We're currently seeing how hard it would be to run CloudABI binaries on
operating systems cannot be modified easily (Windows, Mac OS X). The
idea is that we want to just run them without any sandboxing. Now
that CloudABI executables are PIE, this is already a bit easier, but TLS
is still problematic:
- CloudABI executables want to write to the %fs, which typically
requires extra system calls by the emulator every time it needs to
switch between CloudABI's and its own TLS.
- If CloudABI executables overwrite the %fs base unconditionally, it
also becomes harder for the emulator to store a backup of the old
value of %fs. To solve this, let's no longer overwrite %fs, but just
%fs:0.
As CloudABI's C library does not use a TCB, this space can now be used
by an emulator to keep track of its internal state. The executable can
now safely overwrite %fs:0, as long as it makes sure that the TCB is
copied over to the new TLS area.
Ensure that there is an initial TLS area set up when the process starts,
only containing a bogus TCB. We don't really care about its contents on
FreeBSD.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D5836
This is kinda critical to the performance when the CPU is slow and
network bandwidth is high, e.g. in the hypervisor.
Reviewed by: rrs, gallatin, Dexuan Cui <decui microsoft com>
Sponsored by: Microsoft OSTC
Differential Revision: https://reviews.freebsd.org/D5765
- Set BI_CAN_EXEC_DYN, so we can execute ET_DYN ELF files in addition to
regular ET_EXECs.
- Provide an AT_BASE entry in the auxiliary vector, so the executable
knows at which address it got loaded and can apply relocations.
Some time ago I made a change to merge together the memory scope
definitions used by mmap (MAP_{PRIVATE,SHARED}) and lock objects
(PTHREAD_PROCESS_{PRIVATE,SHARED}). Though that sounded pretty smart
back then, it's backfiring. In the case of mmap it's used with other
flags in a bitmask, but for locking it's an enumeration. As our plan is
to automatically generate bindings for other languages, that looks a bit
sloppy.
Change all of the locking functions to use separate flags instead.
Obtained from: https://github.com/NuxiNL/cloudabi
data (headers). Historically the size of the headers was not checked
against the socket buffer space. Application could easily overcommit the
socket buffer space.
With the new sendfile (r293439) the problem remained, but a KASSERT was
inserted that checked that amount of data written to the socket matches
its space. In case when size of headers is bigger that socket space,
KASSERT fires. Without INVARIANTS the new sendfile won't panic, but
would report incorrect amount of bytes sent.
o With this change, the headers copyin is moved down into the cycle, after
the sbspace() check. The uio size is trimmed by socket space there,
which fixes the overcommit problem and its consequences.
o The compatibility handling for FreeBSD 4 sendfile headers API is pushed
up the stack to syscall wrappers. This required a copy and paste of the
code, but in turn this allowed to remove extra stack carried parameter
from fo_sendfile_t, and embrace entire compat code into #ifdef. If in
future we got more fo_sendfile_t function, the copy and paste level would
even reduce.
Reviewed by: emax, gallatin, Maxim Dounin <mdounin mdounin.ru>
Tested by: Vitalij Satanivskij <satan ukr.net>
Sponsored by: Netflix
The type definitions and constants that were used by COMPAT_CLOUDABI64
are a literal copy of some headers stored inside of CloudABI's C
library, cloudlibc. What is annoying is that we can't make use of
cloudlibc's system call list, as the format is completely different and
doesn't provide enough information. It had to be synced in manually.
We recently decided to solve this (and some other problems) by moving
the ABI definitions into a separate file:
https://github.com/NuxiNL/cloudabi/blob/master/cloudabi.txt
This file is processed by a pile of Python scripts to generate the
header files like before, documentation (markdown), but in our case more
importantly: a FreeBSD system call table.
This change discards the old files in sys/contrib/cloudabi and replaces
them by the latest copies, which requires some minor changes here and
there. Because cloudabi.txt also enforces consistent names of the system
call arguments, we have to patch up a small number of system call
implementations to use the new argument names.
The new header files can also be included directly in FreeBSD kernel
space without needing any includes/defines, so we can now remove
cloudabi_syscalldefs.h and cloudabi64_syscalldefs.h. Patch up the
sources to include the definitions directly from sys/contrib/cloudabi
instead.
1. Limit secs to INT32_MAX / 2 to avoid errors from kern_setitimer().
Assert that kern_setitimer() returns 0.
Remove bogus cast of secs.
Fix style(9) issues.
2. Increment the return value if the remaining tv_usec value more than 500000 as a Linux does.
Pointed out by: [1] Bruce Evans
MFC after: 1 week
On some architectures, u_long isn't large enough for resource definitions.
Particularly, powerpc and arm allow 36-bit (or larger) physical addresses, but
type `long' is only 32-bit. This extends rman's resources to uintmax_t. With
this change, any resource can feasibly be placed anywhere in physical memory
(within the constraints of the driver).
