libbb/gz_open.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Copyright (C) many different people.  If you wrote this, please
   6  * acknowledge your work.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21  * USA
  22  */
  23
  24 #include <sys/types.h>
  25 #include <sys/wait.h>
  26 #include <signal.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30 #include "libbb.h"
  31
  32 FILE *
  33 gz_open(FILE *compressed_file, int *pid)
  34 {
  35         int unzip_pipe[2];
  36
  37         if (pipe(unzip_pipe)!=0) {
  38                 perror_msg("pipe");
  39                 return(NULL);
  40         }
  41
  42     /* If we don't flush, we end up with two copies of anything pending,
  43        one from the parent, one from the child */
  44     fflush(stdout);
  45     fflush(stderr);
  46
  47         if ((*pid = fork()) == -1) {
  48                 perror_msg("fork");
  49                 return(NULL);
  50         }
  51         if (*pid==0) {
  52                 /* child process */
  53                 close(unzip_pipe[0]);
  54                 unzip(compressed_file, fdopen(unzip_pipe[1], "w"));
  55                 fflush(NULL);
  56                 fclose(compressed_file);
  57                 close(unzip_pipe[1]);
  58                 _exit(EXIT_SUCCESS);
  59         }
  60         close(unzip_pipe[1]);
  61         return(fdopen(unzip_pipe[0], "r"));
  62 }
  63
  64 int
  65 gz_close(int gunzip_pid)
  66 {
  67         int status;
  68         int ret;
  69
  70         if (waitpid(gunzip_pid, &status, 0) == -1) {
  71                 perror_msg("waitpid");
  72                 return -1;
  73         }
  74
  75         if (WIFSIGNALED(status)) {
  76                 error_msg("Unzip process killed by signal %d.\n",
  77                         WTERMSIG(status));
  78                 return -1;
  79         }
  80
  81         if (!WIFEXITED(status)) {
  82                 /* shouldn't happen */
  83                 error_msg("Your system is broken: got status %d from waitpid.\n",
  84                                 status);
  85                 return -1;
  86         }
  87
  88         if ((ret = WEXITSTATUS(status))) {
  89                 error_msg("Unzip process failed with return code %d.\n",
  90                                 ret);
  91                 return -1;
  92         }
  93
  94         return 0;
  95 }