This change effectively adds the VFS side of support for the SO_LINGER
socket option, by allowing file descriptor close operations to be
suspended (and later resumed) by socket drivers. Currently, support
is limited to the close(2) system call--in all other cases where file
descriptors are closed (dup2, close-on-exec, process exit..), the
close operation still completes instantly. As a general policy, the
close(2) return value will always indicate that the file descriptor
has been closed: either 0, or -1 with errno set to EINPROGRESS. The
latter error may be thrown only when a suspended close is interrupted
by a signal.
As necessary for UDS, this change also introduces a closenb(2) system
call extension, allowing the caller to bypass blocking SO_LINGER close
behavior. This extension allows UDS to avoid blocking on closing the
last reference to an in-flight file descriptor, in an atomic fashion.
The extension is currently part of libsys, but there is no reason why
userland would not be allowed to make this call, so it is deliberately
not protected from use by userland.
Change-Id: Iec77d6665232110346180017fc1300b1614910b7
This patch adds the implementation of the BSD socket system calls
which have been introduced in an earlier patch. At the same time, it
adds support for communication with socket drivers, using a new
"socket device" (SDEV_) protocol. These two parts, implemented in
socket.c and sdev.c respectively, form the upper and lower halves of
the new BSD socket support in VFS. New mapping functionality for
socket domains and drivers is added as well, implemented in smap.c.
The rest of the changes mainly facilitate the separation of character
and socket driver calls, and do not make any fundamental alterations.
For example, while this patch changes VFS's select.c rather heavily,
the new select logic for socket drivers is the exact same as for
character drivers; the changes mainly separate the driver type
specific parts from the generic select logic further than before.
Change-Id: I2f13084dd3c8d3a68bfc69da0621120c8291f707
Previously, VFS would use various subsets of a number of fproc
structure fields to store state when the process is blocked
(suspended) for various reasons. As a result, there was a fair
amount of abuse of fields, hidden state, and confusion as to
which fields were used with which suspension states.
Instead, the suspension state is now split into per-state
structures, which are then stored in a union. Each of the union's
structures should be accessed only right before, during, and right
after the fp_blocked_on field is set to the corresponding blocking
type. As a result, it is now very clear which fields are in use
at which times, and we even save a bit of memory as a side effect.
Change-Id: I5c24e353b6cb0c32eb41c70f89c5cfb23f6c93df
By now it has become clear that the VFS select code has an unusually
high concentration of bugs, and there is no indication that any form
of convergence to a bug-free state is in sight. Thus, for now, it
may be helpful to be able to dump the contents of the select tables
in order to track down any bugs in the future. Hopefully that will
allow the next bugs to be resolved slightly after than before.
The debug dump can be triggered with "svrctl vfs get print_select".
Change-Id: Ia826746dce0f065d7f3b46aa9047945067b8263d
- About 80% of PM's process table consisted of per-signal sigaction
structures. This is information not used by the MIB service, and
can safely be stored outside the main process table.
- The MIB service does not need most of the VFS process table, so VFS
now generates a "light" version of its table upon request, with just
the fields used by the MIB service.
The result is a size reduction of the MIB service of about 700KB.
Change-Id: I79fe7239361fbfb45286af8e86a10aed4c2d2be7
- 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
The current values were both inaccurate (especially for dynamically
linked executables) and using the wrong unit (bytes, instead of
kilobytes times ticks-of-execution). For now we are better off not
populating these fields at all.
Change-Id: I195a8fa8db909e64a833eec25f59c9ee0b89bdc5
For dynamically linked executables, the interpreter is passed a
file descriptor of the binary being executed. To this end, VFS
opens the target executable, but opening the file fails if it is
not readable, even when it is executable. With this patch, when
opening the executable, it verifies the X bit rather than the R
bit on the file, thus allowing the execution of dynamically
linked binaries that are executable but not readable.
Add test86 to verify correctness.
Change-Id: If3514add6a33b33d52c05a0a627d757bff118d77
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
- synchronize request type with ioctl by making it unsigned long;
- unbreak VFS requests, as they were being sent to PM;
- use proper ioctl direction flags (and new numbers) for requests;
- remove some needless header inclusions;
- svrctl is in libc, make its message name reflect this;
- keep backward compatibility: svrctl is part of the userland ABI.
Change-Id: I44902e8d0d11b8ebc1ef3bda94d2202481743c9b
The remapping from /dev/tty to the real controlling terminal in the
device code was confusing the select code. The latter is now aware
of this case and should handle it properly, at the cost of one extra
field in the filp structure.
There is a nasty, hopefully sufficiently rare case of /dev/tty being
kept open while controlling terminals are changing, that we are still
not handling. Doing so would require more than just a few changes,
but the code should at least detect and cleanly fail on this case.
Test77 now has a basic test set for selecting on /dev/tty.
Change-Id: Iaedea449cdb728d0e66a9de8faacdfd9638dfe92
