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git/builtin/fsck.c
Jeff King 597f9134de alternates: use a separate scratch space
The alternate_object_database struct uses a single buffer
both for storing the path to the alternate, and as a scratch
buffer for forming object names. This is efficient (since
otherwise we'd end up storing the path twice), but it makes
life hard for callers who just want to know the path to the
alternate. They have to remember to stop reading after
"alt->name - alt->base" bytes, and to subtract one for the
trailing '/'.

It would be much simpler if they could simply access a
NUL-terminated path string. We could encapsulate this in a
function which puts a NUL in the scratch buffer and returns
the string, but that opens up questions about the lifetime
of the result. The first time another caller uses the
alternate, the scratch buffer may get other data tacked onto
it.

Let's instead just store the root path separately from the
scratch buffer. There aren't enough alternates being stored
for the duplicated data to matter for performance, and this
keeps things simple and safe for the callers.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-10-10 13:52:36 -07:00

736 lines
18 KiB
C

#include "builtin.h"
#include "cache.h"
#include "commit.h"
#include "tree.h"
#include "blob.h"
#include "tag.h"
#include "refs.h"
#include "pack.h"
#include "cache-tree.h"
#include "tree-walk.h"
#include "fsck.h"
#include "parse-options.h"
#include "dir.h"
#include "progress.h"
#include "streaming.h"
#include "decorate.h"
#define REACHABLE 0x0001
#define SEEN 0x0002
#define HAS_OBJ 0x0004
static int show_root;
static int show_tags;
static int show_unreachable;
static int include_reflogs = 1;
static int check_full = 1;
static int connectivity_only;
static int check_strict;
static int keep_cache_objects;
static struct fsck_options fsck_walk_options = FSCK_OPTIONS_DEFAULT;
static struct fsck_options fsck_obj_options = FSCK_OPTIONS_DEFAULT;
static struct object_id head_oid;
static const char *head_points_at;
static int errors_found;
static int write_lost_and_found;
static int verbose;
static int show_progress = -1;
static int show_dangling = 1;
static int name_objects;
#define ERROR_OBJECT 01
#define ERROR_REACHABLE 02
#define ERROR_PACK 04
#define ERROR_REFS 010
static const char *describe_object(struct object *obj)
{
static struct strbuf buf = STRBUF_INIT;
char *name = name_objects ?
lookup_decoration(fsck_walk_options.object_names, obj) : NULL;
strbuf_reset(&buf);
strbuf_addstr(&buf, oid_to_hex(&obj->oid));
if (name)
strbuf_addf(&buf, " (%s)", name);
return buf.buf;
}
static int fsck_config(const char *var, const char *value, void *cb)
{
if (strcmp(var, "fsck.skiplist") == 0) {
const char *path;
struct strbuf sb = STRBUF_INIT;
if (git_config_pathname(&path, var, value))
return 1;
strbuf_addf(&sb, "skiplist=%s", path);
free((char *)path);
fsck_set_msg_types(&fsck_obj_options, sb.buf);
strbuf_release(&sb);
return 0;
}
if (skip_prefix(var, "fsck.", &var)) {
fsck_set_msg_type(&fsck_obj_options, var, value);
return 0;
}
return git_default_config(var, value, cb);
}
static void objreport(struct object *obj, const char *msg_type,
const char *err)
{
fprintf(stderr, "%s in %s %s: %s\n",
msg_type, typename(obj->type), describe_object(obj), err);
}
static int objerror(struct object *obj, const char *err)
{
errors_found |= ERROR_OBJECT;
objreport(obj, "error", err);
return -1;
}
static int fsck_error_func(struct fsck_options *o,
struct object *obj, int type, const char *message)
{
objreport(obj, (type == FSCK_WARN) ? "warning" : "error", message);
return (type == FSCK_WARN) ? 0 : 1;
}
static struct object_array pending;
static int mark_object(struct object *obj, int type, void *data, struct fsck_options *options)
{
struct object *parent = data;
/*
* The only case data is NULL or type is OBJ_ANY is when
* mark_object_reachable() calls us. All the callers of
* that function has non-NULL obj hence ...
