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util-linux/sys-utils/dmesg.c

1464 lines
36 KiB

/*
* dmesg.c -- Print out the contents of the kernel ring buffer
*
* Copyright (C) 1993 Theodore Ts'o <tytso@athena.mit.edu>
* Copyright (C) 2011 Karel Zak <kzak@redhat.com>
*
* This program comes with ABSOLUTELY NO WARRANTY.
*/
#include <linux/unistd.h>
#include <stdio.h>
#include <getopt.h>
#include <stdlib.h>
#include <sys/klog.h>
#include <sys/syslog.h>
#include <sys/time.h>
#include <sys/sysinfo.h>
#include <ctype.h>
#include <time.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "c.h"
#include "colors.h"
#include "nls.h"
#include "strutils.h"
#include "xalloc.h"
#include "widechar.h"
#include "all-io.h"
#include "bitops.h"
#include "closestream.h"
#include "optutils.h"
#include "timeutils.h"
#include "monotonic.h"
#include "mangle.h"
#include "pager.h"
/* Close the log. Currently a NOP. */
#define SYSLOG_ACTION_CLOSE 0
/* Open the log. Currently a NOP. */
#define SYSLOG_ACTION_OPEN 1
/* Read from the log. */
#define SYSLOG_ACTION_READ 2
/* Read all messages remaining in the ring buffer. (allowed for non-root) */
#define SYSLOG_ACTION_READ_ALL 3
/* Read and clear all messages remaining in the ring buffer */
#define SYSLOG_ACTION_READ_CLEAR 4
/* Clear ring buffer. */
#define SYSLOG_ACTION_CLEAR 5
/* Disable printk's to console */
#define SYSLOG_ACTION_CONSOLE_OFF 6
/* Enable printk's to console */
#define SYSLOG_ACTION_CONSOLE_ON 7
/* Set level of messages printed to console */
#define SYSLOG_ACTION_CONSOLE_LEVEL 8
/* Return number of unread characters in the log buffer */
#define SYSLOG_ACTION_SIZE_UNREAD 9
/* Return size of the log buffer */
#define SYSLOG_ACTION_SIZE_BUFFER 10
/*
* Color scheme
*/
struct dmesg_color {
const char *scheme; /* name used in termina-colors.d/dmesg.scheme */
const char *dflt; /* default color ESC sequence */
};
enum {
DMESG_COLOR_SUBSYS,
DMESG_COLOR_TIME,
DMESG_COLOR_TIMEBREAK,
DMESG_COLOR_ALERT,
DMESG_COLOR_CRIT,
DMESG_COLOR_ERR,
DMESG_COLOR_WARN,
DMESG_COLOR_SEGFAULT
};
static const struct dmesg_color colors[] =
{
[DMESG_COLOR_SUBSYS] = { "subsys", UL_COLOR_BROWN },
[DMESG_COLOR_TIME] = { "time", UL_COLOR_GREEN },
[DMESG_COLOR_TIMEBREAK] = { "timebreak",UL_COLOR_GREEN UL_COLOR_BOLD },
[DMESG_COLOR_ALERT] = { "alert", UL_COLOR_REVERSE UL_COLOR_RED },
[DMESG_COLOR_CRIT] = { "crit", UL_COLOR_BOLD UL_COLOR_RED },
[DMESG_COLOR_ERR] = { "err", UL_COLOR_RED },
[DMESG_COLOR_WARN] = { "warn", UL_COLOR_BOLD },
[DMESG_COLOR_SEGFAULT] = { "segfault", UL_COLOR_HALFBRIGHT UL_COLOR_RED }
};
#define dmesg_enable_color(_id) \
color_scheme_enable(colors[_id].scheme, colors[_id].dflt);
/*
* Priority and facility names
*/
struct dmesg_name {
const char *name;
const char *help;
};
/*
* Priority names -- based on sys/syslog.h
*/
static const struct dmesg_name level_names[] =
{
[LOG_EMERG] = { "emerg", N_("system is unusable") },
[LOG_ALERT] = { "alert", N_("action must be taken immediately") },
[LOG_CRIT] = { "crit", N_("critical conditions") },
[LOG_ERR] = { "err", N_("error conditions") },
[LOG_WARNING] = { "warn", N_("warning conditions") },
[LOG_NOTICE] = { "notice",N_("normal but significant condition") },
[LOG_INFO] = { "info", N_("informational") },
[LOG_DEBUG] = { "debug", N_("debug-level messages") }
};
/*
* sys/syslog.h uses (f << 3) for all facility codes.
* We want to use the codes as array indexes, so shift back...
