Linux From Scratch - Version r12.2-760-multilib

Chapter 8. Installing Basic System Software

8.27. Libcap-2.71

The Libcap package implements the userspace interface to the POSIX 1003.1e capabilities available in Linux kernels. These capabilities partition the all-powerful root privilege into a set of distinct privileges.

Approximate build time: less than 0.1 SBU
Required disk space: 2.9 MB

8.27.1. Installation of Libcap

Prevent static libraries from being installed: 

sed -i '/install -m.*STA/d' libcap/Makefile

Compile the package: 

make prefix=/usr lib=lib

The meaning of the make option:

lib=lib

This parameter sets the library directory to /usr/lib rather than /usr/lib64 on x86_64. It has no effect on x86.

To test the results, issue: 

make test

Install the package: 

make prefix=/usr lib=lib install

8.27.2. Installation of Libcap - x32bit

Clean previous build: 

make distclean

Compile the package: 

make CC="gcc -mx32 -march=x86-64"

Install the package: 

make CC="gcc -mx32 -march=x86-64" lib=libx32 prefix=$PWD/DESTDIR/usr -C libcap install
cp -Rv DESTDIR/usr/libx32/* /usr/libx32
sed -e "s|^libdir=.*|libdir=/usr/libx32|" -i /usr/libx32/pkgconfig/lib{cap,psx}.pc
chmod -v 755 /usr/libx32/libcap.so.2.71
rm -rf DESTDIR

8.27.3. Contents of Libcap

Installed programs: capsh, getcap, getpcaps, and setcap
Installed library: libcap.so and libpsx.so

Short Descriptions

capsh

A shell wrapper to explore and constrain capability support

getcap

Examines file capabilities

getpcaps

Displays the capabilities of the queried process(es)

setcap

Sets file capabilities

libcap

Contains the library functions for manipulating POSIX 1003.1e capabilities

libpsx

Contains functions to support POSIX semantics for syscalls associated with the pthread library