*/
if (!obj) {
/* ... these references to parent->fld are safe here */
printf("broken link from %7s %s\n",
typename(parent->type), describe_object(parent));
printf("broken link from %7s %s\n",
(type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
errors_found |= ERROR_REACHABLE;
return 1;
}
if (type != OBJ_ANY && obj->type != type)
/* ... and the reference to parent is safe here */
objerror(parent, "wrong object type in link");
if (obj->flags & REACHABLE)
return 0;
obj->flags |= REACHABLE;
if (!(obj->flags & HAS_OBJ)) {
if (parent && !has_object_file(&obj->oid)) {
printf("broken link from %7s %s\n",
typename(parent->type), describe_object(parent));
printf(" to %7s %s\n",
typename(obj->type), describe_object(obj));
errors_found |= ERROR_REACHABLE;
}
return 1;
}
add_object_array(obj, NULL, &pending);
return 0;
}
static void mark_object_reachable(struct object *obj)
{
mark_object(obj, OBJ_ANY, NULL, NULL);
}
static int traverse_one_object(struct object *obj)
{
int result;
struct tree *tree = NULL;
if (obj->type == OBJ_TREE) {
tree = (struct tree *)obj;
if (parse_tree(tree) < 0)
return 1; /* error already displayed */
}
result = fsck_walk(obj, obj, &fsck_walk_options);
if (tree)
free_tree_buffer(tree);
return result;
}
static int traverse_reachable(void)
{
struct progress *progress = NULL;
unsigned int nr = 0;
int result = 0;
if (show_progress)
progress = start_progress_delay(_("Checking connectivity"), 0, 0, 2);
while (pending.nr) {
struct object_array_entry *entry;
struct object *obj;
entry = pending.objects + --pending.nr;
obj = entry->item;
result |= traverse_one_object(obj);
display_progress(progress, ++nr);
}
stop_progress(&progress);
return !!result;
}
static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
{
if (!obj)
return 1;
obj->used = 1;
return 0;
}
/*
* Check a single reachable object
*/
static void check_reachable_object(struct object *obj)
{
/*
* We obviously want the object to be parsed,
* except if it was in a pack-file and we didn't
* do a full fsck
*/
if (!(obj->flags & HAS_OBJ)) {
if (has_sha1_pack(obj->oid.hash))
return; /* it is in pack - forget about it */
if (connectivity_only && has_object_file(&obj->oid))
return;
printf("missing %s %s\n", typename(obj->type),
describe_object(obj));
errors_found |= ERROR_REACHABLE;
return;
}
}
/*
* Check a single unreachable object
*/
static void check_unreachable_object(struct object *obj)
{
/*
* Missing unreachable object? Ignore it. It's not like
* we miss it (since it can't be reached), nor do we want
* to complain about it being unreachable (since it does
* not exist).
*/
if (!obj->parsed)
return;
/*
* Unreachable object that exists? Show it if asked to,
* since this is something that is prunable.
*/
if (show_unreachable) {
printf("unreachable %s %s\n", typename(obj->type),
describe_object(obj));
return;
}
/*
* "!used" means that nothing at all points to it, including
* other unreachable objects. In other words, it's the "tip"
* of some set of unreachable objects, usually a commit that
* got dropped.
*
* Such starting points are more interesting than some random
* set of unreachable objects, so we show them even if the user
* hasn't asked for _all_ unreachable objects. If you have
* deleted a branch by mistake, this is a prime candidate to
* start looking at, for example.
