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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
3577de7a KS |
2 | |
3 | #include <errno.h> | |
a8fbdf54 TA |
4 | #include <fcntl.h> |
5 | #include <stdbool.h> | |
3577de7a | 6 | #include <stdlib.h> |
07630cea | 7 | #include <sys/stat.h> |
a8fbdf54 | 8 | #include <syslog.h> |
3577de7a KS |
9 | #include <unistd.h> |
10 | ||
b5efdb8a | 11 | #include "alloc-util.h" |
a965a319 | 12 | #include "architecture.h" |
affb60b1 | 13 | #include "base-filesystem.h" |
9a22b098 | 14 | #include "errno-util.h" |
affb60b1 | 15 | #include "fd-util.h" |
3577de7a KS |
16 | #include "log.h" |
17 | #include "macro.h" | |
d8b4d14d | 18 | #include "nulstr-util.h" |
65290fbf | 19 | #include "path-util.h" |
07630cea | 20 | #include "string-util.h" |
affb60b1 | 21 | #include "umask-util.h" |
ee104e11 | 22 | #include "user-util.h" |
3577de7a KS |
23 | |
24 | typedef struct BaseFilesystem { | |
04ba1bb0 | 25 | const char *dir; /* directory or symlink to create */ |
3577de7a | 26 | mode_t mode; |
04ba1bb0 | 27 | const char *target; /* if non-NULL create as symlink to this target */ |
a6f44d61 | 28 | const char *exists; /* conditionalize this entry on existence of this file */ |
6404ecc8 | 29 | bool ignore_failure; |
3577de7a KS |
30 | } BaseFilesystem; |
31 | ||
32 | static const BaseFilesystem table[] = { | |
30d7c9c4 HH |
33 | { "bin", 0, "usr/bin\0", NULL }, |
34 | { "lib", 0, "usr/lib\0", NULL }, | |
93cbc9ca | 35 | { "root", 0750, NULL, NULL, true }, |
30d7c9c4 | 36 | { "sbin", 0, "usr/sbin\0", NULL }, |
03cfe0d5 LP |
37 | { "usr", 0755, NULL, NULL }, |
38 | { "var", 0755, NULL, NULL }, | |
39 | { "etc", 0755, NULL, NULL }, | |
7243cefe LP |
40 | { "proc", 0555, NULL, NULL, true }, |
41 | { "sys", 0555, NULL, NULL, true }, | |
42 | { "dev", 0555, NULL, NULL, true }, | |
6f32005f | 43 | |
04ba1bb0 LP |
44 | /* Various architecture ABIs define the path to the dynamic loader via the /lib64/ subdirectory of |
45 | * the root directory. When booting from an otherwise empty root file system (where only /usr/ has | |
46 | * been mounted into) it is thus necessary to create a symlink pointing to the right subdirectory of | |
47 | * /usr/ first — otherwise we couldn't invoke any dynamic binary. Let's detect this case here, and | |
48 | * create the symlink as needed should it be missing. We prefer doing this consistently with Debian's | |
27e69584 | 49 | * multiarch logic, but support Fedora-style and Arch-style multilib too. */ |
6f32005f | 50 | #if defined(__aarch64__) |
dcc87c68 ZJS |
51 | /* aarch64 ELF ABI actually says dynamic loader is in /lib/, but Fedora puts it in /lib64/ anyway and |
52 | * just symlinks /lib/ld-linux-aarch64.so.1 to ../lib64/ld-linux-aarch64.so.1. For this to work | |
53 | * correctly, /lib64/ must be symlinked to /usr/lib64/. */ | |
a965a319 | 54 | { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" |
27e69584 AV |
55 | "usr/lib64\0" |
56 | "usr/lib\0", "ld-linux-aarch64.so.1" }, | |
dcc87c68 | 57 | # define KNOW_LIB64_DIRS 1 |
6f32005f ZJS |
58 | #elif defined(__alpha__) |
