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curl_easy_perform_ev: debug/test function

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This function is meant to work *exactly* as curl_easy_perform() but will
use the event-based libcurl API internally instead of
curl_multi_perform(). To avoid relying on an actual event-based library
and to not use non-portable functions (like epoll or similar), there's a
rather inefficient emulation layer implemented on top of Curl_poll()
instead.

There's currently some convenience logging done in curl_easy_perform_ev
which helps when tracking down problems. They may be suitable to remove
or change once things seem to be fine enough.

curl has a new --test-event option when built with debug enabled that
then uses curl_easy_perform_ev() instead of curl_easy_perform(). If
built without debug, using --test-event will only output a warning
message.

NOTE: curl_easy_perform_ev() is not part if the public API on purpose.
It is only present in debug builds of libcurl and MUST NOT be considered
stable even then. Use it for libcurl-testing purposes only.

runtests.pl now features an -e command line option that makes it use
--test-event for all curl command line tests. The man page is updated.
This commit is contained in:
Daniel Stenberg
2013-08-10 22:55:59 +02:00
parent 062e5bfd9c
commit 6cf8413e31
7 changed files with 414 additions and 66 deletions
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414
lib/easy.c
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@@ -453,70 +453,275 @@ CURLcode curl_easy_setopt(CURL *curl, CURLoption tag, ...)
return ret;
}
/*
* curl_easy_perform() is the external interface that performs a blocking
* transfer as previously setup.
#ifdef CURLDEBUG
struct monitor {
struct monitor *next; /* the next node in the list or NULL */
struct pollfd socket; /* socket info of what to monitor */
};
struct events {
long ms; /* timeout, run the timeout function when reached */
bool msbump; /* set TRUE when timeout is set by callback */
int num_sockets; /* number of nodes in the monitor list */
struct monitor *list; /* list of sockets to monitor */
int running_handles; /* store the returned number */
};
/* events_timer
*
* CONCEPT: This function creates a multi handle, adds the easy handle to it,
* runs curl_multi_perform() until the transfer is done, then detaches the
* easy handle, destroys the multi handle and returns the easy handle's return
* code.
*
* REALITY: it can't just create and destroy the multi handle that easily. It
* needs to keep it around since if this easy handle is used again by this
* function, the same multi handle must be re-used so that the same pools and
* caches can be used.
* Callback that gets called with a new value when the timeout should be
* updated.
*/
CURLcode curl_easy_perform(CURL *easy)
static int events_timer(CURLM *multi, /* multi handle */
long timeout_ms, /* see above */
void *userp) /* private callback pointer */
{
struct events *ev = userp;
(void)multi;
if(timeout_ms == -1)
/* timeout removed */
timeout_ms = 0;
else if(timeout_ms == 0)
/* timeout is already reached! */
timeout_ms = 1; /* trigger asap */
ev->ms = timeout_ms;
ev->msbump = TRUE;
/* fprintf(stderr, "%s: timeout %ld\n", __func__, timeout_ms); */
return 0;
}
/* poll2cselect
*
* convert from poll() bit definitions to libcurl's CURL_CSELECT_* ones
*/
static int poll2cselect(int pollmask)
{
int omask=0;
if(pollmask & POLLIN)
omask |= CURL_CSELECT_IN;
if(pollmask & POLLOUT)
omask |= CURL_CSELECT_OUT;
if(pollmask & POLLERR)
omask |= CURL_CSELECT_ERR;
return omask;
}
/* socketcb2poll
*
* convert from libcurl' CURL_POLL_* bit definitions to poll()'s
*/
static short socketcb2poll(int pollmask)
{
short omask=0;
if(pollmask & CURL_POLL_IN)
omask |= POLLIN;
if(pollmask & CURL_POLL_OUT)
omask |= POLLOUT;
return omask;
}
/* events_socket
*
* Callback that gets called with information about socket activity to
* monitor.
*/
static int events_socket(CURL *easy, /* easy handle */
curl_socket_t s, /* socket */
int what, /* see above */
void *userp, /* private callback
pointer */
