diff --git a/chapter01/changelog.xml b/chapter01/changelog.xml index e65ee12b7..f99510bd3 100644 --- a/chapter01/changelog.xml +++ b/chapter01/changelog.xml @@ -39,6 +39,16 @@ or as appropriate for the entry or if needed the entire day's listitem. --> + + 2022-12-28 + + + [renodr] - Patch systemd against CVE-2022-4415. Fixes + #5187. + + + + 2022-12-31 @@ -91,7 +101,7 @@ [bdubbs] - Update to vim-9.0.1060. Addresses - #5006. + #4500. [bdubbs] - Update to iproute2-6.1.0. Fixes diff --git a/chapter01/whatsnew.xml b/chapter01/whatsnew.xml index 207240036..86992592b 100644 --- a/chapter01/whatsnew.xml +++ b/chapter01/whatsnew.xml @@ -299,6 +299,10 @@ &readline-fixes-patch; + + + &systemd-upstream-patch; + diff --git a/chapter03/patches.xml b/chapter03/patches.xml index 033ccd00c..05b49d319 100644 --- a/chapter03/patches.xml +++ b/chapter03/patches.xml @@ -135,7 +135,7 @@ - + pwdx diff --git a/chapter08/stripping.xml b/chapter08/stripping.xml index d82b72ac1..eaabab5b7 100644 --- a/chapter08/stripping.xml +++ b/chapter08/stripping.xml @@ -12,39 +12,39 @@ This section is optional. If the intended user is not a programmer and does not plan to do - any debugging on the system software, the system size can be decreased - by about 2 GB by removing the debugging symbols and unneeded symbol table - entries from binaries and libraries. This causes no inconvenience other - than not being able to debug the software fully anymore. + any debugging of the system software, the system's size can be decreased + by some 2 GB by removing the debugging symbols, and some unnecessary symbol table + entries, from binaries and libraries. This causes no real inconvenience for + a typical Linux user. Most people who use the commands mentioned below do not - experience any difficulties. However, it is easy to make a typo and - render the new system unusable, so before running the + experience any difficulties. However, it is easy to make a mistake and + render the new system unusable. So before running the strip commands, it is a good idea to make a backup of the LFS system in its current state. - A strip command with + A strip command with the --strip-unneeded option removes all debug symbols - from a binary or library. And, it removes all symbol table entries not + from a binary or library. It also removes all symbol table entries not needed by the linker (for static libraries) or dynamic linker (for - dynamic-linked binaries and shared libraries). + dynamically linked binaries and shared libraries). - The debugging symbols for selected libraries are placed - in separate files. This debugging information is needed if running - regression tests that use The debugging symbols from selected libraries are preserved + in separate files. That debugging information is needed to run + regression tests with valgrind or gdb later in BLFS. + url='&blfs-book;/general/gdb.html'>gdb later, in BLFS. Note that strip will overwrite the binary or library file it is processing. This can crash the processes using code or data from - the file. If the process running strip itself is - affected, the binary or library being stripped can be destroyed and can - make the system completely unusable. To avoid it, we'll copy some libraries + the file. If the process running strip is + affected, the binary or library being stripped can be destroyed; this can + make the system completely unusable. To avoid this problem we copy some libraries and binaries into /tmp, strip them - there, and install them back with the install command. - Read the related entry in for the - rationale to use the install command here. + there, then reinstall them with the install command. + (The related entry in gives the + rationale for using the install command here.) The ELF loader's name is ld-linux-x86-64.so.2 on 64-bit systems and ld-linux.so.2 on 32-bit systems. The construct below selects the @@ -111,8 +111,8 @@ done unset BIN LIB save_usrlib online_usrbin online_usrlib - A large number of files will be reported as having their file - format not recognized. These warnings can be safely ignored. They - indicate that those files are scripts instead of binaries. + A large number of files will be flagged as errors because their file + format is not recognized. These warnings can be safely ignored. They + indicate that those files are scripts, not binaries. diff --git a/chapter08/sysklogd.xml b/chapter08/sysklogd.xml index 9aec7ba9b..89fc314ed 100644 --- a/chapter08/sysklogd.xml +++ b/chapter08/sysklogd.xml @@ -23,8 +23,8 @@ - <para>The sysklogd package contains programs for logging system messages, - such as those given by the kernel when unusual things happen.</para> + <para>The Sysklogd package contains programs for logging system messages, + such as those emitted by the kernel when unusual things happen.</para> <segmentedlist> <segtitle>&buildtime;</segtitle> @@ -41,8 +41,8 @@ <sect2 role="installation"> <title>Installation of Sysklogd - First, fix problems that causes a segmentation fault under - some conditions in klogd and fix an obsolete program construct: + First, fix a problem that causes a segmentation fault in klogd + under some conditions, and fix an obsolete program construct: sed -i '/Error loading kernel symbols/{n;n;d}' ksym_mod.c sed -i 's/union wait/int/' syslogd.c diff --git a/chapter08/systemd.xml b/chapter08/systemd.xml index 4548056ea..2c5c0e11b 100644 --- a/chapter08/systemd.xml +++ b/chapter08/systemd.xml @@ -40,11 +40,11 @@ Installation of systemd - + Remove two unneeded groups, render and diff --git a/chapter08/sysvinit.xml b/chapter08/sysvinit.xml index 0d6914a45..7b31ec007 100644 --- a/chapter08/sysvinit.xml +++ b/chapter08/sysvinit.xml @@ -115,7 +115,7 @@ fstab-decode - Run a command with fstab-encoded arguments + Runs a command with fstab-encoded arguments fstab-decode @@ -126,10 +126,10 @@ halt Normally invokes shutdown with the - -h option, except when already in run-level 0, - then it tells the kernel to halt the system; it notes in the - file /var/log/wtmp that the system is being - brought down + -h option, but when