From 9e7df9aa6d81f0abbabb03a2346d80eb5d375f81 Mon Sep 17 00:00:00 2001 From: Werner Koch Date: Thu, 25 Apr 2013 12:00:16 +0100 Subject: [PATCH] w32: Change the way the I/O threads are cleaned up. * src/w32-io.c (reader_context_s, create_reader) (writer_context_s, create_writer): Rename STOPPED to CLOSE_EV. (reader, writer): Remove setting of STOPPED. Wait for CLOSE_EV and then release the context. (destroy_reader, destroy_writer): Do not wait but set the CLOSE_EV. (kill_reader, kill_writer): Remove. (_gpgme_io_close): Add code from kill_reader and kill_writer. -- The old code was prone to deadlocks which were actually exhibited at Kleopatra startup. The new code is much more straightforward and easier to understand. The reason for the complex old code was probably due to our former idea to allow re-use of the I/O threads. However we have long given up on this. --- src/w32-io.c | 163 +++++++++++++++++++++++---------------------------- 1 file changed, 73 insertions(+), 90 deletions(-) diff --git a/src/w32-io.c b/src/w32-io.c index 776e3792..d896ec0e 100644 --- a/src/w32-io.c +++ b/src/w32-io.c @@ -162,7 +162,9 @@ struct reader_context_s HANDLE have_data_ev; /* This is automatically reset. */ HANDLE have_space_ev; - HANDLE stopped; + /* This is manually reset but actually only triggered once. */ + HANDLE close_ev; + size_t readpos, writepos; char buffer[READBUF_SIZE]; }; @@ -194,7 +196,7 @@ struct writer_context_s /* This is manually reset. */ HANDLE have_data; HANDLE is_empty; - HANDLE stopped; + HANDLE close_ev; size_t nbytes; char buffer[WRITEBUF_SIZE]; }; @@ -383,9 +385,18 @@ reader (void *arg) } /* Indicate that we have an error or EOF. */ if (!SetEvent (ctx->have_data_ev)) - TRACE_LOG2 ("SetEvent (0x%x) failed: ec=%d", ctx->have_data_ev, - (int) GetLastError ()); - SetEvent (ctx->stopped); + TRACE_LOG2 ("SetEvent (0x%x) failed: ec=%d", ctx->have_data_ev, + (int) GetLastError ()); + + TRACE_LOG ("waiting for close"); + WaitForSingleObject (ctx->close_ev, INFINITE); + + CloseHandle (ctx->close_ev); + CloseHandle (ctx->have_data_ev); + CloseHandle (ctx->have_space_ev); + CloseHandle (ctx->thread_hd); + DESTROY_LOCK (ctx->mutex); + free (ctx); return TRACE_SUC (); } @@ -427,16 +438,16 @@ create_reader (int fd) if (ctx->have_data_ev) ctx->have_space_ev = CreateEvent (&sec_attr, FALSE, TRUE, NULL); if (ctx->have_space_ev) - ctx->stopped = CreateEvent (&sec_attr, TRUE, FALSE, NULL); - if (!ctx->have_data_ev || !ctx->have_space_ev || !ctx->stopped) + ctx->close_ev = CreateEvent (&sec_attr, TRUE, FALSE, NULL); + if (!ctx->have_data_ev || !ctx->have_space_ev || !ctx->close_ev) { TRACE_LOG1 ("CreateEvent failed: ec=%d", (int) GetLastError ()); if (ctx->have_data_ev) CloseHandle (ctx->have_data_ev); if (ctx->have_space_ev) CloseHandle (ctx->have_space_ev); - if (ctx->stopped) - CloseHandle (ctx->stopped); + if (ctx->close_ev) + CloseHandle (ctx->close_ev); free (ctx); /* FIXME: Translate the error code. */ TRACE_SYSERR (EIO); @@ -461,8 +472,8 @@ create_reader (int fd) CloseHandle (ctx->have_data_ev); if (ctx->have_space_ev) CloseHandle (ctx->have_space_ev); - if (ctx->stopped) - CloseHandle (ctx->stopped); + if (ctx->close_ev) + CloseHandle (ctx->close_ev); free (ctx); TRACE_SYSERR (EIO); return NULL; @@ -480,6 +491,9 @@ create_reader (int fd) } +/* Prepare destruction of the reader thread for CTX. Returns 0 if a + call to this function is sufficient and destroy_reader_finish shall + not be called. */ static void destroy_reader (struct reader_context_s *ctx) { @@ -531,24 +545,12 @@ destroy_reader (struct reader_context_s *ctx) ctx->file_sock, (int) WSAGetLastError ()); } - TRACE1 (DEBUG_SYSIO, "gpgme:destroy_reader", ctx->file_hd, - "waiting for termination of thread %p", ctx->thread_hd); - WaitForSingleObject (ctx->stopped, INFINITE); - TRACE1 (DEBUG_SYSIO, "gpgme:destroy_reader", ctx->file_hd, - "thread %p has terminated", ctx->thread_hd); - - if (ctx->stopped) - CloseHandle (ctx->stopped); - if (ctx->have_data_ev) - CloseHandle (ctx->have_data_ev); - if (ctx->have_space_ev) - CloseHandle (ctx->have_space_ev); - CloseHandle (ctx->thread_hd); - DESTROY_LOCK (ctx->mutex); - free (ctx); + /* After setting this