Why uintmax_t and not something machine dependent, or uint64_t? Though it's
possible for uintmax_t to grow, it's highly unlikely it will become 128-bit on
32-bit architectures. 64-bit architectures should have plenty of RAM to absorb
the increase on resource sizes if and when this occurs, and the number of
resources on memory-constrained systems should be sufficiently small as to not
pose a drastic overhead. That being said, uintmax_t was chosen for source
clarity. If it's specified as uint64_t, all printf()-like calls would either
need casts to uintmax_t, or be littered with PRI*64 macros. Casts to uintmax_t
aren't horrible, but it would also bake into the API for
resource_list_print_type() either a hidden assumption that entries get cast to
uintmax_t for printing, or these calls would need the PRI*64 macros. Since
source code is meant to be read more often than written, I chose the clearest
path of simply using uintmax_t.
Tested on a PowerPC p5020-based board, which places all device resources in
0xfxxxxxxxx, and has 8GB RAM.
Regression tested on qemu-system-i386
Regression tested on qemu-system-mips (malta profile)
Tested PAE and devinfo on virtualbox (live CD)
Special thanks to bz for his testing on ARM.
Reviewed By: bz, jhb (previous)
Relnotes: Yes
Sponsored by: Alex Perez/Inertial Computing
Differential Revision: https://reviews.freebsd.org/D4544
- Mark AIO system calls as STD and remove the helpers to dynamically
register them.
- Use COMPAT6 for the old system calls with the older sigevent instead of
an 'o' prefix.
- Simplify the POSIX configuration to note that AIO is always available.
- Handle AIO in the default VOP_PATHCONF instead of special casing it in
the pathconf() system call. fpathconf() is still hackish.
- Remove freebsd32_aio_cancel() as it just called the native one directly.
Reviewed by: kib
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D5589
is always successfull.
So, ignore any errors and return 0 as a Linux do.
XXX. Unlike POSIX, Linux in case when the invalid seconds value specified
always return 0, so in that case Linux does not return proper remining time.
MFC after: 1 week
- Set td_errno so that ktrace and dtrace can obtain the syscall error
number in the usual way.
- Pass negative error numbers directly to the syscall layer, as they're
not intended to be returned to userland.
Reviewed by: kib
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D5425
- Make the system call fail if prot contains bits other than read, write
and exec.
- Similar to OpenBSD's W^X, don't allow write and exec to be set at the
same time. I'd like to see for now what happens if we enforce this
policy unconditionally. If it turns out that this is far too strict,
we'll loosen this requirement.
need to include it explicitly when <vm/vm_param.h> is already included.
Suggested by: alc
Reviewed by: alc
Differential Revision: https://reviews.freebsd.org/D5379
fork1 required its callers to pass a pointer to struct proc * which would
be set to the new process (if any). procdesc and racct manipulation also
used said pointer.
However, the process could have exited prior to do_fork return and be
automatically reaped, thus making this a use-after-free.
Fix the problem by letting callers indicate whether they want the pid or
the struct proc, return the process in stopped state for the latter case.
Reviewed by: kib
- Add some new hlist macros.
- Update existing hlist macros removing the need for a temporary
iteration variable.
- Properly define the RCU hlist macros to be SMP safe with regard
to RCU.
- Safe list macro arguments by adding a pair of parentheses.
- Prefix the _list_add() and _list_splice() functions with "linux"
to reflect they are LinuxKPI internal functions.
Obtained from: Linux
MFC after: 1 week
Sponsored by: Mellanox Technologies
- Fix implementation of atomic_add_unless(). The atomic_cmpset_int()
function returns a boolean and not the previous value of the atomic
variable.
- The atomic counters should be signed according to Linux.
- Some minor cosmetics and styling while at it.
Reviewed by: alfred @
MFC after: 1 week
Sponsored by: Mellanox Technologies
idr_alloc_cyclic() in the LinuxKPI. Bump the FreeBSD version to
force recompilation of all KLDs due to IDR structure size change.
MFC after: 2 weeks
Sponsored by: Mellanox Technologies
If a driver's Linux mmap callback passed vm_page_prot through unchanged,
then linux_dev_mmap_single() would try to apply whatever VM_MEMATTR_xxx
value 0 is to the mapping. On x86, VM_MEMATTR_DEFAULT is the PAT value
for write-back (WB) which is 6, while 0 maps to the PAT value for
uncacheable (UC). Thus, any mmap request that did not explicitly set
page_prot was tried to map memory as UC triggering the warning in
sg_pager_getpages().
Tested by: np
Reported by: Krishnamraju Eraparaju @ Chelsio
MFC after: 3 days
Sponsored by: Chelsio Communications
LinuxKPI. Fix a few spaces to tabs. Bump the FreeBSD version to force
recompilation of existing KMODs.
MFC after: 1 week
Sponsored by: Mellanox Technologies
and replace crcopysafe by crcopy as crcopysafe is is not intended to be
safe in a threaded environment, it drops PROC_LOCK() in while() that
can lead to unexpected results, such as overwrite kernel memory.
In my POV crcopysafe() needs special attention. For now I do not see
any problems with this function, but who knows.
