/*
 * Copyright (c) 2006 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/cons.h>
#include <sys/random.h>
#include <sys/vkernel.h>
#include <sys/tls.h>
#include <sys/reboot.h>
#include <sys/proc.h>
#include <sys/msgbuf.h>
#include <sys/vmspace.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/un.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <sys/mplock2.h>
#include <sys/wait.h>

#include <machine/cpu.h>
#include <machine/globaldata.h>
#include <machine/tls.h>
#include <machine/md_var.h>
#include <machine/vmparam.h>
#include <cpu/specialreg.h>

#include <net/if.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#include <net/bridge/if_bridgevar.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if_var.h>

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdbool.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <err.h>
#include <errno.h>
#include <assert.h>
#include <sysexits.h>
#include <pthread.h>

#define EX_VKERNEL_REBOOT       32

vm_phystable_t phys_avail[16];
vm_paddr_t Maxmem;
vm_paddr_t Maxmem_bytes;
long physmem;
int MemImageFd = -1;
struct vkdisk_info DiskInfo[VKDISK_MAX];
int DiskNum;
struct vknetif_info NetifInfo[VKNETIF_MAX];
int NetifNum;
char *pid_file;
vm_offset_t KvaStart;
vm_offset_t KvaEnd;
vm_offset_t KvaSize;
vm_offset_t virtual_start;
vm_offset_t virtual_end;
vm_offset_t virtual2_start;
vm_offset_t virtual2_end;
vm_offset_t kernel_vm_end;
vm_offset_t crashdumpmap;
vm_offset_t clean_sva;
vm_offset_t clean_eva;
struct msgbuf *msgbufp;
caddr_t ptvmmap;
vpte_t  *KernelPTD;
vpte_t  *KernelPTA;     /* Warning: Offset for direct VA translation */
void *dmap_min_address;
void *vkernel_stack;
u_int cpu_feature;      /* XXX */
u_int cpu_feature2;     /* XXX */
int tsc_present;
int tsc_invariant;
int tsc_mpsync;
int optcpus;            /* number of cpus - see mp_start() */
int cpu_bits;
int lwp_cpu_lock;       /* if/how to lock virtual CPUs to real CPUs */
int real_ncpus;         /* number of real CPUs */
int next_cpu;           /* next real CPU to lock a virtual CPU to */
int vkernel_b_arg;      /* no of logical CPU bits - only SMP */
int vkernel_B_arg;      /* no of core bits - only SMP */
int use_precise_timer = 0;      /* use a precise timer (more expensive) */
struct privatespace *CPU_prvspace;

tsc_uclock_t tsc_frequency;
tsc_uclock_t tsc_oneus_approx;

extern uint64_t KPML4phys;      /* phys addr of kernel level 4 */

static struct trapframe proc0_tf;
static void *proc0paddr;

static void init_sys_memory(char *imageFile);
static void init_kern_memory(void);
static void init_globaldata(void);
static void init_vkernel(void);
static void init_disk(char **diskExp, int *diskFlags, int diskFileNum, enum vkdisk_type type);
static void init_netif(char *netifExp[], int netifFileNum);
static void writepid(void);
static void cleanpid(void);
static int unix_connect(const char *path);
static void usage_err(const char *ctl, ...) __printflike(1, 2);
static void usage_help(_Bool);
static void init_locks(void);
static void handle_term(int);

pid_t childpid;

static int save_ac;
static int prezeromem;
static char **save_av;

/*
 * Kernel startup for virtual kernels - standard main()
 */
int
main(int ac, char **av)
{
        char *memImageFile = NULL;
        char *netifFile[VKNETIF_MAX];
        char *diskFile[VKDISK_MAX];
        char *cdFile[VKDISK_MAX];
        char *suffix;
        char *endp;
        char *tmp;
        char *tok;
        int diskFlags[VKDISK_MAX];
        int netifFileNum = 0;
        int diskFileNum = 0;
        int cdFileNum = 0;
        int bootOnDisk = -1;    /* set below to vcd (0) or vkd (1) */
        int c;
        int i;
        int j;
        int n;
        int isq;
        int pos;
        int eflag;
        int real_vkernel_enable;
        int supports_sse;
        size_t vsize;
        size_t msize;
        size_t kenv_size;
        size_t kenv_size2;
        int status;
        struct sigaction sa;

        /*
         * Currently a bad hack but rtld-elf needs LD_SHAREDLIB_BASE to
         * be set to force it to mmap() shared libraries into low memory,
         * so our module loader can link against the related symbols.
         */
        if (getenv("LD_SHAREDLIB_BASE") == NULL) {
                setenv("LD_SHAREDLIB_BASE", "0x10000000", 1);
                execv(av[0], av);
                fprintf(stderr, "Must run %s with full path\n", av[0]);
                exit(1);
        }

        while ((childpid = fork()) != 0) {
                /* Ignore signals */
                bzero(&sa, sizeof(sa));
                sigemptyset(&sa.sa_mask);
                sa.sa_handler = SIG_IGN;
                sigaction(SIGINT, &sa, NULL);
                sigaction(SIGQUIT, &sa, NULL);
                sigaction(SIGHUP, &sa, NULL);

                /*
                 * Forward SIGTERM to the child so that
                 * the shutdown process initiates correctly.
                 */
                sa.sa_handler = handle_term;
                sigaction(SIGTERM, &sa, NULL);

                /*
                 * Wait for child to terminate, exit if
                 * someone stole our child.
                 */
                while (waitpid(childpid, &status, 0) != childpid) {
                        if (errno == ECHILD)
                                exit(1);
                }
                if (WEXITSTATUS(status) != EX_VKERNEL_REBOOT)
                        return 0;
        }

        /*
         * Starting for real
         */
        save_ac = ac;
        save_av = av;
        eflag = 0;
        pos = 0;
        kenv_size = 0;

