[tarantool-patches] [PATCH] Fix lua socket polling in case of a spurious wakeup
Georgy Kirichenko
georgy at tarantool.org
Thu Aug 2 18:44:53 MSK 2018
socket_writable/socket_readable handles socket.iowait spurious wakeup
until event is happened or timeout is exceeded.
Fixes #3344
---
Issue: https://github.com/tarantool/tarantool/issues/3344
Branch: https://github.com/tarantool/tarantool/tree/g.kirichenko/gh-3344-socket-io-spurios-wakeup
src/lua/socket.lua | 67 ++++++++++++++++++++------------------
test/app/socket.result | 70 ++++++++++++++++++++++++++++++++++++++++
test/app/socket.test.lua | 29 +++++++++++++++++
3 files changed, 135 insertions(+), 31 deletions(-)
diff --git a/src/lua/socket.lua b/src/lua/socket.lua
index 06306eae2..9fcaee0e8 100644
--- a/src/lua/socket.lua
+++ b/src/lua/socket.lua
@@ -328,12 +328,18 @@ local function do_wait(self, what, timeout)
self._errno = nil
timeout = timeout or TIMEOUT_INFINITY
- local res = internal.iowait(fd, what, timeout)
- if res == 0 then
- self._errno = boxerrno.ETIMEDOUT
- return 0
+ local deadline = fiber.clock() + timeout
+ local events
+
+ while fiber.clock() <= deadline do
+ events = internal.iowait(fd, what, deadline - fiber.clock())
+ fiber.testcancel()
+ if events ~= 0 and events ~= '' then
+ return events
+ end
end
- return res
+ self._errno = boxerrno.ETIMEDOUT
+ return events
end
local function socket_readable(self, timeout)
@@ -662,7 +668,7 @@ local function read(self, limit, timeout, check, ...)
return data
end
- while timeout > 0 do
+ while timeout >= 0 do
local started = fiber.clock()
assert(rbuf:size() < limit)
@@ -689,15 +695,9 @@ local function read(self, limit, timeout, check, ...)
return nil
end
- if not socket_readable(self, timeout) then
- return nil
- end
- if timeout <= 0 then
- break
- end
+ socket_readable(self, timeout)
timeout = timeout - ( fiber.clock() - started )
end
- self._errno = boxerrno.ETIMEDOUT
return nil
end
@@ -736,7 +736,7 @@ local function socket_write(self, octets, timeout)
end
local started = fiber.clock()
- while true do
+ while timeout >= 0 do
local written = syswrite(self, p, e - p)
if written == 0 then
return p - s -- eof
@@ -750,11 +750,10 @@ local function socket_write(self, octets, timeout)
return nil
end
+ socket_writable(self, timeout)
timeout = timeout - (fiber.clock() - started)
- if timeout <= 0 or not socket_writable(self, timeout) then
- break
- end
end
+ return p - s
end
local function socket_send(self, octets, flags)
@@ -935,16 +934,19 @@ local function socket_tcp_connect(s, address, port, timeout)
-- Wait until the connection is established or ultimately fails.
-- In either condition the socket becomes writable. To tell these
-- conditions appart SO_ERROR must be consulted (man connect).
