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tag: v1.4.3.2
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/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*
* This handles basic git sha1 object files - packing, unpacking,
* creation etc.
*/
#include "cache.h"
#include "delta.h"
#include "pack.h"
#include "blob.h"
#include "commit.h"
#include "tag.h"
#include "tree.h"

#ifndef O_NOATIME
#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
#define O_NOATIME 01000000
#else
#define O_NOATIME 0
#endif
#endif

const unsigned char null_sha1[20];

static unsigned int sha1_file_open_flag = O_NOATIME;

signed char hexval_table[256] = {
-1, -1, -1, -1, -1, -1, -1, -1, /* 00-07 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 08-0f */
-1, -1, -1, -1, -1, -1, -1, -1, /* 10-17 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 18-1f */
-1, -1, -1, -1, -1, -1, -1, -1, /* 20-27 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 28-2f */
0, 1, 2, 3, 4, 5, 6, 7, /* 30-37 */
8, 9, -1, -1, -1, -1, -1, -1, /* 38-3f */
-1, 10, 11, 12, 13, 14, 15, -1, /* 40-47 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 48-4f */
-1, -1, -1, -1, -1, -1, -1, -1, /* 50-57 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 58-5f */
-1, 10, 11, 12, 13, 14, 15, -1, /* 60-67 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 68-67 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 70-77 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 78-7f */
-1, -1, -1, -1, -1, -1, -1, -1, /* 80-87 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 88-8f */
-1, -1, -1, -1, -1, -1, -1, -1, /* 90-97 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 98-9f */
-1, -1, -1, -1, -1, -1, -1, -1, /* a0-a7 */
-1, -1, -1, -1, -1, -1, -1, -1, /* a8-af */
-1, -1, -1, -1, -1, -1, -1, -1, /* b0-b7 */
-1, -1, -1, -1, -1, -1, -1, -1, /* b8-bf */
-1, -1, -1, -1, -1, -1, -1, -1, /* c0-c7 */
-1, -1, -1, -1, -1, -1, -1, -1, /* c8-cf */
-1, -1, -1, -1, -1, -1, -1, -1, /* d0-d7 */
-1, -1, -1, -1, -1, -1, -1, -1, /* d8-df */
-1, -1, -1, -1, -1, -1, -1, -1, /* e0-e7 */
-1, -1, -1, -1, -1, -1, -1, -1, /* e8-ef */
-1, -1, -1, -1, -1, -1, -1, -1, /* f0-f7 */
-1, -1, -1, -1, -1, -1, -1, -1, /* f8-ff */
};

int get_sha1_hex(const char *hex, unsigned char *sha1)
{
int i;
for (i = 0; i < 20; i++) {
unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
if (val & ~0xff)
return -1;
*sha1++ = val;
hex += 2;
}
return 0;
}

int safe_create_leading_directories(char *path)
{
char *pos = path;
struct stat st;

if (*pos == '/')
pos++;

while (pos) {
pos = strchr(pos, '/');
if (!pos)
break;
*pos = 0;
if (!stat(path, &st)) {
/* path exists */
if (!S_ISDIR(st.st_mode)) {
*pos = '/';
return -3;
}
}
else if (mkdir(path, 0777)) {
*pos = '/';
return -1;
}
else if (adjust_shared_perm(path)) {
*pos = '/';
return -2;
}
*pos++ = '/';
}
return 0;
}

char * sha1_to_hex(const unsigned char *sha1)
{
static int bufno;
static char hexbuffer[4][50];
static const char hex[] = "0123456789abcdef";
char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
int i;

for (i = 0; i < 20; i++) {
unsigned int val = *sha1++;
*buf++ = hex[val >> 4];
*buf++ = hex[val & 0xf];
}
*buf = '\0';

return buffer;
}

static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
{
int i;
for (i = 0; i < 20; i++) {
static char hex[] = "0123456789abcdef";
unsigned int val = sha1[i];
char *pos = pathbuf + i*2 + (i > 0);
*pos++ = hex[val >> 4];
*pos = hex[val & 0xf];
}
}

/*
* NOTE! This returns a statically allocated buffer, so you have to be
* careful about using it. Do a "xstrdup()" if you need to save the
* filename.
*
* Also note that this returns the location for creating. Reading
* SHA1 file can happen from any alternate directory listed in the
* DB_ENVIRONMENT environment variable if it is not found in
* the primary object database.
*/
char *sha1_file_name(const unsigned char *sha1)
{
static char *name, *base;

if (!base) {
const char *sha1_file_directory = get_object_directory();
int len = strlen(sha1_file_directory);
base = xmalloc(len + 60);
memcpy(base, sha1_file_directory, len);
memset(base+len, 0, 60);
base[len] = '/';
base[len+3] = '/';
name = base + len + 1;
}
fill_sha1_path(name, sha1);
return base;
}

char *sha1_pack_name(const unsigned char *sha1)
{
static const char hex[] = "0123456789abcdef";
static char *name, *base, *buf;
int i;

if (!base) {
const char *sha1_file_directory = get_object_directory();
int len = strlen(sha1_file_directory);
base = xmalloc(len + 60);
sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
name = base + len + 11;
}

buf = name;

for (i = 0; i < 20; i++) {
unsigned int val = *sha1++;
*buf++ = hex[val >> 4];
*buf++ = hex[val & 0xf];
}

return base;
}

char *sha1_pack_index_name(const unsigned char *sha1)
{
static const char hex[] = "0123456789abcdef";
static char *name, *base, *buf;
int i;

if (!base) {
const char *sha1_file_directory = get_object_directory();
int len = strlen(sha1_file_directory);
base = xmalloc(len + 60);
sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
name = base + len + 11;
}

buf = name;

for (i = 0; i < 20; i++) {
unsigned int val = *sha1++;
*buf++ = hex[val >> 4];
*buf++ = hex[val & 0xf];
}

return base;
}

struct alternate_object_database *alt_odb_list;
static struct alternate_object_database **alt_odb_tail;

static void read_info_alternates(const char * alternates, int depth);

