/* -*- mode: C; c-file-style: "gnu" -*- */
/* dbus-sysdeps-util-unix.c Would be in dbus-sysdeps-unix.c, but not used in libdbus
*
* Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc.
* Copyright (C) 2003 CodeFactory AB
*
* Licensed under the Academic Free License version 2.1
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "dbus-sysdeps.h"
#include "dbus-sysdeps-unix.h"
#include "dbus-internals.h"
#include "dbus-protocol.h"
#include "dbus-string.h"
#define DBUS_USERDB_INCLUDES_PRIVATE 1
#include "dbus-userdb.h"
#include "dbus-test.h"
#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <grp.h>
#include <sys/socket.h>
#include <dirent.h>
#include <sys/un.h>
#ifdef HAVE_SYS_SYSLIMITS_H
#include <sys/syslimits.h>
#endif
#ifndef O_BINARY
#define O_BINARY 0
#endif
/**
* @addtogroup DBusInternalsUtils
* @{
*/
/**
* Does the chdir, fork, setsid, etc. to become a daemon process.
*
* @param pidfile #NULL, or pidfile to create
* @param print_pid_fd file descriptor to print daemon's pid to, or -1 for none
* @param error return location for errors
* @returns #FALSE on failure
*/
dbus_bool_t
_dbus_become_daemon (const DBusString *pidfile,
int print_pid_fd,
DBusError *error)
{
const char *s;
pid_t child_pid;
int dev_null_fd;
_dbus_verbose ("Becoming a daemon...\n");
_dbus_verbose ("chdir to /\n");
if (chdir ("/") < 0)
{
dbus_set_error (error, DBUS_ERROR_FAILED,
"Could not chdir() to root directory");
return FALSE;
}
_dbus_verbose ("forking...\n");
switch ((child_pid = fork ()))
{
case -1:
_dbus_verbose ("fork failed\n");
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to fork daemon: %s", _dbus_strerror (errno));
return FALSE;
break;
case 0:
_dbus_verbose ("in child, closing std file descriptors\n");
/* silently ignore failures here, if someone
* doesn't have /dev/null we may as well try
* to continue anyhow
*/
dev_null_fd = open ("/dev/null", O_RDWR);
if (dev_null_fd >= 0)
{
dup2 (dev_null_fd, 0);
dup2 (dev_null_fd, 1);
s = _dbus_getenv ("DBUS_DEBUG_OUTPUT");
if (s == NULL || *s == '\0')
dup2 (dev_null_fd, 2);
else
_dbus_verbose ("keeping stderr open due to DBUS_DEBUG_OUTPUT\n");
}
/* Get a predictable umask */
_dbus_verbose ("setting umask\n");
umask (022);
break;
default:
if (pidfile)
{
_dbus_verbose ("parent writing pid file\n");
if (!_dbus_write_pid_file (pidfile,
child_pid,
error))
{
_dbus_verbose ("pid file write failed, killing child\n");
kill (child_pid, SIGTERM);
return FALSE;
}
}
/* Write PID if requested */
if (print_pid_fd >= 0)
{
DBusString pid;
int bytes;
if (!_dbus_string_init (&pid))
{
_DBUS_SET_OOM (error);
kill (child_pid, SIGTERM);
return FALSE;
}
if (!_dbus_string_append_int (&pid, child_pid) ||
!_dbus_string_append (&pid, "\n"))
{
_dbus_string_free (&pid);
_DBUS_SET_OOM (error);
kill (child_pid, SIGTERM);
return FALSE;
}
bytes = _dbus_string_get_length (&pid);
if (_dbus_write_socket (print_pid_fd, &pid, 0, bytes) != bytes)
{
dbus_set_error (error, DBUS_ERROR_FAILED,
"Printing message bus PID: %s\n",
_dbus_strerror (errno));
_dbus_string_free (&pid);
kill (child_pid, SIGTERM);
return FALSE;
}
_dbus_string_free (&pid);
}
_dbus_verbose ("parent exiting\n");
_exit (0);
break;
}
_dbus_verbose ("calling setsid()\n");
if (setsid () == -1)
_dbus_assert_not_reached ("setsid() failed");
return TRUE;
}
/**
* Creates a file containing the process ID.
