From 9ef3a9f8b2704693496af12120ea3ab40389bf7b Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Mon, 24 Oct 2016 02:15:36 +0000 Subject: Add the alarm library, first draft. --- configure | 29 +++++++----- doc/libstddjb/alarm.html | 94 ++++++++++++++++++++++++++++++++++++++ doc/libstddjb/index.html | 1 + package/deps.mak | 7 ++- src/include/skalibs/alarm.h | 13 ++++++ src/include/skalibs/stddjb.h | 1 + src/libstddjb/alarm-internal.h | 14 ++++++ src/libstddjb/alarm_deadline.c | 47 +++++++++++++++++++ src/libstddjb/alarm_disable.c | 41 +++++++++++++++++ src/libstddjb/alarm_milliseconds.c | 61 +++++++++++++++++++++++++ src/libstddjb/alarm_timeout.c | 65 ++++++++++++++++++++++++++ src/libstddjb/alloc-internal.h | 4 +- src/sysdeps/tryitimer.c | 10 ++++ src/sysdeps/trytimer.c | 12 +++++ 14 files changed, 385 insertions(+), 14 deletions(-) create mode 100644 doc/libstddjb/alarm.html create mode 100644 src/include/skalibs/alarm.h create mode 100644 src/libstddjb/alarm-internal.h create mode 100644 src/libstddjb/alarm_deadline.c create mode 100644 src/libstddjb/alarm_disable.c create mode 100644 src/libstddjb/alarm_milliseconds.c create mode 100644 src/libstddjb/alarm_timeout.c create mode 100644 src/sysdeps/tryitimer.c create mode 100644 src/sysdeps/trytimer.c diff --git a/configure b/configure index 96699f6..bb100ed 100755 --- a/configure +++ b/configure @@ -118,19 +118,24 @@ tryldflag () { } choose () { + what="$1" + name="$2" + macro="$3" echo "Checking whether system has $4..." + shift 4 + libs="$*" r=true - case "$1" in - *c*) $CC_AUTO $CPPFLAGS_AUTO $CFLAGS_AUTO -o try$2.o -c src/sysdeps/try$2.c 2>/dev/null || r=false ;; + case "$what" in + *c*) $CC_AUTO $CPPFLAGS_AUTO $CFLAGS_AUTO -o try$name.o -c src/sysdeps/try$name.c 2>/dev/null || r=false ;; esac if $r ; then - case "$1" in - *l*) $CC_AUTO $CFLAGS_AUTO $LDFLAGS_AUTO -o try$2 try$2.o $5 2>/dev/null || r=false ;; + case "$what" in + *l*) $CC_AUTO $CFLAGS_AUTO $LDFLAGS_AUTO -o try$name try$name.o $libs 2>/dev/null || r=false ;; esac fi if $r ; then - case "$1" in - *r*) ./try$2 >/dev/null 2>&1 ; r=$? + case "$what" in + *r*) ./try$name >/dev/null 2>&1 ; r=$? case "$r" in 111) echo " ... test crashed, aborting." ; exit 111 ;; 0) r=true ;; @@ -138,14 +143,14 @@ choose () { esac esac fi - rm -f try$2.o try$2 + rm -f try$name.o try$name if $r ; then - echo "$2: yes" >> $sysdeps/sysdeps - echo "#define ${package_macro_name}_HAS$3" >> $sysdeps/sysdeps.h + echo "$name: yes" >> $sysdeps/sysdeps + echo "#define ${package_macro_name}_HAS$macro" >> $sysdeps/sysdeps.h echo " ... yes" else - echo "$2: no" >> $sysdeps/sysdeps - echo "#undef ${package_macro_name}_HAS$3" >> $sysdeps/sysdeps.h + echo "$name: no" >> $sysdeps/sysdeps + echo "#undef ${package_macro_name}_HAS$macro" >> $sysdeps/sysdeps.h echo " ... no" fi } @@ -490,6 +495,8 @@ EOF choose cl futimes FUTIMES 'futimes()' choose cl arc4random ARC4RANDOM 'arc4random()' choose cl getrandom GETRANDOM 'getrandom()' + choose cl timer TIMER 'timer_create()' $sysclock_lib + choose cl itimer ITIMER 'setitimer()' echo '#endif' >> $sysdeps/sysdeps.h fi diff --git a/doc/libstddjb/alarm.html b/doc/libstddjb/alarm.html new file mode 100644 index 0000000..da14267 --- /dev/null +++ b/doc/libstddjb/alarm.html @@ -0,0 +1,94 @@ + + + + + + skalibs: the alarm library interface + + + + + + +