already in run-level 0, + it tells the kernel to halt the system; it notes in the + file /var/log/wtmp that the system is + going down halt @@ -140,8 +140,8 @@ init The first process to be started when the kernel has initialized - the hardware which takes over the boot process and starts all the - proceses specified in its configuration file + the hardware; it takes over the boot process and starts all the + processes specified in its configuration file init @@ -152,7 +152,7 @@ killall5 Sends a signal to all processes, except the processes in its own - session so it will not kill its parent shell + session; it will not kill its parent shell killall5 diff --git a/chapter08/util-linux.xml b/chapter08/util-linux.xml index 7648d2a7f..221743d3d 100644 --- a/chapter08/util-linux.xml +++ b/chapter08/util-linux.xml @@ -77,7 +77,7 @@ --docdir=/usr/share/doc/util-linux-&util-linux-version; The --disable and --without options prevent warnings about - building components that require packages not in LFS or are + building components that either require packages not in LFS, or are inconsistent with programs installed by other packages. Compile the package: @@ -92,7 +92,7 @@ be available in the currently running system and must be built as a module. Building it into the kernel will prevent booting. For complete coverage, other BLFS packages must be installed. If desired, this test can - be run after rebooting into the completed LFS system and running: + be run by booting into the completed LFS system and running: bash tests/run.sh --srcdir=$PWD --builddir=$PWD @@ -125,16 +125,17 @@ su tester -c "make -k check" addpart, agetty, blkdiscard, blkid, blkzone, blockdev, cal, cfdisk, chcpu, chmem, choom, chrt, col, colcrt, colrm, column, ctrlaltdel, delpart, dmesg, eject, fallocate, fdisk, fincore, findfs, findmnt, flock, fsck, - fsck.cramfs, fsck.minix, fsfreeze, fstrim, getopt, hexdump, hwclock, - i386, ionice, ipcmk, ipcrm, ipcs, irqtop, isosize, kill, last, lastb (link to - last), ldattach, linux32, linux64, logger, look, losetup, lsblk, lscpu, - lsipc, lsirq, lslocks, lslogins, lsmem, lsns, mcookie, mesg, mkfs, mkfs.bfs, mkfs.cramfs, mkfs.minix, mkswap, + fsck.cramfs, fsck.minix, fsfreeze, fstrim, getopt, hardlink, hexdump, hwclock, + i386 (link to setarch), ionice, ipcmk, ipcrm, ipcs, irqtop, isosize, kill, last, + lastb (link to last), ldattach, linux32 (link to setarch), linux64 (link to setarch), + logger, look, losetup, lsblk, lscpu, lsipc, lsirq, lsfd, lslocks, lslogins, + lsmem, lsns, mcookie, mesg, mkfs, mkfs.bfs, mkfs.cramfs, mkfs.minix, mkswap, more, mount, mountpoint, namei, nsenter, partx, pivot_root, prlimit, readprofile, rename, renice, resizepart, rev, rfkill, rtcwake, script, scriptlive, scriptreplay, setarch, setsid, setterm, sfdisk, sulogin, swaplabel, - swapoff (link to swapon), swapon, switch_root, taskset, uclampset, ul, - umount, uname26, unshare, utmpdump, uuidd, uuidgen, uuidparse, wall, wdctl, whereis, - wipefs, x86_64, and zramctl + swapoff, swapon, switch_root, taskset, uclampset, ul, + umount, uname26 (link to setarch), unshare, utmpdump, uuidd, uuidgen, uuidparse, + wall, wdctl, whereis, wipefs, x86_64 (link to setarch), and zramctl libblkid.so, libfdisk.so, libmount.so, libsmartcols.so, and libuuid.so /usr/include/blkid, @@ -197,7 +198,7 @@ su tester -c "make -k check" blkzone - Runs zone command on the given block device + Is used to manage zoned storage block devices blkzone @@ -258,7 +259,8 @@ su tester -c "make -k check" choom - Displays and adjusts OOM-killer score + Displays and adjusts OOM-killer scores, used to determine + which process to kill first when Linux is Out Of Memory choom @@ -390,7 +392,7 @@ su tester -c "make -k check" findfs - Finds a file system by label or Universally Unique Identifier + Finds a file system, either by label or Universally Unique Identifier (UUID) findfs @@ -402,7 +404,7 @@ su tester -c "make -k check" findmnt Is a command line interface to the libmount library - for work with mountinfo, fstab and mtab files + for working with mountinfo, fstab and mtab files findmnt @@ -482,12 +484,22 @@ su tester -c "make -k check" + + + hardlink + + Consolidates duplicate files by creating hard links + + hardlink + + + hexdump - Dumps the given file in hexadecimal or in another given - format + Dumps the given file in hexadecimal, decimal, octal, + or ascii hexdump @@ -690,6 +702,16 @@ su tester -c "make -k check" + + + lsfd + + Displays information about open files; replaces lsof + + lsfd + + + lsipc @@ -861,7 +883,7 @@ su tester -c "make -k check" namei - Shows the symbolic links in the given pathnames + Shows the symbolic links in the given paths namei @@ -903,7 +925,7 @@ su tester -c "make -k check" prlimit - Get and set a process' resource limits + Gets and sets a process's resource limits prlimit @@ -974,7 +996,7 @@ su tester -c "make -k check" rtcwake - Used to enter a system sleep state until specified wakeup + Used to enter a system sleep state until the specified wakeup time rtcwake @@ -995,7 +1017,7 @@ su tester -c "make -k check" scriptlive - Re-run session typescripts using timing information + Re-runs session typescripts using timing information scriptlive @@ -1015,7 +1037,7 @@ su tester -c "make -k check" setarch - Changes reported architecture in a new program environment and + Changes reported architecture in a new program environment, and sets personality flags setarch @@ -1068,7 +1090,7 @@ su tester -c "make -k check" swaplabel - Allows to change swaparea UUID and label + Makes changes to the swap area's UUID and label swaplabel @@ -1088,7 +1110,7 @@ su tester -c "make -k check" swapon - Enables devices and files for paging and swapping and + Enables devices and files for paging and swapping, and lists the devices and files currently in use swapon @@ -1109,7 +1131,7 @@ su tester -c "make -k check" taskset - Retrieves or sets a process' CPU affinity + Retrieves or sets a process's CPU affinity taskset @@ -1119,7 +1141,7 @@ su tester -c "make -k check" uclampset - Manipulate the utilization clamping attributes of the + Manipulates the utilization clamping attributes of the system or a process uclampset @@ -1171,7 +1193,7 @@ su tester -c "make -k check" utmpdump - Displays the content of the given login file in a more + Displays the content of the given login file in a user-friendly format utmpdump @@ -1193,9 +1215,10 @@ su tester -c "make -k check" uuidgen - Creates new UUIDs. Each new UUID can reasonably be considered + Creates new UUIDs. Each new UUID is a random number likely to be unique among all UUIDs created, on the local system and on other - systems, in the past and in the future + systems, in the past and in the future, with extremely high + probability (~340 trillion trillion trillion unique UUIDs are possible) uuidgen @@ -1205,7 +1228,7 @@ su tester -c "make -k check" uuidparse - An utility to parse unique identifiers + A utility to parse unique identifiers uuidparse @@ -1237,7 +1260,7 @@ su tester -c "make -k check" whereis Reports the location of the binary, source, and man page - for the given command + files for the given command whereis diff --git a/chapter09/bootscripts.xml b/chapter09/bootscripts.xml index cb88a9fd8..fbffa76df 100644 --- a/chapter09/bootscripts.xml +++ b/chapter09/bootscripts.xml @@ -74,7 +74,7 @@ checkfs Checks the integrity of the file systems before they are mounted - (with the exception of journal and network based file systems) + (with the exception of journaling and network-based file systems) checkfs @@ -173,8 +173,8 @@ mountfs - Mounts all file systems, except ones that are marked - noauto or are network based + Mounts all file systems, except those that are marked + noauto, or are network based mountfs @@ -208,7 +208,7 @@ The master run-level control script; it is responsible for running all the other bootscripts one-by-one, in a sequence determined - by the name of the symbolic links being processed + by the names of the symbolic links to those other bootscripts rc @@ -239,8 +239,8 @@ setclock - Resets the kernel clock to local time in case the hardware clock - is not set to UTC time + Resets the system clock to local time if the hardware clock + is not set to UTC setclock @@ -305,7 +305,7 @@ udev Prepares the /dev - directory and starts Udev + directory and starts the udev daemon udev diff --git a/chapter09/introduction.xml b/chapter09/introduction.xml index da5ffe67c..745ca3165 100644 --- a/chapter09/introduction.xml +++ b/chapter09/introduction.xml @@ -11,19 +11,19 @@ Introduction Booting a Linux system involves several tasks. The process must - mount both virtual and real file systems, initialize devices, activate swap, - check file systems for integrity, mount any swap partitions or files, set + mount both virtual and real file systems, initialize devices, + check file systems for integrity, mount and activate any swap partitions or files, set the system clock, bring up networking, start any daemons required by the - system, and accomplish any other custom tasks needed by the user. This + system, and accomplish any other custom tasks specified by the user. This process must be organized to ensure the tasks are performed in the correct - order but, at the same time, be executed as fast as possible. + order and executed as quickly as possible. System V System V is the classic boot process that has been used in Unix and Unix-like systems such as Linux since about 1983. It consists of a small - program, init, that sets up basic programs such as + program, init, that sets up basic processes such as login (via getty) and runs a script. This script, usually named rc, controls the execution of a set of additional scripts that perform the tasks required to initialize the @@ -31,7 +31,7 @@ The init program is controlled by the /etc/inittab file and is organized into run levels that - can be run by the user. In LFS, they are used as follows: + can be chosen by the user. In LFS, they are used as follows: 0 — halt 1 — Single user mode @@ -70,13 +70,13 @@ Serial processing of boot tasks. This is related to the previous - point. A delay in any process such as a file system check, will + point. A delay in any process, such as a file system check, will delay the entire boot process. Does not directly support advanced features like - control groups (cgroups), and per-user fair share scheduling. + control groups (cgroups) and per-user fair share scheduling. diff --git a/chapter09/network.xml b/chapter09/network.xml index 5ea7e3add..e2d0a5edf 100644 --- a/chapter09/network.xml +++ b/chapter09/network.xml @@ -17,15 +17,15 @@ Creating Network Interface Configuration Files - Which interfaces are brought up and down by the network script - usually depends on the files in /etc/sysconfig/. This directory should + The files in /etc/sysconfig/ + usually determine which interfaces are brought up and down by the network + script. This directory should contain a file for each interface to be configured, such as - ifconfig.xyz, where xyz should describe + ifconfig.xyz, where xyz describes the network card. The interface name (e.g. eth0) is usually appropriate. - Inside this file are attributes to this interface, such as its IP - address(es), subnet masks, and so forth. It is necessary that the stem of - the filename be ifconfig. + Each file contains the attributes of one interface, such as its IP + address(es), subnet masks, and so forth. The stem of + the filename must be ifconfig. If the procedure in the previous section was not used, udev @@ -38,10 +38,10 @@ The interface names depend on the implementation and configuration of the udev daemon running on the system. The udev daemon for LFS (installed in ) will - not run until the LFS system is booted. So it's unreliable to - determine the interface names being used in LFS system by running + not run until the LFS system is booted. So the interface names + in the LFS system cannot always be determined by running those commands on the host distro, - even though in the chroot environment. + even in the chroot environment. The following command creates a sample file for the @@ -59,14 +59,14 @@ PREFIX=24 BROADCAST=192.168.1.255 