compate/clipped-write.c: large write(2) fails on Mac OS X/XNU
Due to a bug in the Darwin kernel, write(2) calls have a maximum size of INT_MAX bytes. Introduce a new compat function, clipped_write(), that only writes at most INT_MAX bytes and returns the number of bytes written, as a substitute for write(2), and allow platforms that need this to enable it from the build mechanism with NEEDS_CLIPPED_WRITE. Set it for Mac OS X by default. It may be necessary to include this function on Windows, too. Signed-off-by: Filipe Cabecinhas <filcab+git@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Filipe Cabecinhas committed
May 10, 2013 at 15:24 UTC
6c642a878688adf46b226903858b53e2d31ac5c3
4 files changed
+27
Makefile
+8
@@ -69,6 +69,9 @@ all::
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# Define NO_MSGFMT_EXTENDED_OPTIONS if your implementation of msgfmt
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# doesn't support GNU extensions like --check and --statistics
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#
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+# Define NEEDS_CLIPPED_WRITE if your write(2) cannot write more than
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+# INT_MAX bytes at once (e.g. MacOS X).
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+#
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# Define HAVE_PATHS_H if you have paths.h and want to use the default PATH
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# it specifies.
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#
@@ -1463,6 +1466,11 @@ ifndef NO_MSGFMT_EXTENDED_OPTIONS
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MSGFMT += --check --statistics
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endif
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+ifdef NEEDS_CLIPPED_WRITE
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+ BASIC_CFLAGS += -DNEEDS_CLIPPED_WRITE
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+ COMPAT_OBJS += compat/clipped-write.o
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+endif
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+
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ifneq (,$(XDL_FAST_HASH))
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BASIC_CFLAGS += -DXDL_FAST_HASH
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endif
compat/clipped-write.c
new
+13
@@ -0,0 +1,13 @@
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+#include "../git-compat-util.h"
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+#undef write
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+
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+/*
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+ * Version of write that will write at most INT_MAX bytes.
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+ * Workaround a xnu bug on Mac OS X
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+ */
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+ssize_t clipped_write(int fildes, const void *buf, size_t nbyte)
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+{
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+ if (nbyte > INT_MAX)
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+ nbyte = INT_MAX;
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+ return write(fildes, buf, nbyte);
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+}
config.mak.uname
+1
@@ -95,6 +95,7 @@ ifeq ($(uname_S),Darwin)
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NO_MEMMEM = YesPlease
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USE_ST_TIMESPEC = YesPlease
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HAVE_DEV_TTY = YesPlease
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+ NEEDS_CLIPPED_WRITE = YesPlease
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COMPAT_OBJS += compat/precompose_utf8.o
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BASIC_CFLAGS += -DPRECOMPOSE_UNICODE
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endif
git-compat-util.h
+5
@@ -181,6 +181,11 @@ typedef unsigned long uintptr_t;
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#define probe_utf8_pathname_composition(a,b)
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#endif
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+#ifdef NEEDS_CLIPPED_WRITE
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+ssize_t clipped_write(int fildes, const void *buf, size_t nbyte);
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+#define write(x,y,z) clipped_write((x),(y),(z))
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+#endif
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+
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#ifdef MKDIR_WO_TRAILING_SLASH
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#define mkdir(a,b) compat_mkdir_wo_trailing_slash((a),(b))
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extern int compat_mkdir_wo_trailing_slash(const char*, mode_t);