+libstddjb
+libskarnet
+skalibs
+Software
+skarnet.org +

+ +

The `alarm` library interface

+ +

+ The following functions are declared in the skalibs/alarm.h header, +and implemented in the libskarnet.a or libskarnet.so library. +

+ +

General information

+ +

+ alarm is a set of primitives to provide the same functionality as +alarm(), +but with sub-second precision. +

+ +

+ Depending on the functionality the underlying system provides, +the precision can be 1 nanosecond (implementation via +timer_settime(), +1 microsecond (implementation via +setitimer(), +or 1 second (fallback implementation with +alarm() +when nothing better can be found). +

+ +

Functions

+ +

+ int alarm_milliseconds (unsigned int n)
+Sets a fuse that will raise a SIGALRM after n milliseconds. +If n is 0, the SIGALRM will be raised instantly. +Returns 1 on success and 0 (and sets errno) on failure. +

+ +

+ int alarm_timeout (tain_t const *tto)
+Sets a fuse that will raise a SIGALRM after some amount +of time has passed. The amount of time is described in +*tto, which is a relative +tain_t, i.e. a structure containing +a relative TAIN64 time. +Returns 1 on success and 0 (and sets errno) on failure. +

+ +

+ int alarm_deadline (tain_t const *deadline)
+Sets a fuse that will raise a SIGALRM when the clock reaches +*deadline, which is an absolute time expressed in +TAI64N format. +Returns 1 on success and 0 (and sets errno) on failure. +

+ +

+ void alarm_disable (void)
+Cancels a previously set fuse. No SIGALRM will be raised. +

+ +

Notes

+ +

Asynchronous programming via signals is bad. The best way +to handle situations where something happens after some time has +elapsed is to use an asynchronous loop primitive such as +iopause(). The problem is that some +external libraries only provide synchronous functions (including +functions talking to the network!) with no obvious way to set a +timeout. The alarm_* set of functions is meant to work +around that, with hopefully better granularity than the POSIX +alarm() function.

+ + + diff --git a/doc/libstddjb/index.html b/doc/libstddjb/index.html index dfa6f94..6ecfeb2 100644 --- a/doc/libstddjb/index.html +++ b/doc/libstddjb/index.html @@ -45,6 +45,7 @@ including them directly.

Programming

skalibs/alarm.h: sub-second precision alarm()
skalibs/alloc.h: basic heap memory allocation primitives
skalibs/allreadwrite.h: safe wrappers around I/O functions, extra I/O functions

