Remove unused trace_clock_frequency

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

diff --git a/liblttng-ust/tracepoint.c b/liblttng-ust/tracepoint.c
index 0393aa467a282b17139a05ae17fd8336e7271fb9..a71e3e6e3967ea59bee850fe717fadad08b1669a 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
@@ -511,6 +524,20 @@ static void new_tracepoints(struct tracepoint * const *start, struct tracepoint
        }
 }
 
+static
+void lib_disable_tracepoints(struct tracepoint * const *begin,
+                       struct tracepoint * const *end)
+{
+       struct tracepoint * const *iter;
+
+       for (iter = begin; iter < end; iter++) {
+               if (!*iter)
+                       continue;       /* skip dummy */
+               disable_tracepoint(*iter);
+       }
+
+}
+
 int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
                            int tracepoints_count)
 {
@@ -553,18 +580,34 @@ lib_added:
 int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start)
 {
        struct tracepoint_lib *lib;
+       int tracepoints_count;
 
        ust_lock();
        cds_list_for_each_entry(lib, &libs, list) {
                if (lib->tracepoints_start == tracepoints_start) {
                        struct tracepoint_lib *lib2free = lib;
+
                        cds_list_del(&lib->list);
+                       tracepoints_count = lib->tracepoints_count;
                        free(lib2free);
-                       break;
+                       goto found;
                }
        }
+       goto end;
+found:
+       /*
+        * Force tracepoint disarm for all tracepoints of this lib.
+        * This takes care of destructor of library that would leave a
+        * LD_PRELOAD wrapper override function enabled for tracing, but
+        * the session teardown would not be able to reach the
+        * tracepoint anymore to disable it.
+        */
+       lib_disable_tracepoints(tracepoints_start,
+                       tracepoints_start + tracepoints_count);
+       DBG("just unregistered a tracepoints section from %p",
+               tracepoints_start);
+end:
        ust_unlock();
-
        return 0;
 }