kern_symfile.c   [plain text]

/*
 * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
 * 
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */
/* Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
 *
 *	File:	bsd/kern/kern_symfile.c
 *
 *	This file contains creates a dummy symbol file for mach_kernel
 *	based on the symbol table information passed by the
 *	SecondaryLoader/PlatformExpert.  This allows us to correctly
 *	link other executables (drivers, etc) against the the kernel in
 *	cases where the kernel image on the root device does not match
 *      the live kernel. This can occur during net-booting where the
 *	actual kernel image is obtained from the network via tftp rather
 *	than the root device.
 *
 *      If a symbol table is available, then the file /mach.sym will be
 *	created containing a Mach Header and a LC_SYMTAB load command
 *	followed by the the symbol table data for mach_kernel.
 *
 * NOTE:	This file supports only 32 bit kernels at the present time;
 *		adding support for 64 bit kernels is possible, but is not
 *		necessary at the present time.
 *
 * HISTORY
 * 
 *	.
 */

#include <mach/vm_param.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/namei.h>
#include <sys/vnode_internal.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/timeb.h>
#include <sys/times.h>
#include <sys/acct.h>
#include <sys/file_internal.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/stat.h>
#include <sys/disk.h>
#include <sys/conf.h>

#include <mach-o/loader.h>
#include <mach-o/nlist.h>

#include <kern/kalloc.h>
#include <vm/vm_kern.h>
#include <pexpert/pexpert.h>
#include <IOKit/IOHibernatePrivate.h>

extern unsigned char 	rootdevice[];
extern struct mach_header _mh_execute_header;

static int kernel_symfile_opened = 0;
static int error_code = 0;

extern int  IODTGetLoaderInfo(char *key, void **infoAddr, int *infoSize);
extern void IODTFreeLoaderInfo(char *key, void *infoAddr, int infoSize);

/*
 * Can only operate against currently running 32 bit mach_kernel
 */
static int
output_kernel_symbols(struct proc *p)
{
    struct vnode		*vp;
    kauth_cred_t		cred = p->p_ucred;	/* XXX */
    struct vnode_attr		va;
    struct vfs_context		context;
    struct load_command		*cmd;
    struct mach_header		*orig_mh, *mh;
    struct segment_command	*orig_ds, *orig_ts, *orig_le, *sg;
    struct section		*se, *const_text;
    struct symtab_command	*st, *orig_st;
    struct nlist		*sym;
    vm_size_t			orig_mhsize, orig_st_size;
    vm_offset_t			header;
    vm_size_t			header_size = 0; /* out: protected by header */
    int				error, error1;
    unsigned int		i, j;
    caddr_t			addr;
    vm_offset_t			offset;
    int				rc_mh, rc_sc;

    error = EFAULT;

    vp		= NULL;
    header	= NULL;
    orig_mh	= NULL;
    orig_st	= NULL;
    
    // Dispose of unnecessary gumf, the booter doesn't need to load these
    rc_mh = IODTGetLoaderInfo("Kernel-__HEADER",
				(void **)&orig_mh, &orig_mhsize);
    if (rc_mh == 0 && orig_mh)
	IODTFreeLoaderInfo("Kernel-__HEADER",
			    (void *)orig_mh, round_page_32(orig_mhsize));

    rc_sc = IODTGetLoaderInfo("Kernel-__SYMTAB",
				(void **) &orig_st, &orig_st_size);
    if (rc_sc == 0 && orig_st)
	IODTFreeLoaderInfo("Kernel-__SYMTAB",
			    (void *)orig_st, round_page_32(orig_st_size));

    if (cred->cr_svuid != cred->cr_ruid || cred->cr_svgid != cred->cr_rgid)
	goto out;

    // Check to see if the root is 'e' or 'n', is this a test for network?
    if (rootdevice[0] == 'e' && rootdevice[1] == 'n')
	goto out;

    context.vc_proc = p;
    context.vc_ucred = cred;

    if ((error = vnode_open("mach.sym", (O_CREAT | FWRITE), (S_IRUSR | S_IRGRP | S_IROTH), 0, &vp, &context)))
        goto out;

    /* Don't dump to non-regular files or files with links. */
    error = EFAULT;
    VATTR_INIT(&va);
    VATTR_WANTED(&va, va_nlink);
    if ((vp->v_type != VREG) || vnode_getattr(vp, &va, &context) || (va.va_nlink != 1))
	goto out;

    VATTR_INIT(&va);			/* better to do it here than waste more stack in vnode_getsize */
    VATTR_SET(&va, va_data_size, 0);
    vnode_setattr(vp, &va, &context);
    p->p_acflag |= ACORE;