EOF - The values in italics must be changed in every file to match - the proper setup. + The values in italics must be changed in each file, to set + the interfaces up correctly. If the ONBOOT variable is set to yes the System V network script will bring up the Network Interface Card (NIC) during - the system boot process. If set to anything but yes the NIC - will be ignored by the network script and not be automatically brought up. - The interface can be manually started or stopped with the + the system boot process. If set to anything besides yes, the NIC + will be ignored by the network script and will not be started automatically. + Interfaces can be manually started or stopped with the ifup and ifdown commands. The IFACE variable defines the interface name, @@ -84,11 +84,11 @@ EOF gateway IP address, if one is present. If not, then comment out the variable entirely. - The PREFIX variable contains the number of - bits used in the subnet. Each octet in an IP address is 8 bits. If the - subnet's netmask is 255.255.255.0, then it is using the first three octets + The PREFIX variable specifies the number of + bits used in the subnet. Each segment of an IP address is 8 bits. If the + subnet's netmask is 255.255.255.0, then it is using the first three segments (24 bits) to specify the network number. If the netmask is 255.255.255.240, - it would be using the first 28 bits. Prefixes longer than 24 bits are + the subnet is using the first 28 bits. Prefixes longer than 24 bits are commonly used by DSL and cable-based Internet Service Providers (ISPs). In this example (PREFIX=24), the netmask is 255.255.255.0. Adjust the PREFIX variable according to your specific subnet. @@ -139,7 +139,7 @@ EOF - Configuring the system hostname + Configuring the System Hostname hostname @@ -156,7 +156,7 @@ EOF <lfs> needs to be replaced with the name given to the computer. Do not enter the Fully Qualified Domain Name - (FQDN) here. That information is put in the + (FQDN) here. That information goes in the /etc/hosts file. diff --git a/chapter09/symlinks.xml b/chapter09/symlinks.xml index 24ebf537d..86528ba69 100644 --- a/chapter09/symlinks.xml +++ b/chapter09/symlinks.xml @@ -17,27 +17,28 @@ Udev, by default, names network devices according to Firmware/BIOS data or physical characteristics like the bus, slot, or MAC address. The purpose of this naming convention is to ensure that network devices are - named consistently and not based on the time the network card was - discovered. For example, on a computer having two network cards made by - Intel and Realtek, the network card manufactured by Intel may become eth0 - and the Realtek card becomes eth1. In some cases, after a reboot the cards - could get renumbered the other way around. + named consistently, not based on when the network card was + discovered. In older versions of Linux—on a computer with two + network cards made by Intel and Realtek, for instance—the + network card manufactured by Intel might have become eth0 + while the Realtek card became eth1. After a reboot, the cards + would sometimes get renumbered the other way around. - In the new naming scheme, typical network device names would then - be something like enp5s0 or wlp3s0. If this naming convention is not - desired, the traditional naming scheme or a custom scheme can be + In the new naming scheme, typical network device names are + something like enp5s0 or wlp3s0. If this naming convention is not + desired, the traditional naming scheme, or a custom scheme, can be implemented. Disabling Persistent Naming on the Kernel Command Line - The traditional naming scheme using eth0, eth1, etc can be + The traditional naming scheme using eth0, eth1, etc. can be restored by adding net.ifnames=0 on the - kernel command line. This is most appropriate for those systems - that have only one ethernet device of the same type. Laptops - often have multiple ethernet connections that are named eth0 and - wlan0 and are also candidates for this method. The command line - is passed in the GRUB configuration file. + kernel command line. This is most appropriate for systems + that have just one ethernet device of a particular type. Laptops + often have two ethernet connections named eth0 and + wlan0; such laptops can also use this method. The command line + is in the GRUB configuration file. See . @@ -56,23 +57,22 @@ cat /etc/udev/rules.d/70-persistent-net.rules - In some cases such as when MAC addresses have been assigned to - a network card manually or in a virtual environment such as Qemu or Xen, - the network rules file may not have been generated because addresses + In some cases, such as when MAC addresses have been assigned to + a network card manually, or in a virtual environment such as Qemu or Xen, + the network rules file may not be generated because addresses are not consistently assigned. In these cases, this method cannot be used. - The file begins with a comment block followed by two lines for each + The file begins with a comment block, followed by two lines for each NIC. The first line for each NIC is a commented description showing its hardware IDs (e.g. its PCI vendor and device IDs, if it's a PCI card), - along with its driver in parentheses, if the driver can be found. Neither + along with its driver (in parentheses, if the driver can be found). Neither the hardware ID nor the driver is used to determine which name to give an interface; this information is only for reference. The second line is the udev rule that matches this NIC and actually assigns it a name. - All udev rules are made up of several keys, separated by commas and - optional whitespace. This rule's keys and an explanation of each of them - are as follows: + All udev rules are made up of several keywords, separated by commas and + optional whitespace. Here are the keywords, and an explanation of each one: @@ -88,10 +88,10 @@ DRIVERS=="?