/*
* Prepare alternate object database registry.
*
* The variable alt_odb_list points at the list of struct
* alternate_object_database. The elements on this list come from
* non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
* environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
* whose contents is similar to that environment variable but can be
* LF separated. Its base points at a statically allocated buffer that
* contains "/the/directory/corresponding/to/.git/objects/...", while
* its name points just after the slash at the end of ".git/objects/"
* in the example above, and has enough space to hold 40-byte hex
* SHA1, an extra slash for the first level indirection, and the
* terminating NUL.
*/
static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
{
struct stat st;
const char *objdir = get_object_directory();
struct alternate_object_database *ent;
struct alternate_object_database *alt;
/* 43 = 40-byte + 2 '/' + terminating NUL */
int pfxlen = len;
int entlen = pfxlen + 43;
int base_len = -1;

if (*entry != '/' && relative_base) {
/* Relative alt-odb */
if (base_len < 0)
base_len = strlen(relative_base) + 1;
entlen += base_len;
pfxlen += base_len;
}
ent = xmalloc(sizeof(*ent) + entlen);

if (*entry != '/' && relative_base) {
memcpy(ent->base, relative_base, base_len - 1);
ent->base[base_len - 1] = '/';
memcpy(ent->base + base_len, entry, len);
}
else
memcpy(ent->base, entry, pfxlen);

ent->name = ent->base + pfxlen + 1;
ent->base[pfxlen + 3] = '/';
ent->base[pfxlen] = ent->base[entlen-1] = 0;

/* Detect cases where alternate disappeared */
if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
error("object directory %s does not exist; "
"check .git/objects/info/alternates.",
ent->base);
free(ent);
return -1;
}

/* Prevent the common mistake of listing the same
* thing twice, or object directory itself.
*/
for (alt = alt_odb_list; alt; alt = alt->next) {
if (!memcmp(ent->base, alt->base, pfxlen)) {
free(ent);
return -1;
}
}
if (!memcmp(ent->base, objdir, pfxlen)) {
free(ent);
return -1;
}

/* add the alternate entry */
*alt_odb_tail = ent;
alt_odb_tail = &(ent->next);
ent->next = NULL;

/* recursively add alternates */
read_info_alternates(ent->base, depth + 1);

ent->base[pfxlen] = '/';

return 0;
}

static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
const char *relative_base, int depth)
{
const char *cp, *last;

if (depth > 5) {
error("%s: ignoring alternate object stores, nesting too deep.",
relative_base);
return;
}

last = alt;
while (last < ep) {
cp = last;
if (cp < ep && *cp == '#') {
while (cp < ep && *cp != sep)
cp++;
last = cp + 1;
continue;
}
while (cp < ep && *cp != sep)
cp++;
if (last != cp) {
if ((*last != '/') && depth) {
error("%s: ignoring relative alternate object store %s",
relative_base, last);
} else {
link_alt_odb_entry(last, cp - last,
relative_base, depth);
}
}
while (cp < ep && *cp == sep)
cp++;
last = cp;
}
}

static void read_info_alternates(const char * relative_base, int depth)
{
char *map;
struct stat st;
char path[PATH_MAX];
int fd;

sprintf(path, "%s/info/alternates", relative_base);
fd = open(path, O_RDONLY);
if (fd < 0)
return;
if (fstat(fd, &st) || (st.st_size == 0)) {
close(fd);
return;
}
map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
return;

link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);

munmap(map, st.st_size);
}

void prepare_alt_odb(void)
{
const char *alt;

alt = getenv(ALTERNATE_DB_ENVIRONMENT);
if (!alt) alt = "";

if (alt_odb_tail)
return;
alt_odb_tail = &alt_odb_list;
link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);

read_info_alternates(get_object_directory(), 0);
}

static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
{
char *name = sha1_file_name(sha1);
struct alternate_object_database *alt;

if (!stat(name, st))
return name;
prepare_alt_odb();
for (alt = alt_odb_list; alt; alt = alt->next) {
name = alt->name;
fill_sha1_path(name, sha1);
if (!stat(alt->base, st))
return alt->base;
}
return NULL;
}

#define PACK_MAX_SZ (1<<26)
static int pack_used_ctr;
static unsigned long pack_mapped;
struct packed_git *packed_git;

static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
void **idx_map_)
{
void *idx_map;
unsigned int *index;
unsigned long idx_size;
int nr, i;
int fd = open(path, O_RDONLY);
struct stat st;
if (fd < 0)
return -1;
if (fstat(fd, &st)) {
close(fd);
return -1;
}
idx_size = st.st_size;
idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (idx_map == MAP_FAILED)
return -1;

index = idx_map;
*idx_map_ = idx_map;
*idx_size_ = idx_size;

/* check index map */
if (idx_size < 4*256 + 20 + 20)
return error("index file too small");
nr = 0;
for (i = 0; i < 256; i++) {
unsigned int n = ntohl(index[i]);
if (n < nr)
return error("non-monotonic index");
nr = n;
}

