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git/sha1_file.c

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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"
#include "refs.h"
#ifndef O_NOATIME
#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
#define O_NOATIME 01000000
#else
#define O_NOATIME 0
#endif
#endif
#ifdef NO_C99_FORMAT
#define SZ_FMT "lu"
#else
#define SZ_FMT "zu"
#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;
size_t mapsz;
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;
}
mapsz = xsize_t(st.st_size);
map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth);
munmap(map, mapsz);
}
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;
}
static unsigned int pack_used_ctr;
static unsigned int pack_mmap_calls;
static unsigned int peak_pack_open_windows;
static unsigned int pack_open_windows;
static size_t peak_pack_mapped;
static size_t pack_mapped;
struct packed_git *packed_git;
void pack_report()
{
fprintf(stderr,
"pack_report: getpagesize() = %10" SZ_FMT "\n"
"pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
"pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
(size_t) getpagesize(),
packed_git_window_size,
packed_git_limit);
fprintf(stderr,
"pack_report: pack_used_ctr = %10u\n"
"pack_report: pack_mmap_calls = %10u\n"
"pack_report: pack_open_windows = %10u / %10u\n"
"pack_report: pack_mapped = "
"%10" SZ_FMT " / %10" SZ_FMT "\n",
pack_used_ctr,
pack_mmap_calls,
pack_open_windows, peak_pack_open_windows,
pack_mapped, peak_pack_mapped);
}
static int check_packed_git_idx(const char *path, struct packed_git *p)
{
void *idx_map;
struct pack_idx_header *hdr;
size_t idx_size;
uint32_t nr, i, *index;
int fd = open(path, O_RDONLY);
struct stat st;
if (fd < 0)
return -1;
if (fstat(fd, &st)) {
close(fd);
return -1;
}
idx_size = xsize_t(st.st_size);
if (idx_size < 4 * 256 + 20 + 20) {
close(fd);
return error("index file %s is too small", path);
}
idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
/* a future index format would start with this, as older git
* binaries would fail the non-monotonic index check below.
* give a nicer warning to the user if we can.
*/
hdr = idx_map;
if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
munmap(idx_map, idx_size);
return error("index file %s is a newer version"
" and is not supported by this binary"
" (try upgrading GIT to a newer version)",
path);
}
nr = 0;
index = idx_map;
for (i = 0; i < 256; i++) {
uint32_t n = ntohl(index[i]);
if (n < nr) {
munmap(idx_map, idx_size);
return error("non-monotonic index %s", path);
}
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) {
munmap(idx_map, idx_size);
return error("wrong index file size in %s", path);
}
p->index_version = 1;
p->index_data = idx_map;
p->index_size = idx_size;
return 0;
}
static void scan_windows(struct packed_git *p,
struct packed_git **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;
}
}
static int unuse_one_window(struct packed_git *current)
{
struct packed_git *p, *lru_p = NULL;
struct pack_window *lru_w = NULL, *lru_l = NULL;
if (current)
scan_windows(current, &lru_p, &lru_w, &lru_l);
for (p = packed_git; p; p = p->next)
scan_windows(p, &lru_p, &lru_w, &lru_l);
if (lru_p) {
munmap(lru_w->base, lru_w->len);
pack_mapped -= lru_w->len;
if (lru_l)
lru_l->next = lru_w->next;
else {
lru_p->windows = lru_w->next;
if (!lru_p->windows && lru_p != current) {
close(lru_p->pack_fd);
lru_p->pack_fd = -1;
}
}
free(lru_w);
pack_open_windows--;
return 1;
}
return 0;
}
void release_pack_memory(size_t need)
{
size_t cur = pack_mapped;
while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
; /* nothing */
}
void unuse_pack(struct pack_window **w_cursor)
{
struct pack_window *w = *w_cursor;
if (w) {
w->inuse_cnt--;
*w_cursor = NULL;
}
}
/*
* Do not call this directly as this leaks p->pack_fd on error return;
* call open_packed_git() instead.