event CTX is void. */ + SetEvent (ctx->close_ev); } + /* Find a reader context or create a new one. Note that the reader context will last until a _gpgme_io_close. */ static struct reader_context_s * @@ -585,26 +587,6 @@ find_reader (int fd, int start_it) } -static void -kill_reader (int fd) -{ - int i; - - LOCK (reader_table_lock); - for (i = 0; i < reader_table_size; i++) - { - if (reader_table[i].used && reader_table[i].fd == fd) - { - destroy_reader (reader_table[i].context); - reader_table[i].context = NULL; - reader_table[i].used = 0; - break; - } - } - UNLOCK (reader_table_lock); -} - - int _gpgme_io_read (int fd, void *buffer, size_t count) { @@ -774,7 +756,16 @@ writer (void *arg) /* Indicate that we have an error. */ if (!SetEvent (ctx->is_empty)) TRACE_LOG1 ("SetEvent failed: ec=%d", (int) GetLastError ()); - SetEvent (ctx->stopped); + + TRACE_LOG ("waiting for close"); + WaitForSingleObject (ctx->close_ev, INFINITE); + + CloseHandle (ctx->close_ev); + CloseHandle (ctx->have_data); + CloseHandle (ctx->is_empty); + CloseHandle (ctx->thread_hd); + DESTROY_LOCK (ctx->mutex); + free (ctx); return TRACE_SUC (); } @@ -816,16 +807,16 @@ create_writer (int fd) if (ctx->have_data) ctx->is_empty = CreateEvent (&sec_attr, TRUE, TRUE, NULL); if (ctx->is_empty) - ctx->stopped = CreateEvent (&sec_attr, TRUE, FALSE, NULL); - if (!ctx->have_data || !ctx->is_empty || !ctx->stopped) + ctx->close_ev = CreateEvent (&sec_attr, TRUE, FALSE, NULL); + if (!ctx->have_data || !ctx->is_empty || !ctx->close_ev) { TRACE_LOG1 ("CreateEvent failed: ec=%d", (int) GetLastError ()); if (ctx->have_data) CloseHandle (ctx->have_data); if (ctx->is_empty) CloseHandle (ctx->is_empty); - if (ctx->stopped) - CloseHandle (ctx->stopped); + if (ctx->close_ev) + CloseHandle (ctx->close_ev); free (ctx); /* FIXME: Translate the error code. */ TRACE_SYSERR (EIO); @@ -850,8 +841,8 @@ create_writer (int fd) CloseHandle (ctx->have_data); if (ctx->is_empty) CloseHandle (ctx->is_empty); - if (ctx->stopped) - CloseHandle (ctx->stopped); + if (ctx->close_ev) + CloseHandle (ctx->close_ev); free (ctx); TRACE_SYSERR (EIO); return NULL; @@ -868,6 +859,7 @@ create_writer (int fd) return ctx; } + static void destroy_writer (struct writer_context_s *ctx) { @@ -897,21 +889,8 @@ destroy_writer (struct writer_context_s *ctx) } #endif - TRACE1 (DEBUG_SYSIO, "gpgme:destroy_writer", ctx->file_hd, - "waiting for termination of thread %p", ctx->thread_hd); - WaitForSingleObject (ctx->stopped, INFINITE); - TRACE1 (DEBUG_SYSIO, "gpgme:destroy_writer", ctx->file_hd, - "thread %p has terminated", ctx->thread_hd); - - if (ctx->stopped) - CloseHandle (ctx->stopped); - if (ctx->have_data) - CloseHandle (ctx->have_data); - if (ctx->is_empty) - CloseHandle (ctx->is_empty); - CloseHandle (ctx->thread_hd); - DESTROY_LOCK (ctx->mutex); - free (ctx); + /* After setting this event CTX is void. */ + SetEvent (ctx->close_ev); } @@ -951,26 +930,6 @@ find_writer (int fd, int start_it) } -static void -kill_writer (int fd) -{ - int i; - - LOCK (writer_table_lock); - for (i = 0; i < writer_table_size; i++) - { - if (writer_table[i].used && writer_table[i].fd == fd) - { - destroy_writer (writer_table[i].context); - writer_table[i].context = NULL; - writer_table[i].used = 0; - break; - } - } - UNLOCK (writer_table_lock); -} - - int _gpgme_io_write (int fd, const void *buffer, size_t count) { @@ -1195,8 +1154,32 @@ _gpgme_io_close (int fd) fd, fd_table[fd].handle, fd_table[fd].socket, fd_table[fd].dup_from); - kill_reader (fd); - kill_writer (fd); + LOCK (reader_table_lock); + for (i = 0; i < reader_table_size; i++) + { + if (reader_table[i].used && reader_table[i].fd == fd) + { + destroy_reader (reader_table[i].context); + reader_table[i].context = NULL; + reader_table[i].used = 0; + break; + } + } + UNLOCK (reader_table_lock); + + LOCK (writer_table_lock); + for (i = 0; i < writer_table_size; i++) + { + if (writer_table[i].used && writer_table[i].fd == fd) + { + destroy_writer (writer_table[i].context); + writer_table[i].context = NULL; + writer_table[i].used = 0; + break; + } + } + UNLOCK (writer_table_lock); + LOCK (notify_table_lock); for (i = 0; i < DIM (notify_table); i++) {