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Johannes Schindelin cc0f13c57d get_default_branch_name(): prepare for showing some advice
We are about to introduce a message giving users running `git init` some
advice about `init.defaultBranch`. This will necessarily be done in
`repo_default_branch_name()`.

Not all code paths want to show that advice, though. In particular, the
`git clone` codepath _specifically_ asks for `init_db()` to be quiet,
via the `INIT_DB_QUIET` flag.

In preparation for showing users above-mentioned advice, let's change
the function signature of `get_default_branch_name()` to accept the
parameter `quiet`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-13 15:53:50 -08:00
brian m. carlson 47ac970309 builtin/clone: avoid failure with GIT_DEFAULT_HASH
If a user is cloning a SHA-1 repository with GIT_DEFAULT_HASH set to
"sha256", then we can end up with a repository where the repository
format version is 0 but the extensions.objectformat key is set to
"sha256".  This is both wrong (the user has a SHA-1 repository) and
nonfunctional (because the extension cannot be used in a v0 repository).

This happens because in a clone, we initially set up the repository, and
then change its algorithm based on what the remote side tells us it's
using.  We've initially set up the repository as SHA-256 in this case,
and then later on reset the repository version without clearing the
extension.

We could just always set the extension in this case, but that would mean
that our SHA-1 repositories weren't compatible with older Git versions,
even though there's no reason why they shouldn't be.  And we also don't
want to initialize the repository as SHA-1 initially, since that means
if we're cloning an empty repository, we'll have failed to honor the
GIT_DEFAULT_HASH variable and will end up with a SHA-1 repository, not a
SHA-256 repository.

Neither of those are appealing, so let's tell the repository
initialization code if we're doing a reinit like this, and if so, to
clear the extension if we're using SHA-1.  This makes sure we produce a
valid and functional repository and doesn't break any of our other use
cases.

Reported-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-22 09:22:32 -07:00
Eric Sunshine 59d876ccd6 init: make --separate-git-dir work from within linked worktree
The intention of `git init --separate-work-dir=<path>` is to move the
.git/ directory to a location outside of the main worktree. When used
within a linked worktree, however, rather than moving the .git/
directory as intended, it instead incorrectly moves the worktree's
.git/worktrees/<id> directory to <path>, thus disconnecting the linked
worktree from its parent repository and breaking the worktree in the
process since its local .git file no longer points at a location at
which it can find the object database. Fix this broken behavior.

An intentional side-effect of this change is that it also closes a
loophole not caught by ccf236a23a (init: disallow --separate-git-dir
with bare repository, 2020-08-09) in which the check to prevent
--separate-git-dir being used in conjunction with a bare repository was
unable to detect the invalid combination when invoked from within a
linked worktree. Therefore, add a test to verify that this loophole is
closed, as well.

Reported-by: Henré Botha <henrebotha@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-31 11:47:45 -07:00
Eric Sunshine 42264bc841 init: teach --separate-git-dir to repair linked worktrees
A linked worktree's .git file is a "gitfile" pointing at the
.git/worktrees/<id> directory within the repository. When `git init
--separate-git-dir=<path>` is used on an existing repository to relocate
the repository's .git/ directory to a different location, it neglects to
update the .git files of linked worktrees, thus breaking the worktrees
by making it impossible for them to locate the repository. Fix this by
teaching --separate-git-dir to repair the .git file of each linked
worktree to point at the new repository location.

Reported-by: Henré Botha <henrebotha@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-31 11:47:45 -07:00
Junio C Hamano a654836d96 Merge branch 'es/init-no-separate-git-dir-in-bare'
The purpose of "git init --separate-git-dir" is to initialize a
new project with the repository separate from the working tree,
or, in the case of an existing project, to move the repository
(the .git/ directory) out of the working tree. It does not make
sense to use --separate-git-dir with a bare repository for which
there is no working tree, so disallow its use with bare
repositories.

* es/init-no-separate-git-dir-in-bare:
  init: disallow --separate-git-dir with bare repository
2020-08-24 14:54:28 -07:00
Eric Sunshine ccf236a23a init: disallow --separate-git-dir with bare repository
The purpose of "git init --separate-git-dir" is to separate the
repository from the worktree. This is true even when --separate-git-dir
is used on an existing worktree, in which case, it moves the .git/
subdirectory to a new location outside the worktree.

However, an outright bare repository (such as one created by "git init
--bare"), has no worktree, so using --separate-git-dir to separate it
from its non-existent worktree is nonsensical. Therefore, make it an
error to use --separate-git-dir on a bare repository.

