Fix SIGINT handling, don't use lsof

koordinates · Jun 16, 2023 · 804946f · 804946f
1 parent ef749f2
commit 804946f
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Showing 2 changed files with 17 additions and 19 deletions.
diff --git a/cli_helper/kart.c b/cli_helper/kart.c
@@ -194,7 +194,7 @@ int is_helper_enabled()
 /**
  * @brief Exit signal handler for SIGALRM
  */
-void exit_on_sigalrm(int sig)
+void exit_on_alarm(int sig)
 {
     int semval = semctl(semid, SEMNUM, GETVAL);
     if (semval < 0)
@@ -209,21 +209,6 @@ void exit_on_sigalrm(int sig)
     exit(exit_code);
 }
 
-char *socket_filename;
-
-/**
- * @brief Exit signal handler for SIGINT
- */
-void exit_on_sigint(int sig)
-{
-    putchar('\n');
-    const char* kill_cmd_template = "lsof -t '%s' | xargs kill";
-    char* kill_cmd = malloc(strlen(kill_cmd_template) + strlen(socket_filename) + 2);
-    sprintf(kill_cmd, kill_cmd_template, socket_filename);
-    system(kill_cmd);
-    exit(128 + sig);
-}
-
 int main(int argc, char **argv, char **environ)
 {
     char cmd_path[PATH_MAX];
@@ -236,6 +221,10 @@ int main(int argc, char **argv, char **environ)
     {
         debug("enabled %s, pid=%d\n", cmd_path, getpid());
 
+        // Make this process the leader of a process group:
+        // The procress-group ID (pgid) will be the same as the pid.
+        setpgrp();
+
         // start or use an existing helper process
         char **env_ptr;
 
@@ -282,7 +271,7 @@ int main(int argc, char **argv, char **environ)
         int fp = open(getcwd(NULL, 0), O_RDONLY);
         int fds[4] = {fileno(stdin), fileno(stdout), fileno(stderr), fp};
 
-        socket_filename = malloc(strlen(getenv("HOME")) + strlen(".kart.socket") + 2);
+        char *socket_filename = malloc(strlen(getenv("HOME")) + strlen(".kart.socket") + 2);
         sprintf(socket_filename, "%s/%s", getenv("HOME"), ".kart.socket");
         int socket_fd = socket(AF_UNIX, SOCK_STREAM, 0);
 
@@ -385,8 +374,7 @@ int main(int argc, char **argv, char **environ)
         memcpy((int *)CMSG_DATA(cmsg), fds, sizeof(fds));
         msg.msg_controllen = cmsg->cmsg_len;
 
-        signal(SIGALRM, exit_on_sigalrm);
-        signal(SIGINT, exit_on_sigint);
+        signal(SIGALRM, exit_on_alarm);
 
         if (sendmsg(socket_fd, &msg, 0) < 0)
         {

diff --git a/kart/helper.py b/kart/helper.py
@@ -133,6 +133,7 @@ def helper(ctx, socket_filename, timeout, args):
             else:
                 # child
                 _helper_log("post-fork")
+
                 payload, fds = recv_json_and_fds(client, maxfds=4)
                 if not payload or len(fds) != 4:
                     click.echo(
@@ -169,6 +170,15 @@ def helper(ctx, socket_filename, timeout, args):
                         f"Payload:\n{repr(payload)}",
                     )
                 else:
+                    try:
+                        # Join the process group of the calling process - so that if they get killed, we get killed to.
+                        os.setpgid(0, calling_environment["pid"])
+                    except Exception as e:
+                        # Kart will still work even if this fails: it just means SIGINT Ctrl+C might not work properly.
+                        # We'll just log it and hope for the best.
+                        _helper_log(f"error joining caller's process group: {e}")
+                        pass
+
                     sys.argv[1:] = calling_environment["argv"][1:]
                     _helper_log(f"cmd={' '.join(calling_environment['argv'])}")
                     os.environ.clear()