
* Copyright (C) 1996-2000 Michael R. Elkins <me@mutt.org>
* Copyright (C) 1998-2001,2007 Thomas Roessler <roessler@does-not-exist.org>
*
* 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.
*/
/*
* This module either be compiled into Mutt, or it can be
* built as a separate program. For building it
* separately, define the DL_STANDALONE preprocessor
* macro.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <errno.h>
#include <time.h>
#include <fcntl.h>
#include <limits.h>
#ifndef _POSIX_PATH_MAX
#include <limits.h>
#endif
#include "version.h"
#include "dotlock.h"
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#ifdef DL_STANDALONE
# include "reldate.h"
#endif
#define MAXLINKS 1024 /* maximum link depth */
#ifdef DL_STANDALONE
# define LONG_STRING 1024
# define MAXLOCKATTEMPT 5
# define strfcpy(A,B,C) strncpy (A,B,C), *(A+(C)-1)=0
# ifdef USE_SETGID
# ifdef HAVE_SETEGID
# define SETEGID setegid
# else
# define SETEGID setgid
# endif
# ifndef S_ISLNK
# define S_ISLNK(x) (((x) & S_IFMT) == S_IFLNK ? 1 : 0)
# endif
# endif
#else /* DL_STANDALONE */
# ifdef USE_SETGID
# error Do not try to compile dotlock as a mutt module when requiring egid switching!
# endif
# include "mutt.h"
# include "mx.h"
#endif /* DL_STANDALONE */
static int DotlockFlags;
static int Retry = MAXLOCKATTEMPT;
#ifdef DL_STANDALONE
static char *Hostname;
#endif
#ifdef USE_SETGID
static gid_t UserGid;
static gid_t MailGid;
#endif
static int dotlock_deference_symlink (char *, size_t, const char *);
static int dotlock_prepare (char *, size_t, const char *, int fd);
static int dotlock_check_stats (struct stat *, struct stat *);
static int dotlock_dispatch (const char *, int fd);
#ifdef DL_STANDALONE
static int dotlock_init_privs (void);
static void usage (const char *);
#endif
static void dotlock_expand_link (char *, const char *, const char *);
static void BEGIN_PRIVILEGED (void);
static void END_PRIVILEGED (void);
/* These functions work on the current directory.
* Invoke dotlock_prepare () before and check their
* return value.
*/
static int dotlock_try (void);
static int dotlock_unlock (const char *);
static int dotlock_unlink (const char *);
static int dotlock_lock (const char *);
#ifdef DL_STANDALONE
#define check_flags(a) if (a & DL_FL_ACTIONS) usage (argv[0])
int main (int argc, char **argv)
{
int i;
char *p;
struct utsname utsname;
/* first, drop privileges */
if (dotlock_init_privs () == -1)
return DL_EX_ERROR;
/* determine the system's host name */
uname (&utsname);
if (!(Hostname = strdup (utsname.nodename))) /* __MEM_CHECKED__ */
return DL_EX_ERROR;
if ((p = strchr (Hostname, '.')))
*p = '\0';
/* parse the command line options. */
DotlockFlags = 0;
while ((i = getopt (argc, argv, "dtfupr:")) != EOF)
{
switch (i)
{
/* actions, mutually exclusive */
case 't': check_flags (DotlockFlags); DotlockFlags |= DL_FL_TRY; break;
case 'd': check_flags (DotlockFlags); DotlockFlags |= DL_FL_UNLINK; break;
case 'u': check_flags (DotlockFlags); DotlockFlags |= DL_FL_UNLOCK; break;
/* other flags */
case 'f': DotlockFlags |= DL_FL_FORCE; break;
case 'p': DotlockFlags |= DL_FL_USEPRIV; break;
case 'r': DotlockFlags |= DL_FL_RETRY; Retry = atoi (optarg); break;
default: usage (argv[0]);
}
}
if (optind == argc || Retry < 0)
usage (argv[0]);
return dotlock_dispatch (argv[optind], -1);
}
/*
* Determine our effective group ID, and drop
* privileges.
*
* Return value:
*
* 0 - everything went fine
* -1 - we couldn't drop privileges.
*
*/
static int
dotlock_init_privs (void)
{
# ifdef USE_SETGID
UserGid = getgid ();
MailGid = getegid ();
if (SETEGID (UserGid) != 0)
return -1;
# endif
return 0;
}
#else /* DL_STANDALONE */
/*
* This function is intended to be invoked from within
* mutt instead of mx.c's invoke_dotlock ().
*/
int dotlock_invoke (const char *path, int fd, int flags, int retry)
{
int currdir;
int r;
DotlockFlags = flags;
if ((currdir = open (".", O_RDONLY)) == -1)
return DL_EX_ERROR;
if (!(DotlockFlags & DL_FL_RETRY) || retry)
Retry = MAXLOCKATTEMPT;
else
Retry = 0;
r = dotlock_dispatch (path, fd);
fchdir (currdir);
close (currdir);
return r;
}
#endif /* DL_STANDALONE */
static int dotlock_dispatch (const char *f, int fd)
{
char realpath[_POSIX_PATH_MAX];
/* If dotlock_prepare () succeeds [return value == 0],
* realpath contains the basename of f, and we have
* successfully changed our working directory to
* `dirname $f`. Additionally, f has been opened for
* reading to verify that the user has at least read
* permissions on that file.
*
* For a more detailed explanation of all this, see the
* lengthy comment below.
*/
if (dotlock_prepare (realpath, sizeof (realpath), f, fd) != 0)
return DL_EX_ERROR;
/* Actually perform the locking operation. */
if (DotlockFlags & DL_FL_TRY)
return dotlock_try ();
else if (DotlockFlags & DL_FL_UNLOCK)
return dotlock_unlock (realpath);
else if (DotlockFlags & DL_FL_UNLINK)
return dotlock_unlink (realpath);
else /* lock */
return dotlock_lock (realpath);
}
/*
* Get privileges
*
* This function re-acquires the privileges we may have
* if the user told us to do so by giving the "-p"
* command line option.
*
* BEGIN_PRIVILEGES () won't return if an error occurs.
*
*/
static void
BEGIN_PRIVILEGED (void)
{
#ifdef USE_SETGID<
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