*/
if (!obj->used) {
if (show_dangling)
printf("dangling %s %s\n", typename(obj->type),
describe_object(obj));
if (write_lost_and_found) {
char *filename = git_pathdup("lost-found/%s/%s",
obj->type == OBJ_COMMIT ? "commit" : "other",
describe_object(obj));
FILE *f;
if (safe_create_leading_directories_const(filename)) {
error("Could not create lost-found");
free(filename);
return;
}
if (!(f = fopen(filename, "w")))
die_errno("Could not open '%s'", filename);
if (obj->type == OBJ_BLOB) {
if (stream_blob_to_fd(fileno(f), &obj->oid, NULL, 1))
die_errno("Could not write '%s'", filename);
} else
fprintf(f, "%s\n", describe_object(obj));
if (fclose(f))
die_errno("Could not finish '%s'",
filename);
free(filename);
}
return;
}
/*
* Otherwise? It's there, it's unreachable, and some other unreachable
* object points to it. Ignore it - it's not interesting, and we showed
* all the interesting cases above.
*/
}
static void check_object(struct object *obj)
{
if (verbose)
fprintf(stderr, "Checking %s\n", describe_object(obj));
if (obj->flags & REACHABLE)
check_reachable_object(obj);
else
check_unreachable_object(obj);
}
static void check_connectivity(void)
{
int i, max;
/* Traverse the pending reachable objects */
traverse_reachable();
/* Look up all the requirements, warn about missing objects.. */
max = get_max_object_index();
if (verbose)
fprintf(stderr, "Checking connectivity (%d objects)\n", max);
for (i = 0; i < max; i++) {
struct object *obj = get_indexed_object(i);
if (obj)
check_object(obj);
}
}
static int fsck_obj(struct object *obj)
{
if (obj->flags & SEEN)
return 0;
obj->flags |= SEEN;
if (verbose)
fprintf(stderr, "Checking %s %s\n",
typename(obj->type), describe_object(obj));
if (fsck_walk(obj, NULL, &fsck_obj_options))
objerror(obj, "broken links");
if (fsck_object(obj, NULL, 0, &fsck_obj_options))
return -1;
if (obj->type == OBJ_TREE) {
struct tree *item = (struct tree *) obj;
free_tree_buffer(item);
}
if (obj->type == OBJ_COMMIT) {
struct commit *commit = (struct commit *) obj;
free_commit_buffer(commit);
if (!commit->parents && show_root)
printf("root %s\n", describe_object(&commit->object));
}
if (obj->type == OBJ_TAG) {
struct tag *tag = (struct tag *) obj;
if (show_tags && tag->tagged) {
printf("tagged %s %s", typename(tag->tagged->type),
describe_object(tag->tagged));
printf(" (%s) in %s\n", tag->tag,
describe_object(&tag->object));
}
}
return 0;
}
static int fsck_sha1(const unsigned char *sha1)
{
struct object *obj = parse_object(sha1);
if (!obj) {
errors_found |= ERROR_OBJECT;
return error("%s: object corrupt or missing",
sha1_to_hex(sha1));
}
obj->flags |= HAS_OBJ;
return fsck_obj(obj);
}
static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
unsigned long size, void *buffer, int *eaten)
{
/*
* Note, buffer may be NULL if type is OBJ_BLOB. See
* verify_packfile(), data_valid variable for details.
*/
struct object *obj;
obj = parse_object_buffer(sha1, type, size, buffer, eaten);
if (!obj) {
errors_found |= ERROR_OBJECT;
return error("%s: object corrupt or missing", sha1_to_hex(sha1));
}
obj->flags = HAS_OBJ;
return fsck_obj(obj);
}
static int default_refs;
static void fsck_handle_reflog_sha1(const char *refname, unsigned char *sha1,
unsigned long timestamp)
{
struct object *obj;
if (!is_null_sha1(sha1)) {
obj = lookup_object(sha1);
if (obj) {
if (timestamp && name_objects)
add_decoration(fsck_walk_options.object_names,
obj,
xstrfmt("%s@{%ld}", refname, timestamp));
obj->used = 1;
mark_object_reachable(obj);
} else {
error("%s: invalid reflog entry %s", refname, sha1_to_hex(sha1));
errors_found |= ERROR_REACHABLE;
}
}
}
static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