void *socketp) /* private socket
pointer */
{
struct events *ev = userp;
struct monitor *m;
struct monitor *prev=NULL;
(void)socketp;
m = ev->list;
while(m) {
if(m->socket.fd == s) {
if(what == CURL_POLL_REMOVE) {
struct monitor *nxt = m->next;
/* remove this node from the list of monitored sockets */
if(prev)
prev->next = nxt;
else
ev->list = nxt;
free(m);
m = nxt;
infof(easy, "socket cb: socket %d REMOVED\n", s);
}
else {
/* The socket 's' is already being monitored, update the activity
mask. Convert from libcurl bitmask to the poll one. */
m->socket.events = socketcb2poll(what);
infof(easy, "socket cb: socket %d UPDATED as %s%s\n", s,
what&CURL_POLL_IN?"IN":"",
what&CURL_POLL_OUT?"OUT":"");
}
break;
}
prev = m;
m = m->next; /* move to next node */
}
if(!m) {
if(what == CURL_POLL_REMOVE) {
/* this happens a bit too often, libcurl fix perhaps? */
/* fprintf(stderr,
"%s: socket %d asked to be REMOVED but not present!\n",
__func__, s); */
}
else {
m = malloc(sizeof(struct monitor));
m->next = ev->list;
m->socket.fd = s;
m->socket.events = socketcb2poll(what);
m->socket.revents = 0;
ev->list = m;
infof(easy, "socket cb: socket %d ADDED as %s%s\n", s,
what&CURL_POLL_IN?"IN":"",
what&CURL_POLL_OUT?"OUT":"");
}
}
return 0;
}
/*
* events_setup()
*
* Do the multi handle setups that only event-based transfers need.
*/
static void events_setup(CURLM *multi, struct events *ev)
{
/* timer callback */
curl_multi_setopt(multi, CURLMOPT_TIMERFUNCTION, events_timer);
curl_multi_setopt(multi, CURLMOPT_TIMERDATA, ev);
/* socket callback */
curl_multi_setopt(multi, CURLMOPT_SOCKETFUNCTION, events_socket);
curl_multi_setopt(multi, CURLMOPT_SOCKETDATA, ev);
}
/* wait_or_timeout()
*
* waits for activity on any of the given sockets, or the timeout to trigger.
*/
static CURLcode wait_or_timeout(struct Curl_multi *multi, struct events *ev)
{
CURLM *multi;
CURLMcode mcode;
CURLcode code = CURLE_OK;
CURLMsg *msg;
bool done = FALSE;
int rc;
struct SessionHandle *data = easy;
CURLMcode mcode;
CURLcode rc = CURLE_OK;
while(!done) {
CURLMsg *msg;
struct monitor *m;
struct pollfd *f;
struct pollfd fds[4];
int numfds=0;
int pollrc;
int i;
struct timeval before;
struct timeval after;
/* populate the fds[] array */
for(m = ev->list, f=&fds[0]; m; m = m->next) {
f->fd = m->socket.fd;
f->events = m->socket.events;
f->revents = 0;
/* fprintf(stderr, "poll() %d check socket %d\n", numfds, f->fd); */
f++;
numfds++;
}
/* get the time stamp to use to figure out how long poll takes */
before = curlx_tvnow();
/* fprintf(stderr, "poll(), %d numfds\n", numfds); */
/* wait for activity or timeout */
pollrc = Curl_poll(fds, numfds, (int)ev->ms);
after = curlx_tvnow();
ev->msbump = FALSE; /* reset here */
if(0 == pollrc) {
/* timeout! */
ev->ms = 0;
/* fprintf(stderr, "call curl_multi_socket_action( TIMEOUT )\n"); */
mcode = curl_multi_socket_action(multi, CURL_SOCKET_TIMEOUT, 0,
&ev->running_handles);
}
else if(pollrc > 0) {
/* loop over the monitored sockets to see which ones had activity */
for(i = 0; i< numfds; i++) {
if(fds[i].revents) {
/* socket activity, tell libcurl */
int act = poll2cselect(fds[i].revents); /* convert */
infof(multi->easyp, "call curl_multi_socket_action( socket %d )\n",
fds[i].fd);
mcode = curl_multi_socket_action(multi, fds[i].fd, act,
&ev->running_handles);
}
}
if(!ev->msbump)
/* If nothing updated the timeout, we decrease it by the spent time.
* If it was updated, it has the new timeout time stored already.
*/
ev->ms += curlx_tvdiff(after, before);
}
if(mcode)
return CURLE_URL_MALFORMAT; /* TODO: return a proper error! */
/* we don't really care about the "msgs_in_queue" value returned in the
second argument */
msg = curl_multi_info_read(multi, &pollrc);
if(msg) {
rc = msg->data.result;
done = TRUE;
}
}
return rc;
}
/* easy_events()
*
* Runs a transfer in a blocking manner using the events-based API
*/
static CURLcode easy_events(CURLM *multi)
{
struct events evs= {2, FALSE, 0, NULL, 0};
/* if running event-based, do some further multi inits */
events_setup(multi, &evs);
return wait_or_timeout(multi, &evs);
}
#endif
static CURLcode easy_transfer(CURLM *multi)
{
