revision parsing: make "rev -- paths" checks stronger.
[git/git.git] / setup.c
1 #include "cache.h"
2
3 const char *prefix_path(const char *prefix, int len, const char *path)
4 {
5 const char *orig = path;
6 for (;;) {
7 char c;
8 if (*path != '.')
9 break;
10 c = path[1];
11 /* "." */
12 if (!c) {
13 path++;
14 break;
15 }
16 /* "./" */
17 if (c == '/') {
18 path += 2;
19 continue;
20 }
21 if (c != '.')
22 break;
23 c = path[2];
24 if (!c)
25 path += 2;
26 else if (c == '/')
27 path += 3;
28 else
29 break;
30 /* ".." and "../" */
31 /* Remove last component of the prefix */
32 do {
33 if (!len)
34 die("'%s' is outside repository", orig);
35 len--;
36 } while (len && prefix[len-1] != '/');
37 continue;
38 }
39 if (len) {
40 int speclen = strlen(path);
41 char *n = xmalloc(speclen + len + 1);
42
43 memcpy(n, prefix, len);
44 memcpy(n + len, path, speclen+1);
45 path = n;
46 }
47 return path;
48 }
49
50 /*
51 * Unlike prefix_path, this should be used if the named file does
52 * not have to interact with index entry; i.e. name of a random file
53 * on the filesystem.
54 */
55 const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
56 {
57 static char path[PATH_MAX];
58 if (!pfx || !*pfx || arg[0] == '/')
59 return arg;
60 memcpy(path, pfx, pfx_len);
61 strcpy(path + pfx_len, arg);
62 return path;
63 }
64
65 /*
66 * Verify a filename that we got as an argument for a pathspec
67 * entry. Note that a filename that begins with "-" never verifies
68 * as true, because even if such a filename were to exist, we want
69 * it to be preceded by the "--" marker (or we want the user to
70 * use a format like "./-filename")
71 */
72 void verify_filename(const char *prefix, const char *arg)
73 {
74 const char *name;
75 struct stat st;
76
77 if (*arg == '-')
78 die("bad flag '%s' used after filename", arg);
79 name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
80 if (!lstat(name, &st))
81 return;
82 if (errno == ENOENT)
83 die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
84 "Use '--' to separate paths from revisions", arg);
85 die("'%s': %s", arg, strerror(errno));
86 }
87
88 /*
89 * Opposite of the above: the command line did not have -- marker
90 * and we parsed the arg as a refname. It should not be interpretable
91 * as a filename.
92 */
93 void verify_non_filename(const char *prefix, const char *arg)
94 {
95 const char *name;
96 struct stat st;
97
98 if (*arg == '-')
99 return; /* flag */
100 name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
101 if (!lstat(name, &st))
102 die("ambiguous argument '%s': both revision and filename\n"
103 "Use '--' to separate filenames from revisions", arg);
104 if (errno != ENOENT)
105 die("'%s': %s", arg, strerror(errno));
106 }
107
108 const char **get_pathspec(const char *prefix, const char **pathspec)
109 {
110 const char *entry = *pathspec;
111 const char **p;
112 int prefixlen;
113
114 if (!prefix && !entry)
115 return NULL;
116
117 if (!entry) {
118 static const char *spec[2];
119 spec[0] = prefix;
120 spec[1] = NULL;
121 return spec;
122 }
123
124 /* Otherwise we have to re-write the entries.. */
125 p = pathspec;
126 prefixlen = prefix ? strlen(prefix) : 0;
127 do {
128 *p = prefix_path(prefix, prefixlen, entry);
129 } while ((entry = *++p) != NULL);
130 return (const char **) pathspec;
131 }
132
133 /*
134 * Test if it looks like we're at the top level git directory.
135 * We want to see:
136 *
137 * - either a .git/objects/ directory _or_ the proper
138 * GIT_OBJECT_DIRECTORY environment variable
139 * - a refs/ directory under ".git"
140 * - either a HEAD symlink or a HEAD file that is formatted as
141 * a proper "ref:".
142 */
143 static int is_toplevel_directory(void)
144 {
145 if (access(".git/refs/", X_OK) ||
146 access(getenv(DB_ENVIRONMENT) ?
147 getenv(DB_ENVIRONMENT) : ".git/objects/", X_OK) ||
148 validate_symref(".git/HEAD"))
149 return 0;
150 return 1;
151 }
152
153 const char *setup_git_directory_gently(int *nongit_ok)
154 {
155 static char cwd[PATH_MAX+1];
156 int len, offset;
157
158 /*
159 * If GIT_DIR is set explicitly, we're not going
160 * to do any discovery, but we still do repository
161 * validation.
162 */
163 if (getenv(GIT_DIR_ENVIRONMENT)) {
164 char path[PATH_MAX];
165 int len = strlen(getenv(GIT_DIR_ENVIRONMENT));
166 if (sizeof(path) - 40 < len)
167 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
168 memcpy(path, getenv(GIT_DIR_ENVIRONMENT), len);
169
170 strcpy(path + len, "/refs");
171 if (access(path, X_OK))
172 goto bad_dir_environ;
173 strcpy(path + len, "/HEAD");
174 if (validate_symref(path))
175 goto bad_dir_environ;
176 if (getenv(DB_ENVIRONMENT)) {
177 if (access(getenv(DB_ENVIRONMENT), X_OK))
178 goto bad_dir_environ;
179 }
180 else {
181 strcpy(path + len, "/objects");
182 if (access(path, X_OK))
183 goto bad_dir_environ;
184 }
185 return NULL;
186 bad_dir_environ:
187 path[len] = 0;
188 die("Not a git repository: '%s'", path);
189 }
190
191 if (!getcwd(cwd, sizeof(cwd)) || cwd[0] != '/')
192 die("Unable to read current working directory");
193
194 offset = len = strlen(cwd);
195 for (;;) {
196 if (is_toplevel_directory())
197 break;
198 chdir("..");
199 do {
200 if (!offset) {
201 if (nongit_ok) {
202 if (chdir(cwd))
203 die("Cannot come back to cwd");
204 *nongit_ok = 1;
205 return NULL;
206 }
207 die("Not a git repository");
208 }
209 } while (cwd[--offset] != '/');
210 }
211
212 if (offset == len)
213 return NULL;
214
215 /* Make "offset" point to past the '/', and add a '/' at the end */
216 offset++;
217 cwd[len++] = '/';
218 cwd[len] = 0;
219 return cwd + offset;
220 }
221
222 int check_repository_format_version(const char *var, const char *value)
223 {
224 if (strcmp(var, "core.repositoryformatversion") == 0)
225 repository_format_version = git_config_int(var, value);
226 else if (strcmp(var, "core.sharedrepository") == 0)
227 shared_repository = git_config_bool(var, value);
228 return 0;
229 }
230
231 int check_repository_format(void)
232 {
233 git_config(check_repository_format_version);
234 if (GIT_REPO_VERSION < repository_format_version)
235 die ("Expected git repo version <= %d, found %d",
236 GIT_REPO_VERSION, repository_format_version);
237 return 0;
238 }
239
240 const char *setup_git_directory(void)
241 {
242 const char *retval = setup_git_directory_gently(NULL);
243 check_repository_format();
244 return retval;
245 }