Track pid of child process from exec

This will allow us to eventually open that process on the current view.
Requires support from @Cloudef.

1 files changed, 18 insertions, 3 deletions

diff --git a/sway/commands.c b/sway/commands.c
index dfb3c12d..3181b434 100644
--- a/sway/commands.c
+++ b/sway/commands.c
@@ -214,22 +214,37 @@ static struct cmd_results *cmd_exec_always(int argc, char **argv) {
         free(tmp);
         sway_log(L_DEBUG, "Executing %s", cmd);
 
+        int fd[2];
+        pipe(fd);
+
         pid_t pid;
+        pid_t *child = malloc(sizeof(pid_t)); // malloc'd so that Linux can avoid copying the process space
         // Fork process
         if ((pid = fork()) == 0) {
                 // Fork child process again
                 setsid();
-                if (fork() == 0) {
+                if ((*child = fork()) == 0) {
                         execl("/bin/sh", "/bin/sh", "-c", cmd, (void *)NULL);
                         /* Not reached */
                 }
-                // Close child process
-                _exit(0);
+                close(fd[0]);
+                write(fd[1], child, sizeof(pid_t));
+                close(fd[1]);
+                _exit(0); // Close child process
         } else if (pid < 0) {
                 return cmd_results_new(CMD_FAILURE, "exec_always", "Command failed (sway could not fork).");
         }
+        close(fd[1]); // close write
+        read(fd[0], child, sizeof(pid_t));
+        close(fd[0]);
         // cleanup child process
         wait(0);
+        if (*child > 0) {
+                sway_log(L_DEBUG, "Child process created with pid %d", *child);
+                // TODO: keep track of this pid and open the corresponding view on the current workspace
+                // blocked pending feature in wlc
+        }
+        free(child);
         return cmd_results_new(CMD_SUCCESS, NULL, NULL);
 }