*
* Note that libc LOG_FAC() macro returns the base codes, not the
* shifted code :-)
*/
#define FAC_BASE(f) ((f) >> 3)
static const struct dmesg_name facility_names[] =
{
[FAC_BASE(LOG_KERN)] = { "kern", N_("kernel messages") },
[FAC_BASE(LOG_USER)] = { "user", N_("random user-level messages") },
[FAC_BASE(LOG_MAIL)] = { "mail", N_("mail system") },
[FAC_BASE(LOG_DAEMON)] = { "daemon", N_("system daemons") },
[FAC_BASE(LOG_AUTH)] = { "auth", N_("security/authorization messages") },
[FAC_BASE(LOG_SYSLOG)] = { "syslog", N_("messages generated internally by syslogd") },
[FAC_BASE(LOG_LPR)] = { "lpr", N_("line printer subsystem") },
[FAC_BASE(LOG_NEWS)] = { "news", N_("network news subsystem") },
[FAC_BASE(LOG_UUCP)] = { "uucp", N_("UUCP subsystem") },
[FAC_BASE(LOG_CRON)] = { "cron", N_("clock daemon") },
[FAC_BASE(LOG_AUTHPRIV)] = { "authpriv", N_("security/authorization messages (private)") },
[FAC_BASE(LOG_FTP)] = { "ftp", N_("FTP daemon") },
};
/* supported methods to read message buffer
*/
enum {
DMESG_METHOD_KMSG, /* read messages from /dev/kmsg (default) */
DMESG_METHOD_SYSLOG, /* klogctl() buffer */
DMESG_METHOD_MMAP /* mmap file with records (see --file) */
};
enum {
DMESG_TIMEFTM_NONE = 0,
DMESG_TIMEFTM_CTIME, /* [ctime] */
DMESG_TIMEFTM_CTIME_DELTA, /* [ctime <delta>] */
DMESG_TIMEFTM_DELTA, /* [<delta>] */
DMESG_TIMEFTM_RELTIME, /* [relative] */
DMESG_TIMEFTM_TIME, /* [time] */
DMESG_TIMEFTM_TIME_DELTA, /* [time <delta>] */
DMESG_TIMEFTM_ISO8601 /* 2013-06-13T22:11:00,123456+0100 */
};
#define is_timefmt(c, f) ((c)->time_fmt == (DMESG_TIMEFTM_ ##f))
struct dmesg_control {
/* bit arrays -- see include/bitops.h */
char levels[ARRAY_SIZE(level_names) / NBBY + 1];
char facilities[ARRAY_SIZE(facility_names) / NBBY + 1];
struct timeval lasttime; /* last printed timestamp */
struct tm lasttm; /* last localtime */
struct timeval boot_time; /* system boot time */
int action; /* SYSLOG_ACTION_* */
int method; /* DMESG_METHOD_* */
size_t bufsize; /* size of syslog buffer */
int kmsg; /* /dev/kmsg file descriptor */
ssize_t kmsg_first_read;/* initial read() return code */
char kmsg_buf[BUFSIZ];/* buffer to read kmsg data */
/*
* For the --file option we mmap whole file. The unnecessary (already
* printed) pages are always unmapped. The result is that we have in
* memory only the currently used page(s).
*/
char *filename;
char *mmap_buff;
size_t pagesize;
unsigned int time_fmt; /* time format */
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 */
pager:1, /* pipe output into a pager */
color:1; /* colorize messages */
int indent; /* due to timestamps if newline */
};
struct dmesg_record {
const char *mesg;
size_t mesg_size;
int level;
int facility;
struct timeval tv;
const char *next; /* buffer with next unparsed record */
size_t next_size; /* size of the next buffer */
};
#define INIT_DMESG_RECORD(_r) do { \
(_r)->mesg = NULL; \
(_r)->mesg_size = 0; \
(_r)->facility = -1; \
(_r)->level = -1; \
(_r)->tv.tv_sec = 0; \
(_r)->tv.tv_usec = 0; \
} while (0)
static int read_kmsg(struct dmesg_control *ctl);
static int set_level_color(int log_level, const char *mesg, size_t mesgsz)
{
int id = -1;
switch (log_level) {
case LOG_ALERT:
id = DMESG_COLOR_ALERT;
break;
case LOG_CRIT:
id = DMESG_COLOR_CRIT;
break;
case LOG_ERR:
id = DMESG_COLOR_ERR;
break;
case LOG_WARNING:
id = DMESG_COLOR_WARN;
break;
default:
break;
}
/* well, sometimes the messages contains important keywords, but in
* non-warning/error messages
*/
if (id < 0 && memmem(mesg, mesgsz, "segfault at", 11))
id = DMESG_COLOR_SEGFAULT;
if (id >= 0)
dmesg_enable_color(id);
return id >= 0 ? 0 : -1;
}
static void __attribute__((__noreturn__)) usage(FILE *out)
{
size_t i;
fputs(USAGE_HEADER, out);
fprintf(out, _(" %s [options]\n"), program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("Display or control the kernel ring buffer.\n"), out);
fputs(USAGE_OPTIONS, out);
fputs(_(" -C, --clear clear the kernel ring buffer\n"), out);
fputs(_(" -c, --read-clear read and clear all messages\n"), out);
fputs(_(" -D, --console-off disable printing messages to console\n"), out);
fputs(_(" -E, --console-on enable printing messages to console\n"), out);
fputs(_(" -F, --file <file> use the file instead of the kernel log buffer\n"), out);
fputs(_(" -f, --facility <list> restrict output to defined facilities\n"), out);
fputs(_(" -H, --human human readable output\n"), out);
fputs(_(" -k, --kernel display kernel messages\n"), out);
fputs(_(" -L, --color[=<when>] colorize messages (auto, always or never)\n"), out);
fprintf(out,
" %s\n", USAGE_COLORS_DEFAULT);
fputs(_(" -l, --level <list> restrict output to defined levels\n"), out);
fputs(_(" -n, --console-level <level> set level of messages printed to console\n"), out);
fputs(_(" -P, --nopager do not pipe output into a pager\n"), out);
fputs(_(" -r, --raw print the raw message buffer\n"), out);
fputs(_(" -S, --syslog force to use syslog(2) rather than /dev/kmsg\n"), out);
fputs(_(" -s, --buffer-size <size> buffer size to query the kernel ring buffer\n"), out);
fputs(_(" -u, --userspace display userspace messages\n"), out);
fputs(_(" -w, --follow wait for new messages\n"), out);
fputs(_(" -x, --decode decode facility and level to readable string\n"), out);
fputs(_(" -d, --show-delta show time delta between printed messages\n"), out);
fputs(_(" -e, --reltime show local time and time delta in readable format\n"), out);
fputs(_(" -T, --ctime show human-readable timestamp (may be inaccurate!)\n"), out);
fputs(_(" -t, --notime don't show any timestamp with messages\n"), out);
fputs(_(" --time-format <format> show timestamp using the given format:\n"
" [delta|reltime|ctime|notime|iso]\n"
"Suspending/resume will make ctime and iso timestamps inaccurate.\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fputs(_("\nSupported log facilities:\n"), out);
for (i = 0; i < ARRAY_SIZE(level_names); i++)
fprintf(out, " %7s - %s\n",
facility_names[i].name,
_(facility_names[i].help));
fputs(_("\nSupported log levels (priorities):\n"), out);
for (i = 0; i < ARRAY_SIZE(level_names); i++)
fprintf(out, " %7s - %s\n",
level_names[i].name,
_(level_names[i].help));
fputs(USAGE_SEPARATOR, out);
fprintf(out, USAGE_MAN_TAIL("dmesg(1)"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
/*
* LEVEL ::= <number> | <name>
* <number> ::= @len is set: number in range <0..N>, where N < ARRAY_SIZE(level_names)
* ::= @len not set: number in range <1..N>, where N <= ARRAY_SIZE(level_names)
* <name> ::= case-insensitive text
*
* Note that @len argument is not set when parsing "-n <level>" command line
* option. The console_level is interpreted as "log level less than the value".
