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Date: Tue, 20 Nov 2018 23:27:57 +0100
From: Alexandre Belloni <alexandre.belloni@...tlin.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Rasmus Villemoes <rasmus.villemoes@...vas.dk>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-kernel@...r.kernel.org,
Alessandro Zummo <a.zummo@...ertech.it>,
linux-rtc@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
Joe Perches <joe@...ches.com>,
Mark Salyzyn <salyzyn@...roid.com>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Guan Xuetao <gxt@...c.pku.edu.cn>,
Ingo Molnar <mingo@...nel.org>,
Jason Wessel <jason.wessel@...driver.com>,
Jonathan Corbet <corbet@....net>,
Jonathan Hunter <jonathanh@...dia.com>,
Krzysztof Kozlowski <krzk@...nel.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Thierry Reding <thierry.reding@...il.com>
Subject: Re: [PATCH v3 01/20] lib/vsprintf: Print time and date in human
readable format via %pt
Hello,
(Please update my email address).
On 13/11/2018 19:17:10+0200, Andy Shevchenko wrote:
> There are users which print time and date represented by content of
> struct rtc_time in human readable format.
>
> Instead of open coding that each time introduce %ptR[dt][rv] specifier.
>
> Note, users have to select PRINTK_PEXT_TIMEDATE option in a Kconfig.
>
> Cc: Arnd Bergmann <arnd@...db.de>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>
> Cc: Geert Uytterhoeven <geert@...ux-m68k.org>
> Cc: Guan Xuetao <gxt@...c.pku.edu.cn>
> Cc: Ingo Molnar <mingo@...nel.org>
> Cc: Jason Wessel <jason.wessel@...driver.com>
> Cc: Jonathan Corbet <corbet@....net>
> Cc: Jonathan Hunter <jonathanh@...dia.com>
> Cc: Krzysztof Kozlowski <krzk@...nel.org>
> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> Cc: Thierry Reding <thierry.reding@...il.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
> Documentation/core-api/printk-formats.rst | 20 ++++
> lib/test_printf.c | 6 +
> lib/vsprintf.c | 140 ++++++++++++++++++++++
> 3 files changed, 166 insertions(+)
>
> diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
> index ff48b55040ef..8342a65eab0b 100644
> --- a/Documentation/core-api/printk-formats.rst
> +++ b/Documentation/core-api/printk-formats.rst
> @@ -412,6 +412,26 @@ Examples::
>
> Passed by reference.
>
> +Time and date (struct rtc_time)
> +-------------------------------
> +
> +::
> +
> + %ptR YYYY-mm-dd HH:MM:SS
> + %ptRd YYYY-mm-dd
> + %ptRt HH:MM:SS
> + %ptR[dt][rv]
> +
> +For printing date and time as represented by struct rtc_time structure in
> +human readable format.
> +
> +By default year will be incremented by 1900 and month by 1. Use %ptRr (raw)
> +to suppress this behaviour. On the other hand when %ptRv is applied
> +validation mechanism will be in use, i.e. numbers out of range will be
> +replaced by ** or ****.
> +
> +Passed by reference.
> +
> struct clk
> ----------
>
> diff --git a/lib/test_printf.c b/lib/test_printf.c
> index 53527ea822b5..97b7d14961d6 100644
> --- a/lib/test_printf.c
> +++ b/lib/test_printf.c
> @@ -418,6 +418,11 @@ struct_va_format(void)
> {
> }
>
> +static void __init
> +struct_rtc_time(void)
> +{
> +}
> +
> static void __init
> struct_clk(void)
> {
> @@ -529,6 +534,7 @@ test_pointer(void)
> uuid();
> dentry();
> struct_va_format();
> + struct_rtc_time();
> struct_clk();
> bitmap();
> netdev_features();
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 37a54a6dd594..8455cbda8d6c 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -30,6 +30,7 @@
> #include <linux/ioport.h>
> #include <linux/dcache.h>
> #include <linux/cred.h>
> +#include <linux/rtc.h>
> #include <linux/uuid.h>
> #include <linux/of.h>
> #include <net/addrconf.h>
> @@ -822,6 +823,20 @@ static const struct printf_spec default_dec_spec = {
> .precision = -1,
> };
>
> +static const struct printf_spec default_dec02_spec = {
> + .base = 10,
> + .field_width = 2,
> + .precision = -1,
> + .flags = ZEROPAD,
> +};
> +
> +static const struct printf_spec default_dec04_spec = {
> + .base = 10,
> + .field_width = 4,
> + .precision = -1,
> + .flags = ZEROPAD,
> +};
> +
> static noinline_for_stack
> char *resource_string(char *buf, char *end, struct resource *res,
> struct printf_spec spec, const char *fmt)
> @@ -1549,6 +1564,127 @@ char *address_val(char *buf, char *end, const void *addr, const char *fmt)
> return special_hex_number(buf, end, num, size);
> }
>
> +static noinline_for_stack
> +char *date_str(char *buf, char *end, const struct rtc_time *tm, bool v, bool r)
> +{
> + int year = tm->tm_year + (r ? 0 : 1900);
> + int mon = tm->tm_mon + (r ? 0 : 1);
> +
> + if (unlikely(v && (unsigned int)tm->tm_year > 200))
> + buf = string(buf, end, "****", default_str_spec);
I think you should drop the validation option. This is only used in a
deprecated ABI and is mostly wrong as many RTCs will still be valid
after 2100.