Implementation note: "git init" considers a repository bare if told so
explicitly via --bare or if it guesses it to be so based upon
heuristics. In the explicit --bare case, a conflict with
--separate-git-dir is easy to detect early. In the guessed case,
however, the conflict can only be detected once "bareness" is guessed,
which happens after "git init" has begun creating the repository.
Technically, we can get by with a single late check which would cover
both cases, however, erroring out early, when possible, without leaving
detritus provides a better user experience.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-10 09:24:11 -07:00
brian m. carlson eff45daab8 repository: enable SHA-256 support by default
Now that we have a complete SHA-256 implementation in Git, let's enable
it so people can use it.  Remove the ENABLE_SHA256 define constant
everywhere it's used.  Add tests for initializing a repository with
SHA-256.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30 09:16:49 -07:00
Don Goodman-Wilson 8747ebb7cd init: allow setting the default for the initial branch name via the config
We just introduced the command-line option
`--initial-branch=<branch-name>` to allow initializing a new repository
with a different initial branch than the hard-coded one.

To allow users to override the initial branch name more permanently
(i.e. without having to specify the name manually for each and every
`git init` invocation), let's introduce the `init.defaultBranch` config
setting.

Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Don Goodman-Wilson <don@goodman-wilson.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-24 09:14:21 -07:00
Johannes Schindelin 32ba12dab2 init: allow specifying the initial branch name for the new repository
There is a growing number of projects and companies desiring to change
the main branch name of their repositories (see e.g.
https://twitter.com/mislav/status/1270388510684598272 for background on
this).

To change that branch name for new repositories, currently the only way
to do that automatically is by copying all of Git's template directory,
then hard-coding the desired default branch name into the `.git/HEAD`
file, and then configuring `init.templateDir` to point to those copied
template files.

To make this process much less cumbersome, let's introduce a new option:
`--initial-branch=<branch-name>`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-24 09:14:21 -07:00
Junio C Hamano f8cb64e3d4 Merge branch 'bc/sha-256-part-1-of-4'
SHA-256 transition continues.

* bc/sha-256-part-1-of-4: (22 commits)
  fast-import: add options for rewriting submodules
  fast-import: add a generic function to iterate over marks
  fast-import: make find_marks work on any mark set
  fast-import: add helper function for inserting mark object entries
  fast-import: permit reading multiple marks files
  commit: use expected signature header for SHA-256
  worktree: allow repository version 1
  init-db: move writing repo version into a function
  builtin/init-db: add environment variable for new repo hash
  builtin/init-db: allow specifying hash algorithm on command line
  setup: allow check_repository_format to read repository format
  t/helper: make repository tests hash independent
  t/helper: initialize repository if necessary
  t/helper/test-dump-split-index: initialize git repository
  t6300: make hash algorithm independent
  t6300: abstract away SHA-1-specific constants
  t: use hash-specific lookup tables to define test constants
  repository: require a build flag to use SHA-256
  hex: add functions to parse hex object IDs in any algorithm
  hex: introduce parsing variants taking hash algorithms
  ...
2020-03-26 17:11:20 -07:00
Alexandr Miloslavskiy 0915a5b4cd set_git_dir: fix crash when used with real_path()
`real_path()` returns result from a shared buffer, inviting subtle
reentrance bugs. One of these bugs occur when invoked this way:
    set_git_dir(real_path(git_dir))

In this case, `real_path()` has reentrance:
    real_path
    read_gitfile_gently
    repo_set_gitdir
    setup_git_env
    set_git_dir_1
    set_git_dir

Later, `set_git_dir()` uses its now-dead parameter:
    !is_absolute_path(path)

Fix this by using a dedicated `strbuf` to hold `strbuf_realpath()`.

Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-06 14:45:51 -08:00
brian m. carlson efa7ae36c1 init-db: move writing repo version into a function
When we perform a clone, we won't know the remote side's hash algorithm
until we've read the heads.  Consequently, we'll need to rewrite the
repository format version and hash algorithm once we know what the
remote side has.  Move the code that does this into its own function so
that we can call it from clone in the future.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 09:33:30 -08:00
brian m. carlson 3c9331a129 builtin/init-db: add environment variable for new repo hash
For the foreseeable future, SHA-1 will be the default algorithm for Git.
However, when running the testsuite, we want to be able to test an
arbitrary algorithm. It would be quite burdensome and very untidy to
have to specify the algorithm we'd like to test every time we
initialized a new repository somewhere in the testsuite, so add an
environment variable to allow us to specify the default hash algorithm
for Git.

