[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] tools/xenstore: let hashtable_add() fail in case of existing entry
commit 901a740b3215284d0a8cd7c30c872012f10c4428 Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Mon Aug 14 09:46:50 2023 +0200 Commit: Julien Grall <jgrall@xxxxxxxxxx> CommitDate: Fri Aug 18 13:44:48 2023 +0100 tools/xenstore: let hashtable_add() fail in case of existing entry Silently adding another entry with the same key to a hashtable is a perfect receipt for later failure with hard to diagnose symptoms. Let hashtable_add() fail in case another entry with the same key is already existing. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx> --- tools/xenstore/hashtable.c | 40 ++++++++++++++++++++++++++++------------ tools/xenstore/hashtable.h | 6 ------ 2 files changed, 28 insertions(+), 18 deletions(-) diff --git a/tools/xenstore/hashtable.c b/tools/xenstore/hashtable.c index 9daddd9782..88e14c4c57 100644 --- a/tools/xenstore/hashtable.c +++ b/tools/xenstore/hashtable.c @@ -141,11 +141,34 @@ static int hashtable_expand(struct hashtable *h) return 0; } +static struct entry *hashtable_search_entry(const struct hashtable *h, + const void *k) +{ + struct entry *e; + unsigned int hashvalue, index; + + hashvalue = hash(h, k); + index = indexFor(h->tablelength, hashvalue); + e = h->table[index]; + + for (e = h->table[index]; e; e = e->next) + { + /* Check hash value to short circuit heavier comparison */ + if ((hashvalue == e->h) && (h->eqfn(k, e->k))) + return e; + } + + return NULL; +} + int hashtable_add(struct hashtable *h, const void *k, void *v) { - /* This method allows duplicate keys - but they shouldn't be used */ unsigned int index; struct entry *e; + + if (hashtable_search_entry(h, k)) + return EEXIST; + if (++(h->entrycount) > h->loadlimit) { /* Ignore the return value. If expand fails, we should @@ -176,17 +199,10 @@ int hashtable_add(struct hashtable *h, const void *k, void *v) void *hashtable_search(const struct hashtable *h, const void *k) { struct entry *e; - unsigned int hashvalue, index; - hashvalue = hash(h,k); - index = indexFor(h->tablelength,hashvalue); - e = h->table[index]; - while (NULL != e) - { - /* Check hash value to short circuit heavier comparison */ - if ((hashvalue == e->h) && (h->eqfn(k, e->k))) return e->v; - e = e->next; - } - return NULL; + + e = hashtable_search_entry(h, k); + + return e ? e->v : NULL; } void diff --git a/tools/xenstore/hashtable.h b/tools/xenstore/hashtable.h index 792f6cda7b..e208d439a2 100644 --- a/tools/xenstore/hashtable.h +++ b/tools/xenstore/hashtable.h @@ -40,12 +40,6 @@ create_hashtable(const void *ctx, const char *name, * * This function will cause the table to expand if the insertion would take * the ratio of entries to table size over the maximum load factor. - * - * This function does not check for repeated insertions with a duplicate key. - * The value returned when using a duplicate key is undefined -- when - * the hashtable changes size, the order of retrieval of duplicate key - * entries is reversed. - * If in doubt, remove before insert. */ int -- generated by git-patchbot for /home/xen/git/xen.git#master
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