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/* Copyright (C) 1991, 1992, 1995, 1996 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 <unistd.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <paths.h>
/* Execute FILE, searching in the `PATH' environment variable if it contains
no slashes, with arguments ARGV and environment from `environ'. */
int
execvp (file, argv)
const char *file;
char *const argv[];
{
int got_eacces = 0;
void execute (const char *file, char *const argv[])
{
execv (file, argv);
if (errno == ENOEXEC)
{
/* The file is accessible but it is not an executable file.
Invoke the shell to interpret it as a script. */
/* Count the arguments. */
int argc = 0;
while (argv[argc++])
;
/* Construct an argument list for the shell. */
{
char *new_argv[argc + 1];
new_argv[0] = (char *) _PATH_BSHELL;
new_argv[1] = (char *) file;
while (argc > 1)
{
new_argv[argc] = argv[argc - 1];
--argc;
}
/* Execute the shell. */
execv (new_argv[0], new_argv);
}
}
}
if (strchr (file, '/') != NULL)
/* Don't search when it contains a slash. */
execute (file, argv);
else
{
char *path, *p, *name;
size_t len;
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);
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);
}
/* Try to execute this name. If it works, execv will not return. */
execute (name, argv);
switch (errno)
{
case EACCES:
/* Record the we got a `Permission denied' error. If we end
up finding no executable we can use, we want to diagnose
that we did find one but were denied access. */
got_eacces = 1;
case ENOENT:
/* Those errors indicate the file is missing or not executable
by us, in which case we want to just try the next path
directory. */
break;
default:
/* Some other error means we found an executable file, but
something went wrong executing it; return the error to our
caller. */
return -1;
}
}
while (*p++ != '\0');
}
/* We tried every element and none of them worked. */
if (got_eacces)
/* At least one failure was due to permissions, so report that error. */
errno = EACCES;
/* Return the error from the last attempt (probably ENOENT). */
return -1;
}
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