git/refs.h
Ronnie Sahlberg d0f810f0bc refs.c: allow listing and deleting badly named refs
We currently do not handle badly named refs well:

  $ cp .git/refs/heads/master .git/refs/heads/master.....@\*@\\.
  $ git branch
    fatal: Reference has invalid format: 'refs/heads/master.....@*@\.'
  $ git branch -D master.....@\*@\\.
    error: branch 'master.....@*@\.' not found.

Users cannot recover from a badly named ref without manually finding
and deleting the loose ref file or appropriate line in packed-refs.
Making that easier will make it easier to tweak the ref naming rules
in the future, for example to forbid shell metacharacters like '`'
and '"', without putting people in a state that is hard to get out of.

So allow "branch --list" to show these refs and allow "branch -d/-D"
and "update-ref -d" to delete them.  Other commands (for example to
rename refs) will continue to not handle these refs but can be changed
in later patches.

Details:

In resolving functions, refuse to resolve refs that don't pass the
git-check-ref-format(1) check unless the new RESOLVE_REF_ALLOW_BAD_NAME
flag is passed.  Even with RESOLVE_REF_ALLOW_BAD_NAME, refuse to
resolve refs that escape the refs/ directory and do not match the
pattern [A-Z_]* (think "HEAD" and "MERGE_HEAD").

In locking functions, refuse to act on badly named refs unless they
are being deleted and either are in the refs/ directory or match [A-Z_]*.

Just like other invalid refs, flag resolved, badly named refs with the
REF_ISBROKEN flag, treat them as resolving to null_sha1, and skip them
in all iteration functions except for for_each_rawref.

Flag badly named refs (but not symrefs pointing to badly named refs)
with a REF_BAD_NAME flag to make it easier for future callers to
notice and handle them specially.  For example, in a later patch
for-each-ref will use this flag to detect refs whose names can confuse
callers parsing for-each-ref output.

In the transaction API, refuse to create or update badly named refs,
but allow deleting them (unless they try to escape refs/ and don't match
[A-Z_]*).

