[PATCH] Set errno to EEXIST if mkdir returns EACCES or EPERM

[Alex Riesen <raa.lkml@gmail.com>]

... and the directory already exists. I.E. Cygwin is such
a case: mkdir fail for mounts which reference directly
to windows mounts ("drives").

---

The discussion, which ended up with this patch can be read
here: http://www.cygwin.com/ml/cygwin/2006-01/msg01276.html

BTW, there is this:
http://www.cygwin.com/ml/cygwin/2006-01/msg01380.html
So this patch will probably be not needed soon.

Still I post it just for reference, or in case someone
can't afford an upgrade.

 Makefile          |    8 ++++++++
 checkout-index.c  |    2 +-
 compat/mkdir.c    |   23 +++++++++++++++++++++++
 git-compat-util.h |    6 ++++++
 4 files changed, 38 insertions(+), 1 deletions(-)
 create mode 100644 compat/mkdir.c

c9f480f5d1e777cc0f4861e94c2449bd8c7cf73a
diff --git a/Makefile b/Makefile
index 2e95353..596c2d8 100644
--- a/Makefile
+++ b/Makefile
@@ -66,6 +66,9 @@ all:
 # Define USE_STDEV below if you want git to care about the underlying device
 # change being considered an inode change from the update-cache perspective.
 
+# Define FIX_MKDIR_ERRNO if your mkdir(2) does not always set errno to EEXIST
+# if it failed because of existing directory (notably Cygwin).
+
 GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE
 	@$(SHELL) ./GIT-VERSION-GEN
 -include GIT-VERSION-FILE
@@ -249,6 +252,7 @@ ifeq ($(uname_O),Cygwin)
 	# Try uncommenting this if you see things break -- YMMV.
 	# NO_MMAP = YesPlease
 	NO_IPV6 = YesPlease
+	FIX_MKDIR_ERRNO = YesPlease
 	X = .exe
 endif
 ifeq ($(uname_S),OpenBSD)
@@ -392,6 +396,10 @@ else
 endif
 endif
 endif
+ifdef FIX_MKDIR_ERRNO
+	COMPAT_CFLAGS += -DFIX_MKDIR_ERRNO
+	COMPAT_OBJS += compat/mkdir.o
+endif
 
 ALL_CFLAGS += -DSHA1_HEADER=$(call shellquote,$(SHA1_HEADER)) $(COMPAT_CFLAGS)
 LIB_OBJS += $(COMPAT_OBJS)
diff --git a/checkout-index.c b/checkout-index.c
index 53dd8cb..c5a6d6e 100644
--- a/checkout-index.c
+++ b/checkout-index.c
@@ -199,6 +199,6 @@ int main(int argc, char **argv)
 	if (0 <= newfd &&
 	    (write_cache(newfd, active_cache, active_nr) ||
 	     commit_index_file(&cache_file)))
-		die("Unable to write new cachefile");
+		die("Unable to write new cachefile: %s", strerror(errno));
 	return 0;
 }
diff --git a/compat/mkdir.c b/compat/mkdir.c
new file mode 100644
index 0000000..1c2260c
--- /dev/null
+++ b/compat/mkdir.c
@@ -0,0 +1,23 @@
+#include <unistd.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include "../git-compat-util.h"
+#undef mkdir
+
+int gitmkdir(const char *dir, mode_t mode)
+{
+	int rc = mkdir(dir, mode);
+	if ( rc < 0 ) {
+		int e  = errno;
+		if ( EACCES == e || EPERM == e )
+		{
+			struct stat st;
+			if ( stat(dir, &st) == 0 )
+				errno = EEXIST;
+			else
+				errno = e;
+		}
+	}
+	return rc;
+}
+
diff --git a/git-compat-util.h b/git-compat-util.h
index f982b8e..9cf3aab 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -154,4 +154,10 @@ static inline int sane_case(int x, int h
 #ifndef MAXPATHLEN
 #define MAXPATHLEN 256
 #endif
+
+#ifdef FIX_MKDIR_ERRNO
+#define mkdir gitmkdir
+int gitmkdir(const char *dir, mode_t mode);
+#endif
+
 #endif
-- 
1.1.4.g7397-dirty