/*-
 * Copyright (c) 2003 Kip Macy
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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/param.h>
#include <sys/proc.h>
#include <sys/module.h>
#include <sys/sysent.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/nlookup.h>

#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/signal.h>
#include <vm/vm_param.h>
#include <vm/vm.h>
#include <sys/imgact_elf.h>
#include <sys/procfs.h>

#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_extern.h>
#include <sys/mman.h>
#include <sys/sysmsg.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/malloc.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/vnode.h>
#include <machine/inttypes.h>
#include <machine/limits.h>
#include <machine/frame.h>
#include <sys/signalvar.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <machine/sigframe.h>
#include <sys/exec.h>
#include <sys/unistd.h>
#include <sys/time.h>
#include <sys/kern_syscall.h>
#include <sys/checkpoint.h>
#include <sys/mount.h>
#include <sys/ckpt.h>

#include <sys/mplock2.h>
#include <sys/file2.h>

static int elf_loadphdrs(struct file *fp,  Elf_Phdr *phdr, int numsegs);
static int elf_getnotes(struct lwp *lp, struct file *fp, size_t notesz);
static int elf_demarshalnotes(void *src, prpsinfo_t *psinfo,
                 prstatus_t *status, prfpregset_t *fpregset, int nthreads);
static int elf_loadnotes(struct lwp *, prpsinfo_t *, prstatus_t *,
                 prfpregset_t *);
static int elf_getsigs(struct lwp *lp, struct file *fp);
static int elf_getfiles(struct lwp *lp, struct file *fp);
static int elf_gettextvp(struct proc *p, struct file *fp);
static char *ckpt_expand_name(const char *name, uid_t uid, pid_t pid);

static int ckptgroup = 0;       /* wheel only, -1 for any group */
SYSCTL_INT(_kern, OID_AUTO, ckptgroup, CTLFLAG_RW, &ckptgroup, 0, "");

/* ref count to see how many processes that are being checkpointed */
static int chptinuse = 0;

static __inline
int
read_check(struct file *fp, void *buf, size_t nbyte)
{
        size_t nread;
        int error;

        PRINTF(("reading %zd bytes\n", nbyte));
        error = fp_read(fp, buf, nbyte, &nread, 1, UIO_SYSSPACE);
        if (error) {
                PRINTF(("read failed - %d", error));
        } else if (nread != nbyte) {
                PRINTF(("wanted to read %zd - read %zd\n", nbyte, nread));
                error = EINVAL;
        }
        return error;
}

static int
elf_gethdr(struct file *fp, Elf_Ehdr *ehdr)
{
        size_t nbyte = sizeof(Elf_Ehdr);
        int error;

        if ((error = read_check(fp, ehdr, nbyte)) != 0)
                goto done;
        if (!(ehdr->e_ehsize == sizeof(Elf_Ehdr))) {
                PRINTF(("wrong elf header size: %d\n"
                       "expected size        : %zd\n",
                       ehdr->e_ehsize, sizeof(Elf_Ehdr)));
                return EINVAL;
        }
        if (!(ehdr->e_phentsize == sizeof(Elf_Phdr))) {
                PRINTF(("wrong program header size: %d\n"
                       "expected size            : %zd\n",
                       ehdr->e_phentsize, sizeof(Elf_Phdr)));
                return EINVAL;
        }

        if (!(ehdr->e_ident[EI_MAG0] == ELFMAG0 &&
              ehdr->e_ident[EI_MAG1] == ELFMAG1 &&
              ehdr->e_ident[EI_MAG2] == ELFMAG2 &&
              ehdr->e_ident[EI_MAG3] == ELFMAG3 &&
              ehdr->e_ident[EI_CLASS] == ELF_CLASS &&
              ehdr->e_ident[EI_DATA] == ELF_DATA &&
              ehdr->e_ident[EI_VERSION] == EV_CURRENT &&
              ehdr->e_ident[EI_OSABI] == ELFOSABI_NONE &&
              ehdr->e_ident[EI_ABIVERSION] == 0)) {
                PRINTF(("bad elf header\n there are %d segments\n",
                       ehdr->e_phnum));
                return EINVAL;