    // If the file type is MH_EXECUTE then this must be a kernel
    // as all Kernel extensions must be of type MH_OBJECT
    orig_ds = orig_ts = orig_le = NULL;
    orig_st = NULL;
    orig_mh = &_mh_execute_header;
    cmd = (struct load_command *) &orig_mh[1];
    for (i = 0; i < orig_mh->ncmds; i++) {
	if (cmd->cmd == LC_SEGMENT) {
	    struct segment_command *orig_sg = (struct segment_command *) cmd;
    
	    if (!strcmp(SEG_TEXT, orig_sg->segname))
		orig_ts = orig_sg;
	    else if (!strcmp(SEG_DATA, orig_sg->segname))
		orig_ds = orig_sg;
	    else if (!strcmp(SEG_LINKEDIT, orig_sg->segname))
		orig_le = orig_sg;
	}
	else if (cmd->cmd == LC_SYMTAB)
	    orig_st = (struct symtab_command *) cmd;
    
	cmd = (struct load_command *) ((caddr_t) cmd + cmd->cmdsize);
    }

    if (!orig_ts || !orig_ds || !orig_le || !orig_st) 
	goto out;

    const_text = NULL;
    se = (struct section *) &orig_ts[1];
    for (i = 0; i < orig_ts->nsects; i++, se++) {
	if (!strcmp("__const", se->sectname)) {
	    const_text = se;
	    break;
	}
    }
    if (!const_text)
	goto out;

    header_size =   sizeof(struct mach_header) 
		    + orig_ts->cmdsize
		    + orig_ds->cmdsize
		    + sizeof(struct symtab_command);

    (void) kmem_alloc(kernel_map,
			    (vm_offset_t *) &header,
			    (vm_size_t) header_size);
    if (header)
	bzero((void *) header, header_size);
    else
	goto out;

    /*
     *	Set up Mach-O header.
     */
    mh = (struct mach_header *) header;
    mh->magic      = orig_mh->magic;
    mh->cputype    = orig_mh->cputype;
    mh->cpusubtype = orig_mh->cpusubtype;
    mh->filetype   = orig_mh->filetype;
    mh->ncmds      = 3;
    mh->sizeofcmds = header_size - sizeof(struct mach_header);
    mh->flags      = orig_mh->flags;

    // Initialise the current file offset and addr
    offset = round_page(header_size);
    addr = (caddr_t) const_text->addr;	// Load address of __TEXT,__const

    /*
     * Construct a TEXT segment load command
     * the only part of the TEXT segment we keep is the __TEXT,__const
     * which contains the kernel vtables. 
     */
    sg = (struct segment_command *) &mh[1];
    bcopy(orig_ts, sg, orig_ts->cmdsize);
    sg->vmaddr   = (unsigned long) addr;
    sg->vmsize   = const_text->size;
    sg->fileoff  = 0;
    sg->filesize = const_text->size + round_page(header_size);
    sg->maxprot  = 0;
    sg->initprot = 0;
    sg->flags    = 0;
    se = (struct section *)(sg+1);
    for ( j = 0; j < sg->nsects; j++, se++ ) {
	se->addr  = (unsigned long) addr;
	se->size  = 0;
	se->offset = offset;
	se->nreloc = 0;
	if (!strcmp("__const", se->sectname)) {
	    se->size = const_text->size;
	    addr    += const_text->size;
	    offset  += const_text->size;
	    const_text = se;
	}
    }
    offset = round_page(offset);

    // Now copy of the __DATA segment load command, the image need
    // not be stored to disk nobody needs it, yet!
    sg = (struct segment_command *)((int)sg + sg->cmdsize);
    bcopy(orig_ds, sg, orig_ds->cmdsize);

    sg->vmaddr   = (unsigned long) addr;
    sg->vmsize   = 0x1000;	// One page for some reason?
    sg->fileoff  = offset;
    sg->filesize = 0;
    sg->maxprot  = 0;
    sg->initprot = 0;
    sg->flags    = 0;
    se = (struct section *)(sg+1);
    for ( j = 0; j < sg->nsects; j++, se++ ) {
	se->addr  = (unsigned long) addr;
	se->size  = 0;
	se->offset = offset;
	se->nreloc = 0;
    }
    offset = round_page(offset);


    /*
     *	Set up LC_SYMTAB command
     */
    st          = (struct symtab_command *)((int)sg + sg->cmdsize);
    st->cmd     = LC_SYMTAB;
    st->cmdsize = sizeof(struct symtab_command);
    st->symoff  = offset;
    st->nsyms   = orig_st->nsyms;
    st->strsize = orig_st->strsize;
    st->stroff =  offset + st->nsyms * sizeof(struct nlist);    

