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Sourcecode: alsa-utils version File versions

init_utils_run.c

/*
 * Copyright (C) 2004-2005 Kay Sievers <kay.sievers@vrfy.org>
 *
 *    This program is free software; you can redistribute it and/or modify it
 *    under the terms of the GNU General Public License as published by the
 *    Free Software Foundation version 2 of the License.
 * 
 *    This program is distributed in the hope that it will be useful, but
 *    WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    General Public License for more details.
 * 
 *    You should have received a copy of the GNU General Public License along
 *    with this program; if not, write to the Free Software Foundation, Inc.,
 *    51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 */

#define MY_MAX(a,b) ((a) > (b) ? (a) : (b))

#define READ_END  0
#define WRITE_END 1

static
int run_program1(struct space *space,
               const char *command0, char *result,
             size_t ressize, size_t *reslen, int log);

static
int run_program0(struct space *space,
               const char *command0, char *result,
             size_t ressize, size_t *reslen, int log)
{
      int retval = 0;
      int status;
      int outpipe[2] = {-1, -1};
      int errpipe[2] = {-1, -1};
      pid_t pid;
      char arg[PATH_SIZE];
      char program[PATH_SIZE];
      char *argv[(sizeof(arg) / 2) + 1];
      int devnull;
      int i;

      /* build argv from comand */
      strlcpy(arg, command0, sizeof(arg));
      i = 0;
      if (strchr(arg, ' ') != NULL) {
            char *pos = arg;

            while (pos != NULL) {
                  if (pos[0] == '\'') {
                        /* don't separate if in apostrophes */
                        pos++;
                        argv[i] = strsep(&pos, "\'");
                        while (pos != NULL && pos[0] == ' ')
                              pos++;
                  } else {
                        argv[i] = strsep(&pos, " ");
                  }
                  dbg("arg[%i] '%s'", i, argv[i]);
                  i++;
            }
            argv[i] = NULL;
      } else {
            argv[0] = arg;
            argv[1] = NULL;
      }
      info("'%s'", command0);

      /* prepare pipes from child to parent */
      if (result || log) {
            if (pipe(outpipe) != 0) {
                  Perror(space, "pipe failed: %s", strerror(errno));
                  return -1;
            }
      }
      if (log) {
            if (pipe(errpipe) != 0) {
                  Perror(space, "pipe failed: %s", strerror(errno));
                  return -1;
            }
      }

      /* allow programs in /lib/alsa called without the path */
      if (strchr(argv[0], '/') == NULL) {
            strlcpy(program, "/lib/alsa/", sizeof(program));
            strlcat(program, argv[0], sizeof(program));
            argv[0] = program;
      }

      pid = fork();
      switch(pid) {
      case 0:
            /* child closes parent ends of pipes */
            if (outpipe[READ_END] > 0)
                  close(outpipe[READ_END]);
            if (errpipe[READ_END] > 0)
                  close(errpipe[READ_END]);

            /* discard child output or connect to pipe */
            devnull = open("/dev/null", O_RDWR);
            if (devnull > 0) {
                  dup2(devnull, STDIN_FILENO);
                  if (outpipe[WRITE_END] < 0)
                        dup2(devnull, STDOUT_FILENO);
                  if (errpipe[WRITE_END] < 0)
                        dup2(devnull, STDERR_FILENO);
                  close(devnull);
            } else
                  Perror(space, "open /dev/null failed: %s", strerror(errno));
            if (outpipe[WRITE_END] > 0) {
                  dup2(outpipe[WRITE_END], STDOUT_FILENO);
                  close(outpipe[WRITE_END]);
            }
            if (errpipe[WRITE_END] > 0) {
                  dup2(errpipe[WRITE_END], STDERR_FILENO);
                  close(errpipe[WRITE_END]);
            }
            execv(argv[0], argv);

            /* we should never reach this */
            Perror(space, "exec of program '%s' failed", argv[0]);
            _exit(1);
      case -1:
            Perror(space, "fork of '%s' failed: %s", argv[0], strerror(errno));
            return -1;
      default:
            /* read from child if requested */
            if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
                  ssize_t count;
                  size_t respos = 0;

                  /* parent closes child ends of pipes */
                  if (outpipe[WRITE_END] > 0)
                        close(outpipe[WRITE_END]);
                  if (errpipe[WRITE_END] > 0)
                        close(errpipe[WRITE_END]);

                  /* read child output */
                  while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
                        int fdcount;
                        fd_set readfds;

                        FD_ZERO(&readfds);
                        if (outpipe[READ_END] > 0)
                              FD_SET(outpipe[READ_END], &readfds);
                        if (errpipe[READ_END] > 0)
                              FD_SET(errpipe[READ_END], &readfds);
                        fdcount = select(MY_MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
                        if (fdcount < 0) {
                              if (errno == EINTR)
                                    continue;
                              retval = -1;
                              break;
                        }

                        /* get stdout */
                        if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
                              char inbuf[1024];
                              char *pos;
                              char *line;

                              count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
                              if (count <= 0) {
                                    close(outpipe[READ_END]);
                                    outpipe[READ_END] = -1;
                                    if (count < 0) {
                                          Perror(space, "stdin read failed: %s", strerror(errno));
                                          retval = -1;
                                    }
                                    continue;
                              }
                              inbuf[count] = '\0';

                              /* store result for rule processing */
                              if (result) {
                                    if (respos + count < ressize) {
                                          memcpy(&result[respos], inbuf, count);
                                          respos += count;
                                    } else {
                                          Perror(space, "ressize %ld too short", (long)ressize);
                                          retval = -1;
                                    }
                              }
                              pos = inbuf;
                              while ((line = strsep(&pos, "\n")))
                                    if (pos || line[0] != '\0')
                                          info("'%s' (stdout) '%s'", argv[0], line);
                        }

                        /* get stderr */
                        if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
                              char errbuf[1024];
                              char *pos;
                              char *line;

                              count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
                              if (count <= 0) {
                                    close(errpipe[READ_END]);
                                    errpipe[READ_END] = -1;
                                    if (count < 0)
                                          Perror(space, "stderr read failed: %s", strerror(errno));
                                    continue;
                              }
                              errbuf[count] = '\0';
                              pos = errbuf;
                              while ((line = strsep(&pos, "\n")))
                                    if (pos || line[0] != '\0')
                                          info("'%s' (stderr) '%s'", argv[0], line);
                        }
                  }
                  if (outpipe[READ_END] > 0)
                        close(outpipe[READ_END]);
                  if (errpipe[READ_END] > 0)
                        close(errpipe[READ_END]);

                  /* return the childs stdout string */
                  if (result) {
                        result[respos] = '\0';
                        dbg("result='%s'", result);
                        if (reslen)
                              *reslen = respos;
                  }
            }
            waitpid(pid, &status, 0);
            if (WIFEXITED(status)) {
                  info("'%s' returned with status %i", argv[0], WEXITSTATUS(status));
                  if (WEXITSTATUS(status) != 0)
                        retval = -1;
            } else {
                  Perror(space, "'%s' abnormal exit", argv[0]);
                  retval = -1;
            }
      }

      return retval;
}

static
int run_program(struct space *space, const char *command0, char *result,
            size_t ressize, size_t *reslen, int log)
{
      if (command0[0] == '_' && command0[1] == '_')
            return run_program1(space, command0, result, ressize, reslen, log);
      return run_program0(space, command0, result, ressize, reslen, log);
}

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