        }
        PRINTF(("Elf header size:           %d\n", ehdr->e_ehsize));
        PRINTF(("Program header size:       %d\n", ehdr->e_phentsize));
        PRINTF(("Number of Program headers: %d\n", ehdr->e_phnum));
 done:
        return error;
}

static int
elf_getphdrs(struct file *fp, Elf_Phdr *phdr, size_t nbyte)
{
        int i;
        int error;
        int nheaders = nbyte/sizeof(Elf_Phdr);

        PRINTF(("reading phdrs section\n"));
        if ((error = read_check(fp, phdr, nbyte)) != 0)
                goto done;
        PRINTF(("headers section:\n"));
        for (i = 0; i < nheaders; i++) {
                PRINTF(("entry type:   %d\n", phdr[i].p_type));
                PRINTF(("file offset:  %jd\n", (intmax_t)phdr[i].p_offset));
                PRINTF(("virt address: %p\n", (uint32_t *)phdr[i].p_vaddr));
                PRINTF(("file size:    %jd\n", (intmax_t)phdr[i].p_filesz));
                PRINTF(("memory size:  %jd\n", (intmax_t)phdr[i].p_memsz));
                PRINTF(("\n"));
        }
 done:
        return error;
}


static int
elf_getnotes(struct lwp *lp, struct file *fp, size_t notesz)
{
        int error;
        int nthreads;
        char *note;
        prpsinfo_t *psinfo;
        prstatus_t *status;
        prfpregset_t *fpregset;

        nthreads = (notesz - sizeof(prpsinfo_t))/(sizeof(prstatus_t) +
                                                  sizeof(prfpregset_t));
        PRINTF(("reading notes header nthreads=%d\n", nthreads));
        if (nthreads <= 0 || nthreads > CKPT_MAXTHREADS)
                return EINVAL;

        psinfo  = kmalloc(sizeof(prpsinfo_t), M_TEMP, M_ZERO | M_WAITOK);
        status  = kmalloc(nthreads*sizeof(prstatus_t), M_TEMP, M_WAITOK);
        fpregset  = kmalloc(nthreads*sizeof(prfpregset_t), M_TEMP, M_WAITOK);
        note = kmalloc(notesz, M_TEMP, M_WAITOK);


        PRINTF(("reading notes section\n"));
        if ((error = read_check(fp, note, notesz)) != 0)
                goto done;
        error = elf_demarshalnotes(note, psinfo, status, fpregset, nthreads);
        if (error)
                goto done;
        /* fetch register state from notes */
        error = elf_loadnotes(lp, psinfo, status, fpregset);
 done:
        if (psinfo)
                kfree(psinfo, M_TEMP);
        if (status)
                kfree(status, M_TEMP);
        if (fpregset)
                kfree(fpregset, M_TEMP);
        if (note)
                kfree(note, M_TEMP);
        return error;
}

static int
ckpt_thaw_proc(struct lwp *lp, struct file *fp)
{
        struct proc *p = lp->lwp_proc;
        Elf_Phdr *phdr = NULL;
        Elf_Ehdr *ehdr = NULL;
        int error;
        size_t nbyte;

        TRACE_ENTER;

        ehdr = kmalloc(sizeof(Elf_Ehdr), M_TEMP, M_ZERO | M_WAITOK);

        if ((error = elf_gethdr(fp, ehdr)) != 0)
                goto done;
        nbyte = sizeof(Elf_Phdr) * ehdr->e_phnum;
        phdr = kmalloc(nbyte, M_TEMP, M_WAITOK);

        /* fetch description of program writable mappings */
        if ((error = elf_getphdrs(fp, phdr, nbyte)) != 0)
                goto done;

        /* fetch notes section containing register state */
        if ((error = elf_getnotes(lp, fp, phdr->p_filesz)) != 0)
                goto done;

        /* fetch program text vnodes */
        if ((error = elf_gettextvp(p, fp)) != 0)
                goto done;

        /* fetch signal disposition */
        if ((error = elf_getsigs(lp, fp)) != 0) {
                kprintf("failure in recovering signals\n");
                goto done;
        }

        /* fetch open files */
        if ((error = elf_getfiles(lp, fp)) != 0)
                goto done;

        /* handle mappings last in case we are reading from a socket */
        error = elf_loadphdrs(fp, phdr, ehdr->e_phnum);

