[PATCH v3 06/10] run-command: add clean_on_exit_handler

[larsxschneider@gmail.com]

From: Lars Schneider <larsxschneider@gmail.com>

Some commands might need to perform cleanup tasks on exit. Let's give
them an interface for doing this.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
---
 run-command.c | 12 ++++++++----
 run-command.h |  1 +
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/run-command.c b/run-command.c
index 33bc63a..197b534 100644
--- a/run-command.c
+++ b/run-command.c
@@ -21,6 +21,7 @@ void child_process_clear(struct child_process *child)
 
 struct child_to_clean {
 	pid_t pid;
+	void (*clean_on_exit_handler)(pid_t);
 	struct child_to_clean *next;
 };
 static struct child_to_clean *children_to_clean;
@@ -30,6 +31,8 @@ static void cleanup_children(int sig, int in_signal)
 {
 	while (children_to_clean) {
 		struct child_to_clean *p = children_to_clean;
+		if (p->clean_on_exit_handler)
+			p->clean_on_exit_handler(p->pid);
 		children_to_clean = p->next;
 		kill(p->pid, sig);
 		if (!in_signal)
@@ -49,10 +52,11 @@ static void cleanup_children_on_exit(void)
 	cleanup_children(SIGTERM, 0);
 }
 
-static void mark_child_for_cleanup(pid_t pid)
+static void mark_child_for_cleanup(pid_t pid, void (*clean_on_exit_handler)(pid_t))
 {
 	struct child_to_clean *p = xmalloc(sizeof(*p));
 	p->pid = pid;
+	p->clean_on_exit_handler = clean_on_exit_handler;
 	p->next = children_to_clean;
 	children_to_clean = p;
 
@@ -422,7 +426,7 @@ int start_command(struct child_process *cmd)
 	if (cmd->pid < 0)
 		error_errno("cannot fork() for %s", cmd->argv[0]);
 	else if (cmd->clean_on_exit)
-		mark_child_for_cleanup(cmd->pid);
+		mark_child_for_cleanup(cmd->pid, cmd->clean_on_exit_handler);
 
 	/*
 	 * Wait for child's execvp. If the execvp succeeds (or if fork()
@@ -483,7 +487,7 @@ int start_command(struct child_process *cmd)
 	if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 		error_errno("cannot spawn %s", cmd->argv[0]);
 	if (cmd->clean_on_exit && cmd->pid >= 0)
-		mark_child_for_cleanup(cmd->pid);
+		mark_child_for_cleanup(cmd->pid, cmd->clean_on_exit_handler);
 
 	argv_array_clear(&nargv);
 	cmd->argv = sargv;
@@ -752,7 +756,7 @@ int start_async(struct async *async)
 		exit(!!async->proc(proc_in, proc_out, async->data));
 	}
 
-	mark_child_for_cleanup(async->pid);
+	mark_child_for_cleanup(async->pid, NULL);
 
 	if (need_in)
 		close(fdin[0]);
diff --git a/run-command.h b/run-command.h
index 5066649..59d21ea 100644
--- a/run-command.h
+++ b/run-command.h
@@ -43,6 +43,7 @@ struct child_process {
 	unsigned stdout_to_stderr:1;
 	unsigned use_shell:1;
 	unsigned clean_on_exit:1;
+	void (*clean_on_exit_handler)(pid_t);
 };
 
 #define CHILD_PROCESS_INIT { NULL, ARGV_ARRAY_INIT, ARGV_ARRAY_INIT }
-- 
2.9.0