diff options
| -rw-r--r-- | sys-utils/dmesg.1 | 3 | ||||
| -rw-r--r-- | sys-utils/dmesg.c | 25 |
2 files changed, 23 insertions, 5 deletions
diff --git a/sys-utils/dmesg.1 b/sys-utils/dmesg.1 index 8e6088e49..ff149a9e3 100644 --- a/sys-utils/dmesg.1 +++ b/sys-utils/dmesg.1 @@ -127,6 +127,9 @@ Do not print kernel's timestamps. Print userspace messages. .IP "\fB\-V\fR, \fB\-\-version\fR" Output version information and exit. +.IP "\fB\-w\fR, \fB\-\-follow\fR" +Wait for new messages. This feature is supported on systems with readable +/dev/kmsg only (since kernel 3.5.0). .IP "\fB\-x\fR, \fB\-\-decode\fR" Decode facility and level (priority) number to human readable prefixes. .SH SEE ALSO diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c index 46d1e3106..319fcd5f8 100644 --- a/sys-utils/dmesg.c +++ b/sys-utils/dmesg.c @@ -136,7 +136,8 @@ struct dmesg_control { char *mmap_buff; size_t pagesize; - unsigned int raw:1, /* raw mode */ + unsigned int follow:1, /* wait for new messages */ + raw:1, /* raw mode */ fltr_lev:1, /* filter out by levels[] */ fltr_fac:1, /* filter out by facilities[] */ decode:1, /* use "facility: level: " prefix */ @@ -197,6 +198,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out) " -t, --notime don't print messages timestamp\n" " -u, --userspace display userspace messages\n" " -V, --version output version information and exit\n" + " -w, --follow wait for new messages\n" " -x, --decode decode facility and level to readable string\n"), out); fputs(_("\nSupported log facilities:\n"), out); @@ -770,7 +772,12 @@ static void print_buffer(struct dmesg_control *ctl, static int init_kmsg(struct dmesg_control *ctl) { - ctl->kmsg = open("/dev/kmsg", O_RDONLY|O_NONBLOCK); + int mode = O_RDONLY; + + if (!ctl->follow) + mode |= O_NONBLOCK; + + ctl->kmsg = open("/dev/kmsg", mode); if (ctl->kmsg < 0) return -1; @@ -913,9 +920,11 @@ int main(int argc, char *argv[]) EXCL_READ_CLEAR, EXCL_CONSOLE_LEVEL, EXCL_CONSOLE_ON, - EXCL_CONSOLE_OFF + EXCL_CONSOLE_OFF, + EXCL_FOLLOW, + EXCL_SYSLOG }; - int excl_any = EXCL_NONE; + int excl_any = EXCL_NONE, excl_sys = EXCL_NONE; static const struct option longopts[] = { { "buffer-size", required_argument, NULL, 's' }, @@ -926,6 +935,7 @@ int main(int argc, char *argv[]) { "decode", no_argument, NULL, 'x' }, { "file", required_argument, NULL, 'F' }, { "facility", required_argument, NULL, 'f' }, + { "follow", no_argument, NULL, 'w' }, { "help", no_argument, NULL, 'h' }, { "kernel", no_argument, NULL, 'k' }, { "level", required_argument, NULL, 'l' }, @@ -945,7 +955,7 @@ int main(int argc, char *argv[]) textdomain(PACKAGE); atexit(close_stdout); - while ((c = getopt_long(argc, argv, "CcDdEF:f:hkl:n:rSs:TtuVx", + while ((c = getopt_long(argc, argv, "CcDdEF:f:hkl:n:rSs:TtuVwx", longopts, NULL)) != -1) { switch (c) { case 'C': @@ -999,6 +1009,7 @@ int main(int argc, char *argv[]) ctl.raw = 1; break; case 'S': + exclusive_option(&excl_sys, EXCL_SYSLOG, "--{syslog,follow}"); ctl.method = DMESG_METHOD_SYSLOG; break; case 's': @@ -1024,6 +1035,10 @@ int main(int argc, char *argv[]) printf(_("%s from %s\n"), program_invocation_short_name, PACKAGE_STRING); return EXIT_SUCCESS; + case 'w': + exclusive_option(&excl_sys, EXCL_FOLLOW, "--{syslog,follow}"); + ctl.follow = 1; + break; case 'x': ctl.decode = 1; break; |