351 lines
8.4 KiB
C
351 lines
8.4 KiB
C
/*
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* Copyright (c) 2005, 2006 Rene Scharfe
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*/
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#include <time.h>
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#include "cache.h"
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#include "tree-walk.h"
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#include "commit.h"
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#include "strbuf.h"
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#include "tar.h"
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#define RECORDSIZE (512)
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#define BLOCKSIZE (RECORDSIZE * 20)
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static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";
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static char block[BLOCKSIZE];
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static unsigned long offset;
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static time_t archive_time;
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/* tries hard to write, either succeeds or dies in the attempt */
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static void reliable_write(void *buf, unsigned long size)
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{
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while (size > 0) {
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long ret = xwrite(1, buf, size);
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if (ret < 0) {
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if (errno == EPIPE)
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exit(0);
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die("git-tar-tree: %s", strerror(errno));
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} else if (!ret) {
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die("git-tar-tree: disk full?");
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}
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size -= ret;
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buf += ret;
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}
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}
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/* writes out the whole block, but only if it is full */
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static void write_if_needed(void)
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{
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if (offset == BLOCKSIZE) {
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reliable_write(block, BLOCKSIZE);
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offset = 0;
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}
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}
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/* acquire the next record from the buffer; user must call write_if_needed() */
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static char *get_record(void)
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{
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char *p = block + offset;
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memset(p, 0, RECORDSIZE);
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offset += RECORDSIZE;
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return p;
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}
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/*
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* The end of tar archives is marked by 1024 nul bytes and after that
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* follows the rest of the block (if any).
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*/
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static void write_trailer(void)
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{
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get_record();
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write_if_needed();
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get_record();
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write_if_needed();
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while (offset) {
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get_record();
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write_if_needed();
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}
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}
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/*
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* queues up writes, so that all our write(2) calls write exactly one
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* full block; pads writes to RECORDSIZE
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*/
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static void write_blocked(void *buf, unsigned long size)
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{
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unsigned long tail;
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if (offset) {
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unsigned long chunk = BLOCKSIZE - offset;
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if (size < chunk)
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chunk = size;
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memcpy(block + offset, buf, chunk);
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size -= chunk;
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offset += chunk;
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buf += chunk;
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write_if_needed();
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}
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while (size >= BLOCKSIZE) {
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reliable_write(buf, BLOCKSIZE);
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size -= BLOCKSIZE;
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buf += BLOCKSIZE;
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}
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if (size) {
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memcpy(block + offset, buf, size);
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offset += size;
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}
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tail = offset % RECORDSIZE;
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if (tail) {
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memset(block + offset, 0, RECORDSIZE - tail);
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offset += RECORDSIZE - tail;
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}
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write_if_needed();
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}
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static void strbuf_append_string(struct strbuf *sb, const char *s)
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{
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int slen = strlen(s);
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int total = sb->len + slen;
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if (total > sb->alloc) {
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sb->buf = xrealloc(sb->buf, total);
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sb->alloc = total;
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}
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memcpy(sb->buf + sb->len, s, slen);
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sb->len = total;
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}
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/*
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* pax extended header records have the format "%u %s=%s\n". %u contains
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* the size of the whole string (including the %u), the first %s is the
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* keyword, the second one is the value. This function constructs such a
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* string and appends it to a struct strbuf.
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*/
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static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
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const char *value, unsigned int valuelen)
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{
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char *p;
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int len, total, tmp;
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/* "%u %s=%s\n" */
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len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
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for (tmp = len; tmp > 9; tmp /= 10)
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len++;
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total = sb->len + len;
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if (total > sb->alloc) {
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sb->buf = xrealloc(sb->buf, total);
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sb->alloc = total;
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}
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p = sb->buf;
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p += sprintf(p, "%u %s=", len, keyword);
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memcpy(p, value, valuelen);
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p += valuelen;
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*p = '\n';
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sb->len = total;
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}
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static unsigned int ustar_header_chksum(const struct ustar_header *header)
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{
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char *p = (char *)header;
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unsigned int chksum = 0;
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while (p < header->chksum)
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chksum += *p++;
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chksum += sizeof(header->chksum) * ' ';
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p += sizeof(header->chksum);
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while (p < (char *)header + sizeof(struct ustar_header))
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chksum += *p++;
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return chksum;
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}
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static int get_path_prefix(const struct strbuf *path, int maxlen)
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{
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int i = path->len;
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if (i > maxlen)
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i = maxlen;
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while (i > 0 && path->buf[i] != '/')
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i--;
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return i;
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}
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static void write_entry(const unsigned char *sha1, struct strbuf *path,
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unsigned int mode, void *buffer, unsigned long size)
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{
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struct ustar_header header;
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struct strbuf ext_header;
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memset(&header, 0, sizeof(header));
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ext_header.buf = NULL;
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ext_header.len = ext_header.alloc = 0;
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if (!sha1) {
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*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
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mode = 0100666;
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strcpy(header.name, "pax_global_header");
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} else if (!path) {
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*header.typeflag = TYPEFLAG_EXT_HEADER;
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mode = 0100666;
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sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
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} else {
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if (S_ISDIR(mode)) {
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*header.typeflag = TYPEFLAG_DIR;
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mode |= 0777;
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} else if (S_ISLNK(mode)) {
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*header.typeflag = TYPEFLAG_LNK;
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mode |= 0777;
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} else if (S_ISREG(mode)) {
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*header.typeflag = TYPEFLAG_REG;
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mode |= (mode & 0100) ? 0777 : 0666;
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} else {
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error("unsupported file mode: 0%o (SHA1: %s)",
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mode, sha1_to_hex(sha1));
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return;
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}
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if (path->len > sizeof(header.name)) {
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int plen = get_path_prefix(path, sizeof(header.prefix));
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int rest = path->len - plen - 1;
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if (plen > 0 && rest <= sizeof(header.name)) {
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memcpy(header.prefix, path->buf, plen);
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memcpy(header.name, path->buf + plen + 1, rest);
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} else {
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sprintf(header.name, "%s.data",
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sha1_to_hex(sha1));
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strbuf_append_ext_header(&ext_header, "path",
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path->buf, path->len);
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}
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} else
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memcpy(header.name, path->buf, path->len);
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}
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if (S_ISLNK(mode) && buffer) {
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if (size > sizeof(header.linkname)) {
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sprintf(header.linkname, "see %s.paxheader",
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sha1_to_hex(sha1));
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strbuf_append_ext_header(&ext_header, "linkpath",
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buffer, size);
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} else
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memcpy(header.linkname, buffer, size);
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}
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sprintf(header.mode, "%07o", mode & 07777);
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sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
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sprintf(header.mtime, "%011lo", archive_time);
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/* XXX: should we provide more meaningful info here? */
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sprintf(header.uid, "%07o", 0);
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sprintf(header.gid, "%07o", 0);
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strncpy(header.uname, "git", 31);
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strncpy(header.gname, "git", 31);
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sprintf(header.devmajor, "%07o", 0);
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sprintf(header.devminor, "%07o", 0);
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memcpy(header.magic, "ustar", 6);
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memcpy(header.version, "00", 2);
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sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
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if (ext_header.len > 0) {
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write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
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free(ext_header.buf);
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}
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write_blocked(&header, sizeof(header));
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if (S_ISREG(mode) && buffer && size > 0)
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write_blocked(buffer, size);
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}
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static void write_global_extended_header(const unsigned char *sha1)
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{
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struct strbuf ext_header;
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ext_header.buf = NULL;
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ext_header.len = ext_header.alloc = 0;
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strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
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write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
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free(ext_header.buf);
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}
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static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
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{
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int pathlen = path->len;
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while (tree->size) {
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const char *name;
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const unsigned char *sha1;
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unsigned mode;
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void *eltbuf;
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char elttype[20];
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unsigned long eltsize;
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sha1 = tree_entry_extract(tree, &name, &mode);
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update_tree_entry(tree);
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eltbuf = read_sha1_file(sha1, elttype, &eltsize);
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if (!eltbuf)
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die("cannot read %s", sha1_to_hex(sha1));
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path->len = pathlen;
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strbuf_append_string(path, name);
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if (S_ISDIR(mode))
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strbuf_append_string(path, "/");
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write_entry(sha1, path, mode, eltbuf, eltsize);
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if (S_ISDIR(mode)) {
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struct tree_desc subtree;
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subtree.buf = eltbuf;
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subtree.size = eltsize;
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traverse_tree(&subtree, path);
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}
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free(eltbuf);
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}
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}
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int main(int argc, char **argv)
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{
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unsigned char sha1[20], tree_sha1[20];
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struct commit *commit;
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struct tree_desc tree;
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struct strbuf current_path;
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current_path.buf = xmalloc(PATH_MAX);
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current_path.alloc = PATH_MAX;
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current_path.len = current_path.eof = 0;
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setup_git_directory();
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git_config(git_default_config);
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switch (argc) {
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case 3:
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strbuf_append_string(¤t_path, argv[2]);
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strbuf_append_string(¤t_path, "/");
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/* FALLTHROUGH */
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case 2:
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if (get_sha1(argv[1], sha1) < 0)
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usage(tar_tree_usage);
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break;
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default:
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usage(tar_tree_usage);
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}
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commit = lookup_commit_reference_gently(sha1, 1);
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if (commit) {
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write_global_extended_header(commit->object.sha1);
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archive_time = commit->date;
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} else
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archive_time = time(NULL);
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tree.buf = read_object_with_reference(sha1, tree_type, &tree.size,
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tree_sha1);
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if (!tree.buf)
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die("not a reference to a tag, commit or tree object: %s",
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sha1_to_hex(sha1));
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if (current_path.len > 0)
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write_entry(tree_sha1, ¤t_path, 040777, NULL, 0);
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traverse_tree(&tree, ¤t_path);
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write_trailer();
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free(current_path.buf);
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return 0;
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}
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