udev/udev-util.c

   1 /*
   2  * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <stdlib.h>
  19 #include <stdio.h>
  20 #include <stddef.h>
  21 #include <unistd.h>
  22 #include <string.h>
  23 #include <fcntl.h>
  24 #include <errno.h>
  25 #include <ctype.h>
  26 #include <pwd.h>
  27 #include <grp.h>
  28 #include <sys/wait.h>
  29
  30 #include "udev.h"
  31
  32 int util_create_path(struct udev *udev, const char *path)
  33 {
  34         char p[UTIL_PATH_SIZE];
  35         char *pos;
  36         struct stat stats;
  37         int ret;
  38
  39         util_strlcpy(p, path, sizeof(p));
  40         pos = strrchr(p, '/');
  41         if (pos == p || pos == NULL)
  42                 return 0;
  43
  44         while (pos[-1] == '/')
  45                 pos--;
  46         pos[0] = '\0';
  47
  48         dbg(udev, "stat '%s'\n", p);
  49         if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  50                 return 0;
  51
  52         if (util_create_path(udev, p) != 0)
  53                 return -1;
  54
  55         dbg(udev, "mkdir '%s'\n", p);
  56         udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
  57         ret = mkdir(p, 0755);
  58         udev_selinux_resetfscreatecon(udev);
  59         if (ret == 0)
  60                 return 0;
  61
  62         if (errno == EEXIST)
  63                 if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  64                         return 0;
  65         return -1;
  66 }
  67
  68 int util_delete_path(struct udev *udev, const char *path)
  69 {
  70         char p[UTIL_PATH_SIZE];
  71         char *pos;
  72         int retval;
  73
  74         strcpy (p, path);
  75         pos = strrchr(p, '/');
  76         if (pos == p || pos == NULL)
  77                 return 0;
  78
  79         while (1) {
  80                 *pos = '\0';
  81                 pos = strrchr(p, '/');
  82
  83                 /* don't remove the last one */
  84                 if ((pos == p) || (pos == NULL))
  85                         break;
  86
  87                 /* remove if empty */
  88                 retval = rmdir(p);
  89                 if (errno == ENOENT)
  90                         retval = 0;
  91                 if (retval) {
  92                         if (errno == ENOTEMPTY)
  93                                 return 0;
  94                         err(udev, "rmdir(%s) failed: %m\n", p);
  95                         break;
  96                 }
  97                 dbg(udev, "removed '%s'\n", p);
  98         }
  99         return 0;
 100 }
 101
 102 /* Reset permissions on the device node, before unlinking it to make sure,
 103  * that permisions of possible hard links will be removed too.
 104  */
 105 int util_unlink_secure(struct udev *udev, const char *filename)
 106 {
 107         int retval;
 108
 109         retval = chown(filename, 0, 0);
 110         if (retval)
 111                 err(udev, "chown(%s, 0, 0) failed: %m\n", filename);
 112
 113         retval = chmod(filename, 0000);
 114         if (retval)
 115                 err(udev, "chmod(%s, 0000) failed: %m\n", filename);
 116
 117         retval = unlink(filename);
 118         if (errno == ENOENT)
 119                 retval = 0;
 120
 121         if (retval)
 122                 err(udev, "unlink(%s) failed: %m\n", filename);
 123
 124         return retval;
 125 }
 126
 127 uid_t util_lookup_user(struct udev *udev, const char *user)
 128 {
 129         struct passwd *pw;
 130         uid_t uid = 0;
 131
 132         if (strcmp(user, "root") == 0)
 133                 return 0;
 134         errno = 0;
 135         pw = getpwnam(user);
 136         if (pw == NULL) {
 137                 if (errno == 0 || errno == ENOENT || errno == ESRCH)
 138                         err(udev, "specified user '%s' unknown\n", user);
 139                 else
 140                         err(udev, "error resolving user '%s': %m\n", user);
 141         } else
 142                 uid = pw->pw_uid;
 143         return uid;
 144 }
 145
 146 extern gid_t util_lookup_group(struct udev *udev, const char *group)
 147 {
 148         struct group *gr;
 149         gid_t gid = 0;
 150
 151         if (strcmp(group, "root") == 0)
 152                 return 0;
 153         errno = 0;
 154         gr = getgrnam(group);
 155         if (gr == NULL) {
 156                 if (errno == 0 || errno == ENOENT || errno == ESRCH)
 157                         err(udev, "specified group '%s' unknown\n", group);
 158                 else
 159                         err(udev, "error resolving group '%s': %m\n", group);
 160         } else
 161                 gid = gr->gr_gid;
 162         return gid;
 163 }
 164
 165 int util_run_program(struct udev *udev, const char *command, char **envp,
 166                      char *result, size_t ressize, size_t *reslen)
 167 {
 168         int status;
 169         int outpipe[2] = {-1, -1};
 170         int errpipe[2] = {-1, -1};
 171         pid_t pid;
 172         char arg[UTIL_PATH_SIZE];
 173         char program[UTIL_PATH_SIZE];
 174         char *argv[(sizeof(arg) / 2) + 1];
