Set(String()) should be an idempotent operation. This is a useful property
which allows us to generate args while re-execing the same process. Setting
`--flag-name=val.String()` should work.
PiperOrigin-RevId: 552598313
This commit adds support for program execution via a host file
descriptor. To make use of this feature, the host file descriptor must
be provided to the --exec-fd argument. For example,
exec 3</usr/bin/echo
runsc exec --exec-fd=3 mycontainer hello world
will run the host's echo binary inside gVisor. In this case, "hello" is
supplied to echo as argv[0]. As a result, the output of the above
command is "world".
This feature is useful for bootstrapping unknown guest environments and
allows static executables to perform setup actions inside the container
while they need not be part of the guest file system.
GitHub pull request #8634 concluded that commit 9f521bd should be
merged. However, the changes since commit feb40ac got lost in merge
1f331d1. This commit is the lost diff.
This commit implements file descriptor passing from the host to the
guest. It implements a --pass-fd flag that can be specified multiple
times with FD numbers from the host that will be inserted into the file
descriptor table of the guest.
When a terminal is used, signals are now forwared to the foreground
process inside the sandbox. As a result, control commands like Ctrl+C
can be handled by the terminal in the guest.
Set stdio ownership based on the container's user to ensure the
user can open/read/write to/from stdios.
1. stdios in the host are changed to have the owner be the same
uid/gid of the process running the sandbox. This ensures that the
sandbox has full control over it.
2. stdios owner owner inside the sandbox is changed to match the
container's user to give access inside the container and make it
behave the same as runc.
Fixes#6180
PiperOrigin-RevId: 384347009
The syscall package has been deprecated in favor of golang.org/x/sys.
Note that syscall is still used in some places because the following don't seem
to have an equivalent in unix package:
- syscall.SysProcIDMap
- syscall.Credential
Updates #214
PiperOrigin-RevId: 361381490
This allows to find all containers inside a sandbox more efficiently.
This operation is required every time a container starts and stops,
and previously required loading *all* container state files to check
whether the container belonged to the sandbox.
Apert from being inneficient, it has caused problems when state files
are stale or corrupt, causing inavalability to create any container.
Also adjust commands `list` and `debug` to skip over files that fail
to load.
Resolves#5052
PiperOrigin-RevId: 348050637
When OOM score adjustment needs to be set, all the containers need to be
loaded to find all containers that belong to the sandbox. However, each
load signals the container to ensure it is still alive. OOM score
adjustment is set during creation and deletion of every container, generating
a flood of signals to all containers. The fix removes the signal check
when it's not needed.
There is also a race fetching OOM score adjustment value from the parent when
the sandbox exits at the same time (the time it took to signal containers above
made this window quite large). The fix is to store the original value
in the sandbox state file and use it when the value needs to be restored.
Also add more logging and made the existing ones more consistent to help with
debugging.
PiperOrigin-RevId: 340940799
'docker exec' was getting CAP_NET_RAW even when --net-raw=false
because it was not filtered out from when copying container's
capabilities.
PiperOrigin-RevId: 272260451
Go was going to change the behavior of SysProcAttr.Ctty such that it must be an
FD in the *parent* FD table:
https://go-review.googlesource.com/c/go/+/178919/
However, after some debate, it was decided that this change was too
backwards-incompatible, and so it was reverted.
https://github.com/golang/go/issues/29458
The behavior going forward is unchanged: the Ctty FD must be an FD in the
*child* FD table.
PiperOrigin-RevId: 255228476
An upcoming change in Go 1.13 [1] changes the semantics of the SysProcAttr.Ctty
field. Prior to the change, the FD must be an FD in the child process's FD
table (aka "post-shuffle"). After the change, the FD must be an FD in the
current process's FD table (aka "pre-shuffle").
To be compatible with both versions this CL introduces a new boolean
"CttyFdIsPostShuffle" which indicates whether a pre- or post-shuffle FD should
be provided. We use build tags to chose the correct one.
1: https://go-review.googlesource.com/c/go/+/178919/
PiperOrigin-RevId: 255015303
Containerd uses the last error message sent to the log to
print as failure cause for create/exec. This required a
few changes in the logging logic for runsc:
- cmd.Errorf/Fatalf: now writes a message with 'error'
level to containerd log, in addition to stderr and
debug logs, like before.
- log.Infof/Warningf/Fatalf: are not sent to containerd
log anymore. They are mostly used for debugging and not
useful to containerd. In most cases, --debug-log is
enabled and this avoids the logs messages from being
duplicated.
- stderr is not used as default log destination anymore.
Some commands assume stdio is for the container/process
running inside the sandbox and it's better to never use
it for logging. By default, logs are supressed now.
PiperOrigin-RevId: 251881815
clearStatus was added to allow detached execution to wait
on the exec'd process and retrieve its exit status. However,
it's not currently used. Both docker and gvisor-containerd-shim
wait on the "shim" process and retrieve the exit status from
there. We could change gvisor-containerd-shim to use waits, but
it will end up also consuming a process for the wait, which is
similar to having the shim process.
Closes#234
PiperOrigin-RevId: 251349490
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
Removed "error" and "failed to" prefix that don't add value
from messages. Adjusted a few other messages. In particular,
when the container fail to start, the message returned is easier
for humans to read:
$ docker run --rm --runtime=runsc alpine foobar
docker: Error response from daemon: OCI runtime start failed: <path> did not terminate sucessfully: starting container: starting root container [foobar]: starting sandbox: searching for executable "foobar", cwd: "/", $PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin": no such file or directory
Closes#77
PiperOrigin-RevId: 230022798
Change-Id: I83339017c70dae09e4f9f8e0ea2e554c4d5d5cd1
Terminal support in runsc relies on host tty file descriptors that are imported
into the sandbox. Application tty ioctls are sent directly to the host fd.
