From 74abc79434fe895d0ca863e4d1d6c5c16b54f296 Mon Sep 17 00:00:00 2001
From: Niklas Halle <niklas@niklashalle.net>
Date: Mon, 1 Jun 2020 15:46:28 +0200
Subject: trying to connect server and shell, weird

---
 03_exercise/srv/builtins.c | 120 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 03_exercise/srv/builtins.c

(limited to '03_exercise/srv/builtins.c')

diff --git a/03_exercise/srv/builtins.c b/03_exercise/srv/builtins.c
new file mode 100644
index 0000000..f5497a3
--- /dev/null
+++ b/03_exercise/srv/builtins.c
@@ -0,0 +1,120 @@
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <wait.h>
+#include <stdlib.h>
+
+
+#include "array.h"
+#include "builtins.h"
+
+void handle(int sig) {
+    /* Do nothing. */
+}
+
+typedef struct {
+    pid_t pid;
+    bool done;
+} hack_struct;
+
+void builtin_wait(process p, bool bind) {
+    struct sigaction handler;
+    handler.sa_handler = handle;
+    sigemptyset(&handler.sa_mask);
+    handler.sa_flags = 0;
+
+    hack_struct *pcs;
+    arrayInit(pcs);
+
+    size_t i = 1;
+    bool             error = false;
+    while (!error && p.argv[i] != NULL) {
+        char        *end;
+        hack_struct pc;
+        pc.pid  = strtol(p.argv[i], &end, 10);
+        pc.done = false;
+        if (*end != '\0') {
+            fprintf(stderr, "Not a valid pid: %s\n", p.argv[i]);
+            error = true;
+            break;
+        }
+        arrayPush(pcs) = pc;
+        ++i;
+    }
+
+    if (error || arrayLen(pcs) == 0) {
+        printf("plz giv pid\n");
+        arrayRelease(pcs);
+        return;
+    }
+
+    int options = WUNTRACED;
+    if (!bind) {
+        options |= WNOHANG;
+    }
+
+    int done_count = 0;
+    while (done_count != arrayLen(pcs)) {
+        for (int j = 0; j < arrayLen(pcs); ++j) {
+            int         status;
+            hack_struct *current_pc = &j[pcs];
+            if (current_pc->done) {
+                continue;
+            }
+
+            if (bind) {
+                printf("Resuming %ld...\n", (long) current_pc->pid);
+            }/* else {
+                printf("Waiting for %ld...\n", (long) current_pc->pid);
+            }*/
+            // install signal handler without SA_RESTART, so waitpid gets interrupted
+            sigaction(SIGINT, &handler, NULL);
+            pid_t res;
+            if ((res = waitpid(current_pc->pid, &status, options)) < 0) {
+                if (EINTR == errno) {
+                    // cancelled by ctrl-c
+                    if (bind) {
+                        current_pc->done = true;
+                        ++done_count;
+                        kill(current_pc->pid, SIGKILL);
+                        waitpid(current_pc->pid, &status, options);
+                        printf("Killed [%ld]\n", (long) current_pc->pid);
+                    } else {
+                        kill(current_pc->pid, SIGCONT);
+                    }
+                } else {
+                    perror("Could not wait for process");
+                    ++done_count;
+                    current_pc->done = true;
+                }
+            } else if (res == 0) {
+                // wait terminated because nohang
+            } else {
+                current_pc->done = true;
+                ++done_count;
+                if (bind) {
+                    printf("[%i] ", WEXITSTATUS(status));
+                } else {
+                    printf("[%i] TERMINATED\n", current_pc->pid);
+                    if (WIFEXITED(status)) {
+                        printf("[%i] exited normally with status: %i\n", current_pc->pid,
+                               WEXITSTATUS(status));
+                    } else if (WIFSTOPPED(status)) {
+                        printf("[%i] was stopped by signal: %s\n", current_pc->pid,
+                               strsignal(WSTOPSIG(status)));
+                    } else if (WIFSIGNALED(status)) {
+                        printf("[%i] was terminated by signal: %s\n", current_pc->pid,
+                               strsignal(WTERMSIG(status)));
+                    } else {
+                        printf("[%i] exited (not sure why), exit status: %i\n", current_pc->pid,
+                               WEXITSTATUS(status));
+                    }
+                }
+            }
+            signal(SIGINT, SIG_IGN);
+        }
+    }
+
+    arrayRelease(pcs);
+}
-- 
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