libio/iopopen.c

   1 /* Copyright (C) 1993, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU IO Library.
   3    Written by Per Bothner <bothner@cygnus.com>.
   4
   5    This library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU General Public License as
   7    published by the Free Software Foundation; either version 2, or (at
   8    your option) any later version.
   9
  10    This library is distributed in the hope that it will be useful, but
  11    WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this library; see the file COPYING.  If not, write to
  17    the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  18    MA 02111-1307, USA.
  19
  20    As a special exception, if you link this library with files
  21    compiled with a GNU compiler to produce an executable, this does
  22    not cause the resulting executable to be covered by the GNU General
  23    Public License.  This exception does not however invalidate any
  24    other reasons why the executable file might be covered by the GNU
  25    General Public License.  */
  26
  27 #ifndef _POSIX_SOURCE
  28 # define _POSIX_SOURCE
  29 #endif
  30 #include "libioP.h"
  31 #if _IO_HAVE_SYS_WAIT
  32 #include <signal.h>
  33 #include <unistd.h>
  34 #ifdef __STDC__
  35 #include <stdlib.h>
  36 #endif
  37 #ifdef _LIBC
  38 # include <unistd.h>
  39 #endif
  40 #include <sys/types.h>
  41 #include <sys/wait.h>
  42
  43 #ifndef _IO_fork
  44 #define _IO_fork vfork /* defined in libiberty, if needed */
  45 extern _IO_pid_t _IO_fork __P ((void));
  46 #endif
  47
  48 #endif /* _IO_HAVE_SYS_WAIT */
  49
  50 #ifndef _IO_pipe
  51 #define _IO_pipe pipe
  52 extern int _IO_pipe __P ((int des[2]));
  53 #endif
  54
  55 #ifndef _IO_dup2
  56 #define _IO_dup2 dup2
  57 extern int _IO_dup2 __P ((int fd, int fd2));
  58 #endif
  59
  60 #ifndef _IO_waitpid
  61 #define _IO_waitpid waitpid
  62 #endif
  63
  64 #ifndef _IO_execl
  65 #define _IO_execl execl
  66 #endif
  67 #ifndef _IO__exit
  68 #define _IO__exit _exit
  69 #endif
  70
  71 struct _IO_proc_file
  72 {
  73   struct _IO_FILE_plus file;
  74   /* Following fields must match those in class procbuf (procbuf.h) */
  75   _IO_pid_t pid;
  76   struct _IO_proc_file *next;
  77 };
  78 typedef struct _IO_proc_file _IO_proc_file;
  79
  80 static struct _IO_proc_file *proc_file_chain = NULL;
  81
  82 _IO_FILE *
  83 _IO_proc_open (fp, command, mode)
  84      _IO_FILE *fp;
  85      const char *command;
  86      const char *mode;
  87 {
  88 #if _IO_HAVE_SYS_WAIT
  89   volatile int read_or_write;
  90   volatile int parent_end, child_end;
  91   int pipe_fds[2];
  92   _IO_pid_t child_pid;
  93   if (_IO_file_is_open (fp))
  94     return NULL;
  95   if (_IO_pipe (pipe_fds) < 0)
  96     return NULL;
  97   if (mode[0] == 'r')
  98     {
  99       parent_end = pipe_fds[0];
 100       child_end = pipe_fds[1];
 101       read_or_write = _IO_NO_WRITES;
 102     }
 103   else
 104     {
 105       parent_end = pipe_fds[1];
 106       child_end = pipe_fds[0];
 107       read_or_write = _IO_NO_READS;
 108     }
 109   ((_IO_proc_file *) fp)->pid = child_pid = _IO_fork ();
 110   if (child_pid == 0)
 111     {
 112       int child_std_end = mode[0] == 'r' ? 1 : 0;
 113       _IO_close (parent_end);
 114       if (child_end != child_std_end)
 115         {
 116           _IO_dup2 (child_end, child_std_end);
 117           _IO_close (child_end);
 118         }
 119       /* POSIX.2:  "popen() shall ensure that any streams from previous
 120          popen() calls that remain open in the parent process are closed
 121          in the new child process." */
 122       while (proc_file_chain)
 123         {