59 | #elif defined(__arc__) || defined(__tilegx__) | |
60 | #elif defined(__arm__) | |
2db409ce ZJS |
61 | /* No /lib64 on arm. The linker is /lib/ld-linux-armhf.so.3. */ |
62 | # define KNOW_LIB64_DIRS 1 | |
6f32005f | 63 | #elif defined(__i386__) || defined(__x86_64__) |
a965a319 | 64 | { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" |
27e69584 AV |
65 | "usr/lib64\0" |
66 | "usr/lib\0", "ld-linux-x86-64.so.2" }, | |
6f32005f ZJS |
67 | # define KNOW_LIB64_DIRS 1 |
68 | #elif defined(__ia64__) | |
01722893 XW |
69 | #elif defined(__loongarch64) |
70 | # define KNOW_LIB64_DIRS 1 | |
71 | # if defined(__loongarch_double_float) | |
72 | { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" | |
27e69584 AV |
73 | "usr/lib64\0" |
74 | "usr/lib\0", "ld-linux-loongarch-lp64d.so.1" }, | |
01722893 XW |
75 | # elif defined(__loongarch_single_float) |
76 | { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" | |
27e69584 AV |
77 | "usr/lib64\0" |
78 | "usr/lib\0", "ld-linux-loongarch-lp64f.so.1" }, | |
01722893 XW |
79 | # elif defined(__loongarch_soft_float) |
80 | { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" | |
27e69584 AV |
81 | "usr/lib64\0" |
82 | "usr/lib\0", "ld-linux-loongarch-lp64s.so.1" }, | |
01722893 XW |
83 | # else |
84 | # error "Unknown LoongArch ABI" | |
85 | # endif | |
6f32005f | 86 | #elif defined(__m68k__) |
996eaea5 ZJS |
87 | /* No link needed. */ |
88 | # define KNOW_LIB64_DIRS 1 | |
6f32005f ZJS |
89 | #elif defined(_MIPS_SIM) |
90 | # if _MIPS_SIM == _MIPS_SIM_ABI32 | |
91 | # elif _MIPS_SIM == _MIPS_SIM_NABI32 | |
92 | # elif _MIPS_SIM == _MIPS_SIM_ABI64 | |
93 | # else | |
94 | # error "Unknown MIPS ABI" | |
95 | # endif | |
96 | #elif defined(__powerpc__) | |
e98157b9 | 97 | # if defined(__PPC64__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ |
a965a319 | 98 | { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" |
27e69584 AV |
99 | "usr/lib64\0" |
100 | "usr/lib\0", "ld64.so.2" }, | |
e98157b9 ZJS |
101 | # define KNOW_LIB64_DIRS 1 |
102 | # elif defined(__powerpc64__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ | |
103 | /* powerpc64-linux-gnu */ | |
104 | # else | |
105 | /* powerpc-linux-gnu */ | |
106 | # endif | |
6f32005f ZJS |
107 | #elif defined(__riscv) |
108 | # if __riscv_xlen == 32 | |
109 | # elif __riscv_xlen == 64 | |
761e9382 | 110 | /* Same situation as for aarch64 */ |
a965a319 | 111 | { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" |
27e69584 AV |
112 | "usr/lib64\0" |
113 | "usr/lib\0", "ld-linux-riscv64-lp64d.so.1" }, | |
761e9382 | 114 | # define KNOW_LIB64_DIRS 1 |
6f32005f ZJS |
115 | # else |
116 | # error "Unknown RISC-V ABI" | |
117 | # endif | |
118 | #elif defined(__s390__) | |
fe037986 | 119 | /* s390-linux-gnu */ |
6f32005f | 120 | #elif defined(__s390x__) |
a965a319 | 121 | { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" |
27e69584 AV |
122 | "usr/lib64\0" |
123 | "usr/lib\0", "ld-lsb-s390x.so.3" }, | |
fe037986 | 124 | # define KNOW_LIB64_DIRS 1 |
6f32005f | 125 | #elif defined(__sparc__) |
e1ae9755 | 126 | #endif |
