libudev/libudev-util-private.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2004-2009 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <stddef.h>
  15 #include <unistd.h>
  16 #include <string.h>
  17 #include <fcntl.h>
  18 #include <errno.h>
  19 #include <ctype.h>
  20 #include <pwd.h>
  21 #include <grp.h>
  22 #include <sys/wait.h>
  23 #include <sys/param.h>
  24
  25 #include "libudev.h"
  26 #include "libudev-private.h"
  27
  28 int util_create_path(struct udev *udev, const char *path)
  29 {
  30         char p[UTIL_PATH_SIZE];
  31         char *pos;
  32         struct stat stats;
  33         int ret;
  34
  35         util_strscpy(p, sizeof(p), path);
  36         pos = strrchr(p, '/');
  37         if (pos == p || pos == NULL)
  38                 return 0;
  39
  40         while (pos[-1] == '/')
  41                 pos--;
  42         pos[0] = '\0';
  43
  44         dbg(udev, "stat '%s'\n", p);
  45         if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  46                 return 0;
  47
  48         if (util_create_path(udev, p) != 0)
  49                 return -1;
  50
  51         dbg(udev, "mkdir '%s'\n", p);
  52         udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
  53         ret = mkdir(p, 0755);
  54         udev_selinux_resetfscreatecon(udev);
  55         if (ret == 0)
  56                 return 0;
  57
  58         if (errno == EEXIST)
  59                 if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  60                         return 0;
  61         return -1;
  62 }
  63
  64 int util_delete_path(struct udev *udev, const char *path)
  65 {
  66         char p[UTIL_PATH_SIZE];
  67         char *pos;
  68         int retval;
  69
  70         strcpy (p, path);
  71         pos = strrchr(p, '/');
  72         if (pos == p || pos == NULL)
  73                 return 0;
  74
  75         while (1) {
  76                 *pos = '\0';
  77                 pos = strrchr(p, '/');
  78
  79                 /* don't remove the last one */
  80                 if ((pos == p) || (pos == NULL))
  81                         break;
  82
  83                 /* remove if empty */
  84                 retval = rmdir(p);
  85                 if (errno == ENOENT)
  86                         retval = 0;
  87                 if (retval) {
  88                         if (errno == ENOTEMPTY)
  89                                 return 0;
  90                         err(udev, "rmdir(%s) failed: %m\n", p);
  91                         break;
  92                 }
  93                 dbg(udev, "removed '%s'\n", p);
  94         }
  95         return 0;
  96 }
  97
  98 /* Reset permissions on the device node, before unlinking it to make sure,
  99  * that permisions of possible hard links will be removed too.
 100  */
 101 int util_unlink_secure(struct udev *udev, const char *filename)
 102 {
 103         int retval;
 104
 105         retval = chown(filename, 0, 0);
 106         if (retval)
 107                 err(udev, "chown(%s, 0, 0) failed: %m\n", filename);
 108
 109         retval = chmod(filename, 0000);
 110         if (retval)
 111                 err(udev, "chmod(%s, 0000) failed: %m\n", filename);
 112
 113         retval = unlink(filename);
 114         if (errno == ENOENT)
 115                 retval = 0;
 116
 117         if (retval)
 118                 err(udev, "unlink(%s) failed: %m\n", filename);
 119
 120         return retval;
 121 }
 122
 123 uid_t util_lookup_user(struct udev *udev, const char *user)
 124 {
 125         char *endptr;
 126         int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 127         char buf[buflen];
 128         struct passwd pwbuf;
 129         struct passwd *pw;
 130         uid_t uid;
 131
 132         if (strcmp(user, "root") == 0)
 133                 return 0;
 134         uid = strtoul(user, &endptr, 10);
 135         if (endptr[0] == '\0')
 136                 return uid;
 137
 138         errno = 0;
 139         getpwnam_r(user, &pwbuf, buf, buflen, &pw);
 140         if (pw != NULL)
 141                 return pw->pw_uid;
 142         if (errno == 0 || errno == ENOENT || errno == ESRCH)
 143                 err(udev, "specified user '%s' unknown\n", user);
 144         else
 145                 err(udev, "error resolving user '%s': %m\n", user);
 146         return 0;
 147 }
 148
 149 gid_t util_lookup_group(struct udev *udev, const char *group)
 150 {
 151         char *endptr;
 152         int buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
 153         char buf[buflen];
 154         struct group grbuf;
 155         struct group *gr;
 156         gid_t gid = 0;
 157
 158         if (strcmp(group, "root") == 0)
 159                 return 0;
 160         gid = strtoul(group, &endptr, 10);
 161         if (endptr[0] == '\0')
 162                 return gid;
 163
 164         errno = 0;
 165         getgrnam_r(group, &grbuf, buf, buflen, &gr);
 166         if (gr != NULL)
 167                 return gr->gr_gid;
 168         if (errno == 0 || errno == ENOENT || errno == ESRCH)
 169                 err(udev, "specified group '%s' unknown\n", group);
 170         else
 171                 err(udev, "error resolving group '%s': %m\n", group);
 172         return 0;
 173 }
 174
 175 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 176 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 177                                char *result, size_t maxsize, int read_value)
 178 {
 179         char temp[UTIL_PATH_SIZE];
 180         char *subsys;
 181         char *sysname;
 182         struct udev_device *dev;
 183         char *attr;
 184
 185         if (string[0] != '[')
 186                 return -1;
 187
 188         util_strscpy(temp, sizeof(temp), string);
 189
 190         subsys = &temp[1];
 191
 192         sysname = strchr(subsys, '/');
 193         if (sysname == NULL)
 194                 return -1;
 195         sysname[0] = '\0';
 196         sysname = &sysname[1];