However, those host tty ioctls are associated in the host kernel with a host
process (in this case runsc), and the host kernel intercepts job control
characters like ^C and send signals to the host process. Thus, typing ^C into a
"runsc exec" shell will send a SIGINT to the runsc process.
This change makes "runsc exec" handle all signals, and forward them into the
sandbox via the "ContainerSignal" urpc method. Since the "runsc exec" is
associated with a particular container process in the sandbox, the signal must
be associated with the same container process.
One big difficulty is that the signal should not necessarily be sent to the
sandbox process started by "exec", but instead must be sent to the foreground
process group for the tty. For example, we may exec "bash", and from bash call
"sleep 100". A ^C at this point should SIGINT sleep, not bash.
To handle this, tty files inside the sandbox must keep track of their
foreground process group, which is set/get via ioctls. When an incoming
ContainerSignal urpc comes in, we look up the foreground process group via the
tty file. Unfortunately, this means we have to expose and cache the tty file in
the Loader.
Note that "runsc exec" now handles signals properly, but "runs run" does not.
That will come in a later CL, as this one is complex enough already.
Example:
root@:/usr/local/apache2# sleep 100
^C
root@:/usr/local/apache2# sleep 100
^Z
[1]+ Stopped sleep 100
root@:/usr/local/apache2# fg
sleep 100
^C
root@:/usr/local/apache2#
PiperOrigin-RevId: 215334554
Change-Id: I53cdce39653027908510a5ba8d08c49f9cf24f39
This makes `runsc wait` behave more like waitpid()/wait4() in that:
- Once a process has run to completion, you can wait on it and get its exit
code.
- Processes not waited on will consume memory (like a zombie process)
PiperOrigin-RevId: 213358916
Change-Id: I5b5eca41ce71eea68e447380df8c38361a4d1558
This is different from the existing -pid-file flag, which saves a host pid.
PiperOrigin-RevId: 212713968
Change-Id: I2c486de8dd5cfd9b923fb0970165ef7c5fc597f0
When no capabilities are specified in exec, use the
container's capabilities to match runc's behavior.
PiperOrigin-RevId: 211735186
Change-Id: Icd372ed64410c81144eae94f432dffc9fe3a86ce
Remove GetExecutablePath (the non-internal version). This makes path handling
more consistent between exec, root, and child containers.
The new getExecutablePath now uses MountNamespace.FindInode, which is more
robust than Walking the Dirent tree ourselves.
This also removes the last use of lstat(2) in the sentry, so that can be
removed from the filters.
PiperOrigin-RevId: 211683110
Change-Id: Ic8ec960fc1c267aa7d310b8efe6e900c88a9207a
This CL adds terminal support for "docker exec". We previously only supported
consoles for the container process, but not exec processes.
The SYS_IOCTL syscall was added to the default seccomp filter list, but only
for ioctls that get/set winsize and termios structs. We need to allow these
ioctl for all containers because it's possible to run "exec -ti" on a
container that was started without an attached console, after the filters
have been installed.
Note that control-character signals are still not properly supported.
Tested with:
$ docker run --runtime=runsc -it alpine
In another terminial:
$ docker exec -it <containerid> /bin/sh
PiperOrigin-RevId: 210185456
Change-Id: I6d2401e53a7697bb988c120a8961505c335f96d9
When "exec" command is called without the "--detach" flag, we spawn a second
"exec" command and wait for that one to start. We use the pid file passed in
--pid-file to detect when this second command has started running.
However if "exec" is called with no --pid-file flag, this system breaks down,
as we don't have a pid file to wait for.
This CL ensures that the second instance of the "exec" command always writes a
pid-file, so the wait is successful.
PiperOrigin-RevId: 206002403
Change-Id: If9f2be31eb6e831734b1b833f25054ec71ab94a6
Containers are created as processes in the sandbox. Of the many things that
don't work yet, the biggest issue is that the fsgofer is launched with its root
as the sandbox's root directory. Thus, when a container is started and wants to
read anything (including the init binary of the container), the gofer tries to
serve from sandbox's root (which basically just has pause), not the container's.
PiperOrigin-RevId: 201294560
Change-Id: I6423aa8830538959c56ae908ce067e4199d627b1
This is a necessary prerequisite for supporting multiple containers in a single
sandbox.
All the commands (in cmd package) now call operations on Containers (container
package). When a Container first starts, it will create a Sandbox with the same
ID.
The Sandbox class is now simpler, as it only knows how to create boot/gofer
processes, and how to forward commands into the running boot process.
There are TODOs sprinkled around for additional support for multiple
containers. Most notably, we need to detect when a container is intended to run
in an existing sandbox (by reading the metadata), and then have some way to
signal to the sandbox to start a new container. Other urpc calls into the
sandbox need to pass the container ID, so the sandbox can run the operation on
the given container. These are only half-plummed through right now.
PiperOrigin-RevId: 196688269
Change-Id: I1ecf4abbb9dd8987a53ae509df19341aaf42b5b0
Detachable exec commands are handled in the client entirely and the detach option is not used anymore.
PiperOrigin-RevId: 195181272
Change-Id: I6e82a2876d2c173709c099be59670f71702e5bf0
