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dbus-sysdeps-util.c

00001 /* -*- mode: C; c-file-style: "gnu" -*- */
00002 /* dbus-sysdeps-util.c Would be in dbus-sysdeps.c, but not used in libdbus
00003  * 
00004  * Copyright (C) 2002, 2003, 2004, 2005  Red Hat, Inc.
00005  * Copyright (C) 2003 CodeFactory AB
00006  *
00007  * Licensed under the Academic Free License version 2.1
00008  * 
00009  * This program is free software; you can redistribute it and/or modify
00010  * it under the terms of the GNU General Public License as published by
00011  * the Free Software Foundation; either version 2 of the License, or
00012  * (at your option) any later version.
00013  *
00014  * This program is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00017  * GNU General Public License for more details.
00018  * 
00019  * You should have received a copy of the GNU General Public License
00020  * along with this program; if not, write to the Free Software
00021  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00022  *
00023  */
00024 #include "dbus-sysdeps.h"
00025 #include "dbus-internals.h"
00026 #include "dbus-protocol.h"
00027 #include "dbus-string.h"
00028 #define DBUS_USERDB_INCLUDES_PRIVATE 1
00029 #include "dbus-userdb.h"
00030 #include "dbus-test.h"
00031 
00032 #include <sys/types.h>
00033 #include <stdlib.h>
00034 #include <string.h>
00035 #include <signal.h>
00036 #include <unistd.h>
00037 #include <stdio.h>
00038 #include <errno.h>
00039 #include <fcntl.h>
00040 #include <sys/stat.h>
00041 #include <grp.h>
00042 #include <sys/socket.h>
00043 #include <dirent.h>
00044 #include <sys/un.h>
00045 
00046 #ifndef O_BINARY
00047 #define O_BINARY 0
00048 #endif
00049 
00063 dbus_bool_t
00064 _dbus_become_daemon (const DBusString *pidfile,
00065                      int               print_pid_fd,
00066                      DBusError        *error)
00067 {
00068   const char *s;
00069   pid_t child_pid;
00070   int dev_null_fd;
00071 
00072   _dbus_verbose ("Becoming a daemon...\n");
00073 
00074   _dbus_verbose ("chdir to /\n");
00075   if (chdir ("/") < 0)
00076     {
00077       dbus_set_error (error, DBUS_ERROR_FAILED,
00078                       "Could not chdir() to root directory");
00079       return FALSE;
00080     }
00081 
00082   _dbus_verbose ("forking...\n");
00083   switch ((child_pid = fork ()))
00084     {
00085     case -1:
00086       _dbus_verbose ("fork failed\n");
00087       dbus_set_error (error, _dbus_error_from_errno (errno),
00088                       "Failed to fork daemon: %s", _dbus_strerror (errno));
00089       return FALSE;
00090       break;
00091 
00092     case 0:
00093       _dbus_verbose ("in child, closing std file descriptors\n");
00094 
00095       /* silently ignore failures here, if someone
00096        * doesn't have /dev/null we may as well try
00097        * to continue anyhow
00098        */
00099       
00100       dev_null_fd = open ("/dev/null", O_RDWR);
00101       if (dev_null_fd >= 0)
00102         {
00103           dup2 (dev_null_fd, 0);
00104           dup2 (dev_null_fd, 1);
00105           
00106           s = _dbus_getenv ("DBUS_DEBUG_OUTPUT");
00107           if (s == NULL || *s == '\0')
00108             dup2 (dev_null_fd, 2);
00109           else
00110             _dbus_verbose ("keeping stderr open due to DBUS_DEBUG_OUTPUT\n");
00111         }
00112 
00113       /* Get a predictable umask */
00114       _dbus_verbose ("setting umask\n");
00115       umask (022);
00116       break;
00117 
00118     default:
00119       if (pidfile)
00120         {
00121           _dbus_verbose ("parent writing pid file\n");
00122           if (!_dbus_write_pid_file (pidfile,
00123                                      child_pid,
00124                                      error))
00125             {