- if socket_writable(s, timeout) then
- s._errno = socket_getsockopt(s, 'SOL_SOCKET', 'SO_ERROR')
- else
- s._errno = boxerrno.ETIMEDOUT
- end
- if s._errno ~= 0 then
- return nil
+ local deadline = timeout + fiber.clock()
+ while deadline - fiber.clock() >= 0 do
+ if socket_writable(s, deadline - fiber.clock()) then
+ s._errno = socket_getsockopt(s, 'SOL_SOCKET', 'SO_ERROR')
+ if s._errno == 0 then
+ return true
+ else
+ return nil
+ end
+ end
end
- -- Connected
- return true
+ s._errno = boxerrno.ETIMEDOUT
+ return nil
end
local function tcp_connect(host, port, timeout)
@@ -1005,7 +1007,8 @@ end
local function tcp_server_loop(server, s, addr)
fiber.name(format("%s/%s:%s", server.name, addr.host, addr.port), {truncate = true})
log.info("started")
- while socket_readable(s) do
+ while true do
+ socket_readable(s)
local sc, from = socket_accept(s)
if sc == nil then
local errno = s._errno
@@ -1325,7 +1328,8 @@ end
local function lsocket_tcp_accept(self)
check_socket(self)
local deadline = fiber.clock() + (self.timeout or TIMEOUT_INFINITY)
- repeat
+ while deadline - fiber.clock() >= 0 do
+ socket_readable(self, deadline - fiber.clock())
local client = socket_accept(self)
if client then
setmetatable(client, lsocket_tcp_client_mt)
@@ -1335,7 +1339,7 @@ local function lsocket_tcp_accept(self)
if not errno_is_transient[errno] then
break
end
- until not socket_readable(self, deadline - fiber.clock())
+ end
return nil, socket_error(self)
end
@@ -1390,7 +1394,8 @@ local function lsocket_tcp_receive(self, pattern, prefix)
elseif pattern == "*a" then
local result = { prefix }
local deadline = fiber.clock() + (self.timeout or TIMEOUT_INFINITY)
- repeat
+ while deadline - fiber.clock() >= 0 do
+ socket_readable(self, deadline - fiber.clock())
local data = socket_sysread(self)
if data == nil then
if not errno_is_transient[self._errno] then
@@ -1401,7 +1406,7 @@ local function lsocket_tcp_receive(self, pattern, prefix)
else
table.insert(result, data)
end
- until not socket_readable(self, deadline - fiber.clock())
+ end
if #result == 1 then
return nil, 'closed', table.concat(result)
end
diff --git a/test/app/socket.result b/test/app/socket.result
index b4d4a9a78..d6f6762e0 100644
--- a/test/app/socket.result
+++ b/test/app/socket.result
@@ -2230,6 +2230,76 @@ s:close()
---
- 1
...
+--gh-3344 connection should not fail is there is a spurious wakeup for io fiber
+test_run:cmd("setopt delimiter ';'")
+---
+- true
+...
+echo_fiber = nil
+server = socket.tcp_server('localhost', 0, { handler = function(s)
+ echo_fiber = fiber.self()
+ while true do
+ local b = s:read(1, 0.1)
+ if b ~= nil then
+ s:write(b)
+ end
+ end
+end, name = 'echoserv'});
+---
+...
+test_run:cmd("setopt delimiter ''");
+---
+- true
+...
+addr = server:name()
+---
+...
+client = socket.tcp_connect(addr.host, addr.port)
+---
+...
+echo_fiber ~= nil
+---
+- true
+...
+client:write('hello')
+---
+- 5
+...
+client:read(5, 0.1) == 'hello'
+---
+- true
+...
+-- send spurious wakeup
+fiber.wakeup(echo_fiber)
+---
+...
+fiber.sleep(0)
+---
+...
+client:write('world')
+---
+- 5
+...
+client:read(5, 0.1) == 'world'
+---
+- true
+...
+-- cancel fiber
+fiber.cancel(echo_fiber)
+---
+...
+client:write('!')
+---
+- 1
+...
+client:read(1, 0.1) == ''
+---
+- true
+...
+server:close()
+---
+- true
+...
test_run:cmd("clear filter")
---
- true
diff --git a/test/app/socket.test.lua b/test/app/socket.test.lua
index f6539438b..4e44b7ac0 100644
--- a/test/app/socket.test.lua
+++ b/test/app/socket.test.lua
@@ -736,4 +736,33 @@ sc:connect(host, port)
sc:close()
s:close()
+--gh-3344 connection should not fail is there is a spurious wakeup for io fiber
+test_run:cmd("setopt delimiter ';'")
+echo_fiber = nil
+server = socket.tcp_server('localhost', 0, { handler = function(s)
+ echo_fiber = fiber.self()
+ while true do
+ local b = s:read(1, 0.1)
+ if b ~= nil then
+ s:write(b)
+ end
+ end
+end, name = 'echoserv'});
+test_run:cmd("setopt delimiter ''");
+addr = server:name()
+client = socket.tcp_connect(addr.host, addr.port)
+echo_fiber ~= nil
+client:write('hello')
+client:read(5, 0.1) == 'hello'
+-- send spurious wakeup
+fiber.wakeup(echo_fiber)
+fiber.sleep(0)
+client:write('world')
+client:read(5, 0.1) == 'world'
+-- cancel fiber
+fiber.cancel(echo_fiber)
+client:write('!')
+client:read(1, 0.1) == ''
+server:close()
+
test_run:cmd("clear filter")
--
2.18.0
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