*
* @param filename the filename to write to
* @param pid our process ID
* @param error return location for errors
* @returns #FALSE on failure
*/
dbus_bool_t
_dbus_write_pid_file (const DBusString *filename,
unsigned long pid,
DBusError *error)
{
const char *cfilename;
int fd;
FILE *f;
cfilename = _dbus_string_get_const_data (filename);
fd = open (cfilename, O_WRONLY|O_CREAT|O_EXCL|O_BINARY, 0644);
if (fd < 0)
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to open \"%s\": %s", cfilename,
_dbus_strerror (errno));
return FALSE;
}
if ((f = fdopen (fd, "w")) == NULL)
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to fdopen fd %d: %s", fd, _dbus_strerror (errno));
_dbus_close (fd, NULL);
return FALSE;
}
if (fprintf (f, "%lu\n", pid) < 0)
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to write to \"%s\": %s", cfilename,
_dbus_strerror (errno));
fclose (f);
return FALSE;
}
if (fclose (f) == EOF)
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to close \"%s\": %s", cfilename,
_dbus_strerror (errno));
return FALSE;
}
return TRUE;
}
/**
* Changes the user and group the bus is running as.
*
* @param uid the new user ID
* @param gid the new group ID
* @param error return location for errors
* @returns #FALSE on failure
*/
dbus_bool_t
_dbus_change_identity (dbus_uid_t uid,
dbus_gid_t gid,
DBusError *error)
{
/* setgroups() only works if we are a privileged process,
* so we don't return error on failure; the only possible
* failure is that we don't have perms to do it.
*
* not sure this is right, maybe if setuid()
* is going to work then setgroups() should also work.
*/
if (setgroups (0, NULL) < 0)
_dbus_warn ("Failed to drop supplementary groups: %s\n",
_dbus_strerror (errno));
/* Set GID first, or the setuid may remove our permission
* to change the GID
*/
if (setgid (gid) < 0)
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to set GID to %lu: %s", gid,
_dbus_strerror (errno));
return FALSE;
}
if (setuid (uid) < 0)
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to set UID to %lu: %s", uid,
_dbus_strerror (errno));
return FALSE;
}
return TRUE;
}
/** Installs a UNIX signal handler
*
* @param sig the signal to handle
* @param handler the handler
*/
void
_dbus_set_signal_handler (int sig,
DBusSignalHandler handler)
{
struct sigaction act;
sigset_t empty_mask;
sigemptyset (&empty_mask);
act.sa_handler = handler;
act.sa_mask = empty_mask;
act.sa_flags = 0;
sigaction (sig, &act, NULL);
}
/**
* Removes a directory; Directory must be empty
*
* @param filename directory filename
* @param error initialized error object
* @returns #TRUE on success
*/
dbus_bool_t
_dbus_delete_directory (const DBusString *filename,
DBusError *error)
{
const char *filename_c;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
filename_c = _dbus_string_get_const_data (filename);
if (rmdir (filename_c) != 0)
{
dbus_set_error (error, DBUS_ERROR_FAILED,
"Failed to remove directory %s: %s\n",
filename_c, _dbus_strerror (errno));
return FALSE;
}
return TRUE;
}
/** Checks if a file exists
*
* @param file full path to the file
* @returns #TRUE if file exists
*/
dbus_bool_t
_dbus_file_exists (const char *file)
{
return (access (file, F_OK) == 0);
}
/** Checks if user is at the console
*
* @param username user to check
* @param error return location for errors
* @returns #TRUE is the user is at the consolei and there are no errors
*/
dbus_bool_t
_dbus_user_at_console (const char *username,
DBusError *error)
{
DBusString f;
dbus_bool_t result;
result = FALSE;
if (!_dbus_string_init (&f))
{
_DBUS_SET_OOM (error);
return FALSE;
}
if (!_dbus_string_append (&f, DBUS_CONSOLE_AUTH_DIR))
{
_DBUS_SET_OOM (error);
goto out;
}
if (!_dbus_string_append (&f, username))
{
_DBUS_SET_OOM (error);
goto out;
}
result = _dbus_file_exists (_dbus_string_get_const_data (&f));
out:
_dbus_string_free (&f);
return result;
}
/**
* Checks whether the filename is an absolute path
*
* @param filename the filename
* @returns #TRUE if an absolute path
*/
dbus_bool_t
_dbus_path_is_absolute (const DBusString *filename)
{
if (_dbus_string_get_length (filename) > 0)
return _dbus_string_get_byte (filename, 0) == '/';
else
return FALSE;
}
/**
* stat() wrapper.