00126               _dbus_verbose ("pid file write failed, killing child\n");
00127               kill (child_pid, SIGTERM);
00128               return FALSE;
00129             }
00130         }
00131 
00132       /* Write PID if requested */
00133       if (print_pid_fd >= 0)
00134         {
00135           DBusString pid;
00136           int bytes;
00137           
00138           if (!_dbus_string_init (&pid))
00139             {
00140               _DBUS_SET_OOM (error);
00141               kill (child_pid, SIGTERM);
00142               return FALSE;
00143             }
00144           
00145           if (!_dbus_string_append_int (&pid, child_pid) ||
00146               !_dbus_string_append (&pid, "\n"))
00147             {
00148               _dbus_string_free (&pid);
00149               _DBUS_SET_OOM (error);
00150               kill (child_pid, SIGTERM);
00151               return FALSE;
00152             }
00153           
00154           bytes = _dbus_string_get_length (&pid);
00155           if (_dbus_write (print_pid_fd, &pid, 0, bytes) != bytes)
00156             {
00157               dbus_set_error (error, DBUS_ERROR_FAILED,
00158                               "Printing message bus PID: %s\n",
00159                               _dbus_strerror (errno));
00160               _dbus_string_free (&pid);
00161               kill (child_pid, SIGTERM);
00162               return FALSE;
00163             }
00164           
00165           _dbus_string_free (&pid);
00166         }
00167       _dbus_verbose ("parent exiting\n");
00168       _exit (0);
00169       break;
00170     }
00171 
00172   _dbus_verbose ("calling setsid()\n");
00173   if (setsid () == -1)
00174     _dbus_assert_not_reached ("setsid() failed");
00175   
00176   return TRUE;
00177 }
00178 
00179 
00188 dbus_bool_t
00189 _dbus_write_pid_file (const DBusString *filename,
00190                       unsigned long     pid,
00191                       DBusError        *error)
00192 {
00193   const char *cfilename;
00194   int fd;
00195   FILE *f;
00196 
00197   cfilename = _dbus_string_get_const_data (filename);
00198   
00199   fd = open (cfilename, O_WRONLY|O_CREAT|O_EXCL|O_BINARY, 0644);
00200   
00201   if (fd < 0)
00202     {
00203       dbus_set_error (error, _dbus_error_from_errno (errno),
00204                       "Failed to open \"%s\": %s", cfilename,
00205                       _dbus_strerror (errno));
00206       return FALSE;
00207     }
00208 
00209   if ((f = fdopen (fd, "w")) == NULL)
00210     {
00211       dbus_set_error (error, _dbus_error_from_errno (errno),
00212                       "Failed to fdopen fd %d: %s", fd, _dbus_strerror (errno));
00213       close (fd);
00214       return FALSE;
00215     }
00216   
00217   if (fprintf (f, "%lu\n", pid) < 0)
00218     {
00219       dbus_set_error (error, _dbus_error_from_errno (errno),
00220                       "Failed to write to \"%s\": %s", cfilename,
00221                       _dbus_strerror (errno));
00222       return FALSE;
00223     }
00224 
00225   if (fclose (f) == EOF)
00226     {
00227       dbus_set_error (error, _dbus_error_from_errno (errno),
00228                       "Failed to close \"%s\": %s", cfilename,
00229                       _dbus_strerror (errno));
00230       return FALSE;
00231     }
00232   
00233   return TRUE;
00234 }
00235 
00236 
00245 dbus_bool_t
00246 _dbus_change_identity  (dbus_uid_t     uid,
00247                         dbus_gid_t     gid,
00248                         DBusError     *error)
00249 {
00250   /* setgroups() only works if we are a privileged process,
00251    * so we don't return error on failure; the only possible
00252    * failure is that we don't have perms to do it.
00253    * FIXME not sure this is right, maybe if setuid()
00254    * is going to work then setgroups() should also work.