6f32005f | 127 | /* gcc doesn't allow pragma to be used within constructs, hence log about this separately below */ |
3577de7a KS |
128 | }; |
129 | ||
6f32005f ZJS |
130 | #ifndef KNOW_LIB64_DIRS |
131 | # pragma message "Please add an entry above specifying whether your architecture uses /lib64/, /lib32/, or no such links." | |
04ba1bb0 LP |
132 | #endif |
133 | ||
8aefedce | 134 | int base_filesystem_create_fd(int fd, const char *root, uid_t uid, gid_t gid) { |
8a383bf2 | 135 | int r; |
3577de7a | 136 | |
8aefedce LP |
137 | assert(fd >= 0); |
138 | assert(root); | |
139 | ||
140 | /* The "root" parameter is decoration only – it's only used as part of log messages */ | |
3577de7a | 141 | |
9b4aba10 | 142 | for (size_t i = 0; i < ELEMENTSOF(table); i++) { |
6f4f8056 HH |
143 | if (faccessat(fd, table[i].dir, F_OK, AT_SYMLINK_NOFOLLOW) >= 0) |
144 | continue; | |
145 | ||
9a22b098 | 146 | if (table[i].target) { /* Create as symlink? */ |
12e2b70f | 147 | const char *target = NULL; |
e1ae9755 KS |
148 | |
149 | /* check if one of the targets exists */ | |
150 | NULSTR_FOREACH(s, table[i].target) { | |
151 | if (faccessat(fd, s, F_OK, AT_SYMLINK_NOFOLLOW) < 0) | |
152 | continue; | |
153 | ||
3fd165e5 KS |
154 | /* check if a specific file exists at the target path */ |
155 | if (table[i].exists) { | |
156 | _cleanup_free_ char *p = NULL; | |
157 | ||
65290fbf | 158 | p = path_join(s, table[i].exists); |
3fd165e5 KS |
159 | if (!p) |
160 | return log_oom(); | |
161 | ||
162 | if (faccessat(fd, p, F_OK, AT_SYMLINK_NOFOLLOW) < 0) | |
163 | continue; | |
164 | } | |
165 | ||
e1ae9755 KS |
166 | target = s; |
167 | break; | |
168 | } | |
169 | ||
170 | if (!target) | |
3577de7a KS |
171 | continue; |
172 | ||
9a22b098 LP |
173 | r = RET_NERRNO(symlinkat(target, fd, table[i].dir)); |
174 | } else { | |
175 | /* Create as directory. */ | |
176 | WITH_UMASK(0000) | |
177 | r = RET_NERRNO(mkdirat(fd, table[i].dir, table[i].mode)); | |
3577de7a | 178 | } |
8258578f | 179 | if (r < 0) { |
9a22b098 LP |
180 | bool ignore = IN_SET(r, -EEXIST, -EROFS) || table[i].ignore_failure; |
181 | log_full_errno(ignore ? LOG_DEBUG : LOG_ERR, r, | |
182 | "Failed to create %s/%s: %m", root, table[i].dir); | |
183 | if (ignore) | |
8258578f | 184 | continue; |
d1d59eeb | 185 | |
9a22b098 | 186 | return r; |
6404ecc8 | 187 | } |
03cfe0d5 | 188 | |
264caae2 | 189 | if (uid_is_valid(uid) || gid_is_valid(gid)) |
03cfe0d5 | 190 | if (fchownat(fd, table[i].dir, uid, gid, AT_SYMLINK_NOFOLLOW) < 0) |
9a22b098 | 191 | return log_error_errno(errno, "Failed to chown %s/%s: %m", root, table[i].dir); |
3577de7a KS |
192 | } |
193 | ||
194 | return 0; | |
195 | } | |
8aefedce LP |
196 | |
197 | int base_filesystem_create(const char *root, uid_t uid, gid_t gid) { | |
198 | _cleanup_close_ int fd = -EBADF; | |
199 | ||
200 | fd = open(ASSERT_PTR(root), O_DIRECTORY|O_CLOEXEC); | |
201 | if (fd < 0) | |
202 | return log_error_errno(errno, "Failed to open root file system: %m"); | |
203 | ||
204 | return base_filesystem_create_fd(fd, root, uid, gid); | |
205 | } |