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authorRich Felker <dalias@aerifal.cx>2011-09-09 01:07:38 -0400
committerRich Felker <dalias@aerifal.cx>2011-09-09 01:07:38 -0400
commitb4de6f93aed733b8fc8d103e5ced69ebe7d659e6 (patch)
tree33664a468c80b6b37a079d7d9bdbadf5adf4f93c /src/aio/aio_readwrite.c
parent96cea94ad258be262ecf15b33d13cf775e59720d (diff)
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implement POSIX asynchronous io
some features are not yet supported, and only minimal testing has been performed. should be considered experimental at this point.
Diffstat (limited to 'src/aio/aio_readwrite.c')
-rw-r--r--src/aio/aio_readwrite.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/src/aio/aio_readwrite.c b/src/aio/aio_readwrite.c
new file mode 100644
index 00000000..27168f25
--- /dev/null
+++ b/src/aio/aio_readwrite.c
@@ -0,0 +1,104 @@
+#include <aio.h>
+#include <fcntl.h>
+#include "pthread_impl.h"
+
+static void dummy(void)
+{
+}
+
+weak_alias(dummy, __aio_wake);
+
+static void notify_signal(struct sigevent *sev)
+{
+ siginfo_t si = {
+ .si_signo = sev->sigev_signo,
+ .si_value = sev->sigev_value,
+ .si_code = SI_ASYNCIO,
+ .si_pid = __pthread_self()->pid,
+ .si_uid = getuid()
+ };
+ __syscall(SYS_rt_sigqueueinfo, si.si_pid, si.si_signo, &si);
+}
+
+static void *io_thread(void *p)
+{
+ struct aiocb *cb = p;
+ int fd = cb->aio_filedes;
+ void *buf = (void *)cb->aio_buf;
+ size_t len = cb->aio_nbytes;
+ off_t off = cb->aio_offset;
+ int op = cb->aio_lio_opcode;
+ struct sigevent sev = cb->aio_sigevent;
+ ssize_t ret;
+
+ if (op == LIO_WRITE) {
+ if ( (fcntl(fd, F_GETFL) & O_APPEND)
+ ||((ret = pwrite(fd, buf, len, off))<0 && errno==ESPIPE) )
+ ret = write(fd, buf, len);
+ } else if (op == LIO_READ) {
+ if ( (ret = pread(fd, buf, len, off))<0 && errno==ESPIPE )
+ ret = read(fd, buf, len);
+ } else {
+ ret = 0;
+ }
+ cb->__ret = ret;
+
+ if (ret < 0) a_store(&cb->__err, errno);
+ else a_store(&cb->__err, 0);
+
+ __aio_wake();
+
+ switch (cb->aio_sigevent.sigev_notify) {
+ case SIGEV_SIGNAL:
+ notify_signal(&sev);
+ break;
+ case SIGEV_THREAD:
+ sev.sigev_notify_function(sev.sigev_value);
+ break;
+ }
+
+ return 0;
+}
+
+static int new_req(struct aiocb *cb)
+{
+ int ret = 0;
+ pthread_attr_t a;
+ sigset_t set;
+ pthread_t td;
+
+ if (cb->aio_sigevent.sigev_notify == SIGEV_THREAD) {
+ if (cb->aio_sigevent.sigev_notify_attributes)
+ a = *cb->aio_sigevent.sigev_notify_attributes;
+ else
+ pthread_attr_init(&a);
+ } else {
+ pthread_attr_init(&a);
+ pthread_attr_setstacksize(&a, PAGE_SIZE);
+ pthread_attr_setguardsize(&a, 0);
+ }
+ pthread_attr_setdetachstate(&a, PTHREAD_CREATE_DETACHED);
+ sigfillset(&set);
+ pthread_sigmask(SIG_BLOCK, &set, &set);
+ cb->__err = EINPROGRESS;
+ if (pthread_create(&td, &a, io_thread, cb)) {
+ errno = EAGAIN;
+ ret = -1;
+ }
+ pthread_sigmask(SIG_SETMASK, &set, 0);
+ cb->__td = td;
+
+ return ret;
+}
+
+ssize_t aio_read(struct aiocb *cb)
+{
+ cb->aio_lio_opcode = LIO_READ;
+ return new_req(cb);
+}
+
+ssize_t aio_write(struct aiocb *cb)
+{
+ cb->aio_lio_opcode = LIO_WRITE;
+ return new_req(cb);
+}