[PATCH v2 1/4] lib/vsprintf: Print time64_t in human readable format

From: Andy Shevchenko
Date: Tue Oct 01 2019 - 09:47:37 EST


There are users which print time and date represented by content of
time64_t type in human readable format.

Instead of open coding that each time introduce %ptT[dt][r] specifier.

Few test cases for %ptT specifier has been added as well.

Cc: Hans Verkuil <hverkuil@xxxxxxxxx>
Cc: Mathias Nyman <mathias.nyman@xxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
Cc: Jonathan Hunter <jonathanh@xxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
Documentation/core-api/printk-formats.rst | 22 ++++++++--------
lib/test_printf.c | 13 +++++++---
lib/vsprintf.c | 31 +++++++++++++++++++++--
3 files changed, 51 insertions(+), 15 deletions(-)

diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index ecbebf4ca8e7..83f452e45f3f 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -428,21 +428,23 @@ Examples::

Passed by reference.

-Time and date (struct rtc_time)
--------------------------------
+Time and date
+-------------

::

- %ptR YYYY-mm-ddTHH:MM:SS
- %ptRd YYYY-mm-dd
- %ptRt HH:MM:SS
- %ptR[dt][r]
+ %pt[RT] YYYY-mm-ddTHH:MM:SS
+ %pt[RT]d YYYY-mm-dd
+ %pt[RT]t HH:MM:SS
+ %pt[RT][dt][r]

-For printing date and time as represented by struct rtc_time structure in
-human readable format.
+For printing date and time as represented by
+ R struct rtc_time structure
+ T time64_t type
+in human readable format.

-By default year will be incremented by 1900 and month by 1. Use %ptRr (raw)
-to suppress this behaviour.
+By default year will be incremented by 1900 and month by 1.
+Use %pt[RT]r (raw) to suppress this behaviour.

Passed by reference.

diff --git a/lib/test_printf.c b/lib/test_printf.c
index 5d94cbff2120..16fb668685dd 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -476,7 +476,7 @@ struct_va_format(void)
}

static void __init
-struct_rtc_time(void)
+time_and_date(void)
{
/* 1543210543 */
const struct rtc_time tm = {
@@ -487,14 +487,21 @@ struct_rtc_time(void)
.tm_mon = 10,
.tm_year = 118,
};
+ /* 2019-01-04T15:32:23 */
+ time64_t t = 1546615943;

- test("(%ptR?)", "%pt", &tm);
+ test("(%pt?)", "%pt", &tm);
test("2018-11-26T05:35:43", "%ptR", &tm);
test("0118-10-26T05:35:43", "%ptRr", &tm);
test("05:35:43|2018-11-26", "%ptRt|%ptRd", &tm, &tm);
test("05:35:43|0118-10-26", "%ptRtr|%ptRdr", &tm, &tm);
test("05:35:43|2018-11-26", "%ptRttr|%ptRdtr", &tm, &tm);
test("05:35:43 tr|2018-11-26 tr", "%ptRt tr|%ptRd tr", &tm, &tm);
+
+ test("2019-01-04T15:32:23", "%ptT", &t);
+ test("0119-00-04T15:32:23", "%ptTr", &t);
+ test("15:32:23|2019-01-04", "%ptTt|%ptTd", &t, &t);
+ test("15:32:23|0119-00-04", "%ptTtr|%ptTdr", &t, &t);
}

static void __init
@@ -610,7 +617,7 @@ test_pointer(void)
uuid();
dentry();
struct_va_format();
- struct_rtc_time();
+ time_and_date();
struct_clk();
bitmap();
netdev_features();
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index e78017a3e1bd..e4bc380deb62 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -33,6 +33,7 @@
#include <linux/dcache.h>
#include <linux/cred.h>
#include <linux/rtc.h>
+#include <linux/time.h>
#include <linux/uuid.h>
#include <linux/of.h>
#include <net/addrconf.h>
@@ -1780,6 +1781,29 @@ char *rtc_str(char *buf, char *end, const struct rtc_time *tm,
return buf;
}

+static noinline_for_stack
+char *time64_str(char *buf, char *end, const time64_t time,
+ struct printf_spec spec, const char *fmt)
+{
+ struct rtc_time rtc_time;
+ struct tm tm;
+
+ time64_to_tm(time, 0, &tm);
+
+ rtc_time.tm_sec = tm.tm_sec;
+ rtc_time.tm_min = tm.tm_min;
+ rtc_time.tm_hour = tm.tm_hour;
+ rtc_time.tm_mday = tm.tm_mday;
+ rtc_time.tm_mon = tm.tm_mon;
+ rtc_time.tm_year = tm.tm_year;
+ rtc_time.tm_wday = tm.tm_wday;
+ rtc_time.tm_yday = tm.tm_yday;
+
+ rtc_time.tm_isdst = 0;
+
+ return rtc_str(buf, end, &rtc_time, spec, fmt);
+}
+
static noinline_for_stack
char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
const char *fmt)
@@ -1787,8 +1811,10 @@ char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
switch (fmt[1]) {
case 'R':
return rtc_str(buf, end, (const struct rtc_time *)ptr, spec, fmt);
+ case 'T':
+ return time64_str(buf, end, *(const time64_t *)ptr, spec, fmt);
default:
- return error_string(buf, end, "(%ptR?)", spec);
+ return error_string(buf, end, "(%pt?)", spec);
}
}

@@ -2088,8 +2114,9 @@ static char *kobject_string(char *buf, char *end, void *ptr,
* - 'd[234]' For a dentry name (optionally 2-4 last components)
* - 'D[234]' Same as 'd' but for a struct file
* - 'g' For block_device name (gendisk + partition number)
- * - 't[R][dt][r]' For time and date as represented:
+ * - 't[RT][dt][r]' For time and date as represented by:
* R struct rtc_time
+ * T time64_t
* - 'C' For a clock, it prints the name (Common Clock Framework) or address
* (legacy clock framework) of the clock
* - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
--
2.23.0