Submitted by: dchagin
Found by: trinity
Security: SA-16:04.linux
The set_robust_list system call request the kernel to record the head
of the list of robust futexes owned by the calling thread. The head
argument is the list head to record.
The get_robust_list system call should return the head of the robust
list of the thread whose thread id is specified in pid argument.
The list head should be stored in the location pointed to by head
argument.
In contrast, our implemenattion of get_robust_list system call copies
the known portion of memory pointed by recorded in set_robust_list
system call pointer to the head of the robust list to the location
pointed by head argument.
So, it is possible for a local attacker to read portions of kernel
memory, which may result in a privilege escalation.
Submitted by: mjg
Security: SA-16:03.linux
- Properly prefix internal functions with "linux_" instead of only a
single underscore to avoid future namespace collisions.
- Make some functions global instead of inline to ease debugging and
to avoid unnecessary code duplication.
- Remove no longer existing kthread_create() function's prototype.
MFC after: 1 week
Sponsored by: Mellanox Technologies
- Declare some static functions in linux_compat.c instead if inside
various header files.
- Prefix FreeBSD local functions in the LinuxKPI with "linux_" to
avoid symbol name conflicts in the future and to make debugging
easier.
- Make the "struct kobj_ktype" declaractions constant to shave off a
few bytes from the data segment.
MFC after: 1 week
Sponsored by: Mellanox Technologies
LinuxKPI. Compute string length before allocating memory instead of
using fixed size allocations. Make kobject_set_name_vargs() global
instead of inline to save some bytes when compiling.
MFC after: 1 week
Sponsored by: Mellanox Technologies
from taskqueue_enqueue() instead of reading "ta_pending" unlocked and
also ensure the callout is stopped before proceeding.
MFC after: 1 week
Sponsored by: Mellanox Technologies
- Use SDT_PROBE<N>() instead of SDT_PROBE(). This has no functional effect
at the moment, but will be needed for some future changes.
- Don't hardcode the module component of the probe identifier. This is
set automatically by the SDT framework.
MFC after: 1 week
sysent.
sv_prepsyscall is unused.
sv_sigsize and sv_sigtbl translate signal number from the FreeBSD
namespace into the ABI domain. It is only utilized on i386 for iBCS2
binaries. The issue with this approach is that signals for iBCS2 were
delivered with the FreeBSD signal frame layout, which does not follow
iBCS2. The same note is true for any other potential user if
sv_sigtbl. In other words, if ABI needs signal number translation, it
really needs custom sv_sendsig method instead.
Sponsored by: The FreeBSD Foundation
sysentvec. This allows the timekeep data to be shared between similar
ABIs which cannot share sysentvec.
Make the timekeep_push_vdso() tick callback to the timekeep structures
instead of sysentvecs. If several sysentvec share the vdso_sv_tk
structure, we would update the userspace data several times on each
tick, without the change.
Only allocate vdso_sv_tk in the exec_sysvec_init() sysinit when
sysentvec is marked with the new SV_TIMEKEEP flag. This saves
allocation and update of unneeded vdso_sv_tk for ABIs which do not
provide userspace gettimeofday yet, which are PowerPCs arches right
now.
Make vdso_sv_tk allocator public, namely split out and export
alloc_sv_tk() and alloc_sv_tk_compat32(). ABIs which share timekeep
data now can allocate it manually and share as appropriate.
Requested by: nwhitehorn
Tested by: nwhitehorn, pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
- Add some missing I/O functions for non-i386 and amd64 platforms.
- Stub ioremap() to NULL using a macro to ensure non-existing memory
attributes are not referred when they do not exist.
- Add more header files to linux/list.h to resolve driver compilation
issues on Sparc64 and PowerPC platforms.
Sponsored by: Mellanox Technologies
The code compiles fine under Clang, but GCC on PPC is less permissive about
integer and pointer sizes. (An intmax_t is clearly *large enough* to hold a
pointer value.)
Another follow-up to r290475.
Reported by: jhibbits
Sponsored by: EMC / Isilon Storage Division
- Move all files related to the LinuxKPI into sys/compat/linuxkpi and
its subfolders.
- Update sys/conf/files and some Makefiles to use new file locations.
- Added description of COMPAT_LINUXKPI to sys/conf/NOTES which in turn
adds the LinuxKPI to all LINT builds.
- The LinuxKPI can be added to the kernel by setting the
COMPAT_LINUXKPI option. The OFED kernel option no longer builds the
LinuxKPI into the kernel. This was done to keep the build rules for
the LinuxKPI in sys/conf/files simple.
- Extend the LinuxKPI module to include support for USB by moving the
Linux USB compat from usb.ko to linuxkpi.ko.
- Bump the FreeBSD_version.
- A universe kernel build has been done.
Reviewed by: np @ (cxgb and cxgbe related changes only)
Sponsored by: Mellanox Technologies
In order to make it easier to support CloudABI on ARM64, move out all of
the bits from the AMD64 cloudabi_sysvec.c into a new file
cloudabi_module.c that would otherwise remain identical. This reduces
the AMD64 specific code to just ~160 lines.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D3974
CloudABI has approximately 50 system calls that do not depend on the
pointer size of the system. As the ABI is pretty compact, it takes
little effort to each truss(8) the formatting rules for these system
calls. Start off by formatting pointer size independent system calls.
