cd776cf96
Peter Korsgaard
2013-01-06
Subject
syslogd: add option to log to Linux kernel printk buffer
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sysklogd/Config.src+16 -0
| @@ -113,6 +113,19 @@ config FEATURE_LOGREAD_REDUCED_LOCKING | |
| from circular buffer, minimizing semaphore | |
| contention at some minor memory expense. | |
| + | config FEATURE_KMSG_SYSLOG |
| + | bool "Linux kernel printk buffer support" |
| + | default y |
| + | depends on SYSLOGD |
| + | select PLATFORM_LINUX |
| + | help |
| + | When you enable this feature, the syslogd utility will |
| + | write system log message to the Linux kernel's printk buffer. |
| + | This can be used as a smaller alternative to the syslogd IPC |
| + | support, as klogd and logread aren't needed. |
| + | |
| + | NOTICE: Syslog facilities in log entries needs kernel 3.5+. |
| + | |
| config KLOGD | |
| bool "klogd" | |
| default y | |
| @@ -123,6 +136,9 @@ config KLOGD | |
| you wish to record the messages produced by the kernel, | |
| you should enable this option. | |
| + | comment "klogd should not be used together with syslog to kernel printk buffer" |
| + | depends on KLOGD && FEATURE_KMSG_SYSLOG |
| + | |
| config FEATURE_KLOGD_KLOGCTL | |
| bool "Use the klogctl() interface" | |
| default y | |
sysklogd/syslogd.c+60 -1
| @@ -43,6 +43,9 @@ | |
| //usage: "\n -f FILE Use FILE as config (default:/etc/syslog.conf)" | |
| //usage: ) | |
| /* //usage: "\n -m MIN Minutes between MARK lines (default:20, 0=off)" */ | |
| + | //usage: IF_FEATURE_KMSG_SYSLOG( |
| + | //usage: "\n -K Log to kernel printk buffer (use dmesg to read it)" |
| + | //usage: ) |
| //usage: | |
| //usage:#define syslogd_example_usage | |
| //usage: "$ syslogd -R masterlog:514\n" | |
| @@ -140,6 +143,10 @@ IF_FEATURE_IPC_SYSLOG( \ | |
| ) \ | |
| IF_FEATURE_SYSLOGD_CFG( \ | |
| logRule_t *log_rules; \ | |
| + | ) \ |
| + | IF_FEATURE_KMSG_SYSLOG( \ |
| + | int kmsgfd; \ |
| + | int primask; \ |
| ) | |
| struct init_globals { | |
| @@ -212,6 +219,7 @@ enum { | |
| IF_FEATURE_IPC_SYSLOG( OPTBIT_circularlog,) // -C | |
| IF_FEATURE_SYSLOGD_DUP( OPTBIT_dup ,) // -D | |
| IF_FEATURE_SYSLOGD_CFG( OPTBIT_cfg ,) // -f | |
| + | IF_FEATURE_KMSG_SYSLOG( OPTBIT_kmsg ,) // -K |
| OPT_mark = 1 << OPTBIT_mark , | |
| OPT_nofork = 1 << OPTBIT_nofork , | |
| @@ -225,6 +233,8 @@ enum { | |
| OPT_circularlog = IF_FEATURE_IPC_SYSLOG( (1 << OPTBIT_circularlog)) + 0, | |
| OPT_dup = IF_FEATURE_SYSLOGD_DUP( (1 << OPTBIT_dup )) + 0, | |
| OPT_cfg = IF_FEATURE_SYSLOGD_CFG( (1 << OPTBIT_cfg )) + 0, | |
| + | OPT_kmsg = IF_FEATURE_KMSG_SYSLOG( (1 << OPTBIT_kmsg )) + 0, |
| + | |
| }; | |
| #define OPTION_STR "m:nO:l:S" \ | |
| IF_FEATURE_ROTATE_LOGFILE("s:" ) \ | |
| @@ -233,7 +243,8 @@ enum { | |
| IF_FEATURE_REMOTE_LOG( "L" ) \ | |
