1 /* mkdir-p.c -- Ensure that a directory and its parents exist.
2
3 Copyright (C) 1990, 1997-2000, 2002-2007, 2009-2023 Free Software
4 Foundation, Inc.
5
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <https://www.gnu.org/licenses/>. */
18
19 /* Written by Paul Eggert, David MacKenzie, and Jim Meyering. */
20
21 #include <config.h>
22
23 #include "mkdir-p.h"
24
25 #include <errno.h>
26 #include <sys/stat.h>
27 #include <unistd.h>
28
29 #include "gettext.h"
30 #define _(msgid) gettext (msgid)
31
32 #include "dirchownmod.h"
33 #include "dirname.h"
34 #include "error.h"
35 #include "quote.h"
36 #include "mkancesdirs.h"
37 #include "savewd.h"
38
39 #ifndef HAVE_FCHMOD
40 # define HAVE_FCHMOD false
41 #endif
42
43 /* Ensure that the directory DIR exists.
44
45 WD is the working directory, as in savewd.c.
46
47 If MAKE_ANCESTOR is not null, create any ancestor directories that
48 don't already exist, by invoking MAKE_ANCESTOR (DIR, ANCESTOR, OPTIONS).
49 This function should return zero if successful, -1 (setting errno)
50 otherwise. In this case, DIR may be modified by storing '\0' bytes
51 into it, to access the ancestor directories, and this modification
52 is retained on return if the ancestor directories could not be
53 created.
54
55 Create DIR as a new directory, using mkdir with permissions MODE;
56 here, MODE is affected by the umask in the usual way. It is also
57 OK if MAKE_ANCESTOR is not null and a directory DIR already exists.
58
59 Call ANNOUNCE (DIR, OPTIONS) just after successfully making DIR,
60 even if some of the following actions fail.
61
62 Set DIR's owner to OWNER and group to GROUP, but leave the owner
63 alone if OWNER is (uid_t) -1, and similarly for GROUP.
64
65 Set DIR's mode bits to MODE, except preserve any of the bits that
66 correspond to zero bits in MODE_BITS. In other words, MODE_BITS is
67 a mask that specifies which of DIR's mode bits should be set or
68 cleared. Changing the mode in this way is necessary if DIR already
69 existed, if MODE and MODE_BITS specify non-permissions bits like
70 S_ISUID, or if MODE and MODE_BITS specify permissions bits that are
71 masked out by the umask. MODE_BITS should be a subset of
72 CHMOD_MODE_BITS.
73
74 However, if PRESERVE_EXISTING is true and DIR already exists,
75 do not attempt to set DIR's ownership and file mode bits.
76
77 Return true if DIR exists as a directory with the proper ownership
78 and file mode bits when done, or if a child process has been
79 dispatched to do the real work (though the child process may not
80 have finished yet -- it is the caller's responsibility to handle
81 this). Report a diagnostic and return false on failure, storing
82 '\0' into *DIR if an ancestor directory had problems. */
83
84 bool
85 make_dir_parents (char *dir,
86 struct savewd *wd,
87 int (*make_ancestor) (char const *, char const *, void *),
88 void *options,
89 mode_t mode,
90 void (*announce) (char const *, void *),
91 mode_t mode_bits,
92 uid_t owner,
93 gid_t group,
94 bool preserve_existing)
95 {
96 int mkdir_errno = (IS_ABSOLUTE_FILE_NAME (dir) ? 0 : savewd_errno (wd));
97
98 if (mkdir_errno == 0)
99 {
100 ptrdiff_t prefix_len = 0;
101 int savewd_chdir_options = (HAVE_FCHMOD ? SAVEWD_CHDIR_SKIP_READABLE : 0);
102
103 if (make_ancestor)
104 {
105 prefix_len = mkancesdirs (dir, wd, make_ancestor, options);
106 if (prefix_len < 0)
107 {
108 if (prefix_len < -1)
109 return true;
110 mkdir_errno = errno;
111 }
112 }
113
114 if (0 <= prefix_len)
115 {
116 /* If the ownership might change, or if the directory will be
117 writable to other users and its special mode bits may
118 change after the directory is created, create it with
119 more restrictive permissions at first, so unauthorized
120 users cannot nip in before the directory is ready. */
121 bool keep_owner = owner == (uid_t) -1 && group == (gid_t) -1;
122 bool keep_special_mode_bits =
123 ((mode_bits & (S_ISUID | S_ISGID)) | (mode & S_ISVTX)) == 0;
124 mode_t mkdir_mode = mode;
125 if (! keep_owner)
126 mkdir_mode &= ~ (S_IRWXG | S_IRWXO);
127 else if (! keep_special_mode_bits)
128 mkdir_mode &= ~ (S_IWGRP | S_IWOTH);
129
130 if (mkdir (dir + prefix_len, mkdir_mode) == 0)
131 {
132 /* True if the caller does not care about the umask's
133 effect on the permissions. */
134 bool umask_must_be_ok = (mode & mode_bits & S_IRWXUGO) == 0;
135
136 announce (dir, options);
137 preserve_existing = (keep_owner & keep_special_mode_bits
138 & umask_must_be_ok);
139 savewd_chdir_options |= SAVEWD_CHDIR_NOFOLLOW;
140 }
141 else
142 {
143 mkdir_errno = errno;
144 mkdir_mode = -1;
145 }
146
147 if (preserve_existing)
148 {
149 if (mkdir_errno == 0)
150 return true;
151 if (mkdir_errno != ENOENT && make_ancestor)
152 {
153 struct stat st;
154 if (stat (dir + prefix_len, &st) == 0)
155 {
156 if (S_ISDIR (st.st_mode))
157 return true;
158 }
159 else if (mkdir_errno == EEXIST
160 && errno != ENOENT && errno != ENOTDIR)
161 {
162 error (0, errno, _("cannot stat %s"), quote (dir));
163 return false;
164 }
165 }
166 }
167 else
168 {
169 int open_result[2];
170 int chdir_result =
171 savewd_chdir (wd, dir + prefix_len,
172 savewd_chdir_options, open_result);
173 if (chdir_result < -1)
174 return true;
175 else
176 {
177 bool chdir_ok = (chdir_result == 0);
178 char const *subdir = (chdir_ok ? "." : dir + prefix_len);
179 if (dirchownmod (open_result[0], subdir, mkdir_mode,
180 owner, group, mode, mode_bits)
181 == 0)
182 return true;
183
184 if (mkdir_errno == 0
185 || (mkdir_errno != ENOENT && make_ancestor
186 && errno != ENOTDIR))
187 {
188 error (0, errno,
189 _(keep_owner
190 ? "cannot change permissions of %s"
191 : "cannot change owner and permissions of %s"),
192 quote (dir));
193 return false;
194 }
195 }
196 }
197 }
198 }
199
200 error (0, mkdir_errno, _("cannot create directory %s"), quote (dir));
201 return false;
202 }