00255    */
00256   if (setgroups (0, NULL) < 0)
00257     _dbus_warn ("Failed to drop supplementary groups: %s\n",
00258                 _dbus_strerror (errno));
00259   
00260   /* Set GID first, or the setuid may remove our permission
00261    * to change the GID
00262    */
00263   if (setgid (gid) < 0)
00264     {
00265       dbus_set_error (error, _dbus_error_from_errno (errno),
00266                       "Failed to set GID to %lu: %s", gid,
00267                       _dbus_strerror (errno));
00268       return FALSE;
00269     }
00270   
00271   if (setuid (uid) < 0)
00272     {
00273       dbus_set_error (error, _dbus_error_from_errno (errno),
00274                       "Failed to set UID to %lu: %s", uid,
00275                       _dbus_strerror (errno));
00276       return FALSE;
00277     }
00278   
00279   return TRUE;
00280 }
00281 
00287 void
00288 _dbus_set_signal_handler (int               sig,
00289                           DBusSignalHandler handler)
00290 {
00291   struct sigaction act;
00292   sigset_t empty_mask;
00293   
00294   sigemptyset (&empty_mask);
00295   act.sa_handler = handler;
00296   act.sa_mask    = empty_mask;
00297   act.sa_flags   = 0;
00298   sigaction (sig,  &act, 0);
00299 }
00300 
00301 
00309 dbus_bool_t
00310 _dbus_delete_directory (const DBusString *filename,
00311                         DBusError        *error)
00312 {
00313   const char *filename_c;
00314   
00315   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00316 
00317   filename_c = _dbus_string_get_const_data (filename);
00318 
00319   if (rmdir (filename_c) != 0)
00320     {
00321       dbus_set_error (error, DBUS_ERROR_FAILED,
00322                       "Failed to remove directory %s: %s\n",
00323                       filename_c, _dbus_strerror (errno));
00324       return FALSE;
00325     }
00326   
00327   return TRUE;
00328 }
00329 
00335 dbus_bool_t 
00336 _dbus_file_exists (const char *file)
00337 {
00338   return (access (file, F_OK) == 0);
00339 }
00340 
00347 dbus_bool_t 
00348 _dbus_user_at_console (const char *username,
00349                        DBusError  *error)
00350 {
00351 
00352   DBusString f;
00353   dbus_bool_t result;
00354 
00355   result = FALSE;
00356   if (!_dbus_string_init (&f))
00357     {
00358       _DBUS_SET_OOM (error);
00359       return FALSE;
00360     }
00361 
00362   if (!_dbus_string_append (&f, DBUS_CONSOLE_AUTH_DIR))
00363     {
00364       _DBUS_SET_OOM (error);
00365       goto out;
00366     }
00367 
00368 
00369   if (!_dbus_string_append (&f, username))
00370     {
00371       _DBUS_SET_OOM (error);
00372       goto out;
00373     }
00374 
00375   result = _dbus_file_exists (_dbus_string_get_const_data (&f));
00376 
00377  out:
00378   _dbus_string_free (&f);
00379 
00380   return result;
00381 }
00382 
00383 
00390 dbus_bool_t
00391 _dbus_path_is_absolute (const DBusString *filename)
00392 {
00393   if (_dbus_string_get_length (filename) > 0)
00394     return _dbus_string_get_byte (filename, 0) == '/';
00395   else
00396     return FALSE;
00397 }
00398 
00407 dbus_bool_t
00408 _dbus_stat (const DBusString *filename,
00409             DBusStat         *statbuf,
00410             DBusError        *error)
00411 {
00412   const char *filename_c;
00413   struct stat sb;
00414 
00415   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00416   
00417   filename_c = _dbus_string_get_const_data (filename);
00418 
00419   if (stat (filename_c, &sb) < 0)
00420     {
00421       dbus_set_error (error, _dbus_error_from_errno (errno),
00422                       "%s", _dbus_strerror (errno));
00423       return FALSE;
00424     }
00425 
00426   statbuf->mode = sb.st_mode;
00427   statbuf->nlink = sb.st_nlink;
00428   statbuf->uid = sb.st_uid;
00429   statbuf->gid = sb.st_gid;
00430   statbuf->size = sb.st_size;
00431   statbuf->atime = sb.st_atime;
00432   statbuf->mtime = sb.st_mtime;
