[PATCH] timezone: Remove TZNAME_MAX limit from sysconf [BZ #15576]
Adhemerval Zanella
adhemerval.zanella@linaro.org
Tue Mar 7 10:55:00 GMT 2017
LGTM.
On 07/03/2017 10:13, Florian Weimer wrote:
> glibc does not impose a limit, and POSIX does not allow a
> sysconf limit which changes during the lifetime of a process.
>
> 2017-03-07 Florian Weimer <fweimer@redhat.com>
>
> [BZ #15576]
> Remove TZNAME_MAX limit from sysconf.
> * include/time.h (__tzname_cur_max, __tzname_max): Remove
> declaration.
> * time/tzfile.c (__tzfile_read, __tzfile_default): Do not call
> compute_tzname_max.
> (compute_tzname_max): Remove.
> * time/tzset.c (__tzname_cur_max, __tzname_max): Remove.
> (update_vars): Do not update __tzname_cur_max.
> (tzset_internal): Remove argument.
> (__tzset): Adjust call to tzset_internal.
> (__tz_convert): Likewise.
> * posix/sysconf.c (__sysconf): Return -1 for _SC_TZNAME_MAX.
> * sysdeps/posix/sysconf.c (__sysconf): Likewise.
> * manual/conf.texi (Sysconf Definition): Update comment.
>
> diff --git a/include/time.h b/include/time.h
> index 684ceb8..6badf0e 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -37,10 +37,6 @@ extern struct tm _tmbuf attribute_hidden;
> /* Defined in tzset.c. */
> extern char *__tzstring (const char *string);
>
> -/* Defined in tzset.c. */
> -extern size_t __tzname_cur_max attribute_hidden;
> -
> -
> extern int __use_tzfile attribute_hidden;
>
> extern void __tzfile_read (const char *file, size_t extra,
> @@ -82,10 +78,6 @@ extern void __tzset (void);
> /* Prototype for the internal function to get information based on TZ. */
> extern struct tm *__tz_convert (const time_t *timer, int use_localtime, struct tm *tp);
>
> -/* Return the maximum length of a timezone name.
> - This is what `sysconf (_SC_TZNAME_MAX)' does. */
> -extern long int __tzname_max (void);
> -
> extern int __nanosleep (const struct timespec *__requested_time,
> struct timespec *__remaining);
> libc_hidden_proto (__nanosleep)
> diff --git a/manual/conf.texi b/manual/conf.texi
> index 78b7a4d..1fe75c2 100644
> --- a/manual/conf.texi
> +++ b/manual/conf.texi
> @@ -291,14 +291,10 @@ constants are declared in the header file @file{unistd.h}.
> @safety{@prelim{}@mtsafe{@mtsenv{}}@asunsafe{@asulock{} @ascuheap{}}@acunsafe{@aculock{} @acsmem{} @acsfd{}}}
> @c Some parts of the implementation open /proc and /sys files and dirs
> @c to collect system details, using fd and stream I/O depending on the
> -@c case. _SC_TZNAME_MAX calls __tzname_max, that (while holding a lock)
> -@c calls tzset_internal, that calls getenv if it's called the first
> -@c time; there are free and strdup calls in there too. The returned max
> -@c value may change over time for TZNAME_MAX, depending on selected
> -@c timezones; NPROCS, NPROCS_CONF, PHYS_PAGES, AVPHYS_PAGES,
> -@c NGROUPS_MAX, SIGQUEUE_MAX, depending on variable values read from
> -@c /proc at each call, and from rlimit-obtained values CHILD_MAX,
> -@c OPEN_MAX, ARG_MAX, SIGQUEUE_MAX.
> +@c case. The returned max value may change over time for NPROCS,
> +@c NPROCS_CONF, PHYS_PAGES, AVPHYS_PAGES, NGROUPS_MAX, SIGQUEUE_MAX,
> +@c depending on variable values read from /proc at each call, and from
> +@c rlimit-obtained values CHILD_MAX, OPEN_MAX, ARG_MAX, SIGQUEUE_MAX.
> This function is used to inquire about runtime system parameters. The
> @var{parameter} argument should be one of the @samp{_SC_} symbols listed
> below.
