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dmesg.c
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dmesg.c
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/*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* dmesg.c -- Print out the contents of the kernel ring buffer
*
* Copyright (C) 1993 Theodore Ts'o <tytso@athena.mit.edu>
* Copyright (C) 2011-2023 Karel Zak <kzak@redhat.com>
*/
#include <stdio.h>
#include <getopt.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.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"
#include "jsonwrt.h"
#include "pathnames.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
#define PID_CHARS_MAX sizeof(stringify_value(LONG_MAX))
#define PID_CHARS_DEFAULT sizeof(stringify_value(INT_MAX))
#define SYSLOG_DEFAULT_CALLER_ID_CHARS sizeof(stringify_value(SHRT_MAX))-1
#define DMESG_CALLER_PREFIX "caller="
#define DMESG_CALLER_PREFIXSZ (sizeof(DMESG_CALLER_PREFIX)-1)
/*
* 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)
#define LOG_RAW_FAC_PRI(fac, pri) ((fac << 3) | pri)
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") },
[FAC_BASE(LOG_FTP) + 1] = { "res0", N_("reserved 0") },
[FAC_BASE(LOG_FTP) + 2] = { "res1", N_("reserved 1") },
[FAC_BASE(LOG_FTP) + 3] = { "res2", N_("reserved 2") },
[FAC_BASE(LOG_FTP) + 4] = { "res3", N_("reserved 3") },
[FAC_BASE(LOG_LOCAL0)] = { "local0", N_("local use 0") },
[FAC_BASE(LOG_LOCAL1)] = { "local1", N_("local use 1") },
[FAC_BASE(LOG_LOCAL2)] = { "local2", N_("local use 2") },
[FAC_BASE(LOG_LOCAL3)] = { "local3", N_("local use 3") },
[FAC_BASE(LOG_LOCAL4)] = { "local4", N_("local use 4") },
[FAC_BASE(LOG_LOCAL5)] = { "local5", N_("local use 5") },
[FAC_BASE(LOG_LOCAL6)] = { "local6", N_("local use 6") },
[FAC_BASE(LOG_LOCAL7)] = { "local7", N_("local use 7") },
};
/* 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 */
__DMESG_TIMEFTM_COUNT
};
#define DMESG_TIMEFTM_DEFAULT DMESG_TIMEFTM_TIME
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 */
usec_t suspended_time; /* time spent in suspended state */
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 */
/*
* the kernel will give EINVAL if we do read() on /proc/kmsg with
* length insufficient for the next message. messages may be up to
* PRINTK_MESSAGE_MAX, which is defined as 2048, so we must be
* able to buffer at least that much in one call
*/
char kmsg_buf[2048]; /* buffer to read kmsg data */
usec_t since; /* filter records by time */
usec_t until; /* filter records by time */
/*
* 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;
size_t ntime_fmts;
unsigned int time_fmts[2 * __DMESG_TIMEFTM_COUNT]; /* time format */
struct ul_jsonwrt jfmt; /* -J formatting */
unsigned int follow:1, /* wait for new messages */
end:1, /* seek to the of buffer */
raw:1, /* raw mode */
noesc:1, /* no escape */
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 */
json:1, /* JSON output */
force_prefix:1; /* force timestamp and decode prefix
on each line */
int indent; /* due to timestamps if newline */
size_t caller_id_size; /* PRINTK_CALLERID max field size */
};
struct dmesg_record {
const char *mesg;
size_t mesg_size;
int level;
int facility;
struct timeval tv;
char caller_id[PID_CHARS_MAX];
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; \
(_r)->caller_id[0] = 0; \
} while (0)
static int process_kmsg(struct dmesg_control *ctl);
static int process_kmsg_file(struct dmesg_control *ctl, char **buf);
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(void)
{
FILE *out = stdout;
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(_(" -K, --kmsg-file <file> use the file in kmsg format\n"), out);
fputs(_(" -f, --facility <list> restrict output to defined facilities\n"), out);