00433   statbuf->ctime = sb.st_ctime;
00434 
00435   return TRUE;
00436 }
00437 
00438 
00442 struct DBusDirIter
00443 {
00444   DIR *d; 
00446 };
00447 
00455 DBusDirIter*
00456 _dbus_directory_open (const DBusString *filename,
00457                       DBusError        *error)
00458 {
00459   DIR *d;
00460   DBusDirIter *iter;
00461   const char *filename_c;
00462 
00463   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00464   
00465   filename_c = _dbus_string_get_const_data (filename);
00466 
00467   d = opendir (filename_c);
00468   if (d == NULL)
00469     {
00470       dbus_set_error (error, _dbus_error_from_errno (errno),
00471                       "Failed to read directory \"%s\": %s",
00472                       filename_c,
00473                       _dbus_strerror (errno));
00474       return NULL;
00475     }
00476   iter = dbus_new0 (DBusDirIter, 1);
00477   if (iter == NULL)
00478     {
00479       closedir (d);
00480       dbus_set_error (error, DBUS_ERROR_NO_MEMORY,
00481                       "Could not allocate memory for directory iterator");
00482       return NULL;
00483     }
00484 
00485   iter->d = d;
00486 
00487   return iter;
00488 }
00489 
00503 dbus_bool_t
00504 _dbus_directory_get_next_file (DBusDirIter      *iter,
00505                                DBusString       *filename,
00506                                DBusError        *error)
00507 {
00508   struct dirent *ent;
00509 
00510   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00511   
00512  again:
00513   errno = 0;
00514   ent = readdir (iter->d);
00515   if (ent == NULL)
00516     {
00517       if (errno != 0)
00518         dbus_set_error (error,
00519                         _dbus_error_from_errno (errno),
00520                         "%s", _dbus_strerror (errno));
00521       return FALSE;
00522     }
00523   else if (ent->d_name[0] == '.' &&
00524            (ent->d_name[1] == '\0' ||
00525             (ent->d_name[1] == '.' && ent->d_name[2] == '\0')))
00526     goto again;
00527   else
00528     {
00529       _dbus_string_set_length (filename, 0);
00530       if (!_dbus_string_append (filename, ent->d_name))
00531         {
00532           dbus_set_error (error, DBUS_ERROR_NO_MEMORY,
00533                           "No memory to read directory entry");
00534           return FALSE;
00535         }
00536       else
00537         return TRUE;
00538     }
00539 }
00540 
00544 void
00545 _dbus_directory_close (DBusDirIter *iter)
00546 {
00547   closedir (iter->d);
00548   dbus_free (iter);
00549 }
00550 
00551 static dbus_bool_t
00552 fill_user_info_from_group (struct group  *g,
00553                            DBusGroupInfo *info,
00554                            DBusError     *error)
00555 {
00556   _dbus_assert (g->gr_name != NULL);
00557   
00558   info->gid = g->gr_gid;
00559   info->groupname = _dbus_strdup (g->gr_name);
00560 
00561   /* info->members = dbus_strdupv (g->gr_mem) */
00562   
00563   if (info->groupname == NULL)
00564     {
00565       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00566       return FALSE;
00567     }
00568 
00569   return TRUE;
00570 }
00571 
00572 static dbus_bool_t
00573 fill_group_info (DBusGroupInfo    *info,
00574                  dbus_gid_t        gid,
00575                  const DBusString *groupname,
00576                  DBusError        *error)
00577 {
00578   const char *group_c_str;
00579 
00580   _dbus_assert (groupname != NULL || gid != DBUS_GID_UNSET);
00581   _dbus_assert (groupname == NULL || gid == DBUS_GID_UNSET);
00582 
00583   if (groupname)
00584     group_c_str = _dbus_string_get_const_data (groupname);
00585   else
00586     group_c_str = NULL;
00587   
00588   /* For now assuming that the getgrnam() and getgrgid() flavors
00589    * always correspond to the pwnam flavors, if not we have
00590    * to add more configure checks.