This has the benefit that we can set it once for the entire testsuite
and not have to think about it. In the future, users can also use it to
set the default for their repositories if they would like to do so.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 09:33:29 -08:00
brian m. carlson 8b8f7189df builtin/init-db: allow specifying hash algorithm on command line
Allow the user to specify the hash algorithm on the command line by
using the --object-format option to git init.  Validate that the user is
not attempting to reinitialize a repository with a different hash
algorithm.  Ensure that if we are writing a non-SHA-1 repository that we
set the repository version to 1 and write the objectFormat extension.

Restrict this option to work only when ENABLE_SHA256 is set until the
codebase is in a situation to fully support this.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 09:33:27 -08:00
brian m. carlson cfe3917c85 setup: allow check_repository_format to read repository format
In some cases, we will want to not only check the repository format, but
extract the information that we've gained.  To do so, allow
check_repository_format to take a pointer to struct repository_format.
Allow passing NULL for this argument if we're not interested in the
information, and pass NULL for all existing callers.  A future patch
will make use of this information.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 09:33:27 -08:00
Junio C Hamano cf3269fba8 Merge branch 'nd/init-relative-template-fix'
A relative pathname given to "git init --template=<path> <repo>"
ought to be relative to the directory "git init" gets invoked in,
but it instead was made relative to the repository, which has been
corrected.

* nd/init-relative-template-fix:
  init: make --template path relative to $CWD
2019-06-13 13:18:46 -07:00
Nguyễn Thái Ngọc Duy e1df7fe43f init: make --template path relative to $CWD
During git-init we chdir() to the target directory, but --template is
not adjusted. So it's relative to the target directory instead of
current directory.

It would be ok if it's documented, but --template in git-init.txt
mentions nothing about this behavior. Change it to be relative to $CWD,
which is much more intuitive.

The changes in the test suite show that this relative-to-target behavior
is actually used. I just hope that it's only used in the test suite and
it's safe to change. Otherwise, the other option is just document
it (i.e. relative to target dir) and move on.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-13 15:13:24 +09:00
Junio C Hamano 63643865d2 Merge branch 'js/init-db-update-for-mingw'
"git init" forgot to read platform-specific repository
configuration, which made Windows port to ignore settings of
core.hidedotfiles, for example.

* js/init-db-update-for-mingw:
  mingw: respect core.hidedotfiles = false in git-init again
2019-04-16 19:28:05 +09:00
Junio C Hamano 6b5688b760 Merge branch 'ma/clear-repository-format'
The setup code has been cleaned up to avoid leaks around the
repository_format structure.

* ma/clear-repository-format:
  setup: fix memory leaks with `struct repository_format`
  setup: free old value before setting `work_tree`
2019-03-20 15:16:07 +09:00
Johannes Schindelin 287853392a mingw: respect core.hidedotfiles = false in git-init again
This is a brown paper bag. When adding the tests, we actually failed
to verify that the config variable is heeded in git-init at all. And
when changing the original patch that marked the .git/ directory as
hidden after reading the config, it was lost on this developer that
the new code would use the hide_dotfiles variable before the config
was read.

The fix is obvious: read the (limited, pre-init) config *before*
creating the .git/ directory.

Please note that we cannot remove the identical-looking `git_config()`
call from `create_default_files()`: we create the `.git/` directory
between those calls. If we removed it, and if the parent directory is
in a Git worktree, and if that worktree's `.git/config` contained any
`init.templatedir` setting, we would all of a sudden pick that up.

This fixes https://github.com/git-for-windows/git/issues/789

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-12 16:30:26 +09:00
Martin Ågren e8805af1c3 setup: fix memory leaks with `struct repository_format`
After we set up a `struct repository_format`, it owns various pieces of
allocated memory. We then either use those members, because we decide we
want to use the "candidate" repository format, or we discard the
candidate / scratch space. In the first case, we transfer ownership of
the memory to a few global variables. In the latter case, we just
silently drop the struct and end up leaking memory.

Introduce an initialization macro `REPOSITORY_FORMAT_INIT` and a
function `clear_repository_format()`, to be used on each side of
`read_repository_format()`. To have a clear and simple memory ownership,
let all users of `struct repository_format` duplicate the strings that
they take from it, rather than stealing the pointers.

