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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 | /* We allow "recursive" symbolic links. Only within reason, though. */ | |
15 | #define MAXDEPTH 5 | |
16 | ||
17 | /* | |
18 | * Return the real path (i.e., absolute path, with symlinks resolved | |
19 | * and extra slashes removed) equivalent to the specified path. (If | |
20 | * you want an absolute path but don't mind links, use | |
21 | * absolute_path().) The return value is a pointer to a static | |
22 | * buffer. | |
23 | * | |
24 | * The input and all intermediate paths must be shorter than MAX_PATH. | |
25 | * The directory part of path (i.e., everything up to the last | |
26 | * dir_sep) must denote a valid, existing directory, but the last | |
27 | * component need not exist. If die_on_error is set, then die with an | |
28 | * informative error message if there is a problem. Otherwise, return | |
29 | * NULL on errors (without generating any output). | |
30 | * | |
31 | * If path is our buffer, then return path, as it's already what the | |
32 | * user wants. | |
33 | */ | |
34 | static const char *real_path_internal(const char *path, int die_on_error) | |
35 | { | |
36 | static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1]; | |
37 | char *retval = NULL; | |
38 | ||
39 | /* | |
40 | * If we have to temporarily chdir(), store the original CWD | |
41 | * here so that we can chdir() back to it at the end of the | |
42 | * function: | |
43 | */ | |
44 | char cwd[1024] = ""; | |
45 | ||
46 | int buf_index = 1; | |
47 | ||
48 | int depth = MAXDEPTH; | |
49 | char *last_elem = NULL; | |
50 | struct stat st; | |
51 | ||
52 | /* We've already done it */ | |
53 | if (path == buf || path == next_buf) | |
54 | return path; | |
55 | ||
56 | if (!*path) { | |
57 | if (die_on_error) | |
58 | die("The empty string is not a valid path"); | |
59 | else | |
60 | goto error_out; | |
61 | } | |
62 | ||
63 | if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) { | |
64 | if (die_on_error) | |
65 | die("Too long path: %.*s", 60, path); | |
66 | else | |
67 | goto error_out; | |
68 | } | |
69 | ||
70 | while (depth--) { | |
71 | if (!is_directory(buf)) { | |
72 | char *last_slash = find_last_dir_sep(buf); | |
73 | if (last_slash) { | |
74 | last_elem = xstrdup(last_slash + 1); | |
75 | last_slash[1] = '\0'; | |
76 | } else { | |
77 | last_elem = xstrdup(buf); | |
78 | *buf = '\0'; | |
79 | } | |
80 | } | |
81 | ||
82 | if (*buf) { | |
83 | if (!*cwd && !getcwd(cwd, sizeof(cwd))) { | |
84 | if (die_on_error) | |
85 | die_errno("Could not get current working directory"); | |
86 | else | |
87 | goto error_out; | |
88 | } | |
89 | ||
90 | if (chdir(buf)) { | |
91 | if (die_on_error) | |
92 | die_errno("Could not switch to '%s'", buf); | |
93 | else | |
94 | goto error_out; | |
95 | } | |
96 | } | |
97 | if (!getcwd(buf, PATH_MAX)) { | |
98 | if (die_on_error) | |
99 | die_errno("Could not get current working directory"); | |
100 | else | |
101 | goto error_out; | |
102 | } | |
103 | ||
104 | if (last_elem) { | |
105 | size_t len = strlen(buf); | |
106 | if (len + strlen(last_elem) + 2 > PATH_MAX) { | |
107 | if (die_on_error) | |
108 | die("Too long path name: '%s/%s'", | |
109 | buf, last_elem); | |
110 | else | |
111 | goto error_out; | |
112 | } | |
113 | if (len && !is_dir_sep(buf[len-1])) | |
114 | buf[len++] = '/'; | |
115 | strcpy(buf + len, last_elem); | |
116 | free(last_elem); | |
117 | last_elem = NULL; | |
118 | } | |
119 | ||
120 | if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) { | |
