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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /posix/execvp.c
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Diffstat (limited to 'posix/execvp.c')
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diff --git a/posix/execvp.c b/posix/execvp.c
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+/* Copyright (C) 1991, 1992 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 <unistd.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <limits.h>
+#include <sys/types.h>
+
+#ifndef	HAVE_GNU_LD
+#define	__environ	environ
+#endif
+
+/* Execute FILE, searching in the `PATH' environment variable if it contains
+   no slashes, with arguments ARGV and environment from `environ'.  */
+int
+DEFUN(execvp, (file, argv), CONST char *file AND char *CONST argv[])
+{
+  if (strchr (file, '/') == NULL)
+    {
+      char *path, *p;
+      struct stat st;
+      size_t len;
+      uid_t uid;
+      gid_t gid;
+      int ngroups;
+      gid_t groups[NGROUPS_MAX];
+      char *name;
+
+      path = getenv ("PATH");
+      if (path == NULL)
+	{
+	  /* There is no `PATH' in the environment.
+	     The default search path is the current directory
+	     followed by the path `confstr' returns for `_CS_PATH'.  */
+	  len = confstr (_CS_PATH, (char *) NULL, 0);
+	  path = (char *) __alloca (1 + len);
+	  path[0] = ':';
+	  (void) confstr (_CS_PATH, path + 1, len);
+	}
+
+      len = strlen (file) + 1;
+      name = __alloca (strlen (path) + len);
+      uid = geteuid ();
+      gid = getegid ();
+      ngroups = getgroups (sizeof (groups) / sizeof (groups[0]), groups);
+      p = path;
+      do
+	{
+	  path = p;
+	  p = strchr (path, ':');
+	  if (p == NULL)
+	    p = strchr (path, '\0');
+
+	  if (p == path)
+	    /* Two adjacent colons, or a colon at the beginning or the end
+	       of `PATH' means to search the current directory.  */
+	    (void) memcpy (name, file, len);
+	  else
+	    {
+	      /* Construct the pathname to try.  */
+	      (void) memcpy (name, path, p - path);
+	      name[p - path] = '/';
+	      (void) memcpy (&name[(p - path) + 1], file, len);
+	    }
+	  if (stat (name, &st) == 0 && S_ISREG (st.st_mode))
+	    {
+	      int bit = S_IXOTH;
+	      if (st.st_uid == uid)
+		bit = S_IXUSR;
+	      else if (st.st_gid == gid)
+		bit = S_IXGRP;
+	      else
+		{
+		  register int i;
+		  for (i = 0; i < ngroups; ++i)
+		    if (st.st_gid == groups[i])
+		      {
+			bit = S_IXGRP;
+			break;
+		      }
+		}
+	      if (st.st_mode & bit)
+		{
+		  file = name;
+		  break;
+		}
+	    }
+	}
+      while (*p++ != '\0');
+    }
+
+  return __execve (file, argv, __environ);
+}