# SOME DESCRIPTIVE TITLE # Copyright (C) YEAR Free Software Foundation, Inc. # This file is distributed under the same license as the PACKAGE package. # FIRST AUTHOR , YEAR. # #, fuzzy msgid "" msgstr "" "Project-Id-Version: PACKAGE VERSION\n" "POT-Creation-Date: 2024-06-01 06:09+0200\n" "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n" "Last-Translator: FULL NAME \n" "Language-Team: LANGUAGE \n" "Language: \n" "MIME-Version: 1.0\n" "Content-Type: text/plain; charset=UTF-8\n" "Content-Transfer-Encoding: 8bit\n" #. type: TH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "pivot_root" msgstr "" #. type: TH #: archlinux debian-unstable opensuse-tumbleweed #, no-wrap msgid "2024-05-02" msgstr "" #. type: TH #: archlinux debian-unstable #, no-wrap msgid "Linux man-pages 6.8" msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "NAME" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "pivot_root - change the root mount" msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "LIBRARY" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "Standard C library (I, I<-lc>)" msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "SYNOPSIS" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "" "B<#include Esys/syscall.hE> /* Definition of B constants */\n" "B<#include Eunistd.hE>\n" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "BIB<, const char *>IB<);>\n" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "I: glibc provides no wrapper for B(), necessitating the " "use of B(2)." msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "DESCRIPTION" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "B() changes the root mount in the mount namespace of the " "calling process. More precisely, it moves the root mount to the directory " "I and makes I the new root mount. The calling process " "must have the B capability in the user namespace that owns " "the caller's mount namespace." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "B() changes the root directory and the current working " "directory of each process or thread in the same mount namespace to " "I if they point to the old root directory. (See also NOTES.) On " "the other hand, B() does not change the caller's current " "working directory (unless it is on the old root directory), and thus it " "should be followed by a B call." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "The following restrictions apply:" msgstr "" #. type: IP #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "\\[bu]" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "I and I must be directories." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "I and I must not be on the same mount as the current root." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "I must be at or underneath I; that is, adding some " "nonnegative number of \"I\" suffixes to the pathname pointed to by " "I must yield the same directory as I." msgstr "" #. type: Plain text #: archlinux debian-unstable fedora-rawhide opensuse-tumbleweed msgid "" "I must be a path to a mount point, but can't be I<\\[dq]/\\[dq]>. " "A path that is not already a mount point can be converted into one by bind " "mounting the path onto itself." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "The propagation type of the parent mount of I and the parent mount " "of the current root directory must not be B; similarly, if " "I is an existing mount point, its propagation type must not be " "B. These restrictions ensure that B() never " "propagates any changes to another mount namespace." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "The current root directory must be a mount point." msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "RETURN VALUE" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "On success, zero is returned. On error, -1 is returned, and I is set " "to indicate the error." msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "ERRORS" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "B() may fail with any of the same errors as B(2). " "Additionally, it may fail with the following errors:" msgstr "" #. type: TP #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "B" msgstr "" #. Reconfirmed that the following error occurs on Linux 5.0 by #. specifying 'new_root' as "/rootfs" and 'put_old' as #. "/rootfs/oldrootfs", and *not* bind mounting "/rootfs" on top of #. itself. Of course, this is an odd situation, since a later check #. in the kernel code will in any case yield EINVAL if 'new_root' is #. not a mount point. However, when the system call was first added, #. 