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 10:47:26 -07:00

357 lines
13 KiB
C

#ifndef REFS_H
#define REFS_H
struct ref_lock {
char *ref_name;
char *orig_ref_name;
struct lock_file *lk;
unsigned char old_sha1[20];
int lock_fd;
int force_write;
};
/*
* A ref_transaction represents a collection of ref updates
* that should succeed or fail together.
*
* Calling sequence
* ----------------
* - Allocate and initialize a `struct ref_transaction` by calling
* `ref_transaction_begin()`.
*
* - List intended ref updates by calling functions like
* `ref_transaction_update()` and `ref_transaction_create()`.
*
* - Call `ref_transaction_commit()` to execute the transaction.
* If this succeeds, the ref updates will have taken place and
* the transaction cannot be rolled back.
*
* - At any time call `ref_transaction_free()` to discard the
* transaction and free associated resources. In particular,
* this rolls back the transaction if it has not been
* successfully committed.
*
* Error handling
* --------------
*
* On error, transaction functions append a message about what
* went wrong to the 'err' argument. The message mentions what
* ref was being updated (if any) when the error occurred so it
* can be passed to 'die' or 'error' as-is.
*
* The message is appended to err without first clearing err.
* err will not be '\n' terminated.
*/
struct ref_transaction;
/*
* Bit values set in the flags argument passed to each_ref_fn():
*/
/* Reference is a symbolic reference. */
#define REF_ISSYMREF 0x01
/* Reference is a packed reference. */
#define REF_ISPACKED 0x02
/*
* Reference cannot be resolved to an object name: dangling symbolic
* reference (directly or indirectly), corrupt reference file,
* reference exists but name is bad, or symbolic reference refers to
* ill-formatted reference name.
*/
#define REF_ISBROKEN 0x04
/*
* Reference name is not well formed.
*
* See git-check-ref-format(1) for the definition of well formed ref names.
*/
#define REF_BAD_NAME 0x08
/*
* The signature for the callback function for the for_each_*()
* functions below. The memory pointed to by the refname and sha1
* arguments is only guaranteed to be valid for the duration of a
* single callback invocation.
*/
typedef int each_ref_fn(const char *refname,
const unsigned char *sha1, int flags, void *cb_data);
/*
* The following functions invoke the specified callback function for
* each reference indicated. If the function ever returns a nonzero
* value, stop the iteration and return that value. Please note that
* it is not safe to modify references while an iteration is in
* progress, unless the same callback function invocation that
* modifies the reference also returns a nonzero value to immediately
* stop the iteration.
*/
extern int head_ref(each_ref_fn, void *);
extern int for_each_ref(each_ref_fn, void *);
extern int for_each_ref_in(const char *, each_ref_fn, void *);
extern int for_each_tag_ref(each_ref_fn, void *);
extern int for_each_branch_ref(each_ref_fn, void *);
extern int for_each_remote_ref(each_ref_fn, void *);
extern int for_each_replace_ref(each_ref_fn, void *);
extern int for_each_glob_ref(each_ref_fn, const char *pattern, void *);
extern int for_each_glob_ref_in(each_ref_fn, const char *pattern, const char* prefix, void *);
extern int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int for_each_ref_in_submodule(const char *submodule, const char *prefix,
each_ref_fn fn, void *cb_data);
extern int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int head_ref_namespaced(each_ref_fn fn, void *cb_data);
extern int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);
static inline const char *has_glob_specials(const char *pattern)
{
return strpbrk(pattern, "?*[");
}
/* can be used to learn about broken ref and symref */
extern int for_each_rawref(each_ref_fn, void *);
extern void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname);
extern void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames);
/*
* Lock the packed-refs file for writing. Flags is passed to
* hold_lock_file_for_update(). Return 0 on success.
* Errno is set to something meaningful on error.
*/
extern int lock_packed_refs(int flags);
/*
* 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().
*/
extern void add_packed_ref(const char *refname, const unsigned char *sha1);
/*
* 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.
* Sets errno to something meaningful on error.
*/
extern int commit_packed_refs(void);
/*
* 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.)
*/
extern void rollback_packed_refs(void);
/*
* Flags for controlling behaviour of pack_refs()
* PACK_REFS_PRUNE: Prune loose refs after packing
* PACK_REFS_ALL: Pack _all_ refs, not just tags and already packed refs
*/
#define PACK_REFS_PRUNE 0x0001
#define PACK_REFS_ALL 0x0002
/*
* Write a packed-refs file for the current repository.
* flags: Combination of the above PACK_REFS_* flags.
*/
int pack_refs(unsigned int flags);
extern int repack_without_refs(const char **refnames, int n,
struct strbuf *err);
extern int ref_exists(const char *);
extern int is_branch(const char *refname);
/*
* If refname is a non-symbolic reference that refers to a tag object,
* and the tag can be (recursively) dereferenced to a non-tag object,
* store the SHA1 of the referred-to object to sha1 and return 0. If
* any of these conditions are not met, return a non-zero value.
* Symbolic references are considered unpeelable, even if they
* ultimately resolve to a peelable tag.
*/
extern int peel_ref(const char *refname, unsigned char *sha1);
/*
* Flags controlling lock_any_ref_for_update(), ref_transaction_update(),
* ref_transaction_create(), etc.
* REF_NODEREF: act on the ref directly, instead of dereferencing
* symbolic references.
* REF_DELETING: tolerate broken refs
*
* Flags >= 0x100 are reserved for internal use.
