port_buffer_size_etc() was horribly broken in a lot of ways, it even read
the info from the wrong end of the queue. find_port() did not return the correct error codes. write_port_etc() checked incorrectly for a deleted semaphore. B_WOULD_BLOCK would let various functions print out a warning for no reason (the comments in the code actually didn't fit to the implementation). "total_count" was counting the number of messages written, not those that have been read (as the BeBook says). Thanks to Bill Hayden who reported a lot of these. Added TRACE macro and moved some of the dprintf()s to that. Added/fixed some comments. git-svn-id: file:///srv/svn/repos/haiku/trunk/current@6901 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler
parent
75a52c6151
commit
7fb4c29b80
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@ -24,6 +24,14 @@
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#include <stdlib.h>
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//#define TRACE_PORTS
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#ifdef TRACE_PORTS
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# define TRACE(x) dprintf x
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#else
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# define TRACE(x)
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#endif
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struct port_msg {
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int msg_code;
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cbuf *data_cbuf;
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@ -377,14 +385,14 @@ delete_port(port_id id)
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port_id
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find_port(const char *name)
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{
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port_id portFound = B_BAD_PORT_ID;
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port_id portFound = B_NAME_NOT_FOUND;
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cpu_status state;
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int i;
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if (ports_active == false)
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return B_BAD_PORT_ID;
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return B_NAME_NOT_FOUND;
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if (name == NULL)
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return B_BAD_PORT_ID;
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return B_BAD_VALUE;
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// Since we have to check every single port, and we don't
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// care if it goes away at any point, we're only grabbing
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@ -415,12 +423,20 @@ find_port(const char *name)
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static void
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fill_port_info(struct port_entry *port, port_info *info, size_t size)
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{
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int32 count;
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info->port = port->id;
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info->team = port->owner;
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info->capacity = port->capacity;
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info->total_count = gPorts->total_count;
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strlcpy(info->name, gPorts->name, B_OS_NAME_LENGTH);
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get_sem_count(port->read_sem, &info->queue_count);
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get_sem_count(port->read_sem, &count);
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if (count < 0)
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count = 0;
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info->queue_count = count;
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info->total_count = port->total_count;
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strlcpy(info->name, port->name, B_OS_NAME_LENGTH);
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}
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@ -515,12 +531,13 @@ port_buffer_size(port_id id)
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ssize_t
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port_buffer_size_etc(port_id id, uint32 flags, bigtime_t timeout)
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{
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cpu_status state;
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sem_id cachedSem;
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status_t status;
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ssize_t size;
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int slot;
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int res;
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int t;
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int len;
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int state;
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int tail;
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if (!ports_active || id < 0)
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return B_BAD_PORT_ID;
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@ -532,9 +549,12 @@ port_buffer_size_etc(port_id id, uint32 flags, bigtime_t timeout)
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if (gPorts[slot].id != id) {
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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dprintf("get_port_info: invalid port_id %ld\n", id);
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TRACE(("get_buffer_size_etc: invalid port_id %ld\n", id));
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return B_BAD_PORT_ID;
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}
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cachedSem = gPorts[slot].read_sem;
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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@ -544,37 +564,41 @@ port_buffer_size_etc(port_id id, uint32 flags, bigtime_t timeout)
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// XXX - is it a race condition to acquire a sem just after we
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// unlocked the port ?
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// XXX: call an acquire_sem which does the release lock, restore int & block the right way
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res = acquire_sem_etc(gPorts[slot].read_sem, 1, flags & (B_TIMEOUT | B_CAN_INTERRUPT), timeout);
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status = acquire_sem_etc(cachedSem, 1, flags, timeout);
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GRAB_PORT_LOCK(gPorts[slot]);
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if (res == B_BAD_SEM_ID) {
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if (status == B_BAD_SEM_ID) {
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// somebody deleted the port
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RELEASE_PORT_LOCK(gPorts[slot]);
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return B_BAD_PORT_ID;
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}
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if (res == B_TIMED_OUT) {
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if (status == B_TIMED_OUT || B_WOULD_BLOCK)
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return status;
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state = disable_interrupts();
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GRAB_PORT_LOCK(gPorts[slot]);
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if (gPorts[slot].id != id) {
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// the port is no longer there
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RELEASE_PORT_LOCK(gPorts[slot]);
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return B_TIMED_OUT;
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restore_interrupts(state);
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return B_BAD_PORT_ID;
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}
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// once message arrived, read data's length
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// determine tail
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// read data's head length
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t = gPorts[slot].head;
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if (t < 0)
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// determine tail & get the length of the message
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tail = gPorts[slot].tail;
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if (tail < 0)
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panic("port %ld: tail < 0", gPorts[slot].id);
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if (t > gPorts[slot].capacity)
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if (tail > gPorts[slot].capacity)
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panic("port %ld: tail > cap %ld", gPorts[slot].id, gPorts[slot].capacity);
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len = gPorts[slot].msg_queue[t].data_len;
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// restore readsem
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release_sem(gPorts[slot].read_sem);
