libudev/libudev-util-private.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2003-2009 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 err;
  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         err = mkdir(p, 0755);
  54         if (err != 0 && errno == EEXIST)
  55                 if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  56                         err = 0;
  57         udev_selinux_resetfscreatecon(udev);
  58         return err;
  59 }
  60
  61 int util_delete_path(struct udev *udev, const char *path)
  62 {
  63         char p[UTIL_PATH_SIZE];
  64         char *pos;
  65         int retval;
  66
  67         if (path[0] == '/')
  68                 while(path[1] == '/')
  69                         path++;
  70         util_strscpy(p, sizeof(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 permissions of possible hard links will be removed too.
 100  */
 101 int util_unlink_secure(struct udev *udev, const char *filename)
 102 {
 103         int err;
 104
 105         chmod(filename, 0000);
 106         chown(filename, 0, 0);
 107         err = unlink(filename);
 108         if (errno == ENOENT)
 109                 err = 0;
 110         if (err)
 111                 err(udev, "unlink(%s) failed: %m\n", filename);
 112         return err;
 113 }
 114
 115 uid_t util_lookup_user(struct udev *udev, const char *user)
 116 {
 117         char *endptr;
 118         int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 119         char buf[buflen];
 120         struct passwd pwbuf;
 121         struct passwd *pw;
 122         uid_t uid;
 123
 124         if (strcmp(user, "root") == 0)
 125                 return 0;
 126         uid = strtoul(user, &endptr, 10);
 127         if (endptr[0] == '\0')
 128                 return uid;
 129
 130         errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
 131         if (pw != NULL)
 132                 return pw->pw_uid;
 133         if (errno == 0 || errno == ENOENT || errno == ESRCH)
 134                 err(udev, "specified user '%s' unknown\n", user);
 135         else
 136                 err(udev, "error resolving user '%s': %m\n", user);
 137         return 0;
 138 }
 139
 140 gid_t util_lookup_group(struct udev *udev, const char *group)
 141 {
 142         char *endptr;
 143         int buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
 144         char *buf;
 145         struct group grbuf;
 146         struct group *gr;
 147         gid_t gid = 0;
 148
 149         if (strcmp(group, "root") == 0)
 150                 return 0;
 151         gid = strtoul(group, &endptr, 10);
 152         if (endptr[0] == '\0')
 153                 return gid;
 154         buf = NULL;
 155         gid = 0;
 156         for (;;) {
 157                 char *newbuf;
 158
 159                 newbuf = realloc(buf, buflen);
 160                 if (!newbuf)
 161                         break;
 162                 buf = newbuf;
 163                 errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
 164                 if (gr != NULL) {
 165                         gid = gr->gr_gid;
 166                 } else if (errno == ERANGE) {
 167                         buflen *= 2;
 168                         continue;
 169                 } else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
 170                         err(udev, "specified group '%s' unknown\n", group);
 171                 } else {
 172                         err(udev, "error resolving group '%s': %m\n", group);
 173                 }
 174                 break;
 175         }
 176         free(buf);
 177         return gid;
 178 }
 179
 180 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 181 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 182                                char *result, size_t maxsize, int read_value)
 183 {
 184         char temp[UTIL_PATH_SIZE];
 185         char *subsys;
 186         char *sysname;
 187         struct udev_device *dev;
 188         char *attr;
 189
 190         if (string[0] != '[')
 191                 return -1;
 192
 193         util_strscpy(temp, sizeof(temp), string);
 194
 195         subsys = &temp[1];
 196
 197         sysname = strchr(subsys, '/');
 198         if (sysname == NULL)
 199                 return -1;
 200         sysname[0] = '\0';
 201         sysname = &sysname[1];
 202
 203         attr = strchr(sysname, ']');
 204         if (attr == NULL)
 205                 return -1;
 206         attr[0] = '\0';
 207         attr = &attr[1];
 208         if (attr[0] == '/')
 209                 attr = &attr[1];
 210         if (attr[0] == '\0')
 211                 attr = NULL;
 212
 213         if (read_value && attr == NULL)
 214                 return -1;
 215
 216         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 217         if (dev == NULL)
 218                 return -1;
 219
 220         if (read_value) {
 221                 const char *val;
 222
 223                 val = udev_device_get_sysattr_value(dev, attr);
 224                 if (val != NULL)
 225                         util_strscpy(result, maxsize, val);
 226                 else
 227                         result[0] = '\0';
 228                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 229         } else {
 230                 size_t l;
 231                 char *s;
 232
 233                 s = result;
 234                 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
