Add NO_C99_FORMAT to support older compilers.
[git/git.git] / mktag.c
CommitLineData
ec4465ad 1#include "cache.h"
8e440259 2#include "tag.h"
ec4465ad
LT
3
4/*
446c6fae
RJ
5 * A signature file has a very simple fixed format: four lines
6 * of "object <sha1>" + "type <typename>" + "tag <tagname>" +
7 * "tagger <committer>", followed by a blank line, a free-form tag
8 * message and a signature block that git itself doesn't care about,
9 * but that can be verified with gpg or similar.
ec4465ad
LT
10 *
11 * The first three lines are guaranteed to be at least 63 bytes:
12 * "object <sha1>\n" is 48 bytes, "type tag\n" at 9 bytes is the
13 * shortest possible type-line, and "tag .\n" at 6 bytes is the
14 * shortest single-character-tag line.
15 *
16 * We also artificially limit the size of the full object to 8kB.
17 * Just because I'm a lazy bastard, and if you can't fit a signature
18 * in that size, you're doing something wrong.
19 */
20
a9486b02 21/* Some random size */
ec4465ad
LT
22#define MAXSIZE (8192)
23
24/*
25 * We refuse to tag something we can't verify. Just because.
26 */
27static int verify_object(unsigned char *sha1, const char *expected_type)
28{
29 int ret = -1;
91d7b8af
NP
30 char type[100];
31 unsigned long size;
32 void *buffer = read_sha1_file(sha1, type, &size);
ec4465ad 33
91d7b8af
NP
34 if (buffer) {
35 if (!strcmp(type, expected_type))
36 ret = check_sha1_signature(sha1, buffer, size, type);
37 free(buffer);
ec4465ad
LT
38 }
39 return ret;
40}
41
579d1fbf
RJ
42#ifdef NO_C99_FORMAT
43#define PD_FMT "%d"
44#else
45#define PD_FMT "%td"
46#endif
47
ec4465ad
LT
48static int verify_tag(char *buffer, unsigned long size)
49{
50 int typelen;
51 char type[20];
52 unsigned char sha1[20];
c818566d 53 const char *object, *type_line, *tag_line, *tagger_line;
ec4465ad 54
e7332f96 55 if (size < 64)
446c6fae 56 return error("wanna fool me ? you obviously got the size wrong !");
cfba0459 57
ec4465ad
LT
58 buffer[size] = 0;
59
60 /* Verify object line */
61 object = buffer;
62 if (memcmp(object, "object ", 7))
446c6fae 63 return error("char%d: does not start with \"object \"", 0);
cfba0459 64
ec4465ad 65 if (get_sha1_hex(object + 7, sha1))
446c6fae 66 return error("char%d: could not get SHA1 hash", 7);
ec4465ad
LT
67
68 /* Verify type line */
69 type_line = object + 48;
70 if (memcmp(type_line - 1, "\ntype ", 6))
446c6fae 71 return error("char%d: could not find \"\\ntype \"", 47);
ec4465ad
LT
72
73 /* Verify tag-line */
74 tag_line = strchr(type_line, '\n');
75 if (!tag_line)
579d1fbf 76 return error("char" PD_FMT ": could not find next \"\\n\"", type_line - buffer);
ec4465ad
LT
77 tag_line++;
78 if (memcmp(tag_line, "tag ", 4) || tag_line[4] == '\n')
579d1fbf 79 return error("char" PD_FMT ": no \"tag \" found", tag_line - buffer);
ec4465ad
LT
80
81 /* Get the actual type */
82 typelen = tag_line - type_line - strlen("type \n");
83 if (typelen >= sizeof(type))
579d1fbf 84 return error("char" PD_FMT ": type too long", type_line+5 - buffer);
cfba0459 85
ec4465ad
LT
86 memcpy(type, type_line+5, typelen);
87 type[typelen] = 0;
88
89 /* Verify that the object matches */
ec4465ad 90 if (verify_object(sha1, type))
446c6fae 91 return error("char%d: could not verify object %s", 7, sha1_to_hex(sha1));
ec4465ad
LT
92
93 /* Verify the tag-name: we don't allow control characters or spaces in it */
94 tag_line += 4;
95 for (;;) {
96 unsigned char c = *tag_line++;
97 if (c == '\n')
98 break;
99 if (c > ' ')
100 continue;
579d1fbf 101 return error("char" PD_FMT ": could not verify tag name", tag_line - buffer);
ec4465ad
LT
102 }
103
c818566d
EB
104 /* Verify the tagger line */
105 tagger_line = tag_line;
106
107 if (memcmp(tagger_line, "tagger", 6) || (tagger_line[6] == '\n'))
579d1fbf 108 return error("char" PD_FMT ": could not find \"tagger\"", tagger_line - buffer);
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RJ
109
110 /* TODO: check for committer info + blank line? */
111 /* Also, the minimum length is probably + "tagger .", or 63+8=71 */
c818566d 112
ec4465ad
LT
113 /* The actual stuff afterwards we don't care about.. */
114 return 0;
115}
116
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RJ
117#undef PD_FMT
118
ec4465ad
LT
119int main(int argc, char **argv)
120{
e7332f96
BE
121 unsigned long size = 4096;
122 char *buffer = malloc(size);
ec4465ad
LT
123 unsigned char result_sha1[20];
124
125 if (argc != 1)
126 usage("cat <signaturefile> | git-mktag");
127
53228a5f
JH
128 setup_git_directory();
129
e7332f96
BE
130 if (read_pipe(0, &buffer, &size)) {
131 free(buffer);
132 die("could not read from stdin");
b97e3dfa 133 }
ec4465ad 134
a9486b02
PR
135 /* Verify it for some basic sanity: it needs to start with
136 "object <sha1>\ntype\ntagger " */
ec4465ad
LT
137 if (verify_tag(buffer, size) < 0)
138 die("invalid tag signature file");
139
8e440259 140 if (write_sha1_file(buffer, size, tag_type, result_sha1) < 0)
ec4465ad 141 die("unable to write tag file");
e7332f96
BE
142
143 free(buffer);
144
ec4465ad
LT
145 printf("%s\n", sha1_to_hex(result_sha1));
146 return 0;
147}