libio/iopopen.c

   1 /*
   2 Copyright (C) 1993 Free Software Foundation
   3
   4 This file is part of the GNU IO Library.  This library is free
   5 software; you can redistribute it and/or modify it under the
   6 terms of the GNU General Public License as published by the
   7 Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 This library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU 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 the Free
  17 Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  18
  19 As a special exception, if you link this library with files
  20 compiled with a GNU compiler to produce an executable, this does not cause
  21 the resulting executable to be covered by the GNU General Public License.
  22 This exception does not however invalidate any other reasons why
  23 the executable file might be covered by the GNU General Public License. */
  24
  25 /*  written by Per Bothner (bothner@cygnus.com) */
  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 DEFUN(_IO_proc_open, (fp, command, mode),
  84       _IO_FILE* fp AND const char *command AND const char *mode)
  85 {
  86 #if _IO_HAVE_SYS_WAIT
  87   volatile int read_or_write;
  88   volatile int parent_end, child_end;
  89   int pipe_fds[2];
  90   _IO_pid_t child_pid;
  91   if (_IO_file_is_open(fp))
  92     return NULL;
  93   if (_IO_pipe(pipe_fds) < 0)
  94     return NULL;
  95   if (mode[0] == 'r')
  96     {
  97       parent_end = pipe_fds[0];
  98       child_end = pipe_fds[1];
  99       read_or_write = _IO_NO_WRITES;
 100     }
 101   else
 102     {
 103       parent_end = pipe_fds[1];
 104       child_end = pipe_fds[0];
 105       read_or_write = _IO_NO_READS;
 106     }
 107   ((_IO_proc_file*)fp)->pid = child_pid = _IO_fork();
 108   if (child_pid == 0)
 109     {
 110       int child_std_end = mode[0] == 'r' ? 1 : 0;
 111       _IO_close(parent_end);
 112       if (child_end != child_std_end)
 113         {
 114           _IO_dup2(child_end, child_std_end);
 115           _IO_close(child_end);
 116         }
 117       /* Posix.2:  "popen() shall ensure that any streams from previous
 118          popen() calls that remain open in the parent process are closed
 119          in the new child process." */
 120       while (proc_file_chain)
 121         {
 122           _IO_close (_IO_fileno ((_IO_FILE *) proc_file_chain));
 123           proc_file_chain = proc_file_chain->next;
 124         }
 125
 126       _IO_execl("/bin/sh", "sh", "-c", command, (char *) 0);
 127       _IO__exit(127);
 128     }
 129   _IO_close(child_end);
 130   if (child_pid < 0)
 131     {
 132       _IO_close(parent_end);
 133       return NULL;
 134     }
 135   _IO_fileno(fp) = parent_end;
 136
 137   /* Link into proc_file_chain. */
 138   ((_IO_proc_file*)fp)->next = proc_file_chain;
 139   proc_file_chain = (_IO_proc_file*)fp;
 140
 141   _IO_mask_flags (fp, read_or_write, _IO_NO_READS|_IO_NO_WRITES);
 142   return fp;
 143 #else /* !_IO_HAVE_SYS_WAIT */
 144   return NULL;
 145 #endif
 146 }
 147
 148 _IO_FILE *
 149 DEFUN(_IO_popen, (command, mode),
 150       const char *command AND const char *mode)
 151 {
 152   struct locked_FILE
 153   {
 154     struct _IO_proc_file fpx;
 155 #ifdef _IO_MTSAFE_IO
 156     _IO_lock_t lock;
 157 #endif
 158   } *new_f;
 159   _IO_FILE *fp;
 160
 161   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 162   if (new_f == NULL)
 163     return NULL;
 164 #ifdef _IO_MTSAFE_IO
 165   new_f->fpx.file.file._lock = &new_f->lock;
 166 #endif
 167   fp = (_IO_FILE*)&new_f->fpx;
 168   _IO_init(fp, 0);
 169   _IO_JUMPS(fp) = &_IO_proc_jumps;
 170   _IO_file_init(fp);
 171 #if  !_IO_UNIFIED_JUMPTABLES
 172   ((struct _IO_FILE_plus*)fp)->vtable = NULL;
 173 #endif
 174   if (_IO_proc_open (fp, command, mode) != NULL)
 175     return fp;
 176   free (new_f);
 177   return NULL;
 178 }
 179
 180 strong_alias (_IO_popen, popen);
 181
 182 int
 183 DEFUN(_IO_proc_close, (fp),
 184       _IO_FILE *fp)
 185 {
 186   /* This is not name-space clean. FIXME! */
 187 #if _IO_HAVE_SYS_WAIT
 188   int wstatus;
 189   _IO_proc_file **ptr = &proc_file_chain;
 190   _IO_pid_t wait_pid;
 191   int status = -1;
 192
 193   /* Unlink from proc_file_chain. */
 194   for ( ; *ptr != NULL; ptr = &(*ptr)->next)
 195     {
 196       if (*ptr == (_IO_proc_file*)fp)
 197         {
 198           *ptr = (*ptr)->next;
 199           status = 0;
 200           break;
 201         }
 202     }
 203
 204   if (status < 0 || _IO_close(_IO_fileno(fp)) < 0)
 205     return -1;
 206   /* POSIX.2 Rationale:  "Some historical implementations either block
 207      or ignore the signals SIGINT, SIGQUIT, and SIGHUP while waiting
 208      for the child process to terminate.  Since this behavior is not
 209      described in POSIX.2, such implementations are not conforming." */
 210   do
 211     {
 212       wait_pid = _IO_waitpid (((_IO_proc_file*)fp)->pid, &wstatus, 0);
 213     } while (wait_pid == -1 && errno == EINTR);
 214   if (wait_pid == -1)
 215     return -1;
 216   return wstatus;
 217 #else /* !_IO_HAVE_SYS_WAIT */
 218   return -1;
 219 #endif
 220 }
 221
 222 struct _IO_jump_t _IO_proc_jumps = {
 223   JUMP_INIT_DUMMY,
 224   JUMP_INIT(finish, _IO_file_finish),
 225   JUMP_INIT(overflow, _IO_file_overflow),
 226   JUMP_INIT(underflow, _IO_file_underflow),
 227   JUMP_INIT(uflow, _IO_default_uflow),
 228   JUMP_INIT(pbackfail, _IO_default_pbackfail),
 229   JUMP_INIT(xsputn, _IO_file_xsputn),
 230   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 231   JUMP_INIT(seekoff, _IO_file_seekoff),
 232   JUMP_INIT(seekpos, _IO_default_seekpos),
 233   JUMP_INIT(setbuf, _IO_file_setbuf),
 234   JUMP_INIT(sync, _IO_file_sync),
 235   JUMP_INIT(doallocate, _IO_file_doallocate),
 236   JUMP_INIT(read, _IO_file_read),
 237   JUMP_INIT(write, _IO_file_write),
 238   JUMP_INIT(seek, _IO_file_seek),
 239   JUMP_INIT(close, _IO_proc_close),
 240   JUMP_INIT(stat, _IO_file_stat)
 241 };