+ +extern int alarm_milliseconds (unsigned int) ; +extern int alarm_timeout (tain_t const *) ; +extern int alarm_deadline (tain_t const *) ; +extern void alarm_disable (void) ; + +#endif diff --git a/src/include/skalibs/stddjb.h b/src/include/skalibs/stddjb.h index e265003..3ebd219 100644 --- a/src/include/skalibs/stddjb.h +++ b/src/include/skalibs/stddjb.h @@ -15,6 +15,7 @@ #include #include +#include #include #include #include diff --git a/src/libstddjb/alarm-internal.h b/src/libstddjb/alarm-internal.h new file mode 100644 index 0000000..027a0dc --- /dev/null +++ b/src/libstddjb/alarm-internal.h @@ -0,0 +1,14 @@ +/* ISC license. */ + +#ifndef ALARM_INTERNAL_H +#define ALARM_INTERNAL_H + +#ifdef SKALIBS_HASTIMER + +#include + +extern timer_t timer_here ; + +#endif + +#endif diff --git a/src/libstddjb/alarm_deadline.c b/src/libstddjb/alarm_deadline.c new file mode 100644 index 0000000..768ee5c --- /dev/null +++ b/src/libstddjb/alarm_deadline.c @@ -0,0 +1,47 @@ +/* ISC license. */ + +#include +#include +#include + +#ifdef SKALIBS_HASTIMER + +#include +#include +#include +#include "alarm-internal.h" + +#undef MYCLOCK +#ifdef SKALIBS_HASCLOCKMON +# define MYCLOCK CLOCK_MONOTONIC +#else +# define MYCLOCK CLOCK_REALTIME +#endif + +int alarm_deadline (tain_t const *deadline) +{ + struct itimerspec it = { .it_interval = { .tv_sec = 0, .tv_nsec = 0 } } ; + struct sigevent se = { .sigev_notify = SIGEV_SIGNAL, .sigev_signo = SIGALRM, .sigev_value = { .sival_int = 0 }, .sigev_notify_function = 0, .sigev_notify_attributes = 0 } ; + if (!timespec_from_tain(&it.it_value, deadline)) return 0 ; + if (timer_create(MYCLOCK, &se, &timer_here) < 0) return 0 ; + if (timer_settime(timer_here, TIMER_ABSTIME, &it, 0) < 0) + { + int e = errno ; + timer_delete(timer_here) ; + errno = e ; + return 0 ; + } + return 1 ; +} + +#else + +int alarm_deadline (tain_t const *deadline) +{ + tain_t tto ; + tain_now(&tto) ; + tain_sub(&tto, deadline, &tto) ; + return alarm_timeout(&tto) ; +} + +#endif diff --git a/src/libstddjb/alarm_disable.c b/src/libstddjb/alarm_disable.c new file mode 100644 index 0000000..a383411 --- /dev/null +++ b/src/libstddjb/alarm_disable.c @@ -0,0 +1,41 @@ +/* ISC license. */ + +#include +#include + +#ifdef SKALIBS_HASTIMER + +#include +#include "alarm-internal.h" + +timer_t timer_here ; + +void alarm_disable () +{ + struct itimerspec stopit = { .it_value = { .tv_sec = 0, .tv_nsec = 0 }, .it_interval = { .tv_sec = 0, .tv_nsec = 0 } } ; + timer_settime(timer_here, 0, &stopit, 0) ; + timer_delete(timer_here) ; +} + +#else +#ifdef SKALIBS_HASITIMER + +#include + +void alarm_disable () +{ + struct itimerval stopit = { .it_value = { .tv_sec = 0, .tv_usec = 0 }, .it_interval = { .tv_sec = 0, .tv_usec = 0 } } ; + setitimer(ITIMER_REAL, &stopit, 0) ; +} + +#else + +#include + +void alarm_disable () +{ + alarm(0) ; +} + +#endif +#endif diff --git a/src/libstddjb/alarm_milliseconds.c b/src/libstddjb/alarm_milliseconds.c new file mode 100644 index 0000000..0628518 --- /dev/null +++ b/src/libstddjb/alarm_milliseconds.c @@ -0,0 +1,61 @@ +/* ISC license. */ + +#include +#include + +#ifdef SKALIBS_HASTIMER + +#include +#include +#include +#include "alarm-internal.h" + +#undef MYCLOCK +#ifdef SKALIBS_HASCLOCKMON +# define MYCLOCK CLOCK_MONOTONIC +#else +# define MYCLOCK CLOCK_REALTIME +#endif + +int alarm_milliseconds (unsigned int t) +{ + struct itimerspec it = { .it_interval = { .tv_sec = 0, .tv_nsec = 0 }, .it_value = { .tv_sec = t / 1000, .tv_nsec = 1000000 * (t % 