Changes:
- Make it possible to include the CloudABI system call definitions in
FreeBSD userspace builds. Add ${root}/sys to the truss(8) Makefile so
we can pull in <compat/cloudabi/cloudabi_syscalldefs.h>.
- Refactoring: patch up amd64-cloudabi64.c to use the CLOUDABI_*
constants instead of rolling our own table.
- Add table entries for all of the system calls.
- Add new generic formatting types (UInt, IntArray) that we'll be using
to format unsigned integers and arrays of integers.
- Add CloudABI specific formatting types.
Approved by: jhb
Differential Revision: https://reviews.freebsd.org/D3836
r161611 added some of the code from sys_vfork() directly into the Linux
module wrappers since they use RFSTOPPED. In r232240, the RFFPWAIT handling
was moved to syscallret(), thus this code in the Linux module is no longer
needed as it will be called later.
This also allows the Linux wrappers to benefit from the fix in r275616 for
threads not getting suspended if their vforked child is stopped while they
wait on them.
Reviewed by: jhb, kib
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D3828
SDT_PROBE requires 5 parameters whereas SDT_PROBE<n> requires n parameters
where n is typically smaller than 5.
Perhaps SDT_PROBE should be made a private implementation detail.
MFC after: 20 days
To make it easier to understand how Capsicum interacts with linkat() and
renameat(), rename the rights to CAP_{LINK,RENAME}AT_{SOURCE,TARGET}.
This also addresses a shortcoming in Capsicum, where it isn't possible
to disable linking to files stored in a directory. Creating hardlinks
essentially makes it possible to access files with additional rights.
Reviewed by: rwatson, wblock
Differential Revision: https://reviews.freebsd.org/D3411
There is still one TODO item for these calls: add file descriptor
passing. The data structures are already prepared for this. It's just
the translation that's missing.
Obtained from: http://github.com/NuxiNL/freebsd
The cloudlibc pdwait() function ends up using FreeBSD's kqueue() in
combination with EVFILT_PROCDESC. This depends on CAP_EVENT -- not
CAP_PDWAIT.
Obtained from: https://github.com/NuxiNL/freebsd
Blocking on locks and condition variables can be accomplished by polling
and using the special filters CONDVAR, LOCK_RDLOCK and LOCK_WRLOCK.
For now it wouldn't make sense to implement this functionality into
kqueue() itself, for the reason that they are CloudABI specific and
would require us to resize 'struct kevent' to hold all of the parameters
of interest.
Add a bandaid to the CloudABI poll system call to call into the futex
code directly if it detects specific combinations of events that are
used by the C library.
Obtained from: https://github.com/NuxiNL/freebsd
This change implements two functions, cloudabi64_kevent_copyin() and
cloudabi64_kevent_copyout(), that convert CloudABI structures to
FreeBSD's struct kevent. CloudABI uses two structures: subscription_t
and event_t. The former is used for input, whereas the latter is used
for output. Unlike struct kevent, fields aren't overloaded for multiple
purposes or for separate event types.
For poll() we call into the newly introduced kern_kevent_anonymous()
function that allows us to poll without a file descriptor. This function
is not only used by poll(), but also by functions such as
sleep() and clock_nanosleep().
Reviewed by: jmg
Obtained from: https://github.com/NuxiNL/freebsd
Differential Revision: https://reviews.freebsd.org/D3308
If CloudABI processes open files with a set of requested rights that do
not match any of the privileges granted by O_RDONLY, O_WRONLY or O_RDWR,
we'd better fall back to O_RDONLY -- not O_WRONLY.
CloudABI purely operates on file descriptor rights (CAP_*). File
descriptor access modes (O_ACCMODE) are emulated on top of rights.
Instead of accepting the traditional flags argument, file_open() copies
in an fdstat_t object that contains the initial rights the descriptor
should have, but also file descriptor flags that should persist after
opening (APPEND, NONBLOCK, *SYNC). Only flags that don't persist (EXCL,
TRUNC, CREAT, DIRECTORY) are passed in as an argument.
file_open() first converts the rights, the persistent flags and the
non-persistent flags to fflags. It then calls into vn_open(). If
successful, it installs the file descriptor with the requested
rights, trimming off rights that don't apply to the type of
the file that has been opened.
Unlike kern_openat(), this function does not support /dev/fd/*. I can't
think of a reason why we need to support this for CloudABI.
Obtained from: https://github.com/NuxiNL/freebsd
Differential Revision: https://reviews.freebsd.org/D3235
It looks like a MODULE_VERSION() can also appear on its own -- there is
no need to use explicitly use DECLARE_MODULE(). Looking at other
modules, this seems common practice.
This kernel module does not require any explicit initialization, but a
module declaration is needed to let the "cloudabi64" kernel module
automatically pull this in.