        /*
         * Process options
         */
        kernel_mem_readonly = 1;
        optcpus = 2;
        cpu_bits = 1;
        vkernel_b_arg = 0;
        vkernel_B_arg = 0;
        lwp_cpu_lock = LCL_NONE;

        real_vkernel_enable = 0;
        vsize = sizeof(real_vkernel_enable);
        sysctlbyname("vm.vkernel_enable", &real_vkernel_enable, &vsize, NULL,0);

        if (real_vkernel_enable == 0) {
                errx(1, "vm.vkernel_enable is 0, must be set "
                        "to 1 to execute a vkernel!");
        }

        real_ncpus = 1;
        vsize = sizeof(real_ncpus);
        sysctlbyname("hw.ncpu", &real_ncpus, &vsize, NULL, 0);

        if (ac < 2)
                usage_help(false);

        while ((c = getopt(ac, av, "c:hsvztTl:m:n:r:R:e:i:p:I:U")) != -1) {
                switch(c) {
                case 'e':
                        /*
                         * name=value:name=value:name=value...
                         * name="value"...
                         *
                         * Allow values to be quoted but note that shells
                         * may remove the quotes, so using this feature
                         * to embed colons may require a backslash.
                         */
                        n = strlen(optarg);
                        isq = 0;

                        if (eflag == 0) {
                                kenv_size = n + 2;
                                kern_envp = malloc(kenv_size);
                                if (kern_envp == NULL)
                                        errx(1, "Couldn't allocate %zd bytes for kern_envp", kenv_size);
                        } else {
                                kenv_size2 = kenv_size + n + 1;
                                pos = kenv_size - 1;
                                if ((tmp = realloc(kern_envp, kenv_size2)) == NULL)
                                        errx(1, "Couldn't reallocate %zd bytes for kern_envp", kenv_size2);
                                kern_envp = tmp;
                                kenv_size = kenv_size2;
                        }

                        for (i = 0, j = pos; i < n; ++i) {
                                if (optarg[i] == '"')
                                        isq ^= 1;
                                else if (optarg[i] == '\'')
                                        isq ^= 2;
                                else if (isq == 0 && optarg[i] == ':')
                                        kern_envp[j++] = 0;
                                else
                                        kern_envp[j++] = optarg[i];
                        }
                        kern_envp[j++] = 0;
                        kern_envp[j++] = 0;
                        eflag++;
                        break;
                case 's':
                        boothowto |= RB_SINGLE;
                        break;
                case 't':
                        use_precise_timer = 1;
                        break;
                case 'v':
                        bootverbose = 1;
                        break;
                case 'i':
                        memImageFile = optarg;
                        break;
                case 'I':
                        if (netifFileNum < VKNETIF_MAX)
                                netifFile[netifFileNum++] = strdup(optarg);
                        break;
                case 'r':
                case 'R':
                        if (bootOnDisk < 0)
                                bootOnDisk = 1;
                        if (diskFileNum + cdFileNum < VKDISK_MAX) {
                                diskFile[diskFileNum] = strdup(optarg);
                                diskFlags[diskFileNum] = (c == 'R');
                                ++diskFileNum;
                        }
                        break;
                case 'c':
                        if (bootOnDisk < 0)
                                bootOnDisk = 0;
                        if (diskFileNum + cdFileNum < VKDISK_MAX)
                                cdFile[cdFileNum++] = strdup(optarg);
                        break;
                case 'm':
                        Maxmem_bytes = strtoull(optarg, &suffix, 0);
                        if (suffix) {
                                switch(*suffix) {
                                case 'g':
                                case 'G':
                                        Maxmem_bytes <<= 30;
                                        break;
                                case 'm':
                                case 'M':
                                        Maxmem_bytes <<= 20;
                                        break;
                                case 'k':
                                case 'K':
                                        Maxmem_bytes <<= 10;
                                        break;
                                default:
                                        Maxmem_bytes = 0;
                                        usage_err("Bad maxmem option");
                                        /* NOT REACHED */
                                        break;
                                }
                        }
                        break;
                case 'l':
                        next_cpu = -1;
                        if (strncmp("map", optarg, 3) == 0) {
                                lwp_cpu_lock = LCL_PER_CPU;
                                if (optarg[3] == ',') {
                                        next_cpu = strtol(optarg+4, &endp, 0);
                                        if (*endp != '\0')
                                                usage_err("Bad target CPU number at '%s'", endp);
                                } else {
                                        next_cpu = 0;
                                }
                                if (next_cpu < 0 || next_cpu > real_ncpus - 1)
                                        usage_err("Bad target CPU, valid range is 0-%d", real_ncpus - 1);
                        } else if (strncmp("any", optarg, 3) == 0) {
                                lwp_cpu_lock = LCL_NONE;
                        } else {
                                lwp_cpu_lock = LCL_SINGLE_CPU;
                                next_cpu = strtol(optarg, &endp, 0);
                                if (*endp != '\0')
                                        usage_err("Bad target CPU number at '%s'", endp);
                                if (next_cpu < 0 || next_cpu > real_ncpus - 1)
                                        usage_err("Bad target CPU, valid range is 0-%d", real_ncpus - 1);
                        }
                        break;
                case 'n':
                        /*
                         * This value is set up by mp_start(), don't just
                         * set ncpus here.
                         */
                        tok = strtok(optarg, ":");
                        optcpus = strtol(tok, NULL, 0);
                        if (optcpus < 1 || optcpus > MAXCPU)
                                usage_err("Bad ncpus, valid range is 1-%d", MAXCPU);
                        cpu_bits = 1;
                        while ((1 << cpu_bits) < optcpus)
                                ++cpu_bits;

                        /*
                         * By default assume simple hyper-threading
                         */
                        vkernel_b_arg = 1;
                        vkernel_B_arg = cpu_bits - vkernel_b_arg;

                        /*
                         * [:lbits[:cbits]] override # of cpu bits
                         * for logical and core extraction, supplying
                         * defaults for any omission.
                         */
                        tok = strtok(NULL, ":");
                        if (tok != NULL) {
                                vkernel_b_arg = strtol(tok, NULL, 0);
                                vkernel_B_arg = cpu_bits - vkernel_b_arg;

