--- freem/src/jobtab.c	2025/05/12 18:18:00	1.10
+++ freem/src/jobtab.c	2025/05/14 12:22:04	1.11
@@ -1,5 +1,5 @@
 /*
- *   $Id: jobtab.c,v 1.10 2025/05/12 18:18:00 snw Exp $
+ *   $Id: jobtab.c,v 1.11 2025/05/14 12:22:04 snw Exp $
  *    job table implementation
  *
  *  
@@ -24,6 +24,9 @@
  *   along with FreeM.  If not, see <https://www.gnu.org/licenses/>.
  *
  *   $Log: jobtab.c,v $
+ *   Revision 1.11  2025/05/14 12:22:04  snw
+ *   Further work on shared memory
+ *
  *   Revision 1.10  2025/05/12 18:18:00  snw
  *   Further work on shared memory
  *
@@ -118,23 +121,27 @@ short jobtab_get_sem(void)
     int tries;
     struct sembuf s = {0, -1, IPC_NOWAIT};
 
+    logprintf (FM_LOG_DEBUG, "jobtab_get_sem:  attempting to acquire job table semaphore");
+    
     if (have_jobtab_sem) {
+        logprintf (FM_LOG_DEBUG, "jobtab_get_sem:  acquired semaphore by virtue of already owning it");
         return TRUE;
     }
     
     for (tries = 0; tries < 5; tries++) {
 
         if (semop (semid_jobtab, &s, 1) != -1) {
+            logprintf (FM_LOG_DEBUG, "jobtab_get_sem:  acquired semaphore by virtue of calling semop on it");
             have_jobtab_sem = TRUE;           
             return TRUE;
         }
-
-        logprintf (FM_LOG_INFO, "jobtab_get_sem:  sleeping for retry [tries = %d]", tries);
+        
+        logprintf (FM_LOG_INFO, "jobtab_get_sem:  sleeping for retry [tries = %d; errno = %d; error = %s]", tries, errno, strerror (errno));
         sleep (1);
 
     }
     logprintf (FM_LOG_ERROR, "jobtab_get_sem:  failed to acquire job table semaphore");
-    
+
     have_jobtab_sem = FALSE;
     return FALSE;
 }
@@ -143,9 +150,14 @@ void jobtab_release_sem(void)
 {
     struct sembuf s = {0, 1, 0};
 
-    semop (semid_jobtab, &s, 1);
-
-    have_jobtab_sem = FALSE;
+    logprintf (FM_LOG_DEBUG, "jobtab_release_sem:  trying to release job table semaphore");
+    if (semop (semid_jobtab, &s, 1) != -1) {
+        logprintf (FM_LOG_DEBUG, "jobtab_release_sem:   released job table semaphore by means of semop");
+        have_jobtab_sem = FALSE;
+    }
+    else {        
+        logprintf (FM_LOG_FATAL, "jobtab_release_sem:  failed to release job table semaphore (error code %d [%s])", errno, strerror (errno));
+    }
 }
 
 
@@ -222,7 +234,7 @@ void job_remove(const pid_t pid)
 
     while ((t != NULL) && (t->pid != pid)) {
         p = t;
-        t = SBA(t->next);
+        t = SOA(t->next);
     }
 
     if (t == NULL) {
@@ -273,7 +285,7 @@ void job_set_ecode(const pid_t target_pi
         logprintf (FM_LOG_FATAL, "job_set_ecode:  failed to get job table semaphore");
     }
     
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
 
         if (s->pid == target_pid) {
             strncpy (s->last_ecode, ecode, 20);
@@ -292,7 +304,7 @@ pid_t job_stop_requested (const pid_t ta
 
     job_slot_t *s;
     
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
         if (s->pid == target_pid) {
             return s->stop_requested;
         }
@@ -308,7 +320,7 @@ void job_request_all_stop(void)
     job_slot_t *s;
 
     
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
 
         if ((s->flags & JFLG_DAEMON) != JFLG_DAEMON) {
             job_request_stop (s->pid);
@@ -324,7 +336,7 @@ void job_signal_all(const int sig)
 
     job_slot_t *s;
 
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
 
         if ((s->flags & JFLG_DAEMON) != JFLG_DAEMON) {
             kill (s->pid, sig);
@@ -341,7 +353,7 @@ int job_count(void)
     job_slot_t *s;
     int ct = 0;
 
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
 
         if ((s->flags & JFLG_DEFUNCT) != JFLG_DEFUNCT) {
             ct++;
@@ -362,7 +374,7 @@ job_slot_t *job_set_status(const pid_t t
         logprintf (FM_LOG_FATAL, "job_set_status:  failed to get job table semaphore");
     }    
     
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
 
         if (s->pid == target_pid) {
             s->status = status;
@@ -388,8 +400,8 @@ void job_gc_mark(void)
         logprintf (FM_LOG_FATAL, "job_gc_mark:  failed to get job table semaphore");
     }
 
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
-       
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
+        logprintf (FM_LOG_WARNING, "job_gc_mark looking at pid %ld", s->pid);
         if ((jobstat = kill (s->pid, 0)) != 0) {
             
             switch (jobstat) {
@@ -442,7 +454,7 @@ void job_gc_sweep(void)
     }
 
     
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
 
         if ((s->flags & JFLG_DEFUNCT) == JFLG_DEFUNCT) {
 
@@ -482,7 +494,7 @@ ipc_slot_t *job_send_ipc(const pid_t rec
     }
 
     
-    for (j = shm_config->hdr->jobtab_head; j != NULL; j = j->next) {
+    for (j = SOA(shm_config->hdr->jobtab_head); j != NULL; j = SOA(j->next)) {
 
         if (j->pid == receiver_pid) {
             
@@ -514,7 +526,7 @@ job_slot_t *job_get(const pid_t target_p
     
     job_slot_t *s;
 
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
         if (s->pid == target_pid) return s;        
     }
 
@@ -536,7 +548,7 @@ void job_dump(void)
     printf ("%-10s%-15s%-20s%-22s%s\r\n", "PID", "STATUS", "LAST ECODE", "STARTED", "FLAGS");
     printf ("%-10s%-15s%-20s%-22s%s\r\n", "---", "------", "----------", "-------", "-----");
     
-    for (s = shm_config->hdr->jobtab_head; s != NULL; s = s->next) {
+    for (s = SOA(shm_config->hdr->jobtab_head); s != NULL; s = SOA(s->next)) {
 
         strftime (time_buf, 20, "%Y-%m-%d %H:%M:%S", localtime (&(s->start_time)));