*
* For example "dmesg -n 8" or "dmesg -n debug" enables debug console log
* level by klogctl(SYSLOG_ACTION_CONSOLE_LEVEL, NULL, 8). The @str argument
* has to be parsed to number in range <1..8>.
*/
static int parse_level(const char *str, size_t len)
{
int offset = 0;
if (!str)
return -1;
if (!len) {
len = strlen(str);
offset = 1;
}
errno = 0;
if (isdigit(*str)) {
char *end = NULL;
long x = strtol(str, &end, 10) - offset;
if (!errno && end && end > str && (size_t) (end - str) == len &&
x >= 0 && (size_t) x < ARRAY_SIZE(level_names))
return x + offset;
} else {
size_t i;
for (i = 0; i < ARRAY_SIZE(level_names); i++) {
const char *n = level_names[i].name;
if (strncasecmp(str, n, len) == 0 && *(n + len) == '\0')
return i + offset;
}
}
if (errno)
err(EXIT_FAILURE, _("failed to parse level '%s'"), str);
errx(EXIT_FAILURE, _("unknown level '%s'"), str);
return -1;
}
/*
* FACILITY ::= <number> | <name>
* <number> ::= number in range <0..N>, where N < ARRAY_SIZE(facility_names)
* <name> ::= case-insensitive text
*/
static int parse_facility(const char *str, size_t len)
{
if (!str)
return -1;
if (!len)
len = strlen(str);
errno = 0;
if (isdigit(*str)) {
char *end = NULL;
long x = strtol(str, &end, 10);
if (!errno && end && end > str && (size_t) (end - str) == len &&
x >= 0 && (size_t) x < ARRAY_SIZE(facility_names))
return x;
} else {
size_t i;
for (i = 0; i < ARRAY_SIZE(facility_names); i++) {
const char *n = facility_names[i].name;
if (strncasecmp(str, n, len) == 0 && *(n + len) == '\0')
return i;
}
}
if (errno)
err(EXIT_FAILURE, _("failed to parse facility '%s'"), str);
errx(EXIT_FAILURE, _("unknown facility '%s'"), str);
return -1;
}
/*
* Parses numerical prefix used for all messages in kernel ring buffer.
*
* Priorities/facilities are encoded into a single 32-bit quantity, where the
* bottom 3 bits are the priority (0-7) and the top 28 bits are the facility
* (0-big number).
*
* Note that the number has to end with '>' or ',' char.
*/
static const char *parse_faclev(const char *str, int *fac, int *lev)
{
long num;
char *end = NULL;
if (!str)
return str;
errno = 0;
num = strtol(str, &end, 10);
if (!errno && end && end > str) {
*fac = LOG_FAC(num);
*lev = LOG_PRI(num);
if (*lev < 0 || (size_t) *lev > ARRAY_SIZE(level_names))
*lev = -1;
if (*fac < 0 || (size_t) *fac > ARRAY_SIZE(facility_names))
*fac = -1;
return end + 1; /* skip '<' or ',' */
}
return str;
}
/*
* Parses timestamp from syslog message prefix, expected format:
*
* seconds.microseconds]
*
* the ']' is the timestamp field terminator.
