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/* Provide an execlp replacement for Minix.
Copyright (C) 1988, 1994, 1995, 1997 Free Software Foundation, Inc.
This file is part of GNU Tar.
GNU Tar 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.
GNU Tar 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 GNU Tar; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
/* For defining NULL. */
#include <stdio.h>
#if STDC_HEADERS
# include <stdlib.h>
#else
char *getenv ();
char *malloc ();
#endif
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#include <sys/types.h>
#include <sys/stat.h>
#if STDC_HEADERS || HAVE_STRING_H
# include <string.h>
#else
# include <strings.h>
# ifndef strchr
# define strchr index
# endif
#endif
/* Synopsis: execlp (file, arg0, arg1... argN, (char *) NULL)
Exec a program, automatically searching for the program through all the
directories on the PATH.
This version is naive about variable argument lists and assumes a quite
straightforward C calling sequence. It will not work on systems having
odd stacks. */
int
execlp (filename, arg0)
char *filename;
char *arg0;
{
register char *p, *path;
register char *fnbuffer;
char **argstart = &arg0;
struct stat statbuf;
extern char **environ;
if (p = getenv ("PATH"), p == NULL)
{
/* Could not find path variable -- try to exec given filename. */
return execve (filename, argstart, environ);
}
/* Make a place to build the filename. We malloc larger than we need,
but we know it will fit in this. */
fnbuffer = malloc (strlen (p) + 1 + strlen (filename));
if (fnbuffer == NULL)
{
errno = ENOMEM;
return -1;
}
/* Try each component of the path to see if the file's there and
executable. */
for (path = p; path; path = p)
{
/* Construct full path name to try. */
if (p = strchr (path, ':'), !p)
strcpy (fnbuffer, path);
else
{
strncpy (fnbuffer, path, p - path);
fnbuffer[p - path] = '\0';
p++; /* skip : for next time */
}
if (strlen (fnbuffer) != 0)
strcat (fnbuffer, "/");
strcat (fnbuffer, filename);
/* Check to see if file is there and is a normal file. */
if (stat (fnbuffer, &statbuf) < 0)
{
if (errno == ENOENT)
continue; /* file not there,keep on looking */
else
goto fail; /* failed for some reason, return */
}
if (!S_ISREG (statbuf.st_mode))
continue;
if (execve (fnbuffer, argstart, environ) < 0
&& errno != ENOENT
&& errno != ENOEXEC)
{
/* Failed, for some other reason besides "file. */
goto fail;
}
/* If we got error ENOEXEC, the file is executable but is not an
object file. Try to execute it as a shell script, returning
error if we can't execute /bin/sh.
FIXME, this code is broken in several ways. Shell scripts
should not in general be executed by the user's SHELL variable
program. On more mature systems, the script can specify with
#!/bin/whatever. Also, this code clobbers argstart[-1] if the
exec of the shell fails. */
if (errno == ENOEXEC)
{
char *shell;
/* Try to execute command "sh arg0 arg1 ...". */
if (shell = getenv ("SHELL"), shell == NULL)
shell = "/bin/sh";
argstart[-1] = shell;
argstart[0] = fnbuffer;
execve (shell, &argstart[-1], environ);
goto fail; /* exec didn't work */
}
/* If we succeeded, the execve() doesn't return, so we can only be
here is if the file hasn't been found yet. Try the next place
on the path. */
}
/* All attempts failed to locate the file. Give up. */
errno = ENOENT;
fail:
free (fnbuffer);
return -1;
}
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