/*      $NetBSD: firmload.c,v 1.24 2022/10/26 23:39:10 riastradh Exp $  */

/*-
* Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: firmload.c,v 1.24 2022/10/26 23:39:10 riastradh Exp $");

/*
* The firmload API provides an interface for device drivers to access
* firmware images that must be loaded onto their devices.
*/

#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/filedesc.h>
#include <sys/kmem.h>
#include <sys/namei.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/kauth.h>
#include <sys/lwp.h>

#include <dev/firmload.h>

struct firmware_handle {
       struct vnode    *fh_vp;
       off_t            fh_size;
};

static firmware_handle_t
firmware_handle_alloc(void)
{

       return (kmem_alloc(sizeof(struct firmware_handle), KM_SLEEP));
}

static void
firmware_handle_free(firmware_handle_t fh)
{

       kmem_free(fh, sizeof(*fh));
}

#if !defined(FIRMWARE_PATHS)
#define FIRMWARE_PATHS          \
       "/libdata/firmware:/usr/libdata/firmware:/usr/pkg/libdata/firmware:/usr/pkg/libdata"
#endif

static char firmware_paths[PATH_MAX+1] = FIRMWARE_PATHS;

static int
sysctl_hw_firmware_path(SYSCTLFN_ARGS)
{
       int error, i;
       char newpath[PATH_MAX+1];
       struct sysctlnode node;
       char expected_char;

       node = *rnode;
       node.sysctl_data = &newpath[0];
       memcpy(node.sysctl_data, rnode->sysctl_data, PATH_MAX+1);
       error = sysctl_lookup(SYSCTLFN_CALL(&node));
       if (error || newp == NULL)
               return (error);

       /*
        * Make sure that all of the paths in the new path list are
        * absolute.
        *
        * When sysctl_lookup() deals with a string, it's guaranteed
        * to come back nul-terminated.
        */
       expected_char = '/';
       for (i = 0; i < PATH_MAX+1; i++) {
               if (expected_char != 0 && newpath[i] != expected_char)
                       return (EINVAL);
               if (newpath[i] == '\0')
                       break;
               else if (newpath[i] == ':')
                       expected_char = '/';
               else
                       expected_char = 0;
       }

       memcpy(rnode->sysctl_data, node.sysctl_data, PATH_MAX+1);

       return (0);
}

SYSCTL_SETUP(sysctl_hw_firmware_setup, "sysctl hw.firmware subtree setup")
{
       const struct sysctlnode *firmware_node;

       if (sysctl_createv(clog, 0, NULL, &firmware_node,
           CTLFLAG_PERMANENT,
           CTLTYPE_NODE, "firmware", NULL,
           NULL, 0, NULL, 0,
           CTL_HW, CTL_CREATE, CTL_EOL) != 0)
               return;

       sysctl_createv(clog, 0, NULL, NULL,
           CTLFLAG_READWRITE,
           CTLTYPE_STRING, "path",
           SYSCTL_DESCR("Device firmware loading path list"),
           sysctl_hw_firmware_path, 0, firmware_paths, PATH_MAX+1,
           CTL_HW, firmware_node->sysctl_num, CTL_CREATE, CTL_EOL);
}

static char *
firmware_path_next(const char *drvname, const char *imgname, char *pnbuf,
   char **prefixp)
{
       char *prefix = *prefixp;
       size_t maxprefix, i;

       if (prefix == NULL              /* terminated early */
           || *prefix != '/') {        /* empty or not absolute */
               *prefixp = NULL;
               return (NULL);
       }

       /*
        * Compute the max path prefix based on the length of the provided
        * names.
        */
       maxprefix = MAXPATHLEN -
               (1 /* / */
                + strlen(drvname)
                + 1 /* / */
                + strlen(imgname)
                + 1 /* terminating NUL */);

       /* Check for underflow (size_t is unsigned). */
       if (maxprefix > MAXPATHLEN) {
               *prefixp = NULL;
               return (NULL);
       }

       for (i = 0; i < maxprefix; i++) {
               if (*prefix == ':' || *prefix == '\0')
                       break;
               pnbuf[i] = *prefix++;
       }

       if (*prefix != ':' && *prefix != '\0') {
               /* Path prefix was too long. */
               *prefixp = NULL;
               return (NULL);
       }

       if (*prefix != '\0')
               prefix++;
       *prefixp = prefix;