Call `clear_...()` at the start of `read_...()` instead of just zeroing
the struct, since we sometimes enter the function multiple times. Thus,
it is important to initialize the struct before calling `read_...()`, so
document that. It's also important because we might not even call
`read_...()` before we call `clear_...()`, see, e.g., builtin/init-db.c.

Teach `read_...()` to clear the struct on error, so that it is reset to
a safe state, and document this. (In `setup_git_directory_gently()`, we
look at `repo_fmt.hash_algo` even if `repo_fmt.version` is -1, which we
weren't actually supposed to do per the API. After this commit, that's
ok.)

We inherit the existing code's combining "error" and "no version found".
Both are signalled through `version == -1` and now both cause us to
clear any partial configuration we have picked up. For "extensions.*",
that's fine, since they require a positive version number. For
"core.bare" and "core.worktree", we're already verifying that we have a
non-negative version number before using them.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-01 08:52:00 +09:00
Junio C Hamano 773e408881 Merge branch 'jk/save-getenv-result'
There were many places the code relied on the string returned from
getenv() to be non-volatile, which is not true, that have been
corrected.

* jk/save-getenv-result:
  builtin_diff(): read $GIT_DIFF_OPTS closer to use
  merge-recursive: copy $GITHEAD strings
  init: make a copy of $GIT_DIR string
  config: make a copy of $GIT_CONFIG string
  commit: copy saved getenv() result
  get_super_prefix(): copy getenv() result
2019-01-29 12:47:54 -08:00
Jeff King e5b07c539d init: make a copy of $GIT_DIR string
We pass the result of getenv("GIT_DIR") to init_db() and assume that the
string remains valid. But that's not guaranteed across calls to setenv()
or even getenv(), although it often works in practice. Let's make a copy
of the string so that we follow the rules.

Note that we need to mark it with UNLEAK(), since the value persists
until the end of program (but we have no opportunity to free it).

This patch also handles $GIT_WORK_TREE the same way. It actually doesn't
have as long a lifetime and is probably fine, but it's simpler to just
treat the two side-by-side variables the same.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-11 18:48:59 -08:00
Jeff King 517fe807d6 assert NOARG/NONEG behavior of parse-options callbacks
When we define a parse-options callback, the flags we put in the option
struct must match what the callback expects. For example, a callback
which does not handle the "unset" parameter should only be used with
PARSE_OPT_NONEG. But since the callback and the option struct are not
defined next to each other, it's easy to get this wrong (as earlier
patches in this series show).

Fortunately, the compiler can help us here: compiling with
-Wunused-parameters can show us which callbacks ignore their "unset"
parameters (and likewise, ones that ignore "arg" expect to be triggered
with PARSE_OPT_NOARG).

But after we've inspected a callback and determined that all of its
callers use the right flags, what do we do next? We'd like to silence
the compiler warning, but do so in a way that will catch any wrong calls
in the future.

We can do that by actually checking those variables and asserting that
they match our expectations. Because this is such a common pattern,
we'll introduce some helper macros. The resulting messages aren't
as descriptive as we could make them, but the file/line information from
BUG() is enough to identify the problem (and anyway, the point is that
these should never be seen).

Each of the annotated callbacks in this patch triggers
-Wunused-parameters, and was manually inspected to make sure all callers
use the correct options (so none of these BUGs should be triggerable).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-06 12:56:29 +09:00
Jeff King 765b496dc6 pass st.st_size as hint for strbuf_readlink()
When we initially added the strbuf_readlink() function in
b11b7e13f4 (Add generic 'strbuf_readlink()' helper function,
2008-12-17), the point was that we generally have a _guess_
as to the correct size based on the stat information, but we
can't necessarily trust it.

Over the years, a few callers have grown up that simply pass
in 0, even though they have the stat information. Let's have
them pass in their hint for consistency (and in theory
efficiency, since it may avoid an extra resize/syscall loop,
but neither location is probably performance critical).

Note that st.st_size is actually an off_t, so in theory we
need xsize_t() here. But none of the other callsites use it,
and since this is just a hint, it doesn't matter either way
(if we wrap we'll simply start with a too-small hint and
then eventually complain when we cannot allocate the
memory).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-24 10:19:29 -07:00
Junio C Hamano ba928e9740 Merge branch 'rd/init-typo'
Message fix.

* rd/init-typo:
  init: fix grammar in "templates not found" msg
2018-06-01 15:06:40 +09:00
Robert P. J. Day 44f560fc16 init: fix grammar in "templates not found" msg
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-30 13:32:40 +09:00
Johannes Schindelin 033abf97fc Replace all die("BUG: ...") calls by BUG() ones
In d8193743e0 (usage.c: add BUG() function, 2017-05-12), a new macro
was introduced to use for reporting bugs instead of die(). It was then
subsequently used to convert one single caller in 588a538ae5
(setup_git_env: convert die("BUG") to BUG(), 2017-05-12).

