From: Stefan-W. Hahn <stefan.hahn@xxxxxxxxx>
Using cygwin with cygwin.dll before 1.5.22 the system call pread() is buggy.
This patch introduces NO_PREAD. If NO_PREAD is set git uses a sequence of
lseek()/xread()/lseek() to emulate pread.
Signed-off-by: Stefan-W. Hahn <stefan.hahn@xxxxxxxxx>
---
Makefile | 7 +++++++
compat/pread.c | 15 +++++++++++++++
git-compat-util.h | 5 +++++
3 files changed, 27 insertions(+), 0 deletions(-)
diff --git a/Makefile b/Makefile
index 6c12bc6..47af0de 100644
--- a/Makefile
+++ b/Makefile
@@ -69,6 +69,9 @@ all:
#
# Define NO_MMAP if you want to avoid mmap.
#
+# Define NO_PREAD if you have a problem with pread() system call (i.e.
+# cygwin.dll before v1.5.22).
+#
# Define NO_FAST_WORKING_DIRECTORY if accessing objects in pack files is
# generally faster on your platform than accessing the working directory.
#
@@ -523,6 +526,10 @@ ifdef NO_MMAP
COMPAT_CFLAGS += -DNO_MMAP
COMPAT_OBJS += compat/mmap.o
endif
+ifdef NO_PREAD
+ COMPAT_CFLAGS += -DNO_PREAD
+ COMPAT_OBJS += compat/pread.o
+endif
ifdef NO_FAST_WORKING_DIRECTORY
BASIC_CFLAGS += -DNO_FAST_WORKING_DIRECTORY
endif
diff --git a/compat/pread.c b/compat/pread.c
new file mode 100644
index 0000000..cd1da87
--- /dev/null
+++ b/compat/pread.c
@@ -0,0 +1,15 @@
+#include "../git-compat-util.h"
+
+ssize_t git_pread(int fd,void *buf,size_t count,off_t offset)
+{
+ off_t current_offset = lseek(fd, 0, SEEK_CUR);
+
+ if (lseek(fd, offset, SEEK_SET) < 0)
+ return EINVAL;
+
+ ssize_t rc=xread(fd, buf, count);
+
+ if (current_offset != lseek(fd, current_offset, SEEK_SET))
+ return EINVAL;
+ return rc;
+}
diff --git a/git-compat-util.h b/git-compat-util.h
index e023bf1..00b14df 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -107,6 +107,11 @@ extern int git_munmap(void *start, size_t length);
#define DEFAULT_PACKED_GIT_LIMIT \
((1024L * 1024L) * (sizeof(void*) >= 8 ? 8192 : 256))
+#ifdef NO_PREAD
+#define pread git_pread
+extern ssize_t git_pread(int fd,void *buf,size_t count,off_t offset);
+#endif
+
#ifdef NO_SETENV
#define setenv gitsetenv
extern int gitsetenv(const char *, const char *, int);
--
1.4.4.4.g46aa
-
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html