From 9655cd3c95e5374f41617b8e998c7265ecba1a3c Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Tue, 20 Feb 2024 15:41:16 +0100 Subject: [PATCH] bsod: add new option --tty= to specify TTY to output on If specified we'll not try to find a free V, but instead just output directly to the specified TTY. This is particularly useful for debugging, as it means "systemd-bsod --tty=/dev/tty" just works. --- man/systemd-bsod.service.xml | 11 +++++++ src/journal/bsod.c | 60 ++++++++++++++++++++++++------------ 2 files changed, 51 insertions(+), 20 deletions(-) diff --git a/man/systemd-bsod.service.xml b/man/systemd-bsod.service.xml index 9b0a9f4e484..1726b7b5d05 100644 --- a/man/systemd-bsod.service.xml +++ b/man/systemd-bsod.service.xml @@ -55,6 +55,17 @@ + + + + + Specify the TTY to output to. By default systemd-bsod will + automatically find a free VT to display the message on. If this option is specified a TTY may be + selected explicitly. Use to direct output to the terminal the command + is invoked on. + + + diff --git a/src/journal/bsod.c b/src/journal/bsod.c index 688ebdb3510..65107981c8d 100644 --- a/src/journal/bsod.c +++ b/src/journal/bsod.c @@ -17,6 +17,7 @@ #include "log.h" #include "logs-show.h" #include "main-func.h" +#include "parse-argument.h" #include "pretty-print.h" #include "qrcode-util.h" #include "sigbus.h" @@ -25,6 +26,9 @@ #include "terminal-util.h" static bool arg_continuous = false; +static char *arg_tty = NULL; + +STATIC_DESTRUCTOR_REGISTER(arg_tty, freep); static int help(void) { _cleanup_free_ char *link = NULL; @@ -42,6 +46,7 @@ static int help(void) { " --version Show package version\n" " -c --continuous Make systemd-bsod wait continuously\n" " for changes in the journal\n" + " --tty=TTY Specify path to TTY to use\n" "\nSee the %2$s for details.\n", program_invocation_short_name, link, @@ -135,9 +140,9 @@ static int find_next_free_vt(int fd, int *ret_free_vt, int *ret_original_vt) { } static int display_emergency_message_fullscreen(const char *message) { - int r, ret = 0, free_vt = 0, original_vt = 0; + int r, ret = 0, free_vt = -1, original_vt = 0; unsigned qr_code_start_row = 1, qr_code_start_column = 1; - char tty[STRLEN("/dev/tty") + DECIMAL_STR_MAX(int) + 1]; + char ttybuf[STRLEN("/dev/tty") + DECIMAL_STR_MAX(int) + 1]; _cleanup_close_ int fd = -EBADF; _cleanup_fclose_ FILE *stream = NULL; char read_character_buffer = '\0'; @@ -145,30 +150,36 @@ static int display_emergency_message_fullscreen(const char *message) { .ws_col = 80, .ws_row = 25, }; + const char *tty; assert(message); - fd = open_terminal("/dev/tty1", O_RDWR|O_NOCTTY|O_CLOEXEC); - if (fd < 0) - return log_error_errno(fd, "Failed to open tty1: %m"); + if (arg_tty) + tty = arg_tty; + else { + fd = open_terminal("/dev/tty1", O_RDWR|O_NOCTTY|O_CLOEXEC); + if (fd < 0) + return log_error_errno(fd, "Failed to open /dev/tty1: %m"); - r = find_next_free_vt(fd, &free_vt, &original_vt); - if (r < 0) - return log_error_errno(r, "Failed to find a free VT: %m"); + r = find_next_free_vt(fd, &free_vt, &original_vt); + if (r < 0) + return log_error_errno(r, "Failed to find a free VT: %m"); - xsprintf(tty, "/dev/tty%d", free_vt + 1); + xsprintf(ttybuf, "/dev/tty%d", free_vt + 1); + tty = ttybuf; - r = open_terminal(tty, O_RDWR|O_NOCTTY|O_CLOEXEC); - if (r < 0) - return log_error_errno(fd, "Failed to open tty: %m"); + fd = safe_close(fd); + } - close_and_replace(fd, r); + fd = open_terminal(tty, O_RDWR|O_NOCTTY|O_CLOEXEC); + if (fd < 0) + return log_error_errno(fd, "Failed to open %s: %m", tty); if (ioctl(fd, TIOCGWINSZ, &w) < 0) log_warning_errno(errno, "Failed to fetch tty size, ignoring: %m"); - if (ioctl(fd, VT_ACTIVATE, free_vt + 1) < 0) - return log_error_errno(errno, "Failed to activate tty: %m"); + if (free_vt >= 0 && ioctl(fd, VT_ACTIVATE, free_vt + 1) < 0) + return log_error_errno(errno, "Failed to activate tty, ignoring: %m"); r = loop_write(fd, ANSI_BACKGROUND_BLUE ANSI_HOME_CLEAR, SIZE_MAX); if (r < 0) @@ -221,7 +232,7 @@ static int display_emergency_message_fullscreen(const char *message) { ret = log_error_errno(r, "Failed to read character: %m"); cleanup: - if (ioctl(fd, VT_ACTIVATE, original_vt) < 0) + if (original_vt > 0 && ioctl(fd, VT_ACTIVATE, original_vt) < 0) return log_error_errno(errno, "Failed to switch back to original VT: %m"); return ret; @@ -231,16 +242,18 @@ static int parse_argv(int argc, char * argv[]) { enum { ARG_VERSION = 0x100, + ARG_TTY, }; static const struct option options[] = { - { "help", no_argument, NULL, 'h' }, - { "version", no_argument, NULL, ARG_VERSION }, - { "continuous", no_argument, NULL, 'c' }, + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, ARG_VERSION }, + { "continuous", no_argument, NULL, 'c' }, + { "tty", required_argument, NULL, ARG_TTY }, {} }; - int c; + int c, r; assert(argc >= 0); assert(argv); @@ -259,6 +272,13 @@ static int parse_argv(int argc, char * argv[]) { arg_continuous = true; break; + case ARG_TTY: + r = parse_path_argument(optarg, /* suppress_root= */ false, &arg_tty); + if (r < 0) + return r; + + break; + case '?': return -EINVAL; -- 2.47.3