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Commit 58d06cf1 by Vicent Marti
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Rewrite the Pack backend 

The new pack backend is an adaptation of the original git.git code in
`sha1_file.c`. It's slightly faster than the previous version and
severely less memory-hungry.

The call-stack of a normal pack backend query has been properly
documented in the top of the header for future reference. And by
properly I mean with ASCII diagrams 'n shit.
parent 71db842f
Showing with 1042 additions and 842 deletions
src/odb_pack.c
......@@ -33,503 +33,625 @@
#include "git2/odb_backend.h"
/** First 4 bytes of a pack-*.idx file header.
*
* Note this header exists only in idx v2 and later. The idx v1
* file format does not have a magic sequence at the front, and
* must be detected by the first four bytes *not* being this value
* and the first 8 bytes matching the following expression:
#define DEFAULT_WINDOW_SIZE \
(sizeof(void*) >= 8 \
? 1 * 1024 * 1024 * 1024 \
: 32 * 1024 * 1024)
#define DEFAULT_MAPPED_LIMIT \
((1024L * 1024L) * (sizeof(void*) >= 8 ? 8192 : 256))
#define PACK_SIGNATURE 0x5041434b /* "PACK" */
#define PACK_VERSION 2
#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
struct pack_header {
uint32_t hdr_signature;
uint32_t hdr_version;
uint32_t hdr_entries;
};
/*
* The first four bytes of index formats later than version 1 should
* start with this signature, as all older git binaries would find this
* value illegal and abort reading the file.
*
* uint32_t *fanout = ... the file data at offset 0 ...
* ntohl(fanout[0]) < ntohl(fanout[1])
* This is the case because the number of objects in a packfile
* cannot exceed 1,431,660,000 as every object would need at least
* 3 bytes of data and the overall packfile cannot exceed 4 GiB with
* version 1 of the index file due to the offsets limited to 32 bits.
* Clearly the signature exceeds this maximum.
*
* The value chosen here for PACK_TOC is such that the above
* cannot be true for an idx v1 file.
* Very old git binaries will also compare the first 4 bytes to the
* next 4 bytes in the index and abort with a "non-monotonic index"
* error if the second 4 byte word is smaller than the first 4
* byte word. This would be true in the proposed future index
* format as idx_signature would be greater than idx_version.
*/
#define PACK_TOC 0xff744f63 /* -1tOc */
#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */
/** First 4 bytes of a pack-*.pack file header. */
#define PACK_SIG 0x5041434b /* PACK */
struct pack_idx_header {
uint32_t idx_signature;
uint32_t idx_version;
};
#define GIT_PACK_NAME_MAX (5 + 40 + 1)
struct pack_window {
struct pack_window *next;
git_map window_map;
off_t offset;
unsigned int last_used;
unsigned int inuse_cnt;
};
struct pack_backend;
struct pack_file {
struct pack_window *windows;
off_t pack_size;
typedef struct {
uint32_t n;
unsigned char *oid;
git_off_t offset;
git_off_t size;
} index_entry;
git_map index_map;
typedef struct { /* '.pack' file header */
uint32_t sig; /* PACK_SIG */
uint32_t ver; /* pack version */
uint32_t cnt; /* object count */
} pack_hdr;
uint32_t num_objects;
uint32_t num_bad_objects;
git_oid *bad_object_sha1; /* array of git_oid */
typedef struct git_pack {
struct pack_backend *backend;
git_lck lock;
/** Functions to access idx_map. */
int (*idx_search)(
uint32_t *,
struct git_pack *,
const git_oid *);
int (*idx_search_offset)(
uint32_t *,
struct git_pack *,
git_off_t);
int (*idx_get)(
index_entry *,
struct git_pack *,
uint32_t n);
/** The .idx file, mapped into memory. */
git_file idx_fd;
git_map idx_map;
uint32_t *im_fanout;
unsigned char *im_oid;
uint32_t *im_crc;
uint32_t *im_offset32;
uint32_t *im_offset64;
uint32_t *im_off_idx;
uint32_t *im_off_next;
/** Number of objects in this pack. */
uint32_t obj_cnt;
/** File descriptor for the .pack file. */
git_file pack_fd;
/** Memory map of the pack's contents */
git_map pack_map;
/** The size of the .pack file. */
git_off_t pack_size;
/** The mtime of the .pack file. */
time_t pack_mtime;
/** Number of git_packlist we appear in. */
unsigned int refcnt;
/** Number of active users of the idx_map data. */
unsigned int idxcnt;
unsigned
invalid:1 /* the pack is unable to be read by libgit2 */
;
/** Name of the pack file(s), without extension ("pack-abc"). */
char pack_name[GIT_PACK_NAME_MAX];
} git_pack;
typedef struct {
size_t n_packs;
unsigned int refcnt;
git_pack *packs[GIT_FLEX_ARRAY];
} git_packlist;
typedef struct pack_backend {
git_odb_backend parent;
int index_version;
time_t mtime;
int pack_fd;
unsigned pack_local:1, pack_keep:1;
git_oid sha1;
git_lck lock;
char *objects_dir;
git_packlist *packlist;
} pack_backend;
/* something like ".git/objects/pack/xxxxx.pack" */
char pack_name[GIT_FLEX_ARRAY]; /* more */
};
struct pack_entry {
off_t offset;
git_oid sha1;
struct pack_file *p;
};
typedef struct pack_location {
git_pack *ptr;
uint32_t n;
} pack_location;
struct pack__dirent {
struct pack_backend *backend;
int is_pack_local;
};
static int pack_stat(git_pack *p);
static int pack_openidx(git_pack *p);
static void pack_decidx(git_pack *p);
static int read_pack_hdr(pack_hdr *out, git_file fd);
static int check_pack_hdr(git_pack *p);
static int check_pack_sha1(git_pack *p);
static int open_pack(git_pack *p);
struct pack_backend {
git_odb_backend parent;
git_vector packs;
struct pack_file *last_found;
size_t window_size; /* needs default value */
static int pack_openidx_map(git_pack *p);
static int pack_openidx_v1(git_pack *p);
static int pack_openidx_v2(git_pack *p);
size_t mapped_limit; /* needs default value */
size_t peak_mapped;
size_t mapped;
size_t used_ctr;
GIT_INLINE(uint32_t) decode32(void *b)
{
return ntohl(*((uint32_t *)b));
}
unsigned int peak_open_windows;
unsigned int open_windows;
unsigned int mmap_calls;
};
/**
* The wonderful tale of a Packed Object lookup query
* ===================================================
* A riveting and epic story of epicness and ASCII
* art, presented by yours truly,
* Sir Vicent of Marti
*
*
* Chapter 1: Once upon a time...
* Initialization of the Pack Backend
* --------------------------------------------------
*
* # git_odb_backend_pack
* | Creates the pack backend structure, initializes the
* | callback pointers to our default read() and exist() methods,
* | and tries to preload all the known packfiles in the ODB.
* |
* |-# packfile_load_all
* | Tries to find the `pack` folder, if it exists. ODBs without
* | a pack folder are ignored altogether. If there's a `pack` folder
* | we run a `dirent` callback through every file in the pack folder
* | to find our packfiles. The packfiles are then sorted according
* | to a sorting callback.
* |
* |-# packfile_load__cb
* | | This callback is called from `dirent` with every single file
* | | inside the pack folder. We find the packs by actually locating
* | | their index (ends in ".idx"). From that index, we verify that
* | | the corresponding packfile exists and is valid, and if so, we
* | | add it to the pack list.
* | |
* | |-# packfile_check
* | Make sure that there's a packfile to back this index, and store
* | some very basic information regarding the packfile itself,
* | such as the full path, the size, and the modification time.
* | We don't actually open the packfile to check for internal consistency.
* |
* |-# packfile_sort__cb
* Sort all the preloaded packs according to some specific criteria:
* we prioritize the "newer" packs because it's more likely they
* contain the objects we are looking for, and we prioritize local
* packs over remote ones.
*
*
*
* Chapter 2: To be, or not to be...
* A standard packed `exist` query for an OID
* --------------------------------------------------
*
* # pack_backend__exists
* | Check if the given SHA1 oid exists in any of the packs
* | that have been loaded for our ODB.