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size = gPorts[slot].msg_queue[tail].data_len;
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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// restore read_sem, as we haven't read from the port
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release_sem(cachedSem);
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// return length of item at end of queue
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return len;
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return size;
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}
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@ -585,9 +609,8 @@ port_count(port_id id)
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int state;
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int32 count;
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if (ports_active == false)
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return B_BAD_PORT_ID;
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if (id < 0)
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if (ports_active == false
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|| id < 0)
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return B_BAD_PORT_ID;
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slot = id % MAX_PORTS;
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@ -598,10 +621,10 @@ port_count(port_id id)
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if (gPorts[slot].id != id) {
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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dprintf("port_count: invalid port_id %ld\n", id);
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TRACE(("port_count: invalid port_id %ld\n", id));
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return B_BAD_PORT_ID;
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}
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get_sem_count(gPorts[slot].read_sem, &count);
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// do not return negative numbers
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if (count < 0)
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@ -626,15 +649,15 @@ status_t
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read_port_etc(port_id id, int32 *msgCode, void *msgBuffer, size_t bufferSize,
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uint32 flags, bigtime_t timeout)
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{
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int slot;
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int state;
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sem_id cached_semid;
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cpu_status state;
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sem_id cachedSem;
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size_t size;
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status_t status;
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int t;
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int tail;
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cbuf *msgStore;
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int32 code;
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bool userCopy = (flags & PORT_FLAG_USE_USER_MEMCPY) > 0;
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int slot;
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if (ports_active == false
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|| id < 0)
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@ -658,7 +681,7 @@ read_port_etc(port_id id, int32 *msgCode, void *msgBuffer, size_t bufferSize,
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return B_BAD_PORT_ID;
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}
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// store sem_id in local variable
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cached_semid = gPorts[slot].read_sem;
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cachedSem = gPorts[slot].read_sem;
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// unlock port && enable ints/
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RELEASE_PORT_LOCK(gPorts[slot]);
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@ -666,23 +689,21 @@ read_port_etc(port_id id, int32 *msgCode, void *msgBuffer, size_t bufferSize,
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// XXX -> possible race condition if port gets deleted (->sem deleted too), therefore
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// sem_id is cached in local variable up here
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status = acquire_sem_etc(cached_semid, 1, flags, timeout);
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status = acquire_sem_etc(cachedSem, 1, flags, timeout);
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// get 1 entry from the queue, block if needed
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// XXX: possible race condition if port read by two threads...
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// both threads will read in 2 different slots allocated above, simultaneously
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// slot is a thread-local variable
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if (status == B_BAD_SEM_ID || status == EINTR) {
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if (status == B_BAD_SEM_ID || status == B_INTERRUPTED) {
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/* somebody deleted the port or the sem went away */
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return B_BAD_PORT_ID;
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}
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if (status == B_TIMED_OUT) {
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// timed out, or, if timeout=0, 'would block'
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return B_BAD_PORT_ID;
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}
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if (status == B_TIMED_OUT || status == B_WOULD_BLOCK)
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return status;
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if (status != B_NO_ERROR) {
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dprintf("write_port_etc: unknown error %ld\n", status);
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@ -692,24 +713,25 @@ read_port_etc(port_id id, int32 *msgCode, void *msgBuffer, size_t bufferSize,
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state = disable_interrupts();
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GRAB_PORT_LOCK(gPorts[slot]);
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t = gPorts[slot].tail;
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if (t < 0)
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tail = gPorts[slot].tail;
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if (tail < 0)
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panic("port %ld: tail < 0", gPorts[slot].id);
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if (t > gPorts[slot].capacity)
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if (tail > gPorts[slot].capacity)
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panic("port %ld: tail > cap %ld", gPorts[slot].id, gPorts[slot].capacity);
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gPorts[slot].tail = (gPorts[slot].tail + 1) % gPorts[slot].capacity;
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gPorts[slot].total_count++;
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msgStore = gPorts[slot].msg_queue[t].data_cbuf;
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code = gPorts[slot].msg_queue[t].msg_code;
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msgStore = gPorts[slot].msg_queue[tail].data_cbuf;
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code = gPorts[slot].msg_queue[tail].msg_code;
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// mark queue entry unused
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gPorts[slot].msg_queue[t].data_cbuf = NULL;
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gPorts[slot].msg_queue[tail].data_cbuf = NULL;
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// check output buffer size
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size = min(bufferSize, gPorts[slot].msg_queue[t].data_len);
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size = min(bufferSize, gPorts[slot].msg_queue[tail].data_len);
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cached_semid = gPorts[slot].write_sem;
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cachedSem = gPorts[slot].write_sem;
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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@ -721,7 +743,7 @@ read_port_etc(port_id id, int32 *msgCode, void *msgBuffer, size_t bufferSize,
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if ((status = cbuf_user_memcpy_from_chain(msgBuffer, msgStore, 0, size) < B_OK)) {
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// leave the port intact, for other threads that might not crash
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cbuf_free_chain(msgStore);
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release_sem(cached_semid);
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release_sem(cachedSem);
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return status;
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}
