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Eliminate the unwelcome (albeit unlikely) possibility of xmalloc

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failure on deficient systems, and simplify gnulib lgpl dependencies.

(rpl_lstat): Rewrite to use stat() in place of the
xmalloc/lstat combination.  Based on a patch from Bruno Haible.
This commit is contained in:
Jim Meyering 2006-02-02 21:25:06 +00:00
parent 32c694b908
commit b88d20f978
1 changed files with 24 additions and 21 deletions
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45
lib/lstat.c
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@ -1,6 +1,6 @@
/* Work around a bug of lstat on some systems
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free
Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
@ -30,28 +30,28 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "stat-macros.h"
#include "xalloc.h"
/* lstat works differently on Linux and Solaris systems. POSIX (see
`pathname resolution' in the glossary) requires that programs like `ls'
take into consideration the fact that FILE has a trailing slash when
FILE is a symbolic link. On Linux systems, the lstat function already
has the desired semantics (in treating `lstat("symlink/",sbuf)' just like
`lstat("symlink/.",sbuf)', but on Solaris it does not.
`pathname resolution' in the glossary) requires that programs like
`ls' take into consideration the fact that FILE has a trailing slash
when FILE is a symbolic link. On Linux and Solaris 10 systems, the
lstat function already has the desired semantics (in treating
`lstat ("symlink/", sbuf)' just like `lstat ("symlink/.", sbuf)',
but on Solaris 9 and earlier it does not.
If FILE has a trailing slash and specifies a symbolic link,
then append a `.' to FILE and call lstat a second time. */
then use stat() to get more info on the referent of FILE.
If the referent is a non-directory, then set errno to ENOTDIR
and return -1. Otherwise, return stat's result. */
int
rpl_lstat (const char *file, struct stat *sbuf)
{
size_t len;
char *new_file;
int lstat_result = lstat (file, sbuf);
if (lstat_result != 0 || !S_ISLNK (sbuf->st_mode))
@ -59,19 +59,22 @@ rpl_lstat (const char *file, struct stat *sbuf)
len = strlen (file);
if (len == 0 || file[len - 1] != '/')
return lstat_result;
return 0;
/* FILE refers to a symbolic link and the name ends with a slash.
Append a `.' to FILE and repeat the lstat call. */
Call stat() to get info about the link's referent. */
/* Add one for the `.' we'll append, and one more for the trailing NUL. */
new_file = xmalloc (len + 1 + 1);
memcpy (new_file, file, len);
new_file[len] = '.';
new_file[len + 1] = 0;
/* If stat fails, then we do the same. */
if (stat (file, sbuf) != 0)
return -1;
lstat_result = lstat (new_file, sbuf);
free (new_file);
/* If FILE references a directory, return 0. */
if (S_ISDIR (sbuf->st_mode))
return 0;
return lstat_result;
/* Here, we know stat succeeded and FILE references a non-directory.
But it was specified via a name including a trailing slash.
Fail with errno set to ENOTDIR to indicate the contradiction. */
errno = ENOTDIR;
return -1;
}