* |
* |-# pack_entry_find
* | Iterate through all the packs that have been preloaded
* | (starting by the pack where the latest object was found)
* | to try to find the OID in one of them.
* |
* |-# pack_entry_find1
* | Check the index of an individual pack to see if the SHA1
* | OID can be found. If we can find the offset to that SHA1
* | inside of the index, that means the object is contained
* | inside of the packfile and we can stop searching.
* | Before returning, we verify that the packfile behing the
* | index we are searching still exists on disk.
* |
* |-# pack_entry_find_offset
* | | Mmap the actual index file to disk if it hasn't been opened
* | | yet, and run a binary search through it to find the OID.
* | | See <http://book.git-scm.com/7_the_packfile.html> for specifics
* | | on the Packfile Index format and how do we find entries in it.
* | |
* | |-# pack_index_open
* | | Guess the name of the index based on the full path to the
* | | packfile, open it and verify its contents. Only if the index
* | | has not been opened already.
* | |
* | |-# pack_index_check
* | Mmap the index file and do a quick run through the header
* | to guess the index version (right now we support v1 and v2),
* | and to verify that the size of the index makes sense.
* |
* |-# packfile_open
* See `packfile_open` in Chapter 3
*
*
*
* Chapter 3: The neverending story...
* A standard packed `lookup` query for an OID
* --------------------------------------------------
* TODO
*
*/
GIT_INLINE(uint64_t) decode64(void *b)
{
uint32_t *p = b;
return (((uint64_t)ntohl(p[0])) << 32) | ntohl(p[1]);
}
/***********************************************************
*
* PACKFILE FUNCTIONS
*
* Locate, open and access the contents of a packfile
* FORWARD DECLARATIONS
*
***********************************************************/
static int pack_stat(git_pack *p)
{
char pb[GIT_PATH_MAX];
struct stat sb;
static void pack_window_free_all(struct pack_backend *backend, struct pack_file *p);
static int pack_window_contains(struct pack_window *win, off_t offset);
if (git__fmt(pb, sizeof(pb), "%s/pack/%s.pack",
p->backend->objects_dir,
p->pack_name) < 0)
return GIT_ERROR;
static void pack_window_scan_lru(struct pack_file *p, struct pack_file **lru_p,
struct pack_window **lru_w, struct pack_window **lru_l);
if (gitfo_stat(pb, &sb) || !S_ISREG(sb.st_mode))
return GIT_ERROR;
static int pack_window_close_lru( struct pack_backend *backend,
struct pack_file *current, git_file keep_fd);
if (sb.st_size < (3 * 4 + GIT_OID_RAWSZ))
return GIT_ERROR;
static void pack_window_close(struct pack_window **w_cursor);
p->pack_size = sb.st_size;
p->pack_mtime = sb.st_mtime;
static unsigned char *pack_window_open( struct pack_backend *backend,
struct pack_file *p, struct pack_window **w_cursor, off_t offset,
unsigned int *left);
return GIT_SUCCESS;
}
static int packfile_sort__cb(const void *a_, const void *b_);
static int pack_openidx(git_pack *p)
{
gitlck_lock(&p->lock);
static void pack_index_free(struct pack_file *p);
if (p->invalid) {
gitlck_unlock(&p->lock);
return GIT_ERROR;
}
static int pack_index_check(const char *path, struct pack_file *p);
static int pack_index_open(struct pack_file *p);
if (++p->idxcnt == 1 && !p->idx_search) {
int status, version;
uint32_t *data;
static struct pack_file *packfile_alloc(int extra);
static int packfile_open(struct pack_file *p);
static int packfile_check(struct pack_file **pack_out, const char *path, int local);
static int packfile_load__cb(void *_data, char *path);
static int packfile_load_all(struct pack_backend *backend, const char *odb_path, int local);
if (pack_stat(p) || pack_openidx_map(p)) {
p->invalid = 1;
p->idxcnt--;
gitlck_unlock(&p->lock);
return GIT_ERROR;
}
data = p->idx_map.data;
status = GIT_SUCCESS;
version = 1;
static off_t nth_packed_object_offset(const struct pack_file *p, uint32_t n);
if (decode32(&data[0]) == PACK_TOC)
version = decode32(&data[1]);
static int pack_entry_find_offset(off_t *offset_out,
struct pack_file *p, const git_oid *oid);
switch (version) {
case 1:
status = pack_openidx_v1(p);
break;
case 2:
status = pack_openidx_v2(p);
break;
default:
status = GIT_ERROR;
}
static int pack_entry_find1(struct pack_entry *e,
struct pack_file *p, const git_oid *oid);
if (status != GIT_SUCCESS) {
gitfo_free_map(&p->idx_map);
p->invalid = 1;
p->idxcnt--;
gitlck_unlock(&p->lock);
return status;
}
}
static int pack_entry_find(struct pack_entry *e,
struct pack_backend *backend, const git_oid *oid);
gitlck_unlock(&p->lock);
return GIT_SUCCESS;
}
static off_t get_delta_base(struct pack_backend *backend,
struct pack_file *p, struct pack_window **w_curs,
off_t *curpos, git_otype type,
off_t delta_obj_offset);
static void pack_decidx(git_pack *p)
{
gitlck_lock(&p->lock);
p->idxcnt--;
gitlck_unlock(&p->lock);
}
static unsigned long packfile_unpack_header1(
size_t *sizep,
git_otype *type,
const unsigned char *buf,
unsigned long len);
static int read_pack_hdr(pack_hdr *out, git_file fd)
{
pack_hdr hdr;
static int packfile_unpack_header(
size_t *size_p,
git_otype *type_p,
struct pack_backend *backend,
struct pack_file *p,
struct pack_window **w_curs,
off_t *curpos);
static int packfile_unpack_compressed(
git_rawobj *obj,
struct pack_backend *backend,
struct pack_file *p,
struct pack_window **w_curs,
off_t curpos,
size_t size,
git_otype type);
static int packfile_unpack_delta(
git_rawobj *obj,
struct pack_backend *backend,
struct pack_file *p,
struct pack_window **w_curs,
off_t curpos,
size_t delta_size,
git_otype delta_type,
off_t obj_offset);
static int packfile_unpack(git_rawobj *obj, struct pack_backend *backend,
struct pack_file *p, off_t obj_offset);
if (gitfo_read(fd, &hdr, sizeof(hdr)))
return GIT_ERROR;
out->sig = decode32(&hdr.sig);
out->ver = decode32(&hdr.ver);
out->cnt = decode32(&hdr.cnt);
return GIT_SUCCESS;
}
static int check_pack_hdr(git_pack *p)
/***********************************************************
*
* PACK WINDOW MANAGEMENT
*
***********************************************************/
void pack_window_free_all(struct pack_backend *backend, struct pack_file *p)
{
pack_hdr hdr;
while (p->windows) {
struct pack_window *w = p->windows;
assert(w->inuse_cnt == 0);
if (read_pack_hdr(&hdr, p->pack_fd))
return GIT_ERROR;
backend->mapped -= w->window_map.len;
backend->open_windows--;
if (hdr.sig != PACK_SIG
|| (hdr.ver != 2 && hdr.ver != 3)
|| hdr.cnt != p->obj_cnt)
return GIT_ERROR;
gitfo_free_map(&w->window_map);
return GIT_SUCCESS;
p->windows = w->next;
free(w);
}
}
static int check_pack_sha1(git_pack *p)
GIT_INLINE(int) pack_window_contains(struct pack_window *win, off_t offset)
{
unsigned char *data = p->idx_map.data;
git_off_t pack_sha1_off = p->pack_size - GIT_OID_RAWSZ;
size_t idx_pack_sha1_off = p->idx_map.len - 2 * GIT_OID_RAWSZ;
git_oid pack_id, idx_pack_id;
/* We must promise at least 20 bytes (one hash) after the
* offset is available from this window, otherwise the offset
* is not actually in this window and a different window (which
* has that one hash excess) must be used. This is to support
* the object header and delta base parsing routines below.
