blob: f21a954ce712bb06aae3b83992e20910dc6b061c [file] [log] [blame]
#include "../cache.h"
#include "../config.h"
#include "../refs.h"
#include "refs-internal.h"
#include "ref-cache.h"
#include "../iterator.h"
#include "../dir-iterator.h"
#include "../lockfile.h"
#include "../object.h"
#include "../dir.h"
struct ref_lock {
char *ref_name;
struct lock_file *lk;
struct object_id old_oid;
};
/*
* Return true if refname, which has the specified oid and flags, can
* be resolved to an object in the database. If the referred-to object
* does not exist, emit a warning and return false.
*/
static int ref_resolves_to_object(const char *refname,
const struct object_id *oid,
unsigned int flags)
{
if (flags & REF_ISBROKEN)
return 0;
if (!has_sha1_file(oid->hash)) {
error("%s does not point to a valid object!", refname);
return 0;
}
return 1;
}
struct packed_ref_cache {
struct ref_cache *cache;
/*
* Count of references to the data structure in this instance,
* including the pointer from files_ref_store::packed if any.
* The data will not be freed as long as the reference count
* is nonzero.
*/
unsigned int referrers;
/* The metadata from when this packed-refs cache was read */
struct stat_validity validity;
};
/*
* Future: need to be in "struct repository"
* when doing a full libification.
*/
struct files_ref_store {
struct ref_store base;
unsigned int store_flags;
char *gitdir;
char *gitcommondir;
char *packed_refs_path;
struct ref_cache *loose;
struct packed_ref_cache *packed;
/*
* Lock used for the "packed-refs" file. Note that this (and
* thus the enclosing `files_ref_store`) must not be freed.
*/
struct lock_file packed_refs_lock;
};
/*
* Increment the reference count of *packed_refs.
*/
static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
{
packed_refs->referrers++;
}
/*
* Decrease the reference count of *packed_refs. If it goes to zero,
* free *packed_refs and return true; otherwise return false.
*/
static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
{
if (!--packed_refs->referrers) {
free_ref_cache(packed_refs->cache);
stat_validity_clear(&packed_refs->validity);
free(packed_refs);
return 1;
} else {
return 0;
}
}
static void clear_packed_ref_cache(struct files_ref_store *refs)
{
if (refs->packed) {
struct packed_ref_cache *packed_refs = refs->packed;
if (is_lock_file_locked(&refs->packed_refs_lock))
die("BUG: packed-ref cache cleared while locked");
refs->packed = NULL;
release_packed_ref_cache(packed_refs);
}
}
static void clear_loose_ref_cache(struct files_ref_store *refs)
{
if (refs->loose) {
free_ref_cache(refs->loose);
refs->loose = NULL;
}
}
/*
* Create a new submodule ref cache and add it to the internal
* set of caches.
*/
static struct ref_store *files_ref_store_create(const char *gitdir,
unsigned int flags)
{
struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
struct ref_store *ref_store = (struct ref_store *)refs;
struct strbuf sb = STRBUF_INIT;
base_ref_store_init(ref_store, &refs_be_files);
refs->store_flags = flags;
refs->gitdir = xstrdup(gitdir);
get_common_dir_noenv(&sb, gitdir);
refs->gitcommondir = strbuf_detach(&sb, NULL);
strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
refs->packed_refs_path = strbuf_detach(&sb, NULL);
return ref_store;
}
/*
* Die if refs is not the main ref store. caller is used in any
* necessary error messages.
*/
static void files_assert_main_repository(struct files_ref_store *refs,
const char *caller)
{
if (refs->store_flags & REF_STORE_MAIN)
return;
die("BUG: operation %s only allowed for main ref store", caller);
}
/*
* Downcast ref_store to files_ref_store. Die if ref_store is not a
* files_ref_store. required_flags is compared with ref_store's
* store_flags to ensure the ref_store has all required capabilities.
* "caller" is used in any necessary error messages.
*/
static struct files_ref_store *files_downcast(struct ref_store *ref_store,
unsigned int required_flags,
const char *caller)
{
struct files_ref_store *refs;
if (ref_store->be != &refs_be_files)
die("BUG: ref_store is type \"%s\" not \"files\" in %s",
ref_store->be->name, caller);
refs = (struct files_ref_store *)ref_store;
if ((refs->store_flags & required_flags) != required_flags)
die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",
caller, required_flags, refs->store_flags);
return refs;
}
/* The length of a peeled reference line in packed-refs, including EOL: */
#define PEELED_LINE_LENGTH 42
/*
* The packed-refs header line that we write out. Perhaps other
* traits will be added later. The trailing space is required.
*/
static const char PACKED_REFS_HEADER[] =
"# pack-refs with: peeled fully-peeled \n";
/*
* Parse one line from a packed-refs file. Write the SHA1 to sha1.
* Return a pointer to the refname within the line (null-terminated),
* or NULL if there was a problem.
*/
static const char *parse_ref_line(struct strbuf *line, struct object_id *oid)
{
const char *ref;
if (parse_oid_hex(line->buf, oid, &ref) < 0)
return NULL;
if (!isspace(*ref++))
return NULL;
if (isspace(*ref))
return NULL;
if (line->buf[line->len - 1] != '\n')
return NULL;
line->buf[--line->len] = 0;
return ref;
}
/*
* Read from `packed_refs_file` into a newly-allocated
* `packed_ref_cache` and return it. The return value will already
* have its reference count incremented.
*
* A comment line of the form "# pack-refs with: " may contain zero or
* more traits. We interpret the traits as follows:
*
* No traits:
*
* Probably no references are peeled. But if the file contains a
* peeled value for a reference, we will use it.
*
* peeled:
*
* References under "refs/tags/", if they *can* be peeled, *are*
* peeled in this file. References outside of "refs/tags/" are
* probably not peeled even if they could have been, but if we find
* a peeled value for such a reference we will use it.
*
* fully-peeled:
*
* All references in the file that can be peeled are peeled.
* Inversely (and this is more important), any references in the
* file for which no peeled value is recorded is not peelable. This
* trait should typically be written alongside "peeled" for
* compatibility with older clients, but we do not require it
* (i.e., "peeled" is a no-op if "fully-peeled" is set).
*/
static struct packed_ref_cache *read_packed_refs(const char *packed_refs_file)
{
FILE *f;
struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs));
struct ref_entry *last = NULL;
struct strbuf line = STRBUF_INIT;
enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
struct ref_dir *dir;
acquire_packed_ref_cache(packed_refs);
packed_refs->cache = create_ref_cache(NULL, NULL);
packed_refs->cache->root->flag &= ~REF_INCOMPLETE;
f = fopen(packed_refs_file, "r");
if (!f) {
if (errno == ENOENT) {
/*
* This is OK; it just means that no
* "packed-refs" file has been written yet,
* which is equivalent to it being empty.
*/
return packed_refs;
} else {
die_errno("couldn't read %s", packed_refs_file);
}
}
stat_validity_update(&packed_refs->validity, fileno(f));
dir = get_ref_dir(packed_refs->cache->root);
while (strbuf_getwholeline(&line, f, '\n') != EOF) {
struct object_id oid;
const char *refname;
const char *traits;
if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
if (strstr(traits, " fully-peeled "))
peeled = PEELED_FULLY;
else if (strstr(traits, " peeled "))
peeled = PEELED_TAGS;
/* perhaps other traits later as well */
continue;
}
refname = parse_ref_line(&line, &oid);
if (refname) {
int flag = REF_ISPACKED;
if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
if (!refname_is_safe(refname))
die("packed refname is dangerous: %s", refname);
oidclr(&oid);
flag |= REF_BAD_NAME | REF_ISBROKEN;
}
last = create_ref_entry(refname, &oid, flag);
if (peeled == PEELED_FULLY ||
(peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
last->flag |= REF_KNOWS_PEELED;
add_ref_entry(dir, last);
continue;
}
if (last &&
line.buf[0] == '^' &&
line.len == PEELED_LINE_LENGTH &&
line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
!get_oid_hex(line.buf + 1, &oid)) {
oidcpy(&last->u.value.peeled, &oid);
/*
* Regardless of what the file header said,
* we definitely know the value of *this*
* reference:
*/
last->flag |= REF_KNOWS_PEELED;
}
}
fclose(f);
strbuf_release(&line);
return packed_refs;
}
static const char *files_packed_refs_path(struct files_ref_store *refs)
{
return refs->packed_refs_path;
}
static void files_reflog_path(struct files_ref_store *refs,
struct strbuf *sb,
const char *refname)
{
if (!refname) {
/*
* FIXME: of course this is wrong in multi worktree
* setting. To be fixed real soon.
