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1 | #include "cache.h" | |
2 | ||
3 | /* | |
4 | * Do not use this for inspecting *tracked* content. When path is a | |
5 | * symlink to a directory, we do not want to say it is a directory when | |
6 | * dealing with tracked content in the working tree. | |
7 | */ | |
8 | int is_directory(const char *path) | |
9 | { | |
10 | struct stat st; | |
11 | return (!stat(path, &st) && S_ISDIR(st.st_mode)); | |
12 | } | |
13 | ||
14 | /* removes the last path component from 'path' except if 'path' is root */ | |
15 | static void strip_last_component(struct strbuf *path) | |
16 | { | |
17 | size_t offset = offset_1st_component(path->buf); | |
18 | size_t len = path->len; | |
19 | ||
20 | /* Find start of the last component */ | |
21 | while (offset < len && !is_dir_sep(path->buf[len - 1])) | |
22 | len--; | |
23 | /* Skip sequences of multiple path-separators */ | |
24 | while (offset < len && is_dir_sep(path->buf[len - 1])) | |
25 | len--; | |
26 | ||
27 | strbuf_setlen(path, len); | |
28 | } | |
29 | ||
30 | /* get (and remove) the next component in 'remaining' and place it in 'next' */ | |
31 | static void get_next_component(struct strbuf *next, struct strbuf *remaining) | |
32 | { | |
33 | char *start = NULL; | |
34 | char *end = NULL; | |
35 | ||
36 | strbuf_reset(next); | |
37 | ||
38 | /* look for the next component */ | |
39 | /* Skip sequences of multiple path-separators */ | |
40 | for (start = remaining->buf; is_dir_sep(*start); start++) | |
41 | ; /* nothing */ | |
42 | /* Find end of the path component */ | |
43 | for (end = start; *end && !is_dir_sep(*end); end++) | |
44 | ; /* nothing */ | |
45 | ||
46 | strbuf_add(next, start, end - start); | |
47 | /* remove the component from 'remaining' */ | |
48 | strbuf_remove(remaining, 0, end - remaining->buf); | |
49 | } | |
50 | ||
51 | /* copies root part from remaining to resolved, canonicalizing it on the way */ | |
52 | static void get_root_part(struct strbuf *resolved, struct strbuf *remaining) | |
53 | { | |
54 | int offset = offset_1st_component(remaining->buf); | |
55 | ||
56 | strbuf_reset(resolved); | |
57 | strbuf_add(resolved, remaining->buf, offset); | |
58 | #ifdef GIT_WINDOWS_NATIVE | |
59 | convert_slashes(resolved->buf); | |
60 | #endif | |
61 | strbuf_remove(remaining, 0, offset); | |
62 | } | |
63 | ||
64 | /* We allow "recursive" symbolic links. Only within reason, though. */ | |
65 | #ifndef MAXSYMLINKS | |
66 | #define MAXSYMLINKS 32 | |
67 | #endif | |
68 | ||
69 | /* | |
70 | * If set, any number of trailing components may be missing; otherwise, only one | |
71 | * may be. | |
72 | */ | |
73 | #define REALPATH_MANY_MISSING (1 << 0) | |
74 | /* Should we die if there's an error? */ | |
75 | #define REALPATH_DIE_ON_ERROR (1 << 1) | |
76 | ||
77 | static char *strbuf_realpath_1(struct strbuf *resolved, const char *path, | |
78 | int flags) | |
79 | { | |
80 | struct strbuf remaining = STRBUF_INIT; | |
81 | struct strbuf next = STRBUF_INIT; | |
82 | struct strbuf symlink = STRBUF_INIT; | |
83 | char *retval = NULL; | |
84 | int num_symlinks = 0; | |
85 | struct stat st; | |
86 | ||
87 | if (!*path) { | |
88 | if (flags & REALPATH_DIE_ON_ERROR) | |
