Really add readpipe to the repo.

2026-03-09 20:33:03 +00:00 · 2002-02-05 10:14:20 +00:00
parent ea6cfe9ebd
commit 11ee57d90c
1 changed files with 96 additions and 0 deletions
--- a/lib/readpipe.c
+++ b/lib/readpipe.c
@@ -0,0 +1,96 @@
+/* Open a pipe to read from a program without intermediary sh.
+   Copyright (C) 1992, 1997 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* Written by David MacKenzie.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdio.h>
+
+#if __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+/* Open a pipe to read from a program without intermediary sh.  Checks
+   PATH.  Sample use:
+
+   stream = readpipe ("progname", "arg1", "arg2", (char *) 0);
+
+   Return 0 on error.  */
+
+#if __STDC__
+FILE *
+readpipe (char *progname, ...)
+#else
+FILE *
+readpipe (va_alist)
+#endif
+{
+#if ! __STDC__
+  char *progname;
+#endif
+  int fds[2];
+  va_list ap;
+  char *args[100];
+  int argno = 0;
+
+  /* Copy arguments into `args'. */
+#if __STDC__
+  va_start (ap, progname);
+#else
+  va_start (ap);
+  progname = va_arg (ap, char *);
+#endif
+  args[argno++] = progname;
+  while ((args[argno++] = va_arg (ap, char *)) != NULL)
+    ;
+  va_end (ap);
+
+  if (pipe (fds) == -1)
+    return 0;
+
+  switch (fork ())
+    {
+    case 0:			/* Child.  Write to pipe. */
+      close (fds[0]);		/* Not needed. */
+      if (fds[1] != 1)		/* Redirect 1 (stdout) only if needed.  */
+	{
+	  close (1);		/* We don't want the old stdout. */
+	  if (dup (fds[1]) == 0)/* Maybe stdin was closed. */
+	    {
+	      dup (fds[1]);	/* Guaranteed to dup to 1 (stdout). */
+	      close (0);
+	    }
+	  close (fds[1]);	/* No longer needed. */
+	}
+      execvp (args[0], args);
+      _exit (2);		/* 2 for `cmp'. */
+    case -1:			/* Error. */
+      return 0;
+    default:			/* Parent.  Read from pipe. */
+      close (fds[1]);		/* Not needed. */
+      return fdopen (fds[0], "r");
+    }
+}