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         errno = 0;
 133         pw = getpwnam(user);
 134         if (pw == NULL) {
 135                 if (errno == 0 || errno == ENOENT || errno == ESRCH)
 136                         err(udev, "specified user '%s' unknown\n", user);
 137                 else
 138                         err(udev, "error resolving user '%s': %m\n", user);
 139         } else
 140                 uid = pw->pw_uid;
 141
 142         return uid;
 143 }
 144
 145 extern gid_t util_lookup_group(struct udev *udev, const char *group)
 146 {
 147         struct group *gr;
 148         gid_t gid = 0;
 149
 150         errno = 0;
 151         gr = getgrnam(group);
 152         if (gr == NULL) {
 153                 if (errno == 0 || errno == ENOENT || errno == ESRCH)
 154                         err(udev, "specified group '%s' unknown\n", group);
 155                 else
 156                         err(udev, "error resolving group '%s': %m\n", group);
 157         } else
 158                 gid = gr->gr_gid;
 159
 160         return gid;
 161 }
 162
 163 int util_run_program(struct udev *udev, const char *command, char **envp,
 164                      char *result, size_t ressize, size_t *reslen)
 165 {
 166         int status;
 167         int outpipe[2] = {-1, -1};
 168         int errpipe[2] = {-1, -1};
 169         pid_t pid;
 170         char arg[UTIL_PATH_SIZE];
 171         char program[UTIL_PATH_SIZE];
 172         char *argv[(sizeof(arg) / 2) + 1];
 173         int devnull;
 174         int i;
 175         int err = 0;
 176
 177         /* build argv from command */
 178         util_strlcpy(arg, command, sizeof(arg));
 179         i = 0;
 180         if (strchr(arg, ' ') != NULL) {
 181                 char *pos = arg;
 182
 183                 while (pos != NULL && pos[0] != '\0') {
 184                         if (pos[0] == '\'') {
 185                                 /* do not separate quotes */
 186                                 pos++;
 187                                 argv[i] = strsep(&pos, "\'");
 188                                 while (pos != NULL && pos[0] == ' ')
 189                                         pos++;
 190                         } else {
 191                                 argv[i] = strsep(&pos, " ");
 192                         }
 193                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 194                         i++;
 195                 }
 196                 argv[i] = NULL;
 197         } else {
 198                 argv[0] = arg;
 199                 argv[1] = NULL;
 200         }
 201         info(udev, "'%s'\n", command);
 202
 203         /* prepare pipes from child to parent */
 204         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 205                 if (pipe(outpipe) != 0) {
 206                         err(udev, "pipe failed: %m\n");
 207                         return -1;
 208                 }
 209         }
 210         if (udev_get_log_priority(udev) >= LOG_INFO) {
 211                 if (pipe(errpipe) != 0) {
 212                         err(udev, "pipe failed: %m\n");
 213                         return -1;
 214                 }
 215         }
 216
 217         /* allow programs in /lib/udev/ to be called without the path */
 218         if (strchr(argv[0], '/') == NULL) {
 219                 util_strlcpy(program, UDEV_PREFIX "/lib/udev/", sizeof(program));
 220                 util_strlcat(program, argv[0], sizeof(program));
 221                 argv[0] = program;
 222         }
 223
 224         pid = fork();
 225         switch(pid) {
 226         case 0:
 227                 /* child closes parent ends of pipes */
 228                 if (outpipe[READ_END] > 0)
 229                         close(outpipe[READ_END]);
 230                 if (errpipe[READ_END] > 0)
 231                         close(errpipe[READ_END]);
 232
 233                 /* discard child output or connect to pipe */
 234                 devnull = open("/dev/null", O_RDWR);
 235                 if (devnull > 0) {
 236                         dup2(devnull, STDIN_FILENO);
 237                         if (outpipe[WRITE_END] < 0)
 238                                 dup2(devnull, STDOUT_FILENO);
 239                         if (errpipe[WRITE_END] < 0)
 240                                 dup2(devnull, STDERR_FILENO);
 241                         close(devnull);
 242                 } else
 243                         err(udev, "open /dev/null failed: %m\n");
 244                 if (outpipe[WRITE_END] > 0) {
 245                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 246                         close(outpipe[WRITE_END]);
 247                 }
 248                 if (errpipe[WRITE_END] > 0) {
 249                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 250                         close(errpipe[WRITE_END]);
 251                 }
 252                 execve(argv[0], argv, envp);
 253                 if (errno == ENOENT || errno == ENOTDIR) {
 254                         /* may be on a filesytem which is not mounted right now */
 255                         info(udev, "program '%s' not found\n", argv[0]);
 256                 } else {
 257                         /* other problems */
 258                         err(udev, "exec of program '%s' failed\n", argv[0]);
 259                 }
 260                 _exit(1);
 261         case -1:
 262                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 263                 return -1;
 264         default:
 265                 /* read from child if requested */
 266                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 267                         ssize_t count;
 268                         size_t respos = 0;
 269
 270                         /* parent closes child ends of pipes */
