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Arthur Gautier
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Initial commit
Signed-off-by: Arthur Gautier <[email protected]>
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‎.clang-format

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AlwaysBreakAfterDefinitionReturnType: true
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BasedOnStyle: LLVM
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IndentWidth: 8
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UseTab: Always
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BreakBeforeBraces: Linux
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AllowShortIfStatementsOnASingleLine: false
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IndentCaseLabels: false

‎.gitignore

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/common.o
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/platform/linux/linux.o
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/platform/linux/linux_ptrace.o
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/reallocarray.o
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/setns
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/setns.o

‎Makefile

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CFLAGS += -D_GNU_SOURCE
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CFLAGS += -Wall
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CFLAGS += -Wextra
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CFLAGS += -Werror
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CFLAGS += -Wmissing-declarations
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OBJS=setns.o
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OBJS+=common.o
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OBJS+=reallocarray.o
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UNAME_S := $(shell uname -s)
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ifeq ($(UNAME_S),Linux)
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OBJS+=platform/linux/linux_ptrace.o
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OBJS+=platform/linux/linux.o
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endif
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.PHONY: all
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all: setns
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setns: $(OBJS)
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common.o: common.h
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setns.o: ptrace.h common.h platform/platform.h $(wildcard platform/*/arch/*.h)
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ptrace.o: ptrace.h platform/platform.h $(wildcard platform/*/arch/*.h)
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.PHONY: clean
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clean:
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rm -f setns $(OBJS)
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.PHONY: format
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format:
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clang-format-3.7 -i *.h *.c $(shell find platform -type f -name '*.c' -o -name '*.h')

‎common.c

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#include <stdio.h>
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#include <stdlib.h>
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#include "platform/platform.h"
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#include "common.h"
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#include "reallocarray.h"
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static void
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_debug(const char *pfx, const char *msg, va_list ap)
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{
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if (pfx)
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fprintf(stderr, "%s", pfx);
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vfprintf(stderr, msg, ap);
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fprintf(stderr, "\n");
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}
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void
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die(const char *msg, ...)
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{
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va_list ap;
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va_start(ap, msg);
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_debug("[!] ", msg, ap);
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va_end(ap);
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exit(1);
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}
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void
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debug(const char *msg, ...)
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{
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va_list ap;
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va_start(ap, msg);
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_debug("[+] ", msg, ap);
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va_end(ap);
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}
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void
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error(const char *msg, ...)
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{
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va_list ap;
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va_start(ap, msg);
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_debug("[-] ", msg, ap);
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va_end(ap);
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}
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int
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fd_array_push(struct fd_array *fda, int fd)
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{
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int *tmp;
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if (fda->n == fda->allocated) {
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fda->allocated = fda->allocated ? 2 * fda->allocated : 2;
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tmp = xreallocarray(fda->fds, fda->allocated, sizeof *tmp);
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if (tmp == NULL) {
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free(fda->fds);
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fda->fds = NULL;
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fda->allocated = 0;
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return -1;
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}
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fda->fds = tmp;
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}
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fda->fds[fda->n++] = fd;
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return 0;
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}

‎common.h

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#include <stdarg.h>
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#define assert_nonzero(expr) \
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({ \
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typeof(expr) __val = expr; \
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if (__val == 0) \
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die("Unexpected: %s == 0!\n", #expr); \
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__val; \
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})
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#define __printf __attribute__((format(printf, 1, 2)))
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void __printf die(const char *msg, ...) __attribute__((noreturn));
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void __printf debug(const char *msg, ...);
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void __printf error(const char *msg, ...);