                                /* :cbits argument */
                                tok = strtok(NULL, ":");
                                if (tok != NULL) {
                                        vkernel_B_arg = strtol(tok, NULL, 0);
                                }
                        }
                        break;
                case 'p':
                        pid_file = optarg;
                        break;
                case 'U':
                        kernel_mem_readonly = 0;
                        break;
                case 'h':
                        usage_help(true);
                        break;
                case 'z':
                        prezeromem = 1;
                        break;
                default:
                        usage_help(false);
                }
        }

        writepid();
        cpu_disable_intr();
        init_sys_memory(memImageFile);
        init_kern_memory();
        init_globaldata();
        init_vkernel();
        setrealcpu();
        init_kqueue();

        vmm_guest = VMM_GUEST_VKERNEL;

        /*
         * Check TSC
         */
        vsize = sizeof(tsc_present);
        sysctlbyname("hw.tsc_present", &tsc_present, &vsize, NULL, 0);
        vsize = sizeof(tsc_invariant);
        sysctlbyname("hw.tsc_invariant", &tsc_invariant, &vsize, NULL, 0);
        vsize = sizeof(tsc_mpsync);
        sysctlbyname("hw.tsc_mpsync", &tsc_mpsync, &vsize, NULL, 0);
        vsize = sizeof(tsc_frequency);
        sysctlbyname("hw.tsc_frequency", &tsc_frequency, &vsize, NULL, 0);
        if (tsc_present)
                cpu_feature |= CPUID_TSC;
        tsc_oneus_approx = ((tsc_frequency|1) + 999999) / 1000000;

        /*
         * Check SSE and get the host's MXCSR mask.  The mask must be set
         * before init_fpu() because npxprobemask() may not work correctly
         * in userspace context.
         */
        vsize = sizeof(supports_sse);
        supports_sse = 0;
        sysctlbyname("hw.instruction_sse", &supports_sse, &vsize, NULL, 0);
        msize = sizeof(npx_mxcsr_mask);
        sysctlbyname("hw.mxcsr_mask", &npx_mxcsr_mask, &msize, NULL, 0);
        init_fpu(supports_sse);
        if (supports_sse)
                cpu_feature |= CPUID_SSE | CPUID_FXSR;

        /*
         * We boot from the first installed disk.
         */
        if (bootOnDisk == 1) {
                init_disk(diskFile, diskFlags, diskFileNum, VKD_DISK);
                init_disk(cdFile, NULL, cdFileNum, VKD_CD);
        } else {
                init_disk(cdFile, NULL, cdFileNum, VKD_CD);
                init_disk(diskFile, diskFlags, diskFileNum, VKD_DISK);
        }

        init_netif(netifFile, netifFileNum);
        init_exceptions();
        mi_startup();
        /* NOT REACHED */
        exit(EX_SOFTWARE);
}

/* SIGTERM handler */
static
void
handle_term(int sig)
{
        kill(childpid, sig);
}

/*
 * Initialize system memory.  This is the virtual kernel's 'RAM'.
 *
 * We always use an anonymous memory file (created in /tmp or /var/vkernel
 * and immediately unlinked).
 *
 * The -i option is deprecated but still accepted for compatibility.
 */
static
void
init_sys_memory(char *imageFile)
{
        int fd;
        char *tmpfile;

        /*
         * Warn if -i was specified (deprecated)
         */
        if (imageFile != NULL) {
                fprintf(stderr,
                    "WARNING: -i option is deprecated and ignored.\n"
                    "         Memory is now always anonymous (unlinked file).\n");
        }

        /*
         * Require -m to be specified
         */
        if (Maxmem_bytes == 0) {
                errx(1, "System memory size must be specified with -m");
                /* NOT REACHED */
        }

        /*
         * Maxmem must be known at this time
         */
        if (Maxmem_bytes < 64 * 1024 * 1024 || (Maxmem_bytes & SEG_MASK)) {
                errx(1, "Bad maxmem specification: 64MB minimum, "
                       "multiples of %dMB only",
                       SEG_SIZE / 1024 / 1024);
                /* NOT REACHED */
        }

        /*
         * Create an anonymous memory backing file.  We create a temp file
         * and immediately unlink it.  The file descriptor keeps the file
         * alive until the vkernel exits, at which point all pages are
         * properly freed.
         */
        asprintf(&tmpfile, "/var/vkernel/.memimg.%d", (int)getpid());
        fd = open(tmpfile, O_RDWR|O_CREAT|O_EXCL, 0600);
        if (fd < 0)
                err(1, "Unable to create %s", tmpfile);
        unlink(tmpfile);
        free(tmpfile);

        fprintf(stderr, "Using anonymous memory (%llu MB)\n",
                (unsigned long long)Maxmem_bytes / (1024 * 1024));

        /*
         * Size the file.  It will be sparse (no actual disk space used
         * until pages are faulted in).
         */
        if (ftruncate(fd, Maxmem_bytes) < 0) {
                err(1, "Unable to size memory backing file");
                /* NOT REACHED */
        }

        MemImageFd = fd;
        Maxmem = Maxmem_bytes >> PAGE_SHIFT;
        physmem = Maxmem;
}

/*
 * Initialize kernel memory.  This reserves kernel virtual memory by using
 * MAP_VPAGETABLE
 *
 * XXX NOTE!  MAP_VPAGETABLE is being ripped out and will break VKERNELs
 *            for a while, until we get hardware virtualization working.
 */

static
void
init_kern_memory(void)
{
        void *base;
        int i;
        void *firstfree;