The cover letter of the patch series containing this patch
(cf 20170513032414.mfrwabt4hovujde2@sigill.intra.peff.net) is not
terribly clear why only one call site was converted, or what the plan
is for other, similar calls to die() to report bugs.

Let's just convert all remaining ones in one fell swoop.

This trick was performed by this invocation:

	sed -i 's/die("BUG: /BUG("/g' $(git grep -l 'die("BUG' \*.c)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-06 19:06:13 +09:00
Stefan Beller d807c4a01d exec_cmd: rename to use dash in file name
This is more consistent with the project style. The majority of Git's
source files use dashes in preference to underscores in their file names.

Signed-off-by: Stefan Beller <sbeller@google.com>
2018-04-11 18:11:00 +09:00
Brandon Williams fa0fccae6a init-db: rename 'template' variables
Rename C++ keyword in order to bring the codebase closer to being able
to be compiled with a C++ compiler.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-22 10:08:05 -08:00
Jeff King 0e5bba53af add UNLEAK annotation for reducing leak false positives
It's a common pattern in git commands to allocate some
memory that should last for the lifetime of the program and
then not bother to free it, relying on the OS to throw it
away.

This keeps the code simple, and it's fast (we don't waste
time traversing structures or calling free at the end of the
program). But it also triggers warnings from memory-leak
checkers like valgrind or LSAN. They know that the memory
was still allocated at program exit, but they don't know
_when_ the leaked memory stopped being useful. If it was
early in the program, then it's probably a real and
important leak. But if it was used right up until program
exit, it's not an interesting leak and we'd like to suppress
it so that we can see the real leaks.

This patch introduces an UNLEAK() macro that lets us do so.
To understand its design, let's first look at some of the
alternatives.

Unfortunately the suppression systems offered by
leak-checking tools don't quite do what we want. A
leak-checker basically knows two things:

  1. Which blocks were allocated via malloc, and the
     callstack during the allocation.

  2. Which blocks were left un-freed at the end of the
     program (and which are unreachable, but more on that
     later).

Their suppressions work by mentioning the function or
callstack of a particular allocation, and marking it as OK
to leak.  So imagine you have code like this:

  int cmd_foo(...)
  {
	/* this allocates some memory */
	char *p = some_function();
	printf("%s", p);
	return 0;
  }

You can say "ignore allocations from some_function(),
they're not leaks". But that's not right. That function may
be called elsewhere, too, and we would potentially want to
know about those leaks.

So you can say "ignore the callstack when main calls
some_function".  That works, but your annotations are
brittle. In this case it's only two functions, but you can
imagine that the actual allocation is much deeper. If any of
the intermediate code changes, you have to update the
suppression.

What we _really_ want to say is that "the value assigned to
p at the end of the function is not a real leak". But
leak-checkers can't understand that; they don't know about
"p" in the first place.

However, we can do something a little bit tricky if we make
some assumptions about how leak-checkers work. They
generally don't just report all un-freed blocks. That would
report even globals which are still accessible when the
leak-check is run.  Instead they take some set of memory
(like BSS) as a root and mark it as "reachable". Then they
scan the reachable blocks for anything that looks like a
pointer to a malloc'd block, and consider that block
reachable. And then they scan those blocks, and so on,
transitively marking anything reachable from a global as
"not leaked" (or at least leaked in a different category).

So we can mark the value of "p" as reachable by putting it
into a variable with program lifetime. One way to do that is
to just mark "p" as static. But that actually affects the
run-time behavior if the function is called twice (you
aren't likely to call main() twice, but some of our cmd_*()
functions are called from other commands).

Instead, we can trick the leak-checker by putting the value
into _any_ reachable bytes. This patch keeps a global
linked-list of bytes copied from "unleaked" variables. That
list is reachable even at program exit, which confers
recursive reachability on whatever values we unleak.

In other words, you can do:

  int cmd_foo(...)
  {
	char *p = some_function();
	printf("%s", p);
	UNLEAK(p);
	return 0;
  }

to annotate "p" and suppress the leak report.