*/
static const char *parse_syslog_timestamp(const char *str0, struct timeval *tv)
{
const char *str = str0;
char *end = NULL;
if (!str0)
return str0;
errno = 0;
tv->tv_sec = strtol(str, &end, 10);
if (!errno && end && *end == '.' && *(end + 1)) {
str = end + 1;
end = NULL;
tv->tv_usec = strtol(str, &end, 10);
}
if (errno || !end || end == str || *end != ']')
return str0;
return end + 1; /* skip ']' */
}
/*
* Parses timestamp from /dev/kmsg, expected formats:
*
* microseconds,
* microseconds;
*
* the ',' is fields separators and ';' items terminator (for the last item)
*/
static const char *parse_kmsg_timestamp(const char *str0, struct timeval *tv)
{
const char *str = str0;
char *end = NULL;
uint64_t usec;
if (!str0)
return str0;
errno = 0;
usec = strtoumax(str, &end, 10);
if (!errno && end && (*end == ';' || *end == ',')) {
tv->tv_usec = usec % 1000000;
tv->tv_sec = usec / 1000000;
} else
return str0;
return end + 1; /* skip separator */
}
static double time_diff(struct timeval *a, struct timeval *b)
{
return (a->tv_sec - b->tv_sec) + (a->tv_usec - b->tv_usec) / 1E6;
}
static int get_syslog_buffer_size(void)
{
int n = klogctl(SYSLOG_ACTION_SIZE_BUFFER, NULL, 0);
return n > 0 ? n : 0;
}
/*
* Reads messages from regular file by mmap
*/
static ssize_t mmap_file_buffer(struct dmesg_control *ctl, char **buf)
{
struct stat st;
int fd;
if (!ctl->filename)
return -1;
fd = open(ctl->filename, O_RDONLY);
if (fd < 0)
err(EXIT_FAILURE, _("cannot open %s"), ctl->filename);
if (fstat(fd, &st))
err(EXIT_FAILURE, _("stat of %s failed"), ctl->filename);
*buf = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
if (*buf == MAP_FAILED)
err(EXIT_FAILURE, _("cannot mmap: %s"), ctl->filename);
ctl->mmap_buff = *buf;
ctl->pagesize = getpagesize();
close(fd);
return st.st_size;
}
/*
* Reads messages from kernel ring buffer by klogctl()
*/
static ssize_t read_syslog_buffer(struct dmesg_control *ctl, char **buf)
{
size_t sz;
int rc = -1;
if (ctl->bufsize) {
sz = ctl->bufsize + 8;
*buf = xmalloc(sz * sizeof(char));
rc = klogctl(ctl->action, *buf, sz);
} else {
sz = 16392;
while (1) {
*buf = xmalloc(sz * sizeof(char));
rc = klogctl(SYSLOG_ACTION_READ_ALL, *buf, sz);
if (rc < 0)
break;
if ((size_t) rc != sz || sz > (1 << 28))
break;
free(*buf);
*buf = NULL;
sz *= 4;
}
if (rc > 0 && ctl->action == SYSLOG_ACTION_READ_CLEAR)
rc = klogctl(SYSLOG_ACTION_READ_CLEAR, *buf, sz);
}
return rc;
}
/*
* Top level function to read messages
*/
static ssize_t read_buffer(struct dmesg_control *ctl, char **buf)
{
ssize_t n = -1;
switch (ctl->method) {
case DMESG_METHOD_MMAP:
n = mmap_file_buffer(ctl, buf);
break;
case DMESG_METHOD_SYSLOG:
if (!ctl->bufsize)
ctl->bufsize = get_syslog_buffer_size();
n = read_syslog_buffer(ctl, buf);
break;
case DMESG_METHOD_KMSG:
/*
* Since kernel 3.5.0
*/
n = read_kmsg(ctl);
if (n == 0 && ctl->action == SYSLOG_ACTION_READ_CLEAR)
n = klogctl(SYSLOG_ACTION_CLEAR, NULL, 0);
break;
default:
abort(); /* impossible method -> drop core */
}
return n;
}
static int fwrite_hex(const char *buf, size_t size, FILE *out)
{
size_t i;
for (i = 0; i < size; i++) {
int rc = fprintf(out, "\\x%02x", buf[i]);
if (rc < 0)
return rc;
}
return 0;
}
/*
* Prints to 'out' and non-printable chars are replaced with \x<hex> sequences.
*/
static void safe_fwrite(const char *buf, size_t size, int indent, FILE *out)
{
size_t i;
#ifdef HAVE_WIDECHAR
mbstate_t s;
memset(&s, 0, sizeof (s));
#endif
for (i = 0; i < size; i++) {
const char *p = buf + i;
int rc, hex = 0;
size_t len;
#ifdef HAVE_WIDECHAR
wchar_t wc;
len = mbrtowc(&wc, p, size - i, &s);
if (len == 0) /* L'\0' */
return;
if (len == (size_t)-1 || len == (size_t)-2) { /* invalid sequence */
memset(&s, 0, sizeof (s));
len = hex = 1;
} else if (len > 1 && !iswprint(wc)) { /* non-printable multibyte */
hex = 1;
}
i += len - 1;
#else
len = 1;
if (!isprint((unsigned int) *p) &&
!isspace((unsigned int) *p)) /* non-printable */
hex = 1;
#endif
if (hex)
rc = fwrite_hex(p, len, out);
else if (*p == '\n' && *(p + 1) && indent) {
rc = fwrite(p, 1, len, out) != len;
if (fprintf(out, "%*s", indent, "") != indent)
rc |= 1;
}
else
rc = fwrite(p, 1, len, out) != len;
if (rc != 0) {
if (errno != EPIPE)
err(EXIT_FAILURE, _("write failed"));
exit(EXIT_SUCCESS);
}
}
}
static const char *skip_item(const char *begin, const char *end, const char *sep)
{
while (begin < end) {
int c = *begin++;
if (c == '\0' || strchr(sep, c))
break;
}
return begin;
}
/*
* Parses one record from syslog(2) buffer
*/
static int get_next_syslog_record(struct dmesg_control *ctl,
struct dmesg_record *rec)
{
size_t i;
const char *begin = NULL;