 124           _IO_close (_IO_fileno ((_IO_FILE *) proc_file_chain));
 125           proc_file_chain = proc_file_chain->next;
 126         }
 127
 128       _IO_execl ("/bin/sh", "sh", "-c", command, (char *) 0);
 129       _IO__exit (127);
 130     }
 131   _IO_close (child_end);
 132   if (child_pid < 0)
 133     {
 134       _IO_close (parent_end);
 135       return NULL;
 136     }
 137   _IO_fileno (fp) = parent_end;
 138
 139   /* Link into proc_file_chain. */
 140   ((_IO_proc_file *) fp)->next = proc_file_chain;
 141   proc_file_chain = (_IO_proc_file *) fp;
 142
 143   _IO_mask_flags (fp, read_or_write, _IO_NO_READS|_IO_NO_WRITES);
 144   return fp;
 145 #else /* !_IO_HAVE_SYS_WAIT */
 146   return NULL;
 147 #endif
 148 }
 149
 150 _IO_FILE *
 151 _IO_popen (command, mode)
 152      const char *command;
 153      const char *mode;
 154 {
 155   struct locked_FILE
 156   {
 157     struct _IO_proc_file fpx;
 158 #ifdef _IO_MTSAFE_IO
 159     _IO_lock_t lock;
 160 #endif
 161   } *new_f;
 162   _IO_FILE *fp;
 163
 164   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 165   if (new_f == NULL)
 166     return NULL;
 167 #ifdef _IO_MTSAFE_IO
 168   new_f->fpx.file.file._lock = &new_f->lock;
 169 #endif
 170   fp = (_IO_FILE*)&new_f->fpx;
 171   _IO_init (fp, 0);
 172   _IO_JUMPS (fp) = &_IO_proc_jumps;
 173   _IO_file_init (fp);
 174 #if  !_IO_UNIFIED_JUMPTABLES
 175   ((struct _IO_FILE_plus *) fp)->vtable = NULL;
 176 #endif
 177   if (_IO_proc_open (fp, command, mode) != NULL)
 178     return fp;
 179   free (new_f);
 180   return NULL;
 181 }
 182
 183 #ifdef strong_alias
 184 strong_alias (_IO_popen, popen);
 185 #endif
 186
 187 int
 188 _IO_proc_close (fp)
 189      _IO_FILE *fp;
 190 {
 191   /* This is not name-space clean. FIXME! */
 192 #if _IO_HAVE_SYS_WAIT
 193   int wstatus;
 194   _IO_proc_file **ptr = &proc_file_chain;
 195   _IO_pid_t wait_pid;
 196   int status = -1;
 197
 198   /* Unlink from proc_file_chain. */
 199   for ( ; *ptr != NULL; ptr = &(*ptr)->next)
 200     {
 201       if (*ptr == (_IO_proc_file *) fp)
 202         {
 203           *ptr = (*ptr)->next;
 204           status = 0;
 205           break;
 206         }
 207     }
 208
 209   if (status < 0 || _IO_close (_IO_fileno(fp)) < 0)
 210     return -1;
 211   /* POSIX.2 Rationale:  "Some historical implementations either block
 212      or ignore the signals SIGINT, SIGQUIT, and SIGHUP while waiting
 213      for the child process to terminate.  Since this behavior is not
 214      described in POSIX.2, such implementations are not conforming." */
 215   do
 216     {
 217       wait_pid = _IO_waitpid (((_IO_proc_file *) fp)->pid, &wstatus, 0);
 218     }
 219   while (wait_pid == -1 && errno == EINTR);
 220   if (wait_pid == -1)
 221     return -1;
 222   return wstatus;
 223 #else /* !_IO_HAVE_SYS_WAIT */
 224   return -1;
 225 #endif
 226 }
 227
 228 struct _IO_jump_t _IO_proc_jumps = {
 229   JUMP_INIT_DUMMY,
 230   JUMP_INIT(finish, _IO_file_finish),
 231   JUMP_INIT(overflow, _IO_file_overflow),
 232   JUMP_INIT(underflow, _IO_file_underflow),
 233   JUMP_INIT(uflow, _IO_default_uflow),
 234   JUMP_INIT(pbackfail, _IO_default_pbackfail),
 235   JUMP_INIT(xsputn, _IO_file_xsputn),
 236   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 237   JUMP_INIT(seekoff, _IO_file_seekoff),
 238   JUMP_INIT(seekpos, _IO_default_seekpos),
 239   JUMP_INIT(setbuf, _IO_file_setbuf),
 240   JUMP_INIT(sync, _IO_file_sync),
 241   JUMP_INIT(doallocate, _IO_file_doallocate),
 242   JUMP_INIT(read, _IO_file_read),
 243   JUMP_INIT(write, _IO_file_write),
 244   JUMP_INIT(seek, _IO_file_seek),
 245   JUMP_INIT(close, _IO_proc_close),
 246   JUMP_INIT(stat, _IO_file_stat)
 247 };