/*
* 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)
return error("wrong index file size");

return 0;
}

static int unuse_one_packed_git(void)
{
struct packed_git *p, *lru = NULL;

for (p = packed_git; p; p = p->next) {
if (p->pack_use_cnt || !p->pack_base)
continue;
if (!lru || p->pack_last_used < lru->pack_last_used)
lru = p;
}
if (!lru)
return 0;
munmap(lru->pack_base, lru->pack_size);
lru->pack_base = NULL;
return 1;
}

void unuse_packed_git(struct packed_git *p)
{
p->pack_use_cnt--;
}

int use_packed_git(struct packed_git *p)
{
if (!p->pack_size) {
struct stat st;
/* We created the struct before we had the pack */
stat(p->pack_name, &st);
if (!S_ISREG(st.st_mode))
die("packfile %s not a regular file", p->pack_name);
p->pack_size = st.st_size;
}
if (!p->pack_base) {
int fd;
struct stat st;
void *map;
struct pack_header *hdr;

pack_mapped += p->pack_size;
while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
; /* nothing */
fd = open(p->pack_name, O_RDONLY);
if (fd < 0)
die("packfile %s cannot be opened", p->pack_name);
if (fstat(fd, &st)) {
close(fd);
die("packfile %s cannot be opened", p->pack_name);
}
if (st.st_size != p->pack_size)
die("packfile %s size mismatch.", p->pack_name);
map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
die("packfile %s cannot be mapped.", p->pack_name);
p->pack_base = map;

/* Check if we understand this pack file. If we don't we're
* likely too old to handle it.
*/
hdr = map;
if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
die("packfile %s isn't actually a pack.", p->pack_name);
if (!pack_version_ok(hdr->hdr_version))
die("packfile %s is version %i and not supported"
" (try upgrading GIT to a newer version)",
p->pack_name, ntohl(hdr->hdr_version));

/* Check if the pack file matches with the index file.
* this is cheap.
*/
if (hashcmp((unsigned char *)(p->index_base) +
p->index_size - 40,
(unsigned char *)p->pack_base +
p->pack_size - 20)) {
die("packfile %s does not match index.", p->pack_name);
}
}
p->pack_last_used = pack_used_ctr++;
p->pack_use_cnt++;
return 0;
}

struct packed_git *add_packed_git(char *path, int path_len, int local)
{
struct stat st;
struct packed_git *p;
unsigned long idx_size;
void *idx_map;
unsigned char sha1[20];

if (check_packed_git_idx(path, &idx_size, &idx_map))
return NULL;

/* do we have a corresponding .pack file? */
strcpy(path + path_len - 4, ".pack");
if (stat(path, &st) || !S_ISREG(st.st_mode)) {
munmap(idx_map, idx_size);
return NULL;
}
/* ok, it looks sane as far as we can check without
* actually mapping the pack file.
*/
p = xmalloc(sizeof(*p) + path_len + 2);
strcpy(p->pack_name, path);
p->index_size = idx_size;
p->pack_size = st.st_size;
p->index_base = idx_map;
p->next = NULL;
p->pack_base = NULL;
p->pack_last_used = 0;
p->pack_use_cnt = 0;
p->pack_local = local;
if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
hashcpy(p->sha1, sha1);
return p;
}

struct packed_git *parse_pack_index(unsigned char *sha1)
{
char *path = sha1_pack_index_name(sha1);
return parse_pack_index_file(sha1, path);
}

struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
{
struct packed_git *p;
unsigned long idx_size;
void *idx_map;
char *path;

if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
return NULL;

path = sha1_pack_name(sha1);

p = xmalloc(sizeof(*p) + strlen(path) + 2);
strcpy(p->pack_name, path);
p->index_size = idx_size;
p->pack_size = 0;
p->index_base = idx_map;
p->next = NULL;
p->pack_base = NULL;
p->pack_last_used = 0;
p->pack_use_cnt = 0;
hashcpy(p->sha1, sha1);
return p;
}

void install_packed_git(struct packed_git *pack)
{
pack->next = packed_git;
packed_git = pack;
}

static void prepare_packed_git_one(char *objdir, int local)
{
char path[PATH_MAX];
int len;
DIR *dir;
struct dirent *de;

sprintf(path, "%s/pack", objdir);
len = strlen(path);
dir = opendir(path);
if (!dir) {
if (errno != ENOENT)
error("unable to open object pack directory: %s: %s",
path, strerror(errno));
return;
}
path[len++] = '/';
while ((de = readdir(dir)) != NULL) {
int namelen = strlen(de->d_name);
struct packed_git *p;

if (!has_extension(de->d_name, ".idx"))
continue;