 197
 198         attr = strchr(sysname, ']');
 199         if (attr == NULL)
 200                 return -1;
 201         attr[0] = '\0';
 202         attr = &attr[1];
 203         if (attr[0] == '/')
 204                 attr = &attr[1];
 205         if (attr[0] == '\0')
 206                 attr = NULL;
 207
 208         if (read_value && attr == NULL)
 209                 return -1;
 210
 211         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 212         if (dev == NULL)
 213                 return -1;
 214
 215         if (read_value) {
 216                 const char *val;
 217
 218                 val = udev_device_get_sysattr_value(dev, attr);
 219                 if (val != NULL)
 220                         util_strscpy(result, maxsize, val);
 221                 else
 222                         result[0] = '\0';
 223                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 224         } else {
 225                 size_t l;
 226                 char *s;
 227
 228                 s = result;
 229                 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
 230                 if (attr != NULL)
 231                         util_strpcpyl(&s, l, "/", attr, NULL);
 232                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 233         }
 234         udev_device_unref(dev);
 235         return 0;
 236 }
 237
 238 int util_run_program(struct udev *udev, const char *command, char **envp,
 239                      char *result, size_t ressize, size_t *reslen)
 240 {
 241         int status;
 242         int outpipe[2] = {-1, -1};
 243         int errpipe[2] = {-1, -1};
 244         pid_t pid;
 245         char arg[UTIL_PATH_SIZE];
 246         char program[UTIL_PATH_SIZE];
 247         char *argv[(sizeof(arg) / 2) + 1];
 248         int devnull;
 249         int i;
 250         int err = 0;
 251
 252         info(udev, "'%s' started\n", command);
 253
 254         /* build argv from command */
 255         util_strscpy(arg, sizeof(arg), command);
 256         i = 0;
 257         if (strchr(arg, ' ') != NULL) {
 258                 char *pos = arg;
 259
 260                 while (pos != NULL && pos[0] != '\0') {
 261                         if (pos[0] == '\'') {
 262                                 /* do not separate quotes */
 263                                 pos++;
 264                                 argv[i] = strsep(&pos, "\'");
 265                                 while (pos != NULL && pos[0] == ' ')
 266                                         pos++;
 267                         } else {
 268                                 argv[i] = strsep(&pos, " ");
 269                         }
 270                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 271                         i++;
 272                 }
 273                 argv[i] = NULL;
 274         } else {
 275                 argv[0] = arg;
 276                 argv[1] = NULL;
 277         }
 278
 279         /* prepare pipes from child to parent */
 280         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 281                 if (pipe(outpipe) != 0) {
 282                         err(udev, "pipe failed: %m\n");
 283                         return -1;
 284                 }
 285         }
 286         if (udev_get_log_priority(udev) >= LOG_INFO) {
 287                 if (pipe(errpipe) != 0) {
 288                         err(udev, "pipe failed: %m\n");
 289                         return -1;
 290                 }
 291         }
 292
 293         /* allow programs in /lib/udev/ to be called without the path */
 294         if (argv[0][0] != '/') {
 295                 util_strscpyl(program, sizeof(program), LIBEXECDIR "/", argv[0], NULL);
 296                 argv[0] = program;
 297         }
 298
 299         pid = fork();
 300         switch(pid) {
 301         case 0:
 302                 /* child closes parent ends of pipes */
 303                 if (outpipe[READ_END] > 0)
 304                         close(outpipe[READ_END]);
 305                 if (errpipe[READ_END] > 0)
 306                         close(errpipe[READ_END]);
 307
 308                 /* discard child output or connect to pipe */
 309                 devnull = open("/dev/null", O_RDWR);
 310                 if (devnull > 0) {
 311                         dup2(devnull, STDIN_FILENO);
 312                         if (outpipe[WRITE_END] < 0)
 313                                 dup2(devnull, STDOUT_FILENO);
 314                         if (errpipe[WRITE_END] < 0)
 315                                 dup2(devnull, STDERR_FILENO);
 316                         close(devnull);
 317                 } else
 318                         err(udev, "open /dev/null failed: %m\n");
 319                 if (outpipe[WRITE_END] > 0) {
 320                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 321                         close(outpipe[WRITE_END]);
 322                 }
 323                 if (errpipe[WRITE_END] > 0) {
 324                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 325                         close(errpipe[WRITE_END]);
 326                 }
 327                 execve(argv[0], argv, envp);
 328                 if (errno == ENOENT || errno == ENOTDIR) {
 329                         /* may be on a filesytem which is not mounted right now */
 330                         info(udev, "program '%s' not found\n", argv[0]);
 331                 } else {
 332                         /* other problems */
 333                         err(udev, "exec of program '%s' failed\n", argv[0]);
 334                 }
 335                 _exit(1);
 336         case -1:
 337                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 338                 return -1;
 339         default:
 340                 /* read from child if requested */
 341                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 342                         ssize_t count;
