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scriptd: Wait to notify s6 until script completes.

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The motivation here is to be safe in cases where the script
is setting up firewall rules or tunnels and where subsequent
tasks require these to be complete before starting.

I expect that this is a common case where a script is used.

The implementation behaves almost identically to how ifchd works.
This commit is contained in:
Nicholas J. Kain 2022-09-07 04:45:30 -04:00
parent 4d739acbdd
commit ebd2c4c01a
No known key found for this signature in database
1 changed files with 33 additions and 14 deletions
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47
scriptd.c
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@ -21,22 +21,27 @@ extern char **environ;
bool valid_script_file = false;
// Runs the 'script_file'-specified script. Called from ndhc process.
// Blocks until the script finishes running.
void request_scriptd_run(void)
{
if (!valid_script_file) return;
static char buf[] = "\n";
ssize_t r = safe_write(scriptdSock[0], buf, 1);
char nl = '\n';
ssize_t r = safe_write(scriptdSock[0], &nl, 1);
if (r < 0 || (size_t)r != 1)
suicide("%s: (%s) write failed: %zd", client_config.interface,
__func__, r);
}
static void run_script(void)
{
pid_t pid;
int ret = nk_pspawn(&pid, script_file, NULL, NULL, NULL, environ);
if (ret) log_line("posix_spawn failed for '%s': %s\n", script_file, strerror(ret));
char buf[16];
r = safe_recv(scriptdSock[0], buf, sizeof buf, 0);
if (r == 0) {
// Remote end hung up.
exit(EXIT_SUCCESS);
} else if (r < 0) {
suicide("%s: (%s) recvmsg failed: %s", client_config.interface,
__func__, strerror(errno));
}
if (r != 1 || buf[0] != '+')
suicide("%s: Bad response from recv", __func__);
}
static void process_client_socket(void)
@ -63,7 +68,23 @@ static void process_client_socket(void)
if (buflen > 1 || buf[0] != '\n') exit(EXIT_SUCCESS);
buflen = 0;
run_script();
pid_t pid;
int ret = nk_pspawn(&pid, script_file, NULL, NULL, NULL, environ);
if (ret) log_line("posix_spawn failed for '%s': %s\n", script_file, strerror(ret));
int wstatus;
ret = waitpid(pid, &wstatus, 0);
if (ret == -1)
suicide("%s: (%s) waitpid failed: %s", client_config.interface,
__func__, strerror(errno));
char c = '+';
ssize_t rs = safe_write(scriptdSock[1], &c, 1);
if (rs == 0) {
// Remote end hung up.
exit(EXIT_SUCCESS);
} else if (rs < 0)
suicide("%s: (%s) error writing to scriptd -> ndhc socket: %s",
client_config.interface, __func__, strerror(errno));
}
static void do_scriptd_work(void)
@ -93,9 +114,7 @@ static void do_scriptd_work(void)
static void signal_handler(int signo)
{
int serrno = errno;
if (signo == SIGCHLD) {
while (waitpid(-1, NULL, WNOHANG) > 0);
} else if (signo == SIGINT || signo == SIGTERM) {
if (signo == SIGINT || signo == SIGTERM) {
_exit(EXIT_FAILURE);
}
errno = serrno;
@ -104,7 +123,7 @@ static void signal_handler(int signo)
static void setup_signals_scriptd(void)
{
static const int ss[] = {
SIGCHLD, SIGINT, SIGTERM, SIGKILL
SIGINT, SIGTERM, SIGKILL
};
sigset_t mask;
if (sigprocmask(0, 0, &mask) < 0)