diff options
Diffstat (limited to 'patches/ninja-1.8.2/0006-Prepare-PR-for-merging.patch')
| -rw-r--r-- | patches/ninja-1.8.2/0006-Prepare-PR-for-merging.patch | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/patches/ninja-1.8.2/0006-Prepare-PR-for-merging.patch b/patches/ninja-1.8.2/0006-Prepare-PR-for-merging.patch new file mode 100644 index 000000000..bf44d5f4b --- /dev/null +++ b/patches/ninja-1.8.2/0006-Prepare-PR-for-merging.patch @@ -0,0 +1,151 @@ +From: Stefan Becker <chemobejk@gmail.com> +Date: Sat, 7 Apr 2018 17:11:21 +0300 +Subject: [PATCH] Prepare PR for merging + +- fix Windows build error in no-op TokenPool implementation +- improve Acquire() to block for a maximum of 100ms +- address review comments +--- + src/build.h | 2 ++ + src/tokenpool-gnu-make.cc | 53 ++++++++++++++++++++++++++++++++++++++++------- + src/tokenpool-none.cc | 7 +------ + 3 files changed, 49 insertions(+), 13 deletions(-) + +diff --git a/src/build.h b/src/build.h +index 6bc6fea26e94..530812bb9a2a 100644 +--- a/src/build.h ++++ b/src/build.h +@@ -120,6 +120,8 @@ struct CommandRunner { + bool success() const { return status == ExitSuccess; } + }; + /// Wait for a command to complete, or return false if interrupted. ++ /// If more_ready is true then the optional TokenPool is monitored too ++ /// and we return when a token becomes available. + virtual bool WaitForCommand(Result* result, bool more_ready) = 0; + + virtual vector<Edge*> GetActiveEdges() { return vector<Edge*>(); } +diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc +index b0d3e6ebc463..4132bb06d9dd 100644 +--- a/src/tokenpool-gnu-make.cc ++++ b/src/tokenpool-gnu-make.cc +@@ -1,4 +1,4 @@ +-// Copyright 2016-2017 Google Inc. All Rights Reserved. ++// Copyright 2016-2018 Google Inc. All Rights Reserved. + // + // Licensed under the Apache License, Version 2.0 (the "License"); + // you may not use this file except in compliance with the License. +@@ -19,6 +19,7 @@ + #include <poll.h> + #include <unistd.h> + #include <signal.h> ++#include <sys/time.h> + #include <stdio.h> + #include <string.h> + #include <stdlib.h> +@@ -153,6 +154,15 @@ bool GNUmakeTokenPool::Acquire() { + if (available_ > 0) + return true; + ++ // Please read ++ // ++ // http://make.mad-scientist.net/papers/jobserver-implementation/ ++ // ++ // for the reasoning behind the following code. ++ // ++ // Try to read one character from the pipe. Returns true on success. ++ // ++ // First check if read() would succeed without blocking. + #ifdef USE_PPOLL + pollfd pollfds[] = {{rfd_, POLLIN, 0}}; + int ret = poll(pollfds, 1, 0); +@@ -164,33 +174,62 @@ bool GNUmakeTokenPool::Acquire() { + int ret = select(rfd_ + 1, &set, NULL, NULL, &timeout); + #endif + if (ret > 0) { ++ // Handle potential race condition: ++ // - the above check succeeded, i.e. read() should not block ++ // - the character disappears before we call read() ++ // ++ // Create a duplicate of rfd_. The duplicate file descriptor dup_rfd_ ++ // can safely be closed by signal handlers without affecting rfd_. + dup_rfd_ = dup(rfd_); + + if (dup_rfd_ != -1) { + struct sigaction act, old_act; + int ret = 0; + ++ // Temporarily replace SIGCHLD handler with our own + memset(&act, 0, sizeof(act)); + act.sa_handler = CloseDupRfd; + if (sigaction(SIGCHLD, &act, &old_act) == 0) { +- char buf; +- +- // block until token read, child exits or timeout +- alarm(1); +- ret = read(dup_rfd_, &buf, 1); +- alarm(0); ++ struct itimerval timeout; ++ ++ // install a 100ms timeout that generates SIGALARM on expiration ++ memset(&timeout, 0, sizeof(timeout)); ++ timeout.it_value.tv_usec = 100 * 1000; // [ms] -> [usec] ++ if (setitimer(ITIMER_REAL, &timeout, NULL) == 0) { ++ char buf; ++ ++ // Now try to read() from dup_rfd_. Return values from read(): ++ // ++ // 1. token read -> 1 ++ // 2. pipe closed -> 0 ++ // 3. alarm expires -> -1 (EINTR) ++ // 4. child exits -> -1 (EINTR) ++ // 5. alarm expired before entering read() -> -1 (EBADF) ++ // 6. child exited before entering read() -> -1 (EBADF) ++ // 7. child exited before handler is installed -> go to 1 - 3 ++ ret = read(dup_rfd_, &buf, 1); ++ ++ // disarm timer ++ memset(&timeout, 0, sizeof(timeout)); ++ setitimer(ITIMER_REAL, &timeout, NULL); ++ } + + sigaction(SIGCHLD, &old_act, NULL); + } + + CloseDupRfd(0); + ++ // Case 1 from above list + if (ret > 0) { + available_++; + return true; + } + } + } ++ ++ // read() would block, i.e. no token available, ++ // cases 2-6 from above list or ++ // select() / poll() / dup() / sigaction() / setitimer() failed + return false; + } + +diff --git a/src/tokenpool-none.cc b/src/tokenpool-none.cc +index 1c1c499c8d9c..4c592875b4ad 100644 +--- a/src/tokenpool-none.cc ++++ b/src/tokenpool-none.cc +@@ -1,4 +1,4 @@ +-// Copyright 2016-2017 Google Inc. All Rights Reserved. ++// Copyright 2016-2018 Google Inc. All Rights Reserved. + // + // Licensed under the Apache License, Version 2.0 (the "License"); + // you may not use this file except in compliance with the License. +@@ -14,11 +14,6 @@ + + #include "tokenpool.h" + +-#include <fcntl.h> +-#include <poll.h> +-#include <unistd.h> +-#include <stdio.h> +-#include <string.h> + #include <stdlib.h> + + // No-op TokenPool implementation |