libstdc++: Add workaround for read(2) EINVAL on macOS and FreeBSD [PR102259]

On macOS and FreeBSD the read(2) system call can return EINVAL for large
sizes, so limit the maximum that we try to read. The calling code in
basic_filebuf::xsgetn will loop until it gets the size it wants, so we don't
need to loop in basic_file::xsgetn, just limit the maximum size.

libstdc++-v3/ChangeLog:

	PR libstdc++/102259
	* config/io/basic_file_stdio.cc (basic_file::xsgetn): Limit n to
	_GLIBCXX_MAX_READ_SIZE if that macro is defined.
	* config/os/bsd/darwin/os_defines.h (_GLIBCXX_MAX_READ_SIZE):
	Define to INT_MAX-1.
	* config/os/bsd/freebsd/os_defines.h (_GLIBCXX_MAX_READ_SIZE):
	Likewise.

diff --git a/libstdc++-v3/config/io/basic_file_stdio.cc b/libstdc++-v3/config/io/basic_file_stdio.cc
index 9b529490f08903ae701163dcb90660a2dd41f046..95e6905b3adf43c2533271d712d4849643c5158b 100644 (file)
--- a/libstdc++-v3/config/io/basic_file_stdio.cc
+++ b/libstdc++-v3/config/io/basic_file_stdio.cc
@@ -338,6 +338,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     if (__ret == 0 && ferror(this->file()))
       __ret = -1;
 #else
+
+#ifdef _GLIBCXX_MAX_READ_SIZE
+    if (__builtin_expect(__n > _GLIBCXX_MAX_READ_SIZE, 0))
+      __n = _GLIBCXX_MAX_READ_SIZE;
+#endif
+
     do
       __ret = read(this->fd(), __s, __n);
     while (__ret == -1L && errno == EINTR);

diff --git a/libstdc++-v3/config/os/bsd/darwin/os_defines.h b/libstdc++-v3/config/os/bsd/darwin/os_defines.h
index 6bc7930bdba0964656935ae20f5f45236a20cc97..a9cbdbb557bfbdd567196922a4dfd7c14bf41d9f 100644 (file)
--- a/libstdc++-v3/config/os/bsd/darwin/os_defines.h
+++ b/libstdc++-v3/config/os/bsd/darwin/os_defines.h
@@ -54,4 +54,7 @@
 // No support for referencing weak symbols without a definition.
 #define _GLIBCXX_USE_WEAK_REF 0
 
+// read(2) can return EINVAL for n >= INT_MAX.
+#define _GLIBCXX_MAX_READ_SIZE (__INT_MAX__ - 1)
+
 #endif

diff --git a/libstdc++-v3/config/os/bsd/freebsd/os_defines.h b/libstdc++-v3/config/os/bsd/freebsd/os_defines.h
index 125dfdc18885755ad726e9772776e8fea88078ee..bb4a8442dcce5e673dfec7211968134fac8ea27c 100644 (file)
--- a/libstdc++-v3/config/os/bsd/freebsd/os_defines.h
+++ b/libstdc++-v3/config/os/bsd/freebsd/os_defines.h
@@ -50,4 +50,7 @@
 #define _GLIBCXX_USE_C99_FLOAT_TRANSCENDENTALS_DYNAMIC 0
 #endif
 
+// read(2) can return EINVAL for n >= INT_MAX.
+#define _GLIBCXX_MAX_READ_SIZE (__INT_MAX__ - 1)
+
 #endif