if (ctl->method != DMESG_METHOD_MMAP &&
ctl->method != DMESG_METHOD_SYSLOG)
return -1;
if (!rec->next || !rec->next_size)
return 1;
INIT_DMESG_RECORD(rec);
/*
* Unmap already printed file data from memory
*/
if (ctl->mmap_buff && (size_t) (rec->next - ctl->mmap_buff) > ctl->pagesize) {
void *x = ctl->mmap_buff;
ctl->mmap_buff += ctl->pagesize;
munmap(x, ctl->pagesize);
}
for (i = 0; i < rec->next_size; i++) {
const char *p = rec->next + i;
const char *end = NULL;
if (!begin)
begin = p;
if (i + 1 == rec->next_size) {
end = p + 1;
i++;
} else if (*p == '\n' && *(p + 1) == '<')
end = p;
if (begin && !*begin)
begin = NULL; /* zero(s) at the end of the buffer? */
if (!begin || !end)
continue;
if (end <= begin)
continue; /* error or empty line? */
if (*begin == '<') {
if (ctl->fltr_lev || ctl->fltr_fac || ctl->decode || ctl->color)
begin = parse_faclev(begin + 1, &rec->facility,
&rec->level);
else
begin = skip_item(begin, end, ">");
}
if (*begin == '[' && (*(begin + 1) == ' ' ||
isdigit(*(begin + 1)))) {
if (!is_timefmt(ctl, NONE))
begin = parse_syslog_timestamp(begin + 1, &rec->tv);
else
begin = skip_item(begin, end, "]");
if (begin < end && *begin == ' ')
begin++;
}
rec->mesg = begin;
rec->mesg_size = end - begin;
rec->next_size -= end - rec->next;
rec->next = rec->next_size > 0 ? end + 1 : NULL;
if (rec->next_size > 0)
rec->next_size--;
return 0;
}
return 1;
}
static int accept_record(struct dmesg_control *ctl, struct dmesg_record *rec)
{
if (ctl->fltr_lev && (rec->facility < 0 ||
!isset(ctl->levels, rec->level)))
return 0;
if (ctl->fltr_fac && (rec->facility < 0 ||
!isset(ctl->facilities, rec->facility)))
return 0;
return 1;
}
static void raw_print(struct dmesg_control *ctl, const char *buf, size_t size)
{
int lastc = '\n';
if (!ctl->mmap_buff) {
/*
* Print whole ring buffer
*/
safe_fwrite(buf, size, 0, stdout);
lastc = buf[size - 1];
} else {
/*
* Print file in small chunks to save memory
*/
while (size) {
size_t sz = size > ctl->pagesize ? ctl->pagesize : size;
char *x = ctl->mmap_buff;
safe_fwrite(x, sz, 0, stdout);
lastc = x[sz - 1];
size -= sz;
ctl->mmap_buff += sz;
munmap(x, sz);
}
}
if (lastc != '\n')
putchar('\n');
}
static struct tm *record_localtime(struct dmesg_control *ctl,
struct dmesg_record *rec,
struct tm *tm)
{
time_t t = ctl->boot_time.tv_sec + rec->tv.tv_sec;
return localtime_r(&t, tm);
}
static char *record_ctime(struct dmesg_control *ctl,
struct dmesg_record *rec,
char *buf, size_t bufsiz)
{
struct tm tm;
record_localtime(ctl, rec, &tm);
if (strftime(buf, bufsiz, "%a %b %e %H:%M:%S %Y", &tm) == 0)
*buf = '\0';
return buf;
}
static char *short_ctime(struct tm *tm, char *buf, size_t bufsiz)
{
if (strftime(buf, bufsiz, "%b%e %H:%M", tm) == 0)
*buf = '\0';
return buf;
}
static char *iso_8601_time(struct dmesg_control *ctl, struct dmesg_record *rec,
char *buf, size_t bufsz)
{
struct timeval tv = {
.tv_sec = ctl->boot_time.tv_sec + rec->tv.tv_sec,
.tv_usec = rec->tv.tv_usec
};
if (strtimeval_iso(&tv, ISO_8601_DATE|ISO_8601_TIME|ISO_8601_COMMAUSEC|
ISO_8601_TIMEZONE,
buf, bufsz) != 0)
return NULL;
return buf;
}
static double record_count_delta(struct dmesg_control *ctl,
struct dmesg_record *rec)
{
double delta = 0;
if (timerisset(&ctl->lasttime))
delta = time_diff(&rec->tv, &ctl->lasttime);
ctl->lasttime = rec->tv;
return delta;
}
static const char *get_subsys_delimiter(const char *mesg, size_t mesg_size)
{
const char *p = mesg;
size_t sz = mesg_size;
while (sz > 0) {
const char *d = strnchr(p, sz, ':');
if (!d)
return NULL;
sz -= d - p;
if (sz) {
if (isblank(*(d + 1)))
return d;
p = d + 1;
}
}
return NULL;
}
static void print_record(struct dmesg_control *ctl,
struct dmesg_record *rec)
{
char buf[256];
int has_color = 0;
const char *mesg;
size_t mesg_size;
int indent = 0;
if (!accept_record(ctl, rec))
return;
if (!rec->mesg_size) {
putchar('\n');
return;
}
/*
* compose syslog(2) compatible raw output -- used for /dev/kmsg for
* backward compatibility with syslog(2) buffers only
*/
if (ctl->raw) {
ctl->indent = printf("<%d>[%5ld.%06ld] ",
LOG_MAKEPRI(rec->facility, rec->level),
(long) rec->tv.tv_sec,
(long) rec->tv.tv_usec);
goto mesg;
}
/*
* facility : priority :
*/
if (ctl->decode &&
-1 < rec->level && rec->level < (int) ARRAY_SIZE(level_names) &&
-1 < rec->facility && rec->facility < (int) ARRAY_SIZE(facility_names))
indent = printf("%-6s:%-6s: ", facility_names[rec->facility].name,
level_names[rec->level].name);
if (ctl->color)
dmesg_enable_color(DMESG_COLOR_TIME);
switch (ctl->time_fmt) {
double delta;
struct tm cur;
case DMESG_TIMEFTM_NONE:
ctl->indent = 0;
break;
case DMESG_TIMEFTM_CTIME:
ctl->indent = printf("[%s] ", record_ctime(ctl, rec, buf, sizeof(buf)));
break;
case DMESG_TIMEFTM_CTIME_DELTA:
ctl->indent = printf("[%s <%12.06f>] ",
record_ctime(ctl, rec, buf, sizeof(buf)),
record_count_delta(ctl, rec));
break;
case DMESG_TIMEFTM_DELTA:
ctl->indent = printf("[<%12.06f>] ", record_count_delta(ctl, rec));
break;
case DMESG_TIMEFTM_RELTIME:
record_localtime(ctl, rec, &cur);
delta = record_count_delta(ctl, rec);
if (cur.tm_min != ctl->lasttm.tm_min ||
cur.tm_hour != ctl->lasttm.tm_hour ||
cur.tm_yday != ctl->lasttm.tm_yday) {
dmesg_enable_color(DMESG_COLOR_TIMEBREAK);
ctl->indent = printf("[%s] ", short_ctime(&cur, buf, sizeof(buf)));
} else {
if (delta < 10)
ctl->indent = printf("[ %+8.06f] ", delta);
else
ctl->indent = printf("[ %+9.06f] ", delta);
}
ctl->lasttm = cur;
break;
case DMESG_TIMEFTM_TIME:
ctl->indent = printf("[%5ld.%06ld] ",
(long)rec->tv.tv_sec, (long)rec->tv.tv_usec);
break;
case DMESG_TIMEFTM_TIME_DELTA:
ctl->indent = printf("[%5ld.%06ld <%12.06f>] ", (long)rec->tv.tv_sec,
(long)rec->tv.tv_usec, record_count_delta(ctl, rec));
break;
case DMESG_TIMEFTM_ISO8601:
ctl->indent = printf("%s ", iso_8601_time(ctl, rec, buf, sizeof(buf)));
break;
default:
abort();
}
ctl->indent += indent;
if (ctl->color)
color_disable();
mesg:
mesg = rec->mesg;
mesg_size = rec->mesg_size;
/* Colorize output */
if (ctl->color) {
/* subsystem prefix */
const char *subsys = get_subsys_delimiter(mesg, mesg_size);
if (subsys) {
dmesg_enable_color(DMESG_COLOR_SUBSYS);
safe_fwrite(mesg, subsys - mesg, ctl->indent, stdout);
color_disable();
mesg_size -= subsys - mesg;
mesg = subsys;
}
/* error, alert .. etc. colors */
has_color = set_level_color(rec->level, mesg, mesg_size) == 0;
safe_fwrite(mesg, mesg_size, ctl->indent, stdout);
if (has_color)
color_disable();
} else
safe_fwrite(mesg, mesg_size, ctl->indent, stdout);
if (*(mesg + mesg_size - 1) != '\n')
putchar('\n');
}
/*
* Prints the 'buf' kernel ring buffer; the messages are filtered out according
* to 'levels' and 'facilities' bitarrays.
*/
static void print_buffer(struct dmesg_control *ctl,
const char *buf, size_t size)
{
struct dmesg_record rec = { .next = buf, .next_size = size };
if (ctl->raw) {
raw_print(ctl, buf, size);
return;
}
while (get_next_syslog_record(ctl, &rec) == 0)
print_record(ctl, &rec);
}
static ssize_t read_kmsg_one(struct dmesg_control *ctl)
{
ssize_t size;
/* kmsg returns EPIPE if record was modified while reading */
do {
size = read(ctl->kmsg, ctl->kmsg_buf,
sizeof(ctl->kmsg_buf) - 1);
} while (size < 0 && errno == EPIPE);
return size;
}
static int init_kmsg(struct dmesg_control *ctl)
{
int mode = O_RDONLY;
if (!ctl->follow)
mode |= O_NONBLOCK;
else
setlinebuf(stdout);
ctl->kmsg = open("/dev/kmsg", mode);
if (ctl->kmsg < 0)
return -1;
/*
* Seek after the last record available at the time
* the last SYSLOG_ACTION_CLEAR was issued.
*
* ... otherwise SYSLOG_ACTION_CLEAR will have no effect for kmsg.
*/
lseek(ctl->kmsg, 0, SEEK_DATA);
/*
* Old kernels (<3.5) allow to successfully open /dev/kmsg for
* read-only, but read() returns -EINVAL :-(((
*
* Let's try to read the first record. The record is later processed in
* read_kmsg().
*/
ctl->kmsg_first_read = read_kmsg_one(ctl);
if (ctl->kmsg_first_read < 0) {
close(ctl->kmsg);
ctl->kmsg = -1;
return -1;
}
return 0;
}
/*
* /dev/kmsg record format:
*
* faclev,seqnum,timestamp[optional, ...];message\n
* TAGNAME=value
* ...
*
* - fields are separated by ','
* - last field is terminated by ';'
*
*/
#define LAST_KMSG_FIELD(s) (!s || !*s || *(s - 1) == ';')
static int parse_kmsg_record(struct dmesg_control *ctl,
struct dmesg_record *rec,
char *buf,
size_t sz)
{
const char *p = buf, *end;
if (sz == 0 || !buf || !*buf)
return -1;
end = buf + (sz - 1);
INIT_DMESG_RECORD(rec);
while (p < end && isspace(*p))
p++;
/* A) priority and facility */
if (ctl->fltr_lev || ctl->fltr_fac || ctl->decode ||
ctl->raw || ctl->color)
p = parse_faclev(p, &rec->facility, &rec->level);
else
p = skip_item(p, end, ",");
if (LAST_KMSG_FIELD(p))
goto mesg;
/* B) sequence number */
p = skip_item(p, end, ",;");
if (LAST_KMSG_FIELD(p))
goto mesg;
/* C) timestamp */
if (is_timefmt(ctl, NONE))
p = skip_item(p, end, ",;");
else
p = parse_kmsg_timestamp(p, &rec->tv);
if (LAST_KMSG_FIELD(p))
goto mesg;
/* D) optional fields (ignore) */
p = skip_item(p, end, ";");
mesg:
/* E) message text */
rec->mesg = p;
p = skip_item(p, end, "\n");
if (!p)
return -1;
rec->mesg_size = p - rec->mesg;
/*
* Kernel escapes non-printable characters, unfortunately kernel
* definition of "non-printable" is too strict. On UTF8 console we can
* print many chars, so let's decode from kernel.
