From ab51b1d568e02c80b1abf9016bda3a86dc1db389 Mon Sep 17 00:00:00 2001 From: Michael Tokarev Date: Sun, 30 Dec 2012 12:48:14 +0400 Subject: [PATCH] disallow -daemonize usage of stdio (curses display, -nographic, -serial stdio etc) Curses display requires stdin/out to stay on the terminal, so -daemonize makes no sense in this case. Instead of leaving display uninitialized like is done since 995ee2bf469de6bb, explicitly detect this case earlier and error out. -nographic can actually be used with -daemonize, by redirecting everything to a null device, but the problem is that according to documentation and historical behavour, -nographic redirects guest ports to stdin/out, which, again, makes no sense in case of -daemonize. Since -nographic is a legacy option, don't bother fixing this case (to allow -nographic and -daemonize by redirecting guest ports to null instead of stdin/out in this case), but disallow it completely instead, to stop garbling host terminal. If no display display needed and user wants to use -nographic, the right way to go is to use -serial null -parallel null -monitor none -display none -vga none instead of -nographic. Also prevent the same issue -- it was possible to get garbled host tty after -nographic -daemonize and it is still possible to have it by using -serial stdio -daemonize Fix this by disallowing opening stdio chardev when -daemonize is specified. Signed-off-by: Michael Tokarev Signed-off-by: Anthony Liguori --- qemu-char.c | 4 ++++ vl.c | 28 +++++++++++++++++++++++++--- 2 files changed, 29 insertions(+), 3 deletions(-) diff --git a/qemu-char.c b/qemu-char.c index c6382a93f5..331ad5c087 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -772,6 +772,10 @@ static CharDriverState *qemu_chr_open_stdio(QemuOpts *opts) if (stdio_nb_clients >= STDIO_MAX_CLIENTS) { return NULL; } + if (is_daemonized()) { + error_report("cannot use stdio with -daemonize"); + return NULL; + } if (stdio_nb_clients == 0) { old_fd0_flags = fcntl(0, F_GETFL); tcgetattr (0, &oldtty); diff --git a/vl.c b/vl.c index e6a8d89acc..f056c95807 100644 --- a/vl.c +++ b/vl.c @@ -3637,6 +3637,30 @@ int main(int argc, char **argv, char **envp) default_sdcard = 0; } + if (is_daemonized()) { + /* According to documentation and historically, -nographic redirects + * serial port, parallel port and monitor to stdio, which does not work + * with -daemonize. We can redirect these to null instead, but since + * -nographic is legacy, let's just error out. + * We disallow -nographic only if all other ports are not redirected + * explicitly, to not break existing legacy setups which uses + * -nographic _and_ redirects all ports explicitly - this is valid + * usage, -nographic is just a no-op in this case. + */ + if (display_type == DT_NOGRAPHIC + && (default_parallel || default_serial + || default_monitor || default_virtcon)) { + fprintf(stderr, "-nographic can not be used with -daemonize\n"); + exit(1); + } +#ifdef CONFIG_CURSES + if (display_type == DT_CURSES) { + fprintf(stderr, "curses display can not be used with -daemonize\n"); + exit(1); + } +#endif + } + if (display_type == DT_NOGRAPHIC) { if (default_parallel) add_device_config(DEV_PARALLEL, "null"); @@ -3903,9 +3927,7 @@ int main(int argc, char **argv, char **envp) break; #if defined(CONFIG_CURSES) case DT_CURSES: - if (!is_daemonized()) { - curses_display_init(ds, full_screen); - } + curses_display_init(ds, full_screen); break; #endif #if defined(CONFIG_SDL) -- 2.11.0