*/
static int open_packed_git_1(struct packed_git *p)
{
struct stat st;
struct pack_header hdr;
unsigned char sha1[20];
unsigned char *idx_sha1;
long fd_flag;
p->pack_fd = open(p->pack_name, O_RDONLY);
if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
return -1;
/* If we created the struct before we had the pack we lack size. */
if (!p->pack_size) {
if (!S_ISREG(st.st_mode))
return error("packfile %s not a regular file", p->pack_name);
p->pack_size = st.st_size;
} else if (p->pack_size != st.st_size)
return error("packfile %s size changed", p->pack_name);
/* 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 error("cannot set FD_CLOEXEC");
/* Verify we recognize this pack file format. */
if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
return error("file %s is far too short to be a packfile", p->pack_name);
if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
return error("file %s is not a GIT packfile", p->pack_name);
if (!pack_version_ok(hdr.hdr_version))
return error("packfile %s is version %u and not supported"
" (try upgrading GIT to a newer version)",
p->pack_name, ntohl(hdr.hdr_version));
/* Verify the pack matches its index. */
if (num_packed_objects(p) != ntohl(hdr.hdr_entries))
return error("packfile %s claims to have %u objects"
" while index size indicates %u objects",
p->pack_name, ntohl(hdr.hdr_entries),
num_packed_objects(p));
if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
return error("end of packfile %s is unavailable", p->pack_name);
if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
return error("packfile %s signature is unavailable", p->pack_name);
idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
if (hashcmp(sha1, idx_sha1))
return error("packfile %s does not match index", p->pack_name);
return 0;
}
static int open_packed_git(struct packed_git *p)
{
if (!open_packed_git_1(p))
return 0;
if (p->pack_fd != -1) {
close(p->pack_fd);
p->pack_fd = -1;
}
return -1;
}
static int in_window(struct pack_window *win, off_t offset)
{
/* 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) <= (win_off + win->len);
}
unsigned char* use_pack(struct packed_git *p,
struct pack_window **w_cursor,
off_t offset,
unsigned int *left)
{
struct pack_window *win = *w_cursor;
if (p->pack_fd == -1 && open_packed_git(p))
die("packfile %s cannot be accessed", p->pack_name);
/* Since packfiles end in a hash of their content and its
* pointless to ask for an offset into the middle of that
* hash, and the in_window function above wouldn't match
* don't allow an offset too close to the end of the file.
*/
if (offset > (p->pack_size - 20))
die("offset beyond end of packfile (truncated pack?)");
if (!win || !in_window(win, offset)) {
if (win)
win->inuse_cnt--;
for (win = p->windows; win; win = win->next) {
if (in_window(win, offset))
break;
}
if (!win) {
size_t window_align = packed_git_window_size / 2;
off_t len;
win = xcalloc(1, sizeof(*win));
win->offset = (offset / window_align) * window_align;
len = p->pack_size - win->offset;
if (len > packed_git_window_size)
len = packed_git_window_size;
win->len = (size_t)len;
pack_mapped += win->len;
while (packed_git_limit < pack_mapped
&& unuse_one_window(p))
; /* nothing */
win->base = xmmap(NULL, win->len,
PROT_READ, MAP_PRIVATE,
p->pack_fd, win->offset);
if (win->base == MAP_FAILED)
die("packfile %s cannot be mapped: %s",
p->pack_name,
strerror(errno));
pack_mmap_calls++;
pack_open_windows++;
if (pack_mapped > peak_pack_mapped)
peak_pack_mapped = pack_mapped;
if (pack_open_windows > peak_pack_open_windows)
peak_pack_open_windows = pack_open_windows;
win->next = p->windows;
p->windows = win;
}
}
if (win != *w_cursor) {
win->last_used = pack_used_ctr++;
win->inuse_cnt++;
*w_cursor = win;
}
offset -= win->offset;
if (left)
*left = win->len - xsize_t(offset);
return win->base + offset;
}
struct packed_git *add_packed_git(const char *path, int path_len, int local)
{
struct stat st;
struct packed_git *p = xmalloc(sizeof(*p) + path_len + 2);
/*
* Make sure a corresponding .pack file exists and that
* the index looks sane.
