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
|
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <syslog.h>
#include <unistd.h>
#include "alloc-util.h"
#include "architecture.h"
#include "base-filesystem.h"
#include "fd-util.h"
#include "log.h"
#include "macro.h"
#include "nulstr-util.h"
#include "path-util.h"
#include "string-util.h"
#include "umask-util.h"
#include "user-util.h"
typedef struct BaseFilesystem {
const char *dir; /* directory or symlink to create */
mode_t mode;
const char *target; /* if non-NULL create as symlink to this target */
const char *exists; /* conditionalize this entry on existence of this file */
bool ignore_failure;
} BaseFilesystem;
static const BaseFilesystem table[] = {
{ "bin", 0, "usr/bin\0", NULL },
{ "lib", 0, "usr/lib\0", NULL },
{ "root", 0750, NULL, NULL, true },
{ "sbin", 0, "usr/sbin\0", NULL },
{ "usr", 0755, NULL, NULL },
{ "var", 0755, NULL, NULL },
{ "etc", 0755, NULL, NULL },
{ "proc", 0755, NULL, NULL, true },
{ "sys", 0755, NULL, NULL, true },
{ "dev", 0755, NULL, NULL, true },
/* Various architecture ABIs define the path to the dynamic loader via the /lib64/ subdirectory of
* the root directory. When booting from an otherwise empty root file system (where only /usr/ has
* been mounted into) it is thus necessary to create a symlink pointing to the right subdirectory of
* /usr/ first — otherwise we couldn't invoke any dynamic binary. Let's detect this case here, and
* create the symlink as needed should it be missing. We prefer doing this consistently with Debian's
* multiarch logic, but support Fedora-style multilib too.*/
#if defined(__aarch64__)
/* aarch64 ELF ABI actually says dynamic loader is in /lib/, but Fedora puts it in /lib64/ anyway and
* just symlinks /lib/ld-linux-aarch64.so.1 to ../lib64/ld-linux-aarch64.so.1. For this to work
* correctly, /lib64/ must be symlinked to /usr/lib64/. */
{ "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0"
"usr/lib64\0", "ld-linux-aarch64.so.1" },
# define KNOW_LIB64_DIRS 1
#elif defined(__alpha__)
#elif defined(__arc__) || defined(__tilegx__)
#elif defined(__arm__)
/* No /lib64 on arm. The linker is /lib/ld-linux-armhf.so.3. */
# define KNOW_LIB64_DIRS 1
#elif defined(__i386__) || defined(__x86_64__)
{ "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0"
"usr/lib64\0", "ld-linux-x86-64.so.2" },
# define KNOW_LIB64_DIRS 1
#elif defined(__ia64__)
#elif defined(__loongarch64)
# define KNOW_LIB64_DIRS 1
# if defined(__loongarch_double_float)
{ "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0"
"usr/lib64\0", "ld-linux-loongarch-lp64d.so.1" },
# elif defined(__loongarch_single_float)
{ "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0"
"usr/lib64\0", "ld-linux-loongarch-lp64f.so.1" },
# elif defined(__loongarch_soft_float)
{ "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0"
"usr/lib64\0", "ld-linux-loongarch-lp64s.so.1" },
# else
# error "Unknown LoongArch ABI"
# endif
#elif defined(__m68k__)
/* No link needed. */
# define KNOW_LIB64_DIRS 1
#elif defined(_MIPS_SIM)
# if _MIPS_SIM == _MIPS_SIM_ABI32
# elif _MIPS_SIM == _MIPS_SIM_NABI32
# elif _MIPS_SIM == _MIPS_SIM_ABI64
# else
# error "Unknown MIPS ABI"
# endif
#elif defined(__powerpc__)
# if defined(__PPC64__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
{ "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0"
"usr/lib64\0", "ld64.so.2" },
# define KNOW_LIB64_DIRS 1
# elif defined(__powerpc64__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
/* powerpc64-linux-gnu */
# else
/* powerpc-linux-gnu */
# endif
#elif defined(__riscv)
# if __riscv_xlen == 32
# elif __riscv_xlen == 64
/* Same situation as for aarch64 */
{ "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0"
"usr/lib64\0", "ld-linux-riscv64-lp64d.so.1" },
# define KNOW_LIB64_DIRS 1
# else
# error "Unknown RISC-V ABI"
# endif
#elif defined(__s390__)
/* s390-linux-gnu */
#elif defined(__s390x__)
{ "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0"
"usr/lib64\0", "ld-lsb-s390x.so.3" },
# define KNOW_LIB64_DIRS 1
#elif defined(__sparc__)
#endif
/* gcc doesn't allow pragma to be used within constructs, hence log about this separately below */
};
#ifndef KNOW_LIB64_DIRS
# pragma message "Please add an entry above specifying whether your architecture uses /lib64/, /lib32/, or no such links."
#endif
int base_filesystem_create(const char *root, uid_t uid, gid_t gid) {
_cleanup_close_ int fd = -1;
int r;
fd = open(root, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW);
if (fd < 0)
return log_error_errno(errno, "Failed to open root file system: %m");
for (size_t i = 0; i < ELEMENTSOF(table); i++) {
if (faccessat(fd, table[i].dir, F_OK, AT_SYMLINK_NOFOLLOW) >= 0)
continue;
if (table[i].target) {
const char *target = NULL, *s;
/* check if one of the targets exists */
NULSTR_FOREACH(s, table[i].target) {
if (faccessat(fd, s, F_OK, AT_SYMLINK_NOFOLLOW) < 0)
continue;
/* check if a specific file exists at the target path */
if (table[i].exists) {
_cleanup_free_ char *p = NULL;
p = path_join(s, table[i].exists);
if (!p)
return log_oom();
if (faccessat(fd, p, F_OK, AT_SYMLINK_NOFOLLOW) < 0)
continue;
}
target = s;
break;
}
if (!target)
continue;
if (symlinkat(target, fd, table[i].dir) < 0) {
log_full_errno(IN_SET(errno, EEXIST, EROFS) || table[i].ignore_failure ? LOG_DEBUG : LOG_ERR, errno,
"Failed to create symlink at %s/%s: %m", root, table[i].dir);
if (IN_SET(errno, EEXIST, EROFS) || table[i].ignore_failure)
continue;
return -errno;
}
if (uid_is_valid(uid) || gid_is_valid(gid))
if (fchownat(fd, table[i].dir, uid, gid, AT_SYMLINK_NOFOLLOW) < 0)
return log_error_errno(errno, "Failed to chown symlink at %s/%s: %m", root, table[i].dir);
continue;
}
RUN_WITH_UMASK(0000)
r = mkdirat(fd, table[i].dir, table[i].mode);
if (r < 0) {
log_full_errno(IN_SET(errno, EEXIST, EROFS) || table[i].ignore_failure ? LOG_DEBUG : LOG_ERR, errno,
"Failed to create directory at %s/%s: %m", root, table[i].dir);
if (IN_SET(errno, EEXIST, EROFS) || table[i].ignore_failure)
continue;
return -errno;
}
if (uid_is_valid(uid) || gid_is_valid(gid))
if (fchownat(fd, table[i].dir, uid, gid, AT_SYMLINK_NOFOLLOW) < 0)
return log_error_errno(errno, "Failed to chown directory at %s/%s: %m", root, table[i].dir);
}
return 0;
}
|