But wait, couldn't we just say "free(p)"? In this toy
example, yes. But UNLEAK()'s byte-copying strategy has
several advantages over actually freeing the memory:

  1. It's recursive across structures. In many cases our "p"
     is not just a pointer, but a complex struct whose
     fields may have been allocated by a sub-function. And
     in some cases (e.g., dir_struct) we don't even have a
     function which knows how to free all of the struct
     members.

     By marking the struct itself as reachable, that confers
     reachability on any pointers it contains (including those
     found in embedded structs, or reachable by walking
     heap blocks recursively.

  2. It works on cases where we're not sure if the value is
     allocated or not. For example:

       char *p = argc > 1 ? argv[1] : some_function();

     It's safe to use UNLEAK(p) here, because it's not
     freeing any memory. In the case that we're pointing to
     argv here, the reachability checker will just ignore
     our bytes.

  3. Likewise, it works even if the variable has _already_
     been freed. We're just copying the pointer bytes. If
     the block has been freed, the leak-checker will skip
     over those bytes as uninteresting.

  4. Because it's not actually freeing memory, you can
     UNLEAK() before we are finished accessing the variable.
     This is helpful in cases like this:

       char *p = some_function();
       return another_function(p);

     Writing this with free() requires:

       int ret;
       char *p = some_function();
       ret = another_function(p);
       free(p);
       return ret;

     But with unleak we can just write:

       char *p = some_function();
       UNLEAK(p);
       return another_function(p);

This patch adds the UNLEAK() macro and enables it
automatically when Git is compiled with SANITIZE=leak.  In
normal builds it's a noop, so we pay no runtime cost.

It also adds some UNLEAK() annotations to show off how the
feature works. On top of other recent leak fixes, these are
enough to get t0000 and t0001 to pass when compiled with
LSAN.

Note the case in commit.c which actually converts a
strbuf_release() into an UNLEAK. This code was already
non-leaky, but the free didn't do anything useful, since
we're exiting. Converting it to an annotation means that
non-leak-checking builds pay no runtime cost. The cost is
minimal enough that it's probably not worth going on a
crusade to convert these kinds of frees to UNLEAKS. I did it
here for consistency with the "sb" leak (though it would
have been equally correct to go the other way, and turn them
both into strbuf_release() calls).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-08 15:43:17 +09:00
Brandon Williams b2141fc1d2 config: don't include config.h by default
Stop including config.h by default in cache.h.  Instead only include
config.h in those files which require use of the config system.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-15 12:56:22 -07:00
Johannes Schindelin ce83eadd9a real_pathdup(): fix callsites that wanted it to die on error
In 4ac9006f83 (real_path: have callers use real_pathdup and
strbuf_realpath, 2016-12-12), we changed the xstrdup(real_path())
pattern to use real_pathdup() directly.

The problem with this change is that real_path() calls
strbuf_realpath() with die_on_error = 1 while real_pathdup() calls
it with die_on_error = 0. Meaning that in cases where real_path()
causes Git to die() with an error message, real_pathdup() is silent
and returns NULL instead.

The callers, however, are ill-prepared for that change, as they expect
the return value to be non-NULL (and otherwise the function died
with an appropriate error message).

Fix this by extending real_pathdup()'s signature to accept the
die_on_error flag and simply pass it through to strbuf_realpath(),
and then adjust all callers after a careful audit whether they would
handle NULLs well.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-08 14:38:41 -08:00
Cornelius Weig 341fb28621 refs: add option core.logAllRefUpdates = always
When core.logallrefupdates is true, we only create a new reflog for refs
that are under certain well-known hierarchies. The reason is that we
know that some hierarchies (like refs/tags) are not meant to change, and
that unknown hierarchies might not want reflogs at all (e.g., a
hypothetical refs/foo might be meant to change often and drop old
history immediately).

However, sometimes it is useful to override this decision and simply log
for all refs, because the safety and audit trail is more important than
the performance implications of keeping the log around.

This patch introduces a new "always" mode for the core.logallrefupdates
option which will log updates to everything under refs/, regardless
where in the hierarchy it is (we still will not log things like
ORIG_HEAD and FETCH_HEAD, which are known to be transient).

Based-on-patch-by: Jeff King <peff@peff.net>
Signed-off-by: Cornelius Weig <cornelius.weig@tngtech.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-31 10:01:24 -08:00
Brandon Williams 4ac9006f83 real_path: have callers use real_pathdup and strbuf_realpath
Migrate callers of real_path() who duplicate the retern value to use
real_pathdup or strbuf_realpath.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-12-12 15:22:32 -08:00
Junio C Hamano 53eb85e623 Merge branch 'nd/init-core-worktree-in-multi-worktree-world'
"git init" tried to record core.worktree in the repository's
'config' file when GIT_WORK_TREE environment variable was set and
it was different from where GIT_DIR appears as ".git" at its top,
but the logic was faulty when .git is a "gitdir:" file that points
at the real place, causing trouble in working trees that are
managed by "git worktree".  This has been corrected.

