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elinks/src/network/progress.c
Kalle Olavi Niemitalo d6fd2ac31f Erase progress.timer before calling progress.timer_func
Previously, each progress timer function registered with
start_update_progress() was directly used as the timer function of
progress.timer, so it was responsible of erasing the expired timer ID
from that member.  Failing to do this could result in heap corruption.
The progress timer functions normally fulfilled the requirement by
calling update_progress(), but one such function upload_stat_timer()
had to erase the timer ID on its own too.

Now instead, there is a wrapper function progress_timeout(), which
progress.c sets as the timer function of progress.timer.  This wrapper
erases the expired timer ID from progress.timer and then calls the
progress timer function registered with start_update_progress().  So
the progress timer function is no longer responsible of erasing the
timer ID and there's no risk that it could fail to do that in some
error situation.

This commit introduces a new risk though.  Previously, if the struct
progress was freed while the timer was running, the (progress) timer
function would still be called, and it would be able to detect that
the progress pointer is NULL and recover from this situation.  Now,
the timer function progress_timeout() has a pointer to the struct
progress and will dereference that pointer without being able to check
whether the structure has been freed.  Fortunately, done_progress()
asserts that the timer is not running, so this should not occur.
2008-06-15 11:27:19 +03:00

132 lines
3.7 KiB
C

/* Downloads progression stuff. */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "elinks.h"
#include "network/progress.h"
#include "util/error.h"
#include "util/memory.h"
#include "util/time.h"
#define SPD_DISP_TIME ((milliseconds_T) 100)
#define CURRENT_SPD_AFTER ((milliseconds_T) 100)
int
has_progress(struct progress *progress)
{
timeval_T current_speed_after;
timeval_from_milliseconds(&current_speed_after, CURRENT_SPD_AFTER);
return (timeval_cmp(&progress->elapsed, &current_speed_after) >= 0);
}
struct progress *
init_progress(off_t start)
{
struct progress *progress = mem_calloc(1, sizeof(*progress));
if (progress) {
progress->start = start;
progress->timer = TIMER_ID_UNDEF;
}
return progress;
}
void
done_progress(struct progress *progress)
{
assert(progress->timer == TIMER_ID_UNDEF);
mem_free(progress);
}
/** Timer callback for progress.timer. As explained in install_timer(),
* this function must erase the expired timer ID from all variables. */
static void
progress_timeout(void *progress_voidptr)
{
struct progress *const progress = progress_voidptr;
progress->timer = TIMER_ID_UNDEF;
/* The expired timer ID has now been erased. */
progress->timer_func(progress->timer_func_data);
}
/* Usually called from the timer callback of @progress->timer. */
void
update_progress(struct progress *progress, off_t loaded, off_t size, off_t pos)
{
off_t bytes_delta;
timeval_T now, elapsed, dis_b_max, dis_b_interval;
timeval_now(&now);
timeval_sub(&elapsed, &progress->last_time, &now);
timeval_copy(&progress->last_time, &now);
progress->loaded = loaded;
bytes_delta = progress->loaded - progress->last_loaded;
progress->last_loaded = progress->loaded;
timeval_add_interval(&progress->elapsed, &elapsed);
timeval_add_interval(&progress->dis_b, &elapsed);
timeval_from_milliseconds(&dis_b_max, mult_ms(SPD_DISP_TIME, CURRENT_SPD_SEC));
timeval_from_milliseconds(&dis_b_interval, SPD_DISP_TIME);
while (timeval_cmp(&progress->dis_b, &dis_b_max) >= 0) {
progress->cur_loaded -= progress->data_in_secs[0];
memmove(progress->data_in_secs, progress->data_in_secs + 1,
sizeof(*progress->data_in_secs) * (CURRENT_SPD_SEC - 1));
progress->data_in_secs[CURRENT_SPD_SEC - 1] = 0;
timeval_sub_interval(&progress->dis_b, &dis_b_interval);
}
progress->data_in_secs[CURRENT_SPD_SEC - 1] += bytes_delta;
progress->cur_loaded += bytes_delta;
progress->current_speed = progress->cur_loaded / (CURRENT_SPD_SEC * ((long) SPD_DISP_TIME) / 1000);
progress->pos = pos;
progress->size = size;
if (progress->size != -1 && progress->size < progress->pos)
progress->size = progress->pos;
progress->average_speed = timeval_div_off_t(progress->loaded, &progress->elapsed);
if (progress->average_speed) /* Division by zero risk */
timeval_from_seconds(&progress->estimated_time,
(progress->size - progress->pos) / progress->average_speed);
install_timer(&progress->timer, SPD_DISP_TIME,
progress_timeout, progress);
}
/*! Unlike in install_timer(), @a timer_func need not erase the
* expired timer ID from @a progress->timer. update_progress()
* installs the timer with a wrapper function that takes care of
* erasing the timer ID. */
void
start_update_progress(struct progress *progress, void (*timer_func)(void *),
void *timer_func_data)
{
if (!progress->valid) {
struct progress tmp;
/* Just copy useful fields from invalid progress. */
memset(&tmp, 0, sizeof(tmp));
tmp.start = progress->start;
tmp.seek = progress->seek;
tmp.valid = 1;
memcpy(progress, &tmp, sizeof(*progress));
}
timeval_now(&progress->last_time);
progress->last_loaded = progress->loaded;
progress->timer_func = timer_func;
progress->timer_func_data = timer_func_data;
}