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