*/
strbuf_addf(sb, "%s/logs", refs->gitcommondir);
return;
}
switch (ref_type(refname)) {
case REF_TYPE_PER_WORKTREE:
case REF_TYPE_PSEUDOREF:
strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
break;
case REF_TYPE_NORMAL:
strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
break;
default:
die("BUG: unknown ref type %d of ref %s",
ref_type(refname), refname);
}
}
static void files_ref_path(struct files_ref_store *refs,
struct strbuf *sb,
const char *refname)
{
switch (ref_type(refname)) {
case REF_TYPE_PER_WORKTREE:
case REF_TYPE_PSEUDOREF:
strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
break;
case REF_TYPE_NORMAL:
strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
break;
default:
die("BUG: unknown ref type %d of ref %s",
ref_type(refname), refname);
}
}
/*
* Check that the packed refs cache (if any) still reflects the
* contents of the file. If not, clear the cache.
*/
static void validate_packed_ref_cache(struct files_ref_store *refs)
{
if (refs->packed &&
!stat_validity_check(&refs->packed->validity,
files_packed_refs_path(refs)))
clear_packed_ref_cache(refs);
}
/*
* Get the packed_ref_cache for the specified files_ref_store,
* creating and populating it if it hasn't been read before or if the
* file has been changed (according to its `validity` field) since it
* was last read. On the other hand, if we hold the lock, then assume
* that the file hasn't been changed out from under us, so skip the
* extra `stat()` call in `stat_validity_check()`.
*/
static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
{
const char *packed_refs_file = files_packed_refs_path(refs);
if (!is_lock_file_locked(&refs->packed_refs_lock))
validate_packed_ref_cache(refs);
if (!refs->packed)
refs->packed = read_packed_refs(packed_refs_file);
return refs->packed;
}
static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
{
return get_ref_dir(packed_ref_cache->cache->root);
}
static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
{
return get_packed_ref_dir(get_packed_ref_cache(refs));
}
/*
* Add a reference to the in-memory packed reference cache. This may
* only be called while the packed-refs file is locked (see
* lock_packed_refs()). To actually write the packed-refs file, call
* commit_packed_refs().
*/
static void add_packed_ref(struct files_ref_store *refs,
const char *refname, const struct object_id *oid)
{
struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
if (!is_lock_file_locked(&refs->packed_refs_lock))
die("BUG: packed refs not locked");
if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
die("Reference has invalid format: '%s'", refname);
add_ref_entry(get_packed_ref_dir(packed_ref_cache),
create_ref_entry(refname, oid, REF_ISPACKED));
}
/*
* Read the loose references from the namespace dirname into dir
* (without recursing). dirname must end with '/'. dir must be the
* directory entry corresponding to dirname.
*/
static void loose_fill_ref_dir(struct ref_store *ref_store,
struct ref_dir *dir, const char *dirname)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
DIR *d;
struct dirent *de;
int dirnamelen = strlen(dirname);
struct strbuf refname;
struct strbuf path = STRBUF_INIT;
size_t path_baselen;
files_ref_path(refs, &path, dirname);
path_baselen = path.len;
d = opendir(path.buf);
if (!d) {
strbuf_release(&path);
return;
}
strbuf_init(&refname, dirnamelen + 257);
strbuf_add(&refname, dirname, dirnamelen);
while ((de = readdir(d)) != NULL) {
struct object_id oid;
struct stat st;
int flag;
if (de->d_name[0] == '.')
continue;
if (ends_with(de->d_name, ".lock"))
continue;
strbuf_addstr(&refname, de->d_name);
strbuf_addstr(&path, de->d_name);
if (stat(path.buf, &st) < 0) {
; /* silently ignore */
} else if (S_ISDIR(st.st_mode)) {
strbuf_addch(&refname, '/');
add_entry_to_dir(dir,
create_dir_entry(dir->cache, refname.buf,
refname.len, 1));
} else {
if (!refs_resolve_ref_unsafe(&refs->base,
refname.buf,
RESOLVE_REF_READING,
oid.hash, &flag)) {
oidclr(&oid);
flag |= REF_ISBROKEN;
} else if (is_null_oid(&oid)) {
/*
* It is so astronomically unlikely
* that NULL_SHA1 is the SHA-1 of an
* actual object that we consider its
* appearance in a loose reference
* file to be repo corruption
* (probably due to a software bug).
*/
flag |= REF_ISBROKEN;
}
if (check_refname_format(refname.buf,
REFNAME_ALLOW_ONELEVEL)) {
if (!refname_is_safe(refname.buf))
die("loose refname is dangerous: %s", refname.buf);
oidclr(&oid);
flag |= REF_BAD_NAME | REF_ISBROKEN;
}
add_entry_to_dir(dir,
create_ref_entry(refname.buf, &oid, flag));
}
strbuf_setlen(&refname, dirnamelen);
strbuf_setlen(&path, path_baselen);
}
strbuf_release(&refname);
strbuf_release(&path);
closedir(d);
/*
* Manually add refs/bisect, which, being per-worktree, might
* not appear in the directory listing for refs/ in the main
* repo.
*/
if (!strcmp(dirname, "refs/")) {
int pos = search_ref_dir(dir, "refs/bisect/", 12);
if (pos < 0) {
struct ref_entry *child_entry = create_dir_entry(
dir->cache, "refs/bisect/", 12, 1);
add_entry_to_dir(dir, child_entry);
}
}
}
static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
{
if (!refs->loose) {
/*
* Mark the top-level directory complete because we
* are about to read the only subdirectory that can
* hold references:
*/
refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
/* We're going to fill the top level ourselves: */
refs->loose->root->flag &= ~REF_INCOMPLETE;
/*
* Add an incomplete entry for "refs/" (to be filled
* lazily):
*/
add_entry_to_dir(get_ref_dir(refs->loose->root),
create_dir_entry(refs->loose, "refs/", 5, 1));
}
return refs->loose;
}
/*
* Return the ref_entry for the given refname from the packed
* references. If it does not exist, return NULL.
*/
static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
const char *refname)
{
return find_ref_entry(get_packed_refs(refs), refname);
}
/*
* A loose ref file doesn't exist; check for a packed ref.
*/
static int resolve_packed_ref(struct files_ref_store *refs,
const char *refname,
unsigned char *sha1, unsigned int *flags)
{
struct ref_entry *entry;
/*
* The loose reference file does not exist; check for a packed
* reference.
*/
entry = get_packed_ref(refs, refname);
if (entry) {
hashcpy(sha1, entry->u.value.oid.hash);
*flags |= REF_ISPACKED;
return 0;
}
/* refname is not a packed reference. */
return -1;
}
static int files_read_raw_ref(struct ref_store *ref_store,
const char *refname, unsigned char *sha1,
struct strbuf *referent, unsigned int *type)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
struct strbuf sb_contents = STRBUF_INIT;
struct strbuf sb_path = STRBUF_INIT;
const char *path;
const char *buf;
struct stat st;
int fd;
int ret = -1;
int save_errno;
int remaining_retries = 3;
*type = 0;
strbuf_reset(&sb_path);
files_ref_path(refs, &sb_path, refname);
path = sb_path.buf;
stat_ref:
/*
* We might have to loop back here to avoid a race
* condition: first we lstat() the file, then we try
* to read it as a link or as a file. But if somebody
* changes the type of the file (file <-> directory
* <-> symlink) between the lstat() and reading, then
* we don't want to report that as an error but rather
* try again starting with the lstat().
*
* We'll keep a count of the retries, though, just to avoid
* any confusing situation sending us into an infinite loop.
*/
if (remaining_retries-- <= 0)
goto out;
if (lstat(path, &st) < 0) {
if (errno != ENOENT)
goto out;
if (resolve_packed_ref(refs, refname, sha1, type)) {
errno = ENOENT;
goto out;
}
ret = 0;
goto out;
}
/* Follow "normalized" - ie "refs/.." symlinks by hand */
if (S_ISLNK(st.st_mode)) {
strbuf_reset(&sb_contents);
if (strbuf_readlink(&sb_contents, path, 0) < 0) {
if (errno == ENOENT || errno == EINVAL)
/* inconsistent with lstat; retry */
goto stat_ref;
else
goto out;
}
if (starts_with(sb_contents.buf, "refs/") &&
!check_refname_format(sb_contents.buf, 0)) {
strbuf_swap(&sb_contents, referent);
*type |= REF_ISSYMREF;
ret = 0;
goto out;
}
/*
* It doesn't look like a refname; fall through to just
* treating it like a non-symlink, and reading whatever it
* points to.
