Linux /lib and its architecture!
Guide outline
- 1.1. Overview
- 1.2. The Root Directory
- 1.3. /bin
- 1.4. /boot
- 1.5. /dev
- 1.6. /etc
- 1.7. /home
- 1.8. /initrd
- 1.9. /lib
- 1.10. /lost+found
- 1.11. /media
- 1.12. /mnt
- 1.13. /opt
- 1.14. /proc
- 1.15. /root
- 1.16. /sbin
- 1.17. /usr
- 1.18. /var
- 1.19. /srv
- 1.20. /tmp
- 2. Glossary
Additional Linux Resources
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1.9. /lib
The /lib directory contains kernel modules and those shared library images (the C programming code library) needed to boot the system and run the commands in the root filesystem, ie. by binaries in /bin and /sbin. Libraries are readily identifiable through their filename extension of *.so. Windows equivalent to a shared library would be a DLL (dynamically linked library) file. They are essential for basic system functionality. Kernel modules (drivers) are in the subdirectory /lib/modules/’kernel-version’. To ensure proper module compilation you should ensure that /lib/modules/’kernel-version’/kernel/build points to /usr/src/’kernel-version’ or ensure that the Makefile knows where the kernel source itself are located.
- /lib/’machine-architecture’
- Contains platform/architecture dependent libraries.
- /lib/iptables
- iptables shared library files.
- /lib/kbd
- Contains various keymaps.
- /lib/modules/’kernel-version’
- The home of all the kernel modules. The organisation of files here is reasonably clear so no requires no elaboration.
- /lib/modules/’kernel-version’/isapnpmap.dep
- has details on ISA based cards, the modules that they require and various other attributes.
- /lib/modules/’kernel-version’/modules.dep
- lists all modules dependencies. This file can be updated using the depmod command.
- /lib/modules/’kernel-version’/pcimap
- is the PCI equivalent of the /lib/modules/’kernel-version’/isapnpmap.dep file.
- /lib/modules/’kernel-version’/usbmap
- is the USB equivalent of the /lib/modules/’kernel-version’/isapnpmap.dep file.
- /lib/oss
- All OSS (Open Sound System) files are installed here by default.
- /lib/security
- PAM library files.
The FSSTND states that the /lib directory contains those shared library images needed to boot the system and run the commands in the root filesystem, ie. by binaries in /bin and /sbin. Shared libraries that are only necessary for binaries in /usr (such as any X Window binaries) must not be in /lib. Only the shared libraries required to run binaries in /bin and /sbin may be here. In particular, the library libm.so.* may also be placed in /usr/lib if it is not required by anything in /bin or /sbin. At least one of each of the following filename patterns are required (they may be files, or symbolic links): libc.so.* The dynamically-linked C library (optional) ld* The execution time linker/loader (optional) If a C preprocessor is installed, /lib/cpp must be a reference to it, for historical reasons. The usual placement of this binary is /usr/bin/cpp. The following directories, or symbolic links to directories, must be in /lib, if the corresponding subsystem is installed: modules Loadable kernel modules (optional) /lib<qual> : Alternate format essential shared libraries (optional) There may be one or more variants of the /lib directory on systems which support more than one binary format requiring separate libraries. This is commonly used for 64-bit or 32-bit support on systems which support multiple binary formats, but require libraries of the same name. In this case, /lib32 and /lib64 might be the library directories, and /lib a symlink to one of them. If one or more of these directories exist, the requirements for their contents are the same as the normal /lib directory, except that /lib<qual>/cpp is not required. /lib<qual>/cpp is still permitted: this allows the case where /lib and /lib<qual> are the same (one is a symbolic link to the other). |