172 changes: 172 additions & 0 deletions commit-tree.c
@@ -0,0 +1,172 @@
#include "cache.h"

#include <pwd.h>
#include <time.h>

#define BLOCKING (1ul << 14)
#define ORIG_OFFSET (40)

/*
* Leave space at the beginning to insert the tag
* once we know how big things are.
*
* FIXME! Share the code with "write-tree.c"
*/
static void init_buffer(char **bufp, unsigned int *sizep)
{
char *buf = malloc(BLOCKING);
memset(buf, 0, ORIG_OFFSET);
*sizep = ORIG_OFFSET;
*bufp = buf;
}

static void add_buffer(char **bufp, unsigned int *sizep, const char *fmt, ...)
{
char one_line[2048];
va_list args;
int len;
unsigned long alloc, size, newsize;
char *buf;

va_start(args, fmt);
len = vsnprintf(one_line, sizeof(one_line), fmt, args);
va_end(args);
size = *sizep;
newsize = size + len;
alloc = (size + 32767) & ~32767;
buf = *bufp;
if (newsize > alloc) {
alloc = (newsize + 32767) & ~32767;
buf = realloc(buf, alloc);
*bufp = buf;
}
*sizep = newsize;
memcpy(buf + size, one_line, len);
}

static int prepend_integer(char *buffer, unsigned val, int i)
{
buffer[--i] = '\0';
do {
buffer[--i] = '0' + (val % 10);
val /= 10;
} while (val);
return i;
}

static void finish_buffer(char *tag, char **bufp, unsigned int *sizep)
{
int taglen;
int offset;
char *buf = *bufp;
unsigned int size = *sizep;

offset = prepend_integer(buf, size - ORIG_OFFSET, ORIG_OFFSET);
taglen = strlen(tag);
offset -= taglen;
buf += offset;
size -= offset;
memcpy(buf, tag, taglen);

*bufp = buf;
*sizep = size;
}

static void remove_special(char *p)
{
char c;
char *dst = p;

for (;;) {
c = *p;
p++;
switch(c) {
case '\n': case '<': case '>':
continue;
}
*dst++ = c;
if (!c)
break;
}
}

/*
* Having more than two parents may be strange, but hey, there's
* no conceptual reason why the file format couldn't accept multi-way
* merges. It might be the "union" of several packages, for example.
*
* I don't really expect that to happen, but this is here to make
* it clear that _conceptually_ it's ok..
*/

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@hello-smile6

hello-smile6 Mar 1, 2022

What does this mean?

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@EasyLover27

EasyLover27 Nov 3, 2022

This is an enclosing bracket for a multi-line comment:

https://www.w3schools.com/java/java_comments.asp#:~:text=Java%20Multi%2Dline%20Comments,will%20be%20ignored%20by%20Java.

You're welcome!
#define MAXPARENT (16)

int main(int argc, char **argv)
{
int i, len;
int parents = 0;
unsigned char tree_sha1[20];
unsigned char parent_sha1[MAXPARENT][20];
char *gecos, *realgecos;
char *email, realemail[1000];
char *date, *realdate;
char comment[1000];
struct passwd *pw;
time_t now;
char *buffer;
unsigned int size;

if (argc < 2 || get_sha1_hex(argv[1], tree_sha1) < 0)
usage("commit-tree <sha1> [-p <sha1>]* < changelog");

for (i = 2; i < argc; i += 2) {
char *a, *b;
a = argv[i]; b = argv[i+1];
if (!b || strcmp(a, "-p") || get_sha1_hex(b, parent_sha1[parents]))
usage("commit-tree <sha1> [-p <sha1>]* < changelog");
parents++;
}
if (!parents)
fprintf(stderr, "Committing initial tree %s\n", argv[1]);
pw = getpwuid(getuid());
if (!pw)
usage("You don't exist. Go away!");
realgecos = pw->pw_gecos;
len = strlen(pw->pw_name);
memcpy(realemail, pw->pw_name, len);
realemail[len] = '@';
gethostname(realemail+len+1, sizeof(realemail)-len-1);
time(&now);
realdate = ctime(&now);

gecos = getenv("COMMITTER_NAME") ? : realgecos;
email = getenv("COMMITTER_EMAIL") ? : realemail;
date = getenv("COMMITTER_DATE") ? : realdate;

remove_special(gecos); remove_special(realgecos);
remove_special(email); remove_special(realemail);
remove_special(date); remove_special(realdate);

init_buffer(&buffer, &size);
add_buffer(&buffer, &size, "tree %s\n", sha1_to_hex(tree_sha1));

/*
* NOTE! This ordering means that the same exact tree merged with a
* different order of parents will be a _different_ changeset even
* if everything else stays the same.
*/
for (i = 0; i < parents; i++)
add_buffer(&buffer, &size, "parent %s\n", sha1_to_hex(parent_sha1[i]));

/* Person/date information */
add_buffer(&buffer, &size, "author %s <%s> %s\n", gecos, email, date);
add_buffer(&buffer, &size, "committer %s <%s> %s\n\n", realgecos, realemail, realdate);

/* And add the comment */
while (fgets(comment, sizeof(comment), stdin) != NULL)
add_buffer(&buffer, &size, "%s", comment);

finish_buffer("commit ", &buffer, &size);

write_sha1_file(buffer, size);
return 0;
}
51 changes: 51 additions & 0 deletions init-db.c
@@ -0,0 +1,51 @@
#include "cache.h"

int main(int argc, char **argv)
{
char *sha1_dir = getenv(DB_ENVIRONMENT), *path;
int len, i, fd;

if (mkdir(".dircache", 0700) < 0) {
perror("unable to create .dircache");
exit(1);
}

/*
* If you want to, you can share the DB area with any number of branches.
* That has advantages: you can save space by sharing all the SHA1 objects.
* On the other hand, it might just make lookup slower and messier. You
* be the judge.
*/
sha1_dir = getenv(DB_ENVIRONMENT);
if (sha1_dir) {
struct stat st;
if (!stat(sha1_dir, &st) < 0 && S_ISDIR(st.st_mode))
return;
fprintf(stderr, "DB_ENVIRONMENT set to bad directory %s: ", sha1_dir);
}

/*
* The default case is to have a DB per managed directory.
*/
sha1_dir = DEFAULT_DB_ENVIRONMENT;
fprintf(stderr, "defaulting to private storage area\n");
len = strlen(sha1_dir);
if (mkdir(sha1_dir, 0700) < 0) {
if (errno != EEXIST) {
perror(sha1_dir);
exit(1);
}
}
path = malloc(len + 40);
memcpy(path, sha1_dir, len);
for (i = 0; i < 256; i++) {
sprintf(path+len, "/%02x", i);
if (mkdir(path, 0700) < 0) {
if (errno != EEXIST) {
perror(path);
exit(1);
}
}
}
return 0;
}
259 changes: 259 additions & 0 deletions read-cache.c
@@ -0,0 +1,259 @@
#include "cache.h"

const char *sha1_file_directory = NULL;
struct cache_entry **active_cache = NULL;
unsigned int active_nr = 0, active_alloc = 0;

void usage(const char *err)
{
fprintf(stderr, "read-tree: %s\n", err);
exit(1);
}

static unsigned hexval(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return ~0;
}

int get_sha1_hex(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;
}

char * sha1_to_hex(unsigned char *sha1)
{
static char buffer[50];
static const char hex[] = "0123456789abcdef";
char *buf = buffer;
int i;

