This patch prepares for moving of the creation of socket files on the
file system from the libc bind(2) stub into the UDS service. This
change is necessary for the socket type agnostic libc implementation.
The change is not yet activated - the code that is not yet used is
enclosed in "#if NOT_YET" blocks. The activation needs to be atomic
with UDS's switch to libsockdriver; otherwise, user applications may
break.
As part of the change, various UDS bind(2) semantics are changed to
match the POSIX standard and other operating systems. In
implementation terms, the service-only VFS API checkperms(2) is
renamed to socketpath(2), and extended with a new subcall which
creates a new socket file. An extension to test56 checks the new
bind(2) semantics of UDS, although most new tests are still disabled
until activation as well.
Finally, as further preparation for a more structural redesign of the
UDS service, also return the <device,inode> number pair for the
created or checked file name, and make returning the canonized path
name optional.
Change-Id: I892d04b3301d4b911bdc571632ddde65fb747a8a
Currently, the BSD socket API is implemented in libc, translating the
API calls to character driver operations underneath. This approach
has several issues:
- it is inefficient, as most character driver operations are specific
to the socket type, thus requiring that each operation start by
bruteforcing the socket protocol family and type of the given file
descriptor using several system calls;
- it requires that libc itself be changed every time system support
for a new protocol is added;
- various parts of the libc implementations violate the asynchronous
signal safety POSIX requirements.
In order to resolve all these issues at once, the plan is to turn the
BSD socket calls into system calls, thus making the BSD socket API the
"native" ABI, removing the complexity from libc and instead letting
VFS deal with the socket calls.
The overall change is going to break all networking functionality. In
order to smoothen the transition, this patch introduces the fifteen
new BSD socket system calls, and makes libc try these first before
falling back on the old behavior. For now, the VFS implementations of
the new calls fail such that libc will always use the fallback cases.
Later on, when we introduce the actual implementation of the native
BSD socket calls, all statically linked programs will automatically
use the new ABI, thus limiting actual application breakage.
In other words: by itself, this patch does nothing, except add a bit
of transitional overhead that will disappear in the future. The
largest part of the patch is concerned with adding full support for
the new BSD socket system calls to trace(1) - this early addition has
the advantage of making system call tracing output of several socket
calls much more readable already.
Both the system call interfaces and the trace(1) support have already
been tested using code that will be committed later on.
Change-Id: I3460812be50c78be662d857f9d3d6840f3ca917f
- the userland call is now made to PM only, and PM relays the call to
other servers as appropriate; this is an ABI change that will
ultimately allow us to add proper support for wait3() and the like;
for the moment there is backward compatibility;
- the getrusage-specific kernel subcall has been removed, as it
provided only redundant functionality, and did not provide the means
to be extended correctly in the future - namely, allowing the kernel
to return different values depending on whether resource usage of
the caller (self) or its children was requested;
- VM is now told whether resource usage of the caller (self) or its
children is requested, and it refrains from filling in wrong values
for information it does not have;
- VM now uses the correct unit for the ru_maxrss values;
- VFS is cut out of the loop entirely, since it does not provide any
values at the moment; a comment explains how it should be readded.
Change-Id: I27b0f488437dec3d8e784721c67b03f2f853120f
There is no reason to keep these tightly coupled data structures
separate. Moreover, there is no reason to have a union of file
descriptor and file pointer, since the second can be derived from
the first. The result are somewhat cleaner VFS internals.
Change-Id: I854da7d8291177878eecfc3077ef0a9e0cc82aaa
