You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
359 lines
8.5 KiB
359 lines
8.5 KiB
#include <time.h> |
|
#include "cache.h" |
|
|
|
#define RECORDSIZE (512) |
|
#define BLOCKSIZE (RECORDSIZE * 20) |
|
|
|
static const char *tar_tree_usage = "tar-tree <key> [basedir]"; |
|
|
|
static char block[BLOCKSIZE]; |
|
static unsigned long offset; |
|
|
|
static const char *basedir; |
|
static time_t archive_time; |
|
|
|
struct path_prefix { |
|
struct path_prefix *prev; |
|
const char *name; |
|
}; |
|
|
|
/* tries hard to write, either succeeds or dies in the attempt */ |
|
static void reliable_write(void *buf, unsigned long size) |
|
{ |
|
while (size > 0) { |
|
long ret = write(1, buf, size); |
|
if (ret < 0) { |
|
if (errno == EAGAIN) |
|
continue; |
|
if (errno == EPIPE) |
|
exit(0); |
|
die("tar-tree: %s", strerror(errno)); |
|
} else if (!ret) { |
|
die("tar-tree: disk full?"); |
|
} |
|
size -= ret; |
|
buf += ret; |
|
} |
|
} |
|
|
|
/* writes out the whole block, but only if it is full */ |
|
static void write_if_needed(void) |
|
{ |
|
if (offset == BLOCKSIZE) { |
|
reliable_write(block, BLOCKSIZE); |
|
offset = 0; |
|
} |
|
} |
|
|
|
/* |
|
* The end of tar archives is marked by 1024 nul bytes and after that |
|
* follows the rest of the block (if any). |
|
*/ |
|
static void write_trailer(void) |
|
{ |
|
memset(block + offset, 0, RECORDSIZE); |
|
offset += RECORDSIZE; |
|
write_if_needed(); |
|
memset(block + offset, 0, RECORDSIZE); |
|
offset += RECORDSIZE; |
|
write_if_needed(); |
|
if (offset) { |
|
memset(block + offset, 0, BLOCKSIZE - offset); |
|
reliable_write(block, BLOCKSIZE); |
|
offset = 0; |
|
} |
|
} |
|
|
|
/* |
|
* queues up writes, so that all our write(2) calls write exactly one |
|
* full block; pads writes to RECORDSIZE |
|
*/ |
|
static void write_blocked(void *buf, unsigned long size) |
|
{ |
|
unsigned long tail; |
|
|
|
if (offset) { |
|
unsigned long chunk = BLOCKSIZE - offset; |
|
if (size < chunk) |
|
chunk = size; |
|
memcpy(block + offset, buf, chunk); |
|
size -= chunk; |
|
offset += chunk; |
|
buf += chunk; |
|
write_if_needed(); |
|
} |
|
while (size >= BLOCKSIZE) { |
|
reliable_write(buf, BLOCKSIZE); |
|
size -= BLOCKSIZE; |
|
buf += BLOCKSIZE; |
|
} |
|
if (size) { |
|
memcpy(block + offset, buf, size); |
|
buf += size; |
|
offset += size; |
|
} |
|
tail = offset % RECORDSIZE; |
|
if (tail) { |
|
memset(block + offset, 0, RECORDSIZE - tail); |
|
offset += RECORDSIZE - tail; |
|
} |
|
write_if_needed(); |
|
} |
|
|
|
static void append_string(char **p, const char *s) |
|
{ |
|
unsigned int len = strlen(s); |
|
memcpy(*p, s, len); |
|
*p += len; |
|
} |
|
|
|
static void append_char(char **p, char c) |
|
{ |
|
**p = c; |
|
*p += 1; |
|
} |
|
|
|
static void append_long(char **p, long n) |
|
{ |
|
int len = sprintf(*p, "%ld", n); |
|
*p += len; |
|
} |
|
|
|
static void append_path_prefix(char **buffer, struct path_prefix *prefix) |
|
{ |
|
if (!prefix) |
|
return; |
|
append_path_prefix(buffer, prefix->prev); |
|
append_string(buffer, prefix->name); |
|
append_char(buffer, '/'); |
|
} |
|
|
|
static unsigned int path_prefix_len(struct path_prefix *prefix) |
|
{ |
|
if (!prefix) |
|
return 0; |
|