| IF_FEATURE_IPC_SYSLOG( "C::") \ | |
| IF_FEATURE_SYSLOGD_DUP( "D" ) \ | |
| - | IF_FEATURE_SYSLOGD_CFG( "f:" ) |
| + | IF_FEATURE_SYSLOGD_CFG( "f:" ) \ |
| + | IF_FEATURE_KMSG_SYSLOG( "K" ) |
| #define OPTION_DECL *opt_m, *opt_l \ | |
| IF_FEATURE_ROTATE_LOGFILE(,*opt_s) \ | |
| IF_FEATURE_ROTATE_LOGFILE(,*opt_b) \ | |
| @@ -523,6 +534,44 @@ void ipcsyslog_init(void); | |
| void log_to_shmem(const char *msg); | |
| #endif /* FEATURE_IPC_SYSLOG */ | |
| + | #if ENABLE_FEATURE_KMSG_SYSLOG |
| + | static void kmsg_init(void) |
| + | { |
| + | G.kmsgfd = xopen("/dev/kmsg", O_WRONLY); |
| + | |
| + | /* |
| + | * kernel < 3.5 expects single char printk KERN_* priority prefix, |
| + | * from 3.5 onwards the full syslog facility/priority format is supported |
| + | */ |
| + | if (get_linux_version_code() < KERNEL_VERSION(3,5,0)) |
| + | G.primask = LOG_PRIMASK; |
| + | else |
| + | G.primask = -1; |
| + | } |
| + | |
| + | static void kmsg_cleanup(void) |
| + | { |
| + | if (ENABLE_FEATURE_CLEAN_UP) |
| + | close(G.kmsgfd); |
| + | } |
| + | |
| + | /* Write message to /dev/kmsg */ |
| + | static void log_to_kmsg(int pri, const char *msg) |
| + | { |
| + | /* |
| + | * kernel < 3.5 expects single char printk KERN_* priority prefix, |
| + | * from 3.5 onwards the full syslog facility/priority format is supported |
| + | */ |
| + | pri &= G.primask; |
| + | |
| + | write(G.kmsgfd, G.printbuf, sprintf(G.printbuf, "<%d>%s\n", pri, msg)); |
| + | } |
| + | #else |
| + | void kmsg_init(void); |
| + | void kmsg_cleanup(void); |
| + | void log_to_kmsg(int pri, const char *msg); |
| + | #endif /* FEATURE_KMSG_SYSLOG */ |
| + | |
| /* Print a message to the log file. */ | |
| static void log_locally(time_t now, char *msg, logFile_t *log_file) | |
| { | |
| @@ -657,6 +706,11 @@ static void timestamp_and_log(int pri, char *msg, int len) | |
| } | |
| timestamp[15] = '\0'; | |
| + | if (ENABLE_FEATURE_KMSG_SYSLOG && (option_mask32 & OPT_kmsg)) { |
| + | log_to_kmsg(pri, msg); |
| + | return; |
| + | } |
| + | |
| if (option_mask32 & OPT_small) | |
| sprintf(G.printbuf, "%s %s\n", timestamp, msg); | |
| else { | |
| @@ -831,6 +885,9 @@ static void do_syslogd(void) | |
| ipcsyslog_init(); | |
| } | |
| + | if (ENABLE_FEATURE_KMSG_SYSLOG && (option_mask32 & OPT_kmsg)) |
| + | kmsg_init(); |
| + | |
| timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER); | |
| while (!bb_got_signal) { | |
| @@ -919,6 +976,8 @@ static void do_syslogd(void) | |
| remove_pidfile(CONFIG_PID_FILE_PATH "/syslogd.pid"); | |
| if (ENABLE_FEATURE_IPC_SYSLOG) | |
| ipcsyslog_cleanup(); | |
| + | if (ENABLE_FEATURE_KMSG_SYSLOG && (option_mask32 & OPT_kmsg)) |
| + | kmsg_cleanup(); |
| kill_myself_with_sig(bb_got_signal); | |
| #undef recvbuf | |
| } | |