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-rw-r--r--os-posix.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/os-posix.c b/os-posix.c
index 6417d16dca..1672e06550 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -39,6 +39,8 @@
static struct passwd *user_pwd;
static const char *chroot_dir;
+static int daemonize;
+static int fds[2];
void os_setup_early_signal_handling(void)
{
@@ -160,6 +162,9 @@ void os_parse_cmd_args(int index, const char *optarg)
case QEMU_OPTION_chroot:
chroot_dir = optarg;
break;
+ case QEMU_OPTION_daemonize:
+ daemonize = 1;
+ break;
}
return;
}
@@ -196,3 +201,100 @@ void os_change_root(void)
}
}
+
+void os_daemonize(void)
+{
+ if (daemonize) {
+ pid_t pid;
+
+ if (pipe(fds) == -1)
+ exit(1);
+
+ pid = fork();
+ if (pid > 0) {
+ uint8_t status;
+ ssize_t len;
+
+ close(fds[1]);
+
+ again:
+ len = read(fds[0], &status, 1);
+ if (len == -1 && (errno == EINTR))
+ goto again;
+
+ if (len != 1)
+ exit(1);
+ else if (status == 1) {
+ fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno));
+ exit(1);
+ } else
+ exit(0);
+ } else if (pid < 0)
+ exit(1);
+
+ close(fds[0]);
+ qemu_set_cloexec(fds[1]);
+
+ setsid();
+
+ pid = fork();
+ if (pid > 0)
+ exit(0);
+ else if (pid < 0)
+ exit(1);
+
+ umask(027);
+
+ signal(SIGTSTP, SIG_IGN);
+ signal(SIGTTOU, SIG_IGN);
+ signal(SIGTTIN, SIG_IGN);
+ }
+}
+
+void os_setup_post(void)
+{
+ int fd = 0;
+
+ if (daemonize) {
+ uint8_t status = 0;
+ ssize_t len;
+
+ again1:
+ len = write(fds[1], &status, 1);
+ if (len == -1 && (errno == EINTR))
+ goto again1;
+
+ if (len != 1)
+ exit(1);
+
+ if (chdir("/")) {
+ perror("not able to chdir to /");
+ exit(1);
+ }
+ TFR(fd = qemu_open("/dev/null", O_RDWR));
+ if (fd == -1)
+ exit(1);
+ }
+
+ os_change_root();
+ os_change_process_uid();
+
+ if (daemonize) {
+ dup2(fd, 0);
+ dup2(fd, 1);
+ dup2(fd, 2);
+
+ close(fd);
+ }
+}
+
+void os_pidfile_error(void)
+{
+ if (daemonize) {
+ uint8_t status = 1;
+ if (write(fds[1], &status, 1) != 1) {
+ perror("daemonize. Writing to pipe\n");
+ }
+ } else
+ fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno));
+}