*/
}
/* Is it a directory? */
if (S_ISDIR(st.st_mode)) {
/*
* Even though there is a directory where the loose
* ref is supposed to be, there could still be a
* packed ref:
*/
if (resolve_packed_ref(refs, refname, sha1, type)) {
errno = EISDIR;
goto out;
}
ret = 0;
goto out;
}
/*
* Anything else, just open it and try to use it as
* a ref
*/
fd = open(path, O_RDONLY);
if (fd < 0) {
if (errno == ENOENT && !S_ISLNK(st.st_mode))
/* inconsistent with lstat; retry */
goto stat_ref;
else
goto out;
}
strbuf_reset(&sb_contents);
if (strbuf_read(&sb_contents, fd, 256) < 0) {
int save_errno = errno;
close(fd);
errno = save_errno;
goto out;
}
close(fd);
strbuf_rtrim(&sb_contents);
buf = sb_contents.buf;
if (starts_with(buf, "ref:")) {
buf += 4;
while (isspace(*buf))
buf++;
strbuf_reset(referent);
strbuf_addstr(referent, buf);
*type |= REF_ISSYMREF;
ret = 0;
goto out;
}
/*
* Please note that FETCH_HEAD has additional
* data after the sha.
*/
if (get_sha1_hex(buf, sha1) ||
(buf[40] != '\0' && !isspace(buf[40]))) {
*type |= REF_ISBROKEN;
errno = EINVAL;
goto out;
}
ret = 0;
out:
save_errno = errno;
strbuf_release(&sb_path);
strbuf_release(&sb_contents);
errno = save_errno;
return ret;
}
static void unlock_ref(struct ref_lock *lock)
{
/* Do not free lock->lk -- atexit() still looks at them */
if (lock->lk)
rollback_lock_file(lock->lk);
free(lock->ref_name);
free(lock);
}
/*
* Lock refname, without following symrefs, and set *lock_p to point
* at a newly-allocated lock object. Fill in lock->old_oid, referent,
* and type similarly to read_raw_ref().
*
* The caller must verify that refname is a "safe" reference name (in
* the sense of refname_is_safe()) before calling this function.
*
* If the reference doesn't already exist, verify that refname doesn't
* have a D/F conflict with any existing references. extras and skip
* are passed to refs_verify_refname_available() for this check.
*
* If mustexist is not set and the reference is not found or is
* broken, lock the reference anyway but clear sha1.
*
* Return 0 on success. On failure, write an error message to err and
* return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
*
* Implementation note: This function is basically
*
* lock reference
* read_raw_ref()
*
* but it includes a lot more code to
* - Deal with possible races with other processes
* - Avoid calling refs_verify_refname_available() when it can be
* avoided, namely if we were successfully able to read the ref
* - Generate informative error messages in the case of failure
*/
static int lock_raw_ref(struct files_ref_store *refs,
const char *refname, int mustexist,
const struct string_list *extras,
const struct string_list *skip,
struct ref_lock **lock_p,
struct strbuf *referent,
unsigned int *type,
struct strbuf *err)
{
struct ref_lock *lock;
struct strbuf ref_file = STRBUF_INIT;
int attempts_remaining = 3;
int ret = TRANSACTION_GENERIC_ERROR;
assert(err);
files_assert_main_repository(refs, "lock_raw_ref");
*type = 0;
/* First lock the file so it can't change out from under us. */
*lock_p = lock = xcalloc(1, sizeof(*lock));
lock->ref_name = xstrdup(refname);
files_ref_path(refs, &ref_file, refname);
retry:
switch (safe_create_leading_directories(ref_file.buf)) {
case SCLD_OK:
break; /* success */
case SCLD_EXISTS:
/*
* Suppose refname is "refs/foo/bar". We just failed
* to create the containing directory, "refs/foo",
* because there was a non-directory in the way. This
* indicates a D/F conflict, probably because of
* another reference such as "refs/foo". There is no
* reason to expect this error to be transitory.
*/
if (refs_verify_refname_available(&refs->base, refname,
extras, skip, err)) {
if (mustexist) {
/*
* To the user the relevant error is
* that the "mustexist" reference is
* missing:
*/
strbuf_reset(err);
strbuf_addf(err, "unable to resolve reference '%s'",
refname);
} else {
/*
* The error message set by
* refs_verify_refname_available() is
* OK.
*/
ret = TRANSACTION_NAME_CONFLICT;
}
} else {
/*
* The file that is in the way isn't a loose
* reference. Report it as a low-level
* failure.
*/
strbuf_addf(err, "unable to create lock file %s.lock; "
"non-directory in the way",
ref_file.buf);
}
goto error_return;
case SCLD_VANISHED:
/* Maybe another process was tidying up. Try again. */
if (--attempts_remaining > 0)
goto retry;
/* fall through */
default:
strbuf_addf(err, "unable to create directory for %s",
ref_file.buf);
goto error_return;
}
if (!lock->lk)
lock->lk = xcalloc(1, sizeof(struct lock_file));
if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
if (errno == ENOENT && --attempts_remaining > 0) {
/*
* Maybe somebody just deleted one of the
* directories leading to ref_file. Try
* again:
*/
goto retry;
} else {
unable_to_lock_message(ref_file.buf, errno, err);
goto error_return;
}
}
/*
* Now we hold the lock and can read the reference without
* fear that its value will change.
*/
if (files_read_raw_ref(&refs->base, refname,
lock->old_oid.hash, referent, type)) {
if (errno == ENOENT) {
if (mustexist) {
/* Garden variety missing reference. */
strbuf_addf(err, "unable to resolve reference '%s'",
refname);
goto error_return;
} else {
/*
* Reference is missing, but that's OK. We
* know that there is not a conflict with
* another loose reference because
* (supposing that we are trying to lock
* reference "refs/foo/bar"):
*
* - We were successfully able to create
* the lockfile refs/foo/bar.lock, so we
* know there cannot be a loose reference
* named "refs/foo".
*
* - We got ENOENT and not EISDIR, so we
* know that there cannot be a loose
* reference named "refs/foo/bar/baz".
*/
}
} else if (errno == EISDIR) {
/*
* There is a directory in the way. It might have
* contained references that have been deleted. If
* we don't require that the reference already
* exists, try to remove the directory so that it
* doesn't cause trouble when we want to rename the
* lockfile into place later.
*/
if (mustexist) {
/* Garden variety missing reference. */
strbuf_addf(err, "unable to resolve reference '%s'",
refname);
goto error_return;
} else if (remove_dir_recursively(&ref_file,
REMOVE_DIR_EMPTY_ONLY)) {
if (refs_verify_refname_available(
&refs->base, refname,
extras, skip, err)) {
/*
* The error message set by
* verify_refname_available() is OK.
*/
ret = TRANSACTION_NAME_CONFLICT;
goto error_return;
} else {
/*
* We can't delete the directory,
* but we also don't know of any
* references that it should
* contain.
*/
strbuf_addf(err, "there is a non-empty directory '%s' "
"blocking reference '%s'",
ref_file.buf, refname);
goto error_return;
}
}
} else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
strbuf_addf(err, "unable to resolve reference '%s': "
"reference broken", refname);
goto error_return;
} else {
strbuf_addf(err, "unable to resolve reference '%s': %s",
refname, strerror(errno));
goto error_return;
}
/*
* If the ref did not exist and we are creating it,
* make sure there is no existing ref that conflicts
* with refname:
*/
if (refs_verify_refname_available(
&refs->base, refname,
extras, skip, err))
goto error_return;
}
ret = 0;
goto out;
error_return:
unlock_ref(lock);
*lock_p = NULL;
out:
strbuf_release(&ref_file);
return ret;
}
static int files_peel_ref(struct ref_store *ref_store,
const char *refname, unsigned char *sha1)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
"peel_ref");
int flag;
unsigned char base[20];
if (current_ref_iter && current_ref_iter->refname == refname) {
struct object_id peeled;
if (ref_iterator_peel(current_ref_iter, &peeled))
return -1;
hashcpy(sha1, peeled.hash);
return 0;
}
if (refs_read_ref_full(ref_store, refname,
RESOLVE_REF_READING, base, &flag))
return -1;
/*
* If the reference is packed, read its ref_entry from the
* cache in the hope that we already know its peeled value.
* We only try this optimization on packed references because
* (a) forcing the filling of the loose reference cache could
* be expensive and (b) loose references anyway usually do not
* have REF_KNOWS_PEELED.