fputs(_(" -H, --human human readable output\n"), out);
fputs(_(" -J, --json use JSON output format\n"), out);
fputs(_(" -k, --kernel display kernel messages\n"), out);
fprintf(out,
_(" -L, --color[=<when>] colorize messages (%s, %s or %s)\n"), "auto", "always", "never");
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(_(" -p, --force-prefix force timestamp output on each line of multi-line messages\n"), out);
fputs(_(" -r, --raw print the raw message buffer\n"), out);
fputs(_(" --noescape don't escape unprintable character\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(_(" -W, --follow-new wait and print only 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|raw]\n"
"Suspending/resume will make ctime and iso timestamps inaccurate.\n"), out);
fputs(_(" --since <time> display the lines since the specified time\n"), out);
fputs(_(" --until <time> display the lines until the specified time\n"), out);
fputs(USAGE_SEPARATOR, out);
fprintf(out, USAGE_HELP_OPTIONS(29));
fputs(_("\nSupported log facilities:\n"), out);
for (i = 0; i < ARRAY_SIZE(facility_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));
fprintf(out, USAGE_MAN_TAIL("dmesg(1)"));
exit(EXIT_SUCCESS);
}
static void reset_time_fmts(struct dmesg_control *ctl)
{
memset(ctl->time_fmts, 0,
__DMESG_TIMEFTM_COUNT * sizeof(*(ctl->time_fmts)));
ctl->time_fmts[0] = DMESG_TIMEFTM_DEFAULT;
}
static int is_time_fmt_set(struct dmesg_control *ctl, unsigned int time_format)
{
size_t i;
if (ctl->ntime_fmts == 0)
return time_format == DMESG_TIMEFTM_DEFAULT;
for (i = 0; i < ctl->ntime_fmts; i++) {
if (ctl->time_fmts[i] == time_format)
return 1;
}
return 0;
}
static void include_time_fmt(struct dmesg_control *ctl, unsigned int time_format)
{
if (ctl->ntime_fmts > 0 && is_time_fmt_set(ctl, time_format))
return;
if (ctl->ntime_fmts < __DMESG_TIMEFTM_COUNT)
ctl->time_fmts[ctl->ntime_fmts++] = time_format;
}
static void exclude_time_fmt(struct dmesg_control *ctl, unsigned int time_format)
{
size_t idx = 0;
while (idx < ctl->ntime_fmts && ctl->time_fmts[idx] != time_format)
idx++;
if (idx < ctl->ntime_fmts && ctl->time_fmts[idx] == time_format) {
while (idx + 1 < ctl->ntime_fmts) {
ctl->time_fmts[idx] = ctl->time_fmts[idx+1];
idx++;
}
ctl->ntime_fmts--;
if (ctl->ntime_fmts == 0)
reset_time_fmts(ctl);
}
}
/*
* 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 % USEC_PER_SEC;
tv->tv_sec = usec / USEC_PER_SEC;
} 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) / (double) USEC_PER_SEC;
}
static int get_syslog_buffer_size(void)
{
int n = klogctl(SYSLOG_ACTION_SIZE_BUFFER, NULL, 0);
return n > 0 ? n : 0;
}
/*
* Get the number of characters needed to hold the maximum number
* of tasks this system supports. This size of string could hold
* a thread id large enough for the highest thread id.
* This is needed to determine the number of characters reserved for
* the PRINTK_CALLER field if it has been configured in the Linux Kernel.
*
* The number of digits sets the max value since the value can't exceed
* a value of that size. The /proc field defined by _PATH_PROC_PIDMAX
* holds the maximum number of PID values that may be ussed by the system,
* so 0 to that value minus one.
*
* For determining the size of the PRINTK_CALLER field, we make the safe
* assumption that the number of threads >= number of cpus. This because
* the PRINTK_CALLER field can hold either a thread id or a CPU id value.
*
* If we can't access the pid max kernel proc entry we assign a default
* field size of 5 characters as that is what the old syslog interface
* uses as the reserved field size. This is justified because 32-bit Linux
* systems are limited to PID values between (0-32767).