*
* @param filename the filename to stat
* @param statbuf the stat info to fill in
* @param error return location for error
* @returns #FALSE if error was set
*/
dbus_bool_t
_dbus_stat (const DBusString *filename,
DBusStat *statbuf,
DBusError *error)
{
const char *filename_c;
struct stat sb;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
filename_c = _dbus_string_get_const_data (filename);
if (stat (filename_c, &sb) < 0)
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"%s", _dbus_strerror (errno));
return FALSE;
}
statbuf->mode = sb.st_mode;
statbuf->nlink = sb.st_nlink;
statbuf->uid = sb.st_uid;
statbuf->gid = sb.st_gid;
statbuf->size = sb.st_size;
statbuf->atime = sb.st_atime;
statbuf->mtime = sb.st_mtime;
statbuf->ctime = sb.st_ctime;
return TRUE;
}
/**
* Internals of directory iterator
*/
struct DBusDirIter
{
DIR *d; /**< The DIR* from opendir() */
};
/**
* Open a directory to iterate over.
*
* @param filename the directory name
* @param error exception return object or #NULL
* @returns new iterator, or #NULL on error
*/
DBusDirIter*
_dbus_directory_open (const DBusString *filename,
DBusError *error)
{
DIR *d;
DBusDirIter *iter;
const char *filename_c;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
filename_c = _dbus_string_get_const_data (filename);
d = opendir (filename_c);
if (d == NULL)
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to read directory \"%s\": %s",
filename_c,
_dbus_strerror (errno));
return NULL;
}
iter = dbus_new0 (DBusDirIter, 1);
if (iter == NULL)
{
closedir (d);
dbus_set_error (error, DBUS_ERROR_NO_MEMORY,
"Could not allocate memory for directory iterator");
return NULL;
}
iter->d = d;
return iter;
}
/* it is never safe to retrun a size smaller than sizeof(struct dirent)
* because the libc *could* try to access the whole structure
* (for instance it could try to memset it).
* it is also incorrect to return a size bigger than that, because
* the libc would never use it.
* The only correct and safe value this function can ever return is
* sizeof(struct dirent).
*/
static dbus_bool_t
dirent_buf_size(DIR * dirp, size_t *size)
{
*size = sizeof(struct dirent);
return TRUE;
}
/**
* Get next file in the directory. Will not return "." or ".." on
* UNIX. If an error occurs, the contents of "filename" are
* undefined. The error is never set if the function succeeds.
*
* @param iter the iterator
* @param filename string to be set to the next file in the dir
* @param error return location for error
* @returns #TRUE if filename was filled in with a new filename
*/
dbus_bool_t
_dbus_directory_get_next_file (DBusDirIter *iter,
DBusString *filename,
DBusError *error)
{
struct dirent *d, *ent;
size_t buf_size;
int err;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
if (!dirent_buf_size (iter->d, &buf_size))
{
dbus_set_error (error, DBUS_ERROR_FAILED,
"Can't calculate buffer size when reading directory");
return FALSE;
}
d = (struct dirent *)dbus_malloc (buf_size);
if (!d)
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY,
"No memory to read directory entry");
return FALSE;
}
again:
err = readdir_r (iter->d, d, &ent);
if (err || !ent)
{
if (err != 0)
dbus_set_error (error,
_dbus_error_from_errno (err),
"%s", _dbus_strerror (err));
dbus_free (d);
return FALSE;
}
else if (ent->d_name[0] == '.' &&
(ent->d_name[1] == '\0' ||
(ent->d_name[1] == '.' && ent->d_name[2] == '\0')))
goto again;
else
{
_dbus_string_set_length (filename, 0);
if (!_dbus_string_append (filename, ent->d_name))
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY,
"No memory to read directory entry");
dbus_free (d);
return FALSE;
}
else
{
dbus_free (d);
return TRUE;
}
}
}
/**
* Closes a directory iteration.
