Recommit "[Support] Add RetryAfterSignal helper function"
The difference from the previous version is the use of decltype, as the
implementation of std::result_of in libc++ did not work correctly for
variadic function like open(2).
Original summary:
This function retries an operation if it was interrupted by a signal
(failed with EINTR). It's inspired by the TEMP_FAILURE_RETRY macro in
glibc, but I've turned that into a template function. I've also added a
fail-value argument, to enable the function to be used with e.g.
fopen(3), which is documented to fail for any reason that open(2) can
fail (which includes EINTR).
The main user of this function will be lldb, but there were also a
couple of uses within llvm that I could simplify using this function.
Reviewers: zturner, silvas, joerg
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D33895
llvm-svn: 306671
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index b677469..45097eb 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -737,10 +737,8 @@
#ifdef O_CLOEXEC
OpenFlags |= O_CLOEXEC;
#endif
- while ((ResultFD = open(P.begin(), OpenFlags)) < 0) {
- if (errno != EINTR)
- return std::error_code(errno, std::generic_category());
- }
+ if ((ResultFD = sys::RetryAfterSignal(-1, open, P.begin(), OpenFlags)) < 0)
+ return std::error_code(errno, std::generic_category());
#ifndef O_CLOEXEC
int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
(void)r;
@@ -800,10 +798,8 @@
SmallString<128> Storage;
StringRef P = Name.toNullTerminatedStringRef(Storage);
- while ((ResultFD = open(P.begin(), OpenFlags, Mode)) < 0) {
- if (errno != EINTR)
- return std::error_code(errno, std::generic_category());
- }
+ if ((ResultFD = sys::RetryAfterSignal(-1, open, P.begin(), OpenFlags, Mode)) < 0)
+ return std::error_code(errno, std::generic_category());
#ifndef O_CLOEXEC
int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
(void)r;
diff --git a/llvm/lib/Support/Unix/Process.inc b/llvm/lib/Support/Unix/Process.inc
index 1d0143c..2d46620 100644
--- a/llvm/lib/Support/Unix/Process.inc
+++ b/llvm/lib/Support/Unix/Process.inc
@@ -207,13 +207,10 @@
for (int StandardFD : StandardFDs) {
struct stat st;
errno = 0;
- while (fstat(StandardFD, &st) < 0) {
+ if (RetryAfterSignal(-1, fstat, StandardFD, &st) < 0) {
assert(errno && "expected errno to be set if fstat failed!");
// fstat should return EBADF if the file descriptor is closed.
- if (errno == EBADF)
- break;
- // retry fstat if we got EINTR, otherwise bubble up the failure.
- if (errno != EINTR)
+ if (errno != EBADF)
return std::error_code(errno, std::generic_category());
}
// if fstat succeeds, move on to the next FD.
@@ -222,11 +219,8 @@
assert(errno == EBADF && "expected errno to have EBADF at this point!");
if (NullFD < 0) {
- while ((NullFD = open("/dev/null", O_RDWR)) < 0) {
- if (errno == EINTR)
- continue;
+ if ((NullFD = RetryAfterSignal(-1, open, "/dev/null", O_RDWR)) < 0)
return std::error_code(errno, std::generic_category());
- }
}
if (NullFD == StandardFD)