/* we have .idx. Is it a file we can map? */
strcpy(path + len, de->d_name);
for (p = packed_git; p; p = p->next) {
if (!memcmp(path, p->pack_name, len + namelen - 4))
break;
}
if (p)
continue;
p = add_packed_git(path, len + namelen, local);
if (!p)
continue;
p->next = packed_git;
packed_git = p;
}
closedir(dir);
}

static int prepare_packed_git_run_once = 0;
void prepare_packed_git(void)
{
struct alternate_object_database *alt;

if (prepare_packed_git_run_once)
return;
prepare_packed_git_one(get_object_directory(), 1);
prepare_alt_odb();
for (alt = alt_odb_list; alt; alt = alt->next) {
alt->name[-1] = 0;
prepare_packed_git_one(alt->base, 0);
alt->name[-1] = '/';
}
prepare_packed_git_run_once = 1;
}

static void reprepare_packed_git(void)
{
prepare_packed_git_run_once = 0;
prepare_packed_git();
}

int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
{
unsigned char real_sha1[20];
hash_sha1_file(map, size, type, real_sha1);
return hashcmp(sha1, real_sha1) ? -1 : 0;
}

void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
{
struct stat st;
void *map;
int fd;
char *filename = find_sha1_file(sha1, &st);

if (!filename) {
return NULL;
}

fd = open(filename, O_RDONLY | sha1_file_open_flag);
if (fd < 0) {
/* See if it works without O_NOATIME */
switch (sha1_file_open_flag) {
default:
fd = open(filename, O_RDONLY);
if (fd >= 0)
break;
/* Fallthrough */
case 0:
return NULL;
}

/* If it failed once, it will probably fail again.
* Stop using O_NOATIME
*/
sha1_file_open_flag = 0;
}
map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
return NULL;
*size = st.st_size;
return map;
}

int legacy_loose_object(unsigned char *map)
{
unsigned int word;

/*
* Is it a zlib-compressed buffer? If so, the first byte
* must be 0x78 (15-bit window size, deflated), and the
* first 16-bit word is evenly divisible by 31
*/
word = (map[0] << 8) + map[1];
if (map[0] == 0x78 && !(word % 31))
return 1;
else
return 0;
}

unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep)
{
unsigned shift;
unsigned char c;
unsigned long size;
unsigned long used = 0;

c = buf[used++];
*type = (c >> 4) & 7;
size = c & 15;
shift = 4;
while (c & 0x80) {
if (len <= used)
return 0;
if (sizeof(long) * 8 <= shift)
return 0;
c = buf[used++];
size += (c & 0x7f) << shift;
shift += 7;
}
*sizep = size;
return used;
}

static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
{
unsigned long size, used;
static const char valid_loose_object_type[8] = {
0, /* OBJ_EXT */
1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
0, /* "delta" and others are invalid in a loose object */
};
enum object_type type;

/* Get the data stream */
memset(stream, 0, sizeof(*stream));
stream->next_in = map;
stream->avail_in = mapsize;
stream->next_out = buffer;
stream->avail_out = bufsiz;

if (legacy_loose_object(map)) {
inflateInit(stream);
return inflate(stream, 0);
}

used = unpack_object_header_gently(map, mapsize, &type, &size);
if (!used || !valid_loose_object_type[type])
return -1;
map += used;
mapsize -= used;

/* Set up the stream for the rest.. */
stream->next_in = map;
stream->avail_in = mapsize;
inflateInit(stream);

/* And generate the fake traditional header */
stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
type_names[type], size);
return 0;
}

static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
{
int bytes = strlen(buffer) + 1;
unsigned char *buf = xmalloc(1+size);
unsigned long n;

n = stream->total_out - bytes;
if (n > size)
n = size;
memcpy(buf, (char *) buffer + bytes, n);
bytes = n;
if (bytes < size) {
stream->next_out = buf + bytes;
stream->avail_out = size - bytes;
while (inflate(stream, Z_FINISH) == Z_OK)
/* nothing */;
}
buf[size] = 0;
inflateEnd(stream);
return buf;
}

/*
* We used to just use "sscanf()", but that's actually way
* too permissive for what we want to check. So do an anal
* object header parse by hand.
*/
static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
{
int i;
unsigned long size;

/*
* The type can be at most ten bytes (including the
* terminating '\0' that we add), and is followed by
* a space.
*/
i = 10;
for (;;) {
char c = *hdr++;
if (c == ' ')
break;
if (!--i)
return -1;
*type++ = c;
}
*type = 0;

/*
* The length must follow immediately, and be in canonical
* decimal format (ie "010" is not valid).
*/
size = *hdr++ - '0';
if (size > 9)
return -1;
if (size) {
for (;;) {
unsigned long c = *hdr - '0';
if (c > 9)
break;
hdr++;
size = size * 10 + c;
}
}
*sizep = size;

/*
* The length must be followed by a zero byte
*/
return *hdr ? -1 : 0;
}

void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
{
int ret;
z_stream stream;
char hdr[8192];

ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
return NULL;

return unpack_sha1_rest(&stream, hdr, *size);
}

/* forward declaration for a mutually recursive function */
static int packed_object_info(struct packed_git *p, unsigned long offset,
char *type, unsigned long *sizep);

static int packed_delta_info(struct packed_git *p,
unsigned long offset,
char *type,
unsigned long *sizep)
{
unsigned long base_offset;
unsigned char *base_sha1 = (unsigned char *) p->pack_base + offset;

if (p->pack_size < offset + 20)
die("truncated pack file");
/* The base entry _must_ be in the same pack */
base_offset = find_pack_entry_one(base_sha1, p);
if (!base_offset)
die("failed to find delta-pack base object %s",
sha1_to_hex(base_sha1));
offset += 20;

/* We choose to only get the type of the base object and
* ignore potentially corrupt pack file that expects the delta
* based on a base with a wrong size. This saves tons of
* inflate() calls.
*/
if (packed_object_info(p, base_offset, type, NULL))
die("cannot get info for delta-pack base");

if (sizep) {
const unsigned char *data;
unsigned char delta_head[20];
unsigned long result_size;
z_stream stream;
int st;

memset(&stream, 0, sizeof(stream));

stream.next_in = (unsigned char *) p->pack_base + offset;
stream.avail_in = p->pack_size - offset;
stream.next_out = delta_head;
stream.avail_out = sizeof(delta_head);

inflateInit(&stream);
st = inflate(&stream, Z_FINISH);
inflateEnd(&stream);
if ((st != Z_STREAM_END) &&
stream.total_out != sizeof(delta_head))
die("delta data unpack-initial failed");

