summaryrefslogtreecommitdiff
path: root/abspath.c
blob: 8c6c76b05e397c96811ea213177b1314c74f7c7d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
#include "cache.h"
 
/*
 * Do not use this for inspecting *tracked* content.  When path is a
 * symlink to a directory, we do not want to say it is a directory when
 * dealing with tracked content in the working tree.
 */
int is_directory(const char *path)
{
	struct stat st;
	return (!stat(path, &st) && S_ISDIR(st.st_mode));
}
 
/* removes the last path component from 'path' except if 'path' is root */
static void strip_last_component(struct strbuf *path)
{
	size_t offset = offset_1st_component(path->buf);
	size_t len = path->len;
 
	/* Find start of the last component */
	while (offset < len && !is_dir_sep(path->buf[len - 1]))
		len--;
	/* Skip sequences of multiple path-separators */
	while (offset < len && is_dir_sep(path->buf[len - 1]))
		len--;
 
	strbuf_setlen(path, len);
}
 
/* get (and remove) the next component in 'remaining' and place it in 'next' */
static void get_next_component(struct strbuf *next, struct strbuf *remaining)
{
	char *start = NULL;
	char *end = NULL;
 
	strbuf_reset(next);
 
	/* look for the next component */
	/* Skip sequences of multiple path-separators */
	for (start = remaining->buf; is_dir_sep(*start); start++)
		; /* nothing */
	/* Find end of the path component */
	for (end = start; *end && !is_dir_sep(*end); end++)
		; /* nothing */
 
	strbuf_add(next, start, end - start);
	/* remove the component from 'remaining' */
	strbuf_remove(remaining, 0, end - remaining->buf);
}
 
/* We allow "recursive" symbolic links. Only within reason, though. */
#define MAXSYMLINKS 5
 
/*
 * Return the real path (i.e., absolute path, with symlinks resolved
 * and extra slashes removed) equivalent to the specified path.  (If
 * you want an absolute path but don't mind links, use
 * absolute_path().)  Places the resolved realpath in the provided strbuf.
 *
 * The directory part of path (i.e., everything up to the last
 * dir_sep) must denote a valid, existing directory, but the last
 * component need not exist.  If die_on_error is set, then die with an
 * informative error message if there is a problem.  Otherwise, return
 * NULL on errors (without generating any output).
 */
char *strbuf_realpath(struct strbuf *resolved, const char *path,
		      int die_on_error)
{
	struct strbuf remaining = STRBUF_INIT;
	struct strbuf next = STRBUF_INIT;
	struct strbuf symlink = STRBUF_INIT;
	char *retval = NULL;
	int num_symlinks = 0;
	struct stat st;
 
	if (!*path) {
		if (die_on_error)
			die("The empty string is not a valid path");
		else
			goto error_out;
	}
 
	strbuf_reset(resolved);
 
	if (is_absolute_path(path)) {
		/* absolute path; start with only root as being resolved */
		int offset = offset_1st_component(path);
		strbuf_add(resolved, path, offset);
		strbuf_addstr(&remaining, path + offset);
	} else {
		/* relative path; can use CWD as the initial resolved path */
		if (strbuf_getcwd(resolved)) {
			if (die_on_error)
				die_errno("unable to get current working directory");
			else
				goto error_out;
		}
		strbuf_addstr(&remaining, path);
	}
 
	/* Iterate over the remaining path components */
	while (remaining.len > 0) {
		get_next_component(&next, &remaining);
 
		if (next.len == 0) {
			continue; /* empty component */
		} else if (next.len == 1 && !strcmp(next.buf, ".")) {
			continue; /* '.' component */
		} else if (next.len == 2 && !strcmp(next.buf, "..")) {
			/* '..' component; strip the last path component */
			strip_last_component(resolved);
			continue;
		}
 
		/* append the next component and resolve resultant path */
		if (!is_dir_sep(resolved->buf[resolved->len - 1]))
			strbuf_addch(resolved, '/');
		strbuf_addbuf(resolved, &next);
 
		if (lstat(resolved->buf, &st)) {
			/* error out unless this was the last component */
			if (errno != ENOENT || remaining.len) {
				if (die_on_error)
					die_errno("Invalid path '%s'",
						  resolved->buf);
				else
					goto error_out;
			}
		} else if (S_ISLNK(st.st_mode)) {
			ssize_t len;
			strbuf_reset(&symlink);
 
			if (num_symlinks++ > MAXSYMLINKS) {
				if (die_on_error)
					die("More than %d nested symlinks "
					    "on path '%s'", MAXSYMLINKS, path);
				else
					goto error_out;
			}
 
			len = strbuf_readlink(&symlink, resolved->buf,
					      st.st_size);
			if (len < 0) {
				if (die_on_error)
					die_errno("Invalid symlink '%s'",
						  resolved->buf);
				else
					goto error_out;
			}
 
			if (is_absolute_path(symlink.buf)) {
				/* absolute symlink; set resolved to root */
				int offset = offset_1st_component(symlink.buf);
				strbuf_reset(resolved);
				strbuf_add(resolved, symlink.buf, offset);
				strbuf_remove(&symlink, 0, offset);
			} else {
				/*
				 * relative symlink
				 * strip off the last component since it will
				 * be replaced with the contents of the symlink
				 */
				strip_last_component(resolved);
			}
 
			/*
			 * if there are still remaining components to resolve
			 * then append them to symlink
			 */
			if (remaining.len) {
				strbuf_addch(&symlink, '/');
				strbuf_addbuf(&symlink, &remaining);
			}
 
			/*
			 * use the symlink as the remaining components that
			 * need to be resloved
			 */
			strbuf_swap(&symlink, &remaining);
		}
	}
 
	retval = resolved->buf;
 
error_out:
	strbuf_release(&remaining);
	strbuf_release(&next);
	strbuf_release(&symlink);
 
	if (!retval)
		strbuf_reset(resolved);
 
	return retval;
}
 
const char *real_path(const char *path)
{
	static struct strbuf realpath = STRBUF_INIT;
	return strbuf_realpath(&realpath, path, 1);
}
 
const char *real_path_if_valid(const char *path)
{
	static struct strbuf realpath = STRBUF_INIT;
	return strbuf_realpath(&realpath, path, 0);
}
 
/*
 * Use this to get an absolute path from a relative one. If you want
 * to resolve links, you should use real_path.
 */
const char *absolute_path(const char *path)
{
	static struct strbuf sb = STRBUF_INIT;
	strbuf_reset(&sb);
	strbuf_add_absolute_path(&sb, path);
	return sb.buf;
}
 
/*
 * Unlike prefix_path, this should be used if the named file does
 * not have to interact with index entry; i.e. name of a random file
 * on the filesystem.
 */
const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
{
	static struct strbuf path = STRBUF_INIT;
#ifndef GIT_WINDOWS_NATIVE
	if (!pfx_len || is_absolute_path(arg))
		return arg;
	strbuf_reset(&path);
	strbuf_add(&path, pfx, pfx_len);
	strbuf_addstr(&path, arg);
#else
	/* don't add prefix to absolute paths, but still replace '\' by '/' */
	strbuf_reset(&path);
	if (is_absolute_path(arg))
		pfx_len = 0;
	else if (pfx_len)
		strbuf_add(&path, pfx, pfx_len);
	strbuf_addstr(&path, arg);
	convert_slashes(path.buf + pfx_len);
#endif
	return path.buf;
}