00591    */
00592   
00593 #if defined (HAVE_POSIX_GETPWNAM_R) || defined (HAVE_NONPOSIX_GETPWNAM_R)
00594   {
00595     struct group *g;
00596     int result;
00597     char buf[1024];
00598     struct group g_str;
00599 
00600     g = NULL;
00601 #ifdef HAVE_POSIX_GETPWNAM_R
00602 
00603     if (group_c_str)
00604       result = getgrnam_r (group_c_str, &g_str, buf, sizeof (buf),
00605                            &g);
00606     else
00607       result = getgrgid_r (gid, &g_str, buf, sizeof (buf),
00608                            &g);
00609 #else
00610     g = getgrnam_r (group_c_str, &g_str, buf, sizeof (buf));
00611     result = 0;
00612 #endif /* !HAVE_POSIX_GETPWNAM_R */
00613     if (result == 0 && g == &g_str)
00614       {
00615         return fill_user_info_from_group (g, info, error);
00616       }
00617     else
00618       {
00619         dbus_set_error (error, _dbus_error_from_errno (errno),
00620                         "Group %s unknown or failed to look it up\n",
00621                         group_c_str ? group_c_str : "???");
00622         return FALSE;
00623       }
00624   }
00625 #else /* ! HAVE_GETPWNAM_R */
00626   {
00627     /* I guess we're screwed on thread safety here */
00628     struct group *g;
00629 
00630     g = getgrnam (group_c_str);
00631 
00632     if (g != NULL)
00633       {
00634         return fill_user_info_from_group (g, info, error);
00635       }
00636     else
00637       {
00638         dbus_set_error (error, _dbus_error_from_errno (errno),
00639                         "Group %s unknown or failed to look it up\n",
00640                         group_c_str ? group_c_str : "???");
00641         return FALSE;
00642       }
00643   }
00644 #endif  /* ! HAVE_GETPWNAM_R */
00645 }
00646 
00656 dbus_bool_t
00657 _dbus_group_info_fill (DBusGroupInfo    *info,
00658                        const DBusString *groupname,
00659                        DBusError        *error)
00660 {
00661   return fill_group_info (info, DBUS_GID_UNSET,
00662                           groupname, error);
00663 
00664 }
00665 
00675 dbus_bool_t
00676 _dbus_group_info_fill_gid (DBusGroupInfo *info,
00677                            dbus_gid_t     gid,
00678                            DBusError     *error)
00679 {
00680   return fill_group_info (info, gid, NULL, error);
00681 }
00682 
00688 void
00689 _dbus_group_info_free (DBusGroupInfo    *info)
00690 {
00691   dbus_free (info->groupname);
00692 }
00693  /* End of DBusInternalsUtils functions */
00695 
00707 dbus_bool_t
00708 _dbus_string_get_dirname  (const DBusString *filename,
00709                            DBusString       *dirname)
00710 {
00711   int sep;
00712   
00713   _dbus_assert (filename != dirname);
00714   _dbus_assert (filename != NULL);
00715   _dbus_assert (dirname != NULL);
00716 
00717   /* Ignore any separators on the end */
00718   sep = _dbus_string_get_length (filename);
00719   if (sep == 0)
00720     return _dbus_string_append (dirname, "."); /* empty string passed in */
00721     
00722   while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/')
00723     --sep;
00724 
00725   _dbus_assert (sep >= 0);
00726   
00727   if (sep == 0)
00728     return _dbus_string_append (dirname, "/");
00729   
00730   /* Now find the previous separator */
00731   _dbus_string_find_byte_backward (filename, sep, '/', &sep);
00732   if (sep < 0)
00733     return _dbus_string_append (dirname, ".");
00734   
00735   /* skip multiple separators */
00736   while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/')
00737     --sep;
00738 
00739   _dbus_assert (sep >= 0);
00740   
00741   if (sep == 0 &&
00742       _dbus_string_get_byte (filename, 0) == '/')
00743     return _dbus_string_append (dirname, "/");
00744   else
00745     return _dbus_string_copy_len (filename, 0, sep - 0,
