From e9e41c02d4309cd50b5584a8dfc0d7e01cb27e10 Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Wed, 22 Jul 2020 18:48:30 +0200
Subject: Kill child process when parent dies

---
 src/command.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

(limited to 'src/command.c')

diff --git a/src/command.c b/src/command.c
index c413502..d44c773 100644
--- a/src/command.c
+++ b/src/command.c
@@ -1,10 +1,13 @@
 #include "../include/command.h"
 #include <unistd.h>
 #include <sys/wait.h>
+#include <sys/prctl.h>
+#include <signal.h>
 #include <errno.h>
 #include <string.h>
 #include <stdio.h>
 #include <assert.h>
+#include <stdlib.h>
 
 #define READ_END 0
 #define WRITE_END 1
@@ -12,6 +15,7 @@
 int tsl_command_exec(char **args, ProgramOutputCallback output_callback, void *userdata) {
     int fd[2];
     pid_t pid;
+    pid_t parent_pid = getpid();
 
     /* 1 arguments */
     if(args[0] == NULL)
@@ -25,14 +29,26 @@ int tsl_command_exec(char **args, ProgramOutputCallback output_callback, void *u
     pid = fork();
     if(pid == -1) {
         perror("Failed to fork");
+        close(fd[READ_END]);
+        close(fd[WRITE_END]);
         return -3;
     } else if(pid == 0) { /* child */
+        if(prctl(PR_SET_PDEATHSIG, SIGTERM) == -1) {
+            perror("prctl(PR_SET_PDEATHSIG, SIGTERM) failed");
+            exit(127);
+        }
+
+        /* Test if the parent died before the above call to prctl */
+        if(getppid() != parent_pid)
+            exit(127);
+
         dup2(fd[WRITE_END], STDOUT_FILENO);
         close(fd[READ_END]);
         close(fd[WRITE_END]);
 
         execvp(args[0], args);
-        return 0;
+        perror("execvp");
+        exit(127);
     } else { /* parent */
         int result = 0;
         int status;
@@ -71,7 +87,6 @@ int tsl_command_exec(char **args, ProgramOutputCallback output_callback, void *u
         if(exit_status != 0) {
             char **arg = args;
             fprintf(stderr, "Failed to execute program (");
-            
             while(*arg) {
                 if(arg != args)
                     fputc(' ', stderr);
-- 
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