Merge branch 'jk/execv-dashed-external' into maint

Typing ^C to pager, which usually does not kill it, killed Git and
took the pager down as a collateral damage in certain process-tree
structure.  This has been fixed.

* jk/execv-dashed-external:
  execv_dashed_external: wait for child on signal death
  execv_dashed_external: stop exiting with negative code
  execv_dashed_external: use child_process struct

Author: gitster

git.c

@@ -575,8 +575,7 @@ static void handle_builtin(int argc, const char **argv)
 
 static void execv_dashed_external(const char **argv)
 {
-	struct strbuf cmd = STRBUF_INIT;
-	const char *tmp;
+	struct child_process cmd = CHILD_PROCESS_INIT;
 	int status;
 
 	if (get_super_prefix())
@@ -586,30 +585,25 @@ static void execv_dashed_external(const char **argv)
 		use_pager = check_pager_config(argv[0]);
 	commit_pager_choice();
 
-	strbuf_addf(&cmd, "git-%s", argv[0]);
+	argv_array_pushf(&cmd.args, "git-%s", argv[0]);
+	argv_array_pushv(&cmd.args, argv + 1);
+	cmd.clean_on_exit = 1;
+	cmd.wait_after_clean = 1;
+	cmd.silent_exec_failure = 1;
 
-	/*
-	 * argv[0] must be the git command, but the argv array
-	 * belongs to the caller, and may be reused in
-	 * subsequent loop iterations. Save argv[0] and
-	 * restore it on error.
-	 */
-	tmp = argv[0];
-	argv[0] = cmd.buf;
-
-	trace_argv_printf(argv, "trace: exec:");
+	trace_argv_printf(cmd.args.argv, "trace: exec:");
 
 	/*
-	 * if we fail because the command is not found, it is
-	 * OK to return. Otherwise, we just pass along the status code.
+	 * If we fail because the command is not found, it is
+	 * OK to return. Otherwise, we just pass along the status code,
+	 * or our usual generic code if we were not even able to exec
+	 * the program.
 	 */
-	status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
-	if (status >= 0 || errno != ENOENT)
+	status = run_command(&cmd);
+	if (status >= 0)
 		exit(status);
-
-	argv[0] = tmp;
-
-	strbuf_release(&cmd);
+	else if (errno != ENOENT)
+		exit(128);
 }
 
 static int run_argv(int *argcp, const char ***argv)

run-command.c

@@ -29,6 +29,8 @@ static int installed_child_cleanup_handler;
 
 static void cleanup_children(int sig, int in_signal)
 {
+	struct child_to_clean *children_to_wait_for = NULL;
+
 	while (children_to_clean) {
 		struct child_to_clean *p = children_to_clean;
 		children_to_clean = p->next;
@@ -45,6 +47,23 @@ static void cleanup_children(int sig, int in_signal)
 		}
 
 		kill(p->pid, sig);
+
+		if (p->process->wait_after_clean) {
+			p->next = children_to_wait_for;
+			children_to_wait_for = p;
+		} else {
+			if (!in_signal)
+				free(p);
+		}
+	}
+
+	while (children_to_wait_for) {
+		struct child_to_clean *p = children_to_wait_for;
+		children_to_wait_for = p->next;
+
+		while (waitpid(p->pid, NULL, 0) < 0 && errno == EINTR)
+			; /* spin waiting for process exit or error */
+
 		if (!in_signal)
 			free(p);
 	}

run-command.h

@@ -43,6 +43,7 @@ struct child_process {
 	unsigned stdout_to_stderr:1;
 	unsigned use_shell:1;
 	unsigned clean_on_exit:1;
+	unsigned wait_after_clean:1;
 	void (*clean_on_exit_handler)(struct child_process *process);
 	void *clean_on_exit_handler_cbdata;
 };