        /*
         * Set the textvp to the checkpoint file and mark the vnode so
         * a future checkpointing of this checkpoint-restored program
         * will copy out the contents of the mappings rather then trying
         * to record the vnode info related to the checkpoint file, which
         * is likely going to be destroyed when the program is re-checkpointed.
         */
        if (error == 0 && fp->f_data && fp->f_type == DTYPE_VNODE) {
                if (p->p_textvp)
                        vrele(p->p_textvp);
                p->p_textvp = (struct vnode *)fp->f_data;
                vsetflags(p->p_textvp, VCKPT);
                vref(p->p_textvp);
        }
done:
        if (ehdr)
                kfree(ehdr, M_TEMP);
        if (phdr)
                kfree(phdr, M_TEMP);
        TRACE_EXIT;
        return error;
}

static int
elf_loadnotes(struct lwp *lp, prpsinfo_t *psinfo, prstatus_t *status,
           prfpregset_t *fpregset)
{
        struct proc *p = lp->lwp_proc;
        int error;

        /* validate status and psinfo */
        TRACE_ENTER;
        if (status->pr_version != PRSTATUS_VERSION ||
            status->pr_statussz != sizeof(prstatus_t) ||
            status->pr_gregsetsz != sizeof(gregset_t) ||
            status->pr_fpregsetsz != sizeof(fpregset_t) ||
            psinfo->pr_version != PRPSINFO_VERSION ||
            psinfo->pr_psinfosz != sizeof(prpsinfo_t)) {
                PRINTF(("status check failed\n"));
                error = EINVAL;
                goto done;
        }
        /* XXX lwp handle more than one lwp*/
        if ((error = set_regs(lp, &status->pr_reg)) != 0)
                goto done;
        error = set_fpregs(lp, fpregset);
        strlcpy(p->p_comm, psinfo->pr_fname, sizeof(p->p_comm));
        /* XXX psinfo->pr_psargs not yet implemented */
 done:
        TRACE_EXIT;
        return error;
}

static int
elf_getnote(void *src, size_t *off, const char *name, unsigned int type,
            void **desc, size_t descsz)
{
        Elf_Note note;
        int error;

        TRACE_ENTER;
        if (src == NULL) {
                error = EFAULT;
                goto done;
        }
        bcopy((char *)src + *off, &note, sizeof note);

        PRINTF(("at offset: %zd expected note of type: %d - got: %d\n",
               *off, type, note.n_type));
        *off += sizeof note;
        if (type != note.n_type) {
                TRACE_ERR;
                error = EINVAL;
                goto done;
        }
        if (strncmp(name, (char *) src + *off, note.n_namesz) != 0) {
                error = EINVAL;
                goto done;
        }
        *off += roundup2(note.n_namesz, sizeof(Elf_Size));
        if (note.n_descsz != descsz) {
                TRACE_ERR;
                error = EINVAL;
                goto done;
        }
        if (desc)
                bcopy((char *)src + *off, *desc, note.n_descsz);
        *off += roundup2(note.n_descsz, sizeof(Elf_Size));
        error = 0;
 done:
        TRACE_EXIT;
        return error;
}

static int
elf_demarshalnotes(void *src, prpsinfo_t *psinfo, prstatus_t *status,
                   prfpregset_t *fpregset, int nthreads)
{
        int i;
        int error;
        size_t off = 0;

        TRACE_ENTER;
        error = elf_getnote(src, &off, "CORE", NT_PRPSINFO,
                           (void **)&psinfo, sizeof(prpsinfo_t));
        if (error)
                goto done;
        error = elf_getnote(src, &off, "CORE", NT_PRSTATUS,
                           (void **)&status, sizeof(prstatus_t));
        if (error)
                goto done;
        error = elf_getnote(src, &off, "CORE", NT_FPREGSET,
                           (void **)&fpregset, sizeof(prfpregset_t));
        if (error)
                goto done;

        /*
         * The remaining portion needs to be an integer multiple
         * of prstatus_t and prfpregset_t
         */
        for (i = 0 ; i < nthreads - 1; i++) {
                status++; fpregset++;
                error = elf_getnote(src, &off, "CORE", NT_PRSTATUS,
                                   (void **)&status, sizeof (prstatus_t));
                if (error)
                        goto done;
                error = elf_getnote(src, &off, "CORE", NT_FPREGSET,
                                   (void **)&fpregset, sizeof(prfpregset_t));
                if (error)
                        goto done;
        }

 done:
        TRACE_EXIT;
        return error;
}


static int
mmap_phdr(struct file *fp, Elf_Phdr *phdr)
{
        int error;
        size_t len;
        int prot;
        void *addr;
        int flags;
        off_t pos;