/* Examine the initial part of the delta to figure out
* the result size.
*/
data = delta_head;

/* ignore base size */
get_delta_hdr_size(&data, delta_head+sizeof(delta_head));

/* Read the result size */
result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
*sizep = result_size;
}
return 0;
}

static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
enum object_type *type, unsigned long *sizep)
{
unsigned long used;

if (p->pack_size <= offset)
die("object offset outside of pack file");

used = unpack_object_header_gently((unsigned char *)p->pack_base +
offset,
p->pack_size - offset, type, sizep);
if (!used)
die("object offset outside of pack file");

return offset + used;
}

int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
unsigned char *base, unsigned long *sizep,
enum object_type *kindp)
{
unsigned long ptr;
int status = -1;

use_packed_git(p);
ptr = offset;
ptr = unpack_object_header(p, ptr, kindp, sizep);
if (*kindp != OBJ_DELTA)
goto done;
hashcpy(base, (unsigned char *) p->pack_base + ptr);
status = 0;
 done:
unuse_packed_git(p);
return status;
}

void packed_object_info_detail(struct packed_git *p,
unsigned long offset,
char *type,
unsigned long *size,
unsigned long *store_size,
unsigned int *delta_chain_length,
unsigned char *base_sha1)
{
unsigned long val;
unsigned char *next_sha1;
enum object_type kind;

*delta_chain_length = 0;
offset = unpack_object_header(p, offset, &kind, size);

for (;;) {
switch (kind) {
default:
die("corrupted pack file %s containing object of kind %d",
p->pack_name, kind);
case OBJ_COMMIT:
case OBJ_TREE:
case OBJ_BLOB:
case OBJ_TAG:
strcpy(type, type_names[kind]);
*store_size = 0; /* notyet */
return;
case OBJ_DELTA:
if (p->pack_size <= offset + 20)
die("pack file %s records an incomplete delta base",
p->pack_name);
next_sha1 = (unsigned char *) p->pack_base + offset;
if (*delta_chain_length == 0)
hashcpy(base_sha1, next_sha1);
offset = find_pack_entry_one(next_sha1, p);
break;
}
offset = unpack_object_header(p, offset, &kind, &val);
(*delta_chain_length)++;
}
}

static int packed_object_info(struct packed_git *p, unsigned long offset,
char *type, unsigned long *sizep)
{
unsigned long size;
enum object_type kind;

offset = unpack_object_header(p, offset, &kind, &size);

if (kind == OBJ_DELTA)
return packed_delta_info(p, offset, type, sizep);

switch (kind) {
case OBJ_COMMIT:
case OBJ_TREE:
case OBJ_BLOB:
case OBJ_TAG:
strcpy(type, type_names[kind]);
break;
default:
die("corrupted pack file %s containing object of kind %d",
p->pack_name, kind);
}
if (sizep)
*sizep = size;
return 0;
}

static void *unpack_compressed_entry(struct packed_git *p,
unsigned long offset,
unsigned long size)
{
int st;
z_stream stream;
unsigned char *buffer;

buffer = xmalloc(size + 1);
buffer[size] = 0;
memset(&stream, 0, sizeof(stream));
stream.next_in = (unsigned char*)p->pack_base + offset;
stream.avail_in = p->pack_size - offset;
stream.next_out = buffer;
stream.avail_out = size;

inflateInit(&stream);
st = inflate(&stream, Z_FINISH);
inflateEnd(&stream);
if ((st != Z_STREAM_END) || stream.total_out != size) {
free(buffer);
return NULL;
}

return buffer;
}

static void *unpack_delta_entry(struct packed_git *p,
unsigned long offset,
unsigned long delta_size,
char *type,
unsigned long *sizep)
{
void *delta_data, *result, *base;
unsigned long result_size, base_size, base_offset;
unsigned char *base_sha1;

if (p->pack_size < offset + 20)
die("truncated pack file");
/* The base entry _must_ be in the same pack */
base_sha1 = (unsigned char*)p->pack_base + offset;
base_offset = find_pack_entry_one(base_sha1, p);
if (!base_offset)
die("failed to find delta-pack base object %s",
sha1_to_hex(base_sha1));
offset += 20;

base = unpack_entry_gently(p, base_offset, type, &base_size);
if (!base)
die("failed to read delta base object at %lu from %s",
base_offset, p->pack_name);

delta_data = unpack_compressed_entry(p, offset, delta_size);
result = patch_delta(base, base_size,
delta_data, delta_size,
&result_size);
if (!result)
die("failed to apply delta");
free(delta_data);
free(base);
*sizep = result_size;
return result;
}

static void *unpack_entry(struct pack_entry *entry,
char *type, unsigned long *sizep)
{
struct packed_git *p = entry->p;
void *retval;

if (use_packed_git(p))
die("cannot map packed file");
retval = unpack_entry_gently(p, entry->offset, type, sizep);
unuse_packed_git(p);
if (!retval)
die("corrupted pack file %s", p->pack_name);
return retval;
}

/* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
void *unpack_entry_gently(struct packed_git *p, unsigned long offset,
char *type, unsigned long *sizep)
{
unsigned long size;
enum object_type kind;

offset = unpack_object_header(p, offset, &kind, &size);
switch (kind) {
case OBJ_DELTA:
return unpack_delta_entry(p, offset, size, type, sizep);
case OBJ_COMMIT:
case OBJ_TREE:
case OBJ_BLOB:
case OBJ_TAG:
strcpy(type, type_names[kind]);
*sizep = size;
return unpack_compressed_entry(p, offset, size);
default:
return NULL;
}
}

int num_packed_objects(const struct packed_git *p)
{
/* See check_packed_git_idx() */
return (p->index_size - 20 - 20 - 4*256) / 24;
}

int nth_packed_object_sha1(const struct packed_git *p, int n,
unsigned char* sha1)
{
void *index = p->index_base + 256;
if (n < 0 || num_packed_objects(p) <= n)
return -1;
hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
return 0;
}

unsigned long find_pack_entry_one(const unsigned char *sha1,
struct packed_git *p)
{
unsigned int *level1_ofs = p->index_base;
int hi = ntohl(level1_ofs[*sha1]);
int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
void *index = p->index_base + 256;

do {
int mi = (lo + hi) / 2;
int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
if (!cmp)
return ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
if (cmp > 0)
hi = mi;
else
lo = mi+1;
} while (lo < hi);
return 0;
}

static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
{
struct packed_git *p;
unsigned long offset;

prepare_packed_git();

for (p = packed_git; p; p = p->next) {
if (ignore_packed) {
const char **ig;
for (ig = ignore_packed; *ig; ig++)
if (!strcmp(p->pack_name, *ig))
break;
if (*ig)
continue;
}
offset = find_pack_entry_one(sha1, p);
if (offset) {
e->offset = offset;
e->p = p;
hashcpy(e->sha1, sha1);
return 1;
}
}
return 0;
}

struct packed_git *find_sha1_pack(const unsigned char *sha1,
struct packed_git *packs)
{
struct packed_git *p;

for (p = packs; p; p = p->next) {
if (find_pack_entry_one(sha1, p))
return p;
}
return NULL;

}

int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
{
int status;
unsigned long mapsize, size;
void *map;
z_stream stream;
char hdr[128];

map = map_sha1_file(sha1, &mapsize);
if (!map) {
struct pack_entry e;

if (!find_pack_entry(sha1, &e, NULL)) {
reprepare_packed_git();
if (!find_pack_entry(sha1, &e, NULL))
return error("unable to find %s", sha1_to_hex(sha1));
}
if (use_packed_git(e.p))
die("cannot map packed file");
status = packed_object_info(e.p, e.offset, type, sizep);
unuse_packed_git(e.p);
return status;
}
if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
status = error("unable to unpack %s header",
sha1_to_hex(sha1));
if (parse_sha1_header(hdr, type, &size) < 0)
status = error("unable to parse %s header", sha1_to_hex(sha1));
else {
status = 0;
if (sizep)
*sizep = size;
}
inflateEnd(&stream);
munmap(map, mapsize);
return status;
}

static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
{
struct pack_entry e;

if (!find_pack_entry(sha1, &e, NULL)) {
error("cannot read sha1_file for %s", sha1_to_hex(sha1));
return NULL;
}
return unpack_entry(&e, type, size);
}

void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
{
unsigned long mapsize;
void *map, *buf;
struct pack_entry e;

if (find_pack_entry(sha1, &e, NULL))
return read_packed_sha1(sha1, type, size);
map = map_sha1_file(sha1, &mapsize);
if (map) {
buf = unpack_sha1_file(map, mapsize, type, size);
munmap(map, mapsize);
return buf;
}
reprepare_packed_git();
if (find_pack_entry(sha1, &e, NULL))
return read_packed_sha1(sha1, type, size);
return NULL;
}

void *read_object_with_reference(const unsigned char *sha1,
const char *required_type,
unsigned long *size,
unsigned char *actual_sha1_return)
{
char type[20];
void *buffer;
unsigned long isize;
unsigned char actual_sha1[20];

hashcpy(actual_sha1, sha1);
while (1) {
int ref_length = -1;
const char *ref_type = NULL;

buffer = read_sha1_file(actual_sha1, type, &isize);
if (!buffer)
return NULL;
if (!strcmp(type, required_type)) {
*size = isize;
if (actual_sha1_return)
hashcpy(actual_sha1_return, actual_sha1);
return buffer;
}
/* Handle references */
else if (!strcmp(type, commit_type))
ref_type = "tree ";
else if (!strcmp(type, tag_type))
ref_type = "object ";
else {
free(buffer);
return NULL;
}
ref_length = strlen(ref_type);

if (memcmp(buffer, ref_type, ref_length) ||
get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
free(buffer);
return NULL;
}
free(buffer);
/* Now we have the ID of the referred-to object in
* actual_sha1. Check again. */
}
}

static void write_sha1_file_prepare(void *buf, unsigned long len,
                                    const char *type, unsigned char *sha1,
                                    unsigned char *hdr, int *hdrlen)
{
SHA_CTX c;

/* Generate the header */
*hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;

/* Sha1.. */
SHA1_Init(&c);
SHA1_Update(&c, hdr, *hdrlen);
SHA1_Update(&c, buf, len);
SHA1_Final(sha1, &c);
}

/*
* Link the tempfile to the final place, possibly creating the
* last directory level as you do so.
*
* Returns the errno on failure, 0 on success.
*/
static int link_temp_to_file(const char *tmpfile, const char *filename)
{
int ret;
char *dir;

if (!link(tmpfile, filename))
return 0;

