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The Bionic C library

License: Other

Shell 0.05% C 87.83% Assembly 5.13% Objective-C 0.06% C++ 4.23% Python 1.84% Java 0.17% Makefile 0.56% M4 0.13%

bionic's Introduction

The Bionic C Library
=-=-=-=-=-=-=-=-=-=-

This is a fork of the Bionic C Library from the Android Open Source Project.

The original code can be found here[1].

Purpose
=-=-=-=

The purpose of this fork is to allow 3rd party developers to use bionic as
their primary system C library.

The initial port, Gentoo-Bionic[2], mostly focused on Gentoo Linux[3] although
the migration to autotools minimizes that tight coupling. This codebase is
now Linux-distribution-agnostic and therefore can be used (in theory) with any
Linux distribution.

License
=-=-=-=

One of the advantages of using bionic is that it is BSD-licensed (see the file
COPYING). This provides greater flexibility for hardware and software product
vendors when compared with other free-as-in-speach licenses. Indeed, bionic
allows you to have your free-as-in-beer software and use it too.

Since the BSD license has more permissive licensing constraints for API
consumers, people can freely write both open and proprietary software which
links to bionic without much concern of licensing restrictions. However,
please keep in mind, that if Program A links to bionic and Library B,
regardless of whether Library B links to bionic, then Program A still must
abide by the terms and conditions of the Library B software license.

Occasionally, this fork of bionic might incorporate files from other projects
that are similarly permissively licensed. For any questions regarding software
licensing, please email [email protected] .

Modifications
=-=-=-=-=-=-=

1) Use autotools to build rather than the Android build system
2) Use common prefixes for the runtime (e.g. /usr instead of /system)
3) Remove any dependencies on the Android runtime and revert to more
   traditional UNIX practices (e.g. use /etc/resolv.conf instead of
   Android's properties for DNS servers)
4) Add more system calls and libc functions, as appropriate

More information can be found from the original ELC2013 presentation [4].


Happy hacking!


[1] https://android.googlesource.com/platform/bionic.git
[2] https://plus.google.com/113359270067626599390
[3] http://www.gentoo.org
[4] http://elinux.org/images/2/25/2013_elc_gentoo_bionic.pdf

bionic's People

Contributors

Stargazers

Watchers

Forkers

koenkooi steev cfriedt osoc smaznet clintonkildepstein

bionic's Issues

Get rid of __FORCE_THUMB2

A completely arbitrary define (__FORCE_THUMB2) was used to hack thumb / thumb2 support. Rather than using a completely arbitrary define, use the more conventional ones, defined in

libc/arch-arm/include/machine/cpu-features.h

gensyscalls.py should output to $(top_builddir)/libc

Add header install targets

Headers should also be installed to their respective (w.r.t. DESTDIR, prefix) locations.

The kernel header should not be installed in this stage, or it should be optional. This is so that e.g. Gentoo's sys-kernel/bionic-kernel-headers still works.

Modify crt*.o files so that they are compatible with traditional GNU toolchains

modify the crt*.o files, possibly, so that we don't need an -mbionic in GCC

rename crt*.o to be compatible with crti.o, crt1.o, crtn.o, etc
net result is that people can use the same semantics as a -gnu* toolchain

non-PIC bug has shown up again

arch:x86

scanelf -qT libc.so | wc -l
219

most were referencing __set_errno

Run configure & make in a separate directory without errors

This was working. It might still work, but there are probably some kinks to be worked out.

Generally, all BUILT_SOURCES (hint, hint) should be in the build directory and not the source directory.

sys/linux-syscalls.h missing because of python syntax error

This is not related to #28 , but it has a similar symptom; sys/linux-syscalls.h file is also not generated when using python-3.3 (at least with Gentoo/x86). It works by setting the interpreter back to python-2.7 (e.g. eselect set python 1).

python ./libc/tools/gensyscalls.py x86 ./ libc/arch-x86/syscalls > syscalls.stamp
File "./libc/tools/gensyscalls.py", line 22
print "could not find the Bionic root directory. aborting"
...
mkdir -p libc/arch-x86/bionic/
libc/arch-x86/bionic/_exit_with_stack_teardown.S:2:32: fatal error: sys/linux-syscalls.h: No such file or directory
compilation terminated.
libc/arch-x86/bionic/clone.S:2:32: fatal error: sys/linux-syscalls.h: No such file or directory
compilation terminated.
libc/arch-x86/bionic/futex_x86.S:2:32: fatal error: sys/linux-syscalls.h: No such file or directory
compilation terminated.

see http://dev.gentoo.org/~vapier/crt.txt
that means, I should be able to drop it in my /usr/i686-pc-linux-bionic chroot
and it should Just Work (TM)
specifically, when building .so's, the order of the crt*.o files must be specified for the binary to function properly

this means it should work as a drop-in replacement with ldd(1)
also a rename to /lib/ld-linux.so would be awesome
net result is that bionic's linker has the same semantics as a -gnu* toolchain

identify and properly compile .thumb / .arm compilation targets
generate rules