text: /* Copyright (C) 1993-2017 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
     Written by Per Bothner <bothner@cygnus.com>.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C Library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, see
     <http://www.gnu.org/licenses/>.
  
     As a special exception, if you link the code in this file with
     files compiled with a GNU compiler to produce an executable,
     that does not cause the resulting executable to be covered by
     the GNU Lesser General Public License.  This exception does not
     however invalidate any other reasons why the executable file
     might be covered by the GNU Lesser General Public License.
     This exception applies to code released by its copyright holders
     in files containing the exception.  */
  
  #ifndef _POSIX_SOURCE
  # define _POSIX_SOURCE
  #endif
  #include "libioP.h"
  #include <fcntl.h>
  #include <signal.h>
  #include <unistd.h>
  #include <stdlib.h>
  #ifdef _LIBC
  # include <shlib-compat.h>
  # include <not-cancel.h>
  #endif
  #include <sys/types.h>
  #include <sys/wait.h>
  #include <kernel-features.h>
  
  #ifndef _IO_fork
  #ifdef _LIBC
  #define _IO_fork __fork
  #else
  #define _IO_fork fork /* defined in libiberty, if needed */
  #endif
  extern _IO_pid_t _IO_fork (void) __THROW;
  #endif
  
  #ifndef _IO_dup2
  #ifdef _LIBC
  #define _IO_dup2 __dup2
  #else
  #define _IO_dup2 dup2
  #endif
  extern int _IO_dup2 (int fd, int fd2) __THROW;
  #endif
  
  #ifndef _IO_waitpid
  #ifdef _LIBC
  #define _IO_waitpid waitpid_not_cancel
  #else
  #define _IO_waitpid waitpid
  #endif
  #endif
  
  #ifndef _IO_execl
  #define _IO_execl execl
  #endif
  #ifndef _IO__exit
  #define _IO__exit _exit
  #endif
  
  #ifndef _IO_close
  #ifdef _LIBC
  #define _IO_close close_not_cancel
  #else
  #define _IO_close close
  #endif
  #endif
  
  struct _IO_proc_file
  {
    struct _IO_FILE_plus file;
    /* Following fields must match those in class procbuf (procbuf.h) */
    _IO_pid_t pid;
    struct _IO_proc_file *next;
  };
  typedef struct _IO_proc_file _IO_proc_file;
  
  static const struct _IO_jump_t _IO_proc_jumps;
  
  static struct _IO_proc_file *proc_file_chain;
  
  #ifdef _IO_MTSAFE_IO
  static _IO_lock_t proc_file_chain_lock = _IO_lock_initializer;
  
  static void
  unlock (void *not_used)
  {
    _IO_lock_unlock (proc_file_chain_lock);
  }
  #endif
  
  _IO_FILE *
  _IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode)
  {
    int read_or_write;
    int parent_end, child_end;
    int pipe_fds[2];
    _IO_pid_t child_pid;
  
    int do_read = 0;
    int do_write = 0;
    int do_cloexec = 0;
    while (*mode != '\0')
      switch (*mode++)
        {
        case 'r':
  	do_read = 1;
  	break;
        case 'w':
  	do_write = 1;
  	break;
        case 'e':
  	do_cloexec = 1;
  	break;
        default:
        errout:
  	__set_errno (EINVAL);
  	return NULL;
        }
  
    if ((do_read ^ do_write) == 0)
      goto errout;
  
    if (_IO_file_is_open (fp))
      return NULL;
  
    /* Atomically set the O_CLOEXEC flag for the pipe end used by the
       child process (to avoid leaking the file descriptor in case of a
       concurrent fork).  This is later reverted in the child process.
       When popen returns, the parent pipe end can be O_CLOEXEC or not,
       depending on the 'e' open mode, but there is only one flag which
       controls both descriptors.  The parent end is adjusted below,
       after creating the child process.  (In the child process, the
       parent end should be closed on execve, so O_CLOEXEC remains set
       there.)  */
    if (__pipe2 (pipe_fds, O_CLOEXEC) < 0)
      return NULL;
  
    if (do_read)
      {
        parent_end = pipe_fds[0];
        child_end = pipe_fds[1];
        read_or_write = _IO_NO_WRITES;
      }
    else
      {
        parent_end = pipe_fds[1];
        child_end = pipe_fds[0];
        read_or_write = _IO_NO_READS;
      }
  
    ((_IO_proc_file *) fp)->pid = child_pid = _IO_fork ();
    if (child_pid == 0)
      {
        int child_std_end = do_read ? 1 : 0;
        struct _IO_proc_file *p;
  
        if (child_end != child_std_end)
  	_IO_dup2 (child_end, child_std_end);
        else
  	/* The descriptor is already the one we will use.  But it must
  	   not be marked close-on-exec.  Undo the effects.  */
  	__fcntl (child_end, F_SETFD, 0);
        /* POSIX.2:  "popen() shall ensure that any streams from previous
           popen() calls that remain open in the parent process are closed
  	 in the new child process." */
        for (p = proc_file_chain; p; p = p->next)
  	{
  	  int fd = _IO_fileno ((_IO_FILE *) p);
  
  	  /* If any stream from previous popen() calls has fileno
  	     child_std_end, it has been already closed by the dup2 syscall
  	     above.  */
  	  if (fd != child_std_end)
  	    _IO_close (fd);
  	}
  
