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dmesg: add --follow feature 

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2012-07-20 14:04:48 +02:00
parent c677ffba97
commit 0fd12a9697
2 changed files with 23 additions and 5 deletions
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3
sys-utils/dmesg.1
View File

@ -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

25
sys-utils/dmesg.c
View File

@ -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;