*/
unhexmangle_to_buffer(rec->mesg, (char *) rec->mesg, rec->mesg_size + 1);
/* F) message tags (ignore) */
return 0;
}
/*
* Note that each read() call for /dev/kmsg returns always one record. It means
* that we don't have to read whole message buffer before the records parsing.
*
* So this function does not compose one huge buffer (like read_syslog_buffer())
* and print_buffer() is unnecessary. All is done in this function.
*
* Returns 0 on success, -1 on error.
*/
static int read_kmsg(struct dmesg_control *ctl)
{
struct dmesg_record rec;
ssize_t sz;
if (ctl->method != DMESG_METHOD_KMSG || ctl->kmsg < 0)
return -1;
/*
* The very first read() call is done in kmsg_init() where we test
* /dev/kmsg usability. The return code from the initial read() is
* stored in ctl->kmsg_first_read;
*/
sz = ctl->kmsg_first_read;
while (sz > 0) {
*(ctl->kmsg_buf + sz) = '\0'; /* for debug messages */
if (parse_kmsg_record(ctl, &rec,
ctl->kmsg_buf, (size_t) sz) == 0)
print_record(ctl, &rec);
sz = read_kmsg_one(ctl);
}
return 0;
}
static int which_time_format(const char *s)
{
if (!strcmp(s, "notime"))
return DMESG_TIMEFTM_NONE;
if (!strcmp(s, "ctime"))
return DMESG_TIMEFTM_CTIME;
if (!strcmp(s, "delta"))
return DMESG_TIMEFTM_DELTA;
if (!strcmp(s, "reltime"))
return DMESG_TIMEFTM_RELTIME;
if (!strcmp(s, "iso"))
return DMESG_TIMEFTM_ISO8601;
errx(EXIT_FAILURE, _("unknown time format: %s"), s);
}
#ifdef TEST_DMESG
static inline int dmesg_get_boot_time(struct timeval *tv)
{
char *str = getenv("DMESG_TEST_BOOTIME");
uintmax_t sec, usec;
if (str && sscanf(str, "%ju.%ju", &sec, &usec) == 2) {
tv->tv_sec = sec;
tv->tv_usec = usec;
return tv->tv_sec >= 0 && tv->tv_usec >= 0 ? 0 : -EINVAL;
}
return get_boot_time(tv);
}
#else
# define dmesg_get_boot_time get_boot_time
#endif
int main(int argc, char *argv[])
{
char *buf = NULL;
int c, nopager = 0;
int console_level = 0;
int klog_rc = 0;
int delta = 0;
ssize_t n;
static struct dmesg_control ctl = {
.filename = NULL,
.action = SYSLOG_ACTION_READ_ALL,
.method = DMESG_METHOD_KMSG,
.kmsg = -1,
.time_fmt = DMESG_TIMEFTM_TIME,
.indent = 0,
};
int colormode = UL_COLORMODE_UNDEF;
enum {
OPT_TIME_FORMAT = CHAR_MAX + 1,
};
static const struct option longopts[] = {
{ "buffer-size", required_argument, NULL, 's' },
{ "clear", no_argument, NULL, 'C' },
{ "color", optional_argument, NULL, 'L' },
{ "console-level", required_argument, NULL, 'n' },
{ "console-off", no_argument, NULL, 'D' },
{ "console-on", no_argument, NULL, 'E' },
{ "decode", no_argument, NULL, 'x' },
{ "file", required_argument, NULL, 'F' },
{ "facility", required_argument, NULL, 'f' },
{ "follow", no_argument, NULL, 'w' },
{ "human", no_argument, NULL, 'H' },
{ "help", no_argument, NULL, 'h' },
{ "kernel", no_argument, NULL, 'k' },
{ "level", required_argument, NULL, 'l' },
{ "syslog", no_argument, NULL, 'S' },
{ "raw", no_argument, NULL, 'r' },
{ "read-clear", no_argument, NULL, 'c' },
{ "reltime", no_argument, NULL, 'e' },
{ "show-delta", no_argument, NULL, 'd' },
{ "ctime", no_argument, NULL, 'T' },
{ "notime", no_argument, NULL, 't' },
{ "nopager", no_argument, NULL, 'P' },
{ "userspace", no_argument, NULL, 'u' },
{ "version", no_argument, NULL, 'V' },
{ "time-format", required_argument, NULL, OPT_TIME_FORMAT },
{ NULL, 0, NULL, 0 }
};
static const ul_excl_t excl[] = { /* rows and cols in in ASCII order */
{ 'C','D','E','c','n','r' }, /* clear,off,on,read-clear,level,raw*/
{ 'H','r' }, /* human, raw */
{ 'L','r' }, /* color, raw */
{ 'S','w' }, /* syslog,follow */
{ 'T','r' }, /* ctime, raw */
{ 'd','r' }, /* delta, raw */
{ 'e','r' }, /* reltime, raw */
{ 'r','x' }, /* raw, decode */
{ 'r','t' }, /* notime, raw */
{ 0 }
};