*/
path_len -= strlen(".idx");
if (path_len < 1)
return NULL;
memcpy(p->pack_name, path, path_len);
strcpy(p->pack_name + path_len, ".pack");
if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode) ||
check_packed_git_idx(path, p)) {
free(p);
return NULL;
}
/* ok, it looks sane as far as we can check without
* actually mapping the pack file.
*/
p->pack_size = st.st_size;
p->next = NULL;
p->windows = NULL;
p->pack_fd = -1;
p->pack_local = local;
p->mtime = st.st_mtime;
if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
hashclr(p->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,
const char *idx_path)
{
const char *path = sha1_pack_name(sha1);
struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2);
if (check_packed_git_idx(idx_path, p)) {
free(p);
return NULL;
}
strcpy(p->pack_name, path);
p->pack_size = 0;
p->next = NULL;
p->windows = NULL;
p->pack_fd = -1;
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;
/* Don't reopen a pack we already have. */
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;
/* See if it really is a valid .idx file with corresponding
* .pack file that we can map.
*/
p = add_packed_git(path, len + namelen, local);
if (!p)
continue;
install_packed_git(p);
}
closedir(dir);
}
static int sort_pack(const void *a_, const void *b_)
{
struct packed_git *a = *((struct packed_git **)a_);
struct packed_git *b = *((struct packed_git **)b_);
int st;
/*
* 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;
/*
* 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;
return -1;
}
static void rearrange_packed_git(void)
{
struct packed_git **ary, *p;
int i, n;
for (n = 0, p = packed_git; p; p = p->next)
n++;
if (n < 2)
return;
/* prepare an array of packed_git for easier sorting */
ary = xcalloc(n, sizeof(struct packed_git *));
for (n = 0, p = packed_git; p; p = p->next)
ary[n++] = p;
qsort(ary, n, sizeof(struct packed_git *), sort_pack);
/* link them back again */
for (i = 0; i < n - 1; i++)
ary[i]->next = ary[i + 1];
ary[n - 1]->next = NULL;
packed_git = ary[0];
free(ary);
}
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] = '/';
}
rearrange_packed_git();
prepare_packed_git_run_once = 1;
}
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;
}
*size = xsize_t(st.st_size);
map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
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",
typename(type), size);
return 0;
}
static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
{
int bytes = strlen(buffer) + 1;
unsigned char *buf = xmalloc(1+size);
unsigned long n;
int status = Z_OK;
n = stream->total_out - bytes;
if (n > size)
n = size;
memcpy(buf, (char *) buffer + bytes, n);
bytes = n;
if (bytes <= size) {
/*
* The above condition must be (bytes <= size), not
* (bytes < size). In other words, even though we
* expect no more output and set avail_out to zer0,
* the input zlib stream may have bytes that express
* "this concludes the stream", and we *do* want to
* eat that input.
*
* Otherwise we would not be able to test that we
* consumed all the input to reach the expected size;
* we also want to check that zlib tells us that all
* went well with status == Z_STREAM_END at the end.