* nd/init-core-worktree-in-multi-worktree-world:
  init: kill git_link variable
  init: do not set unnecessary core.worktree
  init: kill set_git_dir_init()
  init: call set_git_dir_init() from within init_db()
  init: correct re-initialization from a linked worktree
2016-10-03 13:30:35 -07:00
Nguyễn Thái Ngọc Duy 822d9406c0 init: kill git_link variable
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-25 16:32:35 -07:00
Nguyễn Thái Ngọc Duy 6311cfaf93 init: do not set unnecessary core.worktree
The function needs_work_tree_config() that is called from
create_default_files() is supposed to be fed the path to ".git" that
looks as if it is at the top of the working tree, and decide if that
location matches the actual worktree being used.  This comparison allows
"git init" to decide if core.worktree needs to be recorded in the
working tree.

In the current code, however, we feed the return value from
get_git_dir(), which can be totally different from what the function
expects when "gitdir" file is involved.  Instead of giving the path to
the ".git" at the top of the working tree, we end up feeding the actual
path that the file points at.

This original location of ".git" however is only known to init_db().
Make init_db() save it and have it passed to create_default_files() as a
new parameter, which passes the correct location down to
needs_work_tree_config() to fix this.

Noticed-by: Max Nordlund <max.nordlund@sqore.com>
Helped-by: Michael J Gruber <git@drmicha.warpmail.net>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-25 16:32:35 -07:00
Nguyễn Thái Ngọc Duy 1bd1907951 init: kill set_git_dir_init()
This is a pure code move, necessary to kill the global variable git_link
later (and also helps a bit in the next patch).

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-25 16:32:35 -07:00
Nguyễn Thái Ngọc Duy 33158701e2 init: call set_git_dir_init() from within init_db()
The next commit requires that set_git_dir_init() must be called before
init_db(). Let's make sure nobody can do otherwise.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-25 16:32:35 -07:00
Nguyễn Thái Ngọc Duy fe9aa0b22e init: correct re-initialization from a linked worktree
When 'git init' is called from a linked worktree, we treat '.git'
dir (which is $GIT_COMMON_DIR/worktrees/something) as the main
'.git' (i.e. $GIT_COMMON_DIR) and populate the whole repository skeleton
in there. It does not harm anything (*) but it is still wrong.

Since 'git init' calls set_git_dir() at preparation time, which
indirectly calls get_common_dir() and correctly detects multiple
worktree setup, all git_path_buf() calls in create_default_files() will
return correct paths in both single and multiple worktree setups. The
only thing left is copy_templates(), which targets $GIT_DIR, not
$GIT_COMMON_DIR.

Fix that with get_git_common_dir(). This function will return $GIT_DIR
in single-worktree setup, so we don't have to make a special case for
multiple-worktree here.

(*) It does in fact, thanks to another bug. More on that later.

Noticed-by: Max Nordlund <max.nordlund@sqore.com>
Helped-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-25 16:32:35 -07:00
Junio C Hamano d845d727cb Merge branch 'jk/setup-sequence-update'
There were numerous corner cases in which the configuration files
are read and used or not read at all depending on the directory a
Git command was run, leading to inconsistent behaviour.  The code
to set-up repository access at the beginning of a Git process has
been updated to fix them.

* jk/setup-sequence-update:
  t1007: factor out repeated setup
  init: reset cached config when entering new repo
  init: expand comments explaining config trickery
  config: only read .git/config from configured repos
  test-config: setup git directory
  t1302: use "git -C"
  pager: handle early config
  pager: use callbacks instead of configset
  pager: make pager_program a file-local static
  pager: stop loading git_default_config()
  pager: remove obsolete comment
  diff: always try to set up the repository
  diff: handle --no-index prefixes consistently
  diff: skip implicit no-index check when given --no-index
  patch-id: use RUN_SETUP_GENTLY
  hash-object: always try to set up the git repository
2016-09-21 15:15:24 -07:00
Junio C Hamano 4322f3848a Merge branch 'mh/ref-store'
The ref-store abstraction was introduced to the refs API so that we
can plug in different backends to store references.