*/
void
_dbus_directory_close (DBusDirIter *iter)
{
closedir (iter->d);
dbus_free (iter);
}
static dbus_bool_t
fill_user_info_from_group (struct group *g,
DBusGroupInfo *info,
DBusError *error)
{
_dbus_assert (g->gr_name != NULL);
info->gid = g->gr_gid;
info->groupname = _dbus_strdup (g->gr_name);
/* info->members = dbus_strdupv (g->gr_mem) */
if (info->groupname == NULL)
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
return FALSE;
}
return TRUE;
}
static dbus_bool_t
fill_group_info (DBusGroupInfo *info,
dbus_gid_t gid,
const DBusString *groupname,
DBusError *error)
{
const char *group_c_str;
_dbus_assert (groupname != NULL || gid != DBUS_GID_UNSET);
_dbus_assert (groupname == NULL || gid == DBUS_GID_UNSET);
if (groupname)
group_c_str = _dbus_string_get_const_data (groupname);
else
group_c_str = NULL;
/* For now assuming that the getgrnam() and getgrgid() flavors
* always correspond to the pwnam flavors, if not we have
* to add more configure checks.
*/
#if defined (HAVE_POSIX_GETPWNAM_R) || defined (HAVE_NONPOSIX_GETPWNAM_R)
{
struct group *g;
int result;
char buf[1024];
struct group g_str;
g = NULL;
#ifdef HAVE_POSIX_GETPWNAM_R
if (group_c_str)
result = getgrnam_r (group_c_str, &g_str, buf, sizeof (buf),
&g);
else
result = getgrgid_r (gid, &g_str, buf, sizeof (buf),
&g);
#else
g = getgrnam_r (group_c_str, &g_str, buf, sizeof (buf));
result = 0;
#endif /* !HAVE_POSIX_GETPWNAM_R */
if (result == 0 && g == &g_str)
{
return fill_user_info_from_group (g, info, error);
}
else
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Group %s unknown or failed to look it up\n",
group_c_str ? group_c_str : "???");
return FALSE;
}
}
#else /* ! HAVE_GETPWNAM_R */
{
/* I guess we're screwed on thread safety here */
struct group *g;
g = getgrnam (group_c_str);
if (g != NULL)
{
return fill_user_info_from_group (g, info, error);
}
else
{
dbus_set_error (error, _dbus_error_from_errno (errno),
"Group %s unknown or failed to look it up\n",
group_c_str ? group_c_str : "???");
return FALSE;
}
}
#endif /* ! HAVE_GETPWNAM_R */
}
/**
* Initializes the given DBusGroupInfo struct
* with information about the given group name.
*
* @param info the group info struct
* @param groupname name of group
* @param error the error return
* @returns #FALSE if error is set
*/
dbus_bool_t
_dbus_group_info_fill (DBusGroupInfo *info,
const DBusString *groupname,
DBusError *error)
{
return fill_group_info (info, DBUS_GID_UNSET,
groupname, error);
}
/**
* Initializes the given DBusGroupInfo struct
* with information about the given group ID.
*
* @param info the group info struct
* @param gid group ID
* @param error the error return
* @returns #FALSE if error is set
*/
dbus_bool_t
_dbus_group_info_fill_gid (DBusGroupInfo *info,
dbus_gid_t gid,
DBusError *error)
{
return fill_group_info (info, gid, NULL, error);
}
/** @} */ /* End of DBusInternalsUtils functions */
/**
* @addtogroup DBusString
*
* @{
*/
/**
* Get the directory name from a complete filename
* @param filename the filename
* @param dirname string to append directory name to
* @returns #FALSE if no memory
*/
dbus_bool_t
_dbus_string_get_dirname (const DBusString *filename,
DBusString *dirname)
{
int sep;
_dbus_assert (filename != dirname);
_dbus_assert (filename != NULL);
_dbus_assert (dirname != NULL);
/* Ignore any separators on the end */
sep = _dbus_string_get_length (filename);
if (sep == 0)
return _dbus_string_append (dirname, "."); /* empty string passed in */
while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/')
--sep;
_dbus_assert (sep >= 0);
if (sep == 0)
return _dbus_string_append (dirname, "/");
/* Now find the previous separator */
_dbus_string_find_byte_backward (filename, sep, '/', &sep);
if (sep < 0)
return _dbus_string_append (dirname, ".");
/* skip multiple separators */
while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/')
--sep;
_dbus_assert (sep >= 0);
if (sep == 0 &&
_dbus_string_get_byte (filename, 0) == '/')
return _dbus_string_append (dirname, "/");
else
return _dbus_string_copy_len (filename, 0, sep - 0,
dirname, _dbus_string_get_length (dirname));
}
/** @} */ /* DBusString stuff */