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} else
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@ -731,7 +753,7 @@ read_port_etc(port_id id, int32 *msgCode, void *msgBuffer, size_t bufferSize,
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cbuf_free_chain(msgStore);
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// make one spot in queue available again for write
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release_sem(cached_semid);
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release_sem(cachedSem);
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return size;
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}
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@ -749,10 +771,10 @@ write_port_etc(port_id id, int32 msgCode, const void *msgBuffer,
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size_t bufferSize, uint32 flags, bigtime_t timeout)
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{
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int slot;
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int state;
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cpu_status state;
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status_t status;
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sem_id cached_semid;
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int h;
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sem_id cachedSem;
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int head;
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cbuf *msgStore;
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bool userCopy = (flags & PORT_FLAG_USE_USER_MEMCPY) > 0;
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@ -773,42 +795,40 @@ write_port_etc(port_id id, int32 msgCode, const void *msgBuffer,
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if (gPorts[slot].id != id) {
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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dprintf("write_port_etc: invalid port_id %ld\n", id);
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TRACE(("write_port_etc: invalid port_id %ld\n", id));
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return B_BAD_PORT_ID;
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}
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if (gPorts[slot].closed) {
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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dprintf("write_port_etc: port %ld closed\n", id);
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TRACE(("write_port_etc: port %ld closed\n", id));
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return B_BAD_PORT_ID;
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}
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// store sem_id in local variable
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cached_semid = gPorts[slot].write_sem;
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cachedSem = gPorts[slot].write_sem;
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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// XXX -> possible race condition if port gets deleted (->sem deleted too),
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// and queue is full therefore sem_id is cached in local variable up here
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status = acquire_sem_etc(cached_semid, 1, flags, timeout);
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status = acquire_sem_etc(cachedSem, 1, flags, timeout);
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// get 1 entry from the queue, block if needed
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// XXX: possible race condition if port written by two threads...
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// both threads will write in 2 different slots allocated above, simultaneously
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// slot is a thread-local variable
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if (status == B_BAD_PORT_ID || status == B_INTERRUPTED) {
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if (status == B_BAD_SEM_ID || status == B_INTERRUPTED) {
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/* somebody deleted the port or the sem while we were waiting */
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return B_BAD_PORT_ID;
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}
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if (status == B_TIMED_OUT) {
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// timed out, or, if timeout = 0, 'would block'
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return B_TIMED_OUT;
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}
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if (status == B_TIMED_OUT || status == B_WOULD_BLOCK)
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return status;
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if (status != B_NO_ERROR) {
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dprintf("write_port_etc: unknown error %ld\n", status);
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@ -836,26 +856,25 @@ write_port_etc(port_id id, int32 msgCode, const void *msgBuffer,
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state = disable_interrupts();
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GRAB_PORT_LOCK(gPorts[slot]);
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h = gPorts[slot].head;
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if (h < 0)
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head = gPorts[slot].head;
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if (head < 0)
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panic("port %ld: head < 0", gPorts[slot].id);
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if (h >= gPorts[slot].capacity)
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if (head >= gPorts[slot].capacity)
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panic("port %ld: head > cap %ld", gPorts[slot].id, gPorts[slot].capacity);
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gPorts[slot].msg_queue[h].msg_code = msgCode;
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gPorts[slot].msg_queue[h].data_cbuf = msgStore;
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gPorts[slot].msg_queue[h].data_len = bufferSize;
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gPorts[slot].msg_queue[head].msg_code = msgCode;
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gPorts[slot].msg_queue[head].data_cbuf = msgStore;
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gPorts[slot].msg_queue[head].data_len = bufferSize;
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gPorts[slot].head = (gPorts[slot].head + 1) % gPorts[slot].capacity;
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gPorts[slot].total_count++;
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// store sem_id in local variable
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cached_semid = gPorts[slot].read_sem;
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cachedSem = gPorts[slot].read_sem;
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RELEASE_PORT_LOCK(gPorts[slot]);
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restore_interrupts(state);
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// release sem, allowing read (might reschedule)
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release_sem(cached_semid);
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release_sem(cachedSem);
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return B_NO_ERROR;
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}
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@ -894,13 +913,15 @@ set_port_owner(port_id id, team_id team)
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}
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/** this function cycles through the gPorts table, deleting all
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* the gPorts that are owned by the passed team_id
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/** this function cycles through the ports table, deleting all
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* the ports that are owned by the passed team_id
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*/
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int
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delete_owned_ports(team_id owner)
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{
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// ToDo: investigate maintaining a list of ports in the team
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// to make this simpler and more efficient.
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int state;
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int i;
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int count = 0;
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@ -912,7 +933,7 @@ delete_owned_ports(team_id owner)
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GRAB_PORT_LIST_LOCK();
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for (i = 0; i < MAX_PORTS; i++) {
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if(gPorts[i].id != -1 && gPorts[i].owner == owner) {
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if (gPorts[i].id != -1 && gPorts[i].owner == owner) {
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port_id id = gPorts[i].id;
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RELEASE_PORT_LIST_LOCK();
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