*/
stream->next_out = buf + bytes;
stream->avail_out = size - bytes;
while (status == Z_OK)
status = inflate(stream, Z_FINISH);
}
buf[size] = 0;
if (status == Z_STREAM_END && !stream->avail_in) {
inflateEnd(stream);
return buf;
}
if (status < 0)
error("corrupt loose object '%s'", sha1_to_hex(sha1));
else if (stream->avail_in)
error("garbage at end of loose object '%s'",
sha1_to_hex(sha1));
free(buf);
return NULL;
}
/*
* 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(const char *hdr, unsigned long *sizep)
{
char type[10];
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 = 0;
for (;;) {
char c = *hdr++;
if (c == ' ')
break;
type[i++] = c;
if (i >= sizeof(type))
return -1;
}
type[i] = 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 : type_from_string(type);
}
static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
{
int ret;
z_stream stream;
char hdr[8192];
ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
return NULL;
return unpack_sha1_rest(&stream, hdr, *size, sha1);
}
static off_t get_delta_base(struct packed_git *p,
struct pack_window **w_curs,
off_t *curpos,
enum object_type type,
off_t delta_obj_offset)
{
unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
off_t base_offset;
/* use_pack() 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 == 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 || base_offset & ~(~0UL >> 7))
die("offset value overflow for delta base object");
c = base_info[used++];
base_offset = (base_offset << 7) + (c & 127);
}
base_offset = delta_obj_offset - base_offset;
if (base_offset >= delta_obj_offset)
die("delta base offset out of bound");
*curpos += used;
} else if (type == OBJ_REF_DELTA) {
/* The base entry _must_ be in the same pack */
base_offset = find_pack_entry_one(base_info, p);
if (!base_offset)
die("failed to find delta-pack base object %s",
sha1_to_hex(base_info));
*curpos += 20;
} else
die("I am totally screwed");
return base_offset;
}
/* forward declaration for a mutually recursive function */
static int packed_object_info(struct packed_git *p, off_t offset,
unsigned long *sizep);
static int packed_delta_info(struct packed_git *p,
struct pack_window **w_curs,
off_t curpos,
enum object_type type,
off_t obj_offset,
unsigned long *sizep)
{
off_t base_offset;
base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
type = packed_object_info(p, base_offset, NULL);
/* 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 (sizep) {
const unsigned char *data;
unsigned char delta_head[20], *in;
z_stream stream;
int st;
memset(&stream, 0, sizeof(stream));
stream.next_out = delta_head;
stream.avail_out = sizeof(delta_head);
inflateInit(&stream);
do {
in = use_pack(p, w_curs, curpos, &stream.avail_in);
stream.next_in = in;
st = inflate(&stream, Z_FINISH);
curpos += stream.next_in - in;
} while ((st == Z_OK || st == Z_BUF_ERROR)
&& stream.total_out < sizeof(delta_head));
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 */
*sizep = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
}
return type;
}
static int unpack_object_header(struct packed_git *p,
struct pack_window **w_curs,
off_t *curpos,
unsigned long *sizep)
{
unsigned char *base;
unsigned int left;
unsigned long used;
enum object_type type;
/* use_pack() 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 = use_pack(p, w_curs, *curpos, &left);
used = unpack_object_header_gently(base, left, &type, sizep);
if (!used)
die("object offset outside of pack file");
*curpos += used;
return type;
}
const char *packed_object_info_detail(struct packed_git *p,
off_t obj_offset,
unsigned long *size,
unsigned long *store_size,
unsigned int *delta_chain_length,
unsigned char *base_sha1)
{
struct pack_window *w_curs = NULL;
off_t curpos;
unsigned long dummy;
unsigned char *next_sha1;
enum object_type type;
*delta_chain_length = 0;
