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https://github.com/git/git
synced 2024-08-28 20:20:07 +00:00
![René Scharfe](/assets/img/avatar_default.png)
Compression programs like zip, gzip, bzip2 and xz allow to adjust the trade-off between CPU cost and size gain with numerical options from -1 for fast compression and -9 for high compression ratio. zip also accepts -0 for storing files verbatim. git archive directly support these single-digit compression levels for ZIP output and passes them to filters like gzip. Zstandard additionally supports compression level options -10 to -19, or up to -22 with --ultra. This *seems* to work with git archive in most cases, e.g. it will produce an archive with -19 without complaining, but since it only supports single-digit compression level options this is the same as -1 -9 and thus -9. Allow git archive to accept multi-digit compression levels to support the full range supported by zstd. Explicitly reject them for the ZIP format, as otherwise deflateInit2() would just fail with a somewhat cryptic "stream consistency error". Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
488 lines
12 KiB
C
488 lines
12 KiB
C
/*
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* Copyright (c) 2005, 2006 Rene Scharfe
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*/
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#include "cache.h"
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#include "config.h"
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#include "tar.h"
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#include "archive.h"
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#include "object-store.h"
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#include "streaming.h"
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#include "run-command.h"
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#define RECORDSIZE (512)
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#define BLOCKSIZE (RECORDSIZE * 20)
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static char block[BLOCKSIZE];
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static unsigned long offset;
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static int tar_umask = 002;
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static int write_tar_filter_archive(const struct archiver *ar,
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struct archiver_args *args);
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/*
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* This is the max value that a ustar size header can specify, as it is fixed
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* at 11 octal digits. POSIX specifies that we switch to extended headers at
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* this size.
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*
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* Likewise for the mtime (which happens to use a buffer of the same size).
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*/
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#if ULONG_MAX == 0xFFFFFFFF
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#define USTAR_MAX_SIZE ULONG_MAX
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#else
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#define USTAR_MAX_SIZE 077777777777UL
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#endif
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#if TIME_MAX == 0xFFFFFFFF
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#define USTAR_MAX_MTIME TIME_MAX
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#else
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#define USTAR_MAX_MTIME 077777777777ULL
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#endif
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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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write_or_die(1, block, BLOCKSIZE);
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offset = 0;
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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 do_write_blocked(const void *data, unsigned long size)
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{
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const char *buf = data;
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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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write_or_die(1, 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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}
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static void finish_record(void)
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{
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unsigned long tail;
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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 write_blocked(const void *data, unsigned long size)
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{
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do_write_blocked(data, size);
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finish_record();
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}
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/*
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* The end of tar archives is marked by 2*512 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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int tail = BLOCKSIZE - offset;
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memset(block + offset, 0, tail);
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write_or_die(1, block, BLOCKSIZE);
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if (tail < 2 * RECORDSIZE) {
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memset(block, 0, offset);
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write_or_die(1, block, BLOCKSIZE);
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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 int stream_blocked(struct repository *r, const struct object_id *oid)
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{
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struct git_istream *st;
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enum object_type type;
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unsigned long sz;
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char buf[BLOCKSIZE];
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ssize_t readlen;
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st = open_istream(r, oid, &type, &sz, NULL);
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if (!st)
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return error(_("cannot stream blob %s"), oid_to_hex(oid));
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for (;;) {
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readlen = read_istream(st, buf, sizeof(buf));
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if (readlen <= 0)
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break;
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do_write_blocked(buf, readlen);
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}
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close_istream(st);
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if (!readlen)
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finish_record();
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return readlen;
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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, size_t valuelen)
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{
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size_t orig_len = sb->len;
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size_t len, 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 = 1; len / 10 >= tmp; tmp *= 10)
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len++;
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strbuf_grow(sb, len);
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strbuf_addf(sb, "%"PRIuMAX" %s=", (uintmax_t)len, keyword);
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strbuf_add(sb, value, valuelen);
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strbuf_addch(sb, '\n');
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if (len != sb->len - orig_len)
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BUG("pax extended header length miscalculated as %"PRIuMAX
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", should be %"PRIuMAX,
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(uintmax_t)len, (uintmax_t)(sb->len - orig_len));
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}
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/*
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* Like strbuf_append_ext_header, but for numeric values.
