diff-files: careful when inspecting work tree items
[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
a6080a0a 14 * shortest single-character-tag line.
ec4465ad
LT
15 */
16
ec4465ad
LT
17/*
18 * We refuse to tag something we can't verify. Just because.
19 */
20static int verify_object(unsigned char *sha1, const char *expected_type)
21{
22 int ret = -1;
21666f1a 23 enum object_type type;
91d7b8af 24 unsigned long size;
21666f1a 25 void *buffer = read_sha1_file(sha1, &type, &size);
ec4465ad 26
91d7b8af 27 if (buffer) {
21666f1a
NP
28 if (type == type_from_string(expected_type))
29 ret = check_sha1_signature(sha1, buffer, size, expected_type);
91d7b8af 30 free(buffer);
ec4465ad
LT
31 }
32 return ret;
33}
34
579d1fbf
RJ
35#ifdef NO_C99_FORMAT
36#define PD_FMT "%d"
37#else
38#define PD_FMT "%td"
39#endif
40
ec4465ad
LT
41static int verify_tag(char *buffer, unsigned long size)
42{
43 int typelen;
44 char type[20];
45 unsigned char sha1[20];
c818566d 46 const char *object, *type_line, *tag_line, *tagger_line;
ec4465ad 47
e7332f96 48 if (size < 64)
446c6fae 49 return error("wanna fool me ? you obviously got the size wrong !");
cfba0459 50
ec4465ad
LT
51 buffer[size] = 0;
52
53 /* Verify object line */
54 object = buffer;
55 if (memcmp(object, "object ", 7))
446c6fae 56 return error("char%d: does not start with \"object \"", 0);
cfba0459 57
ec4465ad 58 if (get_sha1_hex(object + 7, sha1))
446c6fae 59 return error("char%d: could not get SHA1 hash", 7);
ec4465ad
LT
60
61 /* Verify type line */
62 type_line = object + 48;
63 if (memcmp(type_line - 1, "\ntype ", 6))
446c6fae 64 return error("char%d: could not find \"\\ntype \"", 47);
ec4465ad
LT
65
66 /* Verify tag-line */
67 tag_line = strchr(type_line, '\n');
68 if (!tag_line)
579d1fbf 69 return error("char" PD_FMT ": could not find next \"\\n\"", type_line - buffer);
ec4465ad
LT
70 tag_line++;
71 if (memcmp(tag_line, "tag ", 4) || tag_line[4] == '\n')
579d1fbf 72 return error("char" PD_FMT ": no \"tag \" found", tag_line - buffer);
ec4465ad
LT
73
74 /* Get the actual type */
75 typelen = tag_line - type_line - strlen("type \n");
76 if (typelen >= sizeof(type))
579d1fbf 77 return error("char" PD_FMT ": type too long", type_line+5 - buffer);
cfba0459 78
ec4465ad
LT
79 memcpy(type, type_line+5, typelen);
80 type[typelen] = 0;
81
82 /* Verify that the object matches */
ec4465ad 83 if (verify_object(sha1, type))
446c6fae 84 return error("char%d: could not verify object %s", 7, sha1_to_hex(sha1));
ec4465ad
LT
85
86 /* Verify the tag-name: we don't allow control characters or spaces in it */
87 tag_line += 4;
88 for (;;) {
89 unsigned char c = *tag_line++;
90 if (c == '\n')
91 break;
92 if (c > ' ')
93 continue;
579d1fbf 94 return error("char" PD_FMT ": could not verify tag name", tag_line - buffer);
ec4465ad
LT
95 }
96
c818566d
EB
97 /* Verify the tagger line */
98 tagger_line = tag_line;
99
100 if (memcmp(tagger_line, "tagger", 6) || (tagger_line[6] == '\n'))
579d1fbf 101 return error("char" PD_FMT ": could not find \"tagger\"", tagger_line - buffer);
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RJ
102
103 /* TODO: check for committer info + blank line? */
104 /* Also, the minimum length is probably + "tagger .", or 63+8=71 */
c818566d 105
ec4465ad
LT
106 /* The actual stuff afterwards we don't care about.. */
107 return 0;
108}
109
579d1fbf
RJ
110#undef PD_FMT
111
ec4465ad
LT
112int main(int argc, char **argv)
113{
fd17f5b5 114 struct strbuf buf;
ec4465ad
LT
115 unsigned char result_sha1[20];
116
117 if (argc != 1)
15e593e4 118 usage("git-mktag < signaturefile");
ec4465ad 119
53228a5f
JH
120 setup_git_directory();
121
fd17f5b5
PH
122 strbuf_init(&buf, 0);
123 if (strbuf_read(&buf, 0, 4096) < 0) {
e7332f96 124 die("could not read from stdin");
b97e3dfa 125 }
ec4465ad 126
a9486b02
PR
127 /* Verify it for some basic sanity: it needs to start with
128 "object <sha1>\ntype\ntagger " */
fd17f5b5 129 if (verify_tag(buf.buf, buf.len) < 0)
ec4465ad
LT
130 die("invalid tag signature file");
131
fd17f5b5 132 if (write_sha1_file(buf.buf, buf.len, tag_type, result_sha1) < 0)
ec4465ad 133 die("unable to write tag file");
e7332f96 134
fd17f5b5 135 strbuf_release(&buf);
ec4465ad
LT
136 printf("%s\n", sha1_to_hex(result_sha1));
137 return 0;
138}