* mh/ref-store: (38 commits)
  refs: implement iteration over only per-worktree refs
  refs: make lock generic
  refs: add method to rename refs
  refs: add methods to init refs db
  refs: make delete_refs() virtual
  refs: add method for initial ref transaction commit
  refs: add methods for reflog
  refs: add method iterator_begin
  files_ref_iterator_begin(): take a ref_store argument
  split_symref_update(): add a files_ref_store argument
  lock_ref_sha1_basic(): add a files_ref_store argument
  lock_ref_for_update(): add a files_ref_store argument
  commit_ref_update(): add a files_ref_store argument
  lock_raw_ref(): add a files_ref_store argument
  repack_without_refs(): add a files_ref_store argument
  refs: make peel_ref() virtual
  refs: make create_symref() virtual
  refs: make pack_refs() virtual
  refs: make verify_refname_available() virtual
  refs: make read_raw_ref() virtual
  ...
2016-09-19 13:47:19 -07:00
Jeff King 4543926ba8 init: reset cached config when entering new repo
After we copy the templates into place, we re-read the
config in case we copied in a default config file. But since
git_config() is backed by a cache these days, it's possible
that the call will not actually touch the filesystem at all;
we need to tell it that something has changed behind the
scenes.

Note that we also need to reset the shared_repository
config. At first glance, it seems like this should probably
just be folded into git_config_clear(). But unfortunately
that is not quite right. The shared repository value may
come from config, _or_ it may have been set manually. So
only the caller who knows whether or not they set it is the
one who can clear it (and indeed, if you _do_ put it into
git_config_clear(), then many tests fail, as we have to
clear the config cache any time we set a new config
variable).

There are three tests here. The first two actually pass
already, though it's largely luck: they just don't happen to
actually read any config before we enter the new repo.

But the third one does fail without this patch; we look at
core.sharedrepository while creating the directory, but need
to make sure the value from the template config overrides
it.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-13 15:45:45 -07:00
Jeff King 7c0a842b46 init: expand comments explaining config trickery
git-init may copy "config" from the templates directory and
then re-read it. There are some comments explaining what's
going on here, but they are not grouped very well with the
matching code. Let's rearrange and expand them.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-13 15:45:45 -07:00
David Turner 6fb5acfd8f refs: add methods to init refs db
Alternate refs backends might not need the refs/heads directory and so
on, so we make ref db initialization part of the backend.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:14 -07:00
Vasco Almeida c30364d080 i18n: init-db: join message pieces
Join message displayed during repository initialization in one entire
sentence.  That would improve translations since it's easier translate
an entire sentence than translating each piece.

Update Icelandic translation to reflect the changes.  The Icelandic
translation of these messages is used with test
t0204-gettext-reencode-sanity.sh and not updating the translation would
fail the test.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-17 15:46:10 -07:00
Junio C Hamano 8591654998 Merge branch 'jk/check-repository-format' into maint
The repository set-up sequence has been streamlined (the biggest
change is that there is no longer git_config_early()), so that we
do not attempt to look into refs/* when we know we do not have a
Git repository.

* jk/check-repository-format:
  verify_repository_format: mark messages for translation
  setup: drop repository_format_version global
  setup: unify repository version callbacks
  init: use setup.c's repo version verification
  setup: refactor repo format reading and verification
  config: drop git_config_early
  check_repository_format_gently: stop using git_config_early
  lazily load core.sharedrepository
  wrap shared_repository global in get/set accessors
  setup: document check_repository_format()
2016-05-02 14:24:04 -07:00
Junio C Hamano 907c416534 Merge branch 'jk/check-repository-format'
The repository set-up sequence has been streamlined (the biggest
change is that there is no longer git_config_early()), so that we
do not attempt to look into refs/* when we know we do not have a
Git repository.

* jk/check-repository-format:
  verify_repository_format: mark messages for translation
  setup: drop repository_format_version global
  setup: unify repository version callbacks
  init: use setup.c's repo version verification
  setup: refactor repo format reading and verification
  config: drop git_config_early
  check_repository_format_gently: stop using git_config_early
  lazily load core.sharedrepository
  wrap shared_repository global in get/set accessors
  setup: document check_repository_format()
2016-04-13 14:12:28 -07:00
Jeff King 94ce167249 init: use setup.c's repo version verification
We check our templates to make sure they are from a
version of git we understand (otherwise we would init a
repository we cannot ourselves run in!). But our simple
integer check has fallen behind the times. Let's use the
helpers that setup.c provides to do it right.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-03-11 15:02:23 -08:00