*" - This exists so that udev will ignore VLAN or bridge sub-interfaces (because these sub-interfaces do not have drivers). These sub-interfaces are skipped because the name - that would be assigned would collide with their parent devices. + that would be assigned would collide with the parent devices. - ATTR{address} - The value of this key is the + ATTR{address} - The value of this keyword is the NIC's MAC address. @@ -102,7 +102,7 @@ skipped: there would be a name collision otherwise. - NAME - The value of this key is the name that + NAME - The value of this keyword is the name that udev will assign to this interface. @@ -110,7 +110,7 @@ The value of NAME is the important part. Make sure you know which name has been assigned to each of your network cards before proceeding, and be sure to use that NAME value when - creating your configuration files below. + creating your network configuration files. @@ -118,10 +118,10 @@ - CD-ROM symlinks + CD-ROM Symlinks Some software that you may want to install later (e.g., various - media players) expect the /dev/cdrom + media players) expects the /dev/cdrom and /dev/dvd symlinks to exist, and to point to a CD-ROM or DVD-ROM device. Also, it may be convenient to put references to those symlinks into /etc/fstab. Udev @@ -139,15 +139,15 @@ ata_id or scsi_id programs, depending on which type of device you have. - There are advantages to each approach; the correct approach to use - will depend on what kinds of device changes may happen. If you expect the + There are advantages to each approach; the correct approach + depends on what kinds of device changes may happen. If you expect the physical path to the device (that is, the ports and/or slots that it plugs into) to change, for example because you plan on moving the drive to a different IDE port or a different USB connector, then you should use the by-id mode. On the other hand, if you expect the device's - identification to change, for example because it may die, and you would - replace it with a different device with the same capabilities and which - is plugged into the same connectors, then you should use the + identification to change, for example because it may die, and you intend + to replace it with a different device that + plugs into the same connectors, then you should use the by-path mode. If either type of change is possible with your drive, then choose a @@ -198,13 +198,13 @@ this is only an issue if you need the symlinks on both systems to point to the same device. If you need that, then inspect (and possibly edit) the generated /etc/udev/rules.d/70-persistent-cd.rules - file after booting, to make sure the assigned symlinks match what you need. + file after booting, to make sure the assigned symlinks match your needs. - Dealing with duplicate devices + Dealing with Duplicate Devices As explained in , the order in which devices with the same function appear in @@ -214,7 +214,7 @@ /dev/video1 refers to the tuner, and sometimes after a reboot the order changes. For all classes of hardware except sound cards and network cards, this is - fixable by creating udev rules for custom persistent symlinks. + fixable by creating udev rules to create persistent symlinks. The case of network cards is covered separately in , and sound card configuration can be found in BLFS. diff --git a/chapter09/udev.xml b/chapter09/udev.xml index 396f2b389..20212035c 100644 --- a/chapter09/udev.xml +++ b/chapter09/udev.xml @@ -16,23 +16,23 @@ In , we installed the udev - package when eudev + daemon when eudev systemd was built. Before we go into the - details regarding how this works, a brief history of previous methods of + details regarding how udev works, a brief history of previous methods of handling devices is in order. Linux systems in general traditionally used a static device creation method, whereby a great many device nodes were created under /dev (sometimes literally thousands of nodes), regardless of whether the corresponding hardware devices actually existed. This - was typically done via a MAKEDEV script, which contains a + was typically done via a MAKEDEV script, which contained a number of calls to the mknod program with the relevant major and minor device numbers for every possible device that might exist in the world. - Using the udev method, only those devices which are detected by the - kernel get device nodes created for them. Because these device nodes will be - created each time the system boots, they will be stored on a Using the udev method, device nodes are only created for those devices + which are detected by the kernel. These device nodes are + created each time the system boots; they are stored in a devtmpfs file system (a virtual file system that resides entirely in system memory). Device nodes do not require much space, so the memory that is used is negligible. @@ -51,23 +51,23 @@ class="filesystem">devfs was the way it handled device detection, creation, and naming. The latter issue, that of device node naming, was perhaps the most critical. It is generally accepted that if - device names are allowed to be configurable, then the device naming policy - should be up to a system administrator, not imposed on them by any - particular developer(s). The devfs file system also suffered from race - conditions that were inherent in its design and could not be fixed without a - substantial revision to the kernel. It was marked as deprecated for a long - period – due to a lack of maintenance – and was finally removed + conditions that were inherent in its design; these could not be fixed without a + substantial revision of the kernel. devfs + was marked as deprecated for a long + time, and was finally removed from the kernel in June, 2006. With the development of the unstable 2.5 kernel tree, later released as the 2.6 series of stable kernels, a new virtual filesystem called sysfs came to be. The job of - sysfs is to export a view of + sysfs is to provide information about the system's hardware configuration to userspace processes. With this - userspace-visible representation, the possibility of developing a userspace - replacement for devfs became - much more realistic. + userspace-visible representation, it became possible to develop a userspace + replacement for devfs. @@ -81,12 +81,13 @@ was mentioned briefly above. One may wonder how sysfs knows about the devices present on a system and what device numbers should be used for them. Drivers that - have been compiled into the kernel directly register their objects with a + have been compiled into the kernel register their objects in sysfs (devtmpfs internally) - as they are detected by the kernel. For drivers compiled as modules, this - registration will happen when the module is loaded. Once the sysfs filesystem is mounted (on /sys), - data which the drivers register with sysfs filesystem is mounted (on + /sys), + data which the drivers have registered with sysfs are available to userspace processes and to udevd for processing (including modifications to device nodes). @@ -96,13 +97,13 @@ Device Node Creation - Device files are created by the kernel by the devtmpfs filesystem. Any driver that - wishes to register a device node will go through the Device files are created by the kernel in the devtmpfs file system. Any driver that + wishes to register a device node will use the devtmpfs (via the driver core) to do it. When a devtmpfs instance is mounted on /dev, the device node - will initially be created with a fixed name, permissions, and + will initially be exposed to userspace with a fixed name, permissions, and owner. A short time later, the kernel will send a uevent to @@ -172,7 +173,7 @@ creating device nodes. - A kernel module is not loaded automatically + A Kernel Module Is Not Loaded Automatically Udev will only load a module if it has a bus-specific alias and the bus driver properly exports the necessary aliases to - A kernel module is not loaded automatically, and udev is not - intended to load it + A Kernel Module Is Not Loaded Automatically, and Udev Is Not + Intended to Load It If the wrapper module only enhances the functionality provided by some other module (e.g., @@ -236,7 +237,7 @@ - Udev loads some unwanted module + Udev Loads Some Unwanted Module Either don't build the module, or blacklist it in a /etc/modprobe.d/blacklist.conf file as done with the @@ -250,7 +251,7 @@ - Udev creates a device incorrectly, or makes a wrong symlink + Udev Creates a Device Incorrectly, or Makes the Wrong Symlink This usually happens if a rule unexpectedly matches a device. For example, a poorly-written rule can match both a SCSI disk (as desired) @@ -261,7 +262,7 @@ - Udev rule works unreliably + Udev Rule Works Unreliably This may be another manifestation of the previous problem. If not, and your rule uses sysfs @@ -275,15 +276,15 @@ - Udev does not create a device + Udev Does Not Create a Device - Further text assumes that the driver is built statically into the - kernel or already loaded as a module, and that you have already checked - that udev doesn't create a misnamed device. + First, be certain that the driver is built into the + kernel or already loaded as a module, and that + udev isn't creating a misnamed device. - Udev has no information needed to create a device node if a kernel - driver does not export its data to - sysfs. This is most common + If a kernel driver does not export its data to + sysfs, udev lacks the + information needed to create a device node. This is most likely to happen with third party drivers from outside the kernel tree. Create a static device node in /usr/lib/udev/devices with the appropriate major/minor numbers (see the file @@ -295,7 +296,7 @@ - Device naming order changes randomly after rebooting + Device Naming Order Changes Randomly After Rebooting This is due to the fact that udev, by design, handles uevents and loads modules in parallel, and thus in an unpredictable order. This will diff --git a/chapter09/usage.xml b/chapter09/usage.xml index 88c0296d6..2e9843988 100644 --- a/chapter09/usage.xml +++ b/chapter09/usage.xml @@ -19,25 +19,29 @@ How Do the System V Bootscripts Work? - Linux uses a special booting facility named SysVinit that is based on a - concept of run-levels. It can be quite different from one - system to another, so it cannot be assumed that because things worked in one - particular Linux distribution, they should work the same in LFS too. LFS has its - own way of doing things, but it respects generally accepted standards. + This version of LFS uses a special booting facility named SysVinit, based on a + series of run levels. The boot procedure can be quite different from one + system to another; the fact that things worked one way in a particular Linux + distribution does not guarantee they will work the same way in LFS. LFS has its + own way of doing things, but it does respect generally accepted standards. + + There is an alternative boot procedure called systemd. We will + not discuss that boot process any further here. For a detailed description visit + . SysVinit (which will be referred to as init from now on) - works using a run-levels scheme. There are seven (numbered 0 to 6) run-levels - (actually, there are more run-levels, but they are for special cases and are - generally not used. See init(8) for more details), and - each one of those corresponds to the actions the computer is supposed to - perform when it starts up. The default run-level is 3. Here are the - descriptions of the different run-levels as they are implemented in LFS: + uses a run levels scheme. There are seven run levels, numbered 0 to 6. + (Actually, there are more run levels, but the others are for special cases and are + generally not used. See init(8) for more details.) + Each one of the seven corresponds to actions the computer is supposed to + perform when it starts up or shuts down. The default run level is 3. Here are the + descriptions of the different run levels as they are implemented in LFS: 0: halt the computer 1: single-user mode -2: reserved for customization, otherwise does the same as 3 +2: reserved for customization, otherwise the same as 3 3: multi-user mode with networking -4: reserved for customization, otherwise does the same as 3 +4: reserved for customization, otherwise the same as 3 5: same as 4, it