‎platform/linux/arch/amd64.h

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/*
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* Copyright (C) 2011 by Nelson Elhage
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17+
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "x86_common.h"
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#define ARCH_HAVE_MULTIPLE_PERSONALITIES
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static struct ptrace_personality arch_personality[2] = {
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{
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offsetof(struct user, regs.rax), offsetof(struct user, regs.rdi),
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offsetof(struct user, regs.rsi), offsetof(struct user, regs.rdx),
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offsetof(struct user, regs.r10), offsetof(struct user, regs.r8),
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offsetof(struct user, regs.r9), offsetof(struct user, regs.rip),
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},
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{
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offsetof(struct user, regs.rax), offsetof(struct user, regs.rbx),
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offsetof(struct user, regs.rcx), offsetof(struct user, regs.rdx),
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offsetof(struct user, regs.rsi), offsetof(struct user, regs.rdi),
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offsetof(struct user, regs.rbp), offsetof(struct user, regs.rip),
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},
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};
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struct x86_personality x86_personality[2] = {
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{
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offsetof(struct user, regs.orig_rax), offsetof(struct user, regs.rax),
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},
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{
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offsetof(struct user, regs.orig_rax), offsetof(struct user, regs.rax),
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},
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};
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struct syscall_numbers arch_syscall_numbers[2] = {
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#include "default-syscalls.h"
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{
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/*
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* These don't seem to be available in any convenient header. We could
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* include unistd_32.h, but those definitions would conflict with the
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* standard ones. So, let's just hardcode the values for now. Probably
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* we should generate this from unistd_32.h during the build process or
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* soemthing.
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*/
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.nr_mmap = 90,
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.nr_mmap2 = 192,
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.nr_munmap = 91,
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.nr_getsid = 147,
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.nr_setsid = 66,
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.nr_setpgid = 57,
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.nr_fork = 2,
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.nr_wait4 = 114,
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.nr_signal = 48,
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.nr_rt_sigaction = 174,
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.nr_open = 5,
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.nr_close = 6,
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.nr_ioctl = 54,
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.nr_dup2 = 63,
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.nr_socketcall = 102,
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.nr_setns = 346,
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}};
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static int
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arch_get_personality(struct ptrace_child *child)
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{
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unsigned long cs;
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cs = ptrace_command(child, PTRACE_PEEKUSER,
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offsetof(struct user, regs.cs));
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if (child->error)
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return -1;
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if (cs == 0x23)
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child->personality = 1;
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return 0;
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}

‎platform/linux/arch/default-syscalls.h

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#define SC(name) .nr_##name = __NR_##name
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{
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#ifdef __NR_mmap
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SC(mmap),
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#else
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.nr_mmap = -1,
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#endif
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#ifdef __NR_mmap2
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SC(mmap2),
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#else
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.nr_mmap2 = -1,
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#endif
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SC(munmap),
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SC(getsid),
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SC(setsid),
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SC(setpgid),
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SC(fork),
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SC(wait4),
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#ifdef __NR_signal
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SC(signal),
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#else
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.nr_signal = -1,
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#endif
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SC(rt_sigaction),
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SC(open),
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SC(close),
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SC(ioctl),
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SC(dup2),
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#ifdef __NR_socketcall
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SC(socketcall),
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#else
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SC(socket),
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SC(connect),
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SC(sendmsg),
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#endif
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SC(setns),
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}
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,
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#undef SC

‎platform/linux/arch/x86_common.h

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/*
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* Copyright (C) 2011 by Nelson Elhage
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
5+
* of this software and associated documentation files (the "Software"), to deal
6+
* in the Software without restriction, including without limitation the rights
7+
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8+
* copies of the Software, and to permit persons to whom the Software is
9+
* furnished to do so, subject to the following conditions:
10+
*
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* The above copyright notice and this permission notice shall be included in
12+
* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15+
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16+
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17+
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18+
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19+
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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struct x86_personality {
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size_t orig_ax;
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size_t ax;
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};
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struct x86_personality x86_personality[];
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static inline struct x86_personality *
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x86_pers(struct ptrace_child *child)
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{
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return &x86_personality[child->personality];
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}
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static inline void
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arch_fixup_regs(struct ptrace_child *child)
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{
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struct x86_personality *x86pers = x86_pers(child);
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struct ptrace_personality *pers = personality(child);
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struct user *user = &child->user;
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#define ptr(user, off) ((unsigned long *)((void *)(user) + (off)))
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*ptr(user, pers->reg_ip) -= 2;
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*ptr(user, x86pers->ax) = *ptr(user, x86pers->orig_ax);
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}
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static inline int
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arch_set_syscall(struct ptrace_child *child, unsigned long sysno)
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{
50+
return ptrace_command(child, PTRACE_POKEUSER, x86_pers(child)->orig_ax,
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sysno);
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}
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static inline int
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arch_save_syscall(struct ptrace_child *child)
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{
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child->saved_syscall = *ptr(&child->user, x86_pers(child)->orig_ax);
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return 0;
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}
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static inline int
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arch_restore_syscall(__attribute__((unused)) struct ptrace_child *child)
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{
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return 0;
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}
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#undef ptr

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