        TRACE_ENTER;
        pos = phdr->p_offset;
        len = phdr->p_filesz;
        addr = (void *)phdr->p_vaddr;
        flags = MAP_FIXED | MAP_NOSYNC | MAP_PRIVATE;
        prot = 0;
        if (phdr->p_flags & PF_R)
                prot |= PROT_READ;
        if (phdr->p_flags & PF_W)
                prot |= PROT_WRITE;
        if (phdr->p_flags & PF_X)
                prot |= PROT_EXEC;
        if ((error = fp_mmap(addr, len, prot, flags, fp, pos, &addr)) != 0) {
                PRINTF(("mmap failed: %d\n", error);       );
        }
        PRINTF(("map @%08"PRIxPTR"-%08"PRIxPTR" fileoff %08x-%08x\n", (uintptr_t)addr,
                   (uintptr_t)((char *)addr + len), (int)pos, (int)(pos + len)));
        TRACE_EXIT;
        return error;
}

/*
 * Load memory mapped segments.  The segments are backed by the checkpoint
 * file.
 */
static int
elf_loadphdrs(struct file *fp, Elf_Phdr *phdr, int numsegs)
{
        int i;
        int error = 0;

        TRACE_ENTER;
        for (i = 1; i < numsegs; i++)  {
                if ((error = mmap_phdr(fp, &phdr[i])) != 0)
                        break;
        }
        TRACE_EXIT;
        return error;
}

static int
elf_getsigs(struct lwp *lp, struct file *fp)
{
        struct proc *p = lp->lwp_proc;
        int error;
        struct ckpt_siginfo *csi;

        TRACE_ENTER;
        csi = kmalloc(sizeof(struct ckpt_siginfo), M_TEMP, M_ZERO | M_WAITOK);
        if ((error = read_check(fp, csi, sizeof(struct ckpt_siginfo))) != 0)
                goto done;

        if (csi->csi_ckptpisz != sizeof(struct ckpt_siginfo)) {
                TRACE_ERR;
                error = EINVAL;
                goto done;
        }
        bcopy(&csi->csi_sigacts, p->p_sigacts, sizeof(struct sigacts));
        bcopy(&csi->csi_itimerval, &p->p_realtimer, sizeof(struct itimerval));
        SIG_CANTMASK(csi->csi_sigmask);
        /* XXX lwp handle more than one lwp */
        bcopy(&csi->csi_sigmask, &lp->lwp_sigmask, sizeof(sigset_t));
        p->p_sigparent = csi->csi_sigparent;
 done:
        if (csi)
                kfree(csi, M_TEMP);
        TRACE_EXIT;
        return error;
}

/*
 * Returns a locked, refd vnode
 */
static int
ckpt_fhtovp(fhandle_t *fh, struct vnode **vpp)
{
        struct mount *mp;
        int error;

        TRACE_ENTER;
        mp = vfs_getvfs(&fh->fh_fsid);

        if (!mp) {
                TRACE_ERR;
                PRINTF(("failed to get mount - ESTALE\n"));
                TRACE_EXIT;
                return ESTALE;
        }
        error = VFS_FHTOVP(mp, NULL, &fh->fh_fid, vpp);
        mount_drop(mp);
        if (error) {
                PRINTF(("failed with: %d\n", error));
                TRACE_ERR;
        }
        TRACE_EXIT;
        return error;
}

static int
mmap_vp(struct vn_hdr *vnh)
{
        struct vnode *vp;
        Elf_Phdr *phdr;
        struct file *fp;
        int error;
        TRACE_ENTER;

        phdr = &vnh->vnh_phdr;

        if ((error = ckpt_fhtovp(&vnh->vnh_fh, &vp)) != 0)
                return error;
        /*
         * XXX O_RDONLY -> or O_RDWR if file is PROT_WRITE, MAP_SHARED
         */
        if ((error = fp_vpopen(vp, O_RDONLY, &fp)) != 0) {
                vput(vp);
                return error;
        }
        error = mmap_phdr(fp, phdr);
        fp_close(fp);
        TRACE_EXIT;
        return error;
}


static int
elf_gettextvp(struct proc *p, struct file *fp)
{
        int i;
        int error;
        int vpcount;
        struct ckpt_vminfo vminfo;
        struct vn_hdr *vnh = NULL;