/*
* Try to mkdir the last path component if that failed.
*
* Re-try the "link()" regardless of whether the mkdir
* succeeds, since a race might mean that somebody
* else succeeded.
*/
ret = errno;
dir = strrchr(filename, '/');
if (dir) {
*dir = 0;
mkdir(filename, 0777);
if (adjust_shared_perm(filename))
return -2;
*dir = '/';
if (!link(tmpfile, filename))
return 0;
ret = errno;
}
return ret;
}

/*
* Move the just written object into its final resting place
*/
int move_temp_to_file(const char *tmpfile, const char *filename)
{
int ret = link_temp_to_file(tmpfile, filename);

/*
* Coda hack - coda doesn't like cross-directory links,
* so we fall back to a rename, which will mean that it
* won't be able to check collisions, but that's not a
* big deal.
*
* The same holds for FAT formatted media.
*
* When this succeeds, we just return 0. We have nothing
* left to unlink.
*/
if (ret && ret != EEXIST) {
if (!rename(tmpfile, filename))
return 0;
ret = errno;
}
unlink(tmpfile);
if (ret) {
if (ret != EEXIST) {
fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
return -1;
}
/* FIXME!!! Collision check here ? */
}

return 0;
}

static int write_buffer(int fd, const void *buf, size_t len)
{
while (len) {
ssize_t size;

size = write(fd, buf, len);
if (!size)
return error("file write: disk full");
if (size < 0) {
if (errno == EINTR || errno == EAGAIN)
continue;
return error("file write error (%s)", strerror(errno));
}
len -= size;
buf = (char *) buf + size;
}
return 0;
}

static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
{
int hdr_len;
unsigned char c;

c = (type << 4) | (len & 15);
len >>= 4;
hdr_len = 1;
while (len) {
*hdr++ = c | 0x80;
hdr_len++;
c = (len & 0x7f);
len >>= 7;
}
*hdr = c;
return hdr_len;
}

static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
{
int obj_type, hdr;

if (use_legacy_headers) {
while (deflate(stream, 0) == Z_OK)
/* nothing */;
return;
}
if (!strcmp(type, blob_type))
obj_type = OBJ_BLOB;
else if (!strcmp(type, tree_type))
obj_type = OBJ_TREE;
else if (!strcmp(type, commit_type))
obj_type = OBJ_COMMIT;
else if (!strcmp(type, tag_type))
obj_type = OBJ_TAG;
else
die("trying to generate bogus object of type '%s'", type);
hdr = write_binary_header(stream->next_out, obj_type, len);
stream->total_out = hdr;
stream->next_out += hdr;
stream->avail_out -= hdr;
}

int hash_sha1_file(void *buf, unsigned long len, const char *type,
                   unsigned char *sha1)
{
unsigned char hdr[50];
int hdrlen;
write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
return 0;
}

int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
{
int size;
unsigned char *compressed;
z_stream stream;
unsigned char sha1[20];
char *filename;
static char tmpfile[PATH_MAX];
unsigned char hdr[50];
int fd, hdrlen;

/* Normally if we have it in the pack then we do not bother writing
* it out into .git/objects/??/?{38} file.
*/
write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
filename = sha1_file_name(sha1);
if (returnsha1)
hashcpy(returnsha1, sha1);
if (has_sha1_file(sha1))
return 0;
fd = open(filename, O_RDONLY);
if (fd >= 0) {
/*
* FIXME!!! We might do collision checking here, but we'd
* need to uncompress the old file and check it. Later.
*/
close(fd);
return 0;
}

if (errno != ENOENT) {
fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
return -1;
}

snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());

fd = mkstemp(tmpfile);
if (fd < 0) {
fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
return -1;
}

/* Set it up */
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, zlib_compression_level);
size = 8 + deflateBound(&stream, len+hdrlen);
compressed = xmalloc(size);

/* Compress it */
stream.next_out = compressed;
stream.avail_out = size;

/* First header.. */
stream.next_in = hdr;
stream.avail_in = hdrlen;
setup_object_header(&stream, type, len);

/* Then the data itself.. */
stream.next_in = buf;
stream.avail_in = len;
while (deflate(&stream, Z_FINISH) == Z_OK)
/* nothing */;
deflateEnd(&stream);
size = stream.total_out;

if (write_buffer(fd, compressed, size) < 0)
die("unable to write sha1 file");
fchmod(fd, 0444);
close(fd);
free(compressed);

return move_temp_to_file(tmpfile, filename);
}

/*
* We need to unpack and recompress the object for writing
* it out to a different file.
*/
static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
{
size_t size;
z_stream stream;
unsigned char *unpacked;
unsigned long len;
char type[20];
char hdr[50];
int hdrlen;
void *buf;

/* need to unpack and recompress it by itself */
unpacked = read_packed_sha1(sha1, type, &len);

hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;

/* Set it up */
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, zlib_compression_level);
size = deflateBound(&stream, len + hdrlen);
buf = xmalloc(size);

/* Compress it */
stream.next_out = buf;
stream.avail_out = size;

/* First header.. */
stream.next_in = (void *)hdr;
stream.avail_in = hdrlen;
while (deflate(&stream, 0) == Z_OK)
/* nothing */;

/* Then the data itself.. */
stream.next_in = unpacked;
stream.avail_in = len;
while (deflate(&stream, Z_FINISH) == Z_OK)
/* nothing */;
deflateEnd(&stream);
free(unpacked);

