From ead340a66039096c7b4bf12dcd65e189769c6653 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Mon, 18 Oct 2021 17:51:11 -0700
Subject: feat(rc): job control prototype working for basic commands

---
 sys/cmd/rc/wait.c | 210 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 210 insertions(+)

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

diff --git a/sys/cmd/rc/wait.c b/sys/cmd/rc/wait.c
index 06f9614..db586cb 100644
--- a/sys/cmd/rc/wait.c
+++ b/sys/cmd/rc/wait.c
@@ -1,3 +1,213 @@
 #include "rc.h"
+
 #include <sys/wait.h>
 
+// -----------------------------------------------------------------------
+// globals
+
+struct WaitMsg
+{
+    int pid;
+    ulong time[3];
+    int status;
+    int signal;
+    int suspend;
+};
+
+
+// -----------------------------------------------------------------------
+// internal
+
+static
+int
+await(int pid4, int opt, struct WaitMsg *msg)
+{
+    int pid, status, core;
+    struct rusage ru;
+    ulong u, s;
+
+    /* event loop */
+    for(;;){
+        if((pid = wait4(pid4, &status, opt, &ru)) <= 0){
+            msg->pid = 0;
+            perror("failed wait");
+            return 0;
+        }
+
+        u = ru.ru_utime.tv_sec*1000+((ru.ru_utime.tv_usec+500)/1000);
+        s = ru.ru_stime.tv_sec*1000+((ru.ru_stime.tv_usec+500)/1000);
+
+        if(WIFEXITED(status)){
+            msg->pid     = pid;
+            msg->time[0] = u;
+            msg->time[1] = s;
+            msg->time[2] = u+s;
+            msg->status  = WEXITSTATUS(status);
+            msg->signal  = 0;
+            msg->suspend = 0;
+
+            return 1;
+        }
+
+        if(WIFSIGNALED(status)){
+            msg->pid     = pid;
+            msg->time[0] = u;
+            msg->time[1] = s;
+            msg->time[2] = u+s;
+            msg->status  = WCOREDUMP(status);
+            msg->signal  = 1;
+            msg->suspend = 0;
+
+            return 1;
+        }
+
+        if(WIFSTOPPED(status)){
+            msg->pid     = pid;
+            msg->time[0] = u;
+            msg->time[1] = s;
+            msg->time[2] = u+s;
+            msg->status  = WSTOPSIG(status);
+            msg->signal  = 0;
+            msg->suspend = 1;
+
+            return 1;
+        }
+    }
+}
+
+// -----------------------------------------------------------------------
+// exported
+
+void
+clearwait(Thread *job)
+{
+    job->wait.len = 0;
+}
+
+int
+havewait(Thread *job, int pid)
+{
+    int i;
+
+    for(i=0; i<job->wait.len; i++)
+        if(job->wait.pid[i] == pid)
+            return 1;
+    return 0;
+}
+
+void
+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.pid[job->wait.len++] = pid;
+}
+
+void
+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];
+    }
+    job->wait.len = w;
+}
+
+int
+waitall(Thread *job)
+{
+    Thread *t;
+    struct WaitMsg msg;
+
+    while(job->wait.len && await(-job->pgid, WUNTRACED, &msg)){
+        if(msg.pid == 0 && errno == ECHILD){
+            perror("wait job");
+            return 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);
+                    }
+                }
+                delwait(t, msg.pid);
+                goto outer;
+            }
+        }
+
+        perror("waitpid");
+        return 0;
+    outer:;
+    }
+
+    return 1;
+}
+
+void
+killzombies(void)
+{
+    Thread *job;
+    int index, status, pid;
+
+    while((pid=waitpid(-1, &status, WNOHANG))>0){
+        print(errio, "pid %d\n", pid);
+        flush(errio);
+
+        job = getjob(pid, &index);
+        if(!job){
+            perror("invalid pid");
+        }
+
+        job->flag.done = job->flag.stop = job->flag.again = 0;
+
+        if(WIFEXITED(status))
+            job->flag.done = 1;
+        if(WIFSTOPPED(status))
+            job->flag.stop = 1;
+        if(WIFCONTINUED(status))
+            job->flag.again = 1;
+
+        if(job->flag.done){
+            report(job,index);
+            deljob(job);
+        }
+    }
+}
+
+#if 0
+int
+waitfor(int pid)
+{
+    Thread *t;
+    struct WaitMsg w;
+
+    if(pid >= 0 && !havewait(pid))
+        return 0;
+
+    while(await(-proc->pgid, WUNTRACED, &w)){
+        delwait(w.pid);
+        if(w.pid == pid){
+            if(w.signal)
+                print(errio, "pid[%d]: signal: %d\n", w.pid, w.status);
+            return 1;
+        }
+        for(t=proc->link; t; t=t->link){
+            if(t->pid == w.pid)
+                t->pid = -1;
+        }
+    }
+
+    return 0;
+}
+#endif
-- 
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