'new_root' was not required to be a mount point. So, this #. error is nowadays probably just the result of crufty accumulation. #. This error can also occur if we bind mount "/" on top of itself #. and try to specify "/" as the 'new' (again, an odd situation). So, #. the EBUSY check in the kernel does still seem necessary to prevent #. that case. Furthermore, the "or put_old" piece is probably #. redundant text (although the check is in the kernel), since, #. in another check, 'put_old' is required to be under 'new_root'. #. type: Plain text #: archlinux debian-unstable fedora-rawhide opensuse-tumbleweed msgid "" "I or I is on the current root mount. (This error covers " "the pathological case where I is I<\\[dq]/\\[dq]>.)" msgstr "" #. type: TP #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "B" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "I is not a mount point." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "I is not at or underneath I." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "The current root directory is not a mount point (because of an earlier " "B(2))." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "The current root is on the rootfs (initial ramfs) mount; see NOTES." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "Either the mount point at I, or the parent mount of that mount " "point, has propagation type B." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "I is a mount point and has the propagation type B." msgstr "" #. type: TP #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "B" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "I or I is not a directory." msgstr "" #. type: TP #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "B" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "The calling process does not have the B capability." msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "STANDARDS" msgstr "" #. type: Plain text #: archlinux debian-unstable fedora-40 fedora-rawhide mageia-cauldron #: opensuse-leap-15-6 opensuse-tumbleweed msgid "Linux." msgstr "" #. type: SH #: archlinux debian-unstable fedora-40 fedora-rawhide mageia-cauldron #: opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "HISTORY" msgstr "" #. type: Plain text #: archlinux debian-unstable fedora-40 fedora-rawhide mageia-cauldron #: opensuse-leap-15-6 opensuse-tumbleweed msgid "Linux 2.3.41." msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "NOTES" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "A command-line interface for this system call is provided by " "B(8)." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "B() allows the caller to switch to a new root filesystem while " "at the same time placing the old root mount at a location under I " "from where it can subsequently be unmounted. (The fact that it moves all " "processes that have a root directory or current working directory on the old " "root directory to the new root frees the old root directory of users, " "allowing the old root mount to be unmounted more easily.)" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "One use of B() is during system startup, when the system mounts " "a temporary root filesystem (e.g., an B(4)), then mounts the real " "root filesystem, and eventually turns the latter into the root directory of " "all relevant processes and threads. A modern use is to set up a root " "filesystem during the creation of a container." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "The fact that B() modifies process root and current working " "directories in the manner noted in DESCRIPTION is necessary in order to " "prevent kernel threads from keeping the old root mount busy with their root " "and current working directories, even if they never access the filesystem in " "any way." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "The rootfs (initial ramfs) cannot be B()ed. The recommended " "method of changing the root filesystem in this case is to delete everything " "in rootfs, overmount rootfs with the new root, attach I/I/" "I to the new I, and exec the new B(1). Helper " "programs for this process exist; see B(8)." msgstr "" #. type: SS #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "pivot_root(\\[dq].\\[dq], \\[dq].