git-commit-vandalism/environment.c
Torsten Bögershausen 76759c7dff git on Mac OS and precomposed unicode
Mac OS X mangles file names containing unicode on file systems HFS+,
VFAT or SAMBA.  When a file using unicode code points outside ASCII
is created on a HFS+ drive, the file name is converted into
decomposed unicode and written to disk. No conversion is done if
the file name is already decomposed unicode.

Calling open("\xc3\x84", ...) with a precomposed "Ä" yields the same
result as open("\x41\xcc\x88",...) with a decomposed "Ä".

As a consequence, readdir() returns the file names in decomposed
unicode, even if the user expects precomposed unicode.  Unlike on
HFS+, Mac OS X stores files on a VFAT drive (e.g. an USB drive) in
precomposed unicode, but readdir() still returns file names in
decomposed unicode.  When a git repository is stored on a network
share using SAMBA, file names are send over the wire and written to
disk on the remote system in precomposed unicode, but Mac OS X
readdir() returns decomposed unicode to be compatible with its
behaviour on HFS+ and VFAT.

The unicode decomposition causes many problems:

- The names "git add" and other commands get from the end user may
  often be precomposed form (the decomposed form is not easily input
  from the keyboard), but when the commands read from the filesystem
  to see what it is going to update the index with already is on the
  filesystem, readdir() will give decomposed form, which is different.

- Similarly "git log", "git mv" and all other commands that need to
  compare pathnames found on the command line (often but not always
  precomposed form; a command line input resulting from globbing may
  be in decomposed) with pathnames found in the tree objects (should
  be precomposed form to be compatible with other systems and for
  consistency in general).

- The same for names stored in the index, which should be
  precomposed, that may need to be compared with the names read from
  readdir().

NFS mounted from Linux is fully transparent and does not suffer from
the above.

As Mac OS X treats precomposed and decomposed file names as equal,
we can

 - wrap readdir() on Mac OS X to return the precomposed form, and

 - normalize decomposed form given from the command line also to the
   precomposed form,

to ensure that all pathnames used in Git are always in the
precomposed form.  This behaviour can be requested by setting
"core.precomposedunicode" configuration variable to true.

The code in compat/precomposed_utf8.c implements basically 4 new
functions: precomposed_utf8_opendir(), precomposed_utf8_readdir(),
precomposed_utf8_closedir() and precompose_argv().  The first three
are to wrap opendir(3), readdir(3), and closedir(3) functions.

The argv[] conversion allows to use the TAB filename completion done
by the shell on command line.  It tolerates other tools which use
readdir() to feed decomposed file names into git.

When creating a new git repository with "git init" or "git clone",
"core.precomposedunicode" will be set "false".

The user needs to activate this feature manually.  She typically
sets core.precomposedunicode to "true" on HFS and VFAT, or file
systems mounted via SAMBA.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-08 22:03:46 -07:00