return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1; |
|
} |
|
|
|
static void append_path(char **p, int is_dir, const char *basepath, |
|
struct path_prefix *prefix, const char *path) |
|
{ |
|
if (basepath) { |
|
append_string(p, basepath); |
|
append_char(p, '/'); |
|
} |
|
append_path_prefix(p, prefix); |
|
append_string(p, path); |
|
if (is_dir) |
|
append_char(p, '/'); |
|
} |
|
|
|
static unsigned int path_len(int is_dir, const char *basepath, |
|
struct path_prefix *prefix, const char *path) |
|
{ |
|
unsigned int len = 0; |
|
if (basepath) |
|
len += strlen(basepath) + 1; |
|
len += path_prefix_len(prefix) + strlen(path); |
|
if (is_dir) |
|
len++; |
|
return len; |
|
} |
|
|
|
static void write_header(const char *, const char *, struct path_prefix *, |
|
const char *, unsigned int, unsigned long); |
|
|
|
/* stores a pax extended header directly in the block buffer */ |
|
static void write_extended_header(const char *headerfilename, int is_dir, |
|
const char *basepath, |
|
struct path_prefix *prefix, |
|
const char *path, unsigned int namelen) |
|
{ |
|
char *records, *p; |
|
unsigned int size = 1 + 6 + namelen + 1; |
|
if (size > 9) |
|
size++; |
|
if (size > 99) |
|
size++; |
|
if (size > RECORDSIZE) |
|
die("tar-tree: extended header too big, wtf?"); |
|
write_header(NULL, NULL, NULL, headerfilename, 0100600, size); |
|
|
|
records = block + offset; |
|
memset(records, 0, RECORDSIZE); |
|
offset += RECORDSIZE; |
|
p = records; |
|
append_long(&p, size); |
|
append_string(&p, " path="); |
|
append_path(&p, is_dir, basepath, prefix, path); |
|
append_char(&p, '\n'); |
|
write_if_needed(); |
|
} |
|
|
|
/* stores a ustar header directly in the block buffer */ |
|
static void write_header(const char *sha1, const char *basepath, |
|
struct path_prefix *prefix, const char *path, |
|
unsigned int mode, unsigned long size) |
|
{ |
|
unsigned int namelen; |
|
char *p, *header = NULL; |
|
unsigned int checksum = 0; |
|
int i; |
|
|
|
namelen = path_len(S_ISDIR(mode), basepath, prefix, path); |
|
if (namelen > 500) { |
|
die("tar-tree: name too log of object %s\n", sha1_to_hex(sha1)); |
|
} else if (namelen > 100) { |
|
char *sha1_hex = sha1_to_hex(sha1); |
|
char headerfilename[51]; |
|
sprintf(headerfilename, "%s.paxheader", sha1_hex); |
|
/* the extended header must be written before the normal one */ |
|
write_extended_header(headerfilename, S_ISDIR(mode), basepath, |
|
prefix, path, namelen); |
|
|
|
header = block + offset; |
|
memset(header, 0, RECORDSIZE); |
|
offset += RECORDSIZE; |
|
sprintf(header, "%s.data", sha1_hex); |
|
} else { |
|
header = block + offset; |
|
memset(header, 0, RECORDSIZE); |
|
offset += RECORDSIZE; |
|
p = header; |
|
append_path(&p, S_ISDIR(mode), basepath, prefix, path); |
|
} |
|
|
|
if (S_ISDIR(mode)) |
|
mode |= 0755; /* GIT doesn't store permissions of dirs */ |
|
sprintf(&header[100], "%07o", mode & 07777); |
|
|
|
/* XXX: should we provide more meaningful info here? */ |
|
sprintf(&header[108], "%07o", 0); /* uid */ |
|
sprintf(&header[116], "%07o", 0); /* gid */ |
|
strncpy(&header[265], "git", 31); /* uname */ |
|
strncpy(&header[297], "git", 31); /* gname */ |
|
|
|
sprintf(&header[124], "%011lo", S_ISDIR(mode) ? 0 : size); |
|
sprintf(&header[136], "%011lo", archive_time); |
|
|
|
/* typeflag */ |
|
if (!sha1) |
|
header[156] = 'x'; /* extended header */ |
|
else |
|
header[156] = S_ISDIR(mode) ? '5' : '0'; |
|
|
|
memcpy(&header[257], "ustar", 6); |
|
memcpy(&header[263], "00", 2); |
|
|
|
printf(&header[329], "%07o", 0); /* devmajor */ |
|
printf(&header[337], "%07o", 0); /* devminor */ |
|
|
|
memset(&header[148], ' ', 8); |
|
for (i = 0; i < RECORDSIZE; i++) |
|
checksum += header[i]; |
|
sprintf(&header[148], "%07o", checksum & 0x1fffff); |
|
|
|
write_if_needed(); |
|
} |
|
|
|
static void traverse_tree(void *buffer, unsigned long size, |
|
struct path_prefix *prefix) |
|
{ |
|
struct path_prefix this_prefix; |
|
this_prefix.prev = prefix; |
|
|
|
while (size) { |
|
int namelen = strlen(buffer)+1; |
|
void *eltbuf; |
|
char elttype[20]; |
|
unsigned long eltsize; |
|
unsigned char *sha1 = buffer + namelen; |
|
char *path = strchr(buffer, ' ') + 1; |
|
unsigned int mode; |
|
|
|
if (size < namelen + 20 || sscanf(buffer, "%o", &mode) != 1) |
|
die("corrupt 'tree' file"); |
|
buffer = sha1 + 20; |
|
size -= namelen + 20; |
|
|
|
eltbuf = read_sha1_file(sha1, elttype, &eltsize); |
|
if (!eltbuf) |
|
die("cannot read %s", sha1_to_hex(sha1)); |
|
write_header(sha1, basedir, prefix, path, mode, eltsize); |
|
if (!strcmp(elttype, "tree")) { |
|
this_prefix.name = path; |
|
traverse_tree(eltbuf, eltsize, &this_prefix); |
|
} else if (!strcmp(elttype, "blob")) { |
|
write_blocked(eltbuf, eltsize); |
|
} |
|
free(eltbuf); |
|
} |
|
} |
|
|
|
/* get commit time from committer line of commit object */ |
|
time_t commit_time(void * buffer, unsigned long size) |
|
{ |
|
time_t result = 0; |
|
char *p = buffer; |
|
|
|
while (size > 0) { |
|
char *endp = memchr(p, '\n', size); |
|
if (!endp || endp == p) |
|
break; |
|
*endp = '\0'; |
|
if (endp - p > 10 && !memcmp(p, "committer ", 10)) { |
|
char *nump = strrchr(p, '>'); |
|
if (!nump) |
|
break; |
|
nump++; |
|
result = strtoul(nump, &endp, 10); |
|
if (*endp != ' ') |
|
result = 0; |
|
break; |
|
} |
|
size -= endp - p - 1; |
|
p = endp + 1; |
|
} |
|
return result; |
|
} |
|
|
|
int main(int argc, char **argv) |
|
{ |
|
unsigned char sha1[20]; |
|
void *buffer; |
|
unsigned long size; |
|
|
|
switch (argc) { |
|
case 3: |
|
basedir = argv[2]; |
|
/* FALLTHROUGH */ |
|
case 2: |
|
if (get_sha1_hex(argv[1], sha1) < 0) |
|
usage(tar_tree_usage); |
|
break; |
|
default: |
|
usage(tar_tree_usage); |
|
} |
|
|
|
sha1_file_directory = getenv(DB_ENVIRONMENT); |
|
if (!sha1_file_directory) |
|
sha1_file_directory = DEFAULT_DB_ENVIRONMENT; |
|
|
|
buffer = read_object_with_reference(sha1, "commit", &size, NULL); |
|
if (buffer) { |
|
archive_time = commit_time(buffer, size); |
|
free(buffer); |
|
} |
|
buffer = read_object_with_reference(sha1, "tree", &size, NULL); |
|
if (!buffer) |
|
die("not a reference to a tag, commit or tree object: %s", |
|
sha1_to_hex(sha1)); |
|
if (!archive_time) |
|
archive_time = time(NULL); |
|
if (basedir) |
|
write_header("0", NULL, NULL, basedir, 040755, 0); |
|
traverse_tree(buffer, size, NULL); |
|
free(buffer); |
|
write_trailer(); |
|
return 0; |
|
}
|
|
|