bionic/libc
Nick Kralevich 36bd371e26 Revert "stack protector: use AT_RANDOM"
The AT_RANDOM changes broke setuid / setgid executables
such as "ping". When the linker executes a setuid program,
it cleans the environment, removing any invalid environment
entries, and adding "NULL"s to the end of the environment
array for each removed variable. Later on, we try to determine
the location of the aux environment variable, and get tripped
up by these extra NULLs.

Reverting this patch will get setuid executables working again,
but getauxval() is still broken for setuid programs because of
this bug.

This reverts commit e3a49a8661.

Change-Id: I05c58a896b1fe32cfb5d95d43b096045cda0aa4a
2013-01-16 13:16:42 -08:00
..
arch-arm Add __aeabi_idiv to the dummy reference list. 2013-01-14 15:33:40 -08:00
arch-mips Add signalfd call to bionic 2013-01-10 13:14:46 -08:00
arch-x86 Add signalfd call to bionic 2013-01-10 13:14:46 -08:00
bionic Revert "stack protector: use AT_RANDOM" 2013-01-16 13:16:42 -08:00
docs Remove obsolete CHANGES.TXT and ISSUES.TXT. 2012-10-17 11:33:59 -07:00
include Fix signalfd for MIPS. 2013-01-16 09:40:25 -08:00
kernel headers: update auxvec.h from Linux kernel 2013-01-14 11:49:59 -08:00
netbsd More upstream NetBSD upgrades. 2012-10-23 16:05:09 -07:00
private Revert "stack protector: use AT_RANDOM" 2013-01-16 13:16:42 -08:00
stdio Define DEFFILEMODE and friends 2012-11-29 11:53:33 -08:00
stdlib More upstream NetBSD upgrades. 2012-10-23 16:05:09 -07:00
string clean up FORTIFY_SOURCE handling. 2012-12-04 15:27:30 -08:00
tools Verify architecture neutral syscall numbers 2012-11-29 12:04:23 -08:00
tzcode Revert "DO NOT MERGE Revert "Add the libcutils localtime_tz and mktime_t extensions to bionic."" 2013-01-15 11:12:18 -08:00
unistd More upstream NetBSD upgrades. 2012-10-23 16:05:09 -07:00
upstream-dlmalloc Fix build warning of initialization but no use. 2012-09-06 09:59:13 -07:00
upstream-netbsd libc: Fix alphasort() signature (and implementation). 2012-10-29 07:44:27 -07:00
wchar Move non-upstream code into the libc/bionic directory. 2012-10-01 17:35:49 -07:00
zoneinfo Upgrade to tzdata2012j. 2012-11-26 14:51:39 -08:00
Android.mk libc: add getauxval() 2013-01-11 16:44:15 -08:00
CAVEATS auto import from //depot/cupcake/@135843 2009-03-03 19:28:35 -08:00
MODULE_LICENSE_BSD auto import from //depot/cupcake/@135843 2009-03-03 19:28:35 -08:00
NOTICE Update generate-NOTICE.py to know about tzdata. 2012-10-19 14:55:19 -07:00
README Add an 's and a . to the bionic/libc README. 2009-07-23 17:41:47 -07:00
SYSCALLS.TXT Add signalfd call to bionic 2013-01-10 13:14:46 -08:00

Welcome to Bionic, Android's small and custom C library for the Android
platform.

Bionic is mainly a port of the BSD C library to our Linux kernel with the
following additions/changes:

- no support for locales
- no support for wide chars (i.e. multi-byte characters)
- its own smallish implementation of pthreads based on Linux futexes
- support for x86, ARM and ARM thumb CPU instruction sets and kernel interfaces

Bionic is released under the standard 3-clause BSD License

Bionic doesn't want to implement all features of a traditional C library, we only
add features to it as we need them, and we try to keep things as simple and small
as possible. Our goal is not to support scaling to thousands of concurrent threads
on multi-processors machines; we're running this on cell-phones, damnit !!

Note that Bionic doesn't provide a libthread_db or a libm implementation.


Adding new syscalls:
====================

Bionic provides the gensyscalls.py Python script to automatically generate syscall
stubs from the list defined in the file SYSCALLS.TXT. You can thus add a new syscall
by doing the following:

- edit SYSCALLS.TXT
- add a new line describing your syscall, it should look like:

   return_type  syscall_name(parameters)    syscall_number

- in the event where you want to differentiate the syscall function from its entry name,
  use the alternate:

   return_type  funcname:syscall_name(parameters)  syscall_number

- additionally, if the syscall number is different between ARM and x86, use:

   return_type  funcname[:syscall_name](parameters)   arm_number,x86_number

- a syscall number can be -1 to indicate that the syscall is not implemented on
  a given platform, for example:

   void   __set_tls(void*)   arm_number,-1


the comments in SYSCALLS.TXT contain more information about the line format

You can also use the 'checksyscalls.py' script to check that all the syscall
numbers you entered are correct. It does so by looking at the values defined in
your Linux kernel headers. The script indicates where the values are incorrect
and what is expected instead.