        /*
         * Memory map our kernel virtual memory space.  Note that the
         * kernel image itself is not made part of this memory for the
         * moment.
         *
         * The memory map must be segment-aligned so we can properly
         * offset KernelPTD.
         *
         * If the system kernel has a different MAXDSIZ, it might not
         * be possible to map kernel memory in its prefered location.
         * Try a number of different locations.
         */

        base = mmap((void*)KERNEL_KVA_START, KERNEL_KVA_SIZE,
                    PROT_READ|PROT_WRITE|PROT_EXEC,
                    MAP_FILE|MAP_SHARED|MAP_VPAGETABLE|MAP_FIXED|MAP_TRYFIXED,
                    MemImageFd, (off_t)KERNEL_KVA_START);

        if (base == MAP_FAILED) {
                err(1, "Unable to mmap() kernel virtual memory!");
                /* NOT REACHED */
        }
        madvise(base, KERNEL_KVA_SIZE, MADV_NOSYNC);
        KvaStart = (vm_offset_t)base;
        KvaSize = KERNEL_KVA_SIZE;
        KvaEnd = KvaStart + KvaSize;

        /* cannot use kprintf yet */
        printf("KVM mapped at %p-%p\n", (void *)KvaStart, (void *)KvaEnd);

        /* MAP_FILE? */
        dmap_min_address = mmap(0, DMAP_SIZE, PROT_READ|PROT_WRITE,
                                MAP_NOCORE|MAP_NOSYNC|MAP_SHARED,
                                MemImageFd, 0);
        if (dmap_min_address == MAP_FAILED) {
                err(1, "Unable to mmap() kernel DMAP region!");
                /* NOT REACHED */
        }

        /*
         * Prefault the memory.  The vkernel is going to fault it all in
         * anyway, and faults on the backing store itself are very expensive
         * once we go SMP (contend a lot).  So do it now.
         */
        if (prezeromem)
                bzero(dmap_min_address, Maxmem_bytes);

        /*
         * Bootstrap the kernel_pmap
         */
        firstfree = NULL;
        pmap_bootstrap((vm_paddr_t *)&firstfree, (int64_t)base);

        mcontrol(base, KERNEL_KVA_SIZE, MADV_SETMAP,
                 0 | VPTE_RW | VPTE_V);

        /*
         * phys_avail[] represents unallocated physical memory.  MI code
         * will use phys_avail[] to create the vm_page array.
         */
        phys_avail[0].phys_beg = (vm_paddr_t)firstfree;
        phys_avail[0].phys_beg = (phys_avail[0].phys_beg + PAGE_MASK) &
                                 ~(vm_paddr_t)PAGE_MASK;
        phys_avail[0].phys_end = Maxmem_bytes;

#if 0 /* JGV */
        /*
         * (virtual_start, virtual_end) represent unallocated kernel virtual
         * memory.  MI code will create kernel_map using these parameters.
         */
        virtual_start = KvaStart + (long)firstfree;
        virtual_start = (virtual_start + PAGE_MASK) & ~(vm_offset_t)PAGE_MASK;
        virtual_end = KvaStart + KERNEL_KVA_SIZE;
#endif

        /*
         * pmap_growkernel() will set the correct value.
         */
        kernel_vm_end = 0;

        /*
         * Allocate space for process 0's UAREA.
         */
        proc0paddr = (void *)virtual_start;
        for (i = 0; i < UPAGES; ++i) {
                pmap_kenter_quick(virtual_start, phys_avail[0].phys_beg);
                virtual_start += PAGE_SIZE;
                phys_avail[0].phys_beg += PAGE_SIZE;
        }

        /*
         * crashdumpmap
         */
        crashdumpmap = virtual_start;
        virtual_start += MAXDUMPPGS * PAGE_SIZE;

        /*
         * msgbufp maps the system message buffer
         */
        assert((MSGBUF_SIZE & PAGE_MASK) == 0);
        msgbufp = (void *)virtual_start;
        for (i = 0; i < (MSGBUF_SIZE >> PAGE_SHIFT); ++i) {
                pmap_kenter_quick(virtual_start, phys_avail[0].phys_beg);
                virtual_start += PAGE_SIZE;
                phys_avail[0].phys_beg += PAGE_SIZE;
        }
        msgbufinit(msgbufp, MSGBUF_SIZE);

        /*
         * used by kern_memio for /dev/mem access
         */
        ptvmmap = (caddr_t)virtual_start;
        virtual_start += PAGE_SIZE;
}

/*
 * Map the per-cpu globaldata for cpu #0.  Allocate the space using
 * virtual_start and phys_avail[0]
 */
static
void
init_globaldata(void)
{
        int i;
        vm_paddr_t pa;
        vm_offset_t va;

        /*
         * Reserve enough KVA to cover possible cpus.  This is a considerable
         * amount of KVA since the privatespace structure includes two
         * whole page table mappings.
         */
        virtual_start = (virtual_start + SEG_MASK) & ~(vm_offset_t)SEG_MASK;
        CPU_prvspace = (void *)virtual_start;
        virtual_start += sizeof(struct privatespace) * SMP_MAXCPU;

        /*
         * Allocate enough physical memory to cover the mdglobaldata
         * portion of the space and the idle stack and map the pages
         * into KVA.  For cpu #0 only.
         */
        for (i = 0; i < sizeof(struct mdglobaldata); i += PAGE_SIZE) {
                pa = phys_avail[0].phys_beg;
                va = (vm_offset_t)&CPU_prvspace[0].mdglobaldata + i;
                pmap_kenter_quick(va, pa);
                phys_avail[0].phys_beg += PAGE_SIZE;
        }
        for (i = 0; i < sizeof(CPU_prvspace[0].idlestack); i += PAGE_SIZE) {
                pa = phys_avail[0].phys_beg;
                va = (vm_offset_t)&CPU_prvspace[0].idlestack + i;
                pmap_kenter_quick(va, pa);
                phys_avail[0].phys_beg += PAGE_SIZE;
        }

        /*
         * Setup the %gs for cpu #0.  The mycpu macro works after this
         * point.  Note that %fs is used by pthreads.
         */
        tls_set_gs(&CPU_prvspace[0], sizeof(struct privatespace));
}


/*
 * Initialize pool tokens and other necessary locks
 */
static void
init_locks(void)
{

        /*
         * Get the initial mplock with a count of 1 for the BSP.
         * This uses a LOGICAL cpu ID, ie BSP == 0.
         */
        cpu_get_initial_mplock();

