Terminate background thread gracefully (#424)

* Terminate background thread gracefully * fix background thread pause/resume action naming
Tlf · Feb 7, 2024 · ffb8e0f · ffb8e0f
1 parent d632426
commit ffb8e0f
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Showing 6 changed files with 42 additions and 34 deletions.
diff --git a/src/background_process.c b/src/background_process.c
@@ -41,38 +41,44 @@
 #include "tlf.h"
 #include "write_keyer.h"
 
+static bool go = true;
 // don't start until we know what we are doing
-static bool stop_backgrnd_process = true;
-
-static pthread_mutex_t stop_backgrnd_process_mutex = PTHREAD_MUTEX_INITIALIZER;
-static pthread_cond_t start_backgrnd_process_cond = PTHREAD_COND_INITIALIZER;
-static pthread_cond_t backgrnd_process_stopped_cond = PTHREAD_COND_INITIALIZER;
-
-void stop_background_process(void) {
-    pthread_mutex_lock(&stop_backgrnd_process_mutex);
-    assert(!stop_backgrnd_process);
-    stop_backgrnd_process = true;
-    pthread_cond_wait(&backgrnd_process_stopped_cond, &stop_backgrnd_process_mutex);
-    pthread_mutex_unlock(&stop_backgrnd_process_mutex);
+static bool pause_backgrnd_process = true;
+
+static pthread_mutex_t pause_backgrnd_process_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t resume_backgrnd_process_cond = PTHREAD_COND_INITIALIZER;
+static pthread_cond_t backgrnd_process_paused_cond = PTHREAD_COND_INITIALIZER;
+
+void terminate_background_process() {
+    go = false;
 }
 
-void start_background_process(void) {
-    pthread_mutex_lock(&stop_backgrnd_process_mutex);
-    assert(stop_backgrnd_process);
-    stop_backgrnd_process = false;
-    pthread_cond_broadcast(&start_backgrnd_process_cond);
-    pthread_mutex_unlock(&stop_backgrnd_process_mutex);
+void pause_background_process(void) {
+    pthread_mutex_lock(&pause_backgrnd_process_mutex);
+    assert(!pause_backgrnd_process);
+    pause_backgrnd_process = true;
+    pthread_cond_wait(&backgrnd_process_paused_cond, &pause_backgrnd_process_mutex);
+    pthread_mutex_unlock(&pause_backgrnd_process_mutex);
+}
+
+void resume_background_process(void) {
+    pthread_mutex_lock(&pause_backgrnd_process_mutex);
+    assert(pause_backgrnd_process);
+    pause_backgrnd_process = false;
+    pthread_cond_broadcast(&resume_backgrnd_process_cond);
+    pthread_mutex_unlock(&pause_backgrnd_process_mutex);
 }
 
 static void background_process_wait(void) {
-    pthread_mutex_lock(&stop_backgrnd_process_mutex);
-    if (stop_backgrnd_process) {
-	pthread_cond_broadcast(&backgrnd_process_stopped_cond);
-	pthread_cond_wait(&start_backgrnd_process_cond, &stop_backgrnd_process_mutex);
+    pthread_mutex_lock(&pause_backgrnd_process_mutex);
+    if (pause_backgrnd_process) {
+	pthread_cond_broadcast(&backgrnd_process_paused_cond);
+	pthread_cond_wait(&resume_backgrnd_process_cond, &pause_backgrnd_process_mutex);
     }
-    pthread_mutex_unlock(&stop_backgrnd_process_mutex);
+    pthread_mutex_unlock(&pause_backgrnd_process_mutex);
 }
 
+
 void *background_process(void *ptr) {
 
     char *prmessage;
@@ -84,7 +90,7 @@ void *background_process(void *ptr) {
     char debugbuffer[160];
     FILE *fp;
 
-    while (1) {
+    while (go) {
 
 	background_process_wait();
 
@@ -120,7 +126,7 @@ void *background_process(void *ptr) {
 	    fldigi_rpc_cnt = 1 - fldigi_rpc_cnt;
 	}
 
-	if (!stop_backgrnd_process) {
+	if (!pause_backgrnd_process) {
 	    write_keyer();
 	    cqww_simulator();
 	}
@@ -150,7 +156,7 @@ void *background_process(void *ptr) {
 
 	    if ((*lan_message != '\0')
 		    && (lan_message[0] != thisnode)
-		    && !stop_backgrnd_process) {
+		    && !pause_backgrnd_process) {
 
 		switch (lan_message[1]) {
 
@@ -250,5 +256,6 @@ void *background_process(void *ptr) {
 
     }
 
+    pthread_exit(NULL);
 }
 
diff --git a/src/background_process.h b/src/background_process.h
@@ -23,7 +23,8 @@
 #define BACKGROUND_PROCESS_H
 
 void *background_process(void *);
-void stop_background_process(void);
-void start_background_process(void);
+void terminate_background_process();
+void pause_background_process(void);
+void resume_background_process(void);
 
 #endif /* end of include guard: BACKGROUND_PROCESS_H */
diff --git a/src/edit_last.c b/src/edit_last.c
@@ -201,7 +201,7 @@ void edit_last(void) {
     if (NR_QSOS == 0)
 	return;			/* nothing to edit */
 
-    stop_background_process();  // note: this freezes nr_qsos, as network is paused
+    pause_background_process();  // note: this freezes nr_qsos, as network is paused
 
     const int topline = (NR_LINES > NR_QSOS ? NR_LINES - NR_QSOS : 0);
 
@@ -333,5 +333,5 @@ void edit_last(void) {
 
     scroll_log();
 
-    start_background_process();
+    resume_background_process();
 }
diff --git a/src/editlog.c b/src/editlog.c
@@ -72,13 +72,13 @@ void edit(char *filename) {
 
 void logedit(void) {
 
-    stop_background_process();
+    pause_background_process();
     edit(logfile);
     checklogfile();
 
     log_read_n_score();
 
-    start_background_process();
+    resume_background_process();
 
     attron(COLOR_PAIR(C_LOG) | A_STANDOUT);
     erase();

diff --git a/src/logit.c b/src/logit.c
@@ -75,7 +75,7 @@ void logit(void) {
     clear_display();
     defer_store = 0;
 
-    start_background_process();	/* start it up */
+    resume_background_process();	/* start it up */
 
     while (1) {
 	printcall();

diff --git a/src/main.c b/src/main.c
@@ -962,7 +962,7 @@ static void mark_GPL_seen() {
  */
 static void tlf_cleanup() {
     if (pthread_self() != background_thread) {
-	pthread_cancel(background_thread);
+	terminate_background_process();
 	pthread_join(background_thread, NULL);
     }