       KASSERT(MAXPATHLEN >= i);
       snprintf(pnbuf + i, MAXPATHLEN - i, "/%s/%s", drvname, imgname);

       return (pnbuf);
}

static char *
firmware_path_first(const char *drvname, const char *imgname, char *pnbuf,
   char **prefixp)
{

       *prefixp = firmware_paths;
       return (firmware_path_next(drvname, imgname, pnbuf, prefixp));
}

/*
* firmware_open:
*
*      Open a firmware image and return its handle.
*/
int
firmware_open(const char *drvname, const char *imgname, firmware_handle_t *fhp)
{
       struct pathbuf *pb;
       struct vattr va;
       char *pnbuf, *path, *prefix;
       firmware_handle_t fh;
       struct vnode *vp;
       int error;

       if (drvname == NULL || imgname == NULL)
               return (EINVAL);

       if (cwdi0.cwdi_cdir == NULL) {
               printf("firmware_open(%s/%s) called too early.\n",
                       drvname, imgname);
               return ENOENT;
       }

       pnbuf = PNBUF_GET();
       KASSERT(pnbuf != NULL);

       fh = firmware_handle_alloc();
       KASSERT(fh != NULL);

       error = 0;
       for (path = firmware_path_first(drvname, imgname, pnbuf, &prefix);
            path != NULL;
            path = firmware_path_next(drvname, imgname, pnbuf, &prefix)) {
               pb = pathbuf_create(path);
               if (pb == NULL) {
                       error = ENOMEM;
                       break;
               }
               error = vn_open(NULL, pb, NOCHROOT, FREAD, 0, &vp, NULL, NULL);
               pathbuf_destroy(pb);
               if (error == ENOENT) {
                       continue;
               }
               break;
       }

       PNBUF_PUT(pnbuf);
       if (error) {
               firmware_handle_free(fh);
               return (error);
       }

       error = VOP_GETATTR(vp, &va, kauth_cred_get());
       if (error) {
               VOP_UNLOCK(vp);
               (void)vn_close(vp, FREAD, kauth_cred_get());
               firmware_handle_free(fh);
               return (error);
       }

       if (va.va_type != VREG) {
               VOP_UNLOCK(vp);
               (void)vn_close(vp, FREAD, kauth_cred_get());
               firmware_handle_free(fh);
               return (EINVAL);
       }

       /* XXX Mark as busy text file. */

       fh->fh_vp = vp;
       fh->fh_size = va.va_size;

       VOP_UNLOCK(vp);

       *fhp = fh;
       return (0);
}

/*
* firmware_close:
*
*      Close a firmware image.
*/
int
firmware_close(firmware_handle_t fh)
{
       int error;

       error = vn_close(fh->fh_vp, FREAD, kauth_cred_get());
       firmware_handle_free(fh);
       return (error);
}

/*
* firmware_get_size:
*
*      Return the total size of a firmware image.
*/
off_t
firmware_get_size(firmware_handle_t fh)
{

       return (fh->fh_size);
}

/*
* firmware_read:
*
*      Read data from a firmware image at the specified offset into
*      the provided buffer.
*/
int
firmware_read(firmware_handle_t fh, off_t offset, void *buf, size_t len)
{

       return (vn_rdwr(UIO_READ, fh->fh_vp, buf, len, offset,
                       UIO_SYSSPACE, 0, kauth_cred_get(), NULL, curlwp));
}

/*
* firmware_malloc:
*
*      Allocate a firmware buffer of the specified size.
*
*      NOTE: This routine may block.
*/
void *
firmware_malloc(size_t size)
{

       return (kmem_alloc(size, KM_SLEEP));
}

/*
* firmware_free:
*
*      Free a previously allocated firmware buffer.
*/
/*ARGSUSED*/
void
firmware_free(void *v, size_t size)
{

       kmem_free(v, size);
}

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