89 | die("The empty string is not a valid path"); | |
90 | else | |
91 | goto error_out; | |
92 | } | |
93 | ||
94 | strbuf_addstr(&remaining, path); | |
95 | get_root_part(resolved, &remaining); | |
96 | ||
97 | if (!resolved->len) { | |
98 | /* relative path; can use CWD as the initial resolved path */ | |
99 | if (strbuf_getcwd(resolved)) { | |
100 | if (flags & REALPATH_DIE_ON_ERROR) | |
101 | die_errno("unable to get current working directory"); | |
102 | else | |
103 | goto error_out; | |
104 | } | |
105 | } | |
106 | ||
107 | /* Iterate over the remaining path components */ | |
108 | while (remaining.len > 0) { | |
109 | get_next_component(&next, &remaining); | |
110 | ||
111 | if (next.len == 0) { | |
112 | continue; /* empty component */ | |
113 | } else if (next.len == 1 && !strcmp(next.buf, ".")) { | |
114 | continue; /* '.' component */ | |
115 | } else if (next.len == 2 && !strcmp(next.buf, "..")) { | |
116 | /* '..' component; strip the last path component */ | |
117 | strip_last_component(resolved); | |
118 | continue; | |
119 | } | |
120 | ||
121 | /* append the next component and resolve resultant path */ | |
122 | if (!is_dir_sep(resolved->buf[resolved->len - 1])) | |
123 | strbuf_addch(resolved, '/'); | |
124 | strbuf_addbuf(resolved, &next); | |
125 | ||
126 | if (lstat(resolved->buf, &st)) { | |
127 | /* error out unless this was the last component */ | |
128 | if (errno != ENOENT || | |
129 | (!(flags & REALPATH_MANY_MISSING) && remaining.len)) { | |
130 | if (flags & REALPATH_DIE_ON_ERROR) | |
131 | die_errno("Invalid path '%s'", | |
132 | resolved->buf); | |
133 | else | |
134 | goto error_out; | |
135 | } | |
136 | } else if (S_ISLNK(st.st_mode)) { | |
137 | ssize_t len; | |
138 | strbuf_reset(&symlink); | |
139 | ||
140 | if (num_symlinks++ > MAXSYMLINKS) { | |
141 | errno = ELOOP; | |
142 | ||
143 | if (flags & REALPATH_DIE_ON_ERROR) | |
144 | die("More than %d nested symlinks " | |
145 | "on path '%s'", MAXSYMLINKS, path); | |
146 | else | |
147 | goto error_out; | |
148 | } | |
149 | ||
150 | len = strbuf_readlink(&symlink, resolved->buf, | |
151 | st.st_size); | |
152 | if (len < 0) { | |
153 | if (flags & REALPATH_DIE_ON_ERROR) | |
154 | die_errno("Invalid symlink '%s'", | |
155 | resolved->buf); | |
156 | else | |
157 | goto error_out; | |
158 | } | |
159 | ||
160 | if (is_absolute_path(symlink.buf)) { | |
161 | /* absolute symlink; set resolved to root */ | |
162 | get_root_part(resolved, &symlink); | |
163 | } else { | |
164 | /* | |
165 | * relative symlink | |
166 | * strip off the last component since it will | |
167 | * be replaced with the contents of the symlink | |
168 | */ | |
169 | strip_last_component(resolved); | |
170 | } | |
171 | ||
172 | /* | |
173 | * if there are still remaining components to resolve | |
174 | * then append them to symlink | |
175 | */ | |
176 | if (remaining.len) { | |
177 | strbuf_addch(&symlink, '/'); | |
178 | strbuf_addbuf(&symlink, &remaining); | |
179 | } | |
180 | ||
181 | /* | |
182 | * use the symlink as the remaining components that | |
183 | * need to be resolved | |
184 | */ | |
185 | strbuf_swap(&symlink, &remaining); | |
186 | } | |
187 | } | |
188 | ||
