The existing logic attempting to do this is incorrect. Unary ^ has
higher precedence than &^, so mask always has UnblockableSignals
cleared, allowing dequeueSignalLocked to dequeue unblockable signals
(which allows userspace to ignore them).
Switch the logic so that unblockable signals are always masked.
PiperOrigin-RevId: 244058487
Change-Id: Ib19630ac04068a1fbfb9dc4a8eab1ccbdb21edc3
FD limit and file size limit is read from the host, instead
of using hard-coded defaults, given that they effect the sandbox
process. Also limit the direct cache to use no more than half
if the available FDs.
PiperOrigin-RevId: 244050323
Change-Id: I787ad0fdf07c49d589e51aebfeae477324fe26e6
Current, doPoll copies the user struct pollfd array into a
[]syscalls.PollFD, which contains internal kdefs.FD and
waiter.EventMask types. While these are currently binary-compatible with
the Linux versions, we generally discourage copying directly to internal
types (someone may inadvertantly change kdefs.FD to uint64).
Instead, copy directly to a []linux.PollFD, which will certainly be
binary compatible. Most of syscalls/polling.go is included directly into
syscalls/linux/sys_poll.go, as it can then operate directly on
linux.PollFD. The additional syscalls.PollFD type is providing little
value.
I've also added explicit conversion functions for waiter.EventMask,
which creates the possibility of a different binary format.
PiperOrigin-RevId: 244042947
Change-Id: I24e5b642002a32b3afb95a9dcb80d4acd1288abf
Normal files display their path in the current mount namespace:
I0410 10:57:54.964196 216336 x:0] [ 1] ls X read(0x3 /proc/filesystems, 0x55cee3bdb2c0 "nodev\t9p\nnodev\tdevpts \nnodev\tdevtmpfs\nnodev\tproc\nnodev\tramdiskfs\nnodev\tsysfs\nnodev\ttmpfs\n", 0x1000) = 0x58 (24.462?s)
AT_FDCWD includes the CWD:
I0411 12:58:48.278427 1526 x:0] [ 1] stat_test E newfstatat(AT_FDCWD /home/prattmic, 0x55ea719b564e /proc/self, 0x7ef5cefc2be8, 0x0)
Sockets (and other non-vfs files) display an inode number (like
/proc/PID/fd):
I0410 10:54:38.909123 207684 x:0] [ 1] nc E bind(0x3 socket:[1], 0x55b5a1652040 {Family: AF_INET, Addr: , Port: 8080}, 0x10)
I also fixed a few syscall args that should be Path.
PiperOrigin-RevId: 243169025
Change-Id: Ic7dda6a82ae27062fe2a4a371557acfd6a21fa2a
RootFromContext can return a dirent with reference taken, or nil. We must call
DecRef if (and only if) a real dirent is returned.
PiperOrigin-RevId: 242965515
Change-Id: Ie2b7b4cb19ee09b6ccf788b71f3fd7efcdf35a11
DirentCache is already a savable type, and it ensures that it is empty at the
point of Save. There is no reason not to save it along with the MountSource.
This did uncover an issue where not all MountSources were properly flushed
before Save. If a mount point has an open file and is then unmounted, we save
the MountSource without flushing it first. This CL also fixes that by flushing
all MountSources for all open FDs on Save.
PiperOrigin-RevId: 242906637
Change-Id: I3acd9d52b6ce6b8c989f835a408016cb3e67018f
From sendfile spec and also the linux kernel code, we should
limit the count arg to 'MAX_RW_COUNT'. This patch export
'MAX_RW_COUNT' in kernel pkg and use it in the implementation
of sendfile syscall.
Signed-off-by: Li Qiang <pangpei.lq@antfin.com>
Change-Id: I1086fec0685587116984555abd22b07ac233fbd2
PiperOrigin-RevId: 242745831
We construct a ramfs tree of "scaffolding" directories for all mount points, so
that a directory exists that each mount point can be mounted over.
We were creating these directories without write permissions, which meant that
they were not wribable even when underlayed under a writable filesystem. They
should be writable.
PiperOrigin-RevId: 242507789
Change-Id: I86645e35417560d862442ff5962da211dbe9b731
Strings are a better fit for this usage because they are immutable in Go, and
can contain arbitrary bytes. It also allows us to avoid casting bytes to string
(and the associated allocation) in the hot path when checking for overlay
whiteouts.
PiperOrigin-RevId: 242208856
Change-Id: I7699ae6302492eca71787dd0b72e0a5a217a3db2
In particular, ns.IDOfTask and tg.ID are used for gettid and getpid,
respectively, where removing defer saves ~100ns. This may be a small
improvement to application logging, which may call gettid/getpid
frequently.
PiperOrigin-RevId: 242039616
Change-Id: I860beb62db3fe077519835e6bafa7c74cba6ca80
This will save copies when preemption is not caused by a CPU migration.