00746                                   dirname, _dbus_string_get_length (dirname));
00747 } /* DBusString stuff */
00749 
00750 
00751 #ifdef DBUS_BUILD_TESTS
00752 #include <stdlib.h>
00753 static void
00754 check_dirname (const char *filename,
00755                const char *dirname)
00756 {
00757   DBusString f, d;
00758   
00759   _dbus_string_init_const (&f, filename);
00760 
00761   if (!_dbus_string_init (&d))
00762     _dbus_assert_not_reached ("no memory");
00763 
00764   if (!_dbus_string_get_dirname (&f, &d))
00765     _dbus_assert_not_reached ("no memory");
00766 
00767   if (!_dbus_string_equal_c_str (&d, dirname))
00768     {
00769       _dbus_warn ("For filename \"%s\" got dirname \"%s\" and expected \"%s\"\n",
00770                   filename,
00771                   _dbus_string_get_const_data (&d),
00772                   dirname);
00773       exit (1);
00774     }
00775 
00776   _dbus_string_free (&d);
00777 }
00778 
00779 static void
00780 check_path_absolute (const char *path,
00781                      dbus_bool_t expected)
00782 {
00783   DBusString p;
00784 
00785   _dbus_string_init_const (&p, path);
00786 
00787   if (_dbus_path_is_absolute (&p) != expected)
00788     {
00789       _dbus_warn ("For path \"%s\" expected absolute = %d got %d\n",
00790                   path, expected, _dbus_path_is_absolute (&p));
00791       exit (1);
00792     }
00793 }
00794 
00800 dbus_bool_t
00801 _dbus_sysdeps_test (void)
00802 {
00803   DBusString str;
00804   double val;
00805   int pos;
00806   
00807   check_dirname ("foo", ".");
00808   check_dirname ("foo/bar", "foo");
00809   check_dirname ("foo//bar", "foo");
00810   check_dirname ("foo///bar", "foo");
00811   check_dirname ("foo/bar/", "foo");
00812   check_dirname ("foo//bar/", "foo");
00813   check_dirname ("foo///bar/", "foo");
00814   check_dirname ("foo/bar//", "foo");
00815   check_dirname ("foo//bar////", "foo");
00816   check_dirname ("foo///bar///////", "foo");
00817   check_dirname ("/foo", "/");
00818   check_dirname ("
00819   check_dirname ("/foo/bar", "/foo");
00820   check_dirname ("/foo//bar", "/foo");
00821   check_dirname ("/foo///bar", "/foo");
00822   check_dirname ("/", "/");
00823   check_dirname ("
00824   check_dirname ("", ".");  
00825 
00826 
00827   _dbus_string_init_const (&str, "3.5");
00828   if (!_dbus_string_parse_double (&str,
00829                                   0, &val, &pos))
00830     {
00831       _dbus_warn ("Failed to parse double");
00832       exit (1);
00833     }
00834   if (ABS(3.5 - val) > 1e-6)
00835     {
00836       _dbus_warn ("Failed to parse 3.5 correctly, got: %f", val);
00837       exit (1);
00838     }
00839   if (pos != 3)
00840     {
00841       _dbus_warn ("_dbus_string_parse_double of \"3.5\" returned wrong position %d", pos);
00842       exit (1);
00843     }
00844 
00845   _dbus_string_init_const (&str, "0xff");
00846   if (!_dbus_string_parse_double (&str,
00847                                   0, &val, &pos))
00848     {
00849       _dbus_warn ("Failed to parse double");
00850       exit (1);
00851     }
00852   if (ABS (0xff - val) > 1e-6)
00853     {
00854       _dbus_warn ("Failed to parse 0xff correctly, got: %f\n", val);
00855       exit (1);
00856     }
00857   if (pos != 4)
00858     {
00859       _dbus_warn ("_dbus_string_parse_double of \"0xff\" returned wrong position %d", pos);
00860       exit (1);
00861     }
00862   
00863   check_path_absolute ("/", TRUE);
00864   check_path_absolute ("/foo", TRUE);
00865   check_path_absolute ("", FALSE);
00866   check_path_absolute ("foo", FALSE);
00867   check_path_absolute ("foo/bar", FALSE);
00868   
00869   return TRUE;
00870 }
00871 #endif /* DBUS_BUILD_TESTS */

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