ae9d60ce4e
Add a bit of code that tries to get the right parameter order in place for some of the better known architectures, and skips restrict_namespaces for other archs. This also bypasses the test on archs where we don't know the right order. In this case I didn't bother with testing the case where no filter is applied, since that is hopefully just an issue for now, as there's nothing stopping us from supporting more archs, we just need to know which order is right. Fixes: #5241
82 lines
3.2 KiB
C
82 lines
3.2 KiB
C
#pragma once
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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Copyright 2016 Michael Karcher
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <sched.h>
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#include <sys/syscall.h>
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#include "log.h"
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#include "macro.h"
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/**
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* raw_clone() - uses clone to create a new process with clone flags
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* @flags: Flags to pass to the clone system call
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*
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* Uses the clone system call to create a new process with the cloning
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* flags and termination signal passed in the flags parameter. Opposed
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* to glibc's clone funtion, using this function does not set up a
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* separate stack for the child, but relies on copy-on-write semantics
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* on the one stack at a common virtual address, just as fork does.
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*
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* To obtain copy-on-write semantics, flags must not contain CLONE_VM,
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* and thus CLONE_THREAD and CLONE_SIGHAND (which require CLONE_VM) are
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* not usabale.
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* Additionally, as this function does not pass the ptid, newtls and ctid
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* parameters to the kernel, flags must not contain CLONE_PARENT_SETTID,
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* CLONE_CHILD_SETTID, CLONE_CHILD_CLEARTID or CLONE_SETTLS.
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*
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* Returns: 0 in the child process and the child process id in the parent.
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*/
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static inline int raw_clone(unsigned long flags) {
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assert((flags & (CLONE_VM|CLONE_PARENT_SETTID|CLONE_CHILD_SETTID|
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CLONE_CHILD_CLEARTID|CLONE_SETTLS)) == 0);
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#if defined(__s390x__) || defined(__s390__) || defined(__CRIS__)
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/* On s390/s390x and cris the order of the first and second arguments
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* of the raw clone() system call is reversed. */
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return (int) syscall(__NR_clone, NULL, flags);
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#elif defined(__sparc__) && defined(__arch64__)
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{
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/**
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* sparc64 always returns the other process id in %o0, and
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* a boolean flag whether this is the child or the parent in
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* %o1. Inline assembly is needed to get the flag returned
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* in %o1.
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*/
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int in_child;
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int child_pid;
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asm volatile("mov %2, %%g1\n\t"
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"mov %3, %%o0\n\t"
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"mov 0 , %%o1\n\t"
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"t 0x6d\n\t"
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"mov %%o1, %0\n\t"
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"mov %%o0, %1" :
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"=r"(in_child), "=r"(child_pid) :
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"i"(__NR_clone), "r"(flags) :
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"%o1", "%o0", "%g1" );
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if (in_child)
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return 0;
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else
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return child_pid;
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}
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#else
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return (int) syscall(__NR_clone, flags, NULL);
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#endif
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}
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