Merge branch 'subprocess-communicate-async-pipe' into 'master'

Ensure g_subprocess_communicate_async() never blocks

Closes #2182

See merge request GNOME/glib!1617
This commit is contained in:
Sebastian Dröge 2020-08-17 11:20:13 +00:00
commit 30e4dbdb99

View File

@ -1595,6 +1595,23 @@ g_subprocess_communicate_internal (GSubprocess *subprocess,
if (subprocess->stdin_pipe)
{
g_assert (stdin_buf != NULL);
#ifdef G_OS_UNIX
/* We're doing async writes to the pipe, and the async write mechanism assumes
* that streams polling as writable do SOME progress (possibly partial) and then
* stop, but never block.
*
* However, for blocking pipes, unix will return writable if there is *any* space left
* but still block until the full buffer size is available before returning from write.
* So, to avoid async blocking on the main loop we make this non-blocking here.
*
* It should be safe to change the fd because we're the only user at this point as
* per the g_subprocess_communicate() docs, and all the code called by this function
* properly handles non-blocking fds.
*/
g_unix_set_fd_nonblocking (g_unix_output_stream_get_fd (G_UNIX_OUTPUT_STREAM (subprocess->stdin_pipe)), TRUE, NULL);
#endif
state->stdin_buf = g_memory_input_stream_new_from_bytes (stdin_buf);
g_output_stream_splice_async (subprocess->stdin_pipe, (GInputStream*)state->stdin_buf,
G_OUTPUT_STREAM_SPLICE_CLOSE_SOURCE | G_OUTPUT_STREAM_SPLICE_CLOSE_TARGET,