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   int read_or_write;
  88   int pipe_fds[2];
  89   int parent_end, child_end;
  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, NULL);
 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   _IO_proc_file *fpx = (_IO_proc_file*)malloc(sizeof(_IO_proc_file));
 153   _IO_FILE *fp = (_IO_FILE*)fpx;
 154   if (fp == NULL)
 155     return NULL;
 156   _IO_init(fp, 0);
 157   _IO_JUMPS(fp) = &_IO_proc_jumps;
 158   _IO_file_init(fp);
 159 #if  !_IO_UNIFIED_JUMPTABLES
 160   ((struct _IO_FILE_plus*)fp)->vtable = NULL;
 161 #endif
 162   if (_IO_proc_open (fp, command, mode) != NULL)
 163     return fp;
 164   free (fpx);
 165   return NULL;
 166 }
 167
 168 strong_alias (_IO_popen, popen);
 169
 170 int
 171 DEFUN(_IO_proc_close, (fp),
 172       _IO_FILE *fp)
 173 {
 174   /* This is not name-space clean. FIXME! */
 175 #if _IO_HAVE_SYS_WAIT
 176   int wstatus;
 177   _IO_proc_file **ptr = &proc_file_chain;
 178   _IO_pid_t wait_pid;
 179   int status = -1;
 180
 181   /* Unlink from proc_file_chain. */
 182   for ( ; *ptr != NULL; ptr = &(*ptr)->next)
 183     {
 184       if (*ptr == (_IO_proc_file*)fp)
 185         {
 186           *ptr = (*ptr)->next;
 187           status = 0;
 188           break;
 189         }
 190     }
 191
 192   if (status < 0 || _IO_close(_IO_fileno(fp)) < 0)
 193     return -1;
 194   /* POSIX.2 Rationale:  "Some historical implementations either block
 195      or ignore the signals SIGINT, SIGQUIT, and SIGHUP while waiting
 196      for the child process to terminate.  Since this behavior is not
 197      described in POSIX.2, such implementations are not conforming." */
 198   do
 199     {
 200       wait_pid = _IO_waitpid (((_IO_proc_file*)fp)->pid, &wstatus, 0);
 201     } while (wait_pid == -1 && errno == EINTR);
 202   if (wait_pid == -1)
 203     return -1;
 204   return wstatus;
 205 #else /* !_IO_HAVE_SYS_WAIT */
 206   return -1;
 207 #endif
 208 }
 209
 210 struct _IO_jump_t _IO_proc_jumps = {
 211   JUMP_INIT_DUMMY,
 212   JUMP_INIT(finish, _IO_file_finish),
 213   JUMP_INIT(overflow, _IO_file_overflow),
 214   JUMP_INIT(underflow, _IO_file_underflow),
 215   JUMP_INIT(uflow, _IO_default_uflow),
 216   JUMP_INIT(pbackfail, _IO_default_pbackfail),
 217   JUMP_INIT(xsputn, _IO_file_xsputn),
 218   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 219   JUMP_INIT(seekoff, _IO_file_seekoff),
 220   JUMP_INIT(seekpos, _IO_default_seekpos),
 221   JUMP_INIT(setbuf, _IO_file_setbuf),
 222   JUMP_INIT(sync, _IO_file_sync),
 223   JUMP_INIT(doallocate, _IO_file_doallocate),
 224   JUMP_INIT(read, _IO_file_read),
 225   JUMP_INIT(write, _IO_file_write),
 226   JUMP_INIT(seek, _IO_file_seek),
 227   JUMP_INIT(close, _IO_proc_close),
 228   JUMP_INIT(stat, _IO_file_stat)
 229 };