    /*
     * Convert the symbol table in place from section references
     * to absolute references.
     */
    sym = (struct nlist *) orig_le->vmaddr;
    for (i = 0; i < st->nsyms; i++, sym++ ) {
	if ( (sym->n_type & N_TYPE) == N_SECT) {
	    sym->n_sect = NO_SECT;
	    sym->n_type = (sym->n_type & ~N_TYPE) | N_ABS;
	}
    }

    /*
     *	Write out the load commands at the beginning of the file.
     */
    error = vn_rdwr(UIO_WRITE, vp, (caddr_t) mh, header_size, (off_t) 0,
		    UIO_SYSSPACE32, IO_NODELOCKED|IO_UNIT, cred, (int *) 0, p);
    if (error)
	goto out;

    /*
     *	Write out the __TEXT,__const data segment.
     */
    error = vn_rdwr(UIO_WRITE, vp, (caddr_t) const_text->addr,
		    const_text->size, const_text->offset,
		    UIO_SYSSPACE32, IO_NODELOCKED|IO_UNIT, cred, (int *) 0, p);
    if (error)
	goto out;

    /*
     * 	Write out kernel symbols
     */
    offset = st->nsyms * sizeof(struct nlist) + st->strsize;	// symtab size
    error = vn_rdwr(UIO_WRITE, vp,
		   (caddr_t) orig_le->vmaddr, offset, st->symoff,
		    UIO_SYSSPACE32, IO_NODELOCKED|IO_UNIT, cred, (int *) 0, p);
out:
    if (header)
	kmem_free(kernel_map, header, header_size);

    if (vp) {
	error1 = vnode_close(vp, FWRITE, &context);
	if (!error) error = error1;
    }

    return(error);
}
/*
 * 
 */
int get_kernel_symfile(struct proc *p, char **symfile)
{
    if (!kernel_symfile_opened) {
        kernel_symfile_opened = 1;
        error_code = output_kernel_symbols(p);
    }
    if (!error_code)
	*symfile = "\\mach.sym";

    return error_code;
}

struct kern_direct_file_io_ref_t
{
    struct vfs_context		context;
    struct vnode		*vp;
};


static int file_ioctl(void * p1, void * p2, int theIoctl, caddr_t result)
{
    dev_t device = (dev_t) p1;

    return ((*bdevsw[major(device)].d_ioctl)
		    (device, theIoctl, result, S_IFBLK, p2));
}

static int device_ioctl(void * p1, __unused void * p2, int theIoctl, caddr_t result)
{
    return (VNOP_IOCTL(p1, theIoctl, result, 0, p2));
}

struct kern_direct_file_io_ref_t *
kern_open_file_for_direct_io(const char * name, 
			     kern_get_file_extents_callback_t callback, 
			     void * callback_ref,
			     dev_t * device_result,
                             uint64_t * partitionbase_result,
                             uint64_t * maxiocount_result)
{
    struct kern_direct_file_io_ref_t * ref;

    struct proc 		*p;
    struct ucred 		*cred;
    struct vnode_attr		va;
    int				error;
    off_t			f_offset;
    uint32_t			blksize;
    uint64_t			size;
    dev_t			device;
    off_t 			maxiocount, count;

    int (*do_ioctl)(void * p1, void * p2, int theIoctl, caddr_t result);
    void * p1;
    void * p2;

    error = EFAULT;

    ref = (struct kern_direct_file_io_ref_t *) kalloc(sizeof(struct kern_direct_file_io_ref_t));
    if (!ref)
    {
	error = EFAULT;
    	goto out;
    }

    ref->vp = NULL;
    p = current_proc();		// kernproc;
    cred = p->p_ucred;
    ref->context.vc_proc = p;
    ref->context.vc_ucred = cred;

    if ((error = vnode_open(name, (O_CREAT | FWRITE), (0), 0, &ref->vp, &ref->context)))
        goto out;

    VATTR_INIT(&va);
    VATTR_WANTED(&va, va_rdev);
    VATTR_WANTED(&va, va_fsid);
    VATTR_WANTED(&va, va_data_size);
    VATTR_WANTED(&va, va_nlink);
    error = EFAULT;
    if (vnode_getattr(ref->vp, &va, &ref->context))
    	goto out;

    kprintf("vp va_rdev major %d minor %d\n", major(va.va_rdev), minor(va.va_rdev));
    kprintf("vp va_fsid major %d minor %d\n", major(va.va_fsid), minor(va.va_fsid));
    kprintf("vp size %qd\n", va.va_data_size);

    if (ref->vp->v_type == VREG)
    {
	/* Don't dump files with links. */
	if (va.va_nlink != 1)
	    goto out;

        device = va.va_fsid;
        p1 = (void *) device;
        p2 = p;
        do_ioctl = &file_ioctl;
    }
    else if ((ref->vp->v_type == VBLK) || (ref->vp->v_type == VCHR))
    {
	/* Partition. */
        device = va.va_rdev;

        p1 = ref->vp;
        p2 = &ref->context;
        do_ioctl = &device_ioctl;
    }
    else
    {
	/* Don't dump to non-regular files. */
	error = EFAULT;
        goto out;
    }