Obtained from: https://github.com/NuxiNL/freebsd
The stat_put() system call can be used to modify file descriptor
attributes, such as flags, but also Capsicum permission bits. Support
for changing Capsicum bits will be added as soon as its dependent
changes have been pushed through code review.
Obtained from: https://github.com/NuxiNL/freebsd
CloudABI uses a structure called cloudabi_sockstat_t. Think of it as
'struct stat' for sockets. It is used by functions such as
getsockname(), getpeername(), some of the getsockopt() values, etc.
This change implements the sock_stat_get() system call that returns a
copy of this structure. The accept() system call should also return a
full copy of this structure eventually, but for now we're only
interested in the peer address. Add a TODO() to make sure this is
patched up later on.
Differential Revision: https://reviews.freebsd.org/D3218
On CloudABI we want to create file descriptors with just the minimal set
of Capsicum rights in place. The reason for this is that it makes it
easier to obtain uniform behaviour across different operating systems.
By explicitly whitelisting the operations, we can return consistent
error codes, but also prevent applications from depending OS-specific
behaviour.
Extend kern_kqueue() to take an additional struct filecaps that is
passed on to falloc_caps(). Update the existing consumers to pass in
NULL.
Differential Revision: https://reviews.freebsd.org/D3259
Summary:
Use the newly created `kern_shm_open()` function to create objects with
just the rights that are actually needed.
Reviewers: jhb, kib
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3260
On CloudABI, the rights bits returned by cap_rights_get() match up with
the operations that you can actually perform on the file descriptor.
Limiting the rights is good, because it makes it easier to get uniform
behaviour across different operating systems. If process descriptors on
FreeBSD would suddenly gain support for any new file operation, this
wouldn't become exposed to CloudABI processes without first extending
the rights.
Extend fork1() to gain a 'struct filecaps' argument that allows you to
construct process descriptors with custom rights. Use this in
cloudabi_sys_proc_fork() to limit the rights to just fstat() and
pdwait().
Obtained from: https://github.com/NuxiNL/freebsd
Summary:
Pipes in CloudABI are unidirectional. The reason for this is that
CloudABI attempts to provide a uniform runtime environment across
different flavours of UNIX.
Instead of implementing a custom pipe that is unidirectional, we can
simply reuse Capsicum permission bits to support this. This is nice,
because CloudABI already attempts to restrict permission bits to
correspond with the operations that apply to a certain file descriptor.
Replace kern_pipe() and kern_pipe2() by a single kern_pipe() that takes
a pair of filecaps. These filecaps are passed to the newly introduced
falloc_caps() function that creates the descriptors with rights in
place.
Test Plan:
CloudABI pipes seem to be created with proper rights in place:
https://github.com/NuxiNL/cloudlibc/blob/master/src/libc/unistd/pipe_test.c#L44
Reviewers: jilles, mjg
Reviewed By: mjg
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3236
CloudABI's openat() ensures that files are opened with the smallest set
of relevant rights. For example, when opening a FIFO, unrelated rights
like CAP_RECV are automatically removed. To remove unrelated rights, we
can just reuse the code for this that was already present in the rights
conversion function.
Summary:
CloudABI's readdir() system call could be thought of as a mixture
between FreeBSD's getdents(2) and pread(). Instead of using the file
descriptor offset, userspace provides a 64-bit cloudabi_dircookie_t
continue reading at a given point. CLOUDABI_DIRCOOKIE_START, having
value 0, can be used to return entries at the start of the directory.
The file descriptor offset is not used to store the cookie for the
reason that in a file descriptor centric environment, it would make
sense to allow concurrent use of a single file descriptor.
The remaining space returned by the system call should be filled with a
partially truncated copy of the next entry. The advantage of doing this
is that it gracefully deals with long filenames. If the C library
provides a buffer that is too small to hold a single entry, it can still
extract the directory entry header, meaning that it can retry the read
with a larger buffer or skip it using the cookie.
Test Plan:
This implementation passes the cloudlibc unit tests at:
https://github.com/NuxiNL/cloudlibc/tree/master/src/libc/dirent
Reviewers: marcel, kib
Reviewed By: kib
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3226
CloudABI uses a system call interface to modify file attributes that is
more similar to KPI's/FUSE, namely where a stat structure is passed back
to the kernel, together with a bitmask of attributes that should be
changed. This would allow us to update any set of attributes atomically.
That said, I'd rather not go as far as to actually implement it that
way, as it would require us to duplicate more code than strictly needed.
Let's just stick to the combinations that are actually used by
cloudlibc.
Obtained from: https://github.com/NuxiNL/freebsd
The file_create() system call can be used to create files of a given
type. Right now it can only be used to create directories and FIFOs. As
CloudABI does not expose filesystem permissions, this system call lacks
a mode argument. Simply use 0777 or 0666 depending on the file type.
Summary:
CloudABI provides access to two different stat structures:
- fdstat, containing file descriptor level status: oflags, file
descriptor type and Capsicum rights, used by cap_rights_get(),
fcntl(F_GETFL), getsockopt(SO_TYPE).