121 | ssize_t len = readlink(buf, next_buf, PATH_MAX); | |
122 | if (len < 0) { | |
123 | if (die_on_error) | |
124 | die_errno("Invalid symlink '%s'", buf); | |
125 | else | |
126 | goto error_out; | |
127 | } | |
128 | if (PATH_MAX <= len) { | |
129 | if (die_on_error) | |
130 | die("symbolic link too long: %s", buf); | |
131 | else | |
132 | goto error_out; | |
133 | } | |
134 | next_buf[len] = '\0'; | |
135 | buf = next_buf; | |
136 | buf_index = 1 - buf_index; | |
137 | next_buf = bufs[buf_index]; | |
138 | } else | |
139 | break; | |
140 | } | |
141 | ||
142 | retval = buf; | |
143 | error_out: | |
144 | free(last_elem); | |
145 | if (*cwd && chdir(cwd)) | |
146 | die_errno ("Could not change back to '%s'", cwd); | |
147 | ||
148 | return retval; | |
149 | } | |
150 | ||
151 | const char *real_path(const char *path) | |
152 | { | |
153 | return real_path_internal(path, 1); | |
154 | } | |
155 | ||
156 | static const char *get_pwd_cwd(void) | |
157 | { | |
158 | static char cwd[PATH_MAX + 1]; | |
159 | char *pwd; | |
160 | struct stat cwd_stat, pwd_stat; | |
161 | if (getcwd(cwd, PATH_MAX) == NULL) | |
162 | return NULL; | |
163 | pwd = getenv("PWD"); | |
164 | if (pwd && strcmp(pwd, cwd)) { | |
165 | stat(cwd, &cwd_stat); | |
166 | if ((cwd_stat.st_dev || cwd_stat.st_ino) && | |
167 | !stat(pwd, &pwd_stat) && | |
168 | pwd_stat.st_dev == cwd_stat.st_dev && | |
169 | pwd_stat.st_ino == cwd_stat.st_ino) { | |
170 | strlcpy(cwd, pwd, PATH_MAX); | |
171 | } | |
172 | } | |
173 | return cwd; | |
174 | } | |
175 | ||
176 | /* | |
177 | * Use this to get an absolute path from a relative one. If you want | |
178 | * to resolve links, you should use real_path. | |
179 | * | |
180 | * If the path is already absolute, then return path. As the user is | |
181 | * never meant to free the return value, we're safe. | |
182 | */ | |
183 | const char *absolute_path(const char *path) | |
184 | { | |
185 | static char buf[PATH_MAX + 1]; | |
186 | ||
187 | if (!*path) { | |
188 | die("The empty string is not a valid path"); | |
189 | } else if (is_absolute_path(path)) { | |
190 | if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) | |
191 | die("Too long path: %.*s", 60, path); | |
192 | } else { | |
193 | size_t len; | |
194 | const char *fmt; | |
195 | const char *cwd = get_pwd_cwd(); | |
196 | if (!cwd) | |
197 | die_errno("Cannot determine the current working directory"); | |
198 | len = strlen(cwd); | |
199 | fmt = (len > 0 && is_dir_sep(cwd[len-1])) ? "%s%s" : "%s/%s"; | |
200 | if (snprintf(buf, PATH_MAX, fmt, cwd, path) >= PATH_MAX) | |
201 | die("Too long path: %.*s", 60, path); | |
202 | } | |
203 | return buf; | |
204 | } | |
205 | ||
206 | /* | |
207 | * Unlike prefix_path, this should be used if the named file does | |
208 | * not have to interact with index entry; i.e. name of a random file | |
209 | * on the filesystem. | |
210 | */ | |
211 | const char *prefix_filename(const char *pfx, int pfx_len, const char *arg) | |
212 | { | |
213 | static char path[PATH_MAX]; | |
214 | #ifndef WIN32 | |
215 | if (!pfx_len || is_absolute_path(arg)) | |
216 | return arg; | |
217 | memcpy(path, pfx, pfx_len); | |
218 | strcpy(path + pfx_len, arg); | |
219 | #else | |
220 | char *p; | |
221 | /* don't add prefix to absolute paths, but still replace '\' by '/' */ | |
222 | if (is_absolute_path(arg)) | |
223 | pfx_len = 0; | |
224 | else if (pfx_len) | |
225 | memcpy(path, pfx, pfx_len); | |
226 | strcpy(path + pfx_len, arg); | |
227 | for (p = path + pfx_len; *p; p++) | |
228 | if (*p == '\\') | |
229 | *p = '/'; | |
230 | #endif | |
231 | return path; | |
232 | } |