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 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         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                 buf = realloc(buf, buflen);
 158                 if (!buf)
 159                         break;
 160                 errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
 161                 if (gr != NULL) {
 162                         gid = gr->gr_gid;
 163                 } else if (errno == ERANGE) {
 164                         buflen *= 2;
 165                         continue;
 166                 } else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
 167                         err(udev, "specified group '%s' unknown\n", group);
 168                 } else {
 169                         err(udev, "error resolving group '%s': %m\n", group);
 170                 }
 171                 break;
 172         }
 173         free(buf);
 174         return gid;
 175 }
 176
 177 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 178 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 179                                char *result, size_t maxsize, int read_value)
 180 {
 181         char temp[UTIL_PATH_SIZE];
 182         char *subsys;
 183         char *sysname;
 184         struct udev_device *dev;
 185         char *attr;
 186
 187         if (string[0] != '[')
 188                 return -1;
 189
 190         util_strscpy(temp, sizeof(temp), string);
 191
 192         subsys = &temp[1];
 193
 194         sysname = strchr(subsys, '/');
 195         if (sysname == NULL)
 196                 return -1;
 197         sysname[0] = '\0';
 198         sysname = &sysname[1];
 199
 200         attr = strchr(sysname, ']');
 201         if (attr == NULL)
 202                 return -1;
 203         attr[0] = '\0';
 204         attr = &attr[1];
 205         if (attr[0] == '/')
 206                 attr = &attr[1];
 207         if (attr[0] == '\0')
 208                 attr = NULL;
 209
 210         if (read_value && attr == NULL)
 211                 return -1;
 212
 213         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 214         if (dev == NULL)
 215                 return -1;
 216
 217         if (read_value) {
 218                 const char *val;
 219
 220                 val = udev_device_get_sysattr_value(dev, attr);
 221                 if (val != NULL)
 222                         util_strscpy(result, maxsize, val);
 223                 else
 224                         result[0] = '\0';
 225                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 226         } else {
 227                 size_t l;
 228                 char *s;
 229
 230                 s = result;
 231                 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
 232                 if (attr != NULL)
 233                         util_strpcpyl(&s, l, "/", attr, NULL);
 234                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 235         }
 236         udev_device_unref(dev);
 237         return 0;
 238 }
 239
 240 int util_run_program(struct udev *udev, const char *command, char **envp,
 241                      char *result, size_t ressize, size_t *reslen)
 242 {
 243         int status;
 244         int outpipe[2] = {-1, -1};
 245         int errpipe[2] = {-1, -1};
 246         pid_t pid;
 247         char arg[UTIL_PATH_SIZE];
 248         char program[UTIL_PATH_SIZE];
 249         char *argv[(sizeof(arg) / 2) + 1];
 250         int devnull;
 251         int i;
 252         int err = 0;
 253
 254         info(udev, "'%s' started\n", command);
 255
 256         /* build argv from command */
 257         util_strscpy(arg, sizeof(arg), command);
 258         i = 0;
 259         if (strchr(arg, ' ') != NULL) {
 260                 char *pos = arg;
 261
 262                 while (pos != NULL && pos[0] != '\0') {
 263                         if (pos[0] == '\'') {
 264                                 /* do not separate quotes */
 265                                 pos++;
 266                                 argv[i] = strsep(&pos, "\'");
 267                                 while (pos != NULL && pos[0] == ' ')
 268                                         pos++;
 269                         } else {
 270                                 argv[i] = strsep(&pos, " ");
 271                         }
 272                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 273                         i++;
 274                 }
 275                 argv[i] = NULL;
 276         } else {
 277                 argv[0] = arg;
 278                 argv[1] = NULL;
 279         }
 280
 281         /* prepare pipes from child to parent */
 282         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 283                 if (pipe(outpipe) != 0) {
 284                         err(udev, "pipe failed: %m\n");
 285                         return -1;
 286                 }
 287         }
 288         if (udev_get_log_priority(udev) >= LOG_INFO) {
 289                 if (pipe(errpipe) != 0) {
 290                         err(udev, "pipe failed: %m\n");
 291                         return -1;
 292                 }
 293         }
 294
 295         /* allow programs in /lib/udev/ to be called without the path */
 296         if (argv[0][0] != '/') {
 297                 util_strscpyl(program, sizeof(program), LIBEXECDIR "/", argv[0], NULL);
 298                 argv[0] = program;
 299         }
 300
 301         pid = fork();
 302         switch(pid) {
 303         case 0:
 304                 /* child closes parent ends of pipes */
 305                 if (outpipe[READ_END] > 0)
 306                         close(outpipe[READ_END]);
 307                 if (errpipe[READ_END] > 0)
 308                         close(errpipe[READ_END]);
 309
 310                 /* discard child output or connect to pipe */
 311                 devnull = open("/dev/null", O_RDWR);
 312                 if (devnull > 0) {
 313                         dup2(devnull, STDIN_FILENO);
 314                         if (outpipe[WRITE_END] < 0)
 315                                 dup2(devnull, STDOUT_FILENO);
 316                         if (errpipe[WRITE_END] < 0)
 317                                 dup2(devnull, STDERR_FILENO);
 318                         close(devnull);
 319                 } else
 320                         err(udev, "open /dev/null failed: %m\n");
 321                 if (outpipe[WRITE_END] > 0) {
 322                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 323                         close(outpipe[WRITE_END]);
 324                 }
 325                 if (errpipe[WRITE_END] > 0) {
 326                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 327                         close(errpipe[WRITE_END]);