const char *email, unsigned long timestamp, int tz,
const char *message, void *cb_data)
{
const char *refname = cb_data;
if (verbose)
fprintf(stderr, "Checking reflog %s->%s\n",
sha1_to_hex(osha1), sha1_to_hex(nsha1));
fsck_handle_reflog_sha1(refname, osha1, 0);
fsck_handle_reflog_sha1(refname, nsha1, timestamp);
return 0;
}
static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
int flag, void *cb_data)
{
for_each_reflog_ent(logname, fsck_handle_reflog_ent, (void *)logname);
return 0;
}
static int fsck_handle_ref(const char *refname, const struct object_id *oid,
int flag, void *cb_data)
{
struct object *obj;
obj = parse_object(oid->hash);
if (!obj) {
error("%s: invalid sha1 pointer %s", refname, oid_to_hex(oid));
errors_found |= ERROR_REACHABLE;
/* We'll continue with the rest despite the error.. */
return 0;
}
if (obj->type != OBJ_COMMIT && is_branch(refname)) {
error("%s: not a commit", refname);
errors_found |= ERROR_REFS;
}
default_refs++;
obj->used = 1;
if (name_objects)
add_decoration(fsck_walk_options.object_names,
obj, xstrdup(refname));
mark_object_reachable(obj);
return 0;
}
static void get_default_heads(void)
{
if (head_points_at && !is_null_oid(&head_oid))
fsck_handle_ref("HEAD", &head_oid, 0, NULL);
for_each_rawref(fsck_handle_ref, NULL);
if (include_reflogs)
for_each_reflog(fsck_handle_reflog, NULL);
/*
* Not having any default heads isn't really fatal, but
* it does mean that "--unreachable" no longer makes any
* sense (since in this case everything will obviously
* be unreachable by definition.
*
* Showing dangling objects is valid, though (as those
* dangling objects are likely lost heads).
*
* So we just print a warning about it, and clear the
* "show_unreachable" flag.
*/
if (!default_refs) {
fprintf(stderr, "notice: No default references\n");
show_unreachable = 0;
}
}
static int fsck_loose(const unsigned char *sha1, const char *path, void *data)
{
if (fsck_sha1(sha1))
errors_found |= ERROR_OBJECT;
return 0;
}
static int fsck_cruft(const char *basename, const char *path, void *data)
{
if (!starts_with(basename, "tmp_obj_"))
fprintf(stderr, "bad sha1 file: %s\n", path);
return 0;
}
static int fsck_subdir(int nr, const char *path, void *progress)
{
display_progress(progress, nr + 1);
return 0;
}
static void fsck_object_dir(const char *path)
{
struct progress *progress = NULL;
if (verbose)
fprintf(stderr, "Checking object directory\n");
if (show_progress)
progress = start_progress(_("Checking object directories"), 256);
for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
progress);
display_progress(progress, 256);
stop_progress(&progress);
}
static int fsck_head_link(void)
{
int null_is_error = 0;
if (verbose)
fprintf(stderr, "Checking HEAD link\n");
head_points_at = resolve_ref_unsafe("HEAD", 0, head_oid.hash, NULL);
if (!head_points_at) {
errors_found |= ERROR_REFS;
return error("Invalid HEAD");
}
if (!strcmp(head_points_at, "HEAD"))
/* detached HEAD */
null_is_error = 1;
else if (!starts_with(head_points_at, "refs/heads/")) {
errors_found |= ERROR_REFS;
return error("HEAD points to something strange (%s)",
head_points_at);
}
if (is_null_oid(&head_oid)) {
if (null_is_error) {
errors_found |= ERROR_REFS;
return error("HEAD: detached HEAD points at nothing");
}
fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
head_points_at + 11);
}
return 0;
}
static int fsck_cache_tree(struct cache_tree *it)
{
int i;
int err = 0;
if (verbose)
fprintf(stderr, "Checking cache tree\n");
if (0 <= it->entry_count) {
struct object *obj = parse_object(it->sha1);
if (!obj) {
error("%s: invalid sha1 pointer in cache-tree",
sha1_to_hex(it->sha1));
errors_found |= ERROR_REFS;