curpos = obj_offset;
type = unpack_object_header(p, &w_curs, &curpos, size);
for (;;) {
switch (type) {
default:
die("pack %s contains unknown object type %d",
p->pack_name, type);
case OBJ_COMMIT:
case OBJ_TREE:
case OBJ_BLOB:
case OBJ_TAG:
*store_size = 0; /* notyet */
unuse_pack(&w_curs);
return typename(type);
case OBJ_OFS_DELTA:
obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
if (*delta_chain_length == 0) {
/* TODO: find base_sha1 as pointed by curpos */
hashclr(base_sha1);
}
break;
case OBJ_REF_DELTA:
next_sha1 = use_pack(p, &w_curs, curpos, NULL);
if (*delta_chain_length == 0)
hashcpy(base_sha1, next_sha1);
obj_offset = find_pack_entry_one(next_sha1, p);
break;
}
(*delta_chain_length)++;
curpos = obj_offset;
type = unpack_object_header(p, &w_curs, &curpos, &dummy);
}
}
static int packed_object_info(struct packed_git *p, off_t obj_offset,
unsigned long *sizep)
{
struct pack_window *w_curs = NULL;
unsigned long size;
off_t curpos = obj_offset;
enum object_type type;
type = unpack_object_header(p, &w_curs, &curpos, &size);
switch (type) {
case OBJ_OFS_DELTA:
case OBJ_REF_DELTA:
type = packed_delta_info(p, &w_curs, curpos,
type, obj_offset, sizep);
break;
case OBJ_COMMIT:
case OBJ_TREE:
case OBJ_BLOB:
case OBJ_TAG:
if (sizep)
*sizep = size;
break;
default:
die("pack %s contains unknown object type %d",
p->pack_name, type);
}
unuse_pack(&w_curs);
return type;
}
static void *unpack_compressed_entry(struct packed_git *p,
struct pack_window **w_curs,
off_t curpos,
unsigned long size)
{
int st;
z_stream stream;
unsigned char *buffer, *in;
buffer = xmalloc(size + 1);
buffer[size] = 0;
memset(&stream, 0, sizeof(stream));
stream.next_out = buffer;
stream.avail_out = size;
inflateInit(&stream);
do {
in = use_pack(p, w_curs, curpos, &stream.avail_in);
stream.next_in = in;
st = inflate(&stream, Z_FINISH);
curpos += stream.next_in - in;
} while (st == Z_OK || st == Z_BUF_ERROR);
inflateEnd(&stream);
if ((st != Z_STREAM_END) || stream.total_out != size) {
free(buffer);
return NULL;
}
return buffer;
}
#define MAX_DELTA_CACHE (256)
static size_t delta_base_cached;
static struct delta_base_cache_lru_list {
struct delta_base_cache_lru_list *prev;
struct delta_base_cache_lru_list *next;
} delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
static struct delta_base_cache_entry {
struct delta_base_cache_lru_list lru;
void *data;
struct packed_git *p;
off_t base_offset;
unsigned long size;
enum object_type type;
} delta_base_cache[MAX_DELTA_CACHE];
static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
{
unsigned long hash;
hash = (unsigned long)p + (unsigned long)base_offset;
hash += (hash >> 8) + (hash >> 16);
return hash % MAX_DELTA_CACHE;
}
static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
unsigned long *base_size, enum object_type *type, int keep_cache)
{
void *ret;
unsigned long hash = pack_entry_hash(p, base_offset);
struct delta_base_cache_entry *ent = delta_base_cache + hash;
ret = ent->data;
if (ret && ent->p == p && ent->base_offset == base_offset)
goto found_cache_entry;
return unpack_entry(p, base_offset, type, base_size);
found_cache_entry:
if (!keep_cache) {
ent->data = NULL;
ent->lru.next->prev = ent->lru.prev;
ent->lru.prev->next = ent->lru.next;
delta_base_cached -= ent->size;
}
else {
ret = xmalloc(ent->size + 1);
memcpy(ret, ent->data, ent->size);
((char *)ret)[ent->size] = 0;
}
*type = ent->type;
*base_size = ent->size;
return ret;
}
static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
{
if (ent->data) {
free(ent->data);
ent->data = NULL;
ent->lru.next->prev = ent->lru.prev;
ent->lru.prev->next = ent->lru.next;
delta_base_cached -= ent->size;
}
}
static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
void *base, unsigned long base_size, enum object_type type)
{
unsigned long hash = pack_entry_hash(p, base_offset);
