On Tue, 12 Jul 2016, Ruediger Meier wrote: > On Tuesday 12 July 2016, Sami Kerola wrote: > > On 12 July 2016 at 15:23, Ruediger Meier <sweet_f_a@xxxxxx> wrote: > > > On Tuesday 12 July 2016, Sami Kerola wrote: > > >> On 11 July 2016 at 21:23, J William Piggott <elseifthen@xxxxxxx> > > > > > > wrote: > > >> > We use mktime(3) for portability. > > >> > > > >> > http://www.gnu.org/software/libc/manual/html_mono/libc.html#inde > > >> >x-t imegm > > >> > > > >> > Portability note: mktime is essentially universally available. > > >> > timegm is rather rare. For the most portable conversion from a > > >> > UTC broken-down time to a simple time, set the TZ environment > > >> > variable to UTC, call mktime, then set TZ back. > > >> > > >> I don't think hwclock(8) is portable. It has ioctl(2) calls, and > > >> such. > > > > > > But there are non-gnu libc's for Linux. > > > > Fair point, but can you name one that does not have timegm(). > > > > https://github.com/cloudius-systems/musl/blob/master/src/time/timegm. > >c https://github.com/ensc/dietlibc/blob/master/libugly/timegm.c > > http://www.uclibc-ng.org/browser/uclibc-ng/libc/misc/time/timegm.c?or > >der=name > > > Yep, also musl has timegm. But at least it's good that William reminded > us to check that! :) Oh well. I guess it does not hurt to support incomplete libraries even if we might not be able to name them. https://github.com/kerolasa/lelux-utiliteetit/commit/5dff764bb38f0745a8bb128337d2534f109a37c8 and the same as email body so that review is possible. --->8---- From: Sami Kerola <kerolasa@xxxxxx> Date: Tue, 12 Jul 2016 22:21:10 +0100 Subject: [PATCH] lib: add portability functions, start with timegm() The lib/portability.c is a file where functions that may be missing from libraries can be added. CC: Ruediger Meier <ruediger.meier@xxxxxxxxxxx> CC: J William Piggott <elseifthen@xxxxxxx> Signed-off-by: Sami Kerola <kerolasa@xxxxxx> --- configure.ac | 1 + include/Makemodule.am | 1 + include/portability.h | 8 ++++++++ lib/Makemodule.am | 1 + lib/portability.c | 28 ++++++++++++++++++++++++++++ login-utils/utmpdump.c | 1 + sys-utils/hwclock.c | 1 + 7 files changed, 41 insertions(+) create mode 100644 include/portability.h create mode 100644 lib/portability.c diff --git a/configure.ac b/configure.ac index 39d9aca..0835838 100644 --- a/configure.ac +++ b/configure.ac @@ -413,6 +413,7 @@ AC_CHECK_FUNCS([ \ strnlen \ sysconf \ sysinfo \ + timegm \ updwtmp \ usleep \ warn \ diff --git a/include/Makemodule.am b/include/Makemodule.am index 5ceff0a..9eff5c8 100644 --- a/include/Makemodule.am +++ b/include/Makemodule.am @@ -35,6 +35,7 @@ dist_noinst_HEADERS += \ include/path.h \ include/pathnames.h \ include/plymouth-ctrl.h \ + include/portability.h \ include/procutils.h \ include/pt-bsd.h \ include/pt-mbr.h \ diff --git a/include/portability.h b/include/portability.h new file mode 100644 index 0000000..2a60ede --- /dev/null +++ b/include/portability.h @@ -0,0 +1,8 @@ +#ifndef UTIL_LINUX_PORTABILITY_H +#define UTIL_LINUX_PORTABILITY_H + +#ifndef HAVE_TIMEGM +extern time_t timegm(struct tm *tm); +#endif + +#endif /* UTIL_LINUX_PORTABILITY_H */ diff --git a/lib/Makemodule.am b/lib/Makemodule.am index 704a16e..57b1d86 100644 --- a/lib/Makemodule.am +++ b/lib/Makemodule.am @@ -16,6 +16,7 @@ libcommon_la_SOURCES = \ lib/md5.c \ lib/pager.c \ lib/path.c \ + lib/portability.c \ lib/randutils.c \ lib/setproctitle.c \ lib/strutils.c \ diff --git a/lib/portability.c b/lib/portability.c new file mode 100644 index 0000000..cbc49a5 --- /dev/null +++ b/lib/portability.c @@ -0,0 +1,28 @@ +/* + * Functions in this file are replacements when library functions neither + * unimplemented or unavailable due old version. In best case these + * functions are never needed. + */ + +#include <time.h> +#include <stdlib.h> + +#include "portability.h" + +#ifndef HAVE_TIMEGM +time_t timegm(struct tm *tm) +{ + const char *zone = getenv("TZ"); + time_t ret; + + setenv("TZ", "", 1); + tzset(); + ret = mktime(tm); + if (zone) + setenv("TZ", zone, 1); + else + unsetenv("TZ"); + tzset(); + return ret; +} +#endif /* HAVE_TIMEGM */ diff --git a/login-utils/utmpdump.c b/login-utils/utmpdump.c index 1849a4e..43fc842 100644 --- a/login-utils/utmpdump.c +++ b/login-utils/utmpdump.c @@ -45,6 +45,7 @@ #include "timeutils.h" #include "xalloc.h" #include "closestream.h" +#include "portability.h" static time_t strtotime(const char *s_time) { diff --git a/sys-utils/hwclock.c b/sys-utils/hwclock.c index bcaab8b..fb9d628 100644 --- a/sys-utils/hwclock.c +++ b/sys-utils/hwclock.c @@ -78,6 +78,7 @@ #include "nls.h" #include "optutils.h" #include "pathnames.h" +#include "portability.h" #include "strutils.h" #include "hwclock.h" #include "timeutils.h" -- 2.9.0 -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
