Under linux+cgo, OS threads are launched via pthread_create().
This abstraction, under linux, requires we avoid blocking
signals 32,33 and 34 indefinitely because they are needed to
reliably execute POSIX-semantics threading in glibc and/or musl.
When blocking signals the go runtime generally re-enables them
quickly. However, when a thread exits (under cgo, this is
via a return from mstart()), we avoid a deadlock in C-code by
not blocking these three signals.
Fixes#42494
Change-Id: I02dfb2480a1f97d11679e0c4b132b51bddbe4c14
Reviewed-on: https://go-review.googlesource.com/c/go/+/269799
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Trust: Tobias Klauser <tobias.klauser@gmail.com>
As part of #42026, these helpers from io/ioutil were moved to os.
(ioutil.TempFile and TempDir became os.CreateTemp and MkdirTemp.)
Update the Go tree to use the preferred names.
As usual, code compiled with the Go 1.4 bootstrap toolchain
and code vendored from other sources is excluded.
ReadDir changes are in a separate CL, because they are not a
simple search and replace.
For #42026.
Change-Id: If318df0216d57e95ea0c4093b89f65e5b0ababb3
Reviewed-on: https://go-review.googlesource.com/c/go/+/266365
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TestSetuidEtc() was failing sporadically on linux-ppc64. From the
three https://build.golang.org/ logs, it looked like the logged
errors could be associated with threads dying, but proc reads
were, in some way, racing with their demise.
Exploring ways to increase thread demise, revealed that races
of this type can happen on non-ppc64 systems, and that
os.IsNotExist(err) was not a sufficient error condition test
for a thread's status file disappearing. This change includes a
fix for that to.
The actual issue on linux-ppc64 appears to be tied to PID reaping
and reuse latency on whatever the build test environment is for
linux-ppc64-buildlet. I suspect this can happen on any linux
system, however, especially where the container has a limited PID
range.
The fix for this, limited to the test (the runtime syscall support
is unchanged), is to confirm that the Pid for the interrogated
thread's /proc/<TID>/status file confirms that it is still
associated with the test-process' PID.
linux-ppc64-buildlet:
go/bin/go test syscall -run=TestSetuidEtc -count=10000
ok syscall 104.285s
Fixes#42462
Change-Id: I55c84ab8361003570a405fa52ffec4949bf91113
Reviewed-on: https://go-review.googlesource.com/c/go/+/268717
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Tobias Klauser <tobias.klauser@gmail.com>
This change fixes two failng tests on linux-ppc64x:
- TestAllThreadsSyscall() exposed a real bug in the ppc64x support:
- It turns out that the r2 syscall return value is not defined
on all architectures. Notably linux-ppc64x so address that by
introducing a private architectural constant in the syscall
package, archHonorsR2: true if r2 has a determanistic value.
- TestSetuidEtc() was sensitive to /proc/<PID>/status content:
- The amount of padding space has changed with kernel vintage.
- Stress testing revealed a race with /proc files disappearing.
Fixes#42178
Change-Id: Ie6fc0b8f2f94a409ac0e5756e73bfce113274709
Reviewed-on: https://go-review.googlesource.com/c/go/+/266202
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
For some reason, currently unknown, this test case fails exclusively
on the linux-ppc64 platform. Until such time as it can be made to
work, we'll disable this test case on that platform.
The same issue causes TestSetuidEtc to fail too, so disable that
on this platform.
Updates #42178
Change-Id: Idd3f6c2ee9f2fba2eb8ce4de69de7f316858bb15
Reviewed-on: https://go-review.googlesource.com/c/go/+/264719
Trust: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change adds two new methods for invoking system calls
under Linux: syscall.AllThreadsSyscall() and
syscall.AllThreadsSyscall6().
These system call wrappers ensure that all OSThreads mirror
a common system call. The wrappers serialize execution of the
runtime to ensure no race conditions where any Go code observes
a non-atomic OS state change. As such, the syscalls have
higher runtime overhead than regular system calls, and only
need to be used where such thread (or 'm' in the parlance
of the runtime sources) consistency is required.
The new support is used to enable these functions under Linux:
syscall.Setegid(), syscall.Seteuid(), syscall.Setgroups(),
syscall.Setgid(), syscall.Setregid(), syscall.Setreuid(),
syscall.Setresgid(), syscall.Setresuid() and syscall.Setuid().
They work identically to their glibc counterparts.
Extensive discussion of the background issue addressed in this
patch can be found here:
https://github.com/golang/go/issues/1435
In the case where cgo is used, the C runtime can launch pthreads that
are not managed by the Go runtime. As such, the added
syscall.AllThreadsSyscall*() return ENOTSUP when cgo is enabled.
However, for the 9 syscall.Set*() functions listed above, when cgo is
active, these functions redirect to invoke their C.set*() equivalents
in glibc, which wraps the raw system calls with a nptl:setxid fixup
mechanism. This achieves POSIX semantics for these functions in the
combined Go and C runtime.