*/
off_t win_off = win->offset;
return win_off <= offset
&& (offset + 20) <= (off_t)(win_off + win->window_map.len);
}
if (gitfo_lseek(p->pack_fd, pack_sha1_off, SEEK_SET) == -1)
return GIT_ERROR;
static void pack_window_scan_lru(
struct pack_file *p,
struct pack_file **lru_p,
struct pack_window **lru_w,
struct pack_window **lru_l)
{
struct pack_window *w, *w_l;
for (w_l = NULL, w = p->windows; w; w = w->next) {
if (!w->inuse_cnt) {
if (!*lru_w || w->last_used < (*lru_w)->last_used) {
*lru_p = p;
*lru_w = w;
*lru_l = w_l;
}
}
w_l = w;
}
}
if (gitfo_read(p->pack_fd, pack_id.id, sizeof(pack_id.id)))
return GIT_ERROR;
static int pack_window_close_lru(
struct pack_backend *backend,
struct pack_file *current,
git_file keep_fd)
{
struct pack_file *lru_p = NULL;
struct pack_window *lru_w = NULL, *lru_l = NULL;
size_t i;
if (current)
pack_window_scan_lru(current, &lru_p, &lru_w, &lru_l);
for (i = 0; i < backend->packs.length; ++i)
pack_window_scan_lru(git_vector_get(&backend->packs, i), &lru_p, &lru_w, &lru_l);
if (lru_p) {
backend->mapped -= lru_w->window_map.len;
gitfo_free_map(&lru_w->window_map);
if (lru_l)
lru_l->next = lru_w->next;
else {
lru_p->windows = lru_w->next;
if (!lru_p->windows && lru_p->pack_fd != keep_fd) {
gitfo_close(lru_p->pack_fd);
lru_p->pack_fd = -1;
}
}
git_oid_mkraw(&idx_pack_id, data + idx_pack_sha1_off);
free(lru_w);
backend->open_windows--;
return GIT_SUCCESS;
}
if (git_oid_cmp(&pack_id, &idx_pack_id))
return GIT_ERROR;
}
return GIT_SUCCESS;
static void pack_window_close(struct pack_window **w_cursor)
{
struct pack_window *w = *w_cursor;
if (w) {
w->inuse_cnt--;
*w_cursor = NULL;
}
}
static int open_pack(git_pack *p)
static unsigned char *pack_window_open(
struct pack_backend *backend,
struct pack_file *p,
struct pack_window **w_cursor,
off_t offset,
unsigned int *left)
{
char pb[GIT_PATH_MAX];
struct stat sb;
struct pack_window *win = *w_cursor;
if (p->pack_fd != -1)
return GIT_SUCCESS;
if (p->pack_fd == -1 && packfile_open(p) < GIT_SUCCESS)
return NULL;
if (git__fmt(pb, sizeof(pb), "%s/pack/%s.pack",
p->backend->objects_dir,
p->pack_name) < 0)
return GIT_ERROR;
/* Since packfiles end in a hash of their content and it's
* pointless to ask for an offset into the middle of that
* hash, and the pack_window_contains function above wouldn't match
* don't allow an offset too close to the end of the file.
*/
if (offset > (p->pack_size - 20))
return NULL;
if (pack_openidx(p))
return GIT_ERROR;
if (!win || !pack_window_contains(win, offset)) {
if ((p->pack_fd = gitfo_open(pb, O_RDONLY)) < 0)
goto error_cleanup;
if (win)
win->inuse_cnt--;
if (gitfo_fstat(p->pack_fd, &sb)
|| !S_ISREG(sb.st_mode) || p->pack_size != sb.st_size
|| check_pack_hdr(p) || check_pack_sha1(p))
goto error_cleanup;
for (win = p->windows; win; win = win->next) {
if (pack_window_contains(win, offset))
break;
}
if (!git__is_sizet(p->pack_size) ||
gitfo_map_ro(&p->pack_map, p->pack_fd, 0, (size_t)p->pack_size) < 0)
goto error_cleanup;
if (!win) {
size_t window_align = backend->window_size / 2;
size_t len;
pack_decidx(p);
return GIT_SUCCESS;
win = git__calloc(1, sizeof(*win));
win->offset = (offset / window_align) * window_align;
error_cleanup:
gitfo_close(p->pack_fd);
p->pack_fd = -1;
pack_decidx(p);
return GIT_ERROR;
}
len = (size_t)(p->pack_size - win->offset);
if (len > backend->window_size)
len = backend->window_size;
static void pack_dec(git_pack *p)
{
int need_free;
gitlck_lock(&p->lock);
need_free = !--p->refcnt;
gitlck_unlock(&p->lock);
if (need_free) {
if (p->idx_search) {
gitfo_free_map(&p->idx_map);
gitfo_close(p->idx_fd);
free(p->im_fanout);
free(p->im_off_idx);
free(p->im_off_next);
if (p->pack_fd != -1) {
gitfo_close(p->pack_fd);
gitfo_free_map(&p->pack_map);
backend->mapped += len;
while (backend->mapped_limit < backend->mapped &&
pack_window_close_lru(backend, p, p->pack_fd) == GIT_SUCCESS) {}
if (gitfo_map_ro(&win->window_map, p->pack_fd,
win->offset, len) < GIT_SUCCESS)
return NULL;
backend->mmap_calls++;
backend->open_windows++;
if (backend->mapped > backend->peak_mapped)
backend->peak_mapped = backend->mapped;
if (backend->open_windows > backend->peak_open_windows)
backend->peak_open_windows = backend->open_windows;
win->next = p->windows;
p->windows = win;
}
}
gitlck_free(&p->lock);
free(p);
if (win != *w_cursor) {
win->last_used = backend->used_ctr++;
win->inuse_cnt++;
*w_cursor = win;
}
offset -= win->offset;
assert(git__is_sizet(offset));
if (left)
*left = win->window_map.len - (size_t)offset;
return (unsigned char *)win->window_map.data + offset;
}
static void packlist_dec(pack_backend *backend, git_packlist *pl)
{
int need_free;
assert(backend && pl);
gitlck_lock(&backend->lock);
need_free = !--pl->refcnt;
gitlck_unlock(&backend->lock);
if (need_free) {
size_t j;
for (j = 0; j < pl->n_packs; j++)
pack_dec(pl->packs[j]);
free(pl);
/***********************************************************
*
* PACK INDEX METHODS
*
***********************************************************/
static void pack_index_free(struct pack_file *p)
{
if (p->index_map.data) {
gitfo_free_map(&p->index_map);
p->index_map.data = NULL;
}
}
static git_pack *alloc_pack(const char *pack_name)
static int pack_index_check(const char *path, struct pack_file *p)
{
git_pack *p = git__calloc(1, sizeof(*p));
if (!p)
return NULL;
gitlck_init(&p->lock);
strcpy(p->pack_name, pack_name);
p->refcnt = 1;
p->pack_fd = -1;
return p;
}
struct pack_idx_header *hdr;
uint32_t version, nr, i, *index;
struct scanned_pack {
struct scanned_pack *next;
git_pack *pack;
};
void *idx_map;
size_t idx_size;
static int scan_one_pack(void *state, char *name)
{
struct scanned_pack **ret = state, *r;
char *s = strrchr(name, '/'), *d;
struct stat st;
if (git__prefixcmp(s + 1, "pack-")
|| git__suffixcmp(s, ".pack")
|| strlen(s + 1) != GIT_PACK_NAME_MAX + 4)
return 0;
/* TODO: properly open the file without access time */
git_file fd = gitfo_open(path, O_RDONLY /*| O_NOATIME */);
d = strrchr(s + 1, '.');
strcpy(d + 1, "idx"); /* "pack-abc.pack" -> "pack-abc.idx" */
if (gitfo_exists(name))
return 0;
int error;
if ((r = git__malloc(sizeof(*r))) == NULL)
return GIT_ERROR;
if (fd < 0)
return GIT_EOSERR;
*d = '\0'; /* "pack-abc.pack" -_> "pack-abc" */
if ((r->pack = alloc_pack(s + 1)) == NULL) {
free(r);
return GIT_ERROR;
if (gitfo_fstat(fd, &st) < GIT_SUCCESS) {
gitfo_close(fd);
return GIT_EOSERR;
}
r->next = *ret;
*ret = r;
return 0;
}
if (!git__is_sizet(st.st_size))
return GIT_ENOMEM;
static git_packlist *scan_packs(pack_backend *backend)
{
char pb[GIT_PATH_MAX];
struct scanned_pack *state = NULL, *c;
size_t cnt;
git_packlist *new_list;
idx_size = (size_t)st.st_size;
if (git__fmt(pb, sizeof(pb), "%s/pack", backend->objects_dir) < 0)
return NULL;
gitfo_dirent(pb, sizeof(pb), scan_one_pack, &state);
/* TODO - merge old entries into the new array */
