remote: make copy_ref() perform a deep copy

To ensure that copied refs can always be freed w/o causing a double-free, make copy_ref() perform a deep copy. Also have copy_ref() return NULL if asked to copy NULL to simplify things for the caller. Background: currently copy_ref() performs a shallow copy. This is fine for current callers who never free the result and/or only copy refs which contain NULL pointers. But copy_ref() is about to gain a new caller (guess_remote_head()) which copies refs where peer_ref is not NULL and the caller of guess_remote_head() will want to free the result. Signed-off-by: Jay Soffian <jaysoffian@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jay Soffian committed Feb 27, 2009 at 14:10 UTC 7b3db095d53d19e08b27114d8706ff3be6693af7

1 file changed +13 -5

remote.c

+13 -5

@@ -779,10 +779,18 @@ struct ref *alloc_ref(const char *name)

779

780 static struct ref *copy_ref(const struct ref *ref)

781 {

782 - struct ref *ret = xmalloc(sizeof(struct ref) + strlen(ref->name) + 1);

783 - memcpy(ret, ref, sizeof(struct ref) + strlen(ref->name) + 1);

784 - ret->next = NULL;

785 - return ret;

782 + struct ref *cpy;

783 + size_t len;

784 + if (!ref)

785 + return NULL;

786 + len = strlen(ref->name);

787 + cpy = xmalloc(sizeof(struct ref) + len + 1);

788 + memcpy(cpy, ref, sizeof(struct ref) + len + 1);

789 + cpy->next = NULL;

790 + cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;

791 + cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;

792 + cpy->peer_ref = copy_ref(ref->peer_ref);

793 + return cpy;

794 }

795

796 struct ref *copy_ref_list(const struct ref *ref)

@@ -801,6 +809,7 @@ static void free_ref(struct ref *ref)

809 {

810 if (!ref)

811 return;

812 + free_ref(ref->peer_ref);

813 free(ref->remote_status);

814 free(ref->symref);

815 free(ref);

@@ -811,7 +820,6 @@ void free_refs(struct ref *ref)

820 struct ref *next;

821 while (ref) {

822 next = ref->next;

814 - free(ref->peer_ref);

823 free_ref(ref);

824 ref = next;

825 }