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

/*
* NOTE! This returns a statically allocated buffer, so you have to be
* careful about using it. Do a "strdup()" if you need to save the
* filename.
*/
char *sha1_file_name(unsigned char *sha1)
{
int i;
static char *name, *base;

if (!base) {
char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
int len = strlen(sha1_file_directory);
base = malloc(len + 60);
memcpy(base, sha1_file_directory, len);
memset(base+len, 0, 60);
base[len] = '/';
base[len+3] = '/';
name = base + len + 1;
}
for (i = 0; i < 20; i++) {
static char hex[] = "0123456789abcdef";
unsigned int val = sha1[i];
char *pos = name + i*2 + (i > 0);
*pos++ = hex[val >> 4];
*pos = hex[val & 0xf];
}
return base;
}

void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
{
z_stream stream;
char buffer[8192];
struct stat st;
int i, fd, ret, bytes;
void *map, *buf;
char *filename = sha1_file_name(sha1);

fd = open(filename, O_RDONLY);
if (fd < 0) {
perror(filename);
return NULL;
}
if (fstat(fd, &st) < 0) {
close(fd);
return NULL;
}
map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (-1 == (int)(long)map)
return NULL;

/* Get the data stream */
memset(&stream, 0, sizeof(stream));
stream.next_in = map;
stream.avail_in = st.st_size;
stream.next_out = buffer;
stream.avail_out = sizeof(buffer);

inflateInit(&stream);
ret = inflate(&stream, 0);
if (sscanf(buffer, "%10s %lu", type, size) != 2)
return NULL;
bytes = strlen(buffer) + 1;
buf = malloc(*size);
if (!buf)
return NULL;

memcpy(buf, buffer + bytes, stream.total_out - bytes);
bytes = stream.total_out - bytes;
if (bytes < *size && ret == Z_OK) {
stream.next_out = buf + bytes;
stream.avail_out = *size - bytes;
while (inflate(&stream, Z_FINISH) == Z_OK)
/* nothing */;
}
inflateEnd(&stream);
return buf;
}

int write_sha1_file(char *buf, unsigned len)
{
int size;
char *compressed;
z_stream stream;
unsigned char sha1[20];
SHA_CTX c;

/* Set it up */
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, Z_BEST_COMPRESSION);
size = deflateBound(&stream, len);
compressed = malloc(size);

/* Compress it */
stream.next_in = buf;
stream.avail_in = len;
stream.next_out = compressed;
stream.avail_out = size;
while (deflate(&stream, Z_FINISH) == Z_OK)
/* nothing */;
deflateEnd(&stream);
size = stream.total_out;

/* Sha1.. */
SHA1_Init(&c);
SHA1_Update(&c, compressed, size);
SHA1_Final(sha1, &c);

if (write_sha1_buffer(sha1, compressed, size) < 0)
return -1;
printf("%s\n", sha1_to_hex(sha1));
return 0;
}

int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
{
char *filename = sha1_file_name(sha1);
int i, fd;

fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
if (fd < 0)
return (errno == EEXIST) ? 0 : -1;
write(fd, buf, size);
close(fd);
return 0;
}

static int error(const char * string)
{
fprintf(stderr, "error: %s\n", string);
return -1;
}

static int verify_hdr(struct cache_header *hdr, unsigned long size)
{
SHA_CTX c;
unsigned char sha1[20];

if (hdr->signature != CACHE_SIGNATURE)
return error("bad signature");
if (hdr->version != 1)
return error("bad version");
SHA1_Init(&c);
SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
SHA1_Final(sha1, &c);
if (memcmp(sha1, hdr->sha1, 20))
return error("bad header sha1");
return 0;
}

int read_cache(void)
{
int fd, i;
struct stat st;
unsigned long size, offset;
void *map;
struct cache_header *hdr;

errno = EBUSY;
if (active_cache)
return error("more than one cachefile");
errno = ENOENT;
sha1_file_directory = getenv(DB_ENVIRONMENT);
if (!sha1_file_directory)
sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
if (access(sha1_file_directory, X_OK) < 0)
return error("no access to SHA1 file directory");
fd = open(".dircache/index", O_RDONLY);
if (fd < 0)
return (errno == ENOENT) ? 0 : error("open failed");