for (cnt = 0, c = state; c; c = c->next)
cnt++;
new_list = git__malloc(sizeof(*new_list)
+ (sizeof(new_list->packs[0]) * cnt));
if (!new_list)
goto fail;
for (cnt = 0, c = state; c; ) {
struct scanned_pack *n = c->next;
c->pack->backend = backend;
new_list->packs[cnt++] = c->pack;
free(c);
c = n;
}
new_list->n_packs = cnt;
new_list->refcnt = 2;
backend->packlist = new_list;
return new_list;
fail:
while (state) {
struct scanned_pack *n = state->next;
pack_dec(state->pack);
free(state);
state = n;
if (idx_size < 4 * 256 + 20 + 20) {
gitfo_close(fd);
return GIT_EOBJCORRUPTED;
}
return NULL;
}
static git_packlist *packlist_get(pack_backend *backend)
{
git_packlist *pl;
error = gitfo_map_ro(&p->index_map, fd, 0, idx_size);
gitfo_close(fd);
gitlck_lock(&backend->lock);
if ((pl = backend->packlist) != NULL)
pl->refcnt++;
else
pl = scan_packs(backend);
gitlck_unlock(&backend->lock);
return pl;
}
if (error < GIT_SUCCESS)
return error;
static int locate_packfile(pack_location *location, pack_backend *backend, const git_oid *id)
{
git_packlist *pl = packlist_get(backend);
size_t j;
hdr = idx_map = p->index_map.data;
if (!pl)
return GIT_ENOTFOUND;
if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
version = ntohl(hdr->idx_version);
for (j = 0; j < pl->n_packs; j++) {
if (version < 2 || version > 2) {
gitfo_free_map(&p->index_map);
return GIT_EOBJCORRUPTED; /* unsupported index version */
}
git_pack *pack = pl->packs[j];
uint32_t pos;
int res;
} else
version = 1;
if (pack_openidx(pack))
continue;
nr = 0;
index = idx_map;
res = pack->idx_search(&pos, pack, id);
pack_decidx(pack);
if (version > 1)
index += 2; /* skip index header */
if (!res) {
packlist_dec(backend, pl);
for (i = 0; i < 256; i++) {
uint32_t n = ntohl(index[i]);
if (n < nr) {
gitfo_free_map(&p->index_map);
return GIT_EOBJCORRUPTED; /* non-monotonic index */
}
nr = n;
}
location->ptr = pack;
location->n = pos;
if (version == 1) {
/*
* Total size:
* - 256 index entries 4 bytes each
* - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
* - 20-byte SHA1 of the packfile
* - 20-byte SHA1 file checksum
*/
if (idx_size != 4*256 + nr * 24 + 20 + 20) {
gitfo_free_map(&p->index_map);
return GIT_EOBJCORRUPTED;
}
} else if (version == 2) {
/*
* Minimum size:
* - 8 bytes of header
* - 256 index entries 4 bytes each
* - 20-byte sha1 entry * nr
* - 4-byte crc entry * nr
* - 4-byte offset entry * nr
* - 20-byte SHA1 of the packfile
* - 20-byte SHA1 file checksum
* And after the 4-byte offset table might be a
* variable sized table containing 8-byte entries
* for offsets larger than 2^31.
*/
unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
unsigned long max_size = min_size;
return GIT_SUCCESS;
if (nr)
max_size += (nr - 1)*8;
if (idx_size < min_size || idx_size > max_size) {
gitfo_free_map(&p->index_map);
return GIT_EOBJCORRUPTED;
}
/* Make sure that off_t is big enough to access the whole pack...
* Is this an issue in libgit2? It shouldn't. */
if (idx_size != min_size && (sizeof(off_t) <= 4)) {
gitfo_free_map(&p->index_map);
return GIT_EOSERR;
}
}
packlist_dec(backend, pl);
return GIT_ENOTFOUND;
p->index_version = version;
p->num_objects = nr;
return GIT_SUCCESS;
}
static int pack_index_open(struct pack_file *p)
{
char *idx_name;
int error;
if (p->index_map.data)
return GIT_SUCCESS;
idx_name = git__strdup(p->pack_name);
strcpy(idx_name + strlen(idx_name) - STRLEN(".pack"), ".idx");
error = pack_index_check(idx_name, p);
free(idx_name);
return error;
}
......@@ -541,574 +663,651 @@ static int locate_packfile(pack_location *location, pack_backend *backend, const
/***********************************************************
*
* PACKFILE INDEX FUNCTIONS
*
* Get index formation for packfile indexes v1 and v2
* PACKFILE METHODS
*
***********************************************************/
static int pack_openidx_map(git_pack *p)
static int packfile_sort__cb(const void *a_, const void *b_)
{
char pb[GIT_PATH_MAX];
git_off_t len;
struct pack_file *a = *((struct pack_file **)a_);
struct pack_file *b = *((struct pack_file **)b_);
int st;
if (git__fmt(pb, sizeof(pb), "%s/pack/%s.idx",
p->backend->objects_dir,
p->pack_name) < 0)
return GIT_ERROR;
/*
* Local packs tend to contain objects specific to our
* variant of the project than remote ones. In addition,
* remote ones could be on a network mounted filesystem.
* Favor local ones for these reasons.
*/
st = a->pack_local - b->pack_local;
if (st)
return -st;
if ((p->idx_fd = gitfo_open(pb, O_RDONLY)) < 0)
return GIT_ERROR;
/*
* Younger packs tend to contain more recent objects,
* and more recent objects tend to get accessed more
* often.
*/
if (a->mtime < b->mtime)
return 1;
else if (a->mtime == b->mtime)
return 0;
if ((len = gitfo_size(p->idx_fd)) < 0
|| !git__is_sizet(len)
|| gitfo_map_ro(&p->idx_map, p->idx_fd, 0, (size_t)len)) {
gitfo_close(p->idx_fd);
return GIT_ERROR;
}
return -1;
}
return GIT_SUCCESS;
static struct pack_file *packfile_alloc(int extra)
{
struct pack_file *p = git__malloc(sizeof(*p) + extra);
memset(p, 0, sizeof(*p));
p->pack_fd = -1;
return p;
}
typedef struct {
git_off_t offset;
uint32_t n;
} offset_idx_info;
static int cmp_offset_idx_info(const void *lhs, const void *rhs)
static void packfile_free(struct pack_backend *backend, struct pack_file *p)
{
const offset_idx_info *a = lhs;
const offset_idx_info *b = rhs;
return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
assert(p);
/* clear_delta_base_cache(); */
pack_window_free_all(backend, p);
if (p->pack_fd != -1)
gitfo_close(p->pack_fd);
pack_index_free(p);
free(p->bad_object_sha1);
free(p);
}
static int make_offset_index(git_pack *p, offset_idx_info *data)
static int packfile_open(struct pack_file *p)
{
git_off_t min_off = 3 * 4, max_off = p->pack_size - GIT_OID_RAWSZ;
uint32_t *idx, *next;
uint32_t j;
struct stat st;
struct pack_header hdr;
git_oid sha1;
unsigned char *idx_sha1;
if (!p->index_map.data && pack_index_open(p) < GIT_SUCCESS)
return GIT_ENOTFOUND;
qsort(data, p->obj_cnt, sizeof(*data), cmp_offset_idx_info);
/* TODO: open with noatime */
p->pack_fd = gitfo_open(p->pack_name, O_RDONLY);
if (p->pack_fd < 0 || gitfo_fstat(p->pack_fd, &st) < GIT_SUCCESS)
return GIT_EOSERR;
if (data[0].offset < min_off || data[p->obj_cnt].offset > max_off)
return GIT_ERROR;
/* If we created the struct before we had the pack we lack size. */
if (!p->pack_size) {
if (!S_ISREG(st.st_mode))
goto cleanup;
p->pack_size = (off_t)st.st_size;
} else if (p->pack_size != st.st_size)
goto cleanup;
if ((idx = git__malloc(sizeof(*idx) * (p->obj_cnt+1))) == NULL)
return GIT_ERROR;
if ((next = git__malloc(sizeof(*next) * p->obj_cnt)) == NULL) {
free(idx);
return GIT_ERROR;
#if 0
/* We leave these file descriptors open with sliding mmap;
* there is no point keeping them open across exec(), though.
