On 16/07/11 20:28, Paul Eggert wrote: > setitimer has nanosecond resolution, which is better than the > one-second resolution that 'alarm' has. timeout should use > setitimer if available, to take advantage of this. On 64-bit > hosts, this has the additional advantage of increasing the > upper bound for timeouts from 2**31 seconds to 2**63 seconds > (about 68 years to about 292 billion years, which should be > long enough for most practical purposes :-).
I'll apply this soon. cheers, Pádraig.
>From 057796b81c0de662700a801d49426e9e56e5bc44 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A1draig=20Brady?= <[email protected]> Date: Mon, 18 Jul 2011 10:49:17 +0100 Subject: [PATCH] timeout: support sub-second timeouts * src/timeout.c (settimeout): A new function to convert from a floating point duration and all alarm() or setitimer() if that's available. (parse_duration): Return a double rather than unsigned int. (usage): Mention floating point supported. (main): Pass the double to settimeout() rather than calling alarm() directly with the parsed int. (cleanup): Likewise. * doc/coreutils.texi (timeout invocation): Say floating point timeouts now supported, and mention the caveat with resolution. * m4/jm-macros.m4: Check for setitimer. * tests/misc/timeout-parameters: Add a test for the nanosecond to microsecond conversion boundary. * NEWS: Mention the improvement. --- NEWS | 2 + doc/coreutils.texi | 4 ++- m4/jm-macros.m4 | 5 ++- src/timeout.c | 65 +++++++++++++++++++++++++++++------------ tests/misc/timeout-parameters | 3 ++ 5 files changed, 58 insertions(+), 21 deletions(-) diff --git a/NEWS b/NEWS index c382200..2119f64 100644 --- a/NEWS +++ b/NEWS @@ -50,6 +50,8 @@ GNU coreutils NEWS -*- outline -*- stat -f now recognizes the GPFS, MQUEUE and PSTOREFS file system types. + timeout allows sub-second timeouts where supported. + ** Build-related Changes inherited from gnulib address a build failure on HP-UX 11.11 diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 424446c..b406a3c 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -15694,7 +15694,7 @@ or a number. Also see @xref{Signal specifications}. @end table @cindex time units -@var{duration} is an integer followed by an optional unit: +@var{duration} is a floating point number followed by an optional unit: @display @samp{s} for seconds (the default) @samp{m} for minutes @@ -15702,6 +15702,8 @@ or a number. Also see @xref{Signal specifications}. @samp{d} for days @end display A duration of 0 disables the associated timeout. +Note that the actual timeout duration is dependent on system conditions, +which should be especially considered when specifying sub-second timeouts. @cindex exit status of @command{timeout} Exit status: diff --git a/m4/jm-macros.m4 b/m4/jm-macros.m4 index 9bb6fa4..fa75708 100644 --- a/m4/jm-macros.m4 +++ b/m4/jm-macros.m4 @@ -66,7 +66,10 @@ AC_DEFUN([coreutils_MACROS], # Used by sort.c. AC_CHECK_FUNCS_ONCE([nl_langinfo]) # Used by timeout.c - AC_CHECK_FUNCS_ONCE([setrlimit]) + AC_CHECK_FUNCS_ONCE( \ + setrlimit \ + setitimer \ + ) # Used by tail.c. AC_CHECK_FUNCS([inotify_init], diff --git a/src/timeout.c b/src/timeout.c index ccb4f85..bbbe8c3 100644 --- a/src/timeout.c +++ b/src/timeout.c @@ -78,7 +78,7 @@ static int timed_out; static int term_signal = SIGTERM; /* same default as kill command. */ static int monitored_pid; static int sigs_to_ignore[NSIG]; /* so monitor can ignore sigs it resends. */ -static unsigned long kill_after; +static double kill_after; static bool foreground; /* whether to use another program group. */ /* for long options with no corresponding short option, use enum */ @@ -97,6 +97,45 @@ static struct option const long_options[] = {NULL, 0, NULL, 0} }; +/* Start the timeout after which we'll receive a SIGALRM. + Round DURATION up to the next representable value. + Treat out-of-range values as if they were maximal, + as that's more useful in practice than reporting an error. + '0' means don't timeout. */ +static void +settimeout (double duration) +{ +#if HAVE_SETITIMER + struct timeval tv; + struct timespec ts = dtotimespec (duration); + tv.tv_sec = MIN (ts.tv_sec, LONG_MAX); /* Assuming tv_sec is positive. */ + tv.tv_usec = (ts.tv_nsec + 999) / 1000; + if (tv.tv_usec == 1000 * 1000) + { + if (tv.tv_sec != LONG_MAX) + { + tv.tv_sec++; + tv.tv_usec = 0; + } + else + tv.tv_usec--; + } + struct itimerval it = { {0, 0}, tv }; + if (setitimer (ITIMER_REAL, &it, NULL) == -1) + error (EXIT_FAILURE, errno, _("error setting timer")); +#else + unsigned int timeint; + if (UINT_MAX <= duration) + timeint = UINT_MAX; + else + { + unsigned int duration_floor = duration; + timeint = duration_floor + (duration_floor < duration); + } + alarm (timeint); +#endif +} + /* send sig to group but not ourselves. * FIXME: Is there a better way to achieve this? */ static int @@ -125,7 +164,7 @@ cleanup (int sig) { /* Start a new timeout after which we'll send SIGKILL. */ term_signal = SIGKILL; - alarm (kill_after); + settimeout (kill_after); kill_after = 0; /* Don't let later signals reset kill alarm. */ } @@ -182,7 +221,7 @@ Mandatory arguments to long options are mandatory for short options too.\n\ fputs (VERSION_OPTION_DESCRIPTION, stdout); fputs (_("\n\ -DURATION is an integer with an optional suffix:\n\ +DURATION is a floating point number with an optional suffix:\n\ `s' for seconds (the default), `m' for minutes, `h' for hours \ or `d' for days.\n"), stdout); @@ -232,7 +271,7 @@ apply_time_suffix (double *x, char suffix_char) return true; } -static unsigned int +static double parse_duration (const char* str) { double duration; @@ -250,19 +289,7 @@ parse_duration (const char* str) usage (EXIT_CANCELED); } - /* Return the requested duration, rounded up to the next representable value. - Treat out-of-range values as if they were maximal, - as that's more useful in practice than reporting an error. - - FIXME: Use dtotimespec + setitimer if setitimer is available, - as that has higher resolution. */ - if (UINT_MAX <= duration) - return UINT_MAX; - else - { - unsigned int duration_floor = duration; - return duration_floor + (duration_floor < duration); - } + return duration; } static void @@ -285,7 +312,7 @@ install_signal_handlers (int sigterm) int main (int argc, char **argv) { - unsigned long timeout; + double timeout; char signame[SIG2STR_MAX]; int c; @@ -373,7 +400,7 @@ main (int argc, char **argv) pid_t wait_result; int status; - alarm (timeout); + settimeout (timeout); while ((wait_result = waitpid (monitored_pid, &status, 0)) < 0 && errno == EINTR) diff --git a/tests/misc/timeout-parameters b/tests/misc/timeout-parameters index 56804a8..e99d4a5 100755 --- a/tests/misc/timeout-parameters +++ b/tests/misc/timeout-parameters @@ -55,6 +55,9 @@ test $? = 0 || fail=1 timeout 2.34e+5d sleep 0 test $? = 0 || fail=1 +# nanoseconds rounded up to microseconds +timeout .999999999 sleep 0 || fail=1 + # invalid signal spec timeout --signal=invalid 1 sleep 0 test $? = 125 || fail=1 -- 1.7.5.2