- filestat, containing your regular file status: timestamps, inode
number, used by fstat().
Unlike FreeBSD's stat::st_mode, CloudABI file descriptor types don't
have overloaded meanings (e.g., returning S_ISCHR() for kqueues). Add a
utility function to extract the type of a file descriptor accurately.
CloudABI does not work with O_ACCMODEs. File descriptors have two sets
of Capsicum-style rights: rights that apply to the file descriptor
itself ('base') and rights that apply to any new file descriptors
yielded through openat() ('inheriting'). Though not perfect, we can
pretty safely decompose Capsicum rights to such a pair. This is done in
convert_capabilities().
Test Plan: Tests for these system calls are fairly extensive in cloudlibc.
Reviewers: jonathan, mjg, #manpages
Reviewed By: mjg
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3171
Summary:
CloudABI provides two different types of futex objects: read-write locks
and condition variables. There is no need to provide separate support
for once objects and thread joining, as these are efficiently simulated
by blocking on a read-write lock. Mutexes simply use read-write locks.
Condition variables always have a lock object associated to them. They
always know to which lock a thread needs to be migrated if woken up.
This allows us to implement requeueing. A broadcast on a condition
variable will never cause multiple threads to be woken up at once. They
will be woken up iteratively.
This implementation still has lots of room for improvement. Locking is
coarse and right now we use linked lists to store all of the locks and
condition variables, instead of using a hash table. The primary goal of
this implementation was to behave correctly. Performance will be
improved as we go.
Test Plan:
This futex implementation has been in use for the last couple of months
and seems to work pretty well. All of the cloudlibc and libc++ unit
tests seem to pass.
Reviewers: dchagin, kib, vangyzen
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3148
Futex object scopes have been renamed from using their own constants to
simply reusing the existing CLOUDABI_MAP_{PRIVATE,SHARED} flags, as they
are more accurate in this context.
Summary:
Unlike FreeBSD, CloudABI does not use null terminated strings for its
pathnames. Introduce a function called copyin_path() that can be used by
all of the filesystem system calls that use pathnames. This change
already implements the system calls that don't depend on any additional
functionality (e.g., conversion of struct stat).
Also implement the socket system calls that operate on pathnames, namely
the ones used by the C library functions bindat() and connectat(). These
don't receive a 'struct sockaddr_un', but just the pathname, meaning
they could be implemented in such a way that they don't depend on the
size of sun_path. For now, just use the existing interfaces.
Add a missing #include to cloudabi_syscalldefs.h to get this code to
build, as one of its macros depends on UINT64_C().
Test Plan:
These implementations have already been tested in the CloudABI branch on
GitHub. They pass all of the tests.
Reviewers: kib, pjd
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3097
Though the standard C library uses a 'struct timespec' using a 64-bit
'time_t', there is no need to use such a type at the system call level.
CloudABI uses a simple 64-bit unsigned timestamp in nanoseconds. This is
sufficient to express any time value from 1970 to 2554.
The CloudABI low-level interface also supports fetching timestamp values
with a lower precision. Instead of overloading the clock ID argument for
this purpose, the system call provides a precision argument that may be
used to specify the maximum slack. The current system call
implementation does not use this information, but it's good to already
have this available.
Expose cloudabi_convert_timespec(), as we're going to need this for
fstat() as well.
Obtained from: https://github.com/NuxiNL/freebsd
Summary:
Remove the stub system call that was put in place during the system call
import and replace it by a target-dependent version stored in sys/amd64.
Initialize the thread in a way similar to cpu_set_upcall_kse(). We
provide the entry point with two arguments: the thread ID and the
argument pointer.
Test Plan:
Thread creation still seems to work, both for FreeBSD and CloudABI
binaries.
Reviewers: dchagin, mjg, kib
Reviewed By: kib
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3110
Just like FreeBSD+Capsicum, CloudABI uses process descriptors. Return
the file descriptor number to the parent process.
To the child process we both return a special value for the file
descriptor number (CLOUDABI_PROCESS_CHILD). We also return the thread ID
of the new thread in the copied process, so the threading library can
reinitialize itself.
Obtained from: https://github.com/NuxiNL/freebsd
SIGCHLD signal, should keep full 32 bits of the status passed to the
_exit(2).
Split the combined p_xstat of the struct proc into the separate exit
status p_xexit for normal process exit, and signalled termination
information p_xsig. Kernel-visible macro KW_EXITCODE() reconstructs
old p_xstat from p_xexit and p_xsig. p_xexit contains complete status
and copied out into si_status.
Requested by: Joerg Schilling
Reviewed by: jilles (previous version), pho
Tested by: pho
Sponsored by: The FreeBSD Foundation
Add support for the <sys/mman.h> functions by wrapping around our own
implementations. There are no kern_*() variants of these system calls,
but we also don't need them in this case. It is sufficient to just call
into the sys_*() functions.