struct delta_base_cache_entry *ent = delta_base_cache + hash;
struct delta_base_cache_lru_list *lru;
release_delta_base_cache(ent);
delta_base_cached += base_size;
for (lru = delta_base_cache_lru.next;
delta_base_cached > delta_base_cache_limit
&& lru != &delta_base_cache_lru;
lru = lru->next) {
struct delta_base_cache_entry *f = (void *)lru;
if (f->type == OBJ_BLOB)
release_delta_base_cache(f);
}
for (lru = delta_base_cache_lru.next;
delta_base_cached > delta_base_cache_limit
&& lru != &delta_base_cache_lru;
lru = lru->next) {
struct delta_base_cache_entry *f = (void *)lru;
release_delta_base_cache(f);
}
ent->p = p;
ent->base_offset = base_offset;
ent->type = type;
ent->data = base;
ent->size = base_size;
ent->lru.next = &delta_base_cache_lru;
ent->lru.prev = delta_base_cache_lru.prev;
delta_base_cache_lru.prev->next = &ent->lru;
delta_base_cache_lru.prev = &ent->lru;
}
static void *unpack_delta_entry(struct packed_git *p,
struct pack_window **w_curs,
off_t curpos,
unsigned long delta_size,
off_t obj_offset,
enum object_type *type,
unsigned long *sizep)
{
void *delta_data, *result, *base;
unsigned long base_size;
off_t base_offset;
base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
if (!base)
die("failed to read delta base object"
" at %"PRIuMAX" from %s",
(uintmax_t)base_offset, p->pack_name);
delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
result = patch_delta(base, base_size,
delta_data, delta_size,
sizep);
if (!result)
die("failed to apply delta");
free(delta_data);
add_delta_base_cache(p, base_offset, base, base_size, *type);
return result;
}
void *unpack_entry(struct packed_git *p, off_t obj_offset,
enum object_type *type, unsigned long *sizep)
{
struct pack_window *w_curs = NULL;
off_t curpos = obj_offset;
void *data;
*type = unpack_object_header(p, &w_curs, &curpos, sizep);
switch (*type) {
case OBJ_OFS_DELTA:
case OBJ_REF_DELTA:
data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
obj_offset, type, sizep);
break;
case OBJ_COMMIT:
case OBJ_TREE:
case OBJ_BLOB:
case OBJ_TAG:
data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
break;
default:
die("unknown object type %i in %s", *type, p->pack_name);
}
unuse_pack(&w_curs);
return data;
}
uint32_t num_packed_objects(const struct packed_git *p)
{
/* See check_packed_git_idx() */
return (uint32_t)((p->index_size - 20 - 20 - 4*256) / 24);
}
const unsigned char *nth_packed_object_sha1(const struct packed_git *p,
uint32_t n)
{
const unsigned char *index = p->index_data;
index += 4 * 256;
if (num_packed_objects(p) <= n)
return NULL;
return index + 24 * n + 4;
}
off_t find_pack_entry_one(const unsigned char *sha1,
struct packed_git *p)
{
const uint32_t *level1_ofs = p->index_data;
int hi = ntohl(level1_ofs[*sha1]);
int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
const unsigned char *index = p->index_data;
index += 4 * 256;
do {
int mi = (lo + hi) / 2;
int cmp = hashcmp(index + 24 * mi + 4, sha1);
if (!cmp)
return ntohl(*((uint32_t *)((char *)index + (24 * mi))));
if (cmp > 0)
hi = mi;
else
lo = mi+1;
} while (lo < hi);
return 0;
}
static int matches_pack_name(struct packed_git *p, const char *ig)
{
const char *last_c, *c;
if (!strcmp(p->pack_name, ig))
return 0;
for (c = p->pack_name, last_c = c; *c;)
if (*c == '/')
last_c = ++c;
else
++c;
if (!strcmp(last_c, ig))
return 0;
return 1;
}
static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
{
struct packed_git *p;
off_t 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 (!matches_pack_name(p, *ig))
break;
if (*ig)
continue;
}
offset = find_pack_entry_one(sha1, p);
if (offset) {
/*
* We are about to tell the caller where they can
* locate the requested object. We better make
* sure the packfile is still here and can be
* accessed before supplying that answer, as
* it may have been deleted since the index
* was loaded!