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*/
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static void strbuf_append_ext_header_uint(struct strbuf *sb,
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const char *keyword,
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uintmax_t value)
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{
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char buf[40]; /* big enough for 2^128 in decimal, plus NUL */
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int len;
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len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value);
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strbuf_append_ext_header(sb, keyword, buf, len);
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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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const unsigned char *p = (const unsigned char *)header;
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unsigned int chksum = 0;
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while (p < (const unsigned char *)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 < (const unsigned 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 size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
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{
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size_t i = pathlen;
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if (i > 1 && path[i - 1] == '/')
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i--;
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if (i > maxlen)
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i = maxlen;
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do {
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i--;
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} while (i > 0 && path[i] != '/');
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return i;
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}
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static void prepare_header(struct archiver_args *args,
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struct ustar_header *header,
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unsigned int mode, unsigned long size)
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{
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xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777);
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xsnprintf(header->size, sizeof(header->size), "%011"PRIoMAX , S_ISREG(mode) ? (uintmax_t)size : (uintmax_t)0);
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xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time);
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xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
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xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
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strlcpy(header->uname, "root", sizeof(header->uname));
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strlcpy(header->gname, "root", sizeof(header->gname));
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xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0);
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xsnprintf(header->devminor, sizeof(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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xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header));
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}
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static void write_extended_header(struct archiver_args *args,
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const struct object_id *oid,
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const void *buffer, unsigned long size)
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{
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struct ustar_header header;
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unsigned int mode;
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memset(&header, 0, sizeof(header));
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*header.typeflag = TYPEFLAG_EXT_HEADER;
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mode = 0100666;
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xsnprintf(header.name, sizeof(header.name), "%s.paxheader", oid_to_hex(oid));
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prepare_header(args, &header, mode, size);
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write_blocked(&header, sizeof(header));
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write_blocked(buffer, size);
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}
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static int write_tar_entry(struct archiver_args *args,
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const struct object_id *oid,
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const char *path, size_t pathlen,
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unsigned int mode,
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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 = STRBUF_INIT;
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unsigned long size_in_header;
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int err = 0;
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memset(&header, 0, sizeof(header));
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if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
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*header.typeflag = TYPEFLAG_DIR;
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mode = (mode | 0777) & ~tar_umask;
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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 | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
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} else {
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return error(_("unsupported file mode: 0%o (SHA1: %s)"),
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mode, oid_to_hex(oid));
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}
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if (pathlen > sizeof(header.name)) {
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size_t plen = get_path_prefix(path, pathlen,
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sizeof(header.prefix));
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size_t rest = pathlen - plen - 1;
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if (plen > 0 && rest <= sizeof(header.name)) {
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memcpy(header.prefix, path, plen);
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memcpy(header.name, path + plen + 1, rest);
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} else {
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xsnprintf(header.name, sizeof(header.name), "%s.data",
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oid_to_hex(oid));
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strbuf_append_ext_header(&ext_header, "path",
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path, pathlen);
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}
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} else
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memcpy(header.name, path, pathlen);
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if (S_ISLNK(mode)) {
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if (size > sizeof(header.linkname)) {
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xsnprintf(header.linkname, sizeof(header.linkname),
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"see %s.paxheader", oid_to_hex(oid));
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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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size_in_header = size;
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if (S_ISREG(mode) && size > USTAR_MAX_SIZE) {
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size_in_header = 0;
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strbuf_append_ext_header_uint(&ext_header, "size", size);
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}
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prepare_header(args, &header, mode, size_in_header);
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if (ext_header.len > 0) {
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write_extended_header(args, oid, ext_header.buf,
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ext_header.len);
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}
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strbuf_release(&ext_header);
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write_blocked(&header, sizeof(header));
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if (S_ISREG(mode) && size > 0) {
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if (buffer)
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write_blocked(buffer, size);
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else
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err = stream_blocked(args->repo, oid);
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}
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return err;
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}
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static void write_global_extended_header(struct archiver_args *args)
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{
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const struct object_id *oid = args->commit_oid;
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struct strbuf ext_header = STRBUF_INIT;
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struct ustar_header header;
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unsigned int mode;
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if (oid)
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strbuf_append_ext_header(&ext_header, "comment",
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oid_to_hex(oid),
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the_hash_algo->hexsz);
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if (args->time > USTAR_MAX_MTIME) {
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strbuf_append_ext_header_uint(&ext_header, "mtime",
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args->time);
