From 1820745a0af0768d9dcd515b98ad038ff9f15f23 Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Wed, 24 Jul 2019 15:21:56 +0100 Subject: [PATCH] libctf: don't leak hash keys or values on value replacement When a ctf_dynhash_insert() finds a slot already existing, it should call the key and value free functions on the existing key and value and move the passed-in key into place, so that the lifetime rules for hash keys are always the same no matter whether the key existed or not but neither are the keys or values leaked. New in v3. v5: fix tabdamage. libctf/ * ctf-hash.c (ctf_hashtab_insert): Pass in the key and value freeing functions: if set, free the key and value if the slot already exists. Always reassign the key. (ctf_dynhash_insert): Adjust call appropriately. (ctf_hash_insert_type): Likewise. --- libctf/ChangeLog | 8 ++++++++ libctf/ctf-hash.c | 18 ++++++++++++++---- 2 files changed, 22 insertions(+), 4 deletions(-) diff --git a/libctf/ChangeLog b/libctf/ChangeLog index 28be7579668..08a2e3a5361 100644 --- a/libctf/ChangeLog +++ b/libctf/ChangeLog @@ -1,3 +1,11 @@ +2019-07-30 Nick Alcock + + * ctf-hash.c (ctf_hashtab_insert): Pass in the key and value + freeing functions: if set, free the key and value if the slot + already exists. Always reassign the key. + (ctf_dynhash_insert): Adjust call appropriately. + (ctf_hash_insert_type): Likewise. + 2019-08-03 Nick Alcock * ctf-create.c (ctf_add_type): Look up and use the forwarded-to diff --git a/libctf/ctf-hash.c b/libctf/ctf-hash.c index c6233eb6767..59fceed6253 100644 --- a/libctf/ctf-hash.c +++ b/libctf/ctf-hash.c @@ -152,7 +152,9 @@ ctf_hashtab_lookup (struct htab *htab, const void *key, enum insert_option inser } static ctf_helem_t * -ctf_hashtab_insert (struct htab *htab, void *key, void *value) +ctf_hashtab_insert (struct htab *htab, void *key, void *value, + ctf_hash_free_fun key_free, + ctf_hash_free_fun value_free) { ctf_helem_t **slot; @@ -169,8 +171,15 @@ ctf_hashtab_insert (struct htab *htab, void *key, void *value) *slot = malloc (sizeof (ctf_helem_t)); if (!*slot) return NULL; - (*slot)->key = key; } + else + { + if (key_free) + key_free ((*slot)->key); + if (value_free) + value_free ((*slot)->value); + } + (*slot)->key = key; (*slot)->value = value; return *slot; } @@ -180,7 +189,8 @@ ctf_dynhash_insert (ctf_dynhash_t *hp, void *key, void *value) { ctf_helem_t *slot; - slot = ctf_hashtab_insert (hp->htab, key, value); + slot = ctf_hashtab_insert (hp->htab, key, value, + hp->key_free, hp->value_free); if (!slot) return errno; @@ -317,7 +327,7 @@ ctf_hash_insert_type (ctf_hash_t *hp, ctf_file_t *fp, uint32_t type, return 0; /* Just ignore empty strings on behalf of caller. */ if (ctf_hashtab_insert ((struct htab *) hp, (char *) str, - (void *) (ptrdiff_t) type) != NULL) + (void *) (ptrdiff_t) type, NULL, NULL) != NULL) return 0; return errno; } -- 2.30.2