As a side note, the glibc/nptl:setxid support (2019-11-30) does not
extend to all security related system calls under Linux so using
native Go (CGO_ENABLED=0) and these AllThreadsSyscall*()s, where
needed, will yield more well defined/consistent behavior over all
threads of a Go program. That is, using the
syscall.AllThreadsSyscall*() wrappers for things like setting state
through SYS_PRCTL and SYS_CAPSET etc.
Fixes#1435
Change-Id: Ib1a3e16b9180f64223196a32fc0f9dce14d9105c
Reviewed-on: https://go-review.googlesource.com/c/go/+/210639
Trust: Emmanuel Odeke <emm.odeke@gmail.com>
Trust: Ian Lance Taylor <iant@golang.org>
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Austin Clements <austin@google.com>
The old os references are still valid, but update our code
to reflect best practices and get used to the new locations.
Code compiled with the bootstrap toolchain
(cmd/asm, cmd/dist, cmd/compile, debug/elf)
must remain Go 1.4-compatible and is excluded.
For #41190.
Change-Id: I8f9526977867c10a221e2f392f78d7dec073f1bd
Reviewed-on: https://go-review.googlesource.com/c/go/+/243907
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
On MIPS, Linux returns whether the syscall had an error in a separate
register (R7), not using a negative return value as on other
architectures. Thus, skip TestSyscallNoError as there is no error case
for syscall.RawSyscall which it could test against.
Also reformat the error output so the expected and gotten values are
aligned so they're easier to compare.
Fixes#35422
Change-Id: Ibc88f7c5382bb7ee8faf15ad4589ca1f9f017a06
Reviewed-on: https://go-review.googlesource.com/c/go/+/205898
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Check the size of uintptr instead of listing GOARCHes explicitly. This
will make the test also run on linux/mips{,le}.
Change-Id: I649f15d293002afc1360b1913910202c3e5188b7
Reviewed-on: https://go-review.googlesource.com/135715
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The system call geteuid can not work properly on android, which
causes a test case failed on rooted android/arm.
This CL disables the test case on android.
Fixes#27364
Change-Id: Ibfd33ef8cc1dfe8822c8be4280eae12ee30929c1
Reviewed-on: https://go-review.googlesource.com/132175
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
The Linux kernel faccessat system call does not take a flags parameter.
The flag parameter to the C library faccessat function is implemented in C.
The syscall.Faccessat function takes a flags parameter. In older releases
we have passed the flags parameter to the kernel, which ignored it.
In CL 120015 we started returning an error if any flags were set.
That seems clearly better than ignoring them, but it turns out that some
code was using the flags. The code was previously subtly broken.
Now it is obviously broken. That is better, but we can do better still:
we can implement the flags as the C library does. That is what this CL does.
Change-Id: I259bd6f240c3951e939b81c3032dead3d9c567b4
Reviewed-on: https://go-review.googlesource.com/126415
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
As mentioned in #25845, port CL 46474 from golang.org/x/sys/unix to the
syscall package.
Currently Linux' fchmodat(2) syscall implementation doesn't support the
flags parameter (though it might in future versions [1]). Fchmodat in
the syscall package takes the parameter and (wrongly) passes it on to the
syscall which will ignore it.
According to the POSIX.1-2008 manual page [2], AT_SYMLINK_NOFOLLOW is
the only valid value for the flags parameter and EOPNOTSUPP should be
returned in case changing the mode of a symbolic link is not supported
by the underlying system. EINVAL should be returned for any other value
of the flags parameter.
[1] https://patchwork.kernel.org/patch/9596301/
[2] http://pubs.opengroup.org/onlinepubs/9699919799/functions/chmod.html
Updates #20130
Updates #25845
Change-Id: I1021dd0e6a4f4cb3557cb1c1b34dd618c378cda6
Reviewed-on: https://go-review.googlesource.com/118658
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Error returns for linux/arm syscalls are handled since a long time.
Remove another list of unimplemented syscalls, following CL 96315.
The root-only check in TestSyscallNoError was shown to be sufficient as
part of CL 84485 already.
NetBSD and OpenBSD do not implement the sendfile syscall (yet), so add a
link to golang.org/issue/5847
Change-Id: I07efc3c3203537a4142707385f31b59dc0ecca42
Reviewed-on: https://go-review.googlesource.com/97115
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Add the rawSyscallNoError wrapper function which is used for Linux
syscalls that don't return an error and convert all applicable
occurences of RawSyscall to use it instead.
Fixes#22924
Change-Id: Iff1eddb54573d459faa01471f10398b3d38528dd
Reviewed-on: https://go-review.googlesource.com/84485
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Fix bug on Linux SysProcAttr handling: setting both Pdeathsig and
Credential caused Pdeathsig to be ignored. This is because the kernel
clears the deathsignal field when performing a setuid/setgid
system call.
Avoid this by moving Pdeathsig handling after Credential handling.
Fixes#9686
Change-Id: Id01896ad4e979b8c448e0061f00aa8762ca0ac94
Reviewed-on: https://go-review.googlesource.com/3290
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
