[llvm] c4ef311 - Fix calls to (p)read on macOS when size > INT32_MAX

[Jonas Devlieghere via llvm-commits]

Author: Jonas Devlieghere
Date: 2020-10-26T20:51:44-07:00
New Revision: c4ef3115b4296321090ce33987d6fdf7fa337fc1

URL: https://github.com/llvm/llvm-project/commit/c4ef3115b4296321090ce33987d6fdf7fa337fc1
DIFF: https://github.com/llvm/llvm-project/commit/c4ef3115b4296321090ce33987d6fdf7fa337fc1.diff

LOG: Fix calls to (p)read on macOS when size > INT32_MAX

On macOS, the read and pread syscalls return EINVAL when the number of
bytes to read exceeds INT32_MAX:

https://github.com/apple/darwin-xnu/blob/a449c6a3b8014d9406c2ddbdc81795da24aa7443/bsd/kern/sys_generic.c#L355

rdar://68751407

Differential revision: https://reviews.llvm.org/D90201

Added: 
    

Modified: 
    llvm/lib/Support/Unix/Path.inc

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 01903ea10e81..27b54610867b 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -1066,8 +1066,13 @@ file_t getStdoutHandle() { return 1; }
 file_t getStderrHandle() { return 2; }
 
 Expected<size_t> readNativeFile(file_t FD, MutableArrayRef<char> Buf) {
+#if defined(__APPLE__)
+  size_t Size = std::min<size_t>(Buf.size(), INT32_MAX);
+#else
+  size_t Size = Buf.size();
+#endif
   ssize_t NumRead =
-      sys::RetryAfterSignal(-1, ::read, FD, Buf.data(), Buf.size());
+      sys::RetryAfterSignal(-1, ::read, FD, Buf.data(), Size);
   if (ssize_t(NumRead) == -1)
     return errorCodeToError(std::error_code(errno, std::generic_category()));
   return NumRead;
@@ -1075,14 +1080,19 @@ Expected<size_t> readNativeFile(file_t FD, MutableArrayRef<char> Buf) {
 
 Expected<size_t> readNativeFileSlice(file_t FD, MutableArrayRef<char> Buf,
                                      uint64_t Offset) {
+#if defined(__APPLE__)
+  size_t Size = std::min<size_t>(Buf.size(), INT32_MAX);
+#else
+  size_t Size = Buf.size();
+#endif
 #ifdef HAVE_PREAD
   ssize_t NumRead =
-      sys::RetryAfterSignal(-1, ::pread, FD, Buf.data(), Buf.size(), Offset);
+      sys::RetryAfterSignal(-1, ::pread, FD, Buf.data(), Size, Offset);
 #else
   if (lseek(FD, Offset, SEEK_SET) == -1)
     return errorCodeToError(std::error_code(errno, std::generic_category()));
   ssize_t NumRead =
-      sys::RetryAfterSignal(-1, ::read, FD, Buf.data(), Buf.size());
+      sys::RetryAfterSignal(-1, ::read, FD, Buf.data(), Size);
 #endif
   if (NumRead == -1)
     return errorCodeToError(std::error_code(errno, std::generic_category()));