1000) } } ; + struct sigevent se = { .sigev_notify = SIGEV_SIGNAL, .sigev_signo = SIGALRM, .sigev_value = { .sival_int = 0 }, .sigev_notify_function = 0, .sigev_notify_attributes = 0 } ; + if (timer_create(MYCLOCK, &se, &timer_here) < 0) return 0 ; + if (timer_settime(timer_here, 0, &it, 0) < 0) + { + int e = errno ; + timer_delete(timer_here) ; + errno = e ; + return 0 ; + } + return 1 ; +} + +#else +#ifdef SKALIBS_HASITIMER + +#include + +int alarm_milliseconds (unsigned int t) +{ + struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 0 }, .it_value = { .tv_sec = t / 1000, .tv_usec = 1000 * (t % 1000) } } ; + if (setitimer(ITIMER_REAL, &it, 0) < 0) return 0 ; + return 1 ; +} + +#else + +#include +#include + +int alarm_milliseconds (unsigned int t) +{ + if (t > UINT_MAX - 999) return 0 ; + t = (t + 999) / 1000 ; + alarm(t) ; + return 1 ; +} + +#endif +#endif diff --git a/src/libstddjb/alarm_timeout.c b/src/libstddjb/alarm_timeout.c new file mode 100644 index 0000000..630b524 --- /dev/null +++ b/src/libstddjb/alarm_timeout.c @@ -0,0 +1,65 @@ +/* ISC license. */ + +#include +#include +#include + +#ifdef SKALIBS_HASTIMER + +#include +#include +#include +#include "alarm-internal.h" + +#undef MYCLOCK +#ifdef SKALIBS_HASCLOCKMON +# define MYCLOCK CLOCK_MONOTONIC +#else +# define MYCLOCK CLOCK_REALTIME +#endif + +int alarm_timeout (tain_t const *tto) +{ + struct itimerspec it = { .it_interval = { .tv_sec = 0, .tv_nsec = 0 } } ; + struct sigevent se = { .sigev_notify = SIGEV_SIGNAL, .sigev_signo = SIGALRM, .sigev_value = { .sival_int = 0 }, .sigev_notify_function = 0, .sigev_notify_attributes = 0 } ; + if (!timespec_from_tain_relative(&it.it_value, tto)) return 0 ; + if (timer_create(MYCLOCK, &se, &timer_here) < 0) return 0 ; + if (timer_settime(timer_here, 0, &it, 0) < 0) + { + int e = errno ; + timer_delete(timer_here) ; + errno = e ; + return 0 ; + } + return 1 ; +} + +#else +#ifdef SKALIBS_HASITIMER + +#include + +int alarm_timeout (tain_t const *tto) +{ + struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 0 } } ; + if (!timeval_from_tain_relative(&it.it_value, tto)) return 0 ; + if (setitimer(ITIMER_REAL, &it, 0) < 0) return 0 ; + return 1 ; +} + +#else + +#include +#include + +int alarm_timeout (tain_t const *tto) +{ + int t = tain_to_millisecs(tto) ; + if (t < 0 || t > INT_MAX - 999) return 0 ; + t = (t + 999) / 1000 ; + alarm(t) ; + return 1 ; +} + +#endif +#endif diff --git a/src/libstddjb/alloc-internal.h b/src/libstddjb/alloc-internal.h index 918b5df..6fd312e 100644 --- a/src/libstddjb/alloc-internal.h +++ b/src/libstddjb/alloc-internal.h @@ -1,7 +1,7 @@ /* ISC license. */ -#ifndef ALLOC_0_H -#define ALLOC_0_H +#ifndef ALLOC_INTERNAL_H +#define ALLOC_INTERNAL_H #include #include diff --git a/src/sysdeps/tryitimer.c b/src/sysdeps/tryitimer.c new file mode 100644 index 0000000..4fd3454 --- /dev/null +++ b/src/sysdeps/tryitimer.c @@ -0,0 +1,10 @@ +/* ISC license. */ + +#include + +int main (void) +{ + struct itimerval blah ; + if (getitimer(ITIMER_REAL, &blah) < 0) return 111 ; + return 0 ; +} diff --git a/src/sysdeps/trytimer.c b/src/sysdeps/trytimer.c new file mode 100644 index 0000000..84cea0d --- /dev/null +++ b/src/sysdeps/trytimer.c @@ -0,0 +1,12 @@ +/* ISC license. */ + +#include +#include +#include + +int main (void) +{ + timer_t blah ; + if (timer_create(CLOCK_REALTIME, 0, &blah) < 0) return 111 ; + return 0 ; +} -- cgit v1.3.1

The alarm library interface

General information

Functions

Notes

Programming

The `alarm` library interface