*/
#define REF_NODEREF 0x01
#define REF_DELETING 0x02
/*
* This function sets errno to something meaningful on failure.
*/
extern struct ref_lock *lock_any_ref_for_update(const char *refname,
const unsigned char *old_sha1,
int flags, int *type_p);
/** Close the file descriptor owned by a lock and return the status */
extern int close_ref(struct ref_lock *lock);
/** Close and commit the ref locked by the lock */
extern int commit_ref(struct ref_lock *lock);
/** Release any lock taken but not written. **/
extern void unlock_ref(struct ref_lock *lock);
/*
* Setup reflog before using. Set errno to something meaningful on failure.
*/
int log_ref_setup(const char *refname, char *logfile, int bufsize);
/** Reads log for the value of ref during at_time. **/
extern int read_ref_at(const char *refname, unsigned int flags,
unsigned long at_time, int cnt,
unsigned char *sha1, char **msg,
unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);
/** Check if a particular reflog exists */
extern int reflog_exists(const char *refname);
/** Delete a reflog */
extern int delete_reflog(const char *refname);
/* iterate over reflog entries */
typedef int each_reflog_ent_fn(unsigned char *osha1, unsigned char *nsha1, const char *, unsigned long, int, const char *, void *);
int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
/*
* Calls the specified function for each reflog file until it returns nonzero,
* and returns the value
*/
extern int for_each_reflog(each_ref_fn, void *);
#define REFNAME_ALLOW_ONELEVEL 1
#define REFNAME_REFSPEC_PATTERN 2
/*
* Return 0 iff refname has the correct format for a refname according
* to the rules described in Documentation/git-check-ref-format.txt.
* If REFNAME_ALLOW_ONELEVEL is set in flags, then accept one-level
* reference names. If REFNAME_REFSPEC_PATTERN is set in flags, then
* allow a "*" wildcard character in place of one of the name
* components. No leading or repeated slashes are accepted.
*/
extern int check_refname_format(const char *refname, int flags);
extern const char *prettify_refname(const char *refname);
extern char *shorten_unambiguous_ref(const char *refname, int strict);
/** rename ref, return 0 on success **/
extern int rename_ref(const char *oldref, const char *newref, const char *logmsg);
/**
* Resolve refname in the nested "gitlink" repository that is located
* at path. If the resolution is successful, return 0 and set sha1 to
* the name of the object; otherwise, return a non-zero value.
*/
extern int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1);
enum action_on_err {
UPDATE_REFS_MSG_ON_ERR,
UPDATE_REFS_DIE_ON_ERR,
UPDATE_REFS_QUIET_ON_ERR
};
/*
* Begin a reference transaction. The reference transaction must
* be freed by calling ref_transaction_free().
*/
struct ref_transaction *ref_transaction_begin(struct strbuf *err);
/*
* The following functions add a reference check or update to a
* ref_transaction. In all of them, refname is the name of the
* reference to be affected. The functions make internal copies of
* refname and msg, so the caller retains ownership of these parameters.
* flags can be REF_NODEREF; it is passed to update_ref_lock().
*/
/*
* Add a reference update to transaction. new_sha1 is the value that
* the reference should have after the update, or zeros if it should
* be deleted. If have_old is true, then old_sha1 holds the value
* that the reference should have had before the update, or zeros if
* it must not have existed beforehand.
* Function returns 0 on success and non-zero on failure. A failure to update
* means that the transaction as a whole has failed and will need to be
* rolled back.
*/
int ref_transaction_update(struct ref_transaction *transaction,
const char *refname,
const unsigned char *new_sha1,
const unsigned char *old_sha1,
int flags, int have_old, const char *msg,
struct strbuf *err);
/*
* Add a reference creation to transaction. new_sha1 is the value
* that the reference should have after the update; it must not be the
* null SHA-1. It is verified that the reference does not exist
* already.
* Function returns 0 on success and non-zero on failure. A failure to create
* means that the transaction as a whole has failed and will need to be
* rolled back.
*/
int ref_transaction_create(struct ref_transaction *transaction,
const char *refname,
const unsigned char *new_sha1,
int flags, const char *msg,
struct strbuf *err);
/*
* Add a reference deletion to transaction. If have_old is true, then
* old_sha1 holds the value that the reference should have had before
* the update (which must not be the null SHA-1).
* Function returns 0 on success and non-zero on failure. A failure to delete
* means that the transaction as a whole has failed and will need to be
* rolled back.
*/
int ref_transaction_delete(struct ref_transaction *transaction,
const char *refname,
const unsigned char *old_sha1,
int flags, int have_old, const char *msg,
struct strbuf *err);
/*
* Commit all of the changes that have been queued in transaction, as
* atomically as possible.
*
* Returns 0 for success, or one of the below error codes for errors.
*/
/* Naming conflict (for example, the ref names A and A/B conflict). */
#define TRANSACTION_NAME_CONFLICT -1
/* All other errors. */
#define TRANSACTION_GENERIC_ERROR -2
int ref_transaction_commit(struct ref_transaction *transaction,
struct strbuf *err);
/*
* Free an existing transaction and all associated data.
*/
void ref_transaction_free(struct ref_transaction *transaction);
/** Lock a ref and then write its file */
int update_ref(const char *action, const char *refname,
const unsigned char *sha1, const unsigned char *oldval,
int flags, enum action_on_err onerr);
extern int parse_hide_refs_config(const char *var, const char *value, const char *);
extern int ref_is_hidden(const char *);
#endif /* REFS_H */