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 --- toys/pending/dmesg.c | 153 +++++++++++++++++++++++++++++---------------------- 1 file changed, 88 insertions(+), 65 deletions(-)
From 82e4585c6841a990cb0389324923d9a7d725de17 Mon Sep 17 00:00:00 2001 From: Elliott Hughes <e...@google.com> Date: Sat, 25 Mar 2017 13:08:20 -0700 Subject: [PATCH] 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 --- toys/pending/dmesg.c | 153 +++++++++++++++++++++++++++++---------------------- 1 file changed, 88 insertions(+), 65 deletions(-) diff --git a/toys/pending/dmesg.c b/toys/pending/dmesg.c index 40834b0..198f64a 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(); -- 2.12.1.578.ge9c3154ca4-goog
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