PiperOrigin-RevId: 241844399
Change-Id: I2ba3b64aa377846ab763425bd59b61158f576851
Dirent.exists() is called in Create to check whether a child with the given
name already exists.
Dirent.exists() calls walk(), and before this CL allowed walk() to drop d.mu
while calling d.Inode.Lookup. During this existence check, a racing Rename()
can acquire d.mu and create a new child of the dirent with the same name.
(Note that the source and destination of the rename must be in the same
directory, otherwise renameMu will be taken preventing the race.) In this
case, d.exists() can return false, even though a child with the same name
actually does exist.
This CL changes d.exists() so that it does not release d.mu while walking, thus
preventing the race with Rename.
It also adds comments noting that lockForRename may not take renameMu if the
source and destination are in the same directory, as this is a bit surprising
(at least it was to me).
PiperOrigin-RevId: 241842579
Change-Id: I56524870e39dfcd18cab82054eb3088846c34813
If there are thousands of threads, ThreadGroupsAppend becomes very
expensive as it must iterate over all Tasks to find the ThreadGroup
leaders.
Reduce the cost by maintaining a map of ThreadGroups which can be used
to grab them all directly.
The one somewhat visible change is to convert PID namespace init
children zapping to a group-directed SIGKILL, as Linux did in
82058d668465 "signal: Use group_send_sig_info to kill all processes in a
pid namespace".
In a benchmark that creates N threads which sleep for two minutes, we
see approximately this much CPU time in ThreadGroupsAppend:
Before:
1 thread: 0ms
1024 threads: 30ms - 9130ms
4096 threads: 50ms - 2000ms
8192 threads: 18160ms
16384 threads: 17210ms
After:
1 thread: 0ms
1024 threads: 0ms
4096 threads: 0ms
8192 threads: 0ms
16384 threads: 0ms
The profiling is actually extremely noisy (likely due to cache effects),
as some runs show almost no samples at 1024, 4096 threads, but obviously
this does not scale to lots of threads.
PiperOrigin-RevId: 241828039
Change-Id: I17827c90045df4b3c49b3174f3a05bca3026a72c
The previous implementation revolved around runes instead of bytes, which caused
weird behavior when converting between the two. For example, peekRune would read
the byte 0xff from a buffer, convert it to a rune, then return it. As rune is an
alias of int32, 0xff was 0-padded to int32(255), which is the hex code point for
?. However, peekRune also returned the length of the byte (1). When calling
utf8.EncodeRune, we only allocated 1 byte, but tried the write the 2-byte
character ?.
tl;dr: I apparently didn't understand runes when I wrote this.
PiperOrigin-RevId: 241789081
Change-Id: I14c788af4d9754973137801500ef6af7ab8a8727
Also makes the safemem reading and writing inline, as it makes it easier to see
what locks are held.
PiperOrigin-RevId: 241775201
Change-Id: Ib1072f246773ef2d08b5b9a042eb7e9e0284175c
Added syscall annotations for unimplemented syscalls for later generation into
reference docs. Annotations are of the form:
@Syscall(<name>, <key:value>, ...)
Supported args and values are:
- arg: A syscall option. This entry only applies to the syscall when given this
option.
- support: Indicates support level
- UNIMPLEMENTED: Unimplemented (implies returns:ENOSYS)
- PARTIAL: Partial support. Details should be provided in note.
- FULL: Full support
- returns: Indicates a known return value. Values are
syscall errors. This is treated as a string so you can use something
like "returns:EPERM or ENOSYS".
- issue: A Github issue number.
- note: A note
Example:
// @Syscall(mmap, arg:MAP_PRIVATE, support:FULL, note:Private memory fully supported)
// @Syscall(mmap, arg:MAP_SHARED, support:UNIMPLEMENTED, issue:123, note:Shared memory not supported)
// @Syscall(setxattr, returns:ENOTSUP, note:Requires file system support)
Annotations should be placed as close to their implementation as possible
(preferrably as part of a supporting function's Godoc) and should be updated as
syscall support changes.
PiperOrigin-RevId: 241697482
Change-Id: I7a846135db124e1271dc5057d788cba82ca312d4
Also remove comments in InodeOperations that required that implementation of
some Create* operations ensure that the name does not already exist, since
these checks are all centralized in the Dirent.
PiperOrigin-RevId: 241637335
Change-Id: Id098dc6063ff7c38347af29d1369075ad1e89a58
We weren't saving simple devices' last allocated inode numbers, which
caused inode number reuse across S/R.
PiperOrigin-RevId: 241414245
Change-Id: I964289978841ef0a57d2fa48daf8eab7633c1284
ilist:generic_list works faster (cl/240185278) and
the code looks cleaner without type casting.