 175         int devnull;
 176         int i;
 177         int err = 0;
 178
 179         /* build argv from command */
 180         util_strlcpy(arg, command, sizeof(arg));
 181         i = 0;
 182         if (strchr(arg, ' ') != NULL) {
 183                 char *pos = arg;
 184
 185                 while (pos != NULL && pos[0] != '\0') {
 186                         if (pos[0] == '\'') {
 187                                 /* do not separate quotes */
 188                                 pos++;
 189                                 argv[i] = strsep(&pos, "\'");
 190                                 while (pos != NULL && pos[0] == ' ')
 191                                         pos++;
 192                         } else {
 193                                 argv[i] = strsep(&pos, " ");
 194                         }
 195                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 196                         i++;
 197                 }
 198                 argv[i] = NULL;
 199         } else {
 200                 argv[0] = arg;
 201                 argv[1] = NULL;
 202         }
 203         info(udev, "'%s'\n", command);
 204
 205         /* prepare pipes from child to parent */
 206         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 207                 if (pipe(outpipe) != 0) {
 208                         err(udev, "pipe failed: %m\n");
 209                         return -1;
 210                 }
 211         }
 212         if (udev_get_log_priority(udev) >= LOG_INFO) {
 213                 if (pipe(errpipe) != 0) {
 214                         err(udev, "pipe failed: %m\n");
 215                         return -1;
 216                 }
 217         }
 218
 219         /* allow programs in /lib/udev/ to be called without the path */
 220         if (strchr(argv[0], '/') == NULL) {
 221                 util_strlcpy(program, UDEV_PREFIX "/lib/udev/", sizeof(program));
 222                 util_strlcat(program, argv[0], sizeof(program));
 223                 argv[0] = program;
 224         }
 225
 226         pid = fork();
 227         switch(pid) {
 228         case 0:
 229                 /* child closes parent ends of pipes */
 230                 if (outpipe[READ_END] > 0)
 231                         close(outpipe[READ_END]);
 232                 if (errpipe[READ_END] > 0)
 233                         close(errpipe[READ_END]);
 234
 235                 /* discard child output or connect to pipe */
 236                 devnull = open("/dev/null", O_RDWR);
 237                 if (devnull > 0) {
 238                         dup2(devnull, STDIN_FILENO);
 239                         if (outpipe[WRITE_END] < 0)
 240                                 dup2(devnull, STDOUT_FILENO);
 241                         if (errpipe[WRITE_END] < 0)
 242                                 dup2(devnull, STDERR_FILENO);
 243                         close(devnull);
 244                 } else
 245                         err(udev, "open /dev/null failed: %m\n");
 246                 if (outpipe[WRITE_END] > 0) {
 247                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 248                         close(outpipe[WRITE_END]);
 249                 }
 250                 if (errpipe[WRITE_END] > 0) {
 251                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 252                         close(errpipe[WRITE_END]);
 253                 }
 254                 execve(argv[0], argv, envp);
 255                 if (errno == ENOENT || errno == ENOTDIR) {
 256                         /* may be on a filesytem which is not mounted right now */
 257                         info(udev, "program '%s' not found\n", argv[0]);
 258                 } else {
 259                         /* other problems */
 260                         err(udev, "exec of program '%s' failed\n", argv[0]);
 261                 }
 262                 _exit(1);
 263         case -1:
 264                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 265                 return -1;
 266         default:
 267                 /* read from child if requested */
 268                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 269                         ssize_t count;
 270                         size_t respos = 0;
 271
 272                         /* parent closes child ends of pipes */
 273                         if (outpipe[WRITE_END] > 0)
 274                                 close(outpipe[WRITE_END]);
 275                         if (errpipe[WRITE_END] > 0)
 276                                 close(errpipe[WRITE_END]);
 277
 278                         /* read child output */
 279                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 280                                 int fdcount;
 281                                 fd_set readfds;
 282
 283                                 FD_ZERO(&readfds);
 284                                 if (outpipe[READ_END] > 0)
 285                                         FD_SET(outpipe[READ_END], &readfds);
 286                                 if (errpipe[READ_END] > 0)