*/
if (flag & REF_ISPACKED) {
struct ref_entry *r = get_packed_ref(refs, refname);
if (r) {
if (peel_entry(r, 0))
return -1;
hashcpy(sha1, r->u.value.peeled.hash);
return 0;
}
}
return peel_object(base, sha1);
}
struct files_ref_iterator {
struct ref_iterator base;
struct packed_ref_cache *packed_ref_cache;
struct ref_iterator *iter0;
unsigned int flags;
};
static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
{
struct files_ref_iterator *iter =
(struct files_ref_iterator *)ref_iterator;
int ok;
while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
continue;
if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
!ref_resolves_to_object(iter->iter0->refname,
iter->iter0->oid,
iter->iter0->flags))
continue;
iter->base.refname = iter->iter0->refname;
iter->base.oid = iter->iter0->oid;
iter->base.flags = iter->iter0->flags;
return ITER_OK;
}
iter->iter0 = NULL;
if (ref_iterator_abort(ref_iterator) != ITER_DONE)
ok = ITER_ERROR;
return ok;
}
static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
struct object_id *peeled)
{
struct files_ref_iterator *iter =
(struct files_ref_iterator *)ref_iterator;
return ref_iterator_peel(iter->iter0, peeled);
}
static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
{
struct files_ref_iterator *iter =
(struct files_ref_iterator *)ref_iterator;
int ok = ITER_DONE;
if (iter->iter0)
ok = ref_iterator_abort(iter->iter0);
release_packed_ref_cache(iter->packed_ref_cache);
base_ref_iterator_free(ref_iterator);
return ok;
}
static struct ref_iterator_vtable files_ref_iterator_vtable = {
files_ref_iterator_advance,
files_ref_iterator_peel,
files_ref_iterator_abort
};
static struct ref_iterator *files_ref_iterator_begin(
struct ref_store *ref_store,
const char *prefix, unsigned int flags)
{
struct files_ref_store *refs;
struct ref_iterator *loose_iter, *packed_iter;
struct files_ref_iterator *iter;
struct ref_iterator *ref_iterator;
unsigned int required_flags = REF_STORE_READ;
if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
required_flags |= REF_STORE_ODB;
refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
iter = xcalloc(1, sizeof(*iter));
ref_iterator = &iter->base;
base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
/*
* We must make sure that all loose refs are read before
* accessing the packed-refs file; this avoids a race
* condition if loose refs are migrated to the packed-refs
* file by a simultaneous process, but our in-memory view is
* from before the migration. We ensure this as follows:
* First, we call start the loose refs iteration with its
* `prime_ref` argument set to true. This causes the loose
* references in the subtree to be pre-read into the cache.
* (If they've already been read, that's OK; we only need to
* guarantee that they're read before the packed refs, not
* *how much* before.) After that, we call
* get_packed_ref_cache(), which internally checks whether the
* packed-ref cache is up to date with what is on disk, and
* re-reads it if not.
*/
loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
prefix, 1);
iter->packed_ref_cache = get_packed_ref_cache(refs);
acquire_packed_ref_cache(iter->packed_ref_cache);
packed_iter = cache_ref_iterator_begin(iter->packed_ref_cache->cache,
prefix, 0);
iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
iter->flags = flags;
return ref_iterator;
}
/*
* Verify that the reference locked by lock has the value old_sha1.
* Fail if the reference doesn't exist and mustexist is set. Return 0
* on success. On error, write an error message to err, set errno, and
* return a negative value.
*/
static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
const unsigned char *old_sha1, int mustexist,
struct strbuf *err)
{
assert(err);
if (refs_read_ref_full(ref_store, lock->ref_name,
mustexist ? RESOLVE_REF_READING : 0,
lock->old_oid.hash, NULL)) {
if (old_sha1) {
int save_errno = errno;
strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
errno = save_errno;
return -1;
} else {
oidclr(&lock->old_oid);
return 0;
}
}
if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
strbuf_addf(err, "ref '%s' is at %s but expected %s",
lock->ref_name,
oid_to_hex(&lock->old_oid),
sha1_to_hex(old_sha1));
errno = EBUSY;
return -1;
}
return 0;
}
static int remove_empty_directories(struct strbuf *path)
{
/*
* we want to create a file but there is a directory there;
* if that is an empty directory (or a directory that contains
* only empty directories), remove them.
*/
return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
}
static int create_reflock(const char *path, void *cb)
{
struct lock_file *lk = cb;
return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
}
/*
* Locks a ref returning the lock on success and NULL on failure.
* On failure errno is set to something meaningful.
*/
static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
const char *refname,
const unsigned char *old_sha1,
const struct string_list *extras,
const struct string_list *skip,
unsigned int flags, int *type,
struct strbuf *err)
{
struct strbuf ref_file = STRBUF_INIT;
struct ref_lock *lock;
int last_errno = 0;
int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
int resolve_flags = RESOLVE_REF_NO_RECURSE;
int resolved;
files_assert_main_repository(refs, "lock_ref_sha1_basic");
assert(err);
lock = xcalloc(1, sizeof(struct ref_lock));
if (mustexist)
resolve_flags |= RESOLVE_REF_READING;
if (flags & REF_DELETING)
resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
files_ref_path(refs, &ref_file, refname);
resolved = !!refs_resolve_ref_unsafe(&refs->base,
refname, resolve_flags,
lock->old_oid.hash, type);
if (!resolved && errno == EISDIR) {
/*
* we are trying to lock foo but we used to
* have foo/bar which now does not exist;
* it is normal for the empty directory 'foo'
* to remain.
*/
if (remove_empty_directories(&ref_file)) {
last_errno = errno;
if (!refs_verify_refname_available(
&refs->base,
refname, extras, skip, err))
strbuf_addf(err, "there are still refs under '%s'",
refname);
goto error_return;
}
resolved = !!refs_resolve_ref_unsafe(&refs->base,
refname, resolve_flags,
lock->old_oid.hash, type);
}
if (!resolved) {
last_errno = errno;
if (last_errno != ENOTDIR ||
!refs_verify_refname_available(&refs->base, refname,
extras, skip, err))
strbuf_addf(err, "unable to resolve reference '%s': %s",
refname, strerror(last_errno));
goto error_return;
}
/*
* If the ref did not exist and we are creating it, make sure
* there is no existing packed ref whose name begins with our
* refname, nor a packed ref whose name is a proper prefix of
* our refname.
*/
if (is_null_oid(&lock->old_oid) &&
refs_verify_refname_available(&refs->base, refname,
extras, skip, err)) {
last_errno = ENOTDIR;
goto error_return;
}
lock->lk = xcalloc(1, sizeof(struct lock_file));
lock->ref_name = xstrdup(refname);
if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
last_errno = errno;
unable_to_lock_message(ref_file.buf, errno, err);
goto error_return;
}
if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
last_errno = errno;
goto error_return;
}
goto out;
error_return:
unlock_ref(lock);
lock = NULL;
out:
strbuf_release(&ref_file);
errno = last_errno;
return lock;
}
/*
* Write an entry to the packed-refs file for the specified refname.
* If peeled is non-NULL, write it as the entry's peeled value.
*/
static void write_packed_entry(FILE *fh, const char *refname,
const unsigned char *sha1,
const unsigned char *peeled)
{
fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
if (peeled)
fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
}
/*
* Lock the packed-refs file for writing. Flags is passed to
* hold_lock_file_for_update(). Return 0 on success. On errors, set
* errno appropriately and return a nonzero value.
*/
static int lock_packed_refs(struct files_ref_store *refs, int flags)
{
static int timeout_configured = 0;
static int timeout_value = 1000;
struct packed_ref_cache *packed_ref_cache;
files_assert_main_repository(refs, "lock_packed_refs");
if (!timeout_configured) {
git_config_get_int("core.packedrefstimeout", &timeout_value);
timeout_configured = 1;
}
if (hold_lock_file_for_update_timeout(
&refs->packed_refs_lock, files_packed_refs_path(refs),
flags, timeout_value) < 0)
return -1;
/*
* Now that we hold the `packed-refs` lock, make sure that our
* cache matches the current version of the file. Normally
* `get_packed_ref_cache()` does that for us, but that
* function assumes that when the file is locked, any existing
* cache is still valid. We've just locked the file, but it
* might have changed the moment *before* we locked it.
*/
validate_packed_ref_cache(refs);
packed_ref_cache = get_packed_ref_cache(refs);
/* Increment the reference count to prevent it from being freed: */
acquire_packed_ref_cache(packed_ref_cache);
return 0;
}
/*
* Write the current version of the packed refs cache from memory to
* disk. The packed-refs file must already be locked for writing (see
* lock_packed_refs()). Return zero on success. On errors, set errno
* and return a nonzero value
*/
static int commit_packed_refs(struct files_ref_store *refs)
{
struct packed_ref_cache *packed_ref_cache =
get_packed_ref_cache(refs);
int ok, error = 0;
int save_errno = 0;
FILE *out;
struct ref_iterator *iter;
files_assert_main_repository(refs, "commit_packed_refs");
if (!is_lock_file_locked(&refs->packed_refs_lock))
die("BUG: packed-refs not locked");
out = fdopen_lock_file(&refs->packed_refs_lock, "w");
if (!out)
die_errno("unable to fdopen packed-refs descriptor");
fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
iter = cache_ref_iterator_begin(packed_ref_cache->cache, NULL, 0);
while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
struct object_id peeled;
int peel_error = ref_iterator_peel(iter, &peeled);
write_packed_entry(out, iter->refname, iter->oid->hash,
peel_error ? NULL : peeled.hash);
}
if (ok != ITER_DONE)
die("error while iterating over references");
if (commit_lock_file(&refs->packed_refs_lock)) {
save_errno = errno;
error = -1;
}
release_packed_ref_cache(packed_ref_cache);
errno = save_errno;
return error;
}
/*
* Rollback the lockfile for the packed-refs file, and discard the
* in-memory packed reference cache. (The packed-refs file will be
* read anew if it is needed again after this function is called.)
