diff options
| -rw-r--r-- | lib/hostip.c | 71 |
1 files changed, 48 insertions, 23 deletions
diff --git a/lib/hostip.c b/lib/hostip.c index 80fa25a6b..42eebfe52 100644 --- a/lib/hostip.c +++ b/lib/hostip.c @@ -98,10 +98,18 @@ struct curl_dns_cache_entry { time_t timestamp; }; +/* count the number of characters that an integer takes up */ static int _num_chars(int i) { int chars = 0; + /* While the number divided by 10 is greater than one, + * re-divide the number by 10, and increment the number of + * characters by 1. + * + * this relies on the fact that for every multiple of 10, + * a new digit is added onto every number + */ do { chars++; @@ -111,21 +119,28 @@ static int _num_chars(int i) return chars; } +/* Create a hostcache id */ static char * -_create_hostcache_id(char *server, int server_len, int port) +_create_hostcache_id(char *server, int port, size_t *entry_len) { char *id = NULL; - int id_len; - id_len = server_len + _num_chars(port); - - id = malloc(id_len + 1); + /* Get the length of the new entry id */ + *entry_len = *entry_len + /* Hostname length */ + 1 + /* The ':' seperator */ + _num_chars(port); /* The number of characters the port will take up */ + + /* Allocate the new entry id */ + id = malloc(*entry_len + 1); if (!id) { return NULL; } - id_len = sprintf(id, "%s:%d", server, port); - if (id_len <= 0) { + /* Create the new entry */ + /* If sprintf() doesn't return the entry length, that signals failure */ + if (sprintf(id, "%s:%d", server, port) != *entry_len) { + /* Free the allocated id, set length to zero and return NULL */ + *entry_len = 0; free(id); return NULL; } @@ -133,16 +148,21 @@ _create_hostcache_id(char *server, int server_len, int port) return id; } - +/* Macro to save redundant free'ing of entry_id */ +#define _hostcache_return(__v) \ +{ \ + free(entry_id); \ + return (__v); \ +} Curl_addrinfo *Curl_resolv(struct SessionHandle *data, char *hostname, int port, char **bufp) { - char *cache_id = NULL; + char *entry_id = NULL; struct curl_dns_cache_entry *p = NULL; - size_t hostname_len; + size_t entry_len; time_t now; /* If the host cache timeout is 0, we don't do DNS cach'ing @@ -151,42 +171,47 @@ Curl_addrinfo *Curl_resolv(struct SessionHandle *data, return Curl_getaddrinfo(data, hostname, port, bufp); } - hostname_len = strlen(hostname); - - cache_id = _create_hostcache_id(hostname, hostname_len, port); + /* Create an entry id, based upon the hostname and port */ + entry_len = strlen(hostname); + entry_id = _create_hostcache_id(hostname, port, &entry_len); + /* If we can't create the entry id, don't cache, just fall-through + to the plain Curl_getaddrinfo() */ + if (!entry_id) { + return Curl_getaddrinfo(data, hostname, port, bufp); + } time(&now); /* See if its already in our dns cache */ - if (cache_id && curl_hash_find(data->hostcache, hostname, hostname_len+1, (void **) &p)) { + if (entry_id && curl_hash_find(data->hostcache, entry_id, entry_len+1, (void **) &p)) { /* Do we need to check for a cache timeout? */ if (data->set.dns_cache_timeout != -1) { /* Return if the entry has not timed out */ if ((now - p->timestamp) < data->set.dns_cache_timeout) { - return p->addr; + _hostcache_return(p->addr); } } else { - return p->addr; + _hostcache_return(p->addr); } } /* Create a new cache entry */ - p = (struct curl_dns_cache_entry *) - malloc(sizeof(struct curl_dns_cache_entry)); - if (!p) - return NULL; + p = (struct curl_dns_cache_entry *) malloc(sizeof(struct curl_dns_cache_entry)); + if (!p) { + _hostcache_return(NULL); + } p->addr = Curl_getaddrinfo(data, hostname, port, bufp); if (!p->addr) { free(p); - return NULL; + _hostcache_return(NULL); } p->timestamp = now; /* Save it in our host cache */ - curl_hash_update(data->hostcache, hostname, hostname_len+1, (const void *) p); + curl_hash_update(data->hostcache, entry_id, entry_len+1, (const void *) p); - return p->addr; + _hostcache_return(p->addr); } /* |