return 1;
}
obj->used = 1;
if (name_objects)
add_decoration(fsck_walk_options.object_names,
obj, xstrdup(":"));
mark_object_reachable(obj);
if (obj->type != OBJ_TREE)
err |= objerror(obj, "non-tree in cache-tree");
}
for (i = 0; i < it->subtree_nr; i++)
err |= fsck_cache_tree(it->down[i]->cache_tree);
return err;
}
static char const * const fsck_usage[] = {
N_("git fsck [<options>] [<object>...]"),
NULL
};
static struct option fsck_opts[] = {
OPT__VERBOSE(&verbose, N_("be verbose")),
OPT_BOOL(0, "unreachable", &show_unreachable, N_("show unreachable objects")),
OPT_BOOL(0, "dangling", &show_dangling, N_("show dangling objects")),
OPT_BOOL(0, "tags", &show_tags, N_("report tags")),
OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),
OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
OPT_BOOL(0, "lost-found", &write_lost_and_found,
N_("write dangling objects in .git/lost-found")),
OPT_BOOL(0, "progress", &show_progress, N_("show progress")),
OPT_BOOL(0, "name-objects", &name_objects, N_("show verbose names for reachable objects")),
OPT_END(),
};
int cmd_fsck(int argc, const char **argv, const char *prefix)
{
int i, heads;
struct alternate_object_database *alt;
errors_found = 0;
check_replace_refs = 0;
argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
fsck_walk_options.walk = mark_object;
fsck_obj_options.walk = mark_used;
fsck_obj_options.error_func = fsck_error_func;
if (check_strict)
fsck_obj_options.strict = 1;
if (show_progress == -1)
show_progress = isatty(2);
if (verbose)
show_progress = 0;
if (write_lost_and_found) {
check_full = 1;
include_reflogs = 0;
}
if (name_objects)
fsck_walk_options.object_names =
xcalloc(1, sizeof(struct decoration));
git_config(fsck_config, NULL);
fsck_head_link();
if (!connectivity_only) {
fsck_object_dir(get_object_directory());
prepare_alt_odb();
for (alt = alt_odb_list; alt; alt = alt->next)
fsck_object_dir(alt->path);
}
if (check_full) {
struct packed_git *p;
uint32_t total = 0, count = 0;
struct progress *progress = NULL;
prepare_packed_git();
if (show_progress) {
for (p = packed_git; p; p = p->next) {
if (open_pack_index(p))
continue;
total += p->num_objects;
}
progress = start_progress(_("Checking objects"), total);
}
for (p = packed_git; p; p = p->next) {
/* verify gives error messages itself */
if (verify_pack(p, fsck_obj_buffer,
progress, count))
errors_found |= ERROR_PACK;
count += p->num_objects;
}
stop_progress(&progress);
}
heads = 0;
for (i = 0; i < argc; i++) {
const char *arg = argv[i];
unsigned char sha1[20];
if (!get_sha1(arg, sha1)) {
struct object *obj = lookup_object(sha1);
/* Error is printed by lookup_object(). */
if (!obj)
continue;
obj->used = 1;
if (name_objects)
add_decoration(fsck_walk_options.object_names,
obj, xstrdup(arg));
mark_object_reachable(obj);
heads++;
continue;
}
error("invalid parameter: expected sha1, got '%s'", arg);
}
/*
* If we've not been given any explicit head information, do the
* default ones from .git/refs. We also consider the index file
* in this case (ie this implies --cache).
*/
if (!heads) {
get_default_heads();
keep_cache_objects = 1;
}
if (keep_cache_objects) {
read_cache();
for (i = 0; i < active_nr; i++) {
unsigned int mode;
struct blob *blob;
struct object *obj;
mode = active_cache[i]->ce_mode;
if (S_ISGITLINK(mode))
continue;
blob = lookup_blob(active_cache[i]->oid.hash);
if (!blob)
continue;
obj = &blob->object;
obj->used = 1;
if (name_objects)
add_decoration(fsck_walk_options.object_names,
obj,
xstrfmt(":%s", active_cache[i]->name));
mark_object_reachable(obj);
}
if (active_cache_tree)
fsck_cache_tree(active_cache_tree);
}
check_connectivity();
return errors_found;
}