| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Thu, 17 May 2012 17:02:49 +0200
From: Sasha Levin <levinsasha928@...il.com>
To: greg@...ah.com, kay@...y.org, torvalds@...ux-foundation.org
Cc: mingo@...nel.org, linux-kernel@...r.kernel.org, joe@...ches.com,
hpa@...nel.org, yinghai@...nel.org,
Sasha Levin <levinsasha928@...il.com>
Subject: [RFC] printk: add relative printk timing support
This patch adds support for relative timestamps in printk output.
First, this is how it looks now:
[ 120.001386] foo
[ 181.036862] bar
[ 186.070696] zoot
[ 196.288022] foo
[ 257.415895] bar
[ 257.416580] zoot
Next, with Linus' suggestion (Month and date, no seconds):
[May 17 14:13] foo
[May 17 14:14] bar
[+05.00026906] zoot
[+10.00054898] foo
[May 17 14:15] bar
[+00.00000668] zoot
And Peter's suggestion (MS accurate absolute time):
[14:16:57.970] foo
[14:17:59.063] bar
[+05.00032139] zoot
[+10.00336079] foo
[14:19:15.677] bar
[+00.00001905] zoot
Todo:
- Can we get rid of the spinlock somehow? I tried using atomic64_t, but got
hit with races causing odd prints.
- Do we want to make the 60 second "timeout" for printing abs time
configurable?
- Are there any other formats we would want to add?
Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <levinsasha928@...il.com>
---
kernel/printk.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 44 insertions(+), 6 deletions(-)
diff --git a/kernel/printk.c b/kernel/printk.c
index 32462d2..9d008e5 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -779,11 +779,12 @@ static int check_syslog_permissions(int type, bool from_file)
}
#if defined(CONFIG_PRINTK_TIME)
-static bool printk_time = 1;
+static int printk_time = 1;
#else
-static bool printk_time;
+static int printk_time;
#endif
-module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
+module_param_named(time, printk_time, int, S_IRUGO | S_IWUSR);
+static DEFINE_SPINLOCK(printk_time_rel);
static size_t print_prefix(const struct log *msg, bool syslog, char *buf)
{
@@ -801,16 +802,53 @@ static size_t print_prefix(const struct log *msg, bool syslog, char *buf)
}
}
- if (printk_time) {
+ if (printk_time == 1) {
if (buf) {
unsigned long long ts = msg->ts_nsec;
- unsigned long rem_nsec = do_div(ts, 1000000000);
+ unsigned long rem_nsec = do_div(ts, NSEC_PER_SEC);
len += sprintf(buf + len, "[%5lu.%06lu] ",
- (unsigned long) ts, rem_nsec / 1000);
+ (unsigned long) ts, rem_nsec / NSEC_PER_USEC);
} else {
len += 15;
}
+ } else if (printk_time == 2 || printk_time == 3) {
+ static unsigned long long last_print;
+ unsigned long long ts = msg->ts_nsec;
+ unsigned long rem_nsec;
+ bool rel = 0;
+ static const char *months[12] = {"Jan", "Feb", "Mar", "Apr",
+ "May", "Jun", "Jul", "Aug",
+ "Sep", "Oct", "Nov", "Dec",};
+
+ if (!buf)
+ return len + 15;
+
+ spin_lock(&printk_time_rel);
+ if ((ts - last_print) / NSEC_PER_SEC < 60) {
+ rel = 1;
+ ts -= last_print;
+ }
+ last_print = msg->ts_nsec;
+ spin_unlock(&printk_time_rel);
+
+ rem_nsec = do_div(ts, NSEC_PER_SEC);
+ if (rel) {
+ len += sprintf(buf + len, "[%+03d.%08lu] ",
+ (int)ts, rem_nsec / NSEC_PER_USEC);
+ } else {
+ struct tm tm;
+
+ time_to_tm(get_seconds(), 0, &tm);
+ if (printk_time == 2)
+ len += sprintf(buf + len, "[%s %02d %02d:%02d] ",
+ months[tm.tm_mon], tm.tm_mday,
+ tm.tm_hour, tm.tm_min);
+ if (printk_time == 3)
+ len += sprintf(buf + len, "[%02d:%02d:%02d.%03lu] ",
+ tm.tm_hour, tm.tm_min, tm.tm_sec,
+ rem_nsec / NSEC_PER_MSEC);
+ }
}
return len;
--
1.7.8.6
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists