зеркало из https://github.com/microsoft/git.git
412 строки
10 KiB
C
412 строки
10 KiB
C
/*
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* Copyright (c) 2005 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 "diff.h"
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#include "commit.h"
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#define RECORDSIZE (512)
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#define BLOCKSIZE (RECORDSIZE * 20)
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#define TYPEFLAG_AUTO '\0'
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#define TYPEFLAG_REG '0'
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#define TYPEFLAG_LNK '2'
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#define TYPEFLAG_DIR '5'
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#define TYPEFLAG_GLOBAL_HEADER 'g'
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#define TYPEFLAG_EXT_HEADER 'x'
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#define EXT_HEADER_PATH 1
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#define EXT_HEADER_LINKPATH 2
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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 const char *basedir;
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static time_t archive_time;
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struct path_prefix {
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struct path_prefix *prev;
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const char *name;
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};
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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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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 append_string(char **p, const char *s)
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{
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unsigned int len = strlen(s);
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memcpy(*p, s, len);
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*p += len;
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}
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static void append_char(char **p, char c)
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{
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**p = c;
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*p += 1;
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}
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static void append_path_prefix(char **buffer, struct path_prefix *prefix)
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{
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if (!prefix)
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return;
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append_path_prefix(buffer, prefix->prev);
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append_string(buffer, prefix->name);
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append_char(buffer, '/');
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}
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static unsigned int path_prefix_len(struct path_prefix *prefix)
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{
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if (!prefix)
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return 0;
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return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1;
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}
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static void append_path(char **p, int is_dir, const char *basepath,
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struct path_prefix *prefix, const char *path)
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{
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if (basepath) {
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append_string(p, basepath);
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append_char(p, '/');
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}
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append_path_prefix(p, prefix);
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append_string(p, path);
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if (is_dir)
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append_char(p, '/');
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}
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static unsigned int path_len(int is_dir, const char *basepath,
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struct path_prefix *prefix, const char *path)
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{
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unsigned int len = 0;
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if (basepath)
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len += strlen(basepath) + 1;
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len += path_prefix_len(prefix) + strlen(path);
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if (is_dir)
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len++;
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return len;
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}
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static void append_extended_header_prefix(char **p, unsigned int size,
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const char *keyword)
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{
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int len = sprintf(*p, "%u %s=", size, keyword);
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*p += len;
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}
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static unsigned int extended_header_len(const char *keyword,
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unsigned int valuelen)
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{
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/* "%u %s=%s\n" */
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unsigned int len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
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if (len > 9)
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len++;
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if (len > 99)
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len++;
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return len;
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}
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static void append_extended_header(char **p, const char *keyword,
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const char *value, unsigned int len)
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{
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unsigned int size = extended_header_len(keyword, len);
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append_extended_header_prefix(p, size, keyword);
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memcpy(*p, value, len);
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*p += len;
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append_char(p, '\n');
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}
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static void write_header(const unsigned char *, char, const char *, struct path_prefix *,
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const char *, unsigned int, void *, unsigned long);
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/* stores a pax extended header directly in the block buffer */
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static void write_extended_header(const char *headerfilename, int is_dir,
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unsigned int flags, const char *basepath,
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struct path_prefix *prefix,
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const char *path, unsigned int namelen,
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void *content, unsigned int contentsize)
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{
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char *buffer, *p;
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unsigned int pathlen, size, linkpathlen = 0;
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size = pathlen = extended_header_len("path", namelen);
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if (flags & EXT_HEADER_LINKPATH) {
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linkpathlen = extended_header_len("linkpath", contentsize);
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size += linkpathlen;
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}
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write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
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0100600, NULL, size);
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buffer = p = malloc(size);
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if (!buffer)
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die("git-tar-tree: %s", strerror(errno));
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append_extended_header_prefix(&p, pathlen, "path");
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append_path(&p, is_dir, basepath, prefix, path);
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append_char(&p, '\n');
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if (flags & EXT_HEADER_LINKPATH)
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append_extended_header(&p, "linkpath", content, contentsize);
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write_blocked(buffer, size);
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free(buffer);
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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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char *p;
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unsigned int size;
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size = extended_header_len("comment", 40);
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write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
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"pax_global_header", 0100600, NULL, size);
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p = get_record();
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append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
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write_if_needed();
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}
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/* stores a ustar header directly in the block buffer */
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static void write_header(const unsigned char *sha1, char typeflag, const char *basepath,
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struct path_prefix *prefix, const char *path,
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unsigned int mode, void *buffer, unsigned long size)
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{
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unsigned int namelen;
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char *header = NULL;
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unsigned int checksum = 0;
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int i;
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unsigned int ext_header = 0;
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if (typeflag == TYPEFLAG_AUTO) {
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if (S_ISDIR(mode))
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typeflag = TYPEFLAG_DIR;
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else if (S_ISLNK(mode))
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typeflag = TYPEFLAG_LNK;
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else
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typeflag = TYPEFLAG_REG;
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}
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namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
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if (namelen > 100)
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ext_header |= EXT_HEADER_PATH;
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if (typeflag == TYPEFLAG_LNK && size > 100)
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ext_header |= EXT_HEADER_LINKPATH;
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/* the extended header must be written before the normal one */
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if (ext_header) {
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char headerfilename[51];
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sprintf(headerfilename, "%s.paxheader", sha1_to_hex(sha1));
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write_extended_header(headerfilename, S_ISDIR(mode),
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ext_header, basepath, prefix, path,
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namelen, buffer, size);
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}
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header = get_record();
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if (ext_header) {
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sprintf(header, "%s.data", sha1_to_hex(sha1));
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} else {
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char *p = header;
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append_path(&p, S_ISDIR(mode), basepath, prefix, path);
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}
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if (typeflag == TYPEFLAG_LNK) {
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if (ext_header & EXT_HEADER_LINKPATH) {
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sprintf(&header[157], "see %s.paxheader",
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sha1_to_hex(sha1));
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} else {
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if (buffer)
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strncpy(&header[157], buffer, size);
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}
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}
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if (S_ISDIR(mode))
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mode |= 0755; /* GIT doesn't store permissions of dirs */
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if (S_ISLNK(mode))
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mode |= 0777; /* ... nor of symlinks */
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sprintf(&header[100], "%07o", mode & 07777);
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/* XXX: should we provide more meaningful info here? */
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sprintf(&header[108], "%07o", 0); /* uid */
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sprintf(&header[116], "%07o", 0); /* gid */
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strncpy(&header[265], "git", 31); /* uname */
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strncpy(&header[297], "git", 31); /* gname */
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if (S_ISDIR(mode) || S_ISLNK(mode))
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size = 0;
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sprintf(&header[124], "%011lo", size);
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sprintf(&header[136], "%011lo", archive_time);
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header[156] = typeflag;
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memcpy(&header[257], "ustar", 6);
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memcpy(&header[263], "00", 2);
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sprintf(&header[329], "%07o", 0); /* devmajor */
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sprintf(&header[337], "%07o", 0); /* devminor */
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memset(&header[148], ' ', 8);
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for (i = 0; i < RECORDSIZE; i++)
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checksum += header[i];
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sprintf(&header[148], "%07o", checksum & 0x1fffff);
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write_if_needed();
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}
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static void traverse_tree(struct tree_desc *tree,
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struct path_prefix *prefix)
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{
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struct path_prefix this_prefix;
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this_prefix.prev = prefix;
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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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write_header(sha1, TYPEFLAG_AUTO, basedir,
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prefix, name, 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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this_prefix.name = name;
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traverse_tree(&subtree, &this_prefix);
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} else if (!S_ISLNK(mode)) {
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write_blocked(eltbuf, eltsize);
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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];
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struct commit *commit;
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struct tree_desc tree;
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setup_git_directory();
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switch (argc) {
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case 3:
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basedir = argv[2];
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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(sha1);
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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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}
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tree.buf = read_object_with_reference(sha1, "tree", &tree.size, NULL);
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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 (!archive_time)
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archive_time = time(NULL);
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if (basedir)
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write_header((unsigned char *)"0", TYPEFLAG_DIR, NULL, NULL,
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basedir, 040777, NULL, 0);
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traverse_tree(&tree, NULL);
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write_trailer();
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return 0;
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}
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