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/***************************************************************************
* Copyright (C) 2008 by Alexander Block *
* ablock@blocksoftware.net *
* *
* 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 of the License, 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. *
***************************************************************************/
#include "config.h"
#include "locate.h"
#include "error.h"
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <sys/wait.h>
#define DEFAULT_PATH "/bin:/usr/bin"
/*
* The locate code is taken from the original glibc implementation of execvp
* and simplified for our needs.
*/
static int check_access(const char* path)
{
return access(path, X_OK);
}
int hexec_locate(const char* file, char** out)
{
if (*file == '\0')
{
/* We check the simple case first. */
errno = ENOENT;
return -1;
}
//hexec_log("locate: %s\n", file);
if (strchr (file, '/') != NULL)
{
/* Don't search when it contains a slash. */
*out = strdup(file);
return 0;
}
size_t pathlen;
size_t alloclen = 0;
char *path = getenv ("PATH");
if (path == NULL)
{
pathlen = strlen(DEFAULT_PATH);
alloclen = pathlen + 1;
}
else
{
pathlen = strlen (path);
}
size_t len = strlen (file) + 1;
alloclen += pathlen + len + 1;
char *name;
char *path_malloc = NULL;
path_malloc = name = malloc (alloclen);
if (name == NULL)
return -1;
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'. */
path = name + pathlen + len + 1;
path[0] = ':';
memcpy(path, DEFAULT_PATH, pathlen + 1);
}
/* Copy the file name at the top. */
name = (char *) memcpy (name + pathlen + 1, file, len);
/* And add the slash. */
*--name = '/';
bool got_eacces = false;
char *p = path;
do
{
char *startp;
path = p;
p = strchrnul (path, ':');
if (p == path)
{
/* Two adjacent colons, or a colon at the beginning or the end
of `PATH' means to search the current directory. */
startp = name + 1;
}
else
{
startp = (char *) memcpy (name - (p - path), path, p - path);
}
/* Try this name. */
if (check_access(startp))
{
if (errno == EACCES)
got_eacces = true;
}
else
{
*out = strdup(startp);
free(path_malloc);
//hexec_log("result=%s\n", *out);
return 0;
}
}
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;
}
free (path_malloc);
/* Return the error from the last attempt (probably ENOENT). */
return -1;
}
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