        _IO_execl ("/bin/sh", "sh", "-c", command, (char *) 0);
        _IO__exit (127);
      }
    _IO_close (child_end);
    if (child_pid < 0)
      {
        _IO_close (parent_end);
        return NULL;
      }
  
    if (!do_cloexec)
      /* Undo the effects of the pipe2 call which set the
         close-on-exec flag.  */
      __fcntl (parent_end, F_SETFD, 0);
  
    _IO_fileno (fp) = parent_end;
  
    /* Link into proc_file_chain. */
  #ifdef _IO_MTSAFE_IO
    _IO_cleanup_region_start_noarg (unlock);
    _IO_lock_lock (proc_file_chain_lock);
  #endif
    ((_IO_proc_file *) fp)->next = proc_file_chain;
    proc_file_chain = (_IO_proc_file *) fp;
  #ifdef _IO_MTSAFE_IO
    _IO_lock_unlock (proc_file_chain_lock);
    _IO_cleanup_region_end (0);
  #endif
  
    _IO_mask_flags (fp, read_or_write, _IO_NO_READS|_IO_NO_WRITES);
    return fp;
  }
  
  _IO_FILE *
  _IO_new_popen (const char *command, const char *mode)
  {
    struct locked_FILE
    {
      struct _IO_proc_file fpx;
  #ifdef _IO_MTSAFE_IO
      _IO_lock_t lock;
  #endif
    } *new_f;
    _IO_FILE *fp;
  
    new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
    if (new_f == NULL)
      return NULL;
  #ifdef _IO_MTSAFE_IO
    new_f->fpx.file.file._lock = &new_f->lock;
  #endif
    fp = &new_f->fpx.file.file;
    _IO_init_internal (fp, 0);
    _IO_JUMPS (&new_f->fpx.file) = &_IO_proc_jumps;
    _IO_new_file_init_internal (&new_f->fpx.file);
  #if  !_IO_UNIFIED_JUMPTABLES
    new_f->fpx.file.vtable = NULL;
  #endif
    if (_IO_new_proc_open (fp, command, mode) != NULL)
      return (_IO_FILE *) &new_f->fpx.file;
    _IO_un_link (&new_f->fpx.file);
    free (new_f);
    return NULL;
  }
  
  int
  _IO_new_proc_close (_IO_FILE *fp)
  {
    /* This is not name-space clean. FIXME! */
    int wstatus;
    _IO_proc_file **ptr = &proc_file_chain;
    _IO_pid_t wait_pid;
    int status = -1;
  
    /* Unlink from proc_file_chain. */
  #ifdef _IO_MTSAFE_IO
    _IO_cleanup_region_start_noarg (unlock);
    _IO_lock_lock (proc_file_chain_lock);
  #endif
    for ( ; *ptr != NULL; ptr = &(*ptr)->next)
      {
        if (*ptr == (_IO_proc_file *) fp)
  	{
  	  *ptr = (*ptr)->next;
  	  status = 0;
  	  break;
  	}
      }
  #ifdef _IO_MTSAFE_IO
    _IO_lock_unlock (proc_file_chain_lock);
    _IO_cleanup_region_end (0);
  #endif
  
    if (status < 0 || _IO_close (_IO_fileno(fp)) < 0)
      return -1;
    /* POSIX.2 Rationale:  "Some historical implementations either block
       or ignore the signals SIGINT, SIGQUIT, and SIGHUP while waiting
       for the child process to terminate.  Since this behavior is not
       described in POSIX.2, such implementations are not conforming." */
    do
      {
        wait_pid = _IO_waitpid (((_IO_proc_file *) fp)->pid, &wstatus, 0);
      }
    while (wait_pid == -1 && errno == EINTR);
    if (wait_pid == -1)
      return -1;
    return wstatus;
  }
  
  static const struct _IO_jump_t _IO_proc_jumps libio_vtable = {
    JUMP_INIT_DUMMY,
    JUMP_INIT(finish, _IO_new_file_finish),
    JUMP_INIT(overflow, _IO_new_file_overflow),
    JUMP_INIT(underflow, _IO_new_file_underflow),
    JUMP_INIT(uflow, _IO_default_uflow),
    JUMP_INIT(pbackfail, _IO_default_pbackfail),
    JUMP_INIT(xsputn, _IO_new_file_xsputn),
    JUMP_INIT(xsgetn, _IO_default_xsgetn),
    JUMP_INIT(seekoff, _IO_new_file_seekoff),
    JUMP_INIT(seekpos, _IO_default_seekpos),
    JUMP_INIT(setbuf, _IO_new_file_setbuf),
    JUMP_INIT(sync, _IO_new_file_sync),
    JUMP_INIT(doallocate, _IO_file_doallocate),
    JUMP_INIT(read, _IO_file_read),
    JUMP_INIT(write, _IO_new_file_write),
    JUMP_INIT(seek, _IO_file_seek),
    JUMP_INIT(close, _IO_new_proc_close),
    JUMP_INIT(stat, _IO_file_stat),
    JUMP_INIT(showmanyc, _IO_default_showmanyc),
    JUMP_INIT(imbue, _IO_default_imbue)
  };
  
  strong_alias (_IO_new_popen, __new_popen)
  versioned_symbol (libc, _IO_new_popen, _IO_popen, GLIBC_2_1);
  versioned_symbol (libc, __new_popen, popen, GLIBC_2_1);
  versioned_symbol (libc, _IO_new_proc_open, _IO_proc_open, GLIBC_2_1);
  versioned_symbol (libc, _IO_new_proc_close, _IO_proc_close, GLIBC_2_1);
  