gpg: centralize signature check
[git] / builtin / verify-commit.c
1 /*
2  * Builtin "git commit-commit"
3  *
4  * Copyright (c) 2014 Michael J Gruber <git@drmicha.warpmail.net>
5  *
6  * Based on git-verify-tag
7  */
8 #include "cache.h"
9 #include "builtin.h"
10 #include "commit.h"
11 #include "run-command.h"
12 #include <signal.h>
13 #include "parse-options.h"
14 #include "gpg-interface.h"
15
16 static const char * const verify_commit_usage[] = {
17                 N_("git verify-commit [-v | --verbose] <commit>..."),
18                 NULL
19 };
20
21 static int run_gpg_verify(const unsigned char *sha1, const char *buf, unsigned long size, int verbose)
22 {
23         struct signature_check signature_check;
24         int ret;
25
26         memset(&signature_check, 0, sizeof(signature_check));
27
28         ret = check_commit_signature(lookup_commit(sha1), &signature_check);
29
30         if (verbose && signature_check.payload)
31                 fputs(signature_check.payload, stdout);
32
33         if (signature_check.gpg_output)
34                 fputs(signature_check.gpg_output, stderr);
35
36         signature_check_clear(&signature_check);
37         return ret;
38 }
39
40 static int verify_commit(const char *name, int verbose)
41 {
42         enum object_type type;
43         unsigned char sha1[20];
44         char *buf;
45         unsigned long size;
46         int ret;
47
48         if (get_sha1(name, sha1))
49                 return error("commit '%s' not found.", name);
50
51         buf = read_sha1_file(sha1, &type, &size);
52         if (!buf)
53                 return error("%s: unable to read file.", name);
54         if (type != OBJ_COMMIT)
55                 return error("%s: cannot verify a non-commit object of type %s.",
56                                 name, typename(type));
57
58         ret = run_gpg_verify(sha1, buf, size, verbose);
59
60         free(buf);
61         return ret;
62 }
63
64 static int git_verify_commit_config(const char *var, const char *value, void *cb)
65 {
66         int status = git_gpg_config(var, value, cb);
67         if (status)
68                 return status;
69         return git_default_config(var, value, cb);
70 }
71
72 int cmd_verify_commit(int argc, const char **argv, const char *prefix)
73 {
74         int i = 1, verbose = 0, had_error = 0;
75         const struct option verify_commit_options[] = {
76                 OPT__VERBOSE(&verbose, N_("print commit contents")),
77                 OPT_END()
78         };
79
80         git_config(git_verify_commit_config, NULL);
81
82         argc = parse_options(argc, argv, prefix, verify_commit_options,
83                              verify_commit_usage, PARSE_OPT_KEEP_ARGV0);
84         if (argc <= i)
85                 usage_with_options(verify_commit_usage, verify_commit_options);
86
87         /* sometimes the program was terminated because this signal
88          * was received in the process of writing the gpg input: */
89         signal(SIGPIPE, SIG_IGN);
90         while (i < argc)
91                 if (verify_commit(argv[i++], verbose))
92                         had_error = 1;
93         return had_error;
94 }