*/
static void rollback_packed_refs(struct files_ref_store *refs)
{
struct packed_ref_cache *packed_ref_cache =
get_packed_ref_cache(refs);
files_assert_main_repository(refs, "rollback_packed_refs");
if (!is_lock_file_locked(&refs->packed_refs_lock))
die("BUG: packed-refs not locked");
rollback_lock_file(&refs->packed_refs_lock);
release_packed_ref_cache(packed_ref_cache);
clear_packed_ref_cache(refs);
}
struct ref_to_prune {
struct ref_to_prune *next;
unsigned char sha1[20];
char name[FLEX_ARRAY];
};
enum {
REMOVE_EMPTY_PARENTS_REF = 0x01,
REMOVE_EMPTY_PARENTS_REFLOG = 0x02
};
/*
* Remove empty parent directories associated with the specified
* reference and/or its reflog, but spare [logs/]refs/ and immediate
* subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
* REMOVE_EMPTY_PARENTS_REFLOG.
*/
static void try_remove_empty_parents(struct files_ref_store *refs,
const char *refname,
unsigned int flags)
{
struct strbuf buf = STRBUF_INIT;
struct strbuf sb = STRBUF_INIT;
char *p, *q;
int i;
strbuf_addstr(&buf, refname);
p = buf.buf;
for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
while (*p && *p != '/')
p++;
/* tolerate duplicate slashes; see check_refname_format() */
while (*p == '/')
p++;
}
q = buf.buf + buf.len;
while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
while (q > p && *q != '/')
q--;
while (q > p && *(q-1) == '/')
q--;
if (q == p)
break;
strbuf_setlen(&buf, q - buf.buf);
strbuf_reset(&sb);
files_ref_path(refs, &sb, buf.buf);
if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
flags &= ~REMOVE_EMPTY_PARENTS_REF;
strbuf_reset(&sb);
files_reflog_path(refs, &sb, buf.buf);
if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
}
strbuf_release(&buf);
strbuf_release(&sb);
}
/* make sure nobody touched the ref, and unlink */
static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
{
struct ref_transaction *transaction;
struct strbuf err = STRBUF_INIT;
if (check_refname_format(r->name, 0))
return;
transaction = ref_store_transaction_begin(&refs->base, &err);
if (!transaction ||
ref_transaction_delete(transaction, r->name, r->sha1,
REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
ref_transaction_commit(transaction, &err)) {
ref_transaction_free(transaction);
error("%s", err.buf);
strbuf_release(&err);
return;
}
ref_transaction_free(transaction);
strbuf_release(&err);
}
static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
{
while (r) {
prune_ref(refs, r);
r = r->next;
}
}
/*
* Return true if the specified reference should be packed.
*/
static int should_pack_ref(const char *refname,
const struct object_id *oid, unsigned int ref_flags,
unsigned int pack_flags)
{
/* Do not pack per-worktree refs: */
if (ref_type(refname) != REF_TYPE_NORMAL)
return 0;
/* Do not pack non-tags unless PACK_REFS_ALL is set: */
if (!(pack_flags & PACK_REFS_ALL) && !starts_with(refname, "refs/tags/"))
return 0;
/* Do not pack symbolic refs: */
if (ref_flags & REF_ISSYMREF)
return 0;
/* Do not pack broken refs: */
if (!ref_resolves_to_object(refname, oid, ref_flags))
return 0;
return 1;
}
static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
"pack_refs");
struct ref_iterator *iter;
struct ref_dir *packed_refs;
int ok;
struct ref_to_prune *refs_to_prune = NULL;
lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
packed_refs = get_packed_refs(refs);
iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
/*
* If the loose reference can be packed, add an entry
* in the packed ref cache. If the reference should be
* pruned, also add it to refs_to_prune.
*/
struct ref_entry *packed_entry;
if (!should_pack_ref(iter->refname, iter->oid, iter->flags,
flags))
continue;
/*
* Create an entry in the packed-refs cache equivalent
* to the one from the loose ref cache, except that
* we don't copy the peeled status, because we want it
* to be re-peeled.
*/
packed_entry = find_ref_entry(packed_refs, iter->refname);
if (packed_entry) {
/* Overwrite existing packed entry with info from loose entry */
packed_entry->flag = REF_ISPACKED;
oidcpy(&packed_entry->u.value.oid, iter->oid);
} else {
packed_entry = create_ref_entry(iter->refname, iter->oid,
REF_ISPACKED);
add_ref_entry(packed_refs, packed_entry);
}
oidclr(&packed_entry->u.value.peeled);
/* Schedule the loose reference for pruning if requested. */
if ((flags & PACK_REFS_PRUNE)) {
struct ref_to_prune *n;
FLEX_ALLOC_STR(n, name, iter->refname);
hashcpy(n->sha1, iter->oid->hash);
n->next = refs_to_prune;
refs_to_prune = n;
}
}
if (ok != ITER_DONE)
die("error while iterating over references");
if (commit_packed_refs(refs))
die_errno("unable to overwrite old ref-pack file");
prune_refs(refs, refs_to_prune);
return 0;
}
/*
* Rewrite the packed-refs file, omitting any refs listed in
* 'refnames'. On error, leave packed-refs unchanged, write an error
* message to 'err', and return a nonzero value.
*
* The refs in 'refnames' needn't be sorted. `err` must not be NULL.
*/
static int repack_without_refs(struct files_ref_store *refs,
struct string_list *refnames, struct strbuf *err)
{
struct ref_dir *packed;
struct string_list_item *refname;
int ret, needs_repacking = 0, removed = 0;
files_assert_main_repository(refs, "repack_without_refs");
assert(err);
/* Look for a packed ref */
for_each_string_list_item(refname, refnames) {
if (get_packed_ref(refs, refname->string)) {
needs_repacking = 1;
break;
}
}
/* Avoid locking if we have nothing to do */
if (!needs_repacking)
return 0; /* no refname exists in packed refs */
if (lock_packed_refs(refs, 0)) {
unable_to_lock_message(files_packed_refs_path(refs), errno, err);
return -1;
}
packed = get_packed_refs(refs);
/* Remove refnames from the cache */
for_each_string_list_item(refname, refnames)
if (remove_entry_from_dir(packed, refname->string) != -1)
removed = 1;
if (!removed) {
/*
* All packed entries disappeared while we were
* acquiring the lock.
*/
rollback_packed_refs(refs);
return 0;
}
/* Write what remains */
ret = commit_packed_refs(refs);
if (ret)
strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
strerror(errno));
return ret;
}
static int files_delete_refs(struct ref_store *ref_store, const char *msg,
struct string_list *refnames, unsigned int flags)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
struct strbuf err = STRBUF_INIT;
int i, result = 0;
if (!refnames->nr)
return 0;
result = repack_without_refs(refs, refnames, &err);
if (result) {
/*
* If we failed to rewrite the packed-refs file, then
* it is unsafe to try to remove loose refs, because
* doing so might expose an obsolete packed value for
* a reference that might even point at an object that
* has been garbage collected.
*/
if (refnames->nr == 1)
error(_("could not delete reference %s: %s"),
refnames->items[0].string, err.buf);
else
error(_("could not delete references: %s"), err.buf);
goto out;
}
for (i = 0; i < refnames->nr; i++) {
const char *refname = refnames->items[i].string;
if (refs_delete_ref(&refs->base, msg, refname, NULL, flags))
result |= error(_("could not remove reference %s"), refname);
}
out:
strbuf_release(&err);
return result;
}
/*
* People using contrib's git-new-workdir have .git/logs/refs ->
* /some/other/path/.git/logs/refs, and that may live on another device.
*
* IOW, to avoid cross device rename errors, the temporary renamed log must
* live into logs/refs.
*/
#define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
struct rename_cb {
const char *tmp_renamed_log;
int true_errno;
};
static int rename_tmp_log_callback(const char *path, void *cb_data)
{
struct rename_cb *cb = cb_data;
if (rename(cb->tmp_renamed_log, path)) {
/*
* rename(a, b) when b is an existing directory ought
* to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
* Sheesh. Record the true errno for error reporting,
* but report EISDIR to raceproof_create_file() so
* that it knows to retry.
