]> git.ipfire.org Git - thirdparty/systemd.git/blobdiff - src/shared/base-filesystem.c
nulstr-util: Declare NULSTR_FOREACH() iterator inline
[thirdparty/systemd.git] / src / shared / base-filesystem.c
index 657407da2d3794661f96cbf71c00f8f919f154f9..c2902d35082e40b9d26a69269a64e634885ae518 100644 (file)
@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: LGPL-2.1+ */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <errno.h>
 #include <fcntl.h>
@@ -9,6 +9,7 @@
 #include <unistd.h>
 
 #include "alloc-util.h"
+#include "architecture.h"
 #include "base-filesystem.h"
 #include "fd-util.h"
 #include "log.h"
 #include "user-util.h"
 
 typedef struct BaseFilesystem {
-        const char *dir;
+        const char *dir;      /* directory or symlink to create */
         mode_t mode;
-        const char *target;
-        const char *exists;
+        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",  0755, NULL,                         NULL, true },
+        { "root",  0750, NULL,                         NULL, true },
         { "sbin",     0, "usr/sbin\0",                 NULL },
         { "usr",   0755, NULL,                         NULL },
         { "var",   0755, NULL,                         NULL },
@@ -38,27 +39,103 @@ static const BaseFilesystem table[] = {
         { "proc",  0755, NULL,                         NULL, true },
         { "sys",   0755, NULL,                         NULL, true },
         { "dev",   0755, NULL,                         NULL, true },
-#if defined(__i386__) || defined(__x86_64__)
-        { "lib64",    0, "usr/lib/x86_64-linux-gnu\0"
+
+        /* 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;
-        size_t i;
         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 (i = 0; i < ELEMENTSOF(table); i ++) {
+        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;
+                        const char *target = NULL;
 
                         /* check if one of the targets exists */
                         NULSTR_FOREACH(s, table[i].target) {
@@ -94,10 +171,9 @@ int base_filesystem_create(const char *root, uid_t uid, gid_t gid) {
                                 return -errno;
                         }
 
-                        if (uid_is_valid(uid) || gid_is_valid(gid)) {
+                        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;
                 }
@@ -114,10 +190,9 @@ int base_filesystem_create(const char *root, uid_t uid, gid_t gid) {
                         return -errno;
                 }
 
-                if (uid != UID_INVALID || gid != UID_INVALID) {
+                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;