From 47e3d475df6244a48b73421cd4210b64c392df8d Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Tue, 19 Oct 2021 09:35:59 -0700
Subject: feat(rc): cleaner process watching for each job

---
 sys/cmd/rc/wait.c | 94 +++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 64 insertions(+), 30 deletions(-)

(limited to 'sys/cmd/rc/wait.c')

diff --git a/sys/cmd/rc/wait.c b/sys/cmd/rc/wait.c
index db586cb..44ffb58 100644
--- a/sys/cmd/rc/wait.c
+++ b/sys/cmd/rc/wait.c
@@ -8,13 +8,11 @@
 struct WaitMsg
 {
     int pid;
+    int type;
     ulong time[3];
     int status;
-    int signal;
-    int suspend;
 };
 
-
 // -----------------------------------------------------------------------
 // internal
 
@@ -30,7 +28,7 @@ await(int pid4, int opt, struct WaitMsg *msg)
     for(;;){
         if((pid = wait4(pid4, &status, opt, &ru)) <= 0){
             msg->pid = 0;
-            perror("failed wait");
+            perror("failed wait4");
             return 0;
         }
 
@@ -43,8 +41,7 @@ await(int pid4, int opt, struct WaitMsg *msg)
             msg->time[1] = s;
             msg->time[2] = u+s;
             msg->status  = WEXITSTATUS(status);
-            msg->signal  = 0;
-            msg->suspend = 0;
+            msg->type    = PDone;
 
             return 1;
         }
@@ -55,8 +52,7 @@ await(int pid4, int opt, struct WaitMsg *msg)
             msg->time[1] = s;
             msg->time[2] = u+s;
             msg->status  = WCOREDUMP(status);
-            msg->signal  = 1;
-            msg->suspend = 0;
+            msg->type    = PSig;
 
             return 1;
         }
@@ -67,14 +63,27 @@ await(int pid4, int opt, struct WaitMsg *msg)
             msg->time[1] = s;
             msg->time[2] = u+s;
             msg->status  = WSTOPSIG(status);
-            msg->signal  = 0;
-            msg->suspend = 1;
+            msg->type    = PStop;
 
             return 1;
         }
     }
 }
 
+static
+int
+shouldwait(Thread *job)
+{
+    int i;
+
+    for(i=0; i<job->wait.len; i++){
+        if(job->wait.on[i].status == PRun)
+            return 1;
+    }
+
+    return 0;
+}
+
 // -----------------------------------------------------------------------
 // exported
 
@@ -90,7 +99,7 @@ havewait(Thread *job, int pid)
     int i;
 
     for(i=0; i<job->wait.len; i++)
-        if(job->wait.pid[i] == pid)
+        if(job->wait.on[i].pid == pid)
             return 1;
     return 0;
 }
@@ -100,9 +109,10 @@ addwait(Thread *job, int pid)
 {
     if(job->wait.len == job->wait.cap){
         job->wait.cap = job->wait.cap + 2;
-        job->wait.pid = erealloc(job->wait.pid, job->wait.cap*sizeof(*job->wait.pid));
+        job->wait.on  = erealloc(job->wait.on, job->wait.cap*sizeof(*job->wait.on));
     }
-    job->wait.pid[job->wait.len++] = pid;
+
+    job->wait.on[job->wait.len++] = (struct WaitItem){.pid=pid, .status=PRun};
 }
 
 void
@@ -111,8 +121,8 @@ delwait(Thread *job, int pid)
     int r, w;
 
     for(r=w=0; r < job->wait.len; r++){
-        if(job->wait.pid[r] != pid)
-            job->wait.pid[w++] = job->wait.pid[r];
+        if(job->wait.on[r].pid != pid)
+            job->wait.on[w++].pid = job->wait.on[r].pid;
     }
     job->wait.len = w;
 }
@@ -120,36 +130,63 @@ delwait(Thread *job, int pid)
 int
 waitall(Thread *job)
 {
+    int i;
     Thread *t;
     struct WaitMsg msg;
 
-    while(job->wait.len && await(-job->pgid, WUNTRACED, &msg)){
-        if(msg.pid == 0 && errno == ECHILD){
+    while(shouldwait(job) && await(-job->pgid, WUNTRACED, &msg)){
+        if(msg.pid == 0){
             perror("wait job");
             return 0;
         }
 
+        for(i=0; i < job->wait.len; i++){
+            if(job->wait.on[i].pid == msg.pid){
+                switch(msg.type){
+                case PStop:
+                    print(shell.err, "%d: suspended\n", msg.pid);
+                    job->wait.status = PStop;
+                    job->wait.on[i].status = PStop;
+                    break;
+
+                case PSig:
+                    print(shell.err, "%d: terminated by signal %d\n", msg.pid, msg.status);
+                    /* fallthrough */
+                case PDone:
+                    job->wait.on[i].status = PDone;
+                    delwait(job, msg.pid);
+                    if(!job->wait.len)
+                        job->wait.status = PDone;
+                    break;
+
+                default:
+                    fatal("%d: unrecognized message type %d\n", msg.pid, msg.type);
+                }
+                break;
+            }
+        }
+    }
+#if 0
         for(t=job; t; t=t->link){
             if(t->pid == msg.pid){
                 t->status = msg.status;
-                t->flag.stop = t->flag.done = t->flag.again = 0;
                 if(msg.suspend){
                     t->flag.stop = 1;
                 }else{
                     t->flag.done = 1;
                     if(msg.signal){
-                        print(errio, "%d: terminated by signal %d\n", msg.pid, msg.status);
+                        print(shell.err, "%d: terminated by signal %d\n", msg.pid, msg.status);
                     }
                 }
                 delwait(t, msg.pid);
                 goto outer;
             }
         }
-
         perror("waitpid");
         return 0;
     outer:;
     }
+#endif
 
     return 1;
 }
@@ -161,24 +198,21 @@ killzombies(void)
     int index, status, pid;
 
     while((pid=waitpid(-1, &status, WNOHANG))>0){
-        print(errio, "pid %d\n", pid);
-        flush(errio);
+        print(shell.err, "found zombie pid %d\n", pid);
+        flush(shell.err);
 
         job = getjob(pid, &index);
-        if(!job){
+        if(!job)
             perror("invalid pid");
-        }
-
-        job->flag.done = job->flag.stop = job->flag.again = 0;
 
         if(WIFEXITED(status))
-            job->flag.done = 1;
+            job->wait.status = PDone;
         if(WIFSTOPPED(status))
-            job->flag.stop = 1;
+            job->wait.status = PStop;
         if(WIFCONTINUED(status))
-            job->flag.again = 1;
+            job->wait.status = PAgain;
 
-        if(job->flag.done){
+        if(job->wait.status == PDone){
             report(job,index);
             deljob(job);
         }
-- 
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