*objsize = stream.total_out;
return buf;
}

int write_sha1_to_fd(int fd, const unsigned char *sha1)
{
int retval;
unsigned long objsize;
void *buf = map_sha1_file(sha1, &objsize);

if (buf) {
retval = write_buffer(fd, buf, objsize);
munmap(buf, objsize);
return retval;
}

buf = repack_object(sha1, &objsize);
retval = write_buffer(fd, buf, objsize);
free(buf);
return retval;
}

int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
size_t bufsize, size_t *bufposn)
{
char tmpfile[PATH_MAX];
int local;
z_stream stream;
unsigned char real_sha1[20];
unsigned char discard[4096];
int ret;
SHA_CTX c;

snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());

local = mkstemp(tmpfile);
if (local < 0)
return error("Couldn't open %s for %s",
tmpfile, sha1_to_hex(sha1));

memset(&stream, 0, sizeof(stream));

inflateInit(&stream);

SHA1_Init(&c);

do {
ssize_t size;
if (*bufposn) {
stream.avail_in = *bufposn;
stream.next_in = (unsigned char *) buffer;
do {
stream.next_out = discard;
stream.avail_out = sizeof(discard);
ret = inflate(&stream, Z_SYNC_FLUSH);
SHA1_Update(&c, discard, sizeof(discard) -
stream.avail_out);
} while (stream.avail_in && ret == Z_OK);
if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
die("unable to write sha1 file");
memmove(buffer, buffer + *bufposn - stream.avail_in,
stream.avail_in);
*bufposn = stream.avail_in;
if (ret != Z_OK)
break;
}
size = read(fd, buffer + *bufposn, bufsize - *bufposn);
if (size <= 0) {
close(local);
unlink(tmpfile);
if (!size)
return error("Connection closed?");
perror("Reading from connection");
return -1;
}
*bufposn += size;
} while (1);
inflateEnd(&stream);

close(local);
SHA1_Final(real_sha1, &c);
if (ret != Z_STREAM_END) {
unlink(tmpfile);
return error("File %s corrupted", sha1_to_hex(sha1));
}
if (hashcmp(sha1, real_sha1)) {
unlink(tmpfile);
return error("File %s has bad hash", sha1_to_hex(sha1));
}

return move_temp_to_file(tmpfile, sha1_file_name(sha1));
}

int has_pack_index(const unsigned char *sha1)
{
struct stat st;
if (stat(sha1_pack_index_name(sha1), &st))
return 0;
return 1;
}

int has_pack_file(const unsigned char *sha1)
{
struct stat st;
if (stat(sha1_pack_name(sha1), &st))
return 0;
return 1;
}

int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
{
struct pack_entry e;
return find_pack_entry(sha1, &e, ignore_packed);
}

int has_sha1_file(const unsigned char *sha1)
{
struct stat st;
struct pack_entry e;

if (find_pack_entry(sha1, &e, NULL))
return 1;
return find_sha1_file(sha1, &st) ? 1 : 0;
}

/*
* reads from fd as long as possible into a supplied buffer of size bytes.
* If necessary the buffer's size is increased using realloc()
*
* returns 0 if anything went fine and -1 otherwise
*
* NOTE: both buf and size may change, but even when -1 is returned
* you still have to free() it yourself.
*/
int read_pipe(int fd, char** return_buf, unsigned long* return_size)
{
char* buf = *return_buf;
unsigned long size = *return_size;
int iret;
unsigned long off = 0;

do {
iret = xread(fd, buf + off, size - off);
if (iret > 0) {
off += iret;
if (off == size) {
size *= 2;
buf = xrealloc(buf, size);
}
}
} while (iret > 0);

*return_buf = buf;
*return_size = off;

if (iret < 0)
return -1;
return 0;
}

int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
{
unsigned long size = 4096;
char *buf = xmalloc(size);
int ret;

if (read_pipe(fd, &buf, &size)) {
free(buf);
return -1;
}

if (!type)
type = blob_type;
if (write_object)
ret = write_sha1_file(buf, size, type, sha1);
else
ret = hash_sha1_file(buf, size, type, sha1);
free(buf);
return ret;
}

int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
{
unsigned long size = st->st_size;
void *buf;
int ret;

buf = "";
if (size)
buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (buf == MAP_FAILED)
return -1;

if (!type)
type = blob_type;
if (write_object)
ret = write_sha1_file(buf, size, type, sha1);
else
ret = hash_sha1_file(buf, size, type, sha1);
if (size)
munmap(buf, size);
return ret;
}

int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
{
int fd;
char *target;

switch (st->st_mode & S_IFMT) {
case S_IFREG:
fd = open(path, O_RDONLY);
if (fd < 0)
return error("open(\"%s\"): %s", path,
strerror(errno));
if (index_fd(sha1, fd, st, write_object, NULL) < 0)
return error("%s: failed to insert into database",
path);
break;
case S_IFLNK:
target = xmalloc(st->st_size+1);
if (readlink(path, target, st->st_size+1) != st->st_size) {
char *errstr = strerror(errno);
free(target);
return error("readlink(\"%s\"): %s", path,
errstr);
}
if (!write_object)
hash_sha1_file(target, st->st_size, blob_type, sha1);
else if (write_sha1_file(target, st->st_size, blob_type, sha1))
return error("%s: failed to insert into database",
path);
free(target);
break;
default:
return error("%s: unsupported file type", path);
}
return 0;
}
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