        /* our token pool needs to work early */
        lwkt_token_pool_init();

}


/*
 * Initialize very low level systems including thread0, proc0, etc.
 */
static
void
init_vkernel(void)
{
        struct mdglobaldata *gd;

        gd = &CPU_prvspace[0].mdglobaldata;
        bzero(gd, sizeof(*gd));

        gd->mi.gd_curthread = &thread0;
        thread0.td_gd = &gd->mi;
        ncpus = 1;
        ncpus_fit = 1;  /* rounded up power of 2 */
        /* ncpus_fit_mask are 0 */
        init_param1();
        gd->mi.gd_prvspace = &CPU_prvspace[0];
        mi_gdinit(&gd->mi, 0);
        cpu_gdinit(gd, 0);
        mi_proc0init(&gd->mi, proc0paddr);
        lwp0.lwp_md.md_regs = &proc0_tf;

        init_locks();
        cninit();
        rand_initialize();
#if 0   /* #ifdef DDB */
        kdb_init();
        if (boothowto & RB_KDB)
                Debugger("Boot flags requested debugger");
#endif
        identcpu();
#if 0
        initializecpu();        /* Initialize CPU registers */
#endif
        init_param2((phys_avail[0].phys_end -
                     phys_avail[0].phys_beg) / PAGE_SIZE);

#if 0
        /*
         * Map the message buffer
         */
        for (off = 0; off < round_page(MSGBUF_SIZE); off += PAGE_SIZE)
                pmap_kenter((vm_offset_t)msgbufp + off, avail_end + off);
        msgbufinit(msgbufp, MSGBUF_SIZE);
#endif
#if 0
        thread0.td_pcb_cr3 ... MMU
        lwp0.lwp_md.md_regs = &proc0_tf;
#endif
}

/*
 * Filesystem image paths for the virtual kernel are optional.
 * If specified they each should point to a disk image,
 * the first of which will become the root disk.
 *
 * The virtual kernel caches data from our 'disk' just like a normal kernel,
 * so we do not really want the real kernel to cache the data too.  Use
 * O_DIRECT to remove the duplication.
 */
static
void
init_disk(char **diskExp, int *diskFlags, int diskFileNum, enum vkdisk_type type)
{
        char *serno;
        int i;

        if (diskFileNum == 0)
                return;

        for (i=0; i < diskFileNum; i++){
                char *fname;
                fname = diskExp[i];

                if (fname == NULL) {
                        warnx("Invalid argument to '-r'");
                        continue;
                }
                /*
                 * Check for a serial number for the virtual disk
                 * passed from the command line.
                 */
                serno = fname;
                strsep(&serno, ":");

                if (DiskNum < VKDISK_MAX) {
                        struct stat st;
                        struct vkdisk_info *info = NULL;
                        int fd;
                        size_t l = 0;

                        if (type == VKD_DISK)
                            fd = open(fname, O_RDWR|O_DIRECT, 0644);
                        else
                            fd = open(fname, O_RDONLY|O_DIRECT, 0644);
                        if (fd < 0 || fstat(fd, &st) < 0) {
                                err(1, "Unable to open/create %s", fname);
                                /* NOT REACHED */
                        }
                        if (S_ISREG(st.st_mode) && (diskFlags[i] & 1) == 0) {
                                if (flock(fd, LOCK_EX|LOCK_NB) < 0) {
                                        errx(1, "Disk image %s is already "
                                                "in use\n", fname);
                                        /* NOT REACHED */
                                }
                        }

                        info = &DiskInfo[DiskNum];
                        l = strlen(fname);

                        info->unit = i;
                        info->fd = fd;
                        info->type = type;
                        info->flags = diskFlags[i];
                        memcpy(info->fname, fname, l);
                        info->serno = NULL;
                        if (serno) {
                                if ((info->serno = malloc(SERNOLEN)) != NULL)
                                        strlcpy(info->serno, serno, SERNOLEN);
                                else
                                        warnx("Couldn't allocate memory for the operation");
                        }

                        if (DiskNum == 0) {
                                if (type == VKD_CD) {
                                        rootdevnames[0] = "cd9660:vcd0";
                                } else if (type == VKD_DISK) {
                                        rootdevnames[0] = "ufs:vkd0s0a";
                                        rootdevnames[1] = "ufs:vkd0s1a";
                                }
                        }

                        DiskNum++;
                } else {
                        warnx("vkd%d (%s) > VKDISK_MAX", DiskNum, fname);
                        continue;
                }
        }
}

static
int
netif_set_tapflags(int tap_unit, int f, int s)
{
        struct ifreq ifr;
        int flags;

        bzero(&ifr, sizeof(ifr));

        snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tap%d", tap_unit);
        if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
                warn("tap%d: ioctl(SIOCGIFFLAGS) failed", tap_unit);
                return -1;
        }

        /*
         * Adjust if_flags
         *
         * If the flags are already set/cleared, then we return
         * immediately to avoid extra syscalls
         */
        flags = (ifr.ifr_flags & 0xffff) | (ifr.ifr_flagshigh << 16);
        if (f < 0) {
                /* Turn off flags */
                f = -f;
                if ((flags & f) == 0)
                        return 0;
                flags &= ~f;
        } else {
                /* Turn on flags */
                if (flags & f)
                        return 0;
                flags |= f;
        }

        /*
         * Fix up ifreq.ifr_name, since it may be trashed
         * in previous ioctl(SIOCGIFFLAGS)
         */
        snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tap%d", tap_unit);

        ifr.ifr_flags = flags & 0xffff;
        ifr.ifr_flagshigh = flags >> 16;
        if (ioctl(s, SIOCSIFFLAGS, &ifr) < 0) {
                warn("tap%d: ioctl(SIOCSIFFLAGS) failed", tap_unit);
                return -1;
        }
        return 0;
}

static
int
netif_set_tapaddr(int tap_unit, in_addr_t addr, in_addr_t mask, int s)
{
        struct ifaliasreq ifra;
        struct sockaddr_in *in;

        bzero(&ifra, sizeof(ifra));
        snprintf(ifra.ifra_name, sizeof(ifra.ifra_name), "tap%d", tap_unit);