is usually used for GUI login (like GNOME's gdm or LXDE's lxdm) 6: reboot the computer @@ -45,9 +49,9 @@ Classically, run level 2 above was defined as "multi-user mode without networking", but this was only the case - many years ago when multiple users could log into a system connected via - serial ports. In today's environment it makes no sense and - we designate it now as "reserved". + many years ago when multiple users could connect to a system via + serial ports. In today's environment it makes no sense, and + we now say it is "reserved". @@ -65,8 +69,8 @@ /etc/inittab - During the kernel initialization, the first program that is run - is either specified on the command line or, by default + During kernel initialization, the first program that is run + (if not overridden on the command line) is init. This program reads the initialization file /etc/inittab. Create this file with: @@ -101,8 +105,8 @@ s1:1:respawn:/sbin/sulogin EOF An explanation of this initialization file is in the man page for - inittab. For LFS, the key command that is run is - rc. The initialization file above will instruct + inittab. In LFS, the key command is + rc. The initialization file above instructs rc to run all the scripts starting with an S in the /etc/rc.d/rcS.d directory followed by all the scripts starting with an S in the functions in /lib/lsb/init-functions. This library also reads an optional configuration file, /etc/sysconfig/rc.site. Any of the system - configuration file parameters described in subsequent sections can be - alternatively placed in this file allowing consolidation of all system + configuration parameters described in subsequent sections can be + placed in this file, allowing consolidation of all system parameters in this one file. As a debugging convenience, the functions script also logs all output to /run/var/bootlog. Since the /run directory is a tmpfs, this file is not - persistent across boots, however it is appended to the more permanent file + persistent across boots; however, it is appended to the more permanent file /var/log/boot.log at the end of the boot process. Changing Run Levels - Changing run-levels is done with init + Changing run levels is done with init <runlevel>, where - <runlevel> is the target run-level. For example, to + <runlevel> is the target run level. For example, to reboot the computer, a user could issue the init 6 command, which is an alias for the reboot command. Likewise, init 0 is an alias for the halt @@ -136,15 +140,15 @@ EOF There are a number of directories under /etc/rc.d that look like rc?.d (where ? is the number of the run-level) and + class="directory">rc?.d (where ? is the number of the run level) and rcS.d, all containing a number of - symbolic links. Some begin with a K, the others begin with + symbolic links. Some links begin with a K; the others begin with an S, and all of them have two numbers following the initial letter. The K means to stop (kill) a service and the S means to start a service. The numbers determine the order in which the scripts are run, from 00 - to 99—the lower the number the earlier it gets executed. When - init switches to another run-level, the appropriate services - are either started or stopped, depending on the runlevel chosen. + to 99—the smaller the number, the sooner tht script runs. When + init switches to another run level, the appropriate services + are either started or stopped, depending on the run level chosen. The real scripts are in /etc/rc.d/init.d. They do the actual work, and @@ -227,25 +231,25 @@ EOF The /etc/rc.d/init.d/udev initscript starts udevd, triggers any "coldplug" devices that have - already been created by the kernel and waits for any rules to complete. + already been created by the kernel, and waits for any rules to complete. The script also unsets the uevent handler from the default of /sbin/hotplug . This is done because the kernel no - longer needs to call out to an external binary. Instead + longer needs to call an external binary. Instead, udevd will listen on a netlink socket for uevents that the kernel raises. - The /etc/rc.d/init.d/udev_retry initscript takes + The /etc/rc.d/init.d/udev_retry script takes care of re-triggering events for subsystems whose rules may rely on - filesystems that are not mounted until the mountfs + file systems that are not mounted until the mountfs script is run (in particular, /usr and /var may cause this). This script runs after the mountfs script, so those rules (if re-triggered) should succeed the second time around. It is - configured from the /etc/sysconfig/udev_retry file; + configured by the /etc/sysconfig/udev_retry file; any words in this file other than comments are considered subsystem names to trigger at retry time. To find the subsystem of a device, use udevadm info --attribute-walk <device> where - <device> is an absolute path in /dev or /sys such as /dev/sr0 or + <device> is an absolute path in /dev or /sys, such as /dev/sr0, or /sys/class/rtc. For information on kernel module loading and udev, see @@ -260,13 +264,13 @@ EOF configuring The setclock script reads the time from the hardware - clock, also known as the BIOS or the Complementary Metal Oxide Semiconductor + clock, also known as the BIOS or Complementary Metal Oxide Semiconductor (CMOS) clock. If the hardware clock is set to UTC, this script will convert the hardware clock's time to the local time using the /etc/localtime file (which tells the - hwclock program which timezone to use). There is no + hwclock program which time zone to use). There is no way to detect whether or not the hardware clock is set to UTC, so this - needs to be configured manually. + must be configured manually. The setclock program is run via udev when the kernel detects the hardware @@ -279,9 +283,9 @@ EOF clock. If this time matches whatever your watch says, then the hardware clock is set to local time. If the output from hwclock is not local time, chances are it is set to UTC time. Verify this by adding or subtracting - the proper amount of hours for the timezone to the time