        TRACE_ENTER;
        if ((error = read_check(fp, &vminfo, sizeof(vminfo))) != 0)
                goto done;
        if (vminfo.cvm_dsize < 0 ||
            vminfo.cvm_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur ||
            vminfo.cvm_tsize < 0 ||
            (u_quad_t)vminfo.cvm_tsize > maxtsiz ||
            vminfo.cvm_daddr >= (caddr_t)VM_MAX_USER_ADDRESS ||
            vminfo.cvm_taddr >= (caddr_t)VM_MAX_USER_ADDRESS
        ) {
            error = ERANGE;
            goto done;
        }

        vmspace_exec(p, NULL);
        p->p_vmspace->vm_daddr = vminfo.cvm_daddr;
        p->p_vmspace->vm_dsize = ctob(vminfo.cvm_dsize);        /* in bytes */
        p->p_vmspace->vm_taddr = vminfo.cvm_taddr;
        p->p_vmspace->vm_tsize = ctob(vminfo.cvm_tsize);        /* in bytes */
        if ((error = read_check(fp, &vpcount, sizeof(int))) != 0)
                goto done;
        vnh = kmalloc(sizeof(struct vn_hdr) * vpcount, M_TEMP, M_WAITOK);
        if ((error = read_check(fp, vnh, sizeof(struct vn_hdr)*vpcount)) != 0)
                goto done;
        for (i = 0; i < vpcount; i++) {
                if ((error = mmap_vp(&vnh[i])) != 0)
                        goto done;
        }

 done:
        if (vnh)
                kfree(vnh, M_TEMP);
        TRACE_EXIT;
        return error;
}



/* place holder */
static int
elf_getfiles(struct lwp *lp, struct file *fp)
{
        int error;
        int i;
        int filecount;
        int fd;
        struct ckpt_filehdr filehdr;
        struct ckpt_fileinfo *cfi_base = NULL;
        struct filedesc *fdp = lp->lwp_proc->p_fd;
        struct vnode *vp;
        struct file *tempfp;
        struct file *ofp;

        TRACE_ENTER;
        if ((error = read_check(fp, &filehdr, sizeof(filehdr))) != 0)
                goto done;
        filecount = filehdr.cfh_nfiles;
        cfi_base = kmalloc(filecount*sizeof(struct ckpt_fileinfo), M_TEMP, M_WAITOK);
        error = read_check(fp, cfi_base, filecount*sizeof(struct ckpt_fileinfo));
        if (error)
                goto done;

        /*
         * Close all file descriptors >= 3.  These descriptors are from the
         * checkpt(1) program itself and should not be retained.
         *
         * XXX we need a flag so a checkpoint restore can opt to supply the
         * descriptors, or the non-regular-file descripors.
         */
        for (i = 3; i < fdp->fd_nfiles; ++i)
                kern_close(i);

        /*
         * Scan files to load
         */
        for (i = 0; i < filecount; i++) {
                struct ckpt_fileinfo *cfi= &cfi_base[i];
                /*
                 * Ignore placeholder entries where cfi_index is less then
                 * zero.  This will occur if the elf core dump code thinks
                 * it can save a vnode but winds up not being able to.
                 */
                if (cfi->cfi_index < 0)
                        continue;

                /*
                 * Restore a saved file descriptor.  If CKFIF_ISCKPTFD is
                 * set the descriptor represents the checkpoint file itself,
                 * probably due to the user calling sys_checkpoint().  We
                 * want to use the fp being used to restore the checkpoint
                 * instead of trying to restore the original filehandle.
                 */
                if (cfi->cfi_ckflags & CKFIF_ISCKPTFD) {
                        fhold(fp);
                        tempfp = fp;
                        error = 0;
                } else {
                        error = ckpt_fhtovp(&cfi->cfi_fh, &vp);
                        if (error == 0) {
                                error = fp_vpopen(vp, OFLAGS(cfi->cfi_flags),
                                                  &tempfp);
                                if (error)
                                        vput(vp);
                        }
                }
                if (error)
                        break;
                tempfp->f_offset = cfi->cfi_offset;