        /* Setup address */
        in = (struct sockaddr_in *)&ifra.ifra_addr;
        in->sin_family = AF_INET;
        in->sin_len = sizeof(*in);
        in->sin_addr.s_addr = addr;

        if (mask != 0) {
                /* Setup netmask */
                in = (struct sockaddr_in *)&ifra.ifra_mask;
                in->sin_len = sizeof(*in);
                in->sin_addr.s_addr = mask;
        }

        if (ioctl(s, SIOCAIFADDR, &ifra) < 0) {
                warn("tap%d: ioctl(SIOCAIFADDR) failed", tap_unit);
                return -1;
        }
        return 0;
}

static
int
netif_add_tap2brg(int tap_unit, const char *ifbridge, int s)
{
        struct ifbreq ifbr;
        struct ifdrv ifd;

        bzero(&ifbr, sizeof(ifbr));
        snprintf(ifbr.ifbr_ifsname, sizeof(ifbr.ifbr_ifsname),
                 "tap%d", tap_unit);

        bzero(&ifd, sizeof(ifd));
        strlcpy(ifd.ifd_name, ifbridge, sizeof(ifd.ifd_name));
        ifd.ifd_cmd = BRDGADD;
        ifd.ifd_len = sizeof(ifbr);
        ifd.ifd_data = &ifbr;

        if (ioctl(s, SIOCSDRVSPEC, &ifd) < 0) {
                /*
                 * 'errno == EEXIST' means that the tap(4) is already
                 * a member of the bridge(4)
                 */
                if (errno != EEXIST) {
                        warn("ioctl(%s, SIOCSDRVSPEC) failed", ifbridge);
                        return -1;
                }
        }
        return 0;
}

#define TAPDEV_OFLAGS   (O_RDWR | O_NONBLOCK)

/*
 * Locate the first unused tap(4) device file if auto mode is requested,
 * or open the user supplied device file, and bring up the corresponding
 * tap(4) interface.
 *
 * NOTE: Only tap(4) device file is supported currently
 */
static
int
netif_open_tap(const char *netif, int *tap_unit, int s)
{
        char tap_dev[MAXPATHLEN];
        int tap_fd, failed;
        struct stat st;
        char *dname;

        *tap_unit = -1;

        if (strcmp(netif, "auto") == 0) {
                /*
                 * Find first unused tap(4) device file
                 */
                tap_fd = open("/dev/tap", TAPDEV_OFLAGS);
                if (tap_fd < 0) {
                        warnc(errno, "Unable to find a free tap(4)");
                        return -1;
                }
        } else {
                /*
                 * User supplied tap(4) device file or unix socket.
                 */
                if (netif[0] == '/')    /* Absolute path */
                        strlcpy(tap_dev, netif, sizeof(tap_dev));
                else
                        snprintf(tap_dev, sizeof(tap_dev), "/dev/%s", netif);

                tap_fd = open(tap_dev, TAPDEV_OFLAGS);

                /*
                 * If we cannot open normally try to connect to it.
                 */
                if (tap_fd < 0)
                        tap_fd = unix_connect(tap_dev);

                if (tap_fd < 0) {
                        warn("Unable to open %s", tap_dev);
                        return -1;
                }
        }

        /*
         * Check whether the device file is a tap(4)
         */
        if (fstat(tap_fd, &st) < 0) {
                failed = 1;
        } else if (S_ISCHR(st.st_mode)) {
                dname = fdevname(tap_fd);
                if (dname)
                        dname = strstr(dname, "tap");
                if (dname) {
                        /*
                         * Bring up the corresponding tap(4) interface
                         */
                        *tap_unit = strtol(dname + 3, NULL, 10);
                        printf("TAP UNIT %d\n", *tap_unit);
                        if (netif_set_tapflags(*tap_unit, IFF_UP, s) == 0)
                                failed = 0;
                        else
                                failed = 1;
                } else {
                        failed = 1;
                }
        } else if (S_ISSOCK(st.st_mode)) {
                /*
                 * Special socket connection (typically to vknet).  We
                 * do not have to do anything.
                 */
                failed = 0;
        } else {
                failed = 1;
        }

        if (failed) {
                warnx("%s is not a tap(4) device or socket", tap_dev);
                close(tap_fd);
                tap_fd = -1;
                *tap_unit = -1;
        }
        return tap_fd;
}

static int
unix_connect(const char *path)
{
        struct sockaddr_un sunx;
        int len;
        int net_fd;
        int sndbuf = 262144;
        struct stat st;

        snprintf(sunx.sun_path, sizeof(sunx.sun_path), "%s", path);
        len = offsetof(struct sockaddr_un, sun_path[strlen(sunx.sun_path)]);
        ++len;  /* include nul */
        sunx.sun_family = AF_UNIX;
        sunx.sun_len = len;

        net_fd = socket(AF_UNIX, SOCK_SEQPACKET, 0);
        if (net_fd < 0)
                return(-1);
        if (connect(net_fd, (void *)&sunx, len) < 0) {
                close(net_fd);
                return(-1);
        }
        setsockopt(net_fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf));
        if (fstat(net_fd, &st) == 0)
                printf("Network socket buffer: %ld bytes\n", st.st_blksize);
        fcntl(net_fd, F_SETFL, O_NONBLOCK);
        return(net_fd);
}

