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author | Alexander Færøy <ahf@torproject.org> | 2018-11-22 04:49:23 +0100 |
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committer | Nick Mathewson <nickm@torproject.org> | 2018-12-17 16:39:28 -0500 |
commit | bb784cf4f36256a8276ba60641d3ff766b9cd9df (patch) | |
tree | 347af5c98bbeb2edcd4655f6740de9358b70ab62 /src/lib/process/process.c | |
parent | 2e957027e28449d4c3254cc404d154f4bce41bfc (diff) | |
download | tor-bb784cf4f36256a8276ba60641d3ff766b9cd9df.tar.gz tor-bb784cf4f36256a8276ba60641d3ff766b9cd9df.zip |
Add Windows backend for the Process subsystem.
This patch adds support for Microsoft Windows in the Process subsystem.
Libevent does not support mixing different types of handles (sockets,
named pipes, etc.) on Windows in its core event loop code. This have
historically meant that Tor have avoided attaching any non-networking
handles to the event loop. This patch uses a slightly different approach
to roughly support the same features for the Process subsystem as we do
with the Unix backend.
In this patch we use Windows Extended I/O functions (ReadFileEx() and
WriteFileEx()) which executes asynchronously in the background and
executes a completion routine when the scheduled read or write operation
have completed. This is much different from the Unix backend where the
operating system signals to us whenever a file descriptor is "ready" to
either being read from or written to.
To make the Windows operating system execute the completion routines of
ReadFileEx() and WriteFileEx() we must get the Tor process into what
Microsoft calls an "alertable" state. To do this we execute SleepEx()
with a zero millisecond sleep time from a main loop timer that ticks
once a second. This moves the process into the "alertable" state and
when we return from the zero millisecond timeout all the outstanding I/O
completion routines will be called and we can schedule the next reads
and writes.
The timer loop is also responsible for detecting whether our child
processes have terminated since the last timer tick.
See: https://bugs.torproject.org/28179
Diffstat (limited to 'src/lib/process/process.c')
-rw-r--r-- | src/lib/process/process.c | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/src/lib/process/process.c b/src/lib/process/process.c index 8d6a9d3fa0..d4237b2b1f 100644 --- a/src/lib/process/process.c +++ b/src/lib/process/process.c @@ -16,6 +16,7 @@ #include "lib/log/util_bug.h" #include "lib/process/process.h" #include "lib/process/process_unix.h" +#include "lib/process/process_win32.h" #include "lib/process/env.h" #ifdef HAVE_STDDEF_H @@ -69,6 +70,9 @@ struct process_t { #ifndef _WIN32 /** Our Unix process handle. */ process_unix_t *unix_process; +#else + /** Our Win32 process handle. */ + process_win32_t *win32_process; #endif }; @@ -117,6 +121,10 @@ void process_init(void) { processes = smartlist_new(); + +#ifdef _WIN32 + process_win32_init(); +#endif } /** Free up all resources that is handled by the Process subsystem. Note that @@ -124,6 +132,10 @@ process_init(void) void process_free_all(void) { +#ifdef _WIN32 + process_win32_deinit(); +#endif + SMARTLIST_FOREACH(processes, process_t *, x, process_free(x)); smartlist_free(processes); } @@ -170,6 +182,9 @@ process_new(const char *command) #ifndef _WIN32 /* Prepare our Unix process handle. */ process->unix_process = process_unix_new(); +#else + /* Prepare our Win32 process handle. */ + process->win32_process = process_win32_new(); #endif smartlist_add(processes, process); @@ -202,6 +217,9 @@ process_free_(process_t *process) #ifndef _WIN32 /* Cleanup our Unix process handle. */ process_unix_free(process->unix_process); +#else + /* Cleanup our Win32 process handle. */ + process_win32_free(process->win32_process); #endif smartlist_remove(processes, process); @@ -222,6 +240,8 @@ process_exec(process_t *process) #ifndef _WIN32 status = process_unix_exec(process); +#else + status = process_win32_exec(process); #endif /* Update our state. */ @@ -420,6 +440,15 @@ process_get_unix_process(const process_t *process) tor_assert(process->unix_process); return process->unix_process; } +#else +/** Get the internal handle for Windows backend. */ +process_win32_t * +process_get_win32_process(const process_t *process) +{ + tor_assert(process); + tor_assert(process->win32_process); + return process->win32_process; +} #endif /** Write <b>size</b> bytes of <b>data</b> to the given process's standard @@ -544,7 +573,7 @@ MOCK_IMPL(STATIC int, process_read_stdout, (process_t *process, buf_t *buffer)) #ifndef _WIN32 return process_unix_read_stdout(process, buffer); #else - return 0; + return process_win32_read_stdout(process, buffer); #endif } @@ -559,7 +588,7 @@ MOCK_IMPL(STATIC int, process_read_stderr, (process_t *process, buf_t *buffer)) #ifndef _WIN32 return process_unix_read_stderr(process, buffer); #else - return 0; + return process_win32_read_stderr(process, buffer); #endif } @@ -573,6 +602,8 @@ MOCK_IMPL(STATIC void, process_write_stdin, #ifndef _WIN32 process_unix_write(process, buffer); +#else + process_win32_write(process, buffer); #endif } |