From b9199bbdefd32382953dd8c01ec881e5463c5a88 Mon Sep 17 00:00:00 2001 From: Sergey Poznyakoff Date: Fri, 17 Aug 2007 11:40:57 +0000 Subject: (hash_string_insert_prefix): New function (hash_string_insert): Rewrite using hash_string_insert_prefix (safer_name_suffix): Use hash_string_insert_prefix to avoid stack allocation. Bug reported by Dmitry V. Levin --- paxlib/names.c | 47 +++++++++++++++++++++++++++++++++++------------ 1 file changed, 35 insertions(+), 12 deletions(-) diff --git a/paxlib/names.c b/paxlib/names.c index 97d0a95..7e84cec 100644 --- a/paxlib/names.c +++ b/paxlib/names.c @@ -36,15 +36,27 @@ hash_string_compare (void const *name1, void const *name2) 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, char const *string) 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, char const *string) } } +/* 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, bool link_target, bool absolute_names) 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[] = { -- cgit v1.2.1