\\[dq])" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "I and I may be the same directory. In particular, the " "following sequence allows a pivot-root operation without needing to create " "and remove a temporary directory:" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "" "chdir(new_root);\n" "pivot_root(\".\", \".\");\n" "umount2(\".\", MNT_DETACH);\n" msgstr "" #. type: Plain text #: archlinux debian-unstable fedora-rawhide opensuse-tumbleweed msgid "" "This sequence succeeds because the B() call stacks the old root " "mount point on top of the new root mount point at I. At that point, the " "calling process's root directory and current working directory refer to the " "new root mount point (I). During the subsequent B() " "call, resolution of I<\\[dq].\\[dq]> starts with I and then moves " "up the list of mounts stacked at I, with the result that old root mount " "point is unmounted." msgstr "" #. type: SS #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "Historical notes" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "For many years, this manual page carried the following text:" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "B() may or may not change the current root and the current " "working directory of any processes or threads which use the old root " "directory. The caller of B() must ensure that processes with " "root or current working directory at the old root operate correctly in " "either case. An easy way to ensure this is to change their root and current " "working directory to I before invoking B()." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "This text, written before the system call implementation was even finalized " "in the kernel, was probably intended to warn users at that time that the " "implementation might change before final release. However, the behavior " "stated in DESCRIPTION has remained consistent since this system call was " "first implemented and will not change now." msgstr "" #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "EXAMPLES" msgstr "" #. FIXME #. Would it be better, because simpler, to use unshare(2) #. rather than clone(2) in the example below? #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "The program below demonstrates the use of B() inside a mount " "namespace that is created using B(2). After pivoting to the root " "directory named in the program's first command-line argument, the child " "created by B(2) then executes the program named in the remaining " "command-line arguments." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "We demonstrate the program by creating a directory that will serve as the " "new root filesystem and placing a copy of the (statically linked) " "B(1) executable in that directory." msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "" "$ B\n" "$ B # Show inode number of new root directory\n" "319459 /tmp/rootfs\n" "$ B\n" "$ B\n" "bbsh$ B\n" "bbsh$ B\n" "bbsh$ B\n" "bbsh$ B\n" "bbsh$ B\n" "busybox echo ln ls\n" "bbsh$ B # Compare with inode number above\n" "319459 /\n" "bbsh$ B\n" "hello world\n" msgstr "" #. type: SS #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "Program source" msgstr "" #. type: Plain text #: archlinux debian-unstable fedora-40 fedora-rawhide mageia-cauldron #: opensuse-tumbleweed #, no-wrap msgid "" "/* pivot_root_demo.c */\n" "\\&\n" "#define _GNU_SOURCE\n" "#include Eerr.hE\n" "#include Elimits.hE\n" "#include Esched.hE\n" "#include Esignal.hE\n" "#include Estdio.hE\n" "#include Estdlib.hE\n" "#include Esys/mman.hE\n" "#include Esys/mount.hE\n" "#include Esys/stat.hE\n" "#include Esys/syscall.hE\n" "#include Esys/wait.hE\n" "#include Eunistd.hE\n" "\\&\n" "static int\n" "pivot_root(const char *new_root, const char *put_old)\n" "{\n" " return syscall(SYS_pivot_root, new_root, put_old);\n" "}\n" "\\&\n" "#define STACK_SIZE (1024 * 1024)\n" "\\&\n" "static int /* Startup function for cloned child */\n" "child(void *arg)\n" "{\n" " char path[PATH_MAX];\n" " char **args = arg;\n" " char *new_root = args[0];\n" " const char *put_old = \"/oldrootfs\";\n" "\\&\n" " /* Ensure that \\[aq]new_root\\[aq] and its parent mount don\\[aq]t have\n" " shared propagation (which would cause pivot_root() to\n" " return an error), and prevent propagation of mount\n" " events to the initial mount namespace. */\n" "\\&\n" " if (mount(NULL, \"/\", NULL, MS_REC | MS_PRIVATE, NULL) == -1)\n" " err(EXIT_FAILURE, \"mount-MS_PRIVATE\");\n" "\\&\n" " /* Ensure