shown by + the proper number of hours for your time zone to the time shown by hwclock. For example, if you are currently in the MST - timezone, which is also known as GMT -0700, add seven hours to the local + time zone, which is also known as GMT -0700, add seven hours to the local time. Change the value of the UTC variable below @@ -325,7 +329,7 @@ EOF This section discusses how to configure the console bootscript that sets up the keyboard map, console font, and console kernel log level. If non-ASCII characters (e.g., the copyright sign, the British pound - sign and Euro symbol) will not be used and the keyboard is a U.S. one, much + sign, and the Euro symbol) will not be used and the keyboard is a U.S. one, much of this section can be skipped. Without the configuration file, (or equivalent settings in rc.site), the console bootscript will do nothing. @@ -333,11 +337,11 @@ EOF The console script reads the /etc/sysconfig/console file for configuration information. Decide which keymap and screen font will be used. Various - language-specific HOWTOs can also help with this, see . If still in doubt, look in the /usr/share/keymaps and /usr/share/consolefonts directories - for valid keymaps and screen fonts. Read loadkeys(1) and + for valid keymaps and screen fonts. Read the loadkeys(1) and setfont(8) manual pages to determine the correct arguments for these programs. @@ -358,7 +362,7 @@ EOF KEYMAP This variable specifies the arguments for the - loadkeys program, typically, the name of keymap + loadkeys program, typically, the name of the keymap to load, e.g., it. If this variable is not set, the bootscript will not run the loadkeys program, and the default kernel keymap will be used. Note that a few keymaps @@ -390,11 +394,11 @@ EOF name, -m, and the name of the application character map to load. E.g., in order to load the lat1-16 font together with the 8859-1 application character map - (as it is appropriate in the USA), + (appropriate in the USA), set this variable to lat1-16 -m 8859-1. - In UTF-8 mode, the kernel uses the application character map for - conversion of composed 8-bit key codes in the keymap to UTF-8, and thus + In UTF-8 mode, the kernel uses the application character map to + convert 8-bit key codes to UTF-8. Therefore the argument of the "-m" parameter should be set to the encoding of the composed key codes in the keymap. @@ -404,7 +408,7 @@ EOF UNICODE - Set this variable to 1, yes or + Set this variable to 1, yes, or true in order to put the console into UTF-8 mode. This is useful in UTF-8 based locales and harmful otherwise. @@ -522,7 +526,7 @@ EOF UTF-8 mode it is a problem; e.g., for the Greek language, where one sometimes needs to put an accent on the letter alpha. The solution is either to avoid the use of UTF-8, or to install the - X window system that doesn't have this limitation in its input + X window system, which doesn't have this limitation, in its input handling. @@ -531,7 +535,7 @@ EOF console cannot be configured to display the needed characters. Users who need such languages should install the X Window System, fonts that cover the necessary character ranges, and the proper input method (e.g., - SCIM, supports a wide variety of languages). + SCIM supports a wide variety of languages). @@ -565,7 +569,7 @@ EOF - Configuring the sysklogd Script + Configuring the Sysklogd Script sysklogd @@ -600,8 +604,8 @@ EOF console, and clock files in the /etc/sysconfig/ directory. If the associated variables are present in both these separate files and - rc.site, the values in the script specific files have - precedence. + rc.site, the values in the script-specific files take + effect. rc.site also contains parameters that can customize other aspects of the boot process. Setting the IPROMPT variable @@ -615,8 +619,8 @@ EOF Customizing the Boot and Shutdown Scripts The LFS boot scripts boot and shut down a system in a fairly - efficient manner, but there are a few tweaks that you can make in the - rc.site file to improve speed even more and to adjust messages according + efficient manner, but there are a few tweaks you can make in the + rc.site file to improve speed even more, and to adjust messages according to your preferences. To do this, adjust the settings in the /etc/sysconfig/rc.site file above. @@ -624,18 +628,18 @@ EOF During the boot script udev, there is a call to udev settle that requires some time to - complete. This time may or may not be required depending on devices present + complete. This time may or may not be required depending on the devices in the system. If you only have simple partitions and a single ethernet card, the boot process will probably not need to wait for this command. To skip it, set the variable OMIT_UDEV_SETTLE=y. The boot script udev_retry also runs - udev settle by default. This command is only needed by - default if the /var directory is - separately mounted. This is because the clock needs the file - /var/lib/hwclock/adjtime. Other customizations may + udev settle by default. This command is only needed + if the /var directory is + separately mounted, because the clock needs the + /var/lib/hwclock/adjtime file. Other customizations may also need to wait for udev to complete, but in many installations it is not - needed. Skip the command by setting the variable OMIT_UDEV_RETRY_SETTLE=y. + necessary. Skip the command by setting the variable OMIT_UDEV_RETRY_SETTLE=y. By default, the file system checks are silent. This can @@ -664,7 +668,7 @@ EOF During shutdown, the init program sends a TERM signal to each program it has started (e.g. agetty), waits for a set - time (default 3 seconds), and sends each process a KILL signal and waits + time (default 3 seconds), then sends each process a KILL signal and waits again. This process is repeated in the sendsignals script for any processes that are not shut down by their own scripts. The delay for init can be set by passing a parameter. For diff --git a/patches.ent b/patches.ent index ae4c9946a..ba133d90b 100644 --- a/patches.ent +++ b/patches.ent @@ -91,11 +91,11 @@ - + + + + +