*/
fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
if (fd_flag < 0)
return error("cannot determine file descriptor flags");
fd_flag |= FD_CLOEXEC;
if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
return GIT_EOSERR;
#endif
/* Verify we recognize this pack file format. */
if (gitfo_read(p->pack_fd, &hdr, sizeof(hdr)) < GIT_SUCCESS)
goto cleanup;
if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
goto cleanup;
if (!pack_version_ok(hdr.hdr_version))
goto cleanup;
/* Verify the pack matches its index. */
if (p->num_objects != ntohl(hdr.hdr_entries))
goto cleanup;
if (gitfo_lseek(p->pack_fd, p->pack_size - GIT_OID_RAWSZ, SEEK_SET) == -1)
goto cleanup;
if (gitfo_read(p->pack_fd, sha1.id, GIT_OID_RAWSZ) < GIT_SUCCESS)
goto cleanup;
idx_sha1 = ((unsigned char *)p->index_map.data) + p->index_map.len - 40;
if (git_oid_cmp(&sha1, (git_oid *)idx_sha1) != 0)
goto cleanup;
return GIT_SUCCESS;
cleanup:
gitfo_close(p->pack_fd);
p->pack_fd = -1;
return GIT_EPACKCORRUPTED;
}
static int packfile_check(struct pack_file **pack_out, const char *path, int local)
{
struct stat st;
struct pack_file *p;
size_t path_len;
*pack_out = NULL;
path_len = strlen(path);
p = packfile_alloc(path_len + 2);
/*
* Make sure a corresponding .pack file exists and that
* the index looks sane.
*/
path_len -= STRLEN(".idx");
if (path_len < 1) {
free(p);
return GIT_ENOTFOUND;
}
for (j = 0; j < p->obj_cnt+1; j++)
idx[j] = data[j].n;
memcpy(p->pack_name, path, path_len);
for (j = 0; j < p->obj_cnt; j++) {
assert(idx[j] < p->obj_cnt);
assert(idx[j+1] < p->obj_cnt+1);
strcpy(p->pack_name + path_len, ".keep");
if (gitfo_exists(p->pack_name) == GIT_SUCCESS)
p->pack_keep = 1;
next[idx[j]] = idx[j+1];
strcpy(p->pack_name + path_len, ".pack");
if (gitfo_stat(p->pack_name, &st) < GIT_SUCCESS || !S_ISREG(st.st_mode)) {
free(p);
return GIT_ENOTFOUND;
}
p->im_off_idx = idx;
p->im_off_next = next;
/* ok, it looks sane as far as we can check without
* actually mapping the pack file.
*/
p->pack_size = (off_t)st.st_size;
p->pack_local = local;
p->mtime = st.st_mtime;
/* see if we can parse the sha1 oid in the packfile name */
if (path_len < 40 ||
git_oid_mkstr(&p->sha1, path + path_len - GIT_OID_HEXSZ) < GIT_SUCCESS)
memset(&p->sha1, 0x0, GIT_OID_RAWSZ);
*pack_out = p;
return GIT_SUCCESS;
}
static int idxv1_search(uint32_t *out, git_pack *p, const git_oid *id)
static int packfile_load__cb(void *_data, char *path)
{
unsigned char *data = p->im_oid;
uint32_t lo = id->id[0] ? p->im_fanout[id->id[0] - 1] : 0;
uint32_t hi = p->im_fanout[id->id[0]];
struct pack__dirent *data = (struct pack__dirent *)_data;
struct pack_file *pack;
int error;
if (git__suffixcmp(path, ".idx") != 0)
return GIT_SUCCESS; /* not an index */
/* FIXME: git.git checks for duplicate packs.
* But that makes no fucking sense. Our dirent is not
* going to generate dupicate entries */
error = packfile_check(&pack, path, data->is_pack_local);
if (error < GIT_SUCCESS)
return error;
if (git_vector_insert(&data->backend->packs, pack) < GIT_SUCCESS) {
free(pack);
return GIT_ENOMEM;
}
do {
uint32_t mid = (lo + hi) >> 1;
uint32_t pos = 24 * mid;
int cmp = memcmp(id->id, data + pos + 4, 20);
if (cmp < 0)
hi = mid;
else if (!cmp) {
*out = mid;
return GIT_SUCCESS;
} else
lo = mid + 1;
} while (lo < hi);
return GIT_ENOTFOUND;
}
static int idxv1_search_offset(uint32_t *out, git_pack *p, git_off_t offset)
static int packfile_load_all(struct pack_backend *backend, const char *odb_path, int local)
{
if (offset > 0 && offset < (p->pack_size - GIT_OID_RAWSZ)) {
uint32_t lo = 0, hi = p->obj_cnt+1;
unsigned char *data = p->im_oid;
uint32_t *idx = p->im_off_idx;
do {
uint32_t mid = (lo + hi) >> 1;
uint32_t n = idx[mid];
uint32_t pos = n * (GIT_OID_RAWSZ + 4);
git_off_t here = decode32(data + pos);
if (offset < here)
hi = mid;
else if (offset == here) {
*out = n;
int error;
char path[GIT_PATH_MAX];
struct pack__dirent data;
data.backend = backend;
data.is_pack_local = local;
git__joinpath(path, odb_path, "pack");
if (gitfo_isdir(path) < GIT_SUCCESS)
return GIT_SUCCESS;
error = gitfo_dirent(path, GIT_PATH_MAX, packfile_load__cb, (void *)&data);
if (error < GIT_SUCCESS)
return error;
git_vector_sort(&backend->packs);
backend->last_found = git_vector_get(&backend->packs, 0);
return GIT_SUCCESS;
} else
lo = mid + 1;
} while (lo < hi);
}
return GIT_ENOTFOUND;
}
static int idxv1_get(index_entry *e, git_pack *p, uint32_t n)
/***********************************************************
*
* PACKFILE ENTRY SEARCH INTERNALS
*
***********************************************************/
static off_t nth_packed_object_offset(const struct pack_file *p, uint32_t n)
{
unsigned char *data = p->im_oid;
uint32_t *next = p->im_off_next;
if (n < p->obj_cnt) {
uint32_t pos = n * (GIT_OID_RAWSZ + 4);
git_off_t next_off = p->pack_size - GIT_OID_RAWSZ;
e->n = n;
e->oid = data + pos + 4;
e->offset = decode32(data + pos);
if (next[n] < p->obj_cnt) {
pos = next[n] * (GIT_OID_RAWSZ + 4);
next_off = decode32(data + pos);
const unsigned char *index = p->index_map.data;
index += 4 * 256;
if (p->index_version == 1) {
return ntohl(*((uint32_t *)(index + 24 * n)));
} else {
uint32_t off;
index += 8 + p->num_objects * (20 + 4);
off = ntohl(*((uint32_t *)(index + 4 * n)));
if (!(off & 0x80000000))
return off;
index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
ntohl(*((uint32_t *)(index + 4)));
}
e->size = next_off - e->offset;
return GIT_SUCCESS;
}
return GIT_ENOTFOUND;
}
static int pack_openidx_v1(git_pack *p)
static int pack_entry_find_offset(
off_t *offset_out,
struct pack_file *p,
const git_oid *oid)
{
uint32_t *src_fanout = p->idx_map.data;
uint32_t *im_fanout;
offset_idx_info *info;
size_t expsz;
uint32_t j;
const uint32_t *level1_ofs = p->index_map.data;
const unsigned char *index = p->index_map.data;
unsigned hi, lo, stride;
*offset_out = 0;
if ((im_fanout = git__malloc(sizeof(*im_fanout) * 256)) == NULL)
return GIT_ERROR;
if (index == NULL) {
int error;
im_fanout[0] = decode32(&src_fanout[0]);
for (j = 1; j < 256; j++) {
im_fanout[j] = decode32(&src_fanout[j]);