280 lines
7.4 KiB
C

/*
* We put all the git config variables in this same object
* file, so that programs can link against the config parser
* without having to link against all the rest of git.
*
* In particular, no need to bring in libz etc unless needed,
* even if you might want to know where the git directory etc
* are.
*/
#include "cache.h"
#include "refs.h"
#include "fmt-merge-msg.h"
int trust_executable_bit = 1;
int trust_ctime = 1;
int has_symlinks = 1;
int minimum_abbrev = 4, default_abbrev = 7;
int ignore_case;
int assume_unchanged;
int prefer_symlink_refs;
int is_bare_repository_cfg = -1; /* unspecified */
int log_all_ref_updates = -1; /* unspecified */
int warn_ambiguous_refs = 1;
int repository_format_version;
const char *git_commit_encoding;
const char *git_log_output_encoding;
int shared_repository = PERM_UMASK;
const char *apply_default_whitespace;
const char *apply_default_ignorewhitespace;
const char *git_attributes_file;
int zlib_compression_level = Z_BEST_SPEED;
int core_compression_level;
int core_compression_seen;
int fsync_object_files;
size_t packed_git_window_size = DEFAULT_PACKED_GIT_WINDOW_SIZE;
size_t packed_git_limit = DEFAULT_PACKED_GIT_LIMIT;
size_t delta_base_cache_limit = 16 * 1024 * 1024;
unsigned long big_file_threshold = 512 * 1024 * 1024;
const char *log_pack_access;
const char *pager_program;
int pager_use_color = 1;
const char *editor_program;
const char *askpass_program;
const char *excludes_file;
enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
int read_replace_refs = 1; /* NEEDSWORK: rename to use_replace_refs */
enum eol core_eol = EOL_UNSET;
enum safe_crlf safe_crlf = SAFE_CRLF_WARN;
unsigned whitespace_rule_cfg = WS_DEFAULT_RULE;
enum branch_track git_branch_track = BRANCH_TRACK_REMOTE;
enum rebase_setup_type autorebase = AUTOREBASE_NEVER;
enum push_default_type push_default = PUSH_DEFAULT_UNSPECIFIED;
#ifndef OBJECT_CREATION_MODE
#define OBJECT_CREATION_MODE OBJECT_CREATION_USES_HARDLINKS
#endif
enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
char *notes_ref_name;
int grafts_replace_parents = 1;
int core_apply_sparse_checkout;
int merge_log_config = -1;
int precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */
struct startup_info *startup_info;
unsigned long pack_size_limit_cfg;
/* Parallel index stat data preload? */
int core_preload_index = 0;
/* This is set by setup_git_dir_gently() and/or git_default_config() */
char *git_work_tree_cfg;
static char *work_tree;
static const char *namespace;
static size_t namespace_len;
static const char *git_dir;
static char *git_object_dir, *git_index_file, *git_graft_file;
/*
* Repository-local GIT_* environment variables
* Remember to update local_repo_env_size in cache.h when
* the size of the list changes
*/
const char * const local_repo_env[LOCAL_REPO_ENV_SIZE + 1] = {
ALTERNATE_DB_ENVIRONMENT,
CONFIG_ENVIRONMENT,
CONFIG_DATA_ENVIRONMENT,
DB_ENVIRONMENT,
GIT_DIR_ENVIRONMENT,
GIT_WORK_TREE_ENVIRONMENT,
GRAFT_ENVIRONMENT,
INDEX_ENVIRONMENT,
NO_REPLACE_OBJECTS_ENVIRONMENT,
NULL
};
static char *expand_namespace(const char *raw_namespace)
{
struct strbuf buf = STRBUF_INIT;
struct strbuf **components, **c;
if (!raw_namespace || !*raw_namespace)
return xstrdup("");
strbuf_addstr(&buf, raw_namespace);
components = strbuf_split(&buf, '/');
strbuf_reset(&buf);
for (c = components; *c; c++)
if (strcmp((*c)->buf, "/") != 0)
strbuf_addf(&buf, "refs/namespaces/%s", (*c)->buf);
strbuf_list_free(components);
if (check_refname_format(buf.buf, 0))
die("bad git namespace path \"%s\"", raw_namespace);
strbuf_addch(&buf, '/');
return strbuf_detach(&buf, NULL);
}
static void setup_git_env(void)
{
git_dir = getenv(GIT_DIR_ENVIRONMENT);
git_dir = git_dir ? xstrdup(git_dir) : NULL;
if (!git_dir) {
git_dir = read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
git_dir = git_dir ? xstrdup(git_dir) : NULL;
}
if (!git_dir)
git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
git_object_dir = getenv(DB_ENVIRONMENT);
if (!git_object_dir) {
git_object_dir = xmalloc(strlen(git_dir) + 9);
sprintf(git_object_dir, "%s/objects", git_dir);
}
git_index_file = getenv(INDEX_ENVIRONMENT);
if (!git_index_file) {
git_index_file = xmalloc(strlen(git_dir) + 7);
sprintf(git_index_file, "%s/index", git_dir);
}
git_graft_file = getenv(GRAFT_ENVIRONMENT);
if (!git_graft_file)
git_graft_file = git_pathdup("info/grafts");
if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
read_replace_refs = 0;
namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
namespace_len = strlen(namespace);
}
int is_bare_repository(void)
{
/* if core.bare is not 'false', let's see if there is a work tree */
return is_bare_repository_cfg && !get_git_work_tree();
}
int have_git_dir(void)
{
return !!git_dir;
}
const char *get_git_dir(void)
{
if (!git_dir)
setup_git_env();
return git_dir;
}
const char *get_git_namespace(void)
{
if (!namespace)
setup_git_env();
return namespace;
}
const char *strip_namespace(const char *namespaced_ref)
{
if (prefixcmp(namespaced_ref, get_git_namespace()) != 0)
return NULL;
return namespaced_ref + namespace_len;
}
static int git_work_tree_initialized;
/*
* Note. This works only before you used a work tree. This was added
* primarily to support git-clone to work in a new repository it just
* created, and is not meant to flip between different work trees.
*/
void set_git_work_tree(const char *new_work_tree)
{
if (git_work_tree_initialized) {
new_work_tree = real_path(new_work_tree);
if (strcmp(new_work_tree, work_tree))
die("internal error: work tree has already been set\n"
"Current worktree: %s\nNew worktree: %s",
work_tree, new_work_tree);
return;
}
git_work_tree_initialized = 1;
work_tree = xstrdup(real_path(new_work_tree));
}
const char *get_git_work_tree(void)
{
return work_tree;
}
char *get_object_directory(void)
{
if (!git_object_dir)
setup_git_env();
return git_object_dir;
}
int odb_mkstemp(char *template, size_t limit, const char *pattern)
{
int fd;
/*
* we let the umask do its job, don't try to be more
* restrictive except to remove write permission.
*/
int mode = 0444;
snprintf(template, limit, "%s/%s",
get_object_directory(), pattern);
fd = git_mkstemp_mode(template, mode);
if (0 <= fd)
return fd;
/* slow path */
/* some mkstemp implementations erase template on failure */
snprintf(template, limit, "%s/%s",
get_object_directory(), pattern);
safe_create_leading_directories(template);
return xmkstemp_mode(template, mode);
}
int odb_pack_keep(char *name, size_t namesz, unsigned char *sha1)
{
int fd;
snprintf(name, namesz, "%s/pack/pack-%s.keep",
get_object_directory(), sha1_to_hex(sha1));
fd = open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
if (0 <= fd)
return fd;
/* slow path */
safe_create_leading_directories(name);
return open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
}
char *get_index_file(void)
{
if (!git_index_file)
setup_git_env();
return git_index_file;
}
char *get_graft_file(void)
{
if (!git_graft_file)
setup_git_env();
return git_graft_file;
}
int set_git_dir(const char *path)
{
if (setenv(GIT_DIR_ENVIRONMENT, path, 1))
return error("Could not set GIT_DIR to '%s'", path);
setup_git_env();
return 0;
}
const char *get_log_output_encoding(void)
{
return git_log_output_encoding ? git_log_output_encoding
: get_commit_output_encoding();
}
const char *get_commit_output_encoding(void)
{
return git_commit_encoding ? git_commit_encoding : "UTF-8";
}