Track supplementary GIDs per task group, wire setgroups/getgroups
syscalls when CONFIG_SCHED_NGROUPS > 0, and honor them in DAC checks
via nxsched_has_gid(). When NGROUPS is 0, libc provides getgroups/
setgroups stubs. initgroups() fails instead of silently truncating
when membership exceeds CONFIG_SCHED_NGROUPS.
Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
NuttX implemented fork() and vfork() as the same function. Both were libc
wrappers around a single up_fork() syscall; vfork() differed only by a
trailing waitpid(). Underneath, the child joined the parent's address
environment -- the same addrenv_join() that pthread_create() uses -- and got
a private copy of the stack. So the child shared .data, .bss and the heap
with its parent and ran concurrently with it.
That is not fork(). It is vfork()-with-a-private-stack under fork()'s name,
and the history says so: today's fork() is NuttX's old vfork(), renamed in
c33d1c9c97 (2023) without any change of behaviour. The failure was silent --
a program written against POSIX fork() compiled, ran, and had its child's
writes land in the parent's variables.
Separate them into two primitives, chosen by which function the caller
called rather than by what the hardware happens to be:
fork() child gets its own copy of the parent's memory at the same
virtual addresses; runs concurrently. Only where an address
environment can be duplicated -- elsewhere it is not declared at
all, so calling it is a build error naming the function.
vfork() child shares the parent's memory; parent suspended until the
child _exit()s or exec()s. Implementable everywhere.
Below libc there is still one syscall. up_fork() gains a bool saying which
primitive the caller used, since the per-architecture register snapshot is
the same for both, and passes it to nxtask_setup_fork(), which is the single
place the memory semantics are decided. The argument arrives in the first
argument register and is never touched: each architecture's snapshot takes
some other call-clobbered register for its scratch, so the flag is simply
still there when the C worker is called.
The vfork() parent suspension moves out of libc into nxtask_start_fork(),
released from nxsched_release_tcb() by nxtask_resume_vfork(). Two things
follow: the parent is resumed at exec(), since exec_swap() has already handed
the child's pid to the loaded program by the time the vfork stub exits, and
vfork() no longer depends on CONFIG_SCHED_WAITPID.
Releasing there requires one fix in nxtask_exit(). It raises rtcb->lockcount
directly rather than through sched_lock() while it tears the TCB down, so the
nxsem_post() that wakes the vfork() parent leaves it queued where a blocked
task collects while pre-emption is off -- g_pendingtasks, or g_readytorun on
SMP -- and the matching raw lockcount-- does not publish it the way
sched_unlock() would, leaving the parent stranded with nothing to move it on.
The fix mirrors sched_unlock() for each case: nxsched_merge_pending(), or
nxsched_deliver_task() under CONFIG_SMP. Both are no-ops while pre-emption is
still disabled, and up_exit() re-reads this_task() afterwards, so a change of
the ready-to-run head is honoured. Without it vfork() deadlocks wherever no
other task happens to call sched_unlock() afterwards -- rv-virt:nsh64 and
rv-virt:pnsh64, where NSH is blocked in waitpid() holding the lock, and
qemu-armv8a:citest_smp, which hangs the moment the vfork() test runs.
fork() is built on a new addrenv_fork(), backed by an up_addrenv_fork() hook
that duplicates an address environment into freshly allocated pages mapped at
the same virtual addresses -- unlike up_addrenv_clone(), which copies only
the representation and leaves both pointing at the same page tables. The
child then adopts the parent's stack geometry rather than being given a
relocated copy: a pointer to a stack local taken before fork() must name the
same object in the child that it named in the parent, and the parent's stack
is already in the duplicate, with its contents, at the parent's address.
No architecture implements up_addrenv_fork() yet, so this commit leaves
fork() unavailable everywhere. That is the intended state. It withdraws
fork() from ARCH_ARM, flat ARCH_ARM64, ARCH_RISCV, ARCH_SIM and ARCH_X86_64,
where until now it named the sharing primitive; per-architecture patches
restore it, with POSIX semantics, as up_addrenv_fork() lands. In the
meantime the sharing primitive is still there under the name that describes
it: vfork() for a child that runs a program, pthread_create() for a second
flow of control that shares memory, posix_spawn() for both at once.
Kconfig: ARCH_HAVE_VFORK inherits ARCH_HAVE_FORK's select lines, conditions
included, so no configuration gains machinery; ARCH_HAVE_FORK is redefined to
mean "can provide POSIX fork() semantics" and now depends on ARCH_ADDRENV.
There is one deliberate departure from "verbatim". ARCH_ARM selected the
fork family unconditionally, BUILD_KERNEL included, and that has never
worked: on a kernel build the architecture's fork entry point sees the
kernel's return address and stack pointer rather than the caller's, so the
child resumes at a kernel address. On qemu-armv7a:knsh master faults in
ostest's fork case with "Child did not run" and then a data abort; without
the condition this change faults the same way through vfork(). ARCH_ARM64
and ARCH_X86_64 already carried "if !BUILD_KERNEL" for exactly this reason --
ARM was the outlier. Conditioning it turns a runtime fault into an honest
absence, which is the whole point of the change; arch/arm takes the condition
off again in the patch that adds its saved-syscall-frame path. Only the
MMU-capable ARM ports are affected, since Cortex-M cannot build BUILD_KERNEL
at all.
Also fixes two latent syntax errors found on the way: a missing comma in
riscv_fork.c and mips_fork.c, both in *_FRAMEPOINTER && !SAVE_GP branches
that are never compiled today.
BREAKING CHANGE: fork() is withdrawn from every architecture. It is no
longer declared in unistd.h, so code that calls it fails to build with an error
naming the function, and the sharing behaviour it used to have is gone rather
than renamed. CONFIG_ARCH_HAVE_FORK no longer means "fork() exists"; it means
"this configuration can provide POSIX fork() semantics", and no architecture
selects it yet.