Differential Revision: https://reviews.freebsd.org/D3033
Reviewed by: brooks
Summary:
For CloudABI we need to put two things on the stack of new processes:
the argument data (a binary blob; not strings) and a startup data
structure. The startup data structure contains interesting things such
as a pointer to the ELF program header, the thread ID of the initial
thread, a stack smashing protection canary, and a pointer to the
argument data.
Fetching system call arguments and setting the return value is similar
to FreeBSD. The only differences are that system call 0 does not exist
and that we call into cloudabi_convert_errno() to convert the error
code. We also need this function in a couple of other places, so we'd
better reuse it here.
Reviewers: dchagin, kib
Reviewed By: kib
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3098
Summary:
In a runtime that is purely based on capability-based security, there is
a strong emphasis on how programs start their execution. We need to make
sure that we execute an new program with an exact set of file
descriptors, ensuring that credentials are not leaked into the process
accidentally.
Providing the right file descriptors is just half the problem. There
also needs to be a framework in place that gives meaning to these file
descriptors. How does a CloudABI mail server know which of the file
descriptors corresponds to the socket that receives incoming emails?
Furthermore, how will this mail server acquire its configuration
parameters, as it cannot open a configuration file from a global path on
disk?
CloudABI solves this problem by replacing traditional string command
line arguments by tree-like data structure consisting of scalars,
sequences and mappings (similar to YAML/JSON). In this structure, file
descriptors are treated as a first-class citizen. When calling exec(),
file descriptors are passed on to the new executable if and only if they
are referenced from this tree structure. See the cloudabi-run(1) man
page for more details and examples (sysutils/cloudabi-utils).
Fortunately, the kernel does not need to care about this tree structure
at all. The C library is responsible for serializing and deserializing,
but also for extracting the list of referenced file descriptors. The
system call only receives a copy of the serialized data and a layout of
what the new file descriptor table should look like:
int proc_exec(int execfd, const void *data, size_t datalen, const int *fds,
size_t fdslen);
This change introduces a set of fd*_remapped() functions:
- fdcopy_remapped() pulls a copy of a file descriptor table, remapping
all of the file descriptors according to the provided mapping table.
- fdinstall_remapped() replaces the file descriptor table of the process
by the copy created by fdcopy_remapped().
- fdescfree_remapped() frees the table in case we aborted before
fdinstall_remapped().
We then add a function exec_copyin_data_fds() that builds on top these
functions. It copies in the data and constructs a new remapped file
descriptor. This is used by cloudabi_sys_proc_exec().
Test Plan:
cloudabi-run(1) is capable of spawning processes successfully, providing
it data and file descriptors. procstat -f seems to confirm all is good.
Regular FreeBSD processes also work properly.
Reviewers: kib, mjg
Reviewed By: mjg
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3079
We can map these system calls directly to the FreeBSD counterparts. The
other filesystem related system calls will be sent out for review
separately, as they are a bit more complex to get right.
The random_get() system call works similar to getentropy()/getrandom()
on OpenBSD/Linux. It fills a buffer with random data.
This change introduces a new function, read_random_uio(), that is used
to implement read() on the random devices. We can call into this
function from within the CloudABI compatibility layer.
Approved by: secteam
Reviewed by: jmg, markm, wblock
Obtained from: https://github.com/NuxiNL/freebsd
Differential Revision: https://reviews.freebsd.org/D3053
The first system call is used to set the user TLS address. Right now
this system call is invoked by the C library for both the initial thread
and additional threads unconditionally, but in the future we'll only
call this if the architecture does not support this. On recent x86-64
CPUs we could use the WRFSBASE instruction.
This system call was erroneously placed in sys/compat/cloudabi64, even
though it does not depend on any pointer size dependent datastructure.
Move it to the right place.
Obtained from: https://github.com/NuxiNL/freebsd
Add a routine similar to copyinuio() and freebsd32_copyinuio() that
copies in CloudABI's struct iovecs. These are then translated into
FreeBSD format and placed in a 'struct uio', so we can call into the
kern_*() functions.
Obtained from: https://github.com/NuxiNL/freebsd
Summary:
As discussed with kib@ in response to r285404, don't call into
kern_sigaction() within proc_raise() to reset the signal to the default
action before delivery. We'd better do that during image execution.
Change the code to simply use pksignal(), so we don't waste cycles on
functions like pfind() to look up the currently running process itself.
Test Plan:
This change has also been pushed into the cloudabi branch on GitHub. The
raise() tests still seem to pass.
Reviewers: kib
Reviewed By: kib
Subscribers: imp
Differential Revision: https://reviews.freebsd.org/D3076
CloudABI does not provide an explicit kill() system call, for the reason
that there is no access to the global process namespace. Instead, it
offers a raise() system call that can at least be used to terminate the
process abnormally.
CloudABI does not support installing signal handlers. CloudABI's raise()
system call should behave as if the default policy is set up. Call into
kern_sigaction(SIG_DFL) before calling sys_kill() to force this.
Obtained from: https://github.com/NuxiNL/freebsd
Previously several places were doing it on its own, partially
incorrectly (e.g. without the filedesc locked) or even actively harmful
by populating jdir or assigning rootvnode without vrefing it.