that \\[aq]new_root\\[aq] is a mount point. */\n" "\\&\n" " if (mount(new_root, new_root, NULL, MS_BIND, NULL) == -1)\n" " err(EXIT_FAILURE, \"mount-MS_BIND\");\n" "\\&\n" " /* Create directory to which old root will be pivoted. */\n" "\\&\n" " snprintf(path, sizeof(path), \"%s/%s\", new_root, put_old);\n" " if (mkdir(path, 0777) == -1)\n" " err(EXIT_FAILURE, \"mkdir\");\n" "\\&\n" " /* And pivot the root filesystem. */\n" "\\&\n" " if (pivot_root(new_root, path) == -1)\n" " err(EXIT_FAILURE, \"pivot_root\");\n" "\\&\n" " /* Switch the current working directory to \"/\". */\n" "\\&\n" " if (chdir(\"/\") == -1)\n" " err(EXIT_FAILURE, \"chdir\");\n" "\\&\n" " /* Unmount old root and remove mount point. */\n" "\\&\n" " if (umount2(put_old, MNT_DETACH) == -1)\n" " perror(\"umount2\");\n" " if (rmdir(put_old) == -1)\n" " perror(\"rmdir\");\n" "\\&\n" " /* Execute the command specified in argv[1]... */\n" "\\&\n" " execv(args[1], &args[1]);\n" " err(EXIT_FAILURE, \"execv\");\n" "}\n" "\\&\n" "int\n" "main(int argc, char *argv[])\n" "{\n" " char *stack;\n" "\\&\n" " /* Create a child process in a new mount namespace. */\n" "\\&\n" " stack = mmap(NULL, STACK_SIZE, PROT_READ | PROT_WRITE,\n" " MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);\n" " if (stack == MAP_FAILED)\n" " err(EXIT_FAILURE, \"mmap\");\n" "\\&\n" " if (clone(child, stack + STACK_SIZE,\n" " CLONE_NEWNS | SIGCHLD, &argv[1]) == -1)\n" " err(EXIT_FAILURE, \"clone\");\n" "\\&\n" " /* Parent falls through to here; wait for child. */\n" "\\&\n" " if (wait(NULL) == -1)\n" " err(EXIT_FAILURE, \"wait\");\n" "\\&\n" " exit(EXIT_SUCCESS);\n" "}\n" msgstr "" #. SRC END #. type: SH #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed #, no-wrap msgid "SEE ALSO" msgstr "" #. type: Plain text #: archlinux debian-bookworm debian-unstable fedora-40 fedora-rawhide #: mageia-cauldron opensuse-leap-15-6 opensuse-tumbleweed msgid "" "B(2), B(2), B(2), B(2), B(4), " "B(7), B(8), B(8)" msgstr "" #. type: TH #: debian-bookworm #, no-wrap msgid "2023-02-05" msgstr "" #. type: TH #: debian-bookworm #, no-wrap msgid "Linux man-pages 6.03" msgstr "" #. type: Plain text #: debian-bookworm fedora-40 mageia-cauldron opensuse-leap-15-6 msgid "" "I must be a path to a mount point, but can't be I<\"/\">. A path " "that is not already a mount point can be converted into one by bind mounting " "the path onto itself." msgstr "" #. Reconfirmed that the following error occurs on Linux 5.0 by #. specifying 'new_root' as "/rootfs" and 'put_old' as #. "/rootfs/oldrootfs", and *not* bind mounting "/rootfs" on top of #. itself. Of course, this is an odd situation, since a later check #. in the kernel code will in any case yield EINVAL if 'new_root' is #. not a mount point. However, when the system call was first added, #. 'new_root' was not required to be a mount point. So, this #. error is nowadays probably just the result of crufty accumulation. #. This error can also occur if we bind mount "/" on top of itself #. and try to specify "/" as the 'new' (again, an odd situation). So, #. the EBUSY check in the kernel does still seem necessary to prevent #. that case. Furthermore, the "or put_old" piece is probably #. redundant text (although the check is in the kernel), since, #. in another check, 'put_old' is required to be under 'new_root'. #. type: Plain text #: debian-bookworm fedora-40 mageia-cauldron opensuse-leap-15-6 msgid "" "I or I is on the current root mount. (This error covers " "the pathological case where I is I<\"/\">.)" msgstr "" #. type: SH #: debian-bookworm #, no-wrap msgid "VERSIONS" msgstr "" #. type: Plain text #: debian-bookworm msgid "B() was introduced in Linux 2.3.41." msgstr "" #. type: Plain text #: debian-bookworm msgid "B() is Linux-specific and hence is not portable." msgstr "" #. type: Plain text #: debian-bookworm fedora-40 mageia-cauldron opensuse-leap-15-6 msgid "" "This sequence succeeds because the B() call stacks the old root " "mount point on top of the new root mount point at I. At that point, the " "calling process's root directory and current working directory refer to the " "new root mount point (I). During the subsequent B() " "call, resolution of I<\".