From ce05175372a9ddca1a225db0765ace1127a39293 Mon Sep 17 00:00:00 2001
From: Nicholas <nbnoll@eml.cc>
Date: Fri, 12 Nov 2021 09:22:01 -0800
Subject: chore: simplified organizational structure

---
 src/cmd/rc/wait.c | 247 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 247 insertions(+)
 create mode 100644 src/cmd/rc/wait.c

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

diff --git a/src/cmd/rc/wait.c b/src/cmd/rc/wait.c
new file mode 100644
index 0000000..911601c
--- /dev/null
+++ b/src/cmd/rc/wait.c
@@ -0,0 +1,247 @@
+#include "rc.h"
+
+#include <sys/wait.h>
+
+// -----------------------------------------------------------------------
+// globals
+
+struct WaitMsg
+{
+    int pid;
+    int type;
+    ulong time[3];
+    int status;
+};
+
+// -----------------------------------------------------------------------
+// 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){
+            if(errno == ECHILD){
+                msg->pid = -1;
+                return 1;
+            }
+            msg->pid = 0;
+            perror("failed wait4");
+            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->type    = Pdone;
+
+            return 1;
+        }
+
+        if(WIFSIGNALED(status)){
+            msg->pid     = pid;
+            msg->time[0] = u;
+            msg->time[1] = s;
+            msg->time[2] = u+s;
+            msg->status  = WTERMSIG(status);
+            msg->type    = Psig;
+
+            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->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;
+}
+
+static inline
+void
+notify(Thread *job, struct WaitMsg msg)
+{
+    int i;
+    for(i=0; i < job->wait.len; i++){
+        if(job->wait.on[i].pid == msg.pid){
+            job->status = msg.status;
+            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;
+        }
+    }
+}
+
+// -----------------------------------------------------------------------
+// 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.on[i].pid == 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.on  = erealloc(job->wait.on, job->wait.cap*sizeof(*job->wait.on));
+    }
+
+    job->wait.on[job->wait.len++] = (struct WaitItem){.pid=pid, .status=Prun};
+}
+
+void
+delwait(Thread *job, int pid)
+{
+    int r, w;
+
+    for(r=w=0; r < job->wait.len; r++){
+        if(job->wait.on[r].pid != pid)
+            job->wait.on[w++].pid = job->wait.on[r].pid;
+    }
+    job->wait.len = w;
+}
+
+int
+waitall(Thread *job)
+{
+    int i;
+    Thread *t;
+    struct WaitMsg msg;
+
+    while(shouldwait(job) && await(-job->pgid, WUNTRACED, &msg)){
+        switch(msg.pid){
+        case 0:   // error
+            perror("wait job");
+            return 0;
+        case -1: // no children: assume they have exited
+            job->wait.status = Pdone;
+            clearwait(job);
+            return 1;
+        default:
+            ;
+        }
+
+        notify(job, msg);
+    }
+    return 1;
+}
+
+int
+waitfor(Thread *job, int pid)
+{
+    int i;
+    Thread *t;
+    struct WaitMsg msg;
+
+    while(shouldwait(job) && await(-job->pgid, WUNTRACED, &msg)){
+        switch(msg.pid){
+        case 0:   // error
+            perror("wait for");
+            return 0;
+        case -1: // no children: assume they have exited
+            job->wait.status = Pdone;
+            clearwait(job);
+            return 1;
+        default:
+            ;
+        }
+
+        notify(job, msg);
+        /* allow for an early exit */
+        if(msg.pid == pid)
+            return 1;
+    }
+    return 1;
+
+}
+
+void
+killzombies(void)
+{
+    Thread *job;
+    int index, status, pid;
+
+    while((pid=waitpid(-1, &status, WNOHANG))>0){
+        print(shell.err, "found zombie pid %d\n", pid);
+        flush(shell.err);
+
+        job = getjob(pid, &index);
+        if(!job)
+            perror("invalid pid");
+
+        if(WIFEXITED(status))
+            job->wait.status = Pdone;
+        if(WIFSTOPPED(status))
+            job->wait.status = Pstop;
+        if(WIFCONTINUED(status))
+            job->wait.status = Pagain;
+
+        if(job->wait.status == Pdone){
+            report(job,index);
+            deljob(job);
+        }
+    }
+}
-- 
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