 271                         if (outpipe[WRITE_END] > 0)
 272                                 close(outpipe[WRITE_END]);
 273                         if (errpipe[WRITE_END] > 0)
 274                                 close(errpipe[WRITE_END]);
 275
 276                         /* read child output */
 277                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 278                                 int fdcount;
 279                                 fd_set readfds;
 280
 281                                 FD_ZERO(&readfds);
 282                                 if (outpipe[READ_END] > 0)
 283                                         FD_SET(outpipe[READ_END], &readfds);
 284                                 if (errpipe[READ_END] > 0)
 285                                         FD_SET(errpipe[READ_END], &readfds);
 286                                 fdcount = select(UDEV_MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 287                                 if (fdcount < 0) {
 288                                         if (errno == EINTR)
 289                                                 continue;
 290                                         err = -1;
 291                                         break;
 292                                 }
 293
 294                                 /* get stdout */
 295                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 296                                         char inbuf[1024];
 297                                         char *pos;
 298                                         char *line;
 299
 300                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 301                                         if (count <= 0) {
 302                                                 close(outpipe[READ_END]);
 303                                                 outpipe[READ_END] = -1;
 304                                                 if (count < 0) {
 305                                                         err(udev, "stdin read failed: %m\n");
 306                                                         err = -1;
 307                                                 }
 308                                                 continue;
 309                                         }
 310                                         inbuf[count] = '\0';
 311
 312                                         /* store result for rule processing */
 313                                         if (result) {
 314                                                 if (respos + count < ressize) {
 315                                                         memcpy(&result[respos], inbuf, count);
 316                                                         respos += count;
 317                                                 } else {
 318                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 319                                                         err = -1;
 320                                                 }
 321                                         }
 322                                         pos = inbuf;
 323                                         while ((line = strsep(&pos, "\n")))
 324                                                 if (pos || line[0] != '\0')
 325                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 326                                 }
 327
 328                                 /* get stderr */
 329                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 330                                         char errbuf[1024];
 331                                         char *pos;
 332                                         char *line;
 333
 334                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 335                                         if (count <= 0) {
 336                                                 close(errpipe[READ_END]);
 337                                                 errpipe[READ_END] = -1;
 338                                                 if (count < 0)
 339                                                         err(udev, "stderr read failed: %m\n");
 340                                                 continue;
 341                                         }
 342                                         errbuf[count] = '\0';
 343                                         pos = errbuf;
 344                                         while ((line = strsep(&pos, "\n")))
 345                                                 if (pos || line[0] != '\0')
 346                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 347                                 }
 348                         }
 349                         if (outpipe[READ_END] > 0)
 350                                 close(outpipe[READ_END]);
 351                         if (errpipe[READ_END] > 0)
 352                                 close(errpipe[READ_END]);
 353
 354                         /* return the childs stdout string */
 355                         if (result) {
 356                                 result[respos] = '\0';
 357                                 dbg(udev, "result='%s'\n", result);
 358                                 if (reslen)
 359                                         *reslen = respos;
 360                         }
 361                 }
 362                 waitpid(pid, &status, 0);
 363                 if (WIFEXITED(status)) {
 364                         info(udev, "'%s' returned with status %i\n", argv[0], WEXITSTATUS(status));
 365                         if (WEXITSTATUS(status) != 0)
 366                                 err = -1;
 367                 } else {
 368                         err(udev, "'%s' abnormal exit\n", argv[0]);
 369                         err = -1;
 370                 }
 371         }
 372         return err;
 373 }