Function validate_exec

src/common/exec.c:70–114

* validate_exec -- validate "path" as an executable file * * returns 0 if the file is found and no error is encountered. * -1 if the regular file "path" does not exist or cannot be executed. * -2 if the file is otherwise valid but cannot be read. */

 *		  -2 if the file is otherwise valid but cannot be read.
 */
int
validate_exec(const char *path)
{
	struct stat buf;
	int			is_r;
	int			is_x;

#ifdef WIN32
	char		path_exe[MAXPGPATH + sizeof(".exe") - 1];

	/* Win32 requires a .exe suffix for stat() */
	if (strlen(path) >= strlen(".exe") &&
		pg_strcasecmp(path + strlen(path) - strlen(".exe"), ".exe") != 0)
	{
		strlcpy(path_exe, path, sizeof(path_exe) - 4);
		strcat(path_exe, ".exe");
		path = path_exe;
	}
#endif

	/*
	 * Ensure that the file exists and is a regular file.
	 *
	 * XXX if you have a broken system where stat() looks at the symlink
	 * instead of the underlying file, you lose.
	 */
	if (stat(path, &buf) < 0)
		return -1;

	if (!S_ISREG(buf.st_mode))
		return -1;

	/*
	 * Ensure that the file is both executable and readable (required for
	 * dynamic loading).
	 */
#ifndef WIN32
	is_r = (access(path, R_OK) == 0);
	is_x = (access(path, X_OK) == 0);
#else
	is_r = buf.st_mode & S_IRUSR;
	is_x = buf.st_mode & S_IXUSR;
#endif
	return is_x ? (is_r ? 0 : -2) : -1;
}


/*