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authorStefan-W. Hahn <stefan.hahn@s-hahn.de>2007-01-09 22:04:12 +0100
committerJunio C Hamano <junkio@cox.net>2007-01-09 16:40:40 -0800
commit6900679c2f6d937a5a6ef616869c8887690ad19d (patch)
tree138e2f17ba6cd89646c5098ce526e51a4dce5359
parent0bdb28c9ccd85b1c606664154b6f6d39a4c315fd (diff)
downloadgit-6900679c2f6d937a5a6ef616869c8887690ad19d.tar.gz
git-6900679c2f6d937a5a6ef616869c8887690ad19d.tar.xz
Replacing the system call pread() with lseek()/xread()/lseek() sequence.
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@s-hahn.de> Signed-off-by: Junio C Hamano <junkio@cox.net>
-rw-r--r--Makefile7
-rw-r--r--compat/pread.c18
-rw-r--r--git-compat-util.h5
3 files changed, 30 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index 6c12bc64a..43113e9e1 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 (e.g.
+# 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 000000000..978cac4ec
--- /dev/null
+++ b/compat/pread.c
@@ -0,0 +1,18 @@
+#include "../git-compat-util.h"
+
+ssize_t git_pread(int fd, void *buf, size_t count, off_t offset)
+{
+ off_t current_offset;
+ ssize_t rc;
+
+ current_offset = lseek(fd, 0, SEEK_CUR);
+
+ if (lseek(fd, offset, SEEK_SET) < 0)
+ return -1;
+
+ rc = read_in_full(fd, buf, count);
+
+ if (current_offset != lseek(fd, current_offset, SEEK_SET))
+ return -1;
+ return rc;
+}
diff --git a/git-compat-util.h b/git-compat-util.h
index e023bf141..f8d46d587 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);