clone.c

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/*
 * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <signal.h>
#include <sched.h>
#include <asm/unistd.h>
#include <sys/time.h>
#include <as-layout.h>
#include <ptrace_user.h>
#include <stub-data.h>
#include <sysdep/stub.h>

/*
 * This is in a separate file because it needs to be compiled with any
 * extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
 *
 * Use UM_KERN_PAGE_SIZE instead of PAGE_SIZE because that calls getpagesize
 * on some systems.
 */

void __attribute__ ((__section__ (".__syscall_stub")))
stub_clone_handler(void)
{
    struct stub_data *data = (struct stub_data *) STUB_DATA;
    long err;

    err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
                STUB_DATA + UM_KERN_PAGE_SIZE / 2 - sizeof(void *));
    if (err != 0)
        goto out;

    err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
    if (err)
        goto out;

    err = stub_syscall3(__NR_setitimer, ITIMER_VIRTUAL,
                (long) &data->timer, 0);
    if (err)
        goto out;

    remap_stack(data->fd, data->offset);
    goto done;

 out:
    /*
     * save current result.
     * Parent: pid;
     * child: retcode of mmap already saved and it jumps around this
     * assignment
     */
    data->err = err;
 done:
    trap_myself();
}