Some file systems that can host git repositories and their working copies
do not support symbolic links. But then if the repository contains a symbolic
link, it is impossible to check out the working copy.

This patch enables partial support of symbolic links so that it is possible
to check out a working copy on such a file system.  A new flag
core.symlinks (which is true by default) can be set to false to indicate
that the filesystem does not support symbolic links. In this case, symbolic
links that exist in the trees are checked out as small plain files, and
checking in modifications of these files preserve the symlink property in
the database (as long as an entry exists in the index).

Of course, this does not magically make symbolic links work on such defective
file systems; hence, this solution does not help if the working copy relies
on that an entry is a real symbolic link.
Signed-off-by: NJohannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJunio C Hamano <junkio@cox.net>

We currently have two parallel notation for dealing with object types
in the code: a string and a numerical value.  One of them is obviously
redundent, and the most used one requires more stack space and a bunch
of strcmp() all over the place.

This is an initial step for the removal of the version using a char array
found in object reading code paths.  The patch is unfortunately large but
there is no sane way to split it in smaller parts without breaking the
system.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When we do not trust executable bit from lstat(2), we copied
existing ce_mode bits without checking if the filesystem object
is a regular file (which is the only thing we apply the "trust
executable bit" business) nor if the blob in the index is a
regular file (otherwise, we should do the same as registering a
new regular file, which is to default non-executable).

Noticed by Johannes Sixt.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

It is not used after getting written, and just is leaking every time
we write the index out.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

We have a number of badly checked write() calls.  Often we are
expecting write() to write exactly the size we requested or fail,
this fails to handle interrupts or short writes.  Switch to using
the new write_in_full().  Otherwise we at a minimum need to check
for EINTR and EAGAIN, where this is appropriate use xwrite().

Note, the changes to config handling are much larger and handled
in the next patch in the sequence.
Signed-off-by: NAndy Whitcroft <apw@shadowen.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When I converted the mmap() call to xmmap() I failed to cleanup the
way this routine handles errors and left some crufty code behind.
This is a small cleanup, suggested by Johannes.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

In some cases we did not even bother to check the return value of
mmap() and just assume it worked.  This is bad, because if we are
out of virtual address space the kernel returned MAP_FAILED and we
would attempt to dereference that address, segfaulting without any
real error output to the user.

We are replacing all calls to mmap() with xmmap() and moving all
MAP_FAILED checking into that single location.  If a mmap call
fails we try to release enough least-recently-used pack windows
to possibly succeed, then retry the mmap() attempt.  If we cannot
mmap even after releasing pack memory then we die() as none of our
callers have any reasonable recovery strategy for a failed mmap.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When replacing an existing file A with a directory A that has a
file A/B in it in the index, 'update-index --replace --add A/B'
did not properly remove the file to make room for the new
directory.

There was a trivial logic error, most likely a cut & paste one,
dating back to quite early days of git.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When replacing an existing file A with a directory A that has a
file A/B in it in the index, 'git add' did not succeed because
it forgot to pass the allow-replace flag to add_cache_entry().

It might be safer to leave this as an error and require the user
to explicitly remove the existing A first before adding A/B
since it is an unusual case, but doing that automatically is
much easier to use.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When you remove a directory D that has a tracked file D/F out of the
way to create a file D and try to "git update-index --add D", it used
to say "cannot add" which was not very helpful.  This issues an extra
error message to explain the situation before the final "fatal" message.

Since D/F conflicts are relatively rare event, extra verbosity would
not make things too noisy.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

An earlier commit f28b34a broke symlinks when trust-executable-bit
is not set because it incorrectly assumed that everything was a
regular file.

Reported by Juergen Ruehle.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The declaration of discard_cache() in cache.h already has its "void".
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

If the user has configured core.filemode=0 then we shouldn't set
the execute bit in the index when adding a new file as the user
has indicated that the local filesystem can't be trusted.