Reviewed by: kib
All of the CloudABI system calls that operate on file descriptors of an
arbitrary type are prefixed with fd_. This change adds wrappers for
most of these system calls around their FreeBSD equivalents.
The dup2() system call present on CloudABI deviates from POSIX, in the
sense that it can only be used to replace existing file descriptor. It
cannot be used to create new ones. The reason for this is that this is
inherently thread-unsafe. Furthermore, there is no need on CloudABI to
use fixed file descriptor numbers. File descriptors 0, 1 and 2 have no
special meaning.
This change exposes the kern_dup() through <sys/syscallsubr.h> and puts
the FDDUP_* flags in <sys/filedesc.h>. It then adds a new flag,
FDDUP_MUSTREPLACE to force that file descriptors are replaced -- not
allocated.
Differential Revision: https://reviews.freebsd.org/D3035
Reviewed by: mjg
CloudABI is a pure capability-based runtime environment for UNIX. It
works similar to Capsicum, except that processes already run in
capabilities mode on startup. All functionality that conflicts with this
model has been omitted, making it a compact binary interface that can be
supported by other operating systems without too much effort.
CloudABI is 'secure by default'; the idea is that it should be safe to
run arbitrary third-party binaries without requiring any explicit
hardware virtualization (Bhyve) or namespace virtualization (Jails). The
rights of an application are purely determined by the set of file
descriptors that you grant it on startup.
The datatypes and constants used by CloudABI's C library (cloudlibc) are
defined in separate files called syscalldefs_mi.h (pointer size
independent) and syscalldefs_md.h (pointer size dependent). We import
these files in sys/contrib/cloudabi and wrap around them in
cloudabi*_syscalldefs.h.
We then add stubs for all of the system calls in sys/compat/cloudabi or
sys/compat/cloudabi64, depending on whether the system call depends on
the pointer size. We only have nine system calls that depend on the
pointer size. If we ever want to support 32-bit binaries, we can simply
add sys/compat/cloudabi32 and implement these nine system calls again.
The next step is to send in code reviews for the individual system call
implementations, but also add a sysentvec, to allow CloudABI executabled
to be started through execve().
More information about CloudABI:
- GitHub: https://github.com/NuxiNL/cloudlibc
- Talk at BSDCan: https://www.youtube.com/watch?v=SVdF84x1EdA
Differential Revision: https://reviews.freebsd.org/D2848
Reviewed by: emaste, brooks
Obtained from: https://github.com/NuxiNL/freebsd
Use the same scheme implemented to manage credentials.
Code needing to look at process's credentials (as opposed to thred's) is
provided with *_proc variants of relevant functions.
Places which possibly had to take the proc lock anyway still use the proc
pointer to access limits.
When providing memory map information to userland, populate the vnode pointer
for tmpfs files. Set the memory mapping to appear as a vnode type, to match
FreeBSD 9 behavior.
This fixes the use of tmpfs files with the dtrace pid provider,
procstat -v, procfs, linprocfs, pmc (pmcstat), and ptrace (PT_VM_ENTRY).
Submitted by: Eric Badger <eric@badgerio.us> (initial revision)
Obtained from: Dell Inc.
PR: 198431
MFC after: 2 weeks
Reviewed by: jhb
Approved by: kib (mentor)
writes the remaining time into the structure pointed to by rmtp
unless rmtp is NULL. The value of *rmtp can then be used to call
nanosleep() again and complete the specified pause if the previous
call was interrupted.
Note. clock_nanosleep() with an absolute time value does not write
the remaining time.
While here fix whitespaces and typo in SDT_PROBE.
implemented via ioctl interface. First of all return ENOTSUP for this
operation as a cp fallback to usual method in that case. Secondly, do
not print out the message about unimplemented operation.
1. Linux sigset always 64 bit on all platforms. In order to move Linux
sigset code to the linux_common module define it as 64 bit int. Move
Linux sigset manipulation routines to the MI path.
2. Move Linux signal number definitions to the MI path. In general, they
are the same on all platforms except for a few signals.
3. Map Linux RT signals to the FreeBSD RT signals and hide signal conversion
tables to avoid conversion errors.
4. Emulate Linux SIGPWR signal via FreeBSD SIGRTMIN signal which is outside
of allowed on Linux signal numbers.
PR: 197216
argument is not a null pointer, and the ss_flags member pointed to by ss
contains flags other than SS_DISABLE. However, in fact, Linux also
allows SS_ONSTACK flag which is simply ignored.
For buggy apps (at least mono) ignore other than SS_DISABLE
flags as a Linux do.
While here move MI part of sigaltstack code to the appropriate place.
Reported by: abi at abinet dot ru
"highly experimental" remove /dev/shm magic commited
in r218497 and convert tmpfs type to an expected magic number.
Differential Revision: https://reviews.freebsd.org/D1497
Reviewed by: emaste, trasz
as it already zeroed by malloc with M_ZERO flag
and move zeroing to the proper place in exec path.
Differential Revision: https://reviews.freebsd.org/D1462
Reviewed by: trasz
