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authorElliott Hughes <enh@google.com>2017-03-25 13:08:20 -0700
committerRob Landley <rob@landley.net>2017-04-03 15:31:17 -0500
commit385a237e40f6d9dab2829611d124a09ee80c5e17 (patch)
tree92b1e4dfef894d77bd6fd13157c1e10c3740eb07 /toys
parent36beb530a79fff3d82df2bd1550693ca10d808e8 (diff)
downloadtoybox-385a237e40f6d9dab2829611d124a09ee80c5e17.tar.gz
Implement dmesg -T.
Also refactor so that legacy mode gets all the new functionality too, and add -S to make it easier to test legacy mode on 3.5 or newer kernels (at least on the host; on Android the syslog(2) system call is no longer allowed). Bug: http://b/36090178
Diffstat (limited to 'toys')
-rw-r--r--toys/pending/dmesg.c153
1 files changed, 88 insertions, 65 deletions
diff --git a/toys/pending/dmesg.c b/toys/pending/dmesg.c
index 40834b0c..198f64a1 100644
--- a/toys/pending/dmesg.c
+++ b/toys/pending/dmesg.c
@@ -5,13 +5,13 @@
* http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/dmesg.html
// We care that FLAG_c is 1, so keep c at the end.
-USE_DMESG(NEWTOY(dmesg, "w(follow)Ctrs#<1n#c[!tr][!Cc]", TOYFLAG_BIN))
+USE_DMESG(NEWTOY(dmesg, "w(follow)CSTtrs#<1n#c[!Ttr][!Cc]", TOYFLAG_BIN))
config DMESG
bool "dmesg"
default n
help
- usage: dmesg [-Cc] [-r|-t] [-n LEVEL] [-s SIZE] [-w]
+ usage: dmesg [-Cc] [-r|-t|-T] [-n LEVEL] [-s SIZE] [-w]
Print or control the kernel ring buffer.
@@ -19,8 +19,10 @@ config DMESG
-c Clear ring buffer after printing
-n Set kernel logging LEVEL (1-9)
-r Raw output (with <level markers>)
+ -S Use syslog(2) rather than /dev/kmsg
-s Show the last SIZE many bytes
- -t Don't print kernel's timestamps
+ -T Show human-readable timestamps
+ -t Don't print timestamps
-w Keep waiting for more output (aka --follow)
*/
@@ -32,9 +34,77 @@ GLOBALS(
long level;
long size;
- int color;
+ int use_color;
+ struct sysinfo info;
)
+static void color(int c)
+{
+ if (TT.use_color) printf("\033[%dm", c);
+}
+
+static void format_message(char *msg, int new) {
+ unsigned long long time_s;
+ unsigned long long time_us;
+ int facpri, subsystem, pos;
+ char *p, *text;
+
+ // The new /dev/kmsg and the old syslog(2) formats differ slightly.
+ if (new) {
+ if (sscanf(msg, "%u,%*u,%llu,%*[^;];%n", &facpri, &time_us, &pos) != 2)
+ return;
+
+ time_s = time_us/1000000;
+ time_us %= 1000000;
+ } else {
+ if (sscanf(msg, "<%u>[%llu.%llu] %n",
+ &facpri, &time_s, &time_us, &pos) != 3)
+ return;
+ }
+
+ // Drop extras after end of message text.
+ text = msg + pos;
+ if ((p = strchr(text, '\n'))) *p = 0;
+
+ // Is there a subsystem? (The ": " is just a convention.)
+ p = strstr(text, ": ");
+ subsystem = p ? (p - text) : 0;
+
+ // "Raw" is a lie for /dev/kmsg. In practice, it just means we show the
+ // syslog facility/priority at the start of each line to emulate the
+ // historical syslog(2) format.
+ if (toys.optflags&FLAG_r) printf("<%d>", facpri);
+
+ // Format the time.
+ if (!(toys.optflags&FLAG_t)) {
+ color(32);
+ if (toys.optflags&FLAG_T) {
+ time_t t = (time(NULL) - TT.info.uptime) + time_s;
+ char *ts = ctime(&t);
+
+ printf("[%.*s] ", (int)(strlen(ts) - 1), ts);
+ } else {
+ printf("[%5lld.%06lld] ", time_s, time_us);
+ }
+ color(0);
+ }
+
+ // Errors (or worse) are shown in red, subsystems are shown in yellow.