bool done = FALSE;
CURLMcode mcode = CURLM_OK;
CURLcode code;
struct timeval before;
int without_fds = 0; /* count number of consecutive returns from
curl_multi_wait() without any filedescriptors */
struct timeval before;
SIGPIPE_VARIABLE(pipe_st);
if(!easy)
return CURLE_BAD_FUNCTION_ARGUMENT;
if(data->multi) {
failf(data, "easy handled already used in multi handle");
return CURLE_FAILED_INIT;
}
if(data->multi_easy)
multi = data->multi_easy;
else {
/* this multi handle will only ever have a single easy handled attached
to it, so make it use minimal hashes */
multi = Curl_multi_handle(1, 3);
if(!multi)
return CURLE_OUT_OF_MEMORY;
data->multi_easy = multi;
}
/* Copy the MAXCONNECTS option to the multi handle */
curl_multi_setopt(multi, CURLMOPT_MAXCONNECTS, data->set.maxconnects);
mcode = curl_multi_add_handle(multi, easy);
if(mcode) {
curl_multi_cleanup(multi);
if(mcode == CURLM_OUT_OF_MEMORY)
return CURLE_OUT_OF_MEMORY;
else
return CURLE_FAILED_INIT;
}
sigpipe_ignore(data, &pipe_st);
/* assign this after curl_multi_add_handle() since that function checks for
it and rejects this handle otherwise */
data->multi = multi;
while(!done && !mcode) {
int still_running;
@@ -556,13 +761,82 @@ CURLcode curl_easy_perform(CURL *easy)
/* only read 'still_running' if curl_multi_perform() return OK */
if((mcode == CURLM_OK) && !still_running) {
msg = curl_multi_info_read(multi, &rc);
int rc;
CURLMsg *msg = curl_multi_info_read(multi, &rc);
if(msg) {
code = msg->data.result;
done = TRUE;
}
}
}
return code;
}
/*
* easy_perform() is the external interface that performs a blocking
* transfer as previously setup.
*
* CONCEPT: This function creates a multi handle, adds the easy handle to it,
* runs curl_multi_perform() until the transfer is done, then detaches the
* easy handle, destroys the multi handle and returns the easy handle's return
* code.
*
* REALITY: it can't just create and destroy the multi handle that easily. It
* needs to keep it around since if this easy handle is used again by this
* function, the same multi handle must be re-used so that the same pools and
* caches can be used.
*
* DEBUG: if 'events' is set TRUE, this function will use a replacement engine
* instead of curl_multi_perform() and use curl_multi_socket_action().
*/
static CURLcode easy_perform(CURL *easy, bool events)
{
CURLM *multi;
CURLMcode mcode;
CURLcode code = CURLE_OK;
struct SessionHandle *data = easy;
SIGPIPE_VARIABLE(pipe_st);
if(!easy)
return CURLE_BAD_FUNCTION_ARGUMENT;
if(data->multi) {
failf(data, "easy handled already used in multi handle");
return CURLE_FAILED_INIT;
}
if(data->multi_easy)
multi = data->multi_easy;
else {
/* this multi handle will only ever have a single easy handled attached
to it, so make it use minimal hashes */
multi = Curl_multi_handle(1, 3);
if(!multi)
return CURLE_OUT_OF_MEMORY;
data->multi_easy = multi;
}
/* Copy the MAXCONNECTS option to the multi handle */
curl_multi_setopt(multi, CURLMOPT_MAXCONNECTS, data->set.maxconnects);
mcode = curl_multi_add_handle(multi, easy);
if(mcode) {
curl_multi_cleanup(multi);
if(mcode == CURLM_OUT_OF_MEMORY)
return CURLE_OUT_OF_MEMORY;
else
return CURLE_FAILED_INIT;
}
sigpipe_ignore(data, &pipe_st);
/* assign this after curl_multi_add_handle() since that function checks for
it and rejects this handle otherwise */
data->multi = multi;
/* run the transfer */
code = events ? easy_events(multi) : easy_transfer(multi);
/* ignoring the return code isn't nice, but atm we can't really handle
a failure here, room for future improvement! */
@@ -574,6 +848,28 @@ CURLcode curl_easy_perform(CURL *easy)
return code;
}
/*
* curl_easy_perform() is the external interface that performs a blocking
* transfer as previously setup.
*/
CURLcode curl_easy_perform(CURL *easy)
{
return easy_perform(easy, FALSE);
}
#ifdef CURLDEBUG
/*
* curl_easy_perform_ev() is the external interface that performs a blocking
* transfer using the event-based API internally.
*/
CURLcode curl_easy_perform_ev(CURL *easy)
{
return easy_perform(easy, TRUE);
}
#endif
/*
* curl_easy_cleanup() is the external interface to cleaning/freeing the given
* easy handle.