 328                 }
 329                 execve(argv[0], argv, envp);
 330                 if (errno == ENOENT || errno == ENOTDIR) {
 331                         /* may be on a filesystem which is not mounted right now */
 332                         info(udev, "program '%s' not found\n", argv[0]);
 333                 } else {
 334                         /* other problems */
 335                         err(udev, "exec of program '%s' failed\n", argv[0]);
 336                 }
 337                 _exit(1);
 338         case -1:
 339                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 340                 return -1;
 341         default:
 342                 /* read from child if requested */
 343                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 344                         ssize_t count;
 345                         size_t respos = 0;
 346
 347                         /* parent closes child ends of pipes */
 348                         if (outpipe[WRITE_END] > 0)
 349                                 close(outpipe[WRITE_END]);
 350                         if (errpipe[WRITE_END] > 0)
 351                                 close(errpipe[WRITE_END]);
 352
 353                         /* read child output */
 354                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 355                                 int fdcount;
 356                                 fd_set readfds;
 357
 358                                 FD_ZERO(&readfds);
 359                                 if (outpipe[READ_END] > 0)
 360                                         FD_SET(outpipe[READ_END], &readfds);
 361                                 if (errpipe[READ_END] > 0)
 362                                         FD_SET(errpipe[READ_END], &readfds);
 363                                 fdcount = select(MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 364                                 if (fdcount < 0) {
 365                                         if (errno == EINTR)
 366                                                 continue;
 367                                         err = -1;
 368                                         break;
 369                                 }
 370
 371                                 /* get stdout */
 372                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 373                                         char inbuf[1024];
 374                                         char *pos;
 375                                         char *line;
 376
 377                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 378                                         if (count <= 0) {
 379                                                 close(outpipe[READ_END]);
 380                                                 outpipe[READ_END] = -1;
 381                                                 if (count < 0) {
 382                                                         err(udev, "stdin read failed: %m\n");
 383                                                         err = -1;
 384                                                 }
 385                                                 continue;
 386                                         }
 387                                         inbuf[count] = '\0';
 388
 389                                         /* store result for rule processing */
 390                                         if (result) {
 391                                                 if (respos + count < ressize) {
 392                                                         memcpy(&result[respos], inbuf, count);
 393                                                         respos += count;
 394                                                 } else {
 395                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 396                                                         err = -1;
 397                                                 }
 398                                         }
 399                                         pos = inbuf;
 400                                         while ((line = strsep(&pos, "\n")))
 401                                                 if (pos || line[0] != '\0')
 402                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 403                                 }
 404
 405                                 /* get stderr */
 406                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 407                                         char errbuf[1024];
 408                                         char *pos;
 409                                         char *line;
 410
 411                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 412                                         if (count <= 0) {
 413                                                 close(errpipe[READ_END]);
 414                                                 errpipe[READ_END] = -1;
 415                                                 if (count < 0)
 416                                                         err(udev, "stderr read failed: %m\n");
 417                                                 continue;
 418                                         }
 419                                         errbuf[count] = '\0';
 420                                         pos = errbuf;
 421                                         while ((line = strsep(&pos, "\n")))
 422                                                 if (pos || line[0] != '\0')
 423                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 424                                 }
 425                         }
 426                         if (outpipe[READ_END] > 0)
 427                                 close(outpipe[READ_END]);
 428                         if (errpipe[READ_END] > 0)
 429                                 close(errpipe[READ_END]);
 430
 431                         /* return the childs stdout string */
 432                         if (result) {
 433                                 result[respos] = '\0';
 434                                 dbg(udev, "result='%s'\n", result);
 435                                 if (reslen)
 436                                         *reslen = respos;
 437                         }
 438                 }
 439                 waitpid(pid, &status, 0);
 440                 if (WIFEXITED(status)) {
 441                         info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
 442                         if (WEXITSTATUS(status) != 0)
 443                                 err = -1;
 444                 } else {
 445                         err(udev, "'%s' unexpected exit with status 0x%04x\n", command, status);
 446                         err = -1;
 447                 }
 448         }
 449         return err;
 450 }