+ if (subsystem) {
+ color(33);
+ printf("%.*s", subsystem, text);
+ text += subsystem;
+ color(0);
+ }
+ if (!((facpri&7) <= 3)) xputs(text);
+ else {
+ color(31);
+ printf("%s", text);
+ color(0);
+ xputc('\n');
+ }
+}
+
static int xklogctl(int type, char *buf, int len)
{
int rc = klogctl(type, buf, len);
@@ -55,34 +125,25 @@ static void legacy_mode()
data = to = from = xmalloc(size+1);
data[size = xklogctl(3 + (toys.optflags & FLAG_c), data, size)] = 0;
- // Filter out level markers and optionally time markers
- if (!(toys.optflags & FLAG_r)) while ((from - data) < size) {
- if (from == data || from[-1] == '\n') {
- char *to;
+ // Break into messages (one per line) and send each one to format_message.
+ to = data + size;
+ while (from < to) {
+ char *msg_end = memchr(from, '\n', (to-from));
- if (*from == '<' && (to = strchr(from, '>'))) from = ++to;
- if ((toys.optflags&FLAG_t) && *from == '[' && (to = strchr(from, ']')))
- from = to+1+(to[1]==' ');
- }
- *(to++) = *(from++);
- } else to = data+size;
-
- // Write result. The odds of somebody requesting a buffer of size 3 and
- // getting "<1>" are remote, but don't segfault if they do.
- if (to != data) {
- xwrite(1, data, to-data);
- if (to[-1] != '\n') xputc('\n');
+ if (!msg_end) break;
+ *msg_end = '\0';
+ format_message(from, 0);
+ from = msg_end + 1;
}
- if (CFG_TOYBOX_FREE) free(data);
-}
-static void color(int c)
-{
- if (TT.color) printf("\033[%dm", c);
+ if (CFG_TOYBOX_FREE) free(data);
}
static void print_all(void)
{
+ if (toys.optflags&FLAG_T) sysinfo(&TT.info);
+ if (toys.optflags&FLAG_S) return legacy_mode();
+
// http://kernel.org/doc/Documentation/ABI/testing/dev-kmsg
// Each read returns one message. By default, we block when there are no
@@ -95,9 +156,6 @@ static void print_all(void)
while (1) {
char msg[8192]; // CONSOLE_EXT_LOG_MAX.
- unsigned long long time_us;
- int facpri, subsystem, pos;
- char *p, *text;
ssize_t len;
// kmsg fails with EPIPE if we try to read while the buffer moves under
@@ -113,49 +171,14 @@ static void print_all(void)
if (len <= 0) break;
msg[len] = 0;
-
- if (sscanf(msg, "%u,%*u,%llu,%*[^;];%n", &facpri, &time_us, &pos) != 2)
- continue;
-
- // Drop extras after end of message text.
- text = msg + pos;
- if ((p = strchr(text, '\n'))) *p = 0;
-
- // Is there a subsystem? (The ": " is just a convention.)
- p = strstr(text, ": ");
- subsystem = p ? (p - text) : 0;
-
- // "Raw" is a lie for /dev/kmsg. In practice, it just means we show the
- // syslog facility/priority at the start of each line.
- if (toys.optflags&FLAG_r) printf("<%d>", facpri);
-
- if (!(toys.optflags&FLAG_t)) {
- color(32);
- printf("[%5lld.%06lld] ", time_us/1000000, time_us%1000000);
- color(0);
- }
-
- // Errors (or worse) are shown in red, subsystems are shown in yellow.
- if (subsystem) {
- color(33);
- printf("%.*s", subsystem, text);
- text += subsystem;
- color(0);
- }
- if (!((facpri&7) <= 3)) xputs(text);
- else {
- color(31);
- printf("%s", text);
- color(0);
- xputc('\n');
- }
+ format_message(msg, 1);
}
close(fd);
}
void dmesg_main(void)
{
- TT.color = isatty(1);
+ TT.use_color = isatty(1);
if (!(toys.optflags & (FLAG_C|FLAG_n))) print_all();