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args->time = USTAR_MAX_MTIME;
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}
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if (!ext_header.len)
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return;
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memset(&header, 0, sizeof(header));
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*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
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mode = 0100666;
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xsnprintf(header.name, sizeof(header.name), "pax_global_header");
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prepare_header(args, &header, mode, ext_header.len);
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write_blocked(&header, sizeof(header));
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write_blocked(ext_header.buf, ext_header.len);
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strbuf_release(&ext_header);
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}
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static struct archiver **tar_filters;
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static int nr_tar_filters;
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static int alloc_tar_filters;
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static struct archiver *find_tar_filter(const char *name, size_t len)
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{
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int i;
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for (i = 0; i < nr_tar_filters; i++) {
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struct archiver *ar = tar_filters[i];
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if (!strncmp(ar->name, name, len) && !ar->name[len])
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return ar;
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}
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return NULL;
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}
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static int tar_filter_config(const char *var, const char *value, void *data)
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{
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struct archiver *ar;
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const char *name;
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const char *type;
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size_t namelen;
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if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 || !name)
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return 0;
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ar = find_tar_filter(name, namelen);
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if (!ar) {
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ar = xcalloc(1, sizeof(*ar));
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ar->name = xmemdupz(name, namelen);
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ar->write_archive = write_tar_filter_archive;
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ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS |
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ARCHIVER_HIGH_COMPRESSION_LEVELS;
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ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
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tar_filters[nr_tar_filters++] = ar;
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}
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if (!strcmp(type, "command")) {
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if (!value)
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return config_error_nonbool(var);
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free(ar->data);
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ar->data = xstrdup(value);
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return 0;
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}
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if (!strcmp(type, "remote")) {
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if (git_config_bool(var, value))
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ar->flags |= ARCHIVER_REMOTE;
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else
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ar->flags &= ~ARCHIVER_REMOTE;
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return 0;
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}
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return 0;
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}
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static int git_tar_config(const char *var, const char *value, void *cb)
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{
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if (!strcmp(var, "tar.umask")) {
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if (value && !strcmp(value, "user")) {
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tar_umask = umask(0);
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umask(tar_umask);
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} else {
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tar_umask = git_config_int(var, value);
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}
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return 0;
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}
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return tar_filter_config(var, value, cb);
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}
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static int write_tar_archive(const struct archiver *ar,
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struct archiver_args *args)
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{
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int err = 0;
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write_global_extended_header(args);
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err = write_archive_entries(args, write_tar_entry);
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if (!err)
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write_trailer();
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return err;
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}
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static int write_tar_filter_archive(const struct archiver *ar,
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struct archiver_args *args)
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{
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struct strbuf cmd = STRBUF_INIT;
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struct child_process filter = CHILD_PROCESS_INIT;
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const char *argv[2];
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int r;
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if (!ar->data)
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BUG("tar-filter archiver called with no filter defined");
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strbuf_addstr(&cmd, ar->data);
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if (args->compression_level >= 0)
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strbuf_addf(&cmd, " -%d", args->compression_level);
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argv[0] = cmd.buf;
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argv[1] = NULL;
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filter.argv = argv;
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filter.use_shell = 1;
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filter.in = -1;
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if (start_command(&filter) < 0)
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die_errno(_("unable to start '%s' filter"), argv[0]);
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close(1);
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if (dup2(filter.in, 1) < 0)
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die_errno(_("unable to redirect descriptor"));
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close(filter.in);
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r = write_tar_archive(ar, args);
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close(1);
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if (finish_command(&filter) != 0)
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die(_("'%s' filter reported error"), argv[0]);
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strbuf_release(&cmd);
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return r;
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}
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static struct archiver tar_archiver = {
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"tar",
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write_tar_archive,
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ARCHIVER_REMOTE
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};
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void init_tar_archiver(void)
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{
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int i;
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register_archiver(&tar_archiver);
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tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
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tar_filter_config("tar.tgz.remote", "true", NULL);
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tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
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tar_filter_config("tar.tar.gz.remote", "true", NULL);
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git_config(git_tar_config, NULL);
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for (i = 0; i < nr_tar_filters; i++) {
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/* omit any filters that never had a command configured */
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if (tar_filters[i]->data)
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register_archiver(tar_filters[i]);
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}
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}
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