lib/libarchive/filter_fork.c

   1 /*-
   2  * Copyright (c) 2007 Joerg Sonnenberger
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "archive_platform.h"
  27
  28 /* This capability is only available on POSIX systems. */
  29 #if defined(HAVE_PIPE) && defined(HAVE_VFORK) && defined(HAVE_FCNTL)
  30
  31 __FBSDID("$FreeBSD$");
  32
  33 #if defined(HAVE_POLL)
  34 #  if defined(HAVE_POLL_H)
  35 #    include <poll.h>
  36 #  elif defined(HAVE_SYS_POLL_H)
  37 #    include <sys/poll.h>
  38 #  endif
  39 #elif defined(HAVE_SELECT)
  40 #  if defined(HAVE_SYS_SELECT_H)
  41 #    include <sys/select.h>
  42 #  elif defined(HAVE_UNISTD_H)
  43 #    include <unistd.h>
  44 #  endif
  45 #endif
  46 #ifdef HAVE_FCNTL_H
  47 #  include <fcntl.h>
  48 #endif
  49 #ifdef HAVE_UNISTD_H
  50 #  include <unistd.h>
  51 #endif
  52
  53 #include "filter_fork.h"
  54
  55 pid_t
  56 __archive_create_child(const char *path, int *child_stdin, int *child_stdout)
  57 {
  58         pid_t child;
  59         int stdin_pipe[2], stdout_pipe[2], tmp;
  60
  61         if (pipe(stdin_pipe) == -1)
  62                 goto state_allocated;
  63         if (stdin_pipe[0] == STDOUT_FILENO) {
  64                 if ((tmp = dup(stdin_pipe[0])) == -1)
  65                         goto stdin_opened;
  66                 close(stdin_pipe[0]);
  67                 stdin_pipe[0] = tmp;
  68         }
  69         if (pipe(stdout_pipe) == -1)
  70                 goto stdin_opened;
  71         if (stdout_pipe[1] == STDIN_FILENO) {
  72                 if ((tmp = dup(stdout_pipe[1])) == -1)
  73                         goto stdout_opened;
  74                 close(stdout_pipe[1]);
  75                 stdout_pipe[1] = tmp;
  76         }
  77
  78         switch ((child = vfork())) {
  79         case -1:
  80                 goto stdout_opened;
  81         case 0:
  82                 close(stdin_pipe[1]);
  83                 close(stdout_pipe[0]);
  84                 if (dup2(stdin_pipe[0], STDIN_FILENO) == -1)
  85                         _exit(254);
  86                 if (stdin_pipe[0] != STDIN_FILENO)
  87                         close(stdin_pipe[0]);
  88                 if (dup2(stdout_pipe[1], STDOUT_FILENO) == -1)
  89                         _exit(254);
  90                 if (stdout_pipe[1] != STDOUT_FILENO)
  91                         close(stdout_pipe[1]);
  92                 execlp(path, path, (char *)NULL);
  93                 _exit(254);
  94         default:
  95                 close(stdin_pipe[0]);
  96                 close(stdout_pipe[1]);
  97
  98                 *child_stdin = stdin_pipe[1];
  99                 fcntl(*child_stdin, F_SETFL, O_NONBLOCK);
 100                 *child_stdout = stdout_pipe[0];
 101                 fcntl(*child_stdout, F_SETFL, O_NONBLOCK);
 102         }
 103
 104         return child;
 105
 106 stdout_opened:
 107         close(stdout_pipe[0]);
 108         close(stdout_pipe[1]);
 109 stdin_opened:
 110         close(stdin_pipe[0]);
 111         close(stdin_pipe[1]);
 112 state_allocated:
 113         return -1;
 114 }
 115
 116 void
 117 __archive_check_child(int in, int out)
 118 {
 119 #if defined(HAVE_POLL)
 120         struct pollfd fds[2];
 121
 122         fds[0].fd = in;
 123         fds[0].events = POLLOUT;
 124         fds[1].fd = out;
 125         fds[1].events = POLLIN;
 126
 127         poll(fds, 2, -1); /* -1 == INFTIM, wait forever */
 128 #elif defined(HAVE_SELECT)
 129         fd_set fds_in, fds_out, fds_error;
 130
 131         FD_ZERO(&fds_in);
 132         FD_SET(out, &fds_in);
 133         FD_ZERO(&fds_out);
 134         FD_SET(in, &fds_out);
 135         FD_ZERO(&fds_error);
 136         FD_SET(in, &fds_error);
 137         FD_SET(out, &fds_error);
 138         select(in < out ? out + 1 : in + 1, &fds_in, &fds_out, &fds_error, NULL);
 139 #else
 140         sleep(1);
 141 #endif
 142 }
 143
 144 #endif /* defined(HAVE_PIPE) && defined(HAVE_VFORK) && defined(HAVE_FCNTL) */