#undef TAPDEV_MAJOR
#undef TAPDEV_MINOR
#undef TAPDEV_OFLAGS

/*
 * Following syntax is supported,
 * 1) x.x.x.x             tap(4)'s address is x.x.x.x
 *
 * 2) x.x.x.x/z           tap(4)'s address is x.x.x.x
 *                        tap(4)'s netmask len is z
 *
 * 3) x.x.x.x:y.y.y.y     tap(4)'s address is x.x.x.x
 *                        pseudo netif's address is y.y.y.y
 *
 * 4) x.x.x.x:y.y.y.y/z   tap(4)'s address is x.x.x.x
 *                        pseudo netif's address is y.y.y.y
 *                        tap(4) and pseudo netif's netmask len are z
 *
 * 5) bridgeX             tap(4) will be added to bridgeX
 *
 * 6) bridgeX:y.y.y.y     tap(4) will be added to bridgeX
 *                        pseudo netif's address is y.y.y.y
 *
 * 7) bridgeX:y.y.y.y/z   tap(4) will be added to bridgeX
 *                        pseudo netif's address is y.y.y.y
 *                        pseudo netif's netmask len is z
 */
static
int
netif_init_tap(int tap_unit, in_addr_t *addr, in_addr_t *mask, int s)
{
        in_addr_t tap_addr, netmask, netif_addr;
        int next_netif_addr;
        char *tok, *masklen_str, *ifbridge;

        *addr = 0;
        *mask = 0;

        tok = strtok(NULL, ":/");
        if (tok == NULL) {
                /*
                 * Nothing special, simply use tap(4) as backend
                 */
                return 0;
        }

        if (inet_pton(AF_INET, tok, &tap_addr) > 0) {
                /*
                 * tap(4)'s address is supplied
                 */
                ifbridge = NULL;

                /*
                 * If there is next token, then it may be pseudo
                 * netif's address or netmask len for tap(4)
                 */
                next_netif_addr = 0;
        } else {
                /*
                 * Not tap(4)'s address, assume it as a bridge(4)
                 * iface name
                 */
                tap_addr = 0;
                ifbridge = tok;

                /*
                 * If there is next token, then it must be pseudo
                 * netif's address
                 */
                next_netif_addr = 1;
        }

        netmask = netif_addr = 0;

        tok = strtok(NULL, ":/");
        if (tok == NULL)
                goto back;

        if (inet_pton(AF_INET, tok, &netif_addr) <= 0) {
                if (next_netif_addr) {
                        warnx("Invalid pseudo netif address: %s", tok);
                        return -1;
                }
                netif_addr = 0;

                /*
                 * Current token is not address, then it must be netmask len
                 */
                masklen_str = tok;
        } else {
                /*
                 * Current token is pseudo netif address, if there is next token
                 * it must be netmask len
                 */
                masklen_str = strtok(NULL, "/");
        }

        /* Calculate netmask */
        if (masklen_str != NULL) {
                u_long masklen;

                masklen = strtoul(masklen_str, NULL, 10);
                if (masklen < 32 && masklen > 0) {
                        netmask =
                            htonl(rounddown2(0xffffffff, 1LL << (32 - masklen)));
                } else {
                        warnx("Invalid netmask len: %lu", masklen);
                        return -1;
                }
        }

        /* Make sure there is no more token left */
        if (strtok(NULL, ":/") != NULL) {
                warnx("Invalid argument to '-I'");
                return -1;
        }

back:
        if (tap_unit < 0) {
                /* Do nothing */
        } else if (ifbridge == NULL) {
                /* Set tap(4) address/netmask */
                if (netif_set_tapaddr(tap_unit, tap_addr, netmask, s) < 0)
                        return -1;
        } else {
                /* Tie tap(4) to bridge(4) */
                if (netif_add_tap2brg(tap_unit, ifbridge, s) < 0)
                        return -1;
        }

        *addr = netif_addr;
        *mask = netmask;
        return 0;
}

/*
 * NetifInfo[] will be filled for pseudo netif initialization.
 * NetifNum will be bumped to reflect the number of valid entries
 * in NetifInfo[].
 */
static
void
init_netif(char *netifExp[], int netifExpNum)
{
        int i, s;
        char *tmp;

        if (netifExpNum == 0)
                return;

        s = socket(AF_INET, SOCK_DGRAM, 0);     /* for ioctl(SIOC) */
        if (s < 0)
                return;

        for (i = 0; i < netifExpNum; ++i) {
                struct vknetif_info *info;
                in_addr_t netif_addr, netif_mask;
                int tap_fd, tap_unit;
                char *netif;

                /* Extract MAC address if there is one */
                tmp = netifExp[i];
                strsep(&tmp, "=");

                netif = strtok(netifExp[i], ":");
                if (netif == NULL) {
                        warnx("Invalid argument to '-I'");
                        continue;
                }

                /*
                 * Open tap(4) device file and bring up the
                 * corresponding interface
                 */
                tap_fd = netif_open_tap(netif, &tap_unit, s);
                if (tap_fd < 0)
                        continue;

                /*
                 * Initialize tap(4) and get address/netmask
                 * for pseudo netif
                 *
                 * NB: Rest part of netifExp[i] is passed
                 *     to netif_init_tap() implicitly.
                 */
                if (netif_init_tap(tap_unit, &netif_addr, &netif_mask, s) < 0) {
                        /*
                         * NB: Closing tap(4) device file will bring
                         *     down the corresponding interface
                         */
                        close(tap_fd);
                        continue;
                }

                info = &NetifInfo[NetifNum];
                bzero(info, sizeof(*info));
                info->tap_fd = tap_fd;
                info->tap_unit = tap_unit;
                info->netif_addr = netif_addr;
                info->netif_mask = netif_mask;
                /*
                 * If tmp isn't NULL it means a MAC could have been
                 * specified so attempt to convert it.
                 * Setting enaddr to NULL will tell vke_attach() we
                 * need a pseudo-random MAC address.
                 */
                if (tmp != NULL) {
                        if ((info->enaddr = malloc(ETHER_ADDR_LEN)) == NULL)
                                warnx("Couldn't allocate memory for the operation");
                        else {
                                if ((kether_aton(tmp, info->enaddr)) == NULL) {
                                        free(info->enaddr);
                                        info->enaddr = NULL;
                                }
                        }
                }

                NetifNum++;
                if (NetifNum >= VKNETIF_MAX)    /* XXX will this happen? */
                        break;
        }
        close(s);
}

