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    SubjectRe: [PATCH v3 01/20] lib/vsprintf: Print time and date in human readable format via %pt
    On Tue, Nov 20, 2018 at 11:27:57PM +0100, Alexandre Belloni wrote:
    > Hello,
    >
    > (Please update my email address).

    I will follow all recommendations.
    New version coming soon...

    Thanks for review!

    >
    > 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@arndb.de>
    > > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
    > > Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
    > > Cc: Geert Uytterhoeven <geert@linux-m68k.org>
    > > Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
    > > Cc: Ingo Molnar <mingo@kernel.org>
    > > Cc: Jason Wessel <jason.wessel@windriver.com>
    > > Cc: Jonathan Corbet <corbet@lwn.net>
    > > Cc: Jonathan Hunter <jonathanh@nvidia.com>
    > > Cc: Krzysztof Kozlowski <krzk@kernel.org>
    > > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
    > > Cc: Thierry Reding <thierry.reding@gmail.com>
    > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.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

    --
    With Best Regards,
    Andy Shevchenko


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