History log of /bionic/libc/bionic/fork.cpp
Revision Date Author Comments
7086ad6919feb2415c6027163f5c63323bcca27c 20-Jun-2014 Elliott Hughes <enh@google.com> Cache getpid.

In practice, with this implementation we never need to make a system call.
We get the main thread's tid (which is the same as our pid) back from
the set_tid_address system call we have to make during initialization.
A new pthread will have the same pid as its parent, and a fork child's
main (and only) thread will have a pid equal to its tid, which we get for
free from the kernel before clone returns.

The only time we'd actually have to make a getpid system call now is if
we take a signal during fork and the signal handler calls getpid. (That,
or we call getpid in the dynamic linker while it's still dealing with its
own relocations and hasn't even set up the main thread yet.)

Bug: 15387103
Change-Id: I6d4718ed0a5c912fc75b5f738c49a023dbed5189
4b558f50a42c97d461f1dede5aaaae490ea99e2e 05-Mar-2014 Elliott Hughes <enh@google.com> Rewrite the POSIX timer functions.

This is a much simpler implementation that lets the kernel
do as much as possible.

Co-authored-by: Jörgen Strand <jorgen.strand@sonymobile.com>
Co-authored-by: Snild Dolkow <snild.dolkow@sonymobile.com>
Change-Id: Iad19f155de977667aea09410266d54e63e8a26bf
36d6188f8cd8b948fb797f11d9620d63d0c2215a 19-Nov-2013 Elliott Hughes <enh@google.com> Clean up forking and cloning.

The kernel now maintains the pthread_internal_t::tid field for us,
and __clone was only used in one place so let's inline it so we don't
have to leave such a dangerous function lying around. Also rename
files to match their content and remove some useless #includes.

Change-Id: I24299fb4a940e394de75f864ee36fdabbd9438f9
877ec6d90418ff1d6597147d355a2229fdffae7e 16-Nov-2013 Elliott Hughes <enh@google.com> Fix pthread_join.

Let the kernel keep pthread_internal_t::tid updated, including
across forks and for the main thread. This then lets us fix
pthread_join to only return after the thread has really exited.

Also fix the thread attributes of the main thread so we don't
unmap the main thread's stack (which is really owned by the
dynamic linker and contains things like environment variables),
which fixes crashes when joining with an exited main thread
and also fixes problems reported publicly with accessing environment
variables after the main thread exits (for which I've added a new
unit test).

In passing I also fixed a bug where if the clone(2) inside
pthread_create(3) fails, we'd unmap the child's stack and TLS (which
contains the mutex) and then try to unlock the mutex. Boom! It wasn't
until after I'd uploaded the fix for this that I came across a new
public bug reporting this exact failure.

Bug: 8206355
Bug: 11693195
Bug: https://code.google.com/p/android/issues/detail?id=57421
Bug: https://code.google.com/p/android/issues/detail?id=62392
Change-Id: I2af9cf6e8ae510a67256ad93cad891794ed0580b
11952073af22568bba0b661f7a9d4402c443a888 25-Oct-2013 Elliott Hughes <enh@google.com> Remove dependencies on obsolete __ARCH_WANT_SYSCALL_DEPRECATED system calls.

(aarch64 kernels don't have these system calls.)

Change-Id: I6f64075aa412f71520f2df71c3d69b647f91c1ca
232163cf70712fe00436b70dd495f4cf405e9eab 10-Oct-2013 Elliott Hughes <enh@google.com> Clean up the cpuacct cruft.

Change-Id: I6ed63af8dfc2368e211420389fa8af4d5dc0908f