map = (void *)-1;
if (!fstat(fd, &st)) {
map = NULL;
size = st.st_size;
errno = EINVAL;
if (size > sizeof(struct cache_header))
map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
}
close(fd);
if (-1 == (int)(long)map)
return error("mmap failed");

hdr = map;
if (verify_hdr(hdr, size) < 0)
goto unmap;

active_nr = hdr->entries;
active_alloc = alloc_nr(active_nr);
active_cache = calloc(active_alloc, sizeof(struct cache_entry *));

offset = sizeof(*hdr);
for (i = 0; i < hdr->entries; i++) {
struct cache_entry *ce = map + offset;
offset = offset + ce_size(ce);
active_cache[i] = ce;
}
return active_nr;

unmap:
munmap(map, size);
errno = EINVAL;
return error("verify header failed");
}

43 changes: 43 additions & 0 deletions read-tree.c
@@ -0,0 +1,43 @@
#include "cache.h"

static int unpack(unsigned char *sha1)
{
void *buffer;
unsigned long size;
char type[20];

buffer = read_sha1_file(sha1, type, &size);
if (!buffer)
usage("unable to read sha1 file");
if (strcmp(type, "tree"))
usage("expected a 'tree' node");
while (size) {
int len = strlen(buffer)+1;
unsigned char *sha1 = buffer + len;
char *path = strchr(buffer, ' ')+1;
unsigned int mode;
if (size < len + 20 || sscanf(buffer, "%o", &mode) != 1)
usage("corrupt 'tree' file");
buffer = sha1 + 20;
size -= len + 20;
printf("%o %s (%s)\n", mode, path, sha1_to_hex(sha1));
}
return 0;
}

int main(int argc, char **argv)
{
int fd;
unsigned char sha1[20];

if (argc != 2)
usage("read-tree <key>");
if (get_sha1_hex(argv[1], sha1) < 0)
usage("read-tree <key>");
sha1_file_directory = getenv(DB_ENVIRONMENT);
if (!sha1_file_directory)
sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
if (unpack(sha1) < 0)
usage("unpack failed");
return 0;
}
81 changes: 81 additions & 0 deletions show-diff.c
@@ -0,0 +1,81 @@
#include "cache.h"

#define MTIME_CHANGED 0x0001
#define CTIME_CHANGED 0x0002
#define OWNER_CHANGED 0x0004
#define MODE_CHANGED 0x0008
#define INODE_CHANGED 0x0010
#define DATA_CHANGED 0x0020

static int match_stat(struct cache_entry *ce, struct stat *st)
{
unsigned int changed = 0;

if (ce->mtime.sec != (unsigned int)st->st_mtim.tv_sec ||
ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec)
changed |= MTIME_CHANGED;
if (ce->ctime.sec != (unsigned int)st->st_ctim.tv_sec ||
ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec)
changed |= CTIME_CHANGED;
if (ce->st_uid != (unsigned int)st->st_uid ||
ce->st_gid != (unsigned int)st->st_gid)
changed |= OWNER_CHANGED;
if (ce->st_mode != (unsigned int)st->st_mode)
changed |= MODE_CHANGED;
if (ce->st_dev != (unsigned int)st->st_dev ||
ce->st_ino != (unsigned int)st->st_ino)
changed |= INODE_CHANGED;
if (ce->st_size != (unsigned int)st->st_size)
changed |= DATA_CHANGED;
return changed;
}

static void show_differences(struct cache_entry *ce, struct stat *cur,
void *old_contents, unsigned long long old_size)
{
static char cmd[1000];
FILE *f;

snprintf(cmd, sizeof(cmd), "diff -u - %s", ce->name);
f = popen(cmd, "w");
fwrite(old_contents, old_size, 1, f);
pclose(f);
}

int main(int argc, char **argv)
{
int entries = read_cache();
int i;

if (entries < 0) {
perror("read_cache");
exit(1);
}
for (i = 0; i < entries; i++) {
struct stat st;
struct cache_entry *ce = active_cache[i];
int n, changed;
unsigned int mode;
unsigned long size;
char type[20];
void *new;

