Use destination buffer size for snprintf()

3 files changed, 19 insertions, 9 deletions

diff --git a/erts/emulator/beam/erl_async.c b/erts/emulator/beam/erl_async.c
index 536c50c283..cc42f68668 100644
--- a/erts/emulator/beam/erl_async.c
+++ b/erts/emulator/beam/erl_async.c
@@ -209,7 +209,7 @@ erts_init_async(void)
 	for (i = 0; i < erts_async_max_threads; i++) {
 	    ErtsAsyncQ *aq = async_q(i);
 
-            erts_snprintf(thr_opts.name, 32, "async_%d", i+1);
+            erts_snprintf(thr_opts.name, sizeof(thr_name), "async_%d", i+1);
 
 	    erts_thr_create(&aq->thr_id, async_main, (void*) aq, &thr_opts);
 	}
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 12de96f4e9..4a69900d28 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -8622,7 +8622,7 @@ erts_start_schedulers(void)
 
     if (erts_runq_supervision_interval) {
 	opts.suggested_stack_size = 16;
-        erts_snprintf(opts.name, 32, "runq_supervisor");
+        erts_snprintf(opts.name, sizeof(name), "runq_supervisor");
 	erts_atomic_init_nob(&runq_supervisor_sleeping, 0);
 	if (0 != ethr_event_init(&runq_supervision_event))
 	    erts_exit(ERTS_ABORT_EXIT, "Failed to create run-queue supervision event\n");
@@ -8643,7 +8643,7 @@ erts_start_schedulers(void)
     for (ix = 0; ix < erts_no_schedulers; ix++) {
 	ErtsSchedulerData *esdp = ERTS_SCHEDULER_IX(ix);
 	ASSERT(ix == esdp->no - 1);
-	erts_snprintf(opts.name, 32, "%lu_scheduler", ix + 1);
+	erts_snprintf(opts.name, sizeof(name), "%lu_scheduler", ix + 1);
 	res = ethr_thr_create(&esdp->tid, sched_thread_func, (void*)esdp, &opts);
 	if (res != 0) {
            erts_exit(ERTS_ABORT_EXIT, "Failed to create scheduler thread %d, error = %d\n", ix, res);
@@ -8657,7 +8657,7 @@ erts_start_schedulers(void)
     {
 	for (ix = 0; ix < erts_no_dirty_cpu_schedulers; ix++) {
 	    ErtsSchedulerData *esdp = ERTS_DIRTY_CPU_SCHEDULER_IX(ix);
-	    erts_snprintf(opts.name, 32, "%d_dirty_cpu_scheduler", ix + 1);
+	    erts_snprintf(opts.name, sizeof(name), "%d_dirty_cpu_scheduler", ix + 1);
             opts.suggested_stack_size = erts_dcpu_sched_thread_suggested_stack_size;
 	    res = ethr_thr_create(&esdp->tid,sched_dirty_cpu_thread_func,(void*)esdp,&opts);
 	    if (res != 0)
@@ -8665,7 +8665,7 @@ erts_start_schedulers(void)
 	}
 	for (ix = 0; ix < erts_no_dirty_io_schedulers; ix++) {
 	    ErtsSchedulerData *esdp = ERTS_DIRTY_IO_SCHEDULER_IX(ix);
-	    erts_snprintf(opts.name, 32, "%d_dirty_io_scheduler", ix + 1);
+	    erts_snprintf(opts.name, sizeof(name), "%d_dirty_io_scheduler", ix + 1);
             opts.suggested_stack_size = erts_dio_sched_thread_suggested_stack_size;
 	    res = ethr_thr_create(&esdp->tid,sched_dirty_io_thread_func,(void*)esdp,&opts);
 	    if (res != 0)
@@ -8673,14 +8673,14 @@ erts_start_schedulers(void)
 	}
     }
 
-    erts_snprintf(opts.name, 32, "aux");
+    erts_snprintf(opts.name, sizeof(name), "aux");
 
     res = ethr_thr_create(&tid, aux_thread, NULL, &opts);
     if (res != 0)
 	erts_exit(ERTS_ABORT_EXIT, "Failed to create aux thread, error = %d\n", res);
 
     for (ix = 0; ix < erts_no_poll_threads; ix++) {
-        erts_snprintf(opts.name, 32, "%d_poller", ix);
+        erts_snprintf(opts.name, sizeof(name), "%d_poller", ix);
 
         res = ethr_thr_create(&tid, poll_thread, (void*)(UWord)ix, &opts);
         if (res != 0)
diff --git a/erts/lib_src/pthread/ethread.c b/erts/lib_src/pthread/ethread.c
index 9dcc2c505d..ba36b2f452 100644
--- a/erts/lib_src/pthread/ethread.c
+++ b/erts/lib_src/pthread/ethread.c
@@ -341,11 +341,21 @@ ethr_thr_create(ethr_tid *tid, void * (*func)(void *), void *arg,
     twd.stacksize = 0;
 
     if (opts && opts->name) {
+        size_t nlen = sizeof(twd.name_buff);
 #ifdef __HAIKU__
-        snprintf(twd.name_buff, B_OS_NAME_LENGTH, "%s", opts->name);
+        if (nlen > B_OS_NAME_LENGTH)
+            nlen = B_OS_NAME_LENGTH;
 #else
-        snprintf(twd.name_buff, 16, "%s", opts->name);
+        /*
+         * Length of 16 is known to work. At least pthread_setname_np()
+         * is documented to fail on too long name string, but documentation
+         * does not say what the limit is. Do not have the time to dig
+         * further into that now...
+         */
+        if (nlen > 16)
+            nlen = 16;
 #endif
+        snprintf(twd.name_buff, nlen, "%s", opts->name);
 	twd.name = twd.name_buff;
     } else
         twd.name = NULL;