*
*/
static size_t max_threads_id_size(void)
{
char taskmax[PID_CHARS_MAX] = {'\0'};
ssize_t rdsize;
int fd;
fd = open(_PATH_PROC_PIDMAX, O_RDONLY);
if (fd == -1)
return PID_CHARS_DEFAULT;
rdsize = read(fd, taskmax, sizeof(taskmax));
close(fd);
if (rdsize == -1)
return PID_CHARS_DEFAULT;
return strnlen(taskmax, sizeof(taskmax));
}
/*
* 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(SYSLOG_ACTION_READ_ALL, *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;
}
}
return rc;
}
/*
* Top level function to read (and print in case of kmesg) messages
*/
static ssize_t process_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);
/* Set number of PID characters for caller_id spacing */
ctl->caller_id_size = SYSLOG_DEFAULT_CALLER_ID_CHARS;
break;
case DMESG_METHOD_KMSG:
if (ctl->filename)
n = process_kmsg_file(ctl, buf);
else
/*
* Since kernel 3.5.0
*/
n = process_kmsg(ctl);
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%02hhx", 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(struct dmesg_control *ctl, const char *buf, size_t size, int indent, FILE *out)
{
size_t i;
#ifdef HAVE_WIDECHAR
mbstate_t s;
wchar_t wc;
memset(&s, 0, sizeof (s));
#endif
for (i = 0; i < size; i++) {
const char *p = buf + i;
int rc, hex = 0;
size_t len = 1;
if (!ctl->noesc) {
if (*p == '\0') {
hex = 1;
goto doprint;
}
#ifdef HAVE_WIDECHAR
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;
i += len - 1;
} else if (len > 1) {
if (!iswprint(wc) && !iswspace(wc)) /* non-printable multibyte */
hex = 1;
i += len - 1;
} else
#endif
{
len = 1;
if (!isprint((unsigned char) *p) &&
!isspace((unsigned char) *p)) /* non-printable */
hex = 1;
}
}
doprint:
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;
}
/*
* Checks to see if the caller (caller id) field is present in the kmsg record.
* This is true if the PRINTK_CALLER config option has been set in the kernel.
*
* If the caller_id is found in the kmsg buffer then return the id and id type
* to the caller in dmesg caller_id. Returns string pointer to next value.
*
*/
static const char *parse_callerid(const char *p_str, const char *end,
struct dmesg_record *p_drec)
{
const char *p_after;
const char *p_next;
size_t cid_size;
char *p_scn;
char *p_cid;
/* Check for PRINTK_CALLER prefix, must be before msg text */
p_cid = strstr(p_str, DMESG_CALLER_PREFIX);
p_scn = strchr(p_str, ';');
if (p_cid != NULL && p_drec != NULL && p_scn != NULL && p_cid < p_scn) {
p_next = p_cid + DMESG_CALLER_PREFIXSZ;
p_after = skip_item(p_next, end, ",;");
cid_size = p_after - p_next;
if (cid_size < sizeof(p_drec->caller_id))
xstrncpy(p_drec->caller_id, p_next, cid_size);
else
return p_str;
return p_after;
}
return p_str;
}
/*
* 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 || ctl->json)
begin = parse_faclev(begin + 1, &rec->facility,
&rec->level);
else
begin = skip_item(begin, end, ">");
}
if (*begin == '[' && (*(begin + 1) == ' ' ||
isdigit(*(begin + 1)))) {
if (!is_time_fmt_set(ctl, DMESG_TIMEFTM_NONE))
begin = parse_syslog_timestamp(begin + 1, &rec->tv);
else
begin = skip_item(begin, end, "]");
if (begin < end && *begin == ' ')
begin++;
}
if (*begin == '[' && (*(begin + 1) == ' ' ||
(*(begin + 1) == 'T' || *(begin + 1) == 'C'))) {
const char *start = begin + 1;
size_t id_size;
while (start < end && *start == ' ')
start++;
begin = skip_item(begin, end, "]");
id_size = begin - start;
if (id_size < sizeof(rec->caller_id))
xstrncpy(rec->caller_id, start, id_size);
rec->mesg = begin < end ? begin + 1 : NULL;
rec->mesg_size = begin < end ? end - begin - 1 : 0;
} else {
rec->mesg = begin;
rec->mesg_size = end - begin;
}
/* Don't count \n from the last message to the message size */
if (*end != '\n' && *(end - 1) == '\n')
rec->mesg_size--;
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 usec_t record_time(struct dmesg_control *ctl, struct dmesg_record *rec)
{
return timeval_to_usec(&ctl->boot_time) +
ctl->suspended_time +
timeval_to_usec(&rec->tv);
}
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;
if (ctl->since && ctl->since >= record_time(ctl, rec))
return 0;
if (ctl->until && ctl->until <= record_time(ctl, rec))
return 0;
return 1;
}
static void raw_print(struct dmesg_control *ctl, const char *buf, size_t size)
{