if (stat(ce->name, &st) < 0) {
printf("%s: %s\n", ce->name, strerror(errno));
continue;
}
changed = match_stat(ce, &st);
if (!changed) {
printf("%s: ok\n", ce->name);
continue;
}
printf("%.*s: ", ce->namelen, ce->name);
for (n = 0; n < 20; n++)
printf("%02x", ce->sha1[n]);
printf("\n");
new = read_sha1_file(ce->sha1, type, &size);
show_differences(ce, &st, new, size);
free(new);
}
return 0;
}
248 changes: 248 additions & 0 deletions update-cache.c
@@ -0,0 +1,248 @@
#include "cache.h"

static int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
{
int len = len1 < len2 ? len1 : len2;
int cmp;

cmp = memcmp(name1, name2, len);
if (cmp)
return cmp;
if (len1 < len2)
return -1;
if (len1 > len2)
return 1;
return 0;
}

static int cache_name_pos(const char *name, int namelen)
{
int first, last;

first = 0;
last = active_nr;
while (last > first) {
int next = (last + first) >> 1;
struct cache_entry *ce = active_cache[next];
int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
if (!cmp)
return -next-1;
if (cmp < 0) {
last = next;
continue;
}
first = next+1;
}
return first;
}

static int remove_file_from_cache(char *path)
{
int pos = cache_name_pos(path, strlen(path));
if (pos < 0) {
pos = -pos-1;
active_nr--;
if (pos < active_nr)
memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
}
}

static int add_cache_entry(struct cache_entry *ce)
{
int pos;

pos = cache_name_pos(ce->name, ce->namelen);

/* existing match? Just replace it */
if (pos < 0) {
active_cache[-pos-1] = ce;
return 0;
}

/* Make sure the array is big enough .. */
if (active_nr == active_alloc) {
active_alloc = alloc_nr(active_alloc);
active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
}

/* Add it in.. */
active_nr++;
if (active_nr > pos)
memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
active_cache[pos] = ce;
return 0;
}

static int index_fd(const char *path, int namelen, struct cache_entry *ce, int fd, struct stat *st)
{
z_stream stream;
int max_out_bytes = namelen + st->st_size + 200;
void *out = malloc(max_out_bytes);
void *metadata = malloc(namelen + 200);
void *in = mmap(NULL, st->st_size, PROT_READ, MAP_PRIVATE, fd, 0);
SHA_CTX c;

close(fd);
if (!out || (int)(long)in == -1)
return -1;

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

/*
* ASCII size + nul byte
*/
stream.next_in = metadata;
stream.avail_in = 1+sprintf(metadata, "blob %lu", (unsigned long) st->st_size);
stream.next_out = out;
stream.avail_out = max_out_bytes;
while (deflate(&stream, 0) == Z_OK)
/* nothing */;

/*
* File content
*/
stream.next_in = in;
stream.avail_in = st->st_size;
while (deflate(&stream, Z_FINISH) == Z_OK)
/*nothing */;

deflateEnd(&stream);

SHA1_Init(&c);
SHA1_Update(&c, out, stream.total_out);
SHA1_Final(ce->sha1, &c);

return write_sha1_buffer(ce->sha1, out, stream.total_out);
}

static int add_file_to_cache(char *path)
{
int size, namelen;
struct cache_entry *ce;
struct stat st;
int fd;

fd = open(path, O_RDONLY);
if (fd < 0) {
if (errno == ENOENT)
return remove_file_from_cache(path);
return -1;
}
if (fstat(fd, &st) < 0) {
close(fd);
return -1;
}
namelen = strlen(path);
size = cache_entry_size(namelen);
ce = malloc(size);
memset(ce, 0, size);
memcpy(ce->name, path, namelen);
ce->ctime.sec = st.st_ctime;
ce->ctime.nsec = st.st_ctim.tv_nsec;
ce->mtime.sec = st.st_mtime;
ce->mtime.nsec = st.st_mtim.tv_nsec;
ce->st_dev = st.st_dev;
ce->st_ino = st.st_ino;
ce->st_mode = st.st_mode;
ce->st_uid = st.st_uid;
ce->st_gid = st.st_gid;
ce->st_size = st.st_size;
ce->namelen = namelen;