 343                         size_t respos = 0;
 344
 345                         /* parent closes child ends of pipes */
 346                         if (outpipe[WRITE_END] > 0)
 347                                 close(outpipe[WRITE_END]);
 348                         if (errpipe[WRITE_END] > 0)
 349                                 close(errpipe[WRITE_END]);
 350
 351                         /* read child output */
 352                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 353                                 int fdcount;
 354                                 fd_set readfds;
 355
 356                                 FD_ZERO(&readfds);
 357                                 if (outpipe[READ_END] > 0)
 358                                         FD_SET(outpipe[READ_END], &readfds);
 359                                 if (errpipe[READ_END] > 0)
 360                                         FD_SET(errpipe[READ_END], &readfds);
 361                                 fdcount = select(MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 362                                 if (fdcount < 0) {
 363                                         if (errno == EINTR)
 364                                                 continue;
 365                                         err = -1;
 366                                         break;
 367                                 }
 368
 369                                 /* get stdout */
 370                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 371                                         char inbuf[1024];
 372                                         char *pos;
 373                                         char *line;
 374
 375                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 376                                         if (count <= 0) {
 377                                                 close(outpipe[READ_END]);
 378                                                 outpipe[READ_END] = -1;
 379                                                 if (count < 0) {
 380                                                         err(udev, "stdin read failed: %m\n");
 381                                                         err = -1;
 382                                                 }
 383                                                 continue;
 384                                         }
 385                                         inbuf[count] = '\0';
 386
 387                                         /* store result for rule processing */
 388                                         if (result) {
 389                                                 if (respos + count < ressize) {
 390                                                         memcpy(&result[respos], inbuf, count);
 391                                                         respos += count;
 392                                                 } else {
 393                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 394                                                         err = -1;
 395                                                 }
 396                                         }
 397                                         pos = inbuf;
 398                                         while ((line = strsep(&pos, "\n")))
 399                                                 if (pos || line[0] != '\0')
 400                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 401                                 }
 402
 403                                 /* get stderr */
 404                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 405                                         char errbuf[1024];
 406                                         char *pos;
 407                                         char *line;
 408
 409                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 410                                         if (count <= 0) {
 411                                                 close(errpipe[READ_END]);
 412                                                 errpipe[READ_END] = -1;
 413                                                 if (count < 0)
 414                                                         err(udev, "stderr read failed: %m\n");
 415                                                 continue;
 416                                         }
 417                                         errbuf[count] = '\0';
 418                                         pos = errbuf;
 419                                         while ((line = strsep(&pos, "\n")))
 420                                                 if (pos || line[0] != '\0')
 421                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 422                                 }
 423                         }
 424                         if (outpipe[READ_END] > 0)
 425                                 close(outpipe[READ_END]);
 426                         if (errpipe[READ_END] > 0)
 427                                 close(errpipe[READ_END]);
 428
 429                         /* return the childs stdout string */
 430                         if (result) {
 431                                 result[respos] = '\0';
 432                                 dbg(udev, "result='%s'\n", result);
 433                                 if (reslen)
 434                                         *reslen = respos;
 435                         }
 436                 }
 437                 waitpid(pid, &status, 0);
 438                 if (WIFEXITED(status)) {
 439                         info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
 440                         if (WEXITSTATUS(status) != 0)
 441                                 err = -1;
 442                 } else {
 443                         err(udev, "'%s' unexpected exit with status 0x%04x\n", command, status);
 444                         err = -1;
 445                 }
 446         }
 447         return err;
 448 }