adns_if_noautosys= 0x0010,/* do not make syscalls at every opportunity */
adns_if_eintr= 0x0020,/* allow _wait and _synchronous to return EINTR */
adns_if_nosigpipe= 0x0040,/* applic has SIGPIPE ignored, do not protect */
+ adns_if_monotonic= 0x0080,/* enable if you can; see adns_processtimeouts */
adns_if_checkc_entex=0x0100,/* consistency checks on entry/exit to adns fns */
adns_if_checkc_freq= 0x0300,/* consistency checks very frequently (slow!) */
* these approaches has optimal performance.
*/
+/*
+ * Use of time:
+ *
+ * adns needs to manipulate timeouts. For API compatibility reasons
+ * (adns predates clock_gettime) the default is to use wall clock time
+ * from gettimeofday. This will malfunction if the system clock is
+ * not suitably stable. To avoid this, you should set
+ * adns_if_monotonic
+ *
+ * If you specify adns_if_monotonic then all `now' values passed to
+ * adns must be from clock_gettime(CLOCK_MONOTONIC). clock_gettime
+ * returns a struct timespec; you must convert it to a struct timeval
+ * by dividing the nsec by 1000 to make usec, rounding down.
+ */
+
int adns_init(adns_state *newstate_r, adns_initflags flags,
FILE *diagfile /*0=>stderr*/);
* use that fd and only in the manner specified, regardless of whether
* adns_if_noautosys was specified.
*
+ * now is as for adns_processtimeouts.
+ *
* adns_processexceptional should be called when select(2) reports an
* exceptional condition, or poll(2) reports POLLPRI.
*
/* Gives adns flow-of-control so that it can process any timeouts
* which might have happened. Very like _processreadable/writeable.
*
- * now may be 0; if it isn't, *now must be the current time, recently
- * obtained from gettimeofday.
+ * now may be 0; if it isn't, *now must be the current time from
+ * gettimeofday, or iff adns_if_monotonic it must be converted
+ * from the results of clock_gettime(CLOCK_MONOTONIC) (with the
+ * timespec.tv_nsec rounded down to make timeval.tv_usec).
*/
void adns_firsttimeout(adns_state ads,
struct timeval **tv_mod, struct timeval *tv_buf,
struct timeval now);
/* Asks adns when it would first like the opportunity to time
- * something out. now must be the current time, from gettimeofday.
+ * something out.
+ *
+ * now must be the current time, as for adns_processtimeouts.
*
* If tv_mod points to 0 then tv_buf must be non-null, and
* _firsttimeout will fill in *tv_buf with the time until the first
* adns_s_systemfail, and adns will close any stream sockets it has
* open.
*
- * This is used by adns, for example, if gettimeofday() fails.
- * Without this the program's event loop might start to spin !
+ * This is used by adns, for example, if gettimeofday() or
+ * clock_gettime fails. Without this the program's event loop might
+ * start to spin !
*
* This call will never block.
*/
/* Find out file descriptors adns is interested in, and when it would
* like the opportunity to time something out. If you do not plan to
* block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as
- * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may
+ * for adns_processtimeouts. readfds, writefds, exceptfds and maxfd_io may
* not be 0.
*
+ * now is as for adns_processtimeouts.
+ *
* If tv_mod is 0 on entry then this will never actually do any I/O,
* or change the fds that adns is using or the timeouts it wants. In
* any case it won't block, and it will set the timeout to zero if a
* select. This is just a fancy way of calling adns_processreadable/
* writeable/timeouts as appropriate, as if select had returned the
* data being passed. Always succeeds.
+ *
+ * now is as for adns_processtimeouts.
*/
/*
* descriptors, and use _firsttimeout is used to find out when adns
* might want to time something out.)
*
+ * now is as for adns_processtimeouts.
+ *
* adns_beforepoll will return 0 on success, and will not fail for any
* reason other than the fds buffer being too small (ERANGE).
*
/* Gives adns flow-of-control for a bit; intended for use after
* poll(2). fds and nfds should be the results from poll(). pollfd
* structs mentioning fds not belonging to adns will be ignored.
+ *
+ * now is as for adns_processtimeouts.
*/
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
+#include <time.h>
#include "internal.h"
#include "tvarith.h"
/* Timeout handling functions. */
+int adns__gettimeofday(adns_state ads, struct timeval *tv) {
+ if (!(ads->iflags & adns_if_monotonic))
+ return gettimeofday(tv,0);
+
+ struct timespec ts;
+ int r = clock_gettime(CLOCK_MONOTONIC,&ts);
+ if (r) return r;
+
+ tv->tv_sec = ts.tv_sec;
+ tv->tv_usec = ts.tv_nsec / 1000;
+ return 0;
+}
+
void adns__must_gettimeofday(adns_state ads, const struct timeval **now_io,
struct timeval *tv_buf) {
const struct timeval *now;
now= *now_io;
if (now) return;
- r= gettimeofday(tv_buf,0); if (!r) { *now_io= tv_buf; return; }
- adns__diag(ads,-1,0,"gettimeofday failed: %s",strerror(errno));
+ r= adns__gettimeofday(ads,tv_buf); if (!r) { *now_io= tv_buf; return; }
+ adns__diag(ads,-1,0,"gettimeofday/clock_gettime failed: %s",
+ strerror(errno));
adns_globalsystemfailure(ads);
return;
}
adns__consistency(ads,0,cc_enter);
- r= gettimeofday(&now,0);
+ r= adns__gettimeofday(ads,&now);
if (!r) adns_processtimeouts(ads,&now);
/* We just use adns__fdevents to loop over the fd's trying them.
int r;
adns__consistency(ads,*query_io,cc_enter);
- r= gettimeofday(&now,0);
+ r= adns__gettimeofday(ads,&now);
if (!r) adns__autosys(ads,now);
r= adns__internal_check(ads,query_io,answer_r,context_r);
* settled on.
*/
adns__cancel_children(parent);
- r= gettimeofday(&now, 0); if (r) goto x_gtod;
+ r= adns__gettimeofday(ads,&now); if (r) goto x_gtod;
qf= adns__qf_addr_cname;
if (!(parent->flags & adns_qf_cname_loose)) qf |= adns_qf_cname_forbid;
addr_subqueries(parent, now, qf, child->vb.buf, child->vb.used);
adns__cancel_children(parent);
adns__free_interim(parent, pans->rrs.bytes);
pans->rrs.bytes= 0; pans->nrrs= 0;
- r= gettimeofday(&now, 0); if (r) goto x_gtod;
+ r= adns__gettimeofday(ads,&now); if (r) goto x_gtod;
adns__search_next(ads, parent, now);
return;
}
/* We have our own error handling, because adns__must_gettimeofday
* handles errors by calling adns_globalsystemfailure, which would
* reenter the query processing logic. */
- adns__diag(ads, -1, parent, "gettimeofday failed: %s", strerror(errno));
+ adns__diag(ads, -1, parent, "gettimeofday/clock_gettime failed: %s",
+ strerror(errno));
err= adns_s_systemfail;
goto x_err;