if (index_fd(path, namelen, ce, fd, &st) < 0)
return -1;

return add_cache_entry(ce);
}

static int write_cache(int newfd, struct cache_entry **cache, int entries)
{
SHA_CTX c;
struct cache_header hdr;
int i;

hdr.signature = CACHE_SIGNATURE;
hdr.version = 1;
hdr.entries = entries;

SHA1_Init(&c);
SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
int size = ce_size(ce);
SHA1_Update(&c, ce, size);
}
SHA1_Final(hdr.sha1, &c);

if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
return -1;

for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
int size = ce_size(ce);
if (write(newfd, ce, size) != size)
return -1;
}
return 0;
}

/*
* We fundamentally don't like some paths: we don't want
* dot or dot-dot anywhere, and in fact, we don't even want
* any other dot-files (.dircache or anything else). They
* are hidden, for chist sake.
*
* Also, we don't want double slashes or slashes at the
* end that can make pathnames ambiguous.
*/
static int verify_path(char *path)
{
char c;

goto inside;
for (;;) {
if (!c)
return 1;
if (c == '/') {
inside:
c = *path++;
if (c != '/' && c != '.' && c != '\0')
continue;
return 0;
}
c = *path++;
}
}

int main(int argc, char **argv)
{
int i, newfd, entries;

entries = read_cache();
if (entries < 0) {
perror("cache corrupted");
return -1;
}

newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
if (newfd < 0) {
perror("unable to create new cachefile");
return -1;
}
for (i = 1 ; i < argc; i++) {
char *path = argv[i];
if (!verify_path(path)) {
fprintf(stderr, "Ignoring path %s\n", argv[i]);
continue;
}
if (add_file_to_cache(path)) {
fprintf(stderr, "Unable to add %s to database\n", path);
goto out;
}
}
if (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
return 0;
out:
unlink(".dircache/index.lock");
}
66 changes: 66 additions & 0 deletions write-tree.c
@@ -0,0 +1,66 @@
#include "cache.h"

static int check_valid_sha1(unsigned char *sha1)
{
char *filename = sha1_file_name(sha1);
int ret;

/* If we were anal, we'd check that the sha1 of the contents actually matches */
ret = access(filename, R_OK);
if (ret)
perror(filename);
return ret;
}

static int prepend_integer(char *buffer, unsigned val, int i)
{
buffer[--i] = '\0';
do {
buffer[--i] = '0' + (val % 10);
val /= 10;
} while (val);
return i;
}

#define ORIG_OFFSET (40) /* Enough space to add the header of "tree <size>\0" */

int main(int argc, char **argv)
{
unsigned long size, offset, val;
int i, entries = read_cache();
char *buffer;

if (entries <= 0) {
fprintf(stderr, "No file-cache to create a tree of\n");
exit(1);
}

/* Guess at an initial size */
size = entries * 40 + 400;
buffer = malloc(size);
offset = ORIG_OFFSET;

for (i = 0; i < entries; i++) {
struct cache_entry *ce = active_cache[i];
if (check_valid_sha1(ce->sha1) < 0)
exit(1);
if (offset + ce->namelen + 60 > size) {
size = alloc_nr(offset + ce->namelen + 60);
buffer = realloc(buffer, size);
}
offset += sprintf(buffer + offset, "%o %s", ce->st_mode, ce->name);
buffer[offset++] = 0;
memcpy(buffer + offset, ce->sha1, 20);
offset += 20;
}

i = prepend_integer(buffer, offset - ORIG_OFFSET, ORIG_OFFSET);
i -= 5;
memcpy(buffer+i, "tree ", 5);

buffer += i;
offset -= i;

write_sha1_file(buffer, offset);
return 0;
}