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-rw-r--r--lib/hostip.c71
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);
}
/*