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Re: [Bug-tar] Re: [Bug-cpio] [PATCH] lib/paxnames.c: Do not use alloca t
From: |
Sergey Poznyakoff |
Subject: |
Re: [Bug-tar] Re: [Bug-cpio] [PATCH] lib/paxnames.c: Do not use alloca to avoid stack overflow |
Date: |
Fri, 17 Aug 2007 14:50:10 +0300 |
Dmitry V. Levin <address@hidden> ha escrit:
> I do not suggest to remove xstrdup completely, just replace it with
> xmalloc; nothing more, nothing less.
Yes, indeed, I misread it. Thanks for pointing that out. I have
installed the following patch:
Index: paxlib/names.c
===================================================================
RCS file: /cvsroot/paxutils/paxutils/paxlib/names.c,v
retrieving revision 1.2
diff -p -u -r1.2 names.c
--- paxlib/names.c 27 Jun 2007 13:49:33 -0000 1.2
+++ paxlib/names.c 17 Aug 2007 11:35:04 -0000
@@ -36,15 +36,27 @@ hash_string_compare (void const *name1,
return strcmp (name1, name2) == 0;
}
-/* Return zero if TABLE contains a copy of STRING; otherwise, insert a
- copy of STRING to TABLE and return 1. */
-bool
-hash_string_insert (Hash_table **table, char const *string)
+/* Return zero if TABLE contains a LEN-character long prefix of STRING,
+ otherwise, insert a newly allocated copy of this prefix to TABLE and
+ return 1. If RETURN_PREFIX is not NULL, point it to the allocated
+ copy. */
+static bool
+hash_string_insert_prefix (Hash_table **table, char const *string, size_t len,
+ const char **return_prefix)
{
Hash_table *t = *table;
- char *s = xstrdup (string);
+ char *s;
char *e;
+ if (len)
+ {
+ s = xmalloc (len + 1);
+ memcpy (s, string, len);
+ s[len] = 0;
+ }
+ else
+ s = xstrdup (string);
+
if (! ((t
|| (*table = t = hash_initialize (0, 0, hash_string_hasher,
hash_string_compare, 0)))
@@ -52,7 +64,11 @@ hash_string_insert (Hash_table **table,
xalloc_die ();
if (e == s)
- return 1;
+ {
+ if (return_prefix)
+ *return_prefix = s;
+ return 1;
+ }
else
{
free (s);
@@ -60,6 +76,14 @@ hash_string_insert (Hash_table **table,
}
}
+/* Return zero if TABLE contains a copy of STRING; otherwise, insert a
+ copy of STRING to TABLE and return 1. */
+bool
+hash_string_insert (Hash_table **table, char const *string)
+{
+ return hash_string_insert_prefix (table, string, 0, NULL);
+}
+
/* Return 1 if TABLE contains STRING. */
bool
hash_string_lookup (Hash_table const *table, char const *string)
@@ -88,7 +112,8 @@ removed_prefixes_p (void)
If ABSOLUTE_NAMES is 0, strip filesystem prefix from the file name. */
char *
-safer_name_suffix (char const *file_name, bool link_target, bool
absolute_names)
+safer_name_suffix (char const *file_name, bool link_target,
+ bool absolute_names)
{
char const *p;
@@ -121,11 +146,9 @@ safer_name_suffix (char const *file_name
if (prefix_len)
{
- char *prefix = alloca (prefix_len + 1);
- memcpy (prefix, file_name, prefix_len);
- prefix[prefix_len] = '\0';
-
- if (hash_string_insert (&prefix_table[link_target], prefix))
+ const char **prefix;
+ if (hash_string_insert_prefix (&prefix_table[link_target], file_name,
+ prefix_len, &prefix))
{
static char const *const diagnostic[] =
{
Regards,
Sergey