if (im_fanout[j] < im_fanout[j - 1]) {
free(im_fanout);
return GIT_ERROR;
}
if ((error = pack_index_open(p)) < GIT_SUCCESS)
return error;
assert(p->index_map.data);
index = p->index_map.data;
level1_ofs = p->index_map.data;
}
p->obj_cnt = im_fanout[255];
expsz = 4 * 256 + 24 * p->obj_cnt + 2 * 20;
if (expsz != p->idx_map.len) {
free(im_fanout);
return GIT_ERROR;
if (p->index_version > 1) {
level1_ofs += 2;
index += 8;
}
p->idx_search = idxv1_search;
p->idx_search_offset = idxv1_search_offset;
p->idx_get = idxv1_get;
p->im_fanout = im_fanout;
p->im_oid = (unsigned char *)(src_fanout + 256);
index += 4 * 256;
hi = ntohl(level1_ofs[(int)oid->id[0]]);
lo = ((oid->id[0] == 0x0) ? 0 : ntohl(level1_ofs[(int)oid->id[0] - 1]));
if ((info = git__malloc(sizeof(*info) * (p->obj_cnt+1))) == NULL) {
free(im_fanout);
return GIT_ERROR;
if (p->index_version > 1) {
stride = 20;
} else {
stride = 24;
index += 4;
}
for (j = 0; j < p->obj_cnt; j++) {
uint32_t pos = j * (GIT_OID_RAWSZ + 4);
info[j].offset = decode32(p->im_oid + pos);
info[j].n = j;
}
info[p->obj_cnt].offset = p->pack_size - GIT_OID_RAWSZ;
info[p->obj_cnt].n = p->obj_cnt;
#ifdef INDEX_DEBUG_LOOKUP
printf("%02x%02x%02x... lo %u hi %u nr %d\n",
oid->id[0], oid->id[1], oid->id[2], lo, hi, p->num_objects);
#endif
if (make_offset_index(p, info)) {
free(im_fanout);
free(info);
return GIT_ERROR;
}
free(info);
#ifdef GIT2_INDEX_LOOKUP /* TODO: use the advanced lookup method from git.git */
int pos = sha1_entry_pos(index, stride, 0, lo, hi, p->num_objects, oid);
if (pos < 0)
return GIT_ENOTFOUND;
*offset_out = nth_packed_object_offset(p, pos);
return GIT_SUCCESS;
}
static int idxv2_search(uint32_t *out, git_pack *p, const git_oid *id)
{
unsigned char *data = p->im_oid;
uint32_t lo = id->id[0] ? p->im_fanout[id->id[0] - 1] : 0;
uint32_t hi = p->im_fanout[id->id[0]];
#else /* use an old and boring binary search */
do {
uint32_t mid = (lo + hi) >> 1;
uint32_t pos = 20 * mid;
int cmp = memcmp(id->id, data + pos, 20);
if (cmp < 0)
hi = mid;
else if (!cmp) {
*out = mid;
return GIT_SUCCESS;
} else
lo = mid + 1;
} while (lo < hi);
return GIT_ENOTFOUND;
}
unsigned mi = (lo + hi) / 2;
int cmp = memcmp(index + mi * stride, oid->id, GIT_OID_RAWSZ);
static int idxv2_search_offset(uint32_t *out, git_pack *p, git_off_t offset)
{
if (offset > 0 && offset < (p->pack_size - GIT_OID_RAWSZ)) {
uint32_t lo = 0, hi = p->obj_cnt+1;
uint32_t *idx = p->im_off_idx;
do {
uint32_t mid = (lo + hi) >> 1;
uint32_t n = idx[mid];
uint32_t o32 = decode32(p->im_offset32 + n);
git_off_t here = o32;
if (o32 & 0x80000000) {
uint32_t o64_idx = (o32 & ~0x80000000);
here = decode64(p->im_offset64 + 2*o64_idx);
if (!cmp) {
*offset_out = nth_packed_object_offset(p, mi);
return GIT_SUCCESS;
}
if (offset < here)
hi = mid;
else if (offset == here) {
*out = n;
return GIT_SUCCESS;
} else
lo = mid + 1;
if (cmp > 0)
hi = mi;
else
lo = mi+1;
} while (lo < hi);
}
return GIT_ENOTFOUND;
}
static int idxv2_get(index_entry *e, git_pack *p, uint32_t n)
{
unsigned char *data = p->im_oid;
uint32_t *next = p->im_off_next;
if (n < p->obj_cnt) {
uint32_t o32 = decode32(p->im_offset32 + n);
git_off_t next_off = p->pack_size - GIT_OID_RAWSZ;
e->n = n;
e->oid = data + n * GIT_OID_RAWSZ;
e->offset = o32;
if (o32 & 0x80000000) {
uint32_t o64_idx = (o32 & ~0x80000000);
e->offset = decode64(p->im_offset64 + 2*o64_idx);
}
if (next[n] < p->obj_cnt) {
o32 = decode32(p->im_offset32 + next[n]);
next_off = o32;
if (o32 & 0x80000000) {
uint32_t o64_idx = (o32 & ~0x80000000);
next_off = decode64(p->im_offset64 + 2*o64_idx);
}
}
e->size = next_off - e->offset;
return GIT_SUCCESS;
}
return GIT_ENOTFOUND;
#endif
}
static int pack_openidx_v2(git_pack *p)
static int pack_entry_find1(
struct pack_entry *e,
struct pack_file *p,
const git_oid *oid)
{
unsigned char *data = p->idx_map.data;
uint32_t *src_fanout = (uint32_t *)(data + 8);
uint32_t *im_fanout;
offset_idx_info *info;
size_t sz, o64_sz, o64_len;
uint32_t j;
if ((im_fanout = git__malloc(sizeof(*im_fanout) * 256)) == NULL)
return GIT_ERROR;
off_t offset;
im_fanout[0] = decode32(&src_fanout[0]);
for (j = 1; j < 256; j++) {
im_fanout[j] = decode32(&src_fanout[j]);
if (im_fanout[j] < im_fanout[j - 1]) {
free(im_fanout);
return GIT_ERROR;
}
}
p->obj_cnt = im_fanout[255];
assert(p);
/* minimum size of .idx file (with empty 64-bit offsets table): */
sz = 4 + 4 + 256 * 4 + p->obj_cnt * (20 + 4 + 4) + 2 * 20;
if (p->idx_map.len < sz) {
free(im_fanout);
if (p->num_bad_objects) {
unsigned i;
for (i = 0; i < p->num_bad_objects; i++)
if (git_oid_cmp(oid, &p->bad_object_sha1[i]) == 0)
return GIT_ERROR;
}
p->idx_search = idxv2_search;
p->idx_search_offset = idxv2_search_offset;
p->idx_get = idxv2_get;
p->im_fanout = im_fanout;
p->im_oid = (unsigned char *)(src_fanout + 256);
p->im_crc = (uint32_t *)(p->im_oid + 20 * p->obj_cnt);
p->im_offset32 = p->im_crc + p->obj_cnt;
p->im_offset64 = p->im_offset32 + p->obj_cnt;
if ((info = git__malloc(sizeof(*info) * (p->obj_cnt+1))) == NULL) {
free(im_fanout);
return GIT_ERROR;
}
if (pack_entry_find_offset(&offset, p, oid) < GIT_SUCCESS)
return GIT_ENOTFOUND;
/* check 64-bit offset table index values are within bounds */
o64_sz = p->idx_map.len - sz;
o64_len = o64_sz / 8;
for (j = 0; j < p->obj_cnt; j++) {
uint32_t o32 = decode32(p->im_offset32 + j);
git_off_t offset = o32;
if (o32 & 0x80000000) {
uint32_t o64_idx = (o32 & ~0x80000000);
if (o64_idx >= o64_len) {
free(im_fanout);
free(info);
return GIT_ERROR;
}
offset = decode64(p->im_offset64 + 2*o64_idx);
}
info[j].offset = offset;
info[j].n = j;
}
info[p->obj_cnt].offset = p->pack_size - GIT_OID_RAWSZ;
info[p->obj_cnt].n = p->obj_cnt;
/* we found an entry in the index;
* make sure the packfile backing the index
* still exists on disk */
if (p->pack_fd == -1 && packfile_open(p) < GIT_SUCCESS)
return GIT_EOSERR;
if (make_offset_index(p, info)) {
free(im_fanout);
free(info);
return GIT_ERROR;
}
free(info);
e->offset = offset;
e->p = p;
git_oid_cpy(&e->sha1, oid);
return GIT_SUCCESS;
}