This means that when adding files that should be marked executable
in a repository with core.filemode=0 the user must perform a
'git update-index --chmod=+x' on the file before committing the
addition.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Introduces global inline:

	hashcmp(const unsigned char *sha1, const unsigned char *sha2)

Uses memcmp for comparison and returns the result based on the length of
the hash name (a future runtime decision).
Acked-by: NAlex Riesen <raa.lkml@gmail.com>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The work-around should not be needed.  Even if it turns out we
would want it later, git will remember the patch for us ;-).
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This will help counting the racily clean paths, but it should be
useless for daily use.  Do not even enable it in the makefile.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

[jc: I needed to hand merge the changes to the updated codebase,
 so the result needs to be checked.]
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

On Solaris nanosleep(2) is not available in libc; you need to
link with -lrt to get it.

The purpose of the loop is to wait until the next filesystem
timestamp granularity, and the code uses subsecond sleep in the
hope that it can shorten the delay to 0.5 seconds on average
instead of a full second.  It is probably not worth depending on
an extra library for this.

We might want to yank out the whole "racy-git avoidance is
costly later at runtime, so let's delay writing the index out"
codepath later, but that is a separate issue and needs some
testing on large trees to figure it out.  After playing with the
kernel tree, I have a feeling that the whole thing may not be
worth it.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Removes conditional returns.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Since add_cacheinfo() can be called without a mapped index file,
discard_cache() _has_ to discard the entries, even when
cache_mmap == NULL.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Instead of looping over the entries and writing out, use a
separate loop after all entries have been written out to check
how many entries are racily clean.  Make sure that the newly
created index file gets the right timestamp when we check by
flushing the buffered data by ce_write().
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Immediately after a bulk checkout, most of the paths in the
working tree would have the same timestamp as the index file,
and this would force ce_match_stat() to take slow path for all
of them.  When writing an index file out, if many of the paths
have very new (read: the same timestamp as the index file being
written out) timestamp, we are better off delaying the return
from the command, to make sure that later command to touch the
working tree files will leave newer timestamps than recorded in
the index, thereby avoiding to take the slow path.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Doing an "strace" on "git diff" shows that we close() a file descriptor
twice (getting EBADFD on the second one) when we end up in ce_compare_data
if the index does not match the checked-out stat information.

The "index_fd()" function will already have closed the fd for us, so we
should not close it again.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This also moves add_file_to_index() to read-cache.c. Oh, and while
touching builtin-add.c, it also removes a duplicate git_config() call.
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This backports the pieces that are not uncooked from the merge-recursive
WIP we have seen earlier, to be used in git-mv rewritten in C.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This is just an update for people being interested. Alex and me were
busy with that project for a few days now. While it has progressed nicely,
there are quite a couple TODOs in merge-recursive.c, just search for "TODO".

For impatient people: yes, it passes all the tests, and yes, according
to the evil test Alex did, it is faster than the Python script.

But no, it is not yet finished. Biggest points are:

- there are still three external calls
- in the end, it should not be necessary to write the index more than once
  (just before exiting)
- a lot of things can be refactored to make the code easier and shorter

BTW we cannot just plug in git-merge-tree yet, because git-merge-tree
does not handle renames at all.

This patch is meant for testing, and as such,

- it compile the program to git-merge-recur
- it adjusts the scripts and tests to use git-merge-recur instead of
  git-merge-recursive
- it provides "TEST", a script to execute the tests regarding -recursive
- it inlines the changes to read-cache.c (read_cache_from(), discard_cache()
  and refresh_cache_entry())

Brought to you by Alex Riesen and Dscho
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This doesn't make the code uglier or harder to read, yet it makes the
code more portable.  This also simplifies checking for other potential
incompatibilities.  "gcc -std=c89 -pedantic" can flag many incompatible
constructs as warnings, but C99 comments will cause it to emit an error.
Signed-off-by: NPavel Roskin <proski@gnu.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

ANSI C99 doesn't allow void-pointer arithmetic. This patch fixes this in
various ways. Usually the strategy that required the least changes was used.
Signed-off-by: NFlorian Forster <octo@verplant.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

In the "next" branch, write_index_ext_header() writes garbage on a
64-bit big-endian machine; the written index file will be unreadable.
I noticed this on NetBSD/sparc64. Reproducible with:

$ git init-db
$ :>file
$ git-update-index --add file
$ git-write-tree
$ git-update-index
error: index uses  extension, which we do not understand
fatal: index file corrupt
Signed-off-by: NDennis Stosberg <dennis@stosberg.net>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This cleans up and libifies the "git update-index --[really-]refresh"
functionality. This will be eventually required for eventually doing the
"commit" and "status" commands as built-ins.