/*
 * Create the pid file and leave it open and locked while the vkernel is
 * running.  This allows a script to use /usr/bin/lockf to probe whether
 * a vkernel is still running (so as not to accidently kill an unrelated
 * process from a stale pid file).
 */
static
void
writepid(void)
{
        char buf[32];
        int fd;

        if (pid_file != NULL) {
                snprintf(buf, sizeof(buf), "%ld\n", (long)getpid());
                fd = open(pid_file, O_RDWR|O_CREAT|O_EXLOCK|O_NONBLOCK, 0666);
                if (fd < 0) {
                        if (errno == EWOULDBLOCK) {
                                perror("Failed to lock pidfile, "
                                       "vkernel already running");
                        } else {
                                perror("Failed to create pidfile");
                        }
                        exit(EX_SOFTWARE);
                }
                ftruncate(fd, 0);
                write(fd, buf, strlen(buf));
                /* leave the file open to maintain the lock */
        }
}

static
void
cleanpid( void )
{
        if (pid_file != NULL) {
                if (unlink(pid_file) < 0)
                        perror("Warning: couldn't remove pidfile");
        }
}

static
void
usage_err(const char *ctl, ...)
{
        va_list va;

        va_start(va, ctl);
        vfprintf(stderr, ctl, va);
        va_end(va);
        fprintf(stderr, "\n");
        exit(EX_USAGE);
}

static
void
usage_help(_Bool help)
{
        fprintf(stderr, "Usage: %s [-hsUvdt] [-c file] [-e name=value:name=value:...]\n"
            "\t[-i file] [-I interface[:address1[:address2][/netmask]]] [-l cpulock]\n"
            "\t[-m size] [-n numcpus[:lbits[:cbits]]]\n"
            "\t[-p file] [-r file]\n", save_av[0]);

        if (help)
                fprintf(stderr, "\nArguments:\n"
                    "\t-c\tSpecify a readonly CD-ROM image file to be used by the kernel.\n"
                    "\t-e\tSpecify an environment to be used by the kernel.\n"
                    "\t-h\tThis list of options.\n"
                    "\t-i\t(DEPRECATED) Memory is now always anonymous.\n"
                    "\t-I\tCreate a virtual network device.\n"
                    "\t-l\tSpecify which, if any, real CPUs to lock virtual CPUs to.\n"
                    "\t-m\tSpecify the amount of memory to be used by the kernel in bytes (required).\n"
                    "\t-n\tSpecify the number of CPUs and the topology you wish to emulate:\n"
                    "\t\t\tnumcpus - number of cpus\n"
                    "\t\t\tlbits - specify the number of bits within APICID(=CPUID)\n"
                    "\t\t\t        needed for representing the logical ID.\n"
                    "\t\t\t        Controls the number of threads/core:\n"
                    "\t\t\t        (0 bits - 1 thread, 1 bit - 2 threads).\n"
                    "\t\t\tcbits - specify the number of bits within APICID(=CPUID)\n"
                    "\t\t\t        needed for representing the core ID.\n"
                    "\t\t\t        Controls the number of cores/package:\n"
                    "\t\t\t        (0 bits - 1 core, 1 bit - 2 cores).\n"
                    "\t-p\tSpecify a file in which to store the process ID.\n"
                    "\t-r\tSpecify a R/W disk image file, iterates vkd0..n\n"
                    "\t-R\tSpecify a COW disk image file, iterates vkd0..n\n"
                    "\t-s\tBoot into single-user mode.\n"
                    "\t-t\tUse a precise host timer when calculating clock values.\n"
                    "\t-U\tEnable writing to kernel memory and module loading.\n"
                    "\t-v\tTurn on verbose booting.\n");

        exit(EX_USAGE);
}

void
cpu_smp_stopped(void)
{
}

void
cpu_reset(void)
{
        kprintf("cpu reset, rebooting vkernel\n");
        closefrom(3);
        cleanpid();
        exit(EX_VKERNEL_REBOOT);
}

void
cpu_halt(void)
{
        kprintf("cpu halt, exiting vkernel\n");
        cleanpid();
        exit(EX_OK);
}

void
setrealcpu(void)
{
        switch(lwp_cpu_lock) {
        case LCL_PER_CPU:
                if (bootverbose)
                        kprintf("Locking CPU%d to real cpu %d\n",
                                mycpuid, next_cpu);
                usched_set(getpid(), USCHED_SET_CPU, &next_cpu, sizeof(next_cpu));
                next_cpu++;
                if (next_cpu >= real_ncpus)
                        next_cpu = 0;
                break;
        case LCL_SINGLE_CPU:
                if (bootverbose)
                        kprintf("Locking CPU%d to real cpu %d\n",
                                mycpuid, next_cpu);
                usched_set(getpid(), USCHED_SET_CPU, &next_cpu, sizeof(next_cpu));
                break;
        default:
                /* do not map virtual cpus to real cpus */
                break;
        }
}

/*
 * Allocate and free memory for module loading.  The loaded module
 * has to be placed somewhere near the current kernel binary load
 * point or the relocations will not work.
 *
 * I'm not sure why this isn't working.
 */
int
vkernel_module_memory_alloc(vm_offset_t *basep, size_t bytes)
{
#if 1
        size_t xtra;
        xtra = (PAGE_SIZE - (vm_offset_t)sbrk(0)) & PAGE_MASK;
        *basep = (vm_offset_t)sbrk(xtra + bytes) + xtra;
        bzero((void *)*basep, bytes);
#else
        *basep = (vm_offset_t)mmap((void *)0x000000000, bytes,
                                   PROT_READ|PROT_WRITE|PROT_EXEC,
                                   MAP_ANON|MAP_SHARED, -1, 0);
        if ((void *)*basep == MAP_FAILED)
                return ENOMEM;
#endif
        return 0;
}

void
vkernel_module_memory_free(vm_offset_t base, size_t bytes)
{
#if 0
#if 0
        munmap((void *)base, bytes);
#endif
#endif
}

/*
 * VKERNEL64 implementation functions using ptrheads.
 */
void
vkernel_yield(void)
{
        pthread_yield();
}