 235                 if (attr != NULL)
 236                         util_strpcpyl(&s, l, "/", attr, NULL);
 237                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 238         }
 239         udev_device_unref(dev);
 240         return 0;
 241 }
 242
 243 int util_run_program(struct udev *udev, const char *command, char **envp,
 244                      char *result, size_t ressize, size_t *reslen)
 245 {
 246         int status;
 247         int outpipe[2] = {-1, -1};
 248         int errpipe[2] = {-1, -1};
 249         pid_t pid;
 250         char arg[UTIL_PATH_SIZE];
 251         char program[UTIL_PATH_SIZE];
 252         char *argv[(sizeof(arg) / 2) + 1];
 253         int devnull;
 254         int i;
 255         int err = 0;
 256
 257         info(udev, "'%s' started\n", command);
 258
 259         /* build argv from command */
 260         util_strscpy(arg, sizeof(arg), command);
 261         i = 0;
 262         if (strchr(arg, ' ') != NULL) {
 263                 char *pos = arg;
 264
 265                 while (pos != NULL && pos[0] != '\0') {
 266                         if (pos[0] == '\'') {
 267                                 /* do not separate quotes */
 268                                 pos++;
 269                                 argv[i] = strsep(&pos, "\'");
 270                                 while (pos != NULL && pos[0] == ' ')
 271                                         pos++;
 272                         } else {
 273                                 argv[i] = strsep(&pos, " ");
 274                         }
 275                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 276                         i++;
 277                 }
 278                 argv[i] = NULL;
 279         } else {
 280                 argv[0] = arg;
 281                 argv[1] = NULL;
 282         }
 283
 284         /* prepare pipes from child to parent */
 285         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 286                 if (pipe(outpipe) != 0) {
 287                         err(udev, "pipe failed: %m\n");
 288                         return -1;
 289                 }
 290         }
 291         if (udev_get_log_priority(udev) >= LOG_INFO) {
 292                 if (pipe(errpipe) != 0) {
 293                         err(udev, "pipe failed: %m\n");
 294                         return -1;
 295                 }
 296         }
 297
 298         /* allow programs in /lib/udev/ to be called without the path */
 299         if (argv[0][0] != '/') {
 300                 util_strscpyl(program, sizeof(program), LIBEXECDIR "/", argv[0], NULL);
 301                 argv[0] = program;
 302         }
 303
 304         pid = fork();
 305         switch(pid) {
 306         case 0:
 307                 /* child closes parent ends of pipes */
 308                 if (outpipe[READ_END] > 0)
 309                         close(outpipe[READ_END]);
 310                 if (errpipe[READ_END] > 0)
 311                         close(errpipe[READ_END]);
 312
 313                 /* discard child output or connect to pipe */
 314                 devnull = open("/dev/null", O_RDWR);
 315                 if (devnull > 0) {
 316                         dup2(devnull, STDIN_FILENO);
 317                         if (outpipe[WRITE_END] < 0)
 318                                 dup2(devnull, STDOUT_FILENO);
 319                         if (errpipe[WRITE_END] < 0)
 320                                 dup2(devnull, STDERR_FILENO);
 321                         close(devnull);
 322                 } else
 323                         err(udev, "open /dev/null failed: %m\n");
 324                 if (outpipe[WRITE_END] > 0) {
 325                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 326                         close(outpipe[WRITE_END]);
 327                 }
 328                 if (errpipe[WRITE_END] > 0) {
 329                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 330                         close(errpipe[WRITE_END]);
 331                 }
 332                 execve(argv[0], argv, envp);
 333                 if (errno == ENOENT || errno == ENOTDIR) {
 334                         /* may be on a filesystem which is not mounted right now */
 335                         info(udev, "program '%s' not found\n", argv[0]);
 336                 } else {
 337                         /* other problems */
 338                         err(udev, "exec of program '%s' failed\n", argv[0]);
 339                 }
 340                 _exit(1);
 341         case -1:
 342                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 343                 return -1;
 344         default:
 345                 /* read from child if requested */
 346                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 347                         ssize_t count;
 348                         size_t respos = 0;
 349
 350                         /* parent closes child ends of pipes */
 351                         if (outpipe[WRITE_END] > 0)
 352                                 close(outpipe[WRITE_END]);
 353                         if (errpipe[WRITE_END] > 0)
 354                                 close(errpipe[WRITE_END]);
 355
 356                         /* read child output */
 357                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 358                                 int fdcount;