                /*
                 * If overwriting a descriptor close the old descriptor.  This
                 * only occurs if the saved core saved descriptors that we
                 * have not already closed.
                 */
                if (cfi->cfi_index < fdp->fd_nfiles &&
                    (ofp = fdp->fd_files[cfi->cfi_index].fp) != NULL) {
                        kern_close(cfi->cfi_index);
                }

                /*
                 * Allocate the descriptor we want.
                 */
                if (fdalloc(lp->lwp_proc, cfi->cfi_index, &fd) != 0) {
                        PRINTF(("can't currently restore fd: %d\n",
                               cfi->cfi_index));
                        fp_close(fp);
                        goto done;
                }
                KKASSERT(fd == cfi->cfi_index);
                fsetfd(fdp, tempfp, fd);
                fdrop(tempfp);
                cfi++;
                PRINTF(("restoring %d\n", cfi->cfi_index));
        }

 done:
        if (cfi_base)
                kfree(cfi_base, M_TEMP);
        TRACE_EXIT;
        return error;
}

static int
ckpt_freeze_proc(struct lwp *lp, struct file *fp)
{
        struct proc *p = lp->lwp_proc;
        rlim_t limit;
        int error;

        lwkt_gettoken(&p->p_token);     /* needed for proc_*() calls */

        PRINTF(("calling generic_elf_coredump\n"));
        limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
        if (limit) {
                if (p->p_stat != SCORE) {
                        proc_stop(p, SCORE);
                        while (p->p_nstopped < p->p_nthreads - 1)
                                tsleep(&p->p_nstopped, 0, "freeze", 1);
                        error = generic_elf_coredump(lp, SIGCKPT, fp, limit);
                        proc_unstop(p, SCORE);
                } else {
                        error = ERANGE;
                }
        } else {
                error = ERANGE;
        }
        lwkt_reltoken(&p->p_token);
        return error;
}

/*
 * MPALMOSTSAFE
 */
int
sys_sys_checkpoint(struct sysmsg *sysmsg,
                   const struct sys_checkpoint_args *uap)
{
        int error = 0;
        struct thread *td = curthread;
        struct proc *p = td->td_proc;
        struct file *fp;

        /*
         * Only certain groups (to reduce our security exposure).  -1
         * allows any group.
         */
        if (ckptgroup >= 0 && groupmember(ckptgroup, td->td_ucred) == 0)
                return (EPERM);

        /*
         * For now we can only checkpoint the current process
         */
        if (uap->pid != -1 && uap->pid != p->p_pid)
                return (EINVAL);

        get_mplock();

        switch (uap->type) {
        case CKPT_FREEZE:
                fp = NULL;
                if (uap->fd == -1 && uap->pid == (pid_t)-1)
                        error = checkpoint_signal_handler(td->td_lwp);
                else if ((fp = holdfp(td, uap->fd, FWRITE)) == NULL)
                        error = EBADF;
                else
                        error = ckpt_freeze_proc(td->td_lwp, fp);
                if (fp)
                        dropfp(td, uap->fd, fp);
                break;
        case CKPT_THAW:
                if (uap->pid != -1) {
                        error = EINVAL;
                        break;
                }
                if ((fp = holdfp(td, uap->fd, FREAD)) == NULL) {
                        error = EBADF;
                        break;
                }
                sysmsg->sysmsg_result = uap->retval;
                error = ckpt_thaw_proc(td->td_lwp, fp);
                dropfp(td, uap->fd, fp);
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }
        rel_mplock();
        return error;
}

int
checkpoint_signal_handler(struct lwp *lp)
{
        struct thread *td = lp->lwp_thread;
        struct proc *p = lp->lwp_proc;
        char *buf;
        struct file *fp;
        struct nlookupdata nd;
        int error;

        chptinuse++;

        /*
         * Being able to checkpoint an suid or sgid program is not a good
         * idea.
         */
        if (sugid_coredump == 0 && (p->p_flags & P_SUGID)) {
                chptinuse--;
                return (EPERM);
        }

        buf = ckpt_expand_name(p->p_comm, td->td_ucred->cr_uid, p->p_pid);
        if (buf == NULL) {
                chptinuse--;
                return (ENOMEM);
        }

        log(LOG_INFO, "pid %d (%s), uid %d: checkpointing to %s\n",
                p->p_pid, p->p_comm,
                (td->td_ucred ? td->td_ucred->cr_uid : -1),
                buf);