> + else
> + buf = number(buf, end, year, default_dec04_spec);
> +
> + if (buf < end)
> + *buf = '-';
> + buf++;
> +
> + if (unlikely(v && (unsigned int)tm->tm_mon > 11))
> + buf = string(buf, end, "**", default_str_spec);
> + else
> + buf = number(buf, end, mon, default_dec02_spec);
> +
> + if (buf < end)
> + *buf = '-';
> + buf++;
> +
> + if (unlikely(v && (unsigned int)tm->tm_mday > 31))
> + buf = string(buf, end, "**", default_str_spec);
Same here, this doesn't protect February, April, June, September and
November. There is one RTC that think that 31st of November is valid.
> + else
> + buf = number(buf, end, tm->tm_mday, default_dec02_spec);
> +
> + return buf;
> +}
> +
> +static noinline_for_stack
> +char *time_str(char *buf, char *end, const struct rtc_time *tm, bool v, bool r)
> +{
> + if (unlikely(v && (unsigned int)tm->tm_hour > 24))
> + buf = string(buf, end, "**", default_str_spec);
> + else
> + buf = number(buf, end, tm->tm_hour, default_dec02_spec);
> +
> + if (buf < end)
> + *buf = ':';
> + buf++;
> +
> + if (unlikely(v && (unsigned int)tm->tm_min > 59))
> + buf = string(buf, end, "**", default_str_spec);
> + else
> + buf = number(buf, end, tm->tm_min, default_dec02_spec);
> +
> + if (buf < end)
> + *buf = ':';
> + buf++;
> +
> + if (unlikely(v && (unsigned int)tm->tm_sec > 59))
> + buf = string(buf, end, "**", default_str_spec);
Some RTCs will consider 60 valid. So, really, instead of fixing all of
those, I'd just get rid of the validation option.
> + else
> + buf = number(buf, end, tm->tm_sec, default_dec02_spec);
> +
> + return buf;
> +}
> +
> +static noinline_for_stack
> +char *rtc_str(char *buf, char *end, const struct rtc_time *tm, const char *fmt)
> +{
> + bool have_t = true, have_d = true;
> + bool validate = false;
> + bool raw = false;
> + int count = 2;
> + bool found;
> +
> + switch (fmt[count]) {
> + case 'd':
> + have_t = false;
> + count++;
> + break;
> + case 't':
> + have_d = false;
> + count++;
> + break;
> + }
> +
> + found = true;
> + do {
> + switch (fmt[count++]) {
> + case 'r':
> + raw = true;
> + break;
> + case 'v':
> + validate = true;
> + break;
> + default:
> + found = false;
> + break;
> + }
> + } while (found);
> +
> + if (have_d)
> + buf = date_str(buf, end, tm, validate, raw);
> + if (have_d && have_t) {
> + if (buf < end)
> + *buf = ' ';
I'd go for ISO 8601 and use a 'T' here.
> + buf++;
> + }
> + if (have_t)
> + buf = time_str(buf, end, tm, validate, raw);
> +
> + return buf;
> +}
> +
> +static noinline_for_stack
> +char *timeanddate(char *buf, char *end, void *ptr, struct printf_spec spec,
> + const char *fmt)
> +{
> + switch (fmt[1]) {
> + case 'R':
> + return rtc_str(buf, end, (const struct rtc_time *)ptr, fmt);
> + default:
> + return ptr_to_id(buf, end, ptr, spec);
> + }
> +}
> +
> static noinline_for_stack
> char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
> const char *fmt)
> @@ -1828,6 +1964,8 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
> * - '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][rv]' For time and date as represented:
> + * R struct rtc_time
> * - '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
> @@ -1952,6 +2090,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
> return address_val(buf, end, ptr, fmt);
> case 'd':
> return dentry_name(buf, end, ptr, spec, fmt);
> + case 't':
> + return timeanddate(buf, end, ptr, spec, fmt);
> case 'C':
> return clock(buf, end, ptr, spec, fmt);
> case 'D':
> --
> 2.19.1
>
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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