diff --git a/qemu-doc.texi b/qemu-doc.texi index ea4d2e63a4c9f918c412db93497c87c82d2a2df9..6796aeb6d36e986177c89d04fcbc843437c94c65 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -309,6 +309,12 @@ Start in full screen. Store the QEMU process PID in @var{file}. It is useful if you launch QEMU from a script. +@item -daemonize +Daemonize the QEMU process after initialization. QEMU will not detach from +standard IO until it is ready to receive connections on any of its devices. +This option is a useful way for external programs to launch QEMU without having +to cope with initialization race conditions. + @item -win2k-hack Use it when installing Windows 2000 to avoid a disk full bug. After Windows 2000 is installed, you no longer need this option (this option diff --git a/vl.c b/vl.c index 929d2a938c463ad825406cafcf66d354f9e164a3..c56c87cfe6825437828c98e6d3a2bb736c926f78 100644 --- a/vl.c +++ b/vl.c @@ -163,6 +163,7 @@ const char *vnc_display; int acpi_enabled = 1; int fd_bootchk = 1; int no_reboot = 0; +int daemonize = 0; /***********************************************************/ /* x86 ISA bus support */ @@ -6018,6 +6019,9 @@ void help(void) "-no-reboot exit instead of rebooting\n" "-loadvm file start right away with a saved state (loadvm in monitor)\n" "-vnc display start a VNC server on display\n" +#ifndef _WIN32 + "-daemonize daemonize QEMU after initializing\n" +#endif "\n" "During emulation, the following keys are useful:\n" "ctrl-alt-f toggle full screen\n" @@ -6098,6 +6102,7 @@ enum { QEMU_OPTION_vnc, QEMU_OPTION_no_acpi, QEMU_OPTION_no_reboot, + QEMU_OPTION_daemonize, }; typedef struct QEMUOption { @@ -6178,6 +6183,7 @@ const QEMUOption qemu_options[] = { { "cirrusvga", 0, QEMU_OPTION_cirrusvga }, { "no-acpi", 0, QEMU_OPTION_no_acpi }, { "no-reboot", 0, QEMU_OPTION_no_reboot }, + { "daemonize", 0, QEMU_OPTION_daemonize }, { NULL }, }; @@ -6408,6 +6414,7 @@ int main(int argc, char **argv) QEMUMachine *machine; char usb_devices[MAX_USB_CMDLINE][128]; int usb_devices_index; + int fds[2]; LIST_INIT (&vm_change_state_head); #ifndef _WIN32 @@ -6826,10 +6833,61 @@ int main(int argc, char **argv) case QEMU_OPTION_no_reboot: no_reboot = 1; break; + case QEMU_OPTION_daemonize: + daemonize = 1; + break; } } } +#ifndef _WIN32 + if (daemonize && !nographic && vnc_display == NULL) { + fprintf(stderr, "Can only daemonize if using -nographic or -vnc\n"); + daemonize = 0; + } + + 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 || status != 0) + exit(1); + else + exit(0); + } else if (pid < 0) + exit(1); + + setsid(); + + pid = fork(); + if (pid > 0) + exit(0); + else if (pid < 0) + exit(1); + + umask(027); + chdir("/"); + + signal(SIGTSTP, SIG_IGN); + signal(SIGTTOU, SIG_IGN); + signal(SIGTTIN, SIG_IGN); + } +#endif + #ifdef USE_KQEMU if (smp_cpus > 1) kqemu_allowed = 0; @@ -7028,6 +7086,30 @@ int main(int argc, char **argv) } } + if (daemonize) { + uint8_t status = 0; + ssize_t len; + int fd; + + again1: + len = write(fds[1], &status, 1); + if (len == -1 && (errno == EINTR)) + goto again1; + + if (len != 1) + exit(1); + + fd = open("/dev/null", O_RDWR); + if (fd == -1) + exit(1); + + dup2(fd, 0); + dup2(fd, 1); + dup2(fd, 2); + + close(fd); + } + main_loop(); quit_timers(); return 0;