It really just moves "refresh_index()" from update-index.c to
read-cache.c, but it also has to change the calling convention so that the
function uses a "unsigned int flags" argument instead of various static
flags variables for passing down the information about whether to be quiet
or not, and allow unmerged entries etc.

That actually cleans up update-index.c too, since it turns out that all
those flags were really specific to that one function of the index update,
so they shouldn't have had file-scope visibility even before.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

With this one, it's now a fatal error to try to add a pathname
that cannot be added with "git add", i.e.

	[torvalds@g5 git]$ git add .git/config
	fatal: unable to add .git/config to index

and

	[torvalds@g5 git]$ git add foo/../bar
	fatal: unable to add foo/../bar to index

instead of the old "Ignoring path xyz" warning that would end up
silently succeeding on any other paths.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Elsewhere we use xcalloc(); we should consistently do so.
Signed-off-by: NYakov Lerner <iler.ml@gmail.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

... and move the cache-tree data into it.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

read_cache_1() and write_cache_1() takes an extra parameter
*sha1 that returns the checksum of the index file when non-NULL.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The code was a bit unclear in expressing what it wants to compare.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This adds "assume unchanged" logic, started by this message in the list
discussion recently:

	<Pine.LNX.4.64.0601311807470.7301@g5.osdl.org>

This is a workaround for filesystems that do not have lstat()
that is quick enough for the index mechanism to take advantage
of.  On the paths marked as "assumed to be unchanged", the user
needs to explicitly use update-index to register the object name
to be in the next commit.

You can use two new options to update-index to set and reset the
CE_VALID bit:

	git-update-index --assume-unchanged path...
	git-update-index --no-assume-unchanged path...

These forms manipulate only the CE_VALID bit; it does not change
the object name recorded in the index file.  Nor they add a new
entry to the index.

When the configuration variable "core.ignorestat = true" is set,
the index entries are marked with CE_VALID bit automatically
after:

 - update-index to explicitly register the current object name to the
   index file.

 - when update-index --refresh finds the path to be up-to-date.

 - when tools like read-tree -u and apply --index update the working
   tree file and register the current object name to the index file.

The flag is dropped upon read-tree that does not check out the index
entry.  This happens regardless of the core.ignorestat settings.

Index entries marked with CE_VALID bit are assumed to be
unchanged most of the time.  However, there are cases that
CE_VALID bit is ignored for the sake of safety and usability:

 - while "git-read-tree -m" or git-apply need to make sure
   that the paths involved in the merge do not have local
   modifications.  This sacrifices performance for safety.

 - when git-checkout-index -f -q -u -a tries to see if it needs
   to checkout the paths.  Otherwise you can never check
   anything out ;-).

 - when git-update-index --really-refresh (a new flag) tries to
   see if the index entry is up to date.  You can start with
   everything marked as CE_VALID and run this once to drop
   CE_VALID bit for paths that are modified.

Most notably, "update-index --refresh" honours CE_VALID and does
not actively stat, so after you modified a file in the working
tree, update-index --refresh would not notice until you tell the
index about it with "git-update-index path" or "git-update-index
--no-assume-unchanged path".

This version is not expected to be perfect.  I think diff
between index and/or tree and working files may need some
adjustment, and there probably needs other cases we should
automatically unmark paths that are marked to be CE_VALID.

But the basics seem to work, and ready to be tested by people
who asked for this feature.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This is a tricky code and warrants extra commenting.  I wasted
30 minutes trying to break it until I realized why it works.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The previous round caught the most trivial case well, but broke
down once index file is updated again.  Smudge problematic
entries (they should be very few if any under normal interactive
workflow) before writing a new index file out.
Signed-off-by: NJunio C Hamano <junkio@cox.net>