From 55944e5e40b1be2afc4855d8d2baf4b73d1876b5 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 10 Apr 2024 22:49:52 +0200 Subject: Adding upstream version 255.4. Signed-off-by: Daniel Baumann --- src/shared/base-filesystem.c | 210 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 210 insertions(+) create mode 100644 src/shared/base-filesystem.c (limited to 'src/shared/base-filesystem.c') diff --git a/src/shared/base-filesystem.c b/src/shared/base-filesystem.c new file mode 100644 index 0000000..569ef46 --- /dev/null +++ b/src/shared/base-filesystem.c @@ -0,0 +1,210 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include +#include +#include +#include +#include +#include +#include + +#include "alloc-util.h" +#include "architecture.h" +#include "base-filesystem.h" +#include "errno-util.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", 0555, NULL, NULL, true }, + { "sys", 0555, NULL, NULL, true }, + { "dev", 0555, NULL, NULL, true }, + { "run", 0555, NULL, NULL, true }, + /* We don't add /tmp/ here for now (even though it's necessary for regular operation), because we + * want to support both cases where /tmp/ is a mount of its own (in which case we probably should set + * the mode to 1555, to indicate that no one should write to it, not even root) and when it's part of + * the rootfs (in which case we should set mode 1777), and we simply don't know what's right. */ + + /* 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 and Arch-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" + "usr/lib\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" + "usr/lib\0", "ld-linux-x86-64.so.2" }, +# define KNOW_LIB64_DIRS 1 +#elif defined(__ia64__) +#elif defined(__loongarch_lp64) +# define KNOW_LIB64_DIRS 1 +# if defined(__loongarch_double_float) + { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" + "usr/lib64\0" + "usr/lib\0", "ld-linux-loongarch-lp64d.so.1" }, +# elif defined(__loongarch_single_float) + { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" + "usr/lib64\0" + "usr/lib\0", "ld-linux-loongarch-lp64f.so.1" }, +# elif defined(__loongarch_soft_float) + { "lib64", 0, "usr/lib/"LIB_ARCH_TUPLE"\0" + "usr/lib64\0" + "usr/lib\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" + "usr/lib\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" + "usr/lib\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" + "usr/lib\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_fd(int fd, const char *root, uid_t uid, gid_t gid) { + int r; + + assert(fd >= 0); + assert(root); + + /* The "root" parameter is decoration only – it's only used as part of log messages */ + + 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) { /* Create as symlink? */ + const char *target = NULL; + + /* 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; + + r = RET_NERRNO(symlinkat(target, fd, table[i].dir)); + } else { + /* Create as directory. */ + WITH_UMASK(0000) + r = RET_NERRNO(mkdirat(fd, table[i].dir, table[i].mode)); + } + if (r < 0) { + bool ignore = IN_SET(r, -EEXIST, -EROFS) || table[i].ignore_failure; + log_full_errno(ignore ? LOG_DEBUG : LOG_ERR, r, + "Failed to create %s/%s: %m", root, table[i].dir); + if (ignore) + continue; + + return r; + } + + 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 %s/%s: %m", root, table[i].dir); + } + + return 0; +} + +int base_filesystem_create(const char *root, uid_t uid, gid_t gid) { + _cleanup_close_ int fd = -EBADF; + + fd = open(ASSERT_PTR(root), O_DIRECTORY|O_CLOEXEC); + if (fd < 0) + return log_error_errno(errno, "Failed to open root file system: %m"); + + return base_filesystem_create_fd(fd, root, uid, gid); +} -- cgit v1.2.3