        PRINTF(("ckpt handler called, using '%s'\n", buf));

        /*
         * Use the same safety flags that the coredump code uses.  Remove
         * any previous checkpoint file before writing out the new one in
         * case we are re-checkpointing a program that had been checkpt
         * restored.  Otherwise we will corrupt the program space (which is
         * made up of mmap()ings of the previous checkpoint file) while we
         * write out the new one.
         */
        error = nlookup_init(&nd, buf, UIO_SYSSPACE, 0);
        if (error == 0)
                error = kern_unlink(&nd);
        nlookup_done(&nd);
        error = fp_open(buf, O_WRONLY|O_CREAT|O_TRUNC|O_NOFOLLOW, 0600, &fp);
        if (error == 0) {
                error = ckpt_freeze_proc(lp, fp);
                fp_close(fp);
        } else {
                kprintf("checkpoint failed with open - error: %d\n", error);
        }
        kfree(buf, M_TEMP);
        chptinuse--;
        return (error);
}

static char ckptfilename[MAXPATHLEN] = {"%N.ckpt"};
SYSCTL_STRING(_kern, OID_AUTO, ckptfile, CTLFLAG_RW, ckptfilename,
              sizeof(ckptfilename), "process checkpoint name format string");

/*
 * expand_name(name, uid, pid)
 * Expand the name described in corefilename, using name, uid, and pid.
 * corefilename is a kprintf-like string, with three format specifiers:
 *      %N      name of process ("name")
 *      %P      process id (pid)
 *      %U      user id (uid)
 * For example, "%N.core" is the default; they can be disabled completely
 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
 * This is controlled by the sysctl variable kern.corefile (see above).
 *
 * -- taken from the coredump code
 */

static
char *
ckpt_expand_name(const char *name, uid_t uid, pid_t pid)
{
        char *temp;
        char *bp;
        char buf[11];           /* Buffer for pid/uid -- max 4B */
        int error;
        int i;
        int n;
        char *format = ckptfilename;
        size_t namelen;

        temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
        if (temp == NULL)
                return NULL;
        namelen = strlen(name);
        n = 0;
        if (ckptfilename[0] != '/') {
                if ((bp = kern_getcwd(temp, MAXPATHLEN - 1, &error)) == NULL) {
                        kfree(temp, M_TEMP);
                        return NULL;
                }
                n = strlen(bp);
                bcopy(bp, temp, n + 1); /* normalize location of the path */
                temp[n++] = '/';
                temp[n] = '\0';
        }
        for (i= 0; n < MAXPATHLEN && format[i]; i++) {
                int l;
                switch (format[i]) {
                case '%':       /* Format character */
                        i++;
                        switch (format[i]) {
                        case '%':
                                temp[n++] = '%';
                                break;
                        case 'N':       /* process name */
                                if ((n + namelen) > MAXPATHLEN) {
                                        log(LOG_ERR, "pid %d (%s), uid (%u):  Path `%s%s' is too long\n",
                                            pid, name, uid, temp, name);
                                        kfree(temp, M_TEMP);
                                        return NULL;
                                }
                                memcpy(temp+n, name, namelen);
                                n += namelen;
                                break;
                        case 'P':       /* process id */
                                l = ksprintf(buf, "%u", pid);
                                if ((n + l) > MAXPATHLEN) {
                                        log(LOG_ERR, "pid %d (%s), uid (%u):  Path `%s%s' is too long\n",
                                            pid, name, uid, temp, name);
                                        kfree(temp, M_TEMP);
                                        return NULL;
                                }
                                memcpy(temp+n, buf, l);
                                n += l;
                                break;
                        case 'U':       /* user id */
                                l = ksprintf(buf, "%u", uid);
                                if ((n + l) > MAXPATHLEN) {
                                        log(LOG_ERR, "pid %d (%s), uid (%u):  Path `%s%s' is too long\n",
                                            pid, name, uid, temp, name);
                                        kfree(temp, M_TEMP);
                                        return NULL;
                                }
                                memcpy(temp+n, buf, l);
                                n += l;
                                break;
                        default:
                                log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
                        }
                        break;
                default:
                        temp[n++] = format[i];
                }
        }
        temp[n] = '\0';
        return temp;
}