Quick fix, chosen by why the call was made:
to run a program vfork() + exec*(), or better posix_spawn()
a second flow of control that pthread_create()
shares the caller's memory
a genuinely independent copy keep fork(), and wait for the per-arch patch
of the process that implements up_addrenv_fork() and selects
CONFIG_ARCH_HAVE_FORK
Out-of-tree code that tests CONFIG_ARCH_HAVE_FORK to decide whether a
fork-then-exec path is available wants CONFIG_ARCH_HAVE_VFORK instead, which is
selected in exactly the places CONFIG_ARCH_HAVE_FORK used to be. The full
migration guide is Documentation/guides/fork_vfork_migration.rst.
Assisted-by: Claude Code:claude-opus-5
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
Implement POSIX real/effective/saved credential getters and paired
setters in the task group layer, with libc stubs and syscalls.
Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
Add getgroups() to the C library. NuttX has no supplementary group
IDs, so it reports a single group, the effective group ID, and follows
POSIX for the gidsetsize == 0 and short-buffer (EINVAL) cases.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
NuttX has no real session/process-group abstraction, so the TTY layer
collapses the foreground process group onto the single dev->pid field
(pgrp == pid, one member per group). Extend the controlling-terminal
support so portable software (e.g. dropbear, socat) that relies on
job-control primitives works without losing the existing NuttX-specific
behaviour.
Driver (serial.c, pty.c):
- TIOCSCTTY now accepts a flag: arg > 0 keeps the historical "target
PID in arg" semantics (NSH registers the foreground command it just
spawned), while arg == 0 selects the calling task via
nxsched_getpid(), matching the POSIX flag convention used by
dropbear/socat/apue. This preserves all existing callers and makes
the previously-dead arg==0 path deliver SIGINT correctly.
- Add TIOCGPGRP/TIOCGSID (return dev->pid) and TIOCSPGRP (set it).
- pty.c gains the same handlers against pd_pid and includes
nuttx/sched.h for nxsched_getpid().
ioctl numbers (tioctl.h): TIOCGPGRP/TIOCSPGRP/TIOCGSID at 0x37-0x39.
libc wrappers:
- termios: tcgetpgrp(), tcsetpgrp(), tcgetsid() over the new ioctls.
- unistd: setsid()/getsid()/setpgid() stubs consistent with the
existing getpgrp()/getpgid() single-session model (sid == pgid ==
pid; setpgid only succeeds for pgid == pid).
Declare the new prototypes in unistd.h (tcgetsid was already in
termios.h) and register all sources in the Make.defs/CMakeLists.
Group-broadcast signalling (kill(-pgrp)) remains unsupported, so
tty signals still target the single dev->pid; a real session/process
group model is left as a follow-up.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Add declarations for dpopen() and dpclose() to unistd.h. These are
the descriptor-based counterparts of popen()/pclose() declared in
stdio.h. The implementation lives in apps/system/popen/dpopen.c.
Signed-off-by: cuiziwei <cuiziwei@xiaomi.com>
Replace the pipe() macro definition with a proper function implementation
to improve POSIX compliance and debugging capabilities. The new pipe()
function serves as a wrapper around pipe2() with flags set to 0.
Changes include:
- Convert pipe() from macro to function declaration in unistd.h
- Add lib_pipe.c implementation file with proper function documentation
- Update build system files (CMakeLists.txt and Make.defs) to include
the new source file when CONFIG_PIPES is enabled
- Add pipe() entry to libc.csv for symbol tracking
This change allows for better debugging, proper symbol resolution,
and follows NuttX coding standards for library function implementations.
Signed-off-by: Huang Qi <huangqi3@xiaomi.com>
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
1. the getpgid function can help to pass the
ltp/open_posix_testsuite/killpg related testcases
2. NuttX do not support process group, so we use the process id as
process group id
3. the implementation are referred to: https://pubs.opengroup.org/onlinepubs/9699919799/functions/getpgid.html
Signed-off-by: guoshichao <guoshichao@xiaomi.com>
1. as we can use fork to implement vfork, so we rename the vfork to
fork, and use the fork method as the base to implement vfork method
2. create the vfork function as a libc function based on fork
function
Signed-off-by: guoshichao <guoshichao@xiaomi.com>
1. the getpgrp function can help to pass the ltp/open_posix_teststuite/killpg related testcases
2. Nuttx do not support process group, so we use getpid to implement this
3. the implementation are referred to: https://pubs.opengroup.org/onlinepubs/9699919799/functions/getpgrp.html
Signed-off-by: guoshichao <guoshichao@xiaomi.com>
This function will use gcc's function
__builtin_dynamic_object_size and __builtin_object_size
Its function is to obtain the size of the object through compilation,
so as to judge whether there are out-of-bounds operations in commonly used functions.
It should be noted that the option -O2 and above is required to enable this function
Signed-off-by: anjiahao <1090959677@qq.com>
commit e1c306f2dd added sethostname using
strncpy. This replaces it with strlcpy and uses sizeof() instead of
re-calculating the buffer size.
Rename size argument for get/sethostname to match the implementation
and implement all status related change function. the individual
file system change will provide in other upcoming patchset.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I8fde9db8eba9586e9c8da078b67e020c26623cf4
Note: this patch can get file path from root pseudo file handle,
but a general infrastructure is setup for other file system too.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I86cd79ebb741f2f43fdd398bb7498c40687d949b
getopt() in the FLAT build environment is not thread safe. This is because global variables that are process-specific in Unix are truly global in the FLAT build. Moving the getopt() variables into TLS resolves this issue.
No side-effects are expected other than to getopt()
Tested with sim:nsh