*/
cb->true_errno = errno;
if (errno == ENOTDIR)
errno = EISDIR;
return -1;
} else {
return 0;
}
}
static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
{
struct strbuf path = STRBUF_INIT;
struct strbuf tmp = STRBUF_INIT;
struct rename_cb cb;
int ret;
files_reflog_path(refs, &path, newrefname);
files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
cb.tmp_renamed_log = tmp.buf;
ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
if (ret) {
if (errno == EISDIR)
error("directory not empty: %s", path.buf);
else
error("unable to move logfile %s to %s: %s",
tmp.buf, path.buf,
strerror(cb.true_errno));
}
strbuf_release(&path);
strbuf_release(&tmp);
return ret;
}
static int write_ref_to_lockfile(struct ref_lock *lock,
const struct object_id *oid, struct strbuf *err);
static int commit_ref_update(struct files_ref_store *refs,
struct ref_lock *lock,
const struct object_id *oid, const char *logmsg,
struct strbuf *err);
static int files_rename_ref(struct ref_store *ref_store,
const char *oldrefname, const char *newrefname,
const char *logmsg)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
struct object_id oid, orig_oid;
int flag = 0, logmoved = 0;
struct ref_lock *lock;
struct stat loginfo;
struct strbuf sb_oldref = STRBUF_INIT;
struct strbuf sb_newref = STRBUF_INIT;
struct strbuf tmp_renamed_log = STRBUF_INIT;
int log, ret;
struct strbuf err = STRBUF_INIT;
files_reflog_path(refs, &sb_oldref, oldrefname);
files_reflog_path(refs, &sb_newref, newrefname);
files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
log = !lstat(sb_oldref.buf, &loginfo);
if (log && S_ISLNK(loginfo.st_mode)) {
ret = error("reflog for %s is a symlink", oldrefname);
goto out;
}
if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
orig_oid.hash, &flag)) {
ret = error("refname %s not found", oldrefname);
goto out;
}
if (flag & REF_ISSYMREF) {
ret = error("refname %s is a symbolic ref, renaming it is not supported",
oldrefname);
goto out;
}
if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
ret = 1;
goto out;
}
if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
oldrefname, strerror(errno));
goto out;
}
if (refs_delete_ref(&refs->base, logmsg, oldrefname,
orig_oid.hash, REF_NODEREF)) {
error("unable to delete old %s", oldrefname);
goto rollback;
}
/*
* Since we are doing a shallow lookup, oid is not the
* correct value to pass to delete_ref as old_oid. But that
* doesn't matter, because an old_oid check wouldn't add to
* the safety anyway; we want to delete the reference whatever
* its current value.
*/
if (!refs_read_ref_full(&refs->base, newrefname,
RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
oid.hash, NULL) &&
refs_delete_ref(&refs->base, NULL, newrefname,
NULL, REF_NODEREF)) {
if (errno == EISDIR) {
struct strbuf path = STRBUF_INIT;
int result;
files_ref_path(refs, &path, newrefname);
result = remove_empty_directories(&path);
strbuf_release(&path);
if (result) {
error("Directory not empty: %s", newrefname);
goto rollback;
}
} else {
error("unable to delete existing %s", newrefname);
goto rollback;
}
}
if (log && rename_tmp_log(refs, newrefname))
goto rollback;
logmoved = log;
lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
REF_NODEREF, NULL, &err);
if (!lock) {
error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
strbuf_release(&err);
goto rollback;
}
oidcpy(&lock->old_oid, &orig_oid);
if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
error("unable to write current sha1 into %s: %s", newrefname, err.buf);
strbuf_release(&err);
goto rollback;
}
ret = 0;
goto out;
rollback:
lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
REF_NODEREF, NULL, &err);
if (!lock) {
error("unable to lock %s for rollback: %s", oldrefname, err.buf);
strbuf_release(&err);
goto rollbacklog;
}
flag = log_all_ref_updates;
log_all_ref_updates = LOG_REFS_NONE;
if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
strbuf_release(&err);
}
log_all_ref_updates = flag;
rollbacklog:
if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
error("unable to restore logfile %s from %s: %s",
oldrefname, newrefname, strerror(errno));
if (!logmoved && log &&
rename(tmp_renamed_log.buf, sb_oldref.buf))
error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
oldrefname, strerror(errno));
ret = 1;
out:
strbuf_release(&sb_newref);
strbuf_release(&sb_oldref);
strbuf_release(&tmp_renamed_log);
return ret;
}
static int close_ref(struct ref_lock *lock)
{
if (close_lock_file(lock->lk))
return -1;
return 0;
}
static int commit_ref(struct ref_lock *lock)
{
char *path = get_locked_file_path(lock->lk);
struct stat st;
if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
/*
* There is a directory at the path we want to rename
* the lockfile to. Hopefully it is empty; try to
* delete it.
*/
size_t len = strlen(path);
struct strbuf sb_path = STRBUF_INIT;
strbuf_attach(&sb_path, path, len, len);
/*
* If this fails, commit_lock_file() will also fail
* and will report the problem.
*/
remove_empty_directories(&sb_path);
strbuf_release(&sb_path);
} else {
free(path);
}
if (commit_lock_file(lock->lk))
return -1;
return 0;
}
static int open_or_create_logfile(const char *path, void *cb)
{
int *fd = cb;
*fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
return (*fd < 0) ? -1 : 0;
}
/*
* Create a reflog for a ref. If force_create = 0, only create the
* reflog for certain refs (those for which should_autocreate_reflog
* returns non-zero). Otherwise, create it regardless of the reference
* name. If the logfile already existed or was created, return 0 and
* set *logfd to the file descriptor opened for appending to the file.
* If no logfile exists and we decided not to create one, return 0 and
* set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
* return -1.
*/
static int log_ref_setup(struct files_ref_store *refs,
const char *refname, int force_create,
int *logfd, struct strbuf *err)
{
struct strbuf logfile_sb = STRBUF_INIT;
char *logfile;
files_reflog_path(refs, &logfile_sb, refname);
logfile = strbuf_detach(&logfile_sb, NULL);
if (force_create || should_autocreate_reflog(refname)) {
if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
if (errno == ENOENT)
strbuf_addf(err, "unable to create directory for '%s': "
"%s", logfile, strerror(errno));
else if (errno == EISDIR)
strbuf_addf(err, "there are still logs under '%s'",
logfile);
else
strbuf_addf(err, "unable to append to '%s': %s",
logfile, strerror(errno));
goto error;
}
} else {
*logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
if (*logfd < 0) {
if (errno == ENOENT || errno == EISDIR) {
/*
* The logfile doesn't already exist,
* but that is not an error; it only
* means that we won't write log
* entries to it.
*/
;
} else {
strbuf_addf(err, "unable to append to '%s': %s",
logfile, strerror(errno));
goto error;
}
}
}
if (*logfd >= 0)
adjust_shared_perm(logfile);
free(logfile);
return 0;
error:
free(logfile);
return -1;
}
static int files_create_reflog(struct ref_store *ref_store,
const char *refname, int force_create,
struct strbuf *err)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
int fd;
if (log_ref_setup(refs, refname, force_create, &fd, err))
return -1;
if (fd >= 0)
close(fd);
return 0;
}
static int log_ref_write_fd(int fd, const struct object_id *old_oid,
const struct object_id *new_oid,
const char *committer, const char *msg)
{
int msglen, written;
unsigned maxlen, len;
char *logrec;
msglen = msg ? strlen(msg) : 0;
maxlen = strlen(committer) + msglen + 100;
logrec = xmalloc(maxlen);
len = xsnprintf(logrec, maxlen, "%s %s %s\n",
oid_to_hex(old_oid),
oid_to_hex(new_oid),
committer);
if (msglen)
len += copy_reflog_msg(logrec + len - 1, msg) - 1;
written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
free(logrec);
if (written < 0)
return -1;
return 0;
}
static int files_log_ref_write(struct files_ref_store *refs,
const char *refname, const struct object_id *old_oid,
const struct object_id *new_oid, const char *msg,
int flags, struct strbuf *err)
{
int logfd, result;
if (log_all_ref_updates == LOG_REFS_UNSET)
log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
result = log_ref_setup(refs, refname,
flags & REF_FORCE_CREATE_REFLOG,
&logfd, err);
if (result)
return result;
if (logfd < 0)
return 0;
result = log_ref_write_fd(logfd, old_oid, new_oid,
git_committer_info(0), msg);
if (result) {
struct strbuf sb = STRBUF_INIT;
int save_errno = errno;
files_reflog_path(refs, &sb, refname);
strbuf_addf(err, "unable to append to '%s': %s",
sb.buf, strerror(save_errno));
strbuf_release(&sb);
close(logfd);
return -1;
}
if (close(logfd)) {
struct strbuf sb = STRBUF_INIT;
int save_errno = errno;
files_reflog_path(refs, &sb, refname);
strbuf_addf(err, "unable to append to '%s': %s",
sb.buf, strerror(save_errno));
strbuf_release(&sb);
return -1;
}
return 0;
}
/*
* Write sha1 into the open lockfile, then close the lockfile. On
* errors, rollback the lockfile, fill in *err and
* return -1.
