From e93869ad4ae4ba81235a53857e5f2255f104adfb Mon Sep 17 00:00:00 2001
From: roland <roland>
Date: Mon, 1 Jul 1991 22:30:15 +0000
Subject: [PATCH] Initial revision

---
 sysdeps/posix/pipestream.c | 171 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 sysdeps/posix/pipestream.c

diff --git a/sysdeps/posix/pipestream.c b/sysdeps/posix/pipestream.c
new file mode 100644
index 0000000000..e5103cfbdf
--- /dev/null
+++ b/sysdeps/posix/pipestream.c
@@ -0,0 +1,171 @@
+/* Copyright (C) 1991 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <stddef.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#define	SH_PATH	"/bin/sh"	/* Shell to run.  */
+#define	SH_NAME	"sh"		/* Name to give it.  */
+
+/* Structure describing a popen child.  */
+struct child
+  {
+    /* It is important that the first member of this structure be an `int' that
+       is the file descriptor.  This is because the `fileno' function assumes
+       that __cookie(STREAM) points to the file descriptor.  */
+    int fd;
+    pid_t pid;
+  };
+
+#ifndef	FORK
+#define	FORK	fork
+#endif
+
+/* Open a new stream that is a one-way pipe to a
+   child process running the given shell command.  */
+FILE *
+DEFUN(popen, (command, mode), CONST char *command AND CONST char *mode)
+{
+  pid_t pid;
+  int pipedes[2];
+  FILE *stream;
+  struct child *child;
+
+  if (command == NULL || mode == NULL || (*mode != 'r' && *mode != 'w'))
+    {
+      errno = EINVAL;
+      return NULL;
+    }
+
+  /* Create the pipe.  */
+  if (pipe(pipedes) < 0)
+    return NULL;
+
+  /* Fork off the child.  */
+  pid = FORK();
+  if (pid == (pid_t) -1)
+    {
+      /* The fork failed.  */
+      (void) close(pipedes[0]);
+      (void) close(pipedes[1]);
+      return NULL;
+    }
+  else if (pid == (pid_t) 0)
+    {
+      /* We are the child side.  Make the write side of
+	 the pipe be stdin or the read side be stdout.  */
+
+      CONST char *new_argv[4];
+
+      if ((*mode == 'r' ? dup2(pipedes[STDIN_FILENO], STDOUT_FILENO) :
+	  dup2(pipedes[STDOUT_FILENO], STDIN_FILENO)) < 0)
+	_exit(127);
+
+      /* Close the pipe descriptors.  */
+      (void) close(pipedes[STDIN_FILENO]);
+      (void) close(pipedes[STDOUT_FILENO]);
+
+      /* Exec the shell.  */
+      new_argv[0] = SH_NAME;
+      new_argv[1] = "-c";
+      new_argv[2] = command;
+      new_argv[3] = NULL;
+      (void) execve(SH_PATH, (char *CONST *) new_argv, environ);
+      /* Die if it failed.  */
+      _exit(127);
+    }
+
+  /* We are the parent side.  */
+
+  /* Close the irrelevant side of the pipe and open the relevant side as a
+     new stream.  Mark our side of the pipe to close on exec, so new popen
+     children won't see it.  */
+  if (*mode == 'r')
+    {
+      (void) close(pipedes[STDOUT_FILENO]);
+      (void) fcntl (pipedes[STDIN_FILENO], F_SETFD, FD_CLOEXEC);
+      stream = fdopen(pipedes[STDIN_FILENO], mode);
+    }
+  else
+    {
+      (void) close(pipedes[STDIN_FILENO]);
+      (void) fcntl (pipedes[STDOUT_FILENO], F_SETFD, FD_CLOEXEC);
+      stream = fdopen(pipedes[STDOUT_FILENO], mode);
+    }
+
+  if (stream == NULL)
+    goto error;
+
+  child = (struct child *) malloc(sizeof(struct child));
+  if (child == NULL)
+    goto error;
+  child->fd = fileno(stream);
+  child->pid = pid;
+  stream->__cookie = (PTR) child;
+  stream->__ispipe = 1;
+  return stream;
+
+ error:;
+  {
+    /* The stream couldn't be opened or the child structure couldn't be
+       allocated.  Kill the child and close the other side of the pipe.  */
+    int save = errno;
+    (void) kill(pid, SIGKILL);
+    if (stream == NULL)
+      (void) close(pipedes[*mode == 'r' ? STDOUT_FILENO : STDIN_FILENO]);
+    else
+      (void) fclose(stream);
+    (void) waitpid(pid, (int *) NULL, 0);
+    errno = save;
+    return NULL;
+  }
+}
+
+/* Close a stream opened by popen and return its status.
+   Returns -1 if the stream was not opened by popen.  */
+int
+DEFUN(pclose, (stream), register FILE *stream)
+{
+  pid_t pid;
+  int status;
+
+  if (!__validfp(stream) || !stream->__ispipe)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
+  pid = ((struct child *) stream->__cookie)->pid;
+  free(stream->__cookie);
+  stream->__cookie = (PTR) &stream->__fileno;
+  stream->__ispipe = 0;
+  if (fclose(stream))
+    return -1;
+
+  if (waitpid(pid, &status, 0) != pid)
+    status = -1;
+  return status;
+}
-- 
2.11.0