Print compiler warning/runtime warning and truncate too long tracepoint names

[lttng-ust.git] / liblttng-ust / tracepoint.c

diff --git a/liblttng-ust/tracepoint.c b/liblttng-ust/tracepoint.c
index 0393aa467a282b17139a05ae17fd8336e7271fb9..f146d382b7717955875938a1169d8436515ee043 100644 (file)
--- a/liblttng-ust/tracepoint.c
+++ b/liblttng-ust/tracepoint.c
@@ -31,6 +31,7 @@
 #include <urcu/compiler.h>
 
 #include <lttng/tracepoint.h>
+#include <lttng/ust-abi.h>     /* for LTTNG_UST_SYM_NAME_LEN */
 
 #include <usterr-signal-safe.h>
 #include <helper.h>
@@ -207,11 +208,17 @@ static struct tracepoint_entry *get_tracepoint(const char *name)
        struct cds_hlist_head *head;
        struct cds_hlist_node *node;
        struct tracepoint_entry *e;
-       uint32_t hash = jhash(name, strlen(name), 0);
+       size_t name_len = strlen(name);
+       uint32_t hash;
 
+       if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) {
+               WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1);
+               name_len = LTTNG_UST_SYM_NAME_LEN - 1;
+       }
+       hash = jhash(name, name_len, 0);
        head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
        cds_hlist_for_each_entry(e, node, head, hlist) {
-               if (!strcmp(name, e->name))
+               if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1))
                        return e;
        }
        return NULL;
@@ -226,12 +233,17 @@ static struct tracepoint_entry *add_tracepoint(const char *name)
        struct cds_hlist_head *head;
        struct cds_hlist_node *node;
        struct tracepoint_entry *e;
-       size_t name_len = strlen(name) + 1;
-       uint32_t hash = jhash(name, name_len-1, 0);
+       size_t name_len = strlen(name);
+       uint32_t hash;
 
+       if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) {
+               WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1);
+               name_len = LTTNG_UST_SYM_NAME_LEN - 1;
+       }
+       hash = jhash(name, name_len, 0);
        head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
        cds_hlist_for_each_entry(e, node, head, hlist) {
-               if (!strcmp(name, e->name)) {
+               if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) {
                        DBG("tracepoint %s busy", name);
                        return ERR_PTR(-EEXIST);        /* Already there */
                }
@@ -240,10 +252,11 @@ static struct tracepoint_entry *add_tracepoint(const char *name)
         * Using zmalloc here to allocate a variable length element. Could
         * cause some memory fragmentation if overused.
         */
-       e = zmalloc(sizeof(struct tracepoint_entry) + name_len);
+       e = zmalloc(sizeof(struct tracepoint_entry) + name_len + 1);
        if (!e)
                return ERR_PTR(-ENOMEM);
-       memcpy(&e->name[0], name, name_len);
+       memcpy(&e->name[0], name, name_len + 1);
+       e->name[name_len] = '\0';
        e->probes = NULL;
        e->refcount = 0;
        cds_hlist_add_head(&e->hlist, head);
@@ -266,7 +279,7 @@ static void remove_tracepoint(struct tracepoint_entry *e)
 static void set_tracepoint(struct tracepoint_entry **entry,
        struct tracepoint *elem, int active)
 {
-       WARN_ON(strcmp((*entry)->name, elem->name) != 0);
+       WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_SYM_NAME_LEN - 1) != 0);
 
        /*
         * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new