static int pack_entry_find(struct pack_entry *e, struct pack_backend *backend, const git_oid *oid)
{
size_t i;
if (backend->last_found &&
pack_entry_find1(e, backend->last_found, oid) == GIT_SUCCESS)
return GIT_SUCCESS;
for (i = 0; i < backend->packs.length; ++i) {
struct pack_file *p;
p = git_vector_get(&backend->packs, i);
if (p == backend->last_found)
continue;
if (pack_entry_find1(e, p, oid) == GIT_SUCCESS) {
backend->last_found = p;
return GIT_SUCCESS;
}
}
return GIT_ENOTFOUND;
}
/***********************************************************
*
* PACKFILE READING FUNCTIONS
*
* Read the contents of a packfile
*
***********************************************************/
static int unpack_object(git_rawobj *out, git_pack *p, index_entry *e);
static int unpack_object_delta(git_rawobj *out, git_pack *p,
index_entry *base_entry,
uint8_t *delta_buffer,
size_t delta_deflated_size,
size_t delta_inflated_size)
{
int res = 0;
uint8_t *delta = NULL;
git_rawobj base_obj;
base_obj.data = NULL;
base_obj.type = GIT_OBJ_BAD;
base_obj.len = 0;
if ((res = unpack_object(&base_obj, p, base_entry)) < 0)
goto cleanup;
delta = git__malloc(delta_inflated_size + 1);
if ((res = git_odb__inflate_buffer(delta_buffer, delta_deflated_size,
delta, delta_inflated_size)) < 0)
goto cleanup;
res = git__delta_apply(out, base_obj.data, base_obj.len, delta, delta_inflated_size);
out->type = base_obj.type;
cleanup:
free(delta);
git_rawobj_close(&base_obj);
return res;
}
/***********************************************************
*
* PACKFILE ENTRY UNPACK INTERNALS
*
***********************************************************/
static int unpack_object(git_rawobj *out, git_pack *p, index_entry *e)
static unsigned long packfile_unpack_header1(
size_t *sizep,
git_otype *type,
const unsigned char *buf,
unsigned long len)
{
git_otype object_type;
size_t inflated_size, deflated_size, shift;
uint8_t *buffer, byte;
assert(out && p && e && git__is_sizet(e->size));
if (open_pack(p))
return GIT_ERROR;
buffer = (uint8_t *)p->pack_map.data + e->offset;
deflated_size = (size_t)e->size;
unsigned shift;
unsigned long size, c;
unsigned long used = 0;
if (deflated_size == 0)
deflated_size = (size_t)(p->pack_size - e->offset);
byte = *buffer++ & 0xFF;
deflated_size--;
object_type = (byte >> 4) & 0x7;
inflated_size = byte & 0xF;
c = buf[used++];
*type = (c >> 4) & 7;
size = c & 15;
shift = 4;
while (c & 0x80) {
if (len <= used || bitsizeof(long) <= shift)
return 0;
while (byte & 0x80) {
byte = *buffer++ & 0xFF;
deflated_size--;
inflated_size += (byte & 0x7F) << shift;
c = buf[used++];
size += (c & 0x7f) << shift;
shift += 7;
}
switch (object_type) {
case GIT_OBJ_COMMIT:
case GIT_OBJ_TREE:
case GIT_OBJ_BLOB:
case GIT_OBJ_TAG: {
/* Handle a normal zlib stream */
out->len = inflated_size;
out->type = object_type;
out->data = git__malloc(inflated_size + 1);
if (git_odb__inflate_buffer(buffer, deflated_size, out->data, out->len) < 0) {
free(out->data);
out->data = NULL;
return GIT_ERROR;
}
*sizep = (size_t)size;
return used;
}
return GIT_SUCCESS;
}
static int packfile_unpack_header(
size_t *size_p,
git_otype *type_p,
struct pack_backend *backend,
struct pack_file *p,
struct pack_window **w_curs,
off_t *curpos)
{
unsigned char *base;
unsigned int left;
unsigned long used;
/* pack_window_open() assures us we have [base, base + 20) available
* as a range that we can look at at. (Its actually the hash
* size that is assured.) With our object header encoding
* the maximum deflated object size is 2^137, which is just
* insane, so we know won't exceed what we have been given.
*/
base = pack_window_open(backend, p, w_curs, *curpos, &left);
if (base == NULL)
return GIT_ENOMEM;
case GIT_OBJ_OFS_DELTA: {
used = packfile_unpack_header1(size_p, type_p, base, left);
git_off_t delta_offset;
index_entry entry;
if (used == 0)
return GIT_EOBJCORRUPTED;
byte = *buffer++ & 0xFF;
delta_offset = byte & 0x7F;
*curpos += used;
return GIT_SUCCESS;
}
while (byte & 0x80) {
delta_offset += 1;
byte = *buffer++ & 0xFF;
delta_offset <<= 7;
delta_offset += (byte & 0x7F);
}
static int packfile_unpack_compressed(
git_rawobj *obj,
struct pack_backend *backend,
struct pack_file *p,
struct pack_window **w_curs,
off_t curpos,
size_t size,
git_otype type)
{
int st;
z_stream stream;
unsigned char *buffer, *in;
entry.n = 0;
entry.oid = NULL;
entry.offset = e->offset - delta_offset;
entry.size = 0;
buffer = git__malloc(size);
if (unpack_object_delta(out, p, &entry,
buffer, deflated_size, inflated_size) < 0)
return GIT_ERROR;
memset(&stream, 0, sizeof(stream));
stream.next_out = buffer;
stream.avail_out = size + 1;
return GIT_SUCCESS;
st = inflateInit(&stream);
if (st != Z_OK) {
free(buffer);
return GIT_EZLIB;
}
case GIT_OBJ_REF_DELTA: {
do {
in = pack_window_open(backend, p, w_curs, curpos, &stream.avail_in);
stream.next_in = in;
st = inflate(&stream, Z_FINISH);
git_oid base_id;
uint32_t n;
index_entry entry;
int res = GIT_ERROR;
if (!stream.avail_out)
break; /* the payload is larger than it should be */
git_oid_mkraw(&base_id, buffer);
curpos += stream.next_in - in;
} while (st == Z_OK || st == Z_BUF_ERROR);
if (!p->idx_search(&n, p, &base_id) &&
!p->idx_get(&entry, p, n)) {
inflateEnd(&stream);
res = unpack_object_delta(out, p, &entry,
buffer + GIT_OID_RAWSZ, deflated_size, inflated_size);
if ((st != Z_STREAM_END) || stream.total_out != size) {
free(buffer);
return GIT_EZLIB;
}
return res;
}
obj->type = type;
obj->len = size;
obj->data = buffer;
return GIT_SUCCESS;
}
default:
return GIT_EOBJCORRUPTED;
static off_t get_delta_base(
struct pack_backend *backend,
struct pack_file *p,
struct pack_window **w_curs,
off_t *curpos,
git_otype type,
off_t delta_obj_offset)
{
unsigned char *base_info = pack_window_open(backend, p, w_curs, *curpos, NULL);
off_t base_offset;
/* pack_window_open() assured us we have [base_info, base_info + 20)
* as a range that we can look at without walking off the
* end of the mapped window. Its actually the hash size
* that is assured. An OFS_DELTA longer than the hash size
* is stupid, as then a REF_DELTA would be smaller to store.