> diff --git a/posix/sysconf.c b/posix/sysconf.c
> index 0b73b6a..4e9ed97 100644
> --- a/posix/sysconf.c
> +++ b/posix/sysconf.c
> @@ -37,7 +37,7 @@ __sysconf (int name)
> return -1;
>
> case _SC_TZNAME_MAX:
> - return MAX (__tzname_max (), _POSIX_TZNAME_MAX);
> + return -1;
>
> case _SC_CHARCLASS_NAME_MAX:
> #ifdef CHARCLASS_NAME_MAX
> diff --git a/sysdeps/posix/sysconf.c b/sysdeps/posix/sysconf.c
> index 19ed5b0..a95e1b3 100644
> --- a/sysdeps/posix/sysconf.c
> +++ b/sysdeps/posix/sysconf.c
> @@ -93,7 +93,7 @@ __sysconf (int name)
> #endif
>
> case _SC_TZNAME_MAX:
> - return MAX (__tzname_max (), _POSIX_TZNAME_MAX);
> + return -1;
>
> case _SC_JOB_CONTROL:
> #if CONF_IS_DEFINED_SET (_POSIX_JOB_CONTROL)
> diff --git a/time/tzfile.c b/time/tzfile.c
> index 4987f1a..d412469 100644
> --- a/time/tzfile.c
> +++ b/time/tzfile.c
> @@ -48,8 +48,6 @@ struct leap
> long int change; /* Seconds of correction to apply. */
> };
>
> -static void compute_tzname_max (size_t) internal_function;
> -
> static size_t num_transitions;
> libc_freeres_ptr (static time_t *transitions);
> static unsigned char *type_idxs;
> @@ -494,8 +492,6 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
> if (__tzname[1] == NULL)
> __tzname[1] = __tzname[0];
>
> - compute_tzname_max (chars);
> -
> if (num_transitions == 0)
> /* Use the first rule (which should also be the only one). */
> rule_stdoff = rule_dstoff = types[0].offset;
> @@ -626,8 +622,6 @@ __tzfile_default (const char *std, const char *dst,
> /* Set the timezone. */
> __timezone = -types[0].offset;
>
> - compute_tzname_max (stdlen + dstlen);
> -
> /* Invalidate the tzfile attribute cache to force rereading
> TZDEFRULES the next time it is used. */
> tzfile_dev = 0;
> @@ -836,21 +830,3 @@ __tzfile_compute (time_t timer, int use_localtime,
> }
> }
> }
> -
> -static void
> -internal_function
> -compute_tzname_max (size_t chars)
> -{
> - const char *p;
> -
> - p = zone_names;
> - do
> - {
> - const char *start = p;
> - while (*p != '\0')
> - ++p;
> - if ((size_t) (p - start) > __tzname_cur_max)
> - __tzname_cur_max = p - start;
> - }
> - while (++p < &zone_names[chars]);
> -}
> diff --git a/time/tzset.c b/time/tzset.c
> index 262bbe5..f0e5c95 100644
> --- a/time/tzset.c
> +++ b/time/tzset.c
> @@ -68,8 +68,7 @@ static tz_rule tz_rules[2];
>
>
> static void compute_change (tz_rule *rule, int year) __THROW internal_function;
> -static void tzset_internal (int always, int explicit)
> - __THROW internal_function;
> +static void tzset_internal (int always);
>
> /* List of buffers containing time zone strings. */
> struct tzstring_l
> @@ -126,24 +125,7 @@ __tzstring (const char *s)
> {
> return __tzstring_len (s, strlen (s));
> }
> -
> -/* Maximum length of a timezone name. tzset_internal keeps this up to date
> - (never decreasing it) when ! __use_tzfile.
> - tzfile.c keeps it up to date when __use_tzfile. */
> -size_t __tzname_cur_max;
>
> -long int
> -__tzname_max (void)
> -{
> - __libc_lock_lock (tzset_lock);
> -
> - tzset_internal (0, 0);
> -
> - __libc_lock_unlock (tzset_lock);
> -
> - return __tzname_cur_max;
> -}
> -
> static char *old_tz;
>
> static void
> @@ -154,14 +136,6 @@ update_vars (void)
> __timezone = -tz_rules[0].offset;
> __tzname[0] = (char *) tz_rules[0].name;
> __tzname[1] = (char *) tz_rules[1].name;
> -
> - /* Keep __tzname_cur_max up to date. */
> - size_t len0 = strlen (__tzname[0]);
> - size_t len1 = strlen (__tzname[1]);
> - if (len0 > __tzname_cur_max)
> - __tzname_cur_max = len0;
> - if (len1 > __tzname_cur_max)
> - __tzname_cur_max = len1;
> }
>
>
> @@ -390,8 +364,7 @@ __tzset_parse_tz (const char *tz)
>
> /* Interpret the TZ envariable. */
> static void
> -internal_function
> -tzset_internal (int always, int explicit)
> +tzset_internal (int always)
> {
> static int is_initialized;
> const char *tz;
> @@ -402,12 +375,6 @@ tzset_internal (int always, int explicit)
>
> /* Examine the TZ environment variable. */
> tz = getenv ("TZ");
> - if (tz == NULL && !explicit)
> - /* Use the site-wide default. This is a file name which means we
> - would not see changes to the file if we compare only the file
> - name for change. We want to notice file changes if tzset() has
> - been called explicitly. Leave TZ as NULL in this case. */
> - tz = TZDEFAULT;
> if (tz && *tz == '\0')
> /* User specified the empty string; use UTC explicitly. */
> tz = "Universal";
> @@ -583,7 +550,7 @@ __tzset (void)
> {
> __libc_lock_lock (tzset_lock);
>
> - tzset_internal (1, 1);
> + tzset_internal (1);
>
> if (!__use_tzfile)
> {
> @@ -615,7 +582,7 @@ __tz_convert (const time_t *timer, int use_localtime, struct tm *tp)
> /* Update internal database according to current TZ setting.
> POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname.
> This is a good idea since this allows at least a bit more parallelism. */
> - tzset_internal (tp == &_tmbuf && use_localtime, 1);
> + tzset_internal (tp == &_tmbuf && use_localtime);
>
> if (__use_tzfile)
> __tzfile_compute (*timer, use_localtime, &leap_correction,
>
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