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Add timed signal interruption to the read side as well as the write, so that a non-write transfer method like splice or copy_file_range will still get interrupted if it takes too long.

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This commit is contained in:
Andrew Wood
2026-06-05 23:30:49 +01:00
parent 5971d622bd
commit d075ddf1ed
1 changed files with 86 additions and 54 deletions
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src/pv/transfer.c
+86 -54
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@@ -106,6 +106,86 @@ static int is_data_ready(int fd_in, /*@null@ */ bool *fd_in_ready, int fd_out, /
}
/*
* Set a timer that will raise a signal after "interval" seconds, repeating
* if setitimer() is available. This is used by calling functions to ensure
* that progress information continues to be updated, by interrupting any
* subsequent write, splice, etc that takes too long.
*/
static void interrupter_start(double interval)
{
#if HAVE_SETITIMER
struct itimerval new_timer;
/*@-unrecog@ */
/* splint doesn't know setitimer or ITIMER_REAL. */
memset(&new_timer, 0, sizeof(new_timer));
new_timer.it_value.tv_sec = (time_t) (interval);
new_timer.it_value.tv_usec = (suseconds_t) (((long) (interval * 1000000.0)) % 1000000);
/*
* The interval has to be set so that the timer continues to
* repeat while writes are attempted, especially as it's
* possible that the initial timer run will expire
* immediately if the period is less than 1 second.
*/
new_timer.it_interval.tv_sec = new_timer.it_value.tv_sec;
new_timer.it_interval.tv_usec = new_timer.it_value.tv_usec;
debug("%s: [%lds,%ldus]", "setting interval timer", (long) (new_timer.it_value.tv_sec),
(long) (new_timer.it_value.tv_usec));
if (0 != setitimer(ITIMER_REAL, &new_timer, NULL)) {
/*
* Record failure only as debugging information,
* since if this call failed, it's not actionable by
* the user and would only clutter the display.
*/
debug("%s: %s", "setitimer (set) failed", strerror(errno));
}
/*@+unrecog@ */
#else /* ! HAVE_SETITIMER */
(void) alarm(1);
debug("%s", "setting alarm");
#endif /* HAVE_SETITIMER */
}
/*
* Stop the signal interrupt generation timer. Note that errno is
* preserved.
*/
static void interrupter_stop(void)
{
int old_errno = errno;
#if HAVE_SETITIMER
struct itimerval new_timer;
/*@-unrecog@ */
/* splint doesn't know setitimer or ITIMER_REAL. */
memset(&new_timer, 0, sizeof(new_timer));
new_timer.it_interval.tv_sec = 0;
new_timer.it_interval.tv_usec = 0;
new_timer.it_value.tv_sec = 0;
new_timer.it_value.tv_usec = 0;
if (0 != setitimer(ITIMER_REAL, &new_timer, NULL)) {
/* Debug output only, as above. */
debug("%s: %s", "setitimer (clear) failed", strerror(errno));
}
/*@+unrecog@ */
#else /* ! HAVE_SETITIMER */
debug("%s", "cancelling alarm");
(void) alarm(0);
#endif /* HAVE_SETITIMER */
errno = old_errno;
}
/*
* Read up to "count" bytes from file descriptor "fd" into the buffer "buf",
* in chunks of no more than MAX_READ_AT_ONCE bytes at a time.
@@ -920,6 +1000,8 @@ static bool pv__transfer_read(pvstate_t state, int input_fd, bool *eof_in, bool
* transfer_attempted to false, so this loop will go around
* again.
*/
/* Ensure the read is interrupted if it takes too long. */
interrupter_start(state->control.interval);
transfer_attempted = true;
switch (state->transfer.method) {
case PV_TRANSFERMETHOD_COPY_FILE_RANGE:
@@ -948,6 +1030,7 @@ static bool pv__transfer_read(pvstate_t state, int input_fd, bool *eof_in, bool
(size_t) max_to_read_into_buffer);
break;
}
interrupter_stop();
}
/*
@@ -1309,46 +1392,9 @@ static bool pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, lon
}
}
/*
* Set an interval timer or an alarm to interrupt the write
* with a signal if the write takes too long, so progress
* information can continue to be produced.
*/
#if HAVE_SETITIMER
struct itimerval new_timer;
/* Ensure the write is interrupted if it takes too long. */
interrupter_start(state->control.interval);
/*@-unrecog@ */
/* splint doesn't know setitimer or ITIMER_REAL. */
memset(&new_timer, 0, sizeof(new_timer));
new_timer.it_value.tv_sec = (time_t) (state->control.interval);
new_timer.it_value.tv_usec = (suseconds_t) (((long) (state->control.interval * 1000000.0)) % 1000000);
/*
* The interval has to be set so that the timer continues to
* repeat while writes are attempted, especially as it's
* possible that the initial timer run will expire
* immediately if the period is less than 1 second.
*/
new_timer.it_interval.tv_sec = new_timer.it_value.tv_sec;
new_timer.it_interval.tv_usec = new_timer.it_value.tv_usec;
debug("%s: [%lds,%ldus]", "setting interval timer", (long) (new_timer.it_value.tv_sec),
(long) (new_timer.it_value.tv_usec));
if (0 != setitimer(ITIMER_REAL, &new_timer, NULL)) {
/*
* Record failure only as debugging information,
* since if this call failed, it's not actionable by
* the user and would only clutter the display.
*/
debug("%s: %s", "setitimer (set) failed", strerror(errno));
}
#else /* ! HAVE_SETITIMER */
(void) alarm(1);
debug("%s", "setting alarm");
#endif /* HAVE_SETITIMER */
debug("%s: %ld %s", "beginning write attempt", (long) (state->transfer.to_write), "bytes");
nwritten = pv__transfer__write_repeated(state->control.output_fd,
state->transfer.transfer_buffer +
@@ -1361,22 +1407,8 @@ static bool pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, lon
} else {
debug("%s: %ld", "bytes written", (long) nwritten);
}
#if HAVE_SETITIMER
memset(&new_timer, 0, sizeof(new_timer));
new_timer.it_interval.tv_sec = 0;
new_timer.it_interval.tv_usec = 0;
new_timer.it_value.tv_sec = 0;
new_timer.it_value.tv_usec = 0;
if (0 != setitimer(ITIMER_REAL, &new_timer, NULL)) {
/* Debug output only, as above. */
debug("%s: %s", "setitimer (clear) failed", strerror(errno));
}
/*@+unrecog@ */
#else /* ! HAVE_SETITIMER */
debug("%s", "cancelling alarm");
(void) alarm(0);
#endif /* HAVE_SETITIMER */
interrupter_stop();
}
pv__transfer_write_completed: