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authorKaren Arutyunov <karen@codesynthesis.com>2017-12-14 02:49:25 +0300
committerKaren Arutyunov <karen@codesynthesis.com>2017-12-14 02:49:25 +0300
commitceb8f4abba2cfc7ac51385fa59693c641151c8d2 (patch)
tree41f0da15e1d8d4ab95dfd73ad3b7cdde9e07eff9
parent326918c41ac1988e373d2aa5edb0ab68e735070c (diff)
Add MSYS processes output probing and bump timeout to two seconds
-rw-r--r--libbutl/process.cxx74
1 files changed, 52 insertions, 22 deletions
diff --git a/libbutl/process.cxx b/libbutl/process.cxx
index 6aa73ce..b9f3b2f 100644
--- a/libbutl/process.cxx
+++ b/libbutl/process.cxx
@@ -1246,13 +1246,13 @@ namespace butl
ulock l (process_spawn_mutex);
inheritability_lock il (l);
- // Resolve file descriptor to HANDLE and make sure it is inherited. Note
- // that the handle is closed either when CloseHandle() is called for it
- // or when _close() is called for the associated file descriptor. Make
- // sure that either the original file descriptor or the resulting HANDLE
- // is closed but not both of them.
+ // Resolve file descriptor to HANDLE and make sure it is inherited (if
+ // requested). Note that the handle is closed either when CloseHandle()
+ // is called for it or when _close() is called for the associated file
+ // descriptor. Make sure that either the original file descriptor or the
+ // resulting HANDLE is closed but not both of them.
//
- auto get_osfhandle = [&fail, &il] (int fd) -> HANDLE
+ auto get_osfhandle = [&fail, &il] (int fd, bool inherit = true) -> HANDLE
{
HANDLE h (reinterpret_cast<HANDLE> (_get_osfhandle (fd)));
if (h == INVALID_HANDLE_VALUE)
@@ -1261,15 +1261,18 @@ namespace butl
// Make the handle inheritable by the child unless it is already
// inheritable.
//
- DWORD f;
- if (!GetHandleInformation (h, &f))
- fail ();
+ if (inherit)
+ {
+ DWORD f;
+ if (!GetHandleInformation (h, &f))
+ fail ();
- // Note that the flag check is essential as SetHandleInformation()
- // fails for standard handles and their duplicates.
- //
- if ((f & HANDLE_FLAG_INHERIT) == 0)
- il.inheritable (h);
+ // Note that the flag check is essential as SetHandleInformation()
+ // fails for standard handles and their duplicates.
+ //
+ if ((f & HANDLE_FLAG_INHERIT) == 0)
+ il.inheritable (h);
+ }
return h;
};
@@ -1474,9 +1477,15 @@ namespace butl
if (msys)
{
- // Wait a bit and check if the process has terminated. If it is
- // still running then we assume all is good. Otherwise, retry if
- // this is the DLL initialization error.
+ // Wait a bit and check if the process has terminated, or has written
+ // some data to stdout or stderr. If it is still running then we
+ // assume all is good. Otherwise, retry if this is the DLL
+ // initialization error.
+ //
+ // Note that the process standard output streams probing is possible
+ // only if they are connected to pipes created by us. We assume that
+ // data presence at the reading end of any of these pipes means that
+ // DLLs initialization successfully passed.
//
system_clock::time_point st (system_clock::now ());
@@ -1487,11 +1496,32 @@ namespace butl
il.unlock ();
l.unlock ();
- // Hidden by butl::duration that is introduced via fdstream.mxx.
- //
- const chrono::duration<DWORD, milli> wd (1000);
+ auto probe_fd = [&get_osfhandle] (int fd) -> bool
+ {
+ if (fd == -1)
+ return false;
- DWORD r (WaitForSingleObject (pi.hProcess, wd.count ()));
+ char c;
+ DWORD n;
+ HANDLE h (get_osfhandle (fd, false));
+ return PeekNamedPipe (h, &c, 1, &n, nullptr, nullptr) && n == 1;
+ };
+
+ DWORD r;
+ system_clock::duration twd (0); // Total wait time.
+ for (size_t n (0); n != 10; ++n) // Wait n times by 200ms.
+ {
+ // Hidden by butl::duration that is introduced via fdstream.mxx.
+ //
+ const chrono::duration<DWORD, milli> wd (200);
+
+ r = WaitForSingleObject (pi.hProcess, wd.count ());
+ twd += wd;
+
+ if (r != WAIT_TIMEOUT ||
+ probe_fd (in_ofd.in.get ()) || probe_fd (in_efd.in.get ()))
+ break;
+ }
if (r == WAIT_OBJECT_0 &&
GetExitCodeProcess (pi.hProcess, &r) &&
@@ -1502,7 +1532,7 @@ namespace butl
// Assume we have waited the full amount if the time adjustment is
// detected.
//
- system_clock::duration d (now > st ? now - st : wd);
+ system_clock::duration d (now > st ? now - st : twd);
// If timeout is not fully exhausted, re-lock the mutex, revert
// handles to inheritable state and re-spawn the process.