 359                                 fd_set readfds;
 360
 361                                 FD_ZERO(&readfds);
 362                                 if (outpipe[READ_END] > 0)
 363                                         FD_SET(outpipe[READ_END], &readfds);
 364                                 if (errpipe[READ_END] > 0)
 365                                         FD_SET(errpipe[READ_END], &readfds);
 366                                 fdcount = select(MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 367                                 if (fdcount < 0) {
 368                                         if (errno == EINTR)
 369                                                 continue;
 370                                         err = -1;
 371                                         break;
 372                                 }
 373
 374                                 /* get stdout */
 375                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 376                                         char inbuf[1024];
 377                                         char *pos;
 378                                         char *line;
 379
 380                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 381                                         if (count <= 0) {
 382                                                 close(outpipe[READ_END]);
 383                                                 outpipe[READ_END] = -1;
 384                                                 if (count < 0) {
 385                                                         err(udev, "stdin read failed: %m\n");
 386                                                         err = -1;
 387                                                 }
 388                                                 continue;
 389                                         }
 390                                         inbuf[count] = '\0';
 391
 392                                         /* store result for rule processing */
 393                                         if (result) {
 394                                                 if (respos + count < ressize) {
 395                                                         memcpy(&result[respos], inbuf, count);
 396                                                         respos += count;
 397                                                 } else {
 398                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 399                                                         err = -1;
 400                                                 }
 401                                         }
 402                                         pos = inbuf;
 403                                         while ((line = strsep(&pos, "\n")))
 404                                                 if (pos || line[0] != '\0')
 405                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 406                                 }
 407
 408                                 /* get stderr */
 409                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 410                                         char errbuf[1024];
 411                                         char *pos;
 412                                         char *line;
 413
 414                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 415                                         if (count <= 0) {
 416                                                 close(errpipe[READ_END]);
 417                                                 errpipe[READ_END] = -1;
 418                                                 if (count < 0)
 419                                                         err(udev, "stderr read failed: %m\n");
 420                                                 continue;
 421                                         }
 422                                         errbuf[count] = '\0';
 423                                         pos = errbuf;
 424                                         while ((line = strsep(&pos, "\n")))
 425                                                 if (pos || line[0] != '\0')
 426                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 427                                 }
 428                         }
 429                         if (outpipe[READ_END] > 0)
 430                                 close(outpipe[READ_END]);
 431                         if (errpipe[READ_END] > 0)
 432                                 close(errpipe[READ_END]);
 433
 434                         /* return the childs stdout string */
 435                         if (result) {
 436                                 result[respos] = '\0';
 437                                 dbg(udev, "result='%s'\n", result);
 438                                 if (reslen)
 439                                         *reslen = respos;
 440                         }
 441                 }
 442                 waitpid(pid, &status, 0);
 443                 if (WIFEXITED(status)) {
 444                         info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
 445                         if (WEXITSTATUS(status) != 0)
 446                                 err = -1;
 447                 } else {
 448                         err(udev, "'%s' unexpected exit with status 0x%04x\n", command, status);
 449                         err = -1;
 450                 }
 451         }
 452         return err;
 453 }