 287                                         FD_SET(errpipe[READ_END], &readfds);
 288                                 fdcount = select(UDEV_MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 289                                 if (fdcount < 0) {
 290                                         if (errno == EINTR)
 291                                                 continue;
 292                                         err = -1;
 293                                         break;
 294                                 }
 295
 296                                 /* get stdout */
 297                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 298                                         char inbuf[1024];
 299                                         char *pos;
 300                                         char *line;
 301
 302                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 303                                         if (count <= 0) {
 304                                                 close(outpipe[READ_END]);
 305                                                 outpipe[READ_END] = -1;
 306                                                 if (count < 0) {
 307                                                         err(udev, "stdin read failed: %m\n");
 308                                                         err = -1;
 309                                                 }
 310                                                 continue;
 311                                         }
 312                                         inbuf[count] = '\0';
 313
 314                                         /* store result for rule processing */
 315                                         if (result) {
 316                                                 if (respos + count < ressize) {
 317                                                         memcpy(&result[respos], inbuf, count);
 318                                                         respos += count;
 319                                                 } else {
 320                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 321                                                         err = -1;
 322                                                 }
 323                                         }
 324                                         pos = inbuf;
 325                                         while ((line = strsep(&pos, "\n")))
 326                                                 if (pos || line[0] != '\0')
 327                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 328                                 }
 329
 330                                 /* get stderr */
 331                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 332                                         char errbuf[1024];
 333                                         char *pos;
 334                                         char *line;
 335
 336                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 337                                         if (count <= 0) {
 338                                                 close(errpipe[READ_END]);
 339                                                 errpipe[READ_END] = -1;
 340                                                 if (count < 0)
 341                                                         err(udev, "stderr read failed: %m\n");
 342                                                 continue;
 343                                         }
 344                                         errbuf[count] = '\0';
 345                                         pos = errbuf;
 346                                         while ((line = strsep(&pos, "\n")))
 347                                                 if (pos || line[0] != '\0')
 348                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 349                                 }
 350                         }
 351                         if (outpipe[READ_END] > 0)
 352                                 close(outpipe[READ_END]);
 353                         if (errpipe[READ_END] > 0)
 354                                 close(errpipe[READ_END]);
 355
 356                         /* return the childs stdout string */
 357                         if (result) {
 358                                 result[respos] = '\0';
 359                                 dbg(udev, "result='%s'\n", result);
 360                                 if (reslen)
 361                                         *reslen = respos;
 362                         }
 363                 }
 364                 waitpid(pid, &status, 0);
 365                 if (WIFEXITED(status)) {
 366                         info(udev, "'%s' returned with status %i\n", argv[0], WEXITSTATUS(status));
 367                         if (WEXITSTATUS(status) != 0)
 368                                 err = -1;
 369                 } else {
 370                         err(udev, "'%s' abnormal exit\n", argv[0]);
 371                         err = -1;
 372                 }
 373         }
 374         return err;
 375 }