Update draft release notes to 1.8.0
[git/git.git] / abspath.c
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1#include "cache.h"
2
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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 */
8int is_directory(const char *path)
9{
10 struct stat st;
11 return (!stat(path, &st) && S_ISDIR(st.st_mode));
12}
13
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14/* We allow "recursive" symbolic links. Only within reason, though. */
15#define MAXDEPTH 5
16
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17/*
18 * Use this to get the real path, i.e. resolve links. If you want an
19 * absolute path but don't mind links, use absolute_path.
20 *
21 * If path is our buffer, then return path, as it's already what the
22 * user wants.
23 */
24const char *real_path(const char *path)
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25{
26 static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
27 char cwd[1024] = "";
1630726e 28 int buf_index = 1;
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29
30 int depth = MAXDEPTH;
31 char *last_elem = NULL;
32 struct stat st;
33
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34 /* We've already done it */
35 if (path == buf || path == next_buf)
36 return path;
37
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38 if (!*path)
39 die("The empty string is not a valid path");
40
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41 if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
42 die ("Too long path: %.*s", 60, path);
43
44 while (depth--) {
90b4a71c 45 if (!is_directory(buf)) {
d1c69255 46 char *last_slash = find_last_dir_sep(buf);
5b8e6f85 47 if (last_slash) {
5b8e6f85 48 last_elem = xstrdup(last_slash + 1);
f4c21e89 49 last_slash[1] = '\0';
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50 } else {
51 last_elem = xstrdup(buf);
52 *buf = '\0';
53 }
54 }
55
56 if (*buf) {
57 if (!*cwd && !getcwd(cwd, sizeof(cwd)))
0721c314 58 die_errno ("Could not get current working directory");
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59
60 if (chdir(buf))
0721c314 61 die_errno ("Could not switch to '%s'", buf);
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62 }
63 if (!getcwd(buf, PATH_MAX))
0721c314 64 die_errno ("Could not get current working directory");
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65
66 if (last_elem) {
1630726e 67 size_t len = strlen(buf);
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68 if (len + strlen(last_elem) + 2 > PATH_MAX)
69 die ("Too long path name: '%s/%s'",
70 buf, last_elem);
d1c69255 71 if (len && !is_dir_sep(buf[len-1]))
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72 buf[len++] = '/';
73 strcpy(buf + len, last_elem);
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74 free(last_elem);
75 last_elem = NULL;
76 }
77
78 if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
1630726e 79 ssize_t len = readlink(buf, next_buf, PATH_MAX);
5b8e6f85 80 if (len < 0)
0721c314 81 die_errno ("Invalid symlink '%s'", buf);
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82 if (PATH_MAX <= len)
83 die("symbolic link too long: %s", buf);
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84 next_buf[len] = '\0';
85 buf = next_buf;
86 buf_index = 1 - buf_index;
87 next_buf = bufs[buf_index];
88 } else
89 break;
90 }
91
92 if (*cwd && chdir(cwd))
0721c314 93 die_errno ("Could not change back to '%s'", cwd);
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94
95 return buf;
96}
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97
98static const char *get_pwd_cwd(void)
99{
100 static char cwd[PATH_MAX + 1];
101 char *pwd;
102 struct stat cwd_stat, pwd_stat;
103 if (getcwd(cwd, PATH_MAX) == NULL)
104 return NULL;
105 pwd = getenv("PWD");
106 if (pwd && strcmp(pwd, cwd)) {
107 stat(cwd, &cwd_stat);
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108 if ((cwd_stat.st_dev || cwd_stat.st_ino) &&
109 !stat(pwd, &pwd_stat) &&
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110 pwd_stat.st_dev == cwd_stat.st_dev &&
111 pwd_stat.st_ino == cwd_stat.st_ino) {
112 strlcpy(cwd, pwd, PATH_MAX);
113 }
114 }
115 return cwd;
116}
117
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118/*
119 * Use this to get an absolute path from a relative one. If you want
120 * to resolve links, you should use real_path.
121 *
122 * If the path is already absolute, then return path. As the user is
123 * never meant to free the return value, we're safe.
124 */
125const char *absolute_path(const char *path)
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126{
127 static char buf[PATH_MAX + 1];
128
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129 if (!*path) {
130 die("The empty string is not a valid path");
131 } else if (is_absolute_path(path)) {
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132 if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
133 die("Too long path: %.*s", 60, path);
134 } else {
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135 size_t len;
136 const char *fmt;
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137 const char *cwd = get_pwd_cwd();
138 if (!cwd)
0721c314 139 die_errno("Cannot determine the current working directory");
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140 len = strlen(cwd);
141 fmt = (len > 0 && is_dir_sep(cwd[len-1])) ? "%s%s" : "%s/%s";
142 if (snprintf(buf, PATH_MAX, fmt, cwd, path) >= PATH_MAX)
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143 die("Too long path: %.*s", 60, path);
144 }
145 return buf;
146}
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147
148/*
149 * Unlike prefix_path, this should be used if the named file does
150 * not have to interact with index entry; i.e. name of a random file
151 * on the filesystem.
152 */
153const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
154{
155 static char path[PATH_MAX];
156#ifndef WIN32
157 if (!pfx_len || is_absolute_path(arg))
158 return arg;
159 memcpy(path, pfx, pfx_len);
160 strcpy(path + pfx_len, arg);
161#else
162 char *p;
163 /* don't add prefix to absolute paths, but still replace '\' by '/' */
164 if (is_absolute_path(arg))
165 pfx_len = 0;
166 else if (pfx_len)
167 memcpy(path, pfx, pfx_len);
168 strcpy(path + pfx_len, arg);
169 for (p = path + pfx_len; *p; p++)
170 if (*p == '\\')
171 *p = '/';
172#endif
173 return path;
174}