Sync with 2.25.1
[git.git] / builtin / get-tar-commit-id.c
blob491af9202dc937339db83980e2bf96de6ff81646
1 /*
2 * Copyright (c) 2005, 2006 Rene Scharfe
3 */
4 #include "cache.h"
5 #include "commit.h"
6 #include "tar.h"
7 #include "builtin.h"
8 #include "quote.h"
10 static const char builtin_get_tar_commit_id_usage[] =
11 "git get-tar-commit-id";
13 /* ustar header + extended global header content */
14 #define RECORDSIZE (512)
15 #define HEADERSIZE (2 * RECORDSIZE)
17 int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix)
19 char buffer[HEADERSIZE];
20 struct ustar_header *header = (struct ustar_header *)buffer;
21 char *content = buffer + RECORDSIZE;
22 const char *comment;
23 ssize_t n;
24 long len;
25 char *end;
27 if (argc != 1)
28 usage(builtin_get_tar_commit_id_usage);
30 n = read_in_full(0, buffer, HEADERSIZE);
31 if (n < 0)
32 die_errno("git get-tar-commit-id: read error");
33 if (n != HEADERSIZE)
34 die_errno("git get-tar-commit-id: EOF before reading tar header");
35 if (header->typeflag[0] != 'g')
36 return 1;
38 len = strtol(content, &end, 10);
39 if (errno == ERANGE || end == content || len < 0)
40 return 1;
41 if (!skip_prefix(end, " comment=", &comment))
42 return 1;
43 len -= comment - content;
44 if (len < 1 || !(len % 2) ||
45 hash_algo_by_length((len - 1) / 2) == GIT_HASH_UNKNOWN)
46 return 1;
48 if (write_in_full(1, comment, len) < 0)
49 die_errno("git get-tar-commit-id: write error");
51 return 0;