Add libuv thread names support to FATAL log level (#9382)

* Add support for the fatal() family of calls to detect non-netdata thread names from the OS

configure.ac

@@ -265,6 +265,12 @@ LIBS="${PTHREAD_LIBS} ${LIBS}"
 CFLAGS="${CFLAGS} ${PTHREAD_CFLAGS}"
 CC="${PTHREAD_CC}"
 
+AC_CHECK_LIB(
+[pthread],
+[pthread_getname_np],
+[AC_DEFINE([HAVE_PTHREAD_GETNAME_NP], [1], [Is set if pthread_getname_np is available])]
+)
+
 
 # -----------------------------------------------------------------------------
 # libm

libnetdata/log/log.c

@@ -796,6 +796,8 @@ void fatal_int( const char *file, const char *function, const unsigned long line
     // save a copy of errno - just in case this function generates a new error
     int __errno = errno;
     va_list args;
+    const char *thread_tag;
+    char os_threadname[NETDATA_THREAD_NAME_MAX + 1];
 
     if(error_log_syslog) {
         va_start( args, fmt );
@@ -803,14 +805,22 @@ void fatal_int( const char *file, const char *function, const unsigned long line
         va_end( args );
     }
 
+    thread_tag = netdata_thread_tag();
+    if (!netdata_thread_tag_exists()) {
+        os_thread_get_current_name_np(os_threadname);
+        if ('\0' != os_threadname[0]) { /* If it is not an empty string replace "MAIN" thread_tag */
+            thread_tag = os_threadname;
+        }
+    }
+
     char date[LOG_DATE_LENGTH];
     log_date(date, LOG_DATE_LENGTH);
 
     log_lock();
 
     va_start( args, fmt );
-    if(debug_flags) fprintf(stderr, "%s: %s FATAL : %s : (%04lu@%-10.10s:%-15.15s): ", date, program_name, netdata_thread_tag(), line, file, function);
-    else            fprintf(stderr, "%s: %s FATAL : %s :", date, program_name, netdata_thread_tag());
+    if(debug_flags) fprintf(stderr, "%s: %s FATAL : %s : (%04lu@%-10.10s:%-15.15s): ", date, program_name, thread_tag, line, file, function);
+    else            fprintf(stderr, "%s: %s FATAL : %s : ", date, program_name, thread_tag);
     vfprintf( stderr, fmt, args );
     va_end( args );
 
@@ -823,7 +833,7 @@ void fatal_int( const char *file, const char *function, const unsigned long line
     snprintfz(action_data, 70, "%04lu@%-10.10s:%-15.15s/%d", line, file, function, __errno);
     char action_result[60+1];
 
-    snprintfz(action_result, 60, "%s:%s", program_name, strncmp(netdata_thread_tag(), "STREAM_RECEIVER", strlen("STREAM_RECEIVER"))?netdata_thread_tag():"[x]");
+    snprintfz(action_result, 60, "%s:%s", program_name, strncmp(thread_tag, "STREAM_RECEIVER", strlen("STREAM_RECEIVER")) ? thread_tag : "[x]");
     send_statistics("FATAL", action_result, action_data);
 
     netdata_cleanup_and_exit(1);

libnetdata/threads/threads.c

@@ -18,8 +18,12 @@ typedef struct {
 
 static __thread NETDATA_THREAD *netdata_thread = NULL;
 
+inline int netdata_thread_tag_exists(void) {
+    return (netdata_thread && netdata_thread->tag && *netdata_thread->tag);
+}
+
 const char *netdata_thread_tag(void) {
-    return ((netdata_thread && netdata_thread->tag && *netdata_thread->tag)?netdata_thread->tag:"MAIN");
+    return (netdata_thread_tag_exists() ? netdata_thread->tag : "MAIN");
 }
 
 // ----------------------------------------------------------------------------
@@ -151,6 +155,18 @@ void uv_thread_set_name_np(uv_thread_t ut, const char* name) {
         info("cannot set libuv thread name to %s. Err: %d", threadname, ret);
 }
 
+void os_thread_get_current_name_np(char threadname[NETDATA_THREAD_NAME_MAX + 1])
+{
+    int ret = 0;
+
+    threadname[0] = '\0';
+#if defined(__FreeBSD__)
+    pthread_get_name_np(pthread_self(), threadname, NETDATA_THREAD_NAME_MAX + 1);
+#elif defined(HAVE_PTHREAD_GETNAME_NP) /* Linux & macOS */
+    (void)pthread_getname_np(pthread_self(), threadname, NETDATA_THREAD_NAME_MAX + 1);
+#endif
+}
+
 static void *thread_start(void *ptr) {
     netdata_thread = (NETDATA_THREAD *)ptr;
 

libnetdata/threads/threads.h

@@ -22,6 +22,7 @@ typedef pthread_t netdata_thread_t;
 
 #define NETDATA_THREAD_TAG_MAX 100
 extern const char *netdata_thread_tag(void);
+extern int netdata_thread_tag_exists(void);
 
 extern size_t netdata_threads_init(void);
 extern void netdata_threads_init_after_fork(size_t stacksize);
@@ -33,6 +34,7 @@ extern int netdata_thread_detach(pthread_t thread);
 
 #define NETDATA_THREAD_NAME_MAX 15
 extern void uv_thread_set_name_np(uv_thread_t ut, const char* name);
+extern void os_thread_get_current_name_np(char threadname[NETDATA_THREAD_NAME_MAX + 1]);
 
 #define netdata_thread_self pthread_self
 #define netdata_thread_testcancel pthread_testcancel