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Fix 'start' command bug when invoked via JNI

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Child process was using return not exit(), which was unrolling the
JNI call stack in a sub-process and causing havoc.
This commit is contained in:
Andrew Bettison 2012-05-08 16:33:51 +09:30
parent 8aae21232f
commit da9fe6fdca
1 changed files with 49 additions and 48 deletions
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97
commandline.c
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@ -565,11 +565,8 @@ int app_server_start(int argc, const char *const *argv, struct command_line_opti
if (pid > 0) {
WHYF("Serval process already running (pid=%d)", pid);
} else {
/* Start the Serval process.
All server settings will be read by the server process from the
instance directory when it starts up.
We can just become the server process ourselves --- no need to fork.
*/
/* Start the Serval process. All server settings will be read by the server process from the
instance directory when it starts up. */
if (server_remove_stopfile() == -1)
return -1;
rhizome_datastore_path = serval_instancepath();
@ -577,48 +574,53 @@ int app_server_start(int argc, const char *const *argv, struct command_line_opti
overlayMode = 1;
if (foregroundP)
return server(NULL);
switch ((pid = fork())) {
int cpid;
switch ((cpid = fork())) {
case -1:
return WHYF("fork() failed: %s [errno=%d]", strerror(errno), errno);
case 0: { // Child process.
chdir("/");
close(0);
open("/dev/null", O_RDONLY);
close(1);
open("/dev/null", O_WRONLY);
close(2);
open("/dev/null", O_WRONLY);
/* The execpath option is provided so that a JNI call to "start" can be made which creates a
new server daemon process with the correct argv[0]. Otherwise, the servald process appears
as a process with argv[0] = "org.servalproject". */
if (execpath) {
execl(execpath, execpath, "start", "foreground", NULL);
return -1;
return WHY_perror("fork");
case 0: {
/* Child process. Fork then exit, to disconnect daemon from parent process, so that
when daemon exits it does not live on as a zombie. N.B. Do not return from within this
process; that will unroll the JNI call stack and cause havoc. Use exit(). */
switch (fork()) {
case -1:
exit(WHY_perror("fork"));
case 0: { // Grandchild process
chdir("/");
close(0);
open("/dev/null", O_RDONLY);
close(1);
open("/dev/null", O_WRONLY);
close(2);
open("/dev/null", O_WRONLY);
/* The execpath option is provided so that a JNI call to "start" can be made which
creates a new server daemon process with the correct argv[0]. Otherwise, the servald
process appears as a process with argv[0] = "org.servalproject". */
if (execpath) {
execl(execpath, execpath, "start", "foreground", NULL);
exit(-1);
}
exit(server(NULL));
}
}
return server(NULL);
}
default: { // Parent process
/* Allow a few seconds for the process to start. */
int rpid = 0;
time_t timeout = overlay_gettime_ms() + 5000;
do {
struct timespec delay;
delay.tv_sec = 0;
delay.tv_nsec = 200000000; // 200 ms = 5 Hz
nanosleep(&delay, NULL);
} while ((rpid = server_pid()) == 0 && overlay_gettime_ms() < timeout);
if (rpid == -1)
return -1;
if (rpid == 0)
return WHY("Server process did not start");
if (rpid != pid) {
WHYF("Started server process has pid=%d, expecting pid=%d", rpid, pid);
pid = rpid;
}
ret = 0;
break;
exit(0); // Parent is waitpid()-ing for this.
}
}
/* Parent process. Wait for the child process to fork the grandchild then die. */
waitpid(cpid, NULL, 0);
/* Allow a few seconds for the grandchild process to report for duty. */
time_t timeout = overlay_gettime_ms() + 5000;
do {
struct timespec delay;
delay.tv_sec = 0;
delay.tv_nsec = 200000000; // 200 ms = 5 Hz
nanosleep(&delay, NULL);
} while ((pid = server_pid()) == 0 && overlay_gettime_ms() < timeout);
if (pid == -1)
return -1;
if (pid == 0)
return WHY("Server process did not start");
ret = 0;
}
cli_puts("instancepath");
cli_delim(":");
@ -654,8 +656,8 @@ int app_server_stop(int argc, const char *const *argv, struct command_line_optio
while (running == pid) {
if (tries >= 5)
return WHYF(
"Serval process for instance '%s' did not stop after %d SIGHUP signals",
instancepath, tries
"Servald pid=%d for instance '%s' did not stop after %d SIGHUP signals",
pid, instancepath, tries
);
++tries;
/* Create the stopfile, which causes the server process's signal handler to exit
@ -668,9 +670,8 @@ int app_server_stop(int argc, const char *const *argv, struct command_line_optio
serverCleanUp();
break;
}
return WHYF("Error sending SIGHUP to Serval instance '%s' process pid=%d: %s [errno=%d]",
instancepath, pid, strerror(errno), errno
);
WHY_perror("kill");
return WHYF("Error sending SIGHUP to Servald pid=%d for instance '%s'", pid, instancepath);
}
/* Allow a few seconds for the process to die. */
time_t timeout = overlay_gettime_ms() + 2000;