*/
if (p->pack_fd == -1 && open_packed_git(p)) {
error("packfile %s cannot be accessed", p->pack_name);
continue;
}
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;
}
static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
{
int status;
unsigned long mapsize, size;
void *map;
z_stream stream;
char hdr[32];
map = map_sha1_file(sha1, &mapsize);
if (!map)
return error("unable to find %s", sha1_to_hex(sha1));
if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
status = error("unable to unpack %s header",
sha1_to_hex(sha1));
else if ((status = parse_sha1_header(hdr, &size)) < 0)
status = error("unable to parse %s header", sha1_to_hex(sha1));
else if (sizep)
*sizep = size;
inflateEnd(&stream);
munmap(map, mapsize);
return status;
}
int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
{
struct pack_entry e;
if (!find_pack_entry(sha1, &e, NULL)) {
reprepare_packed_git();
if (!find_pack_entry(sha1, &e, NULL))
return sha1_loose_object_info(sha1, sizep);
}
return packed_object_info(e.p, e.offset, sizep);
}
static void *read_packed_sha1(const unsigned char *sha1,
enum object_type *type, unsigned long *size)
{
struct pack_entry e;
if (!find_pack_entry(sha1, &e, NULL))
return NULL;
else
return cache_or_unpack_entry(e.p, e.offset, size, type, 1);
}
/*
* This is meant to hold a *small* number of objects that you would
* want read_sha1_file() to be able to return, but yet you do not want
* to write them into the object store (e.g. a browse-only
* application).
*/
static struct cached_object {
unsigned char sha1[20];
enum object_type type;
void *buf;
unsigned long size;
} *cached_objects;
static int cached_object_nr, cached_object_alloc;
static struct cached_object *find_cached_object(const unsigned char *sha1)
{
int i;
struct cached_object *co = cached_objects;
for (i = 0; i < cached_object_nr; i++, co++) {
if (!hashcmp(co->sha1, sha1))
return co;
}
return NULL;
}
int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
unsigned char *sha1)
{
struct cached_object *co;
hash_sha1_file(buf, len, typename(type), sha1);
if (has_sha1_file(sha1) || find_cached_object(sha1))
return 0;
if (cached_object_alloc <= cached_object_nr) {
cached_object_alloc = alloc_nr(cached_object_alloc);
cached_objects = xrealloc(cached_objects,
sizeof(*cached_objects) *
cached_object_alloc);
}
co = &cached_objects[cached_object_nr++];
co->size = len;
co->type = type;
co->buf = xmalloc(len);
memcpy(co->buf, buf, len);
hashcpy(co->sha1, sha1);
return 0;
}
void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
unsigned long *size)
{
unsigned long mapsize;
void *map, *buf;
struct cached_object *co;
co = find_cached_object(sha1);
if (co) {
buf = xmalloc(co->size + 1);
memcpy(buf, co->buf, co->size);
((char*)buf)[co->size] = 0;
*type = co->type;
*size = co->size;
return buf;
}
buf = read_packed_sha1(sha1, type, size);
if (buf)
return buf;
map = map_sha1_file(sha1, &mapsize);
if (map) {
buf = unpack_sha1_file(map, mapsize, type, size, sha1);
munmap(map, mapsize);
return buf;
}
reprepare_packed_git();
return read_packed_sha1(sha1, type, size);
}
void *read_object_with_reference(const unsigned char *sha1,
const char *required_type_name,
unsigned long *size,
unsigned char *actual_sha1_return)
{
enum object_type type, required_type;
void *buffer;
unsigned long isize;
unsigned char actual_sha1[20];
required_type = type_from_string(required_type_name);
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 (type == required_type) {
*size = isize;
if (actual_sha1_return)
hashcpy(actual_sha1_return, actual_sha1);
return buffer;
}
/* Handle references */
else if (type == OBJ_COMMIT)
ref_type = "tree ";
else if (type == OBJ_TAG)
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(const void *buf, unsigned long len,
const char *type, unsigned char *sha1,
char *hdr, int *hdrlen)
{
SHA_CTX c;
/* Generate the header */
*hdrlen = sprintf(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;
if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
*dir = '/';
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) {
return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
}
/* FIXME!!! Collision check here ? */
}
return 0;
}
static int write_buffer(int fd, const void *buf, size_t len)
{
if (write_in_full(fd, buf, len) < 0)
return error("file write error (%s)", strerror(errno));
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, hdrlen;
if (use_legacy_headers) {