189 | retval = resolved->buf; | |
190 | ||
191 | error_out: | |
192 | strbuf_release(&remaining); | |
193 | strbuf_release(&next); | |
194 | strbuf_release(&symlink); | |
195 | ||
196 | if (!retval) | |
197 | strbuf_reset(resolved); | |
198 | ||
199 | return retval; | |
200 | } | |
201 | ||
202 | /* | |
203 | * Return the real path (i.e., absolute path, with symlinks resolved | |
204 | * and extra slashes removed) equivalent to the specified path. (If | |
205 | * you want an absolute path but don't mind links, use | |
206 | * absolute_path().) Places the resolved realpath in the provided strbuf. | |
207 | * | |
208 | * The directory part of path (i.e., everything up to the last | |
209 | * dir_sep) must denote a valid, existing directory, but the last | |
210 | * component need not exist. If die_on_error is set, then die with an | |
211 | * informative error message if there is a problem. Otherwise, return | |
212 | * NULL on errors (without generating any output). | |
213 | */ | |
214 | char *strbuf_realpath(struct strbuf *resolved, const char *path, | |
215 | int die_on_error) | |
216 | { | |
217 | return strbuf_realpath_1(resolved, path, | |
218 | die_on_error ? REALPATH_DIE_ON_ERROR : 0); | |
219 | } | |
220 | ||
221 | /* | |
222 | * Just like strbuf_realpath, but allows an arbitrary number of path | |
223 | * components to be missing. | |
224 | */ | |
225 | char *strbuf_realpath_forgiving(struct strbuf *resolved, const char *path, | |
226 | int die_on_error) | |
227 | { | |
228 | return strbuf_realpath_1(resolved, path, | |
229 | ((die_on_error ? REALPATH_DIE_ON_ERROR : 0) | | |
230 | REALPATH_MANY_MISSING)); | |
231 | } | |
232 | ||
233 | char *real_pathdup(const char *path, int die_on_error) | |
234 | { | |
235 | struct strbuf realpath = STRBUF_INIT; | |
236 | char *retval = NULL; | |
237 | ||
238 | if (strbuf_realpath(&realpath, path, die_on_error)) | |
239 | retval = strbuf_detach(&realpath, NULL); | |
240 | ||
241 | strbuf_release(&realpath); | |
242 | ||
243 | return retval; | |
244 | } | |
245 | ||
246 | /* | |
247 | * Use this to get an absolute path from a relative one. If you want | |
248 | * to resolve links, you should use strbuf_realpath. | |
249 | */ | |
250 | const char *absolute_path(const char *path) | |
251 | { | |
252 | static struct strbuf sb = STRBUF_INIT; | |
253 | strbuf_reset(&sb); | |
254 | strbuf_add_absolute_path(&sb, path); | |
255 | return sb.buf; | |
256 | } | |
257 | ||
258 | char *absolute_pathdup(const char *path) | |
259 | { | |
260 | struct strbuf sb = STRBUF_INIT; | |
261 | strbuf_add_absolute_path(&sb, path); | |
262 | return strbuf_detach(&sb, NULL); | |
263 | } | |
264 | ||
265 | char *prefix_filename(const char *pfx, const char *arg) | |
266 | { | |
267 | struct strbuf path = STRBUF_INIT; | |
268 | size_t pfx_len = pfx ? strlen(pfx) : 0; | |
269 | ||
270 | if (!pfx_len) | |
271 | ; /* nothing to prefix */ | |
272 | else if (is_absolute_path(arg)) | |
273 | pfx_len = 0; | |
274 | else | |
275 | strbuf_add(&path, pfx, pfx_len); | |
276 | ||
277 | strbuf_addstr(&path, arg); | |
278 | #ifdef GIT_WINDOWS_NATIVE | |
279 | convert_slashes(path.buf + pfx_len); | |
280 | #endif | |
281 | return strbuf_detach(&path, NULL); | |
282 | } |