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 #ifndef _IO_close
  72 #define _IO_close close
  73 #endif
  74
  75 struct _IO_proc_file
  76 {
  77   struct _IO_FILE_complete file;
  78   /* Following fields must match those in class procbuf (procbuf.h) */
  79   _IO_pid_t pid;
  80   struct _IO_proc_file *next;
  81 };
  82 typedef struct _IO_proc_file _IO_proc_file;
  83
  84 static struct _IO_proc_file *proc_file_chain = NULL;
  85
  86 _IO_FILE *
  87 _IO_proc_open (fp, command, mode)
  88      _IO_FILE *fp;
  89      const char *command;
  90      const char *mode;
  91 {
  92 #if _IO_HAVE_SYS_WAIT
  93   volatile int read_or_write;
  94   volatile int parent_end, child_end;
  95   int pipe_fds[2];
  96   _IO_pid_t child_pid;
  97   if (_IO_file_is_open (fp))
  98     return NULL;
  99   if (_IO_pipe (pipe_fds) < 0)
 100     return NULL;
 101   if (mode[0] == 'r' && mode[1] == '\0')
 102     {
 103       parent_end = pipe_fds[0];
 104       child_end = pipe_fds[1];
 105       read_or_write = _IO_NO_WRITES;
 106     }
 107   else if (mode[0] == 'w' && mode[1] == '\0')
 108     {
 109       parent_end = pipe_fds[1];
 110       child_end = pipe_fds[0];
 111       read_or_write = _IO_NO_READS;
 112     }
 113   else
 114     {
 115       __set_errno (EINVAL);
 116       return NULL;
 117     }
 118   ((_IO_proc_file *) fp)->pid = child_pid = _IO_fork ();
 119   if (child_pid == 0)
 120     {
 121       int child_std_end = mode[0] == 'r' ? 1 : 0;
 122       _IO_close (parent_end);
 123       if (child_end != child_std_end)
 124         {
 125           _IO_dup2 (child_end, child_std_end);
 126           _IO_close (child_end);
 127         }
 128       /* POSIX.2:  "popen() shall ensure that any streams from previous
 129          popen() calls that remain open in the parent process are closed
 130          in the new child process." */
 131       while (proc_file_chain)
 132         {
 133           _IO_close (_IO_fileno ((_IO_FILE *) proc_file_chain));
 134           proc_file_chain = proc_file_chain->next;
 135         }
 136
 137       _IO_execl ("/bin/sh", "sh", "-c", command, (char *) 0);
 138       _IO__exit (127);
 139     }
 140   _IO_close (child_end);
 141   if (child_pid < 0)
 142     {
 143       _IO_close (parent_end);
 144       return NULL;
 145     }
 146   _IO_fileno (fp) = parent_end;
 147
 148   /* Link into proc_file_chain. */
 149   ((_IO_proc_file *) fp)->next = proc_file_chain;
 150   proc_file_chain = (_IO_proc_file *) fp;
 151
 152   _IO_mask_flags (fp, read_or_write, _IO_NO_READS|_IO_NO_WRITES);
 153   return fp;
 154 #else /* !_IO_HAVE_SYS_WAIT */
 155   return NULL;
 156 #endif
 157 }
 158
 159 _IO_FILE *
 160 _IO_popen (command, mode)
 161      const char *command;
 162      const char *mode;
 163 {
 164   struct locked_FILE
 165   {
 166     struct _IO_proc_file fpx;
 167 #ifdef _IO_MTSAFE_IO
 168     _IO_lock_t lock;
 169 #endif
 170   } *new_f;
 171   _IO_FILE *fp;
 172
 173   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 174   if (new_f == NULL)
 175     return NULL;
 176 #ifdef _IO_MTSAFE_IO
 177   new_f->fpx.file.plus.file._lock = &new_f->lock;
 178 #endif
 179   fp = (_IO_FILE*)&new_f->fpx;
 180   _IO_init (fp, 0);
 181   _IO_JUMPS (fp) = &_IO_proc_jumps;
 182   _IO_file_init (fp);
 183 #if  !_IO_UNIFIED_JUMPTABLES
 184   ((struct _IO_FILE_plus *) fp)->vtable = NULL;
 185 #endif
 186   if (_IO_proc_open (fp, command, mode) != NULL)
 187     return fp;
 188   free (new_f);
 189   return NULL;
 190 }
 191
 192 #ifdef strong_alias
 193 strong_alias (_IO_popen, popen);
 194 #endif
 195
 196 int
 197 _IO_proc_close (fp)
 198      _IO_FILE *fp;
 199 {
 200   /* This is not name-space clean. FIXME! */
 201 #if _IO_HAVE_SYS_WAIT
 202   int wstatus;
 203   _IO_proc_file **ptr = &proc_file_chain;
 204   _IO_pid_t wait_pid;
 205   int status = -1;
 206
 207   /* Unlink from proc_file_chain. */
 208   for ( ; *ptr != NULL; ptr = &(*ptr)->next)
 209     {
 210       if (*ptr == (_IO_proc_file *) fp)
 211         {
 212           *ptr = (*ptr)->next;
 213           status = 0;
 214           break;
 215         }
 216     }
 217
 218   if (status < 0 || _IO_close (_IO_fileno(fp)) < 0)
 219     return -1;
 220   /* POSIX.2 Rationale:  "Some historical implementations either block
 221      or ignore the signals SIGINT, SIGQUIT, and SIGHUP while waiting
 222      for the child process to terminate.  Since this behavior is not
 223      described in POSIX.2, such implementations are not conforming." */
 224   do
 225     {
 226       wait_pid = _IO_waitpid (((_IO_proc_file *) fp)->pid, &wstatus, 0);
 227     }
 228   while (wait_pid == -1 && errno == EINTR);
 229   if (wait_pid == -1)
 230     return -1;
 231   return wstatus;
 232 #else /* !_IO_HAVE_SYS_WAIT */
 233   return -1;
 234 #endif
 235 }
 236
 237 struct _IO_jump_t _IO_proc_jumps = {
 238   JUMP_INIT_DUMMY,
 239   JUMP_INIT(finish, _IO_file_finish),
 240   JUMP_INIT(overflow, _IO_file_overflow),
 241   JUMP_INIT(underflow, _IO_file_underflow),
 242   JUMP_INIT(uflow, _IO_default_uflow),
 243   JUMP_INIT(pbackfail, _IO_default_pbackfail),
 244   JUMP_INIT(xsputn, _IO_file_xsputn),
 245   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 246   JUMP_INIT(seekoff, _IO_file_seekoff),
 247   JUMP_INIT(seekpos, _IO_default_seekpos),
 248   JUMP_INIT(setbuf, _IO_file_setbuf),
 249   JUMP_INIT(sync, _IO_file_sync),
 250   JUMP_INIT(doallocate, _IO_file_doallocate),
 251   JUMP_INIT(read, _IO_file_read),
 252   JUMP_INIT(write, _IO_file_write),
 253   JUMP_INIT(seek, _IO_file_seek),
 254   JUMP_INIT(close, _IO_proc_close),
 255   JUMP_INIT(stat, _IO_file_stat),
 256   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 257   JUMP_INIT(imbue, _IO_default_imbue)
 258 };