while (deflate(stream, 0) == Z_OK)
/* nothing */;
return;
}
obj_type = type_from_string(type);
hdrlen = write_binary_header(stream->next_out, obj_type, len);
stream->total_out = hdrlen;
stream->next_out += hdrlen;
stream->avail_out -= hdrlen;
}
int hash_sha1_file(const void *buf, unsigned long len, const char *type,
unsigned char *sha1)
{
char hdr[32];
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, ret;
unsigned char *compressed;
z_stream stream;
unsigned char sha1[20];
char *filename;
static char tmpfile[PATH_MAX];
char hdr[32];
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) {
return error("sha1 file %s: %s\n", filename, strerror(errno));
}
snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory());
fd = mkstemp(tmpfile);
if (fd < 0) {
if (errno == EPERM)
return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
else
return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
}
/* 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 = (unsigned char *)hdr;
stream.avail_in = hdrlen;
setup_object_header(&stream, type, len);
/* Then the data itself.. */
stream.next_in = buf;
stream.avail_in = len;
ret = deflate(&stream, Z_FINISH);
if (ret != Z_STREAM_END)
die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
ret = deflateEnd(&stream);
if (ret != Z_OK)
die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
size = stream.total_out;
if (write_buffer(fd, compressed, size) < 0)
die("unable to write sha1 file");
fchmod(fd, 0444);
if (close(fd))
die("unable to write sha1 file");
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;
enum object_type type;
char hdr[32];
int hdrlen;
void *buf;
/* need to unpack and recompress it by itself */
unpacked = read_packed_sha1(sha1, &type, &len);
if (!unpacked)
error("cannot read sha1_file for %s", sha1_to_hex(sha1));
hdrlen = sprintf(hdr, "%s %lu", typename(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/tmp_obj_XXXXXX", get_object_directory());
local = mkstemp(tmpfile);
if (local < 0) {
if (errno == EPERM)
return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
else
return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
}
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 = xread(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);
fchmod(local, 0444);
if (close(local) != 0)
die("unable to write sha1 file");
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,
enum object_type type, const char *path)
{
size_t size = xsize_t(st->st_size);
void *buf = NULL;
int ret, re_allocated = 0;
if (size)
buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (!type)
type = OBJ_BLOB;
/*
* Convert blobs to git internal format
*/
if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
unsigned long nsize = size;
char *nbuf = buf;
if (convert_to_git(path, &nbuf, &nsize)) {
if (size)
munmap(buf, size);
size = nsize;
buf = nbuf;
re_allocated = 1;
}
}
if (write_object)
ret = write_sha1_file(buf, size, typename(type), sha1);
else
ret = hash_sha1_file(buf, size, typename(type), sha1);
if (re_allocated) {
free(buf);
return ret;
}
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;
size_t len;
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, OBJ_BLOB, path) < 0)
return error("%s: failed to insert into database",
path);
break;
case S_IFLNK:
len = xsize_t(st->st_size);
target = xmalloc(len + 1);
if (readlink(path, target, len + 1) != st->st_size) {
char *errstr = strerror(errno);
free(target);
return error("readlink(\"%s\"): %s", path,
errstr);
}
if (!write_object)
hash_sha1_file(target, len, blob_type, sha1);
else if (write_sha1_file(target, len, blob_type, sha1))
return error("%s: failed to insert into database",
path);
free(target);
break;
case S_IFDIR:
return resolve_gitlink_ref(path, "HEAD", sha1);
default:
return error("%s: unsupported file type", path);
}
return 0;
}
int read_pack_header(int fd, struct pack_header *header)
{
char *c = (char*)header;
ssize_t remaining = sizeof(struct pack_header);
do {
ssize_t r = xread(fd, c, remaining);
if (r <= 0)
/* "eof before pack header was fully read" */
return PH_ERROR_EOF;
remaining -= r;
c += r;
} while (remaining > 0);
if (header->hdr_signature != htonl(PACK_SIGNATURE))
/* "protocol error (pack signature mismatch detected)" */
return PH_ERROR_PACK_SIGNATURE;
if (!pack_version_ok(header->hdr_version))
/* "protocol error (pack version unsupported)" */
return PH_ERROR_PROTOCOL;
return 0;
}
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