\"> starts with I and then moves up the " "list of mounts stacked at I, with the result that old root mount point is " "unmounted." msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "/* pivot_root_demo.c */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" "#define _GNU_SOURCE\n" "#include Eerr.hE\n" "#include Elimits.hE\n" "#include Esched.hE\n" "#include Esignal.hE\n" "#include Estdio.hE\n" "#include Estdlib.hE\n" "#include Esys/mman.hE\n" "#include Esys/mount.hE\n" "#include Esys/stat.hE\n" "#include Esys/syscall.hE\n" "#include Esys/wait.hE\n" "#include Eunistd.hE\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" "static int\n" "pivot_root(const char *new_root, const char *put_old)\n" "{\n" " return syscall(SYS_pivot_root, new_root, put_old);\n" "}\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "#define STACK_SIZE (1024 * 1024)\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" "static int /* Startup function for cloned child */\n" "child(void *arg)\n" "{\n" " char path[PATH_MAX];\n" " char **args = arg;\n" " char *new_root = args[0];\n" " const char *put_old = \"/oldrootfs\";\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " /* Ensure that \\[aq]new_root\\[aq] and its parent mount don\\[aq]t have\n" " shared propagation (which would cause pivot_root() to\n" " return an error), and prevent propagation of mount\n" " events to the initial mount namespace. */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " if (mount(NULL, \"/\", NULL, MS_REC | MS_PRIVATE, NULL) == -1)\n" " err(EXIT_FAILURE, \"mount-MS_PRIVATE\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid " /* Ensure that \\[aq]new_root\\[aq] is a mount point. */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " if (mount(new_root, new_root, NULL, MS_BIND, NULL) == -1)\n" " err(EXIT_FAILURE, \"mount-MS_BIND\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid " /* Create directory to which old root will be pivoted. */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " snprintf(path, sizeof(path), \"%s/%s\", new_root, put_old);\n" " if (mkdir(path, 0777) == -1)\n" " err(EXIT_FAILURE, \"mkdir\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid " /* And pivot the root filesystem. */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " if (pivot_root(new_root, path) == -1)\n" " err(EXIT_FAILURE, \"pivot_root\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid " /* Switch the current working directory to \"/\". */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " if (chdir(\"/\") == -1)\n" " err(EXIT_FAILURE, \"chdir\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid " /* Unmount old root and remove mount point. */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " if (umount2(put_old, MNT_DETACH) == -1)\n" " perror(\"umount2\");\n" " if (rmdir(put_old) == -1)\n" " perror(\"rmdir\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid " /* Execute the command specified in argv[1]... */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " execv(args[1], &args[1]);\n" " err(EXIT_FAILURE, \"execv\");\n" "}\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" "int\n" "main(int argc, char *argv[])\n" "{\n" " char *stack;\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid " /* Create a child process in a new mount namespace. */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " stack = mmap(NULL, STACK_SIZE, PROT_READ | PROT_WRITE,\n" " MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);\n" " if (stack == MAP_FAILED)\n" " err(EXIT_FAILURE, \"mmap\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " if (clone(child, stack + STACK_SIZE,\n" " CLONE_NEWNS | SIGCHLD, &argv[1]) == -1)\n" " err(EXIT_FAILURE, \"clone\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid " /* Parent falls through to here; wait for child. */\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " if (wait(NULL) == -1)\n" " err(EXIT_FAILURE, \"wait\");\n" msgstr "" #. type: Plain text #: debian-bookworm opensuse-leap-15-6 #, no-wrap msgid "" " exit(EXIT_SUCCESS);\n" "}\n" msgstr "" #. type: TH #: fedora-40 mageia-cauldron #, no-wrap msgid "2023-10-31" msgstr "" #. type: TH #: fedora-40 mageia-cauldron #, no-wrap msgid "Linux man-pages 6.06" msgstr "" #. type: TH #: fedora-rawhide #, no-wrap msgid "2024-02-25" msgstr "" #. type: TH #: fedora-rawhide #, no-wrap msgid "Linux man-pages 6.7" msgstr "" #. type: TH #: opensuse-leap-15-6 #, no-wrap msgid "2023-03-30" msgstr "" #. type: TH #: opensuse-leap-15-6 #, no-wrap msgid "Linux man-pages 6.04" msgstr "" #. type: TH #: opensuse-tumbleweed #, no-wrap msgid "Linux man-pages (unreleased)" msgstr ""