PiperOrigin-RevId: 241381175
Change-Id: I8487ab1d73637b3e9733c253c56dce9e79f0d35f
We call NewSharedAnonMappable simply to use it for Mappable/MappingIdentity for
shared anon mmap. From MMapOpts.MappingIdentity: "If MMapOpts is used to
successfully create a memory mapping, a reference is taken on MappingIdentity."
mm.createVMALocked (below) takes this additional reference, so we don't need
the reference returned by NewSharedAnonMappable. Holding it leaks the mappable.
PiperOrigin-RevId: 241038108
Change-Id: I78ee3af78e0cc7aac4063b274b30d0e41eb5677d
When fork a child process, the name filed of TaskContext is not set.
It results in that when we cat /proc/{pid}/status, the name filed is
null.
Like this:
Name:
State: S (sleeping)
Tgid: 28
Pid: 28
PPid: 26
TracerPid: 0
FDSize: 8
VmSize: 89712 kB
VmRSS: 6648 kB
Threads: 1
CapInh: 00000000a93d35fb
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: 00000000a93d35fb
Seccomp: 0
Change-Id: I5d469098c37cedd19da16b7ffab2e546a28a321e
PiperOrigin-RevId: 240893304
- Document fsutil.CachedFileObject.FD() requirements on access
permissions, and change gofer.inodeFileState.FD() to honor them.
Fixes#147.
- Combine gofer.inodeFileState.readonly and
gofer.inodeFileState.readthrough, and simplify handle caching logic.
- Inline gofer.cachePolicy.cacheHandles into
gofer.inodeFileState.setSharedHandles, because users with access to
gofer.inodeFileState don't necessarily have access to the fs.Inode
(predictably, this is a save/restore problem).
Before this CL:
$ docker run --runtime=runsc-d -v $(pwd)/gvisor/repro:/root/repro -it ubuntu bash
root@34d51017ed67:/# /root/repro/runsc-b147
mmap: 0x7f3c01e45000
Segmentation fault
After this CL:
$ docker run --runtime=runsc-d -v $(pwd)/gvisor/repro:/root/repro -it ubuntu bash
root@d3c3cb56bbf9:/# /root/repro/runsc-b147
mmap: 0x7f78987ec000
o
PiperOrigin-RevId: 240818413
Change-Id: I49e1d4a81a0cb9177832b0a9f31a10da722a896b
The start time is the number of clock ticks between the boot time and
application start time.
PiperOrigin-RevId: 240619475
Change-Id: Ic8bd7a73e36627ed563988864b0c551c052492a5
This is the same technique used by Go's strings.Builder
(https://golang.org/src/strings/builder.go#L45), and for the same
reason. (We can't just use strings.Builder because there's no way to get
the underlying []byte to pass to usermem.IO.CopyIn.)
PiperOrigin-RevId: 240594892
Change-Id: Ic070e7e480aee53a71289c7c120850991358c52c
Memfds are simply anonymous tmpfs files with no associated
mounts. Also implementing file seals, which Linux only implements for
memfds at the moment.
PiperOrigin-RevId: 240450031
Change-Id: I31de78b950101ae8d7a13d0e93fe52d98ea06f2f
MM.insertPMAsLocked() passes vma.maxPerms to memmap.Mappable.Translate
(although it unsets AccessType.Write if the vma is private). This
somewhat simplifies handling of pmas, since it means only COW-break
needs to replace existing pmas. However, it also means that a MAP_SHARED
mapping of a file opened O_RDWR dirties the file, regardless of the
mapping's permissions and whether or not the mapping is ever actually
written to with I/O that ignores permissions (e.g.
ptrace(PTRACE_POKEDATA)).
To fix this:
- Change the pma-getting path to request only the permissions that are
required for the calling access.
- Change memmap.Mappable.Translate to take requested permissions, and
return allowed permissions. This preserves the existing behavior in the
common cases where the memmap.Mappable isn't
fsutil.CachingInodeOperations and doesn't care if the translated
platform.File pages are written to.
- Change the MM.getPMAsLocked path to support permission upgrading of
pmas outside of copy-on-write.
PiperOrigin-RevId: 240196979
Change-Id: Ie0147c62c1fbc409467a6fa16269a413f3d7d571
ilist:generic_list works faster than ilist:ilist.
Here is a beanchmark test to measure performance of epoll_wait, when readyList
isn't empty. It shows about 30% better performance with these changes.
Benchmark Time(ns) CPU(ns) Iterations
Before:
BM_EpollAllEvents 46725 46899 14286
After:
BM_EpollAllEvents 33167 33300 18919
PiperOrigin-RevId: 240185278
Change-Id: I3e33f9b214db13ab840b91613400525de5b58d18
Michael Pratt
Fabricio Voznika
Jamie Liu
Nicolas Lacasse
Yong He
Kevin Krakauer
Shiva Prasanth
Li Qiang
Bhasker Hariharan
Andrei Vagin
Adin Scannell
Ian Lewis
Rahat Mahmood
Wei Zhang
chris.zn
Bert Muthalaly
Googler