* Aggregate architecture Overview in "What is gVisor?" as it makes more sense
in one place.
* Drop "user-space kernel" and use "application kernel". The term "user-space
kernel" is confusing when some platform implementation do not run in
user-space (instead running in guest ring zero).
* Clear up the relationship between the Platform page in the user guide and the
Platform page in the architecture guide, and ensure they are cross-linked.
* Restore the call-to-action quick start link in the main page, and drop the
GitHub link (which also appears in the top-right).
* Improve image formatting by centering all doc and blog images, and move the
image captions to the alt text.
PiperOrigin-RevId: 311845158
As per RFC 1122 and Linux retransmit timeout handling:
- The segment retransmit timeout needs to exponentially increase and
cap at a predefined value.
- TCP connection needs to timeout after a predefined number of
segment retransmissions.
- TCP connection should not timeout when the retranmission timeout
exceeds MaxRTO, predefined upper bound.
Fixes#2673
PiperOrigin-RevId: 311463961
This change adds support for TCP_SYNCNT and TCP_WINDOW_CLAMP options
in GetSockOpt/SetSockOpt. This change does not really change any
behaviour in Netstack and only stores/returns the stored value.
Actual honoring of these options will be added as required.
Fixes#2626, #2625
PiperOrigin-RevId: 311453777
Linux 4.18 and later make reads and writes coherent between pre-copy-up and
post-copy-up FDs representing the same file on an overlay filesystem. However,
memory mappings remain incoherent:
- Documentation/filesystems/overlayfs.rst, "Non-standard behavior": "If a file
residing on a lower layer is opened for read-only and then memory mapped with
MAP_SHARED, then subsequent changes to the file are not reflected in the
memory mapping."
- fs/overlay/file.c:ovl_mmap() passes through to the underlying FD without any
management of coherence in the overlay.
- Experimentally on Linux 5.2:
```
$ cat mmap_cat_page.c
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
int main(int argc, char **argv) {
if (argc < 2) {
errx(1, "syntax: %s [FILE]", argv[0]);
}
const int fd = open(argv[1], O_RDONLY);
if (fd < 0) {
err(1, "open(%s)", argv[1]);
}
const size_t page_size = sysconf(_SC_PAGE_SIZE);
void* page = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
if (page == MAP_FAILED) {
err(1, "mmap");
}
for (;;) {
write(1, page, strnlen(page, page_size));
if (getc(stdin) == EOF) {
break;
}
}
return 0;
}
$ gcc -O2 -o mmap_cat_page mmap_cat_page.c
$ mkdir lowerdir upperdir workdir overlaydir
$ echo old > lowerdir/file
$ sudo mount -t overlay -o "lowerdir=lowerdir,upperdir=upperdir,workdir=workdir" none overlaydir
$ ./mmap_cat_page overlaydir/file
old
^Z
[1]+ Stopped ./mmap_cat_page overlaydir/file
$ echo new > overlaydir/file
$ cat overlaydir/file
new
$ fg
./mmap_cat_page overlaydir/file
old
```
Therefore, while the VFS1 gofer client's behavior of reopening read FDs is only
necessary pre-4.18, replacing existing memory mappings (in both sentry and
application address spaces) with mappings of the new FD is required regardless
of kernel version, and this latter behavior is common to both VFS1 and VFS2.
Re-document accordingly, and change the runsc flag to enabled by default.
New test:
- Before this CL: https://source.cloud.google.com/results/invocations/5b222d2c-e918-4bae-afc4-407f5bac509b
- After this CL: https://source.cloud.google.com/results/invocations/f28c747e-d89c-4d8c-a461-602b33e71aab
PiperOrigin-RevId: 311361267
kernel.Task.Block() requires that the caller is running on the task goroutine.
netstack.SocketOperations.Write() uses kernel.TaskFromContext() to call
kernel.Task.Block() even if it's not running on the task goroutine. Stop doing
that.
PiperOrigin-RevId: 311178335
view.ToVectorisedView() now just returns an empty vectorised
view if the view is of zero length. Earlier it would return
a VectorisedView of zero length but with 1 empty view. This
has been a source of bugs as lower layers don't expect
zero length views in VectorisedViews.
VectorisedView.AppendView() now is a no-op if the view being
appended is of zero length.
Fixes#2658
PiperOrigin-RevId: 310942269
Some functions were added for Arm64 platform:
a, get_fp/set_fp
b, inline_tgkill
Test step:
bazel test //test/syscalls:fpsig_fork_test_runsc_ptrace
Signed-off-by: Bin Lu <bin.lu@arm.com>
Some code paths needed these syscalls anyways, so they should be included in
the filters. Given that we depend on these syscalls in some cases, there's no
real reason to avoid them any more.
PiperOrigin-RevId: 310829126
This has two effects: It makes flags passed to open("/proc/[pid]/fd/[hostfd]")
effective, and it prevents imported pipes/sockets/character devices from being
opened with O_NONBLOCK unconditionally (because the underlying host FD was set
to non-blocking in ImportFD()).
PiperOrigin-RevId: 310596062
Without this fix, make exits with zero code when bazel build failed:
$ make run TARGETS="--abra --kadabra"
ERROR: Unrecognized option: --abra
$ echo $?
0
Signed-off-by: Andrei Vagin <avagin@gmail.com>
This change two does things:
1) Name the container based on the canonical directory path.
2) Allow the container to exit after bazel itself has exited.
The first is necessary to support multiple working directories,
while the second one allows these instances to clean up properly.
PiperOrigin-RevId: 310460748
Only the last test was running before since the goroutines won't be executed
until after this loop. I added t.Log(test.name) and this is was the result:
TestListenNoAcceptNonUnicastV4/SourceUnspecified: DestOtherMulticast
TestListenNoAcceptNonUnicastV4/DestUnspecified: DestOtherMulticast
TestListenNoAcceptNonUnicastV4/DestOtherMulticast: DestOtherMulticast
TestListenNoAcceptNonUnicastV4/SourceBroadcast: DestOtherMulticast
TestListenNoAcceptNonUnicastV4/DestOurMulticast: DestOtherMulticast
TestListenNoAcceptNonUnicastV4/DestBroadcast: DestOtherMulticast
TestListenNoAcceptNonUnicastV4/SourceOtherMulticast: DestOtherMulticast
TestListenNoAcceptNonUnicastV4/SourceOurMulticast: DestOtherMulticast
https://github.com/golang/go/wiki/TableDrivenTests#parallel-testing
PiperOrigin-RevId: 310440629
Adin Scannell
Bhasker Hariharan
Jamie Liu
gVisor bot
Nicolas Lacasse
Mithun Iyer
Fabricio Voznika
Ian Gudger
Nayana Bidari
Kevin Krakauer
Bin Lu
Zeling Feng
Andrei Vagin
Sam Balana