    // get partition base

    error = do_ioctl(p1, p2, DKIOCGETBASE, (caddr_t) partitionbase_result);
    if (error)
        goto out;

    // get block size & constraints

    error = do_ioctl(p1, p2, DKIOCGETBLOCKSIZE, (caddr_t) &blksize);
    if (error)
        goto out;

    maxiocount = 1*1024*1024*1024;

    error = do_ioctl(p1, p2, DKIOCGETMAXBLOCKCOUNTREAD, (caddr_t) &count);
    if (error)
        count = 0;
    count *= blksize;
    if (count && (count < maxiocount))
        maxiocount = count;

    error = do_ioctl(p1, p2, DKIOCGETMAXBLOCKCOUNTWRITE, (caddr_t) &count);
    if (error)
        count = 0;
    count *= blksize;
    if (count && (count < maxiocount))
        maxiocount = count;

    error = do_ioctl(p1, p2, DKIOCGETMAXBYTECOUNTREAD, (caddr_t) &count);
    if (error)
        count = 0;
    if (count && (count < maxiocount))
        maxiocount = count;

    error = do_ioctl(p1, p2, DKIOCGETMAXBYTECOUNTWRITE, (caddr_t) &count);
    if (error)
        count = 0;
    if (count && (count < maxiocount))
        maxiocount = count;

    error = do_ioctl(p1, p2, DKIOCGETMAXSEGMENTBYTECOUNTREAD, (caddr_t) &count);
    if (error)
        count = 0;
    if (count && (count < maxiocount))
        maxiocount = count;

    error = do_ioctl(p1, p2, DKIOCGETMAXSEGMENTBYTECOUNTWRITE, (caddr_t) &count);
    if (error)
        count = 0;
    if (count && (count < maxiocount))
        maxiocount = count;

    kprintf("max io 0x%qx bytes\n", maxiocount);
    if (maxiocount_result)
        *maxiocount_result = maxiocount;

    // generate the block list

    error = 0;
    if (ref->vp->v_type == VREG)
    {
	f_offset = 0;
	while(f_offset < (off_t) va.va_data_size) 
	{
	    size_t io_size = 1*1024*1024*1024;
	    daddr64_t blkno;

	    error = VNOP_BLOCKMAP(ref->vp, f_offset, io_size, &blkno, (size_t *)&io_size, NULL, 0, NULL);
	    if (error)
		goto out;
	    callback(callback_ref, ((uint64_t) blkno) * blksize, (uint64_t) io_size);
	    f_offset += io_size;
	}
	callback(callback_ref, 0ULL, 0ULL);
    }
    else if ((ref->vp->v_type == VBLK) || (ref->vp->v_type == VCHR))
    {
        error = do_ioctl(p1, p2, DKIOCGETBLOCKCOUNT, (caddr_t) &size);
        if (error)
            goto out;
	size *= blksize;
	callback(callback_ref, 0ULL, size);
	callback(callback_ref, size, 0ULL);
    }

    if (device_result)
        *device_result = device;

out:
    kprintf("kern_open_file_for_direct_io(%d)\n", error);

    if (error && ref) {
	if (ref->vp)
	    vnode_close(ref->vp, FWRITE, &ref->context);

	kfree(ref, sizeof(struct kern_direct_file_io_ref_t));
    }

    return(ref);
}

int
kern_write_file(struct kern_direct_file_io_ref_t * ref, off_t offset, caddr_t addr, vm_size_t len)
{
    return (vn_rdwr(UIO_WRITE, ref->vp,
			addr, len, offset,
			UIO_SYSSPACE32, IO_SYNC|IO_NODELOCKED|IO_UNIT, 
                        ref->context.vc_ucred, (int *) 0, ref->context.vc_proc));
}

void
kern_close_file_for_direct_io(struct kern_direct_file_io_ref_t * ref)
{
    kprintf("kern_close_file_for_direct_io\n");

    if (ref) {
	int                error;

	if (ref->vp) {
	    error = vnode_close(ref->vp, FWRITE, &ref->context);
	    kprintf("vnode_close(%d)\n", error);
	}
	kfree(ref, sizeof(struct kern_direct_file_io_ref_t));
    }
}