int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
while ((c = getopt_long(argc, argv, "CcDdEeF:f:HhkL::l:n:iPrSs:TtuVwx",
longopts, NULL)) != -1) {
err_exclusive_options(c, longopts, excl, excl_st);
switch (c) {
case 'C':
ctl.action = SYSLOG_ACTION_CLEAR;
break;
case 'c':
ctl.action = SYSLOG_ACTION_READ_CLEAR;
break;
case 'D':
ctl.action = SYSLOG_ACTION_CONSOLE_OFF;
break;
case 'd':
delta = 1;
break;
case 'E':
ctl.action = SYSLOG_ACTION_CONSOLE_ON;
break;
case 'e':
ctl.time_fmt = DMESG_TIMEFTM_RELTIME;
break;
case 'F':
ctl.filename = optarg;
ctl.method = DMESG_METHOD_MMAP;
break;
case 'f':
ctl.fltr_fac = 1;
if (string_to_bitarray(optarg,
ctl.facilities, parse_facility) < 0)
return EXIT_FAILURE;
break;
case 'H':
ctl.time_fmt = DMESG_TIMEFTM_RELTIME;
colormode = UL_COLORMODE_AUTO;
ctl.pager = 1;
break;
case 'h':
usage(stdout);
break;
case 'k':
ctl.fltr_fac = 1;
setbit(ctl.facilities, FAC_BASE(LOG_KERN));
break;
case 'L':
colormode = UL_COLORMODE_AUTO;
if (optarg)
colormode = colormode_or_err(optarg,
_("unsupported color mode"));
break;
case 'l':
ctl.fltr_lev= 1;
if (string_to_bitarray(optarg,
ctl.levels, parse_level) < 0)
return EXIT_FAILURE;
break;
case 'n':
ctl.action = SYSLOG_ACTION_CONSOLE_LEVEL;
console_level = parse_level(optarg, 0);
break;
case 'P':
nopager = 1;
break;
case 'r':
ctl.raw = 1;
break;
case 'S':
ctl.method = DMESG_METHOD_SYSLOG;
break;
case 's':
ctl.bufsize = strtou32_or_err(optarg,
_("invalid buffer size argument"));
if (ctl.bufsize < 4096)
ctl.bufsize = 4096;
break;
case 'T':
ctl.time_fmt = DMESG_TIMEFTM_CTIME;
break;
case 't':
ctl.time_fmt = DMESG_TIMEFTM_NONE;
break;
case 'u':
ctl.fltr_fac = 1;
for (n = 1; (size_t) n < ARRAY_SIZE(facility_names); n++)
setbit(ctl.facilities, n);
break;
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
case 'w':
ctl.follow = 1;
break;
case 'x':
ctl.decode = 1;
break;
case OPT_TIME_FORMAT:
ctl.time_fmt = which_time_format(optarg);
break;
case '?':
default:
usage(stderr);
}
}
argc -= optind;
argv += optind;
if (argc > 1)
usage(stderr);
if ((is_timefmt(&ctl, RELTIME) ||
is_timefmt(&ctl, CTIME) ||
is_timefmt(&ctl, ISO8601))
&& dmesg_get_boot_time(&ctl.boot_time) != 0)
ctl.time_fmt = DMESG_TIMEFTM_NONE;
if (delta)
switch (ctl.time_fmt) {
case DMESG_TIMEFTM_CTIME:
ctl.time_fmt = DMESG_TIMEFTM_CTIME_DELTA;
break;
case DMESG_TIMEFTM_TIME:
ctl.time_fmt = DMESG_TIMEFTM_TIME_DELTA;
break;
case DMESG_TIMEFTM_ISO8601:
warnx(_("--show-delta is ignored when used together with iso8601 time format"));
break;
default:
ctl.time_fmt = DMESG_TIMEFTM_DELTA;
}
ctl.color = colors_init(colormode, "dmesg") ? 1 : 0;
if (ctl.follow)
nopager = 1;
ctl.pager = nopager ? 0 : ctl.pager;
if (ctl.pager)
pager_redirect();
switch (ctl.action) {
case SYSLOG_ACTION_READ_ALL:
case SYSLOG_ACTION_READ_CLEAR:
if (ctl.method == DMESG_METHOD_KMSG && init_kmsg(&ctl) != 0)
ctl.method = DMESG_METHOD_SYSLOG;
if (ctl.raw
&& ctl.method != DMESG_METHOD_KMSG
&& (ctl.fltr_lev || ctl.fltr_fac))
errx(EXIT_FAILURE, _("--raw can be used together with --level or "
"--facility only when reading messages from /dev/kmsg"));
if (ctl.pager)
pager_redirect();
n = read_buffer(&ctl, &buf);
if (n > 0)
print_buffer(&ctl, buf, n);
if (!ctl.mmap_buff)
free(buf);
if (n < 0)
err(EXIT_FAILURE, _("read kernel buffer failed"));
if (ctl.kmsg >= 0)
close(ctl.kmsg);
break;
case SYSLOG_ACTION_CLEAR:
case SYSLOG_ACTION_CONSOLE_OFF:
case SYSLOG_ACTION_CONSOLE_ON:
klog_rc = klogctl(ctl.action, NULL, 0);
break;
case SYSLOG_ACTION_CONSOLE_LEVEL:
klog_rc = klogctl(ctl.action, NULL, console_level);
break;
default:
errx(EXIT_FAILURE, _("unsupported command"));
break;
}
if (klog_rc)
err(EXIT_FAILURE, _("klogctl failed"));
return EXIT_SUCCESS;
}