*/
static int write_ref_to_lockfile(struct ref_lock *lock,
const struct object_id *oid, struct strbuf *err)
{
static char term = '\n';
struct object *o;
int fd;
o = parse_object(oid);
if (!o) {
strbuf_addf(err,
"trying to write ref '%s' with nonexistent object %s",
lock->ref_name, oid_to_hex(oid));
unlock_ref(lock);
return -1;
}
if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
strbuf_addf(err,
"trying to write non-commit object %s to branch '%s'",
oid_to_hex(oid), lock->ref_name);
unlock_ref(lock);
return -1;
}
fd = get_lock_file_fd(lock->lk);
if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) < 0 ||
write_in_full(fd, &term, 1) < 0 ||
close_ref(lock) < 0) {
strbuf_addf(err,
"couldn't write '%s'", get_lock_file_path(lock->lk));
unlock_ref(lock);
return -1;
}
return 0;
}
/*
* Commit a change to a loose reference that has already been written
* to the loose reference lockfile. Also update the reflogs if
* necessary, using the specified lockmsg (which can be NULL).
*/
static int commit_ref_update(struct files_ref_store *refs,
struct ref_lock *lock,
const struct object_id *oid, const char *logmsg,
struct strbuf *err)
{
files_assert_main_repository(refs, "commit_ref_update");
clear_loose_ref_cache(refs);
if (files_log_ref_write(refs, lock->ref_name,
&lock->old_oid, oid,
logmsg, 0, err)) {
char *old_msg = strbuf_detach(err, NULL);
strbuf_addf(err, "cannot update the ref '%s': %s",
lock->ref_name, old_msg);
free(old_msg);
unlock_ref(lock);
return -1;
}
if (strcmp(lock->ref_name, "HEAD") != 0) {
/*
* Special hack: If a branch is updated directly and HEAD
* points to it (may happen on the remote side of a push
* for example) then logically the HEAD reflog should be
* updated too.
* A generic solution implies reverse symref information,
* but finding all symrefs pointing to the given branch
* would be rather costly for this rare event (the direct
* update of a branch) to be worth it. So let's cheat and
* check with HEAD only which should cover 99% of all usage
* scenarios (even 100% of the default ones).
*/
struct object_id head_oid;
int head_flag;
const char *head_ref;
head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
RESOLVE_REF_READING,
head_oid.hash, &head_flag);
if (head_ref && (head_flag & REF_ISSYMREF) &&
!strcmp(head_ref, lock->ref_name)) {
struct strbuf log_err = STRBUF_INIT;
if (files_log_ref_write(refs, "HEAD",
&lock->old_oid, oid,
logmsg, 0, &log_err)) {
error("%s", log_err.buf);
strbuf_release(&log_err);
}
}
}
if (commit_ref(lock)) {
strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
unlock_ref(lock);
return -1;
}
unlock_ref(lock);
return 0;
}
static int create_ref_symlink(struct ref_lock *lock, const char *target)
{
int ret = -1;
#ifndef NO_SYMLINK_HEAD
char *ref_path = get_locked_file_path(lock->lk);
unlink(ref_path);
ret = symlink(target, ref_path);
free(ref_path);
if (ret)
fprintf(stderr, "no symlink - falling back to symbolic ref\n");
#endif
return ret;
}
static void update_symref_reflog(struct files_ref_store *refs,
struct ref_lock *lock, const char *refname,
const char *target, const char *logmsg)
{
struct strbuf err = STRBUF_INIT;
struct object_id new_oid;
if (logmsg &&
!refs_read_ref_full(&refs->base, target,
RESOLVE_REF_READING, new_oid.hash, NULL) &&
files_log_ref_write(refs, refname, &lock->old_oid,
&new_oid, logmsg, 0, &err)) {
error("%s", err.buf);
strbuf_release(&err);
}
}
static int create_symref_locked(struct files_ref_store *refs,
struct ref_lock *lock, const char *refname,
const char *target, const char *logmsg)
{
if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
update_symref_reflog(refs, lock, refname, target, logmsg);
return 0;
}
if (!fdopen_lock_file(lock->lk, "w"))
return error("unable to fdopen %s: %s",
lock->lk->tempfile.filename.buf, strerror(errno));
update_symref_reflog(refs, lock, refname, target, logmsg);
/* no error check; commit_ref will check ferror */
fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
if (commit_ref(lock) < 0)
return error("unable to write symref for %s: %s", refname,
strerror(errno));
return 0;
}
static int files_create_symref(struct ref_store *ref_store,
const char *refname, const char *target,
const char *logmsg)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
struct strbuf err = STRBUF_INIT;
struct ref_lock *lock;
int ret;
lock = lock_ref_sha1_basic(refs, refname, NULL,
NULL, NULL, REF_NODEREF, NULL,
&err);
if (!lock) {
error("%s", err.buf);
strbuf_release(&err);
return -1;
}
ret = create_symref_locked(refs, lock, refname, target, logmsg);
unlock_ref(lock);
return ret;
}
static int files_reflog_exists(struct ref_store *ref_store,
const char *refname)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
struct strbuf sb = STRBUF_INIT;
struct stat st;
int ret;
files_reflog_path(refs, &sb, refname);
ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
strbuf_release(&sb);
return ret;
}
static int files_delete_reflog(struct ref_store *ref_store,
const char *refname)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
struct strbuf sb = STRBUF_INIT;
int ret;
files_reflog_path(refs, &sb, refname);
ret = remove_path(sb.buf);
strbuf_release(&sb);
return ret;
}
static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
{
struct object_id ooid, noid;
char *email_end, *message;
timestamp_t timestamp;
int tz;
const char *p = sb->buf;
/* old SP new SP name <email> SP time TAB msg LF */
if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
!(email_end = strchr(p, '>')) ||
email_end[1] != ' ' ||
!(timestamp = parse_timestamp(email_end + 2, &message, 10)) ||
!message || message[0] != ' ' ||
(message[1] != '+' && message[1] != '-') ||
!isdigit(message[2]) || !isdigit(message[3]) ||
!isdigit(message[4]) || !isdigit(message[5]))
return 0; /* corrupt? */
email_end[1] = '\0';
tz = strtol(message + 1, NULL, 10);
if (message[6] != '\t')
message += 6;
else
message += 7;
return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
}
static char *find_beginning_of_line(char *bob, char *scan)
{
while (bob < scan && *(--scan) != '\n')
; /* keep scanning backwards */
/*
* Return either beginning of the buffer, or LF at the end of
* the previous line.
*/
return scan;
}
static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
const char *refname,
each_reflog_ent_fn fn,
void *cb_data)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ,
"for_each_reflog_ent_reverse");
struct strbuf sb = STRBUF_INIT;
FILE *logfp;
long pos;
int ret = 0, at_tail = 1;
files_reflog_path(refs, &sb, refname);
logfp = fopen(sb.buf, "r");
strbuf_release(&sb);
if (!logfp)
return -1;
/* Jump to the end */
if (fseek(logfp, 0, SEEK_END) < 0)
ret = error("cannot seek back reflog for %s: %s",
refname, strerror(errno));
pos = ftell(logfp);
while (!ret && 0 < pos) {
int cnt;
size_t nread;
char buf[BUFSIZ];
char *endp, *scanp;
/* Fill next block from the end */
cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
if (fseek(logfp, pos - cnt, SEEK_SET)) {
ret = error("cannot seek back reflog for %s: %s",
refname, strerror(errno));
break;
}
nread = fread(buf, cnt, 1, logfp);
if (nread != 1) {
ret = error("cannot read %d bytes from reflog for %s: %s",
cnt, refname, strerror(errno));
break;
}
pos -= cnt;
scanp = endp = buf + cnt;
if (at_tail && scanp[-1] == '\n')
/* Looking at the final LF at the end of the file */
scanp--;
at_tail = 0;
while (buf < scanp) {
/*
* terminating LF of the previous line, or the beginning
* of the buffer.
*/
char *bp;
bp = find_beginning_of_line(buf, scanp);
if (*bp == '\n') {
/*
* The newline is the end of the previous line,
* so we know we have complete line starting
* at (bp + 1). Prefix it onto any prior data
* we collected for the line and process it.
*/
strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
scanp = bp;
endp = bp + 1;
ret = show_one_reflog_ent(&sb, fn, cb_data);
strbuf_reset(&sb);
if (ret)
break;
} else if (!pos) {
/*
* We are at the start of the buffer, and the
* start of the file; there is no previous
* line, and we have everything for this one.
* Process it, and we can end the loop.
*/
strbuf_splice(&sb, 0, 0, buf, endp - buf);
ret = show_one_reflog_ent(&sb, fn, cb_data);
strbuf_reset(&sb);
break;
}
if (bp == buf) {
/*
* We are at the start of the buffer, and there
* is more file to read backwards. Which means
* we are in the middle of a line. Note that we
* may get here even if *bp was a newline; that
* just means we are at the exact end of the
* previous line, rather than some spot in the
* middle.
*
* Save away what we have to be combined with
* the data from the next read.
