From 61d7788b83b302207a67b82786f4fd79e3538f30 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Thu, 27 Jun 2019 11:10:43 +0200 Subject: Don't crash when RLIMIT_NOFILE is set to RLIM_INFINITY * src/safe.c (min_cached_fds): Define minimum number of cached dir file descriptors. (max_cached_fds): Change type to rlim_t to allow storing RLIM_INFINITY. (init_dirfd_cache): Set max_cached_fds to RLIM_INFINITY when RLIMIT_NOFILE is RLIM_INFINITY. Set the initial hash table size to min_cached_fds, independent of RLIMIT_NOFILE: patches commonly only affect one or a few files, so a small hash table will usually suffice; if needed, the hash table will grow. (insert_cached_dirfd): Don't shrink the cache when max_cached_fds is RLIM_INFINITY. --- src/safe.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/src/safe.c b/src/safe.c index 5a7202f..f147b0e 100644 --- a/src/safe.c +++ b/src/safe.c @@ -67,7 +67,8 @@ struct cached_dirfd { }; static Hash_table *cached_dirfds = NULL; -static size_t max_cached_fds; +static rlim_t min_cached_fds = 8; +static rlim_t max_cached_fds; LIST_HEAD (lru_list); static size_t hash_cached_dirfd (const void *entry, size_t table_size) @@ -98,11 +99,17 @@ static void init_dirfd_cache (void) { struct rlimit nofile; - max_cached_fds = 8; if (getrlimit (RLIMIT_NOFILE, &nofile) == 0) - max_cached_fds = MAX (nofile.rlim_cur / 4, max_cached_fds); + { + if (nofile.rlim_cur == RLIM_INFINITY) + max_cached_fds = RLIM_INFINITY; + else + max_cached_fds = MAX (nofile.rlim_cur / 4, min_cached_fds); + } + else + max_cached_fds = min_cached_fds; - cached_dirfds = hash_initialize (max_cached_fds, + cached_dirfds = hash_initialize (min_cached_fds, NULL, hash_cached_dirfd, compare_cached_dirfds, @@ -148,20 +155,23 @@ static void insert_cached_dirfd (struct cached_dirfd *entry, int keepfd) if (cached_dirfds == NULL) init_dirfd_cache (); - /* Trim off the least recently used entries */ - while (hash_get_n_entries (cached_dirfds) >= max_cached_fds) + if (max_cached_fds != RLIM_INFINITY) { - struct cached_dirfd *last = - list_entry (lru_list.prev, struct cached_dirfd, lru_link); - if (&last->lru_link == &lru_list) - break; - if (last->fd == keepfd) + /* Trim off the least recently used entries */ + while (hash_get_n_entries (cached_dirfds) >= max_cached_fds) { - last = list_entry (last->lru_link.prev, struct cached_dirfd, lru_link); + struct cached_dirfd *last = + list_entry (lru_list.prev, struct cached_dirfd, lru_link); if (&last->lru_link == &lru_list) break; + if (last->fd == keepfd) + { + last = list_entry (last->lru_link.prev, struct cached_dirfd, lru_link); + if (&last->lru_link == &lru_list) + break; + } + remove_cached_dirfd (last); } - remove_cached_dirfd (last); } /* Only insert if the parent still exists. */ -- cgit v1.0-41-gc330