*/
if (type == GIT_OBJ_OFS_DELTA) {
unsigned used = 0;
unsigned char c = base_info[used++];
base_offset = c & 127;
while (c & 128) {
base_offset += 1;
if (!base_offset || MSB(base_offset, 7))
return 0; /* overflow */
c = base_info[used++];
base_offset = (base_offset << 7) + (c & 127);
}
base_offset = delta_obj_offset - base_offset;
if (base_offset <= 0 || base_offset >= delta_obj_offset)
return 0; /* out of bound */
*curpos += used;
} else if (type == GIT_OBJ_REF_DELTA) {
/* The base entry _must_ be in the same pack */
if (pack_entry_find_offset(&base_offset, p, (git_oid *)base_info) < GIT_SUCCESS)
return GIT_EPACKCORRUPTED;
*curpos += 20;
} else
return 0;
return base_offset;
}
static int read_packed(git_rawobj *out, const pack_location *loc)
static int packfile_unpack_delta(
git_rawobj *obj,
struct pack_backend *backend,
struct pack_file *p,
struct pack_window **w_curs,
off_t curpos,
size_t delta_size,
git_otype delta_type,
off_t obj_offset)
{
index_entry e;
int res;
off_t base_offset;
git_rawobj base, delta;
int error;
assert(out && loc);
base_offset = get_delta_base(backend, p, w_curs, &curpos, delta_type, obj_offset);
if (base_offset == 0)
return GIT_EOBJCORRUPTED;
if (pack_openidx(loc->ptr) < 0)
return GIT_EPACKCORRUPTED;
pack_window_close(w_curs);
error = packfile_unpack(&base, backend, p, base_offset);
res = loc->ptr->idx_get(&e, loc->ptr, loc->n);
/* TODO: git.git tries to load the base from other packfiles
* or loose objects */
if (error < GIT_SUCCESS)
return error;
if (!res)
res = unpack_object(out, loc->ptr, &e);
error = packfile_unpack_compressed(&delta, backend, p, w_curs, curpos, delta_size, delta_type);
if (error < GIT_SUCCESS) {
git_rawobj_close(&base);
return error;
}
obj->type = base.type;
error = git__delta_apply(obj,
base.data, base.len,
delta.data, delta.len);
pack_decidx(loc->ptr);
git_rawobj_close(&base);
git_rawobj_close(&delta);
return res;
/* TODO: we might want to cache this shit. eventually */
//add_delta_base_cache(p, base_offset, base, base_size, *type);
return error;
}
static int read_header_packed(git_rawobj *out, const pack_location *loc)
static int packfile_unpack(
git_rawobj *obj,
struct pack_backend *backend,
struct pack_file *p,
off_t obj_offset)
{
git_pack *pack;
index_entry e;
int error = GIT_SUCCESS, shift;
uint8_t *buffer, byte;
struct pack_window *w_curs = NULL;
off_t curpos = obj_offset;
int error;
assert(out && loc);
size_t size;
git_otype type;
pack = loc->ptr;
if (pack_openidx(pack))
return GIT_EPACKCORRUPTED;
if (pack->idx_get(&e, pack, loc->n) < 0 ||
open_pack(pack) < 0) {
error = GIT_ENOTFOUND;
goto cleanup;
}
/*
* TODO: optionally check the CRC on the packfile
*/
buffer = (uint8_t *)pack->pack_map.data + e.offset;
obj->data = NULL;
obj->len = 0;
obj->type = GIT_OBJ_BAD;
byte = *buffer++ & 0xFF;
out->type = (byte >> 4) & 0x7;
out->len = byte & 0xF;
shift = 4;
error = packfile_unpack_header(&size, &type, backend, p, &w_curs, &curpos);
if (error < GIT_SUCCESS)
return error;
while (byte & 0x80) {
byte = *buffer++ & 0xFF;
out->len += (byte & 0x7F) << shift;
shift += 7;
}
switch (type) {
case GIT_OBJ_OFS_DELTA:
case GIT_OBJ_REF_DELTA:
error = packfile_unpack_delta(
obj, backend, p, &w_curs, curpos,
size, type, obj_offset);
break;
/*
* FIXME: if the object is not packed as a whole,
* we need to do a full load and apply the deltas before
* being able to read the header.
*
* I don't think there are any workarounds for this.'
*/
case GIT_OBJ_COMMIT:
case GIT_OBJ_TREE:
case GIT_OBJ_BLOB:
case GIT_OBJ_TAG:
error = packfile_unpack_compressed(
obj, backend, p, &w_curs, curpos,
size, type);
break;
if (out->type == GIT_OBJ_OFS_DELTA || out->type == GIT_OBJ_REF_DELTA) {
error = unpack_object(out, pack, &e);
git_rawobj_close(out);
default:
error = GIT_EOBJCORRUPTED;
break;
}
cleanup:
pack_decidx(loc->ptr);
pack_window_close(&w_curs);
return error;
}
......@@ -1116,8 +1315,6 @@ cleanup:
/***********************************************************
*
* PACKED BACKEND PUBLIC API
......@@ -1126,79 +1323,80 @@ cleanup:
*
***********************************************************/
/*
int pack_backend__read_header(git_rawobj *obj, git_odb_backend *backend, const git_oid *oid)
{
pack_location location;
assert(obj && backend && oid);
if (locate_packfile(&location, (pack_backend *)backend, oid) < 0)
if (locate_packfile(&location, (struct pack_backend *)backend, oid) < 0)
return GIT_ENOTFOUND;
return read_header_packed(obj, &location);
}
*/
int pack_backend__read(git_rawobj *obj, git_odb_backend *backend, const git_oid *oid)
{
pack_location location;
struct pack_entry e;
int error;
assert(obj && backend && oid);
if (locate_packfile(&location, (pack_backend *)backend, oid) < 0)
return GIT_ENOTFOUND;
if ((error = pack_entry_find(&e, (struct pack_backend *)backend, oid)) < GIT_SUCCESS)
return error;
return read_packed(obj, &location);
return packfile_unpack(obj, (struct pack_backend *)backend, e.p, e.offset);
}
int pack_backend__exists(git_odb_backend *backend, const git_oid *oid)
{
pack_location location;
assert(backend && oid);
return locate_packfile(&location, (pack_backend *)backend, oid) == GIT_SUCCESS;
struct pack_entry e;
return pack_entry_find(&e, (struct pack_backend *)backend, oid) == GIT_SUCCESS;
}
void pack_backend__free(git_odb_backend *_backend)
{
pack_backend *backend;
git_packlist *pl;
struct pack_backend *backend;
size_t i;
assert(_backend);
backend = (pack_backend *)_backend;
gitlck_lock(&backend->lock);
pl = backend->packlist;
backend->packlist = NULL;
backend = (struct pack_backend *)_backend;
gitlck_unlock(&backend->lock);
if (pl)
packlist_dec(backend, pl);
gitlck_free(&backend->lock);
for (i = 0; i < backend->packs.length; ++i) {
struct pack_file *p = git_vector_get(&backend->packs, i);
packfile_free(backend, p);
}
free(backend->objects_dir);
git_vector_free(&backend->packs);
free(backend);
}
int git_odb_backend_pack(git_odb_backend **backend_out, const char *objects_dir)
{
pack_backend *backend;
int error;
struct pack_backend *backend;
backend = git__calloc(1, sizeof(pack_backend));
backend = git__calloc(1, sizeof(struct pack_backend));
if (backend == NULL)
return GIT_ENOMEM;
backend->objects_dir = git__strdup(objects_dir);
if (backend->objects_dir == NULL) {
if (git_vector_init(&backend->packs, 8, packfile_sort__cb) < GIT_SUCCESS) {
free(backend);
return GIT_ENOMEM;
}
gitlck_init(&backend->lock);
backend->window_size = DEFAULT_WINDOW_SIZE;
backend->mapped_limit = DEFAULT_MAPPED_LIMIT;
error = packfile_load_all(backend, objects_dir, 1);
if (error < GIT_SUCCESS) {
pack_backend__free((git_odb_backend *)backend);
return error;
}
backend->parent.read = &pack_backend__read;
backend->parent.read_header = &pack_backend__read_header;
backend->parent.read_header = NULL;
backend->parent.write = NULL;
backend->parent.exists = &pack_backend__exists;
backend->parent.free = &pack_backend__free;
......
src/util.h
......@@ -2,6 +2,8 @@
#define INCLUDE_util_h__
#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
#define bitsizeof(x) (CHAR_BIT * sizeof(x))
#define MSB(x, bits) ((x) & (~0ULL << (bitsizeof(x) - (bits))))
/*
* Don't wrap malloc/calloc.
......
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