*/
strbuf_splice(&sb, 0, 0, buf, endp - buf);
break;
}
}
}
if (!ret && sb.len)
die("BUG: reverse reflog parser had leftover data");
fclose(logfp);
strbuf_release(&sb);
return ret;
}
static int files_for_each_reflog_ent(struct ref_store *ref_store,
const char *refname,
each_reflog_ent_fn fn, void *cb_data)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ,
"for_each_reflog_ent");
FILE *logfp;
struct strbuf sb = STRBUF_INIT;
int ret = 0;
files_reflog_path(refs, &sb, refname);
logfp = fopen(sb.buf, "r");
strbuf_release(&sb);
if (!logfp)
return -1;
while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
ret = show_one_reflog_ent(&sb, fn, cb_data);
fclose(logfp);
strbuf_release(&sb);
return ret;
}
struct files_reflog_iterator {
struct ref_iterator base;
struct ref_store *ref_store;
struct dir_iterator *dir_iterator;
struct object_id oid;
};
static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
{
struct files_reflog_iterator *iter =
(struct files_reflog_iterator *)ref_iterator;
struct dir_iterator *diter = iter->dir_iterator;
int ok;
while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
int flags;
if (!S_ISREG(diter->st.st_mode))
continue;
if (diter->basename[0] == '.')
continue;
if (ends_with(diter->basename, ".lock"))
continue;
if (refs_read_ref_full(iter->ref_store,
diter->relative_path, 0,
iter->oid.hash, &flags)) {
error("bad ref for %s", diter->path.buf);
continue;
}
iter->base.refname = diter->relative_path;
iter->base.oid = &iter->oid;
iter->base.flags = flags;
return ITER_OK;
}
iter->dir_iterator = NULL;
if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
ok = ITER_ERROR;
return ok;
}
static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
struct object_id *peeled)
{
die("BUG: ref_iterator_peel() called for reflog_iterator");
}
static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
{
struct files_reflog_iterator *iter =
(struct files_reflog_iterator *)ref_iterator;
int ok = ITER_DONE;
if (iter->dir_iterator)
ok = dir_iterator_abort(iter->dir_iterator);
base_ref_iterator_free(ref_iterator);
return ok;
}
static struct ref_iterator_vtable files_reflog_iterator_vtable = {
files_reflog_iterator_advance,
files_reflog_iterator_peel,
files_reflog_iterator_abort
};
static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ,
"reflog_iterator_begin");
struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
struct ref_iterator *ref_iterator = &iter->base;
struct strbuf sb = STRBUF_INIT;
base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
files_reflog_path(refs, &sb, NULL);
iter->dir_iterator = dir_iterator_begin(sb.buf);
iter->ref_store = ref_store;
strbuf_release(&sb);
return ref_iterator;
}
/*
* If update is a direct update of head_ref (the reference pointed to
* by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
*/
static int split_head_update(struct ref_update *update,
struct ref_transaction *transaction,
const char *head_ref,
struct string_list *affected_refnames,
struct strbuf *err)
{
struct string_list_item *item;
struct ref_update *new_update;
if ((update->flags & REF_LOG_ONLY) ||
(update->flags & REF_ISPRUNING) ||
(update->flags & REF_UPDATE_VIA_HEAD))
return 0;
if (strcmp(update->refname, head_ref))
return 0;
/*
* First make sure that HEAD is not already in the
* transaction. This insertion is O(N) in the transaction
* size, but it happens at most once per transaction.
*/
item = string_list_insert(affected_refnames, "HEAD");
if (item->util) {
/* An entry already existed */
strbuf_addf(err,
"multiple updates for 'HEAD' (including one "
"via its referent '%s') are not allowed",
update->refname);
return TRANSACTION_NAME_CONFLICT;
}
new_update = ref_transaction_add_update(
transaction, "HEAD",
update->flags | REF_LOG_ONLY | REF_NODEREF,
update->new_oid.hash, update->old_oid.hash,
update->msg);
item->util = new_update;
return 0;
}
/*
* update is for a symref that points at referent and doesn't have
* REF_NODEREF set. Split it into two updates:
* - The original update, but with REF_LOG_ONLY and REF_NODEREF set
* - A new, separate update for the referent reference
* Note that the new update will itself be subject to splitting when
* the iteration gets to it.
*/
static int split_symref_update(struct files_ref_store *refs,
struct ref_update *update,
const char *referent,
struct ref_transaction *transaction,
struct string_list *affected_refnames,
struct strbuf *err)
{
struct string_list_item *item;
struct ref_update *new_update;
unsigned int new_flags;
/*
* First make sure that referent is not already in the
* transaction. This insertion is O(N) in the transaction
* size, but it happens at most once per symref in a
* transaction.
*/
item = string_list_insert(affected_refnames, referent);
if (item->util) {
/* An entry already existed */
strbuf_addf(err,
"multiple updates for '%s' (including one "
"via symref '%s') are not allowed",
referent, update->refname);
return TRANSACTION_NAME_CONFLICT;
}
new_flags = update->flags;
if (!strcmp(update->refname, "HEAD")) {
/*
* Record that the new update came via HEAD, so that
* when we process it, split_head_update() doesn't try
* to add another reflog update for HEAD. Note that
* this bit will be propagated if the new_update
* itself needs to be split.
*/
new_flags |= REF_UPDATE_VIA_HEAD;
}
new_update = ref_transaction_add_update(
transaction, referent, new_flags,
update->new_oid.hash, update->old_oid.hash,
update->msg);
new_update->parent_update = update;
/*
* Change the symbolic ref update to log only. Also, it
* doesn't need to check its old SHA-1 value, as that will be
* done when new_update is processed.
*/
update->flags |= REF_LOG_ONLY | REF_NODEREF;
update->flags &= ~REF_HAVE_OLD;
item->util = new_update;
return 0;
}
/*
* Return the refname under which update was originally requested.
*/
static const char *original_update_refname(struct ref_update *update)
{
while (update->parent_update)
update = update->parent_update;
return update->refname;
}
/*
* Check whether the REF_HAVE_OLD and old_oid values stored in update
* are consistent with oid, which is the reference's current value. If
* everything is OK, return 0; otherwise, write an error message to
* err and return -1.
*/
static int check_old_oid(struct ref_update *update, struct object_id *oid,
struct strbuf *err)
{
if (!(update->flags & REF_HAVE_OLD) ||
!oidcmp(oid, &update->old_oid))
return 0;
if (is_null_oid(&update->old_oid))
strbuf_addf(err, "cannot lock ref '%s': "
"reference already exists",
original_update_refname(update));
else if (is_null_oid(oid))
strbuf_addf(err, "cannot lock ref '%s': "
"reference is missing but expected %s",
original_update_refname(update),
oid_to_hex(&update->old_oid));
else
strbuf_addf(err, "cannot lock ref '%s': "
"is at %s but expected %s",
original_update_refname(update),
oid_to_hex(oid),
oid_to_hex(&update->old_oid));
return -1;
}
/*
* Prepare for carrying out update:
* - Lock the reference referred to by update.
* - Read the reference under lock.
* - Check that its old SHA-1 value (if specified) is correct, and in
* any case record it in update->lock->old_oid for later use when
* writing the reflog.
* - If it is a symref update without REF_NODEREF, split it up into a
* REF_LOG_ONLY update of the symref and add a separate update for
* the referent to transaction.
* - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
* update of HEAD.
*/
static int lock_ref_for_update(struct files_ref_store *refs,
struct ref_update *update,
struct ref_transaction *transaction,
const char *head_ref,
struct string_list *affected_refnames,
struct strbuf *err)
{
struct strbuf referent = STRBUF_INIT;
int mustexist = (update->flags & REF_HAVE_OLD) &&
!is_null_oid(&update->old_oid);
int ret;
struct ref_lock *lock;
files_assert_main_repository(refs, "lock_ref_for_update");
if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid))
update->flags |= REF_DELETING;
if (head_ref) {
ret = split_head_update(update, transaction, head_ref,
affected_refnames, err);
if (ret)
return ret;
}
ret = lock_raw_ref(refs, update->refname, mustexist,
affected_refnames, NULL,
&lock, &referent,
&update->type, err);
if (ret) {
char *reason;
reason = strbuf_detach(err, NULL);
strbuf_addf(err, "cannot lock ref '%s': %s",
original_update_refname(update), reason);
free(reason);
return ret;
}
update->backend_data = lock;
if (update->type & REF_ISSYMREF) {
if (update->flags & REF_NODEREF) {
/*
* We won't be reading the referent as part of
* the transaction, so we have to read it here
* to record and possibly check old_sha1:
*/
if (refs_read_ref_full(&refs->base,
referent.buf, 0,
lock->old_oid.hash, NULL)) {
if (update->flags & REF_HAVE_OLD) {
strbuf_addf(err, "cannot lock ref '%s': "
"error reading reference",
original_update_refname(update));
return -1;
}
} else if (check_old_oid(update, &lock->old_oid, err)) {
return TRANSACTION_GENERIC_ERROR;
}
} else {
/*
* Create a new update for the reference this
* symref is pointing at. Also, we will record
* and verify old_sha1 for this update as part
* of processing the split-off update, so we
* don't have to do it here.
*/
ret = split_symref_update(refs