ofw/libfdt/fdt_rw.c

// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
/*
 * libfdt - Flat Device Tree manipulation
 * Copyright (C) 2006 David Gibson, IBM Corporation.
 */
#include "libfdt_env.h"

#include <fdt.h>
#include <libfdt.h>

#include "libfdt_internal.h"

static int fdt_blocks_misordered_(const void *fdt,
                  int mem_rsv_size, int struct_size)
{
    return (fdt_off_mem_rsvmap(fdt) < FDT_ALIGN(sizeof(struct fdt_header), 8))
        || (fdt_off_dt_struct(fdt) <
            (fdt_off_mem_rsvmap(fdt) + mem_rsv_size))
        || (fdt_off_dt_strings(fdt) <
            (fdt_off_dt_struct(fdt) + struct_size))
        || (fdt_totalsize(fdt) <
            (fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt)));
}

static int fdt_rw_probe_(void *fdt)
{
    if (can_assume(VALID_DTB))
        return 0;
    FDT_RO_PROBE(fdt);

    if (!can_assume(LATEST) && fdt_version(fdt) < 17)
        return -FDT_ERR_BADVERSION;
    if (fdt_blocks_misordered_(fdt, sizeof(struct fdt_reserve_entry),
                   fdt_size_dt_struct(fdt)))
        return -FDT_ERR_BADLAYOUT;
    if (!can_assume(LATEST) && fdt_version(fdt) > 17)
        fdt_set_version(fdt, 17);

    return 0;
}

#define FDT_RW_PROBE(fdt) \
    { \
        int err_; \
        if ((err_ = fdt_rw_probe_(fdt)) != 0) \
            return err_; \
    }

static inline unsigned int fdt_data_size_(void *fdt)
{
    return fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt);
}

static int fdt_splice_(void *fdt, void *splicepoint, int oldlen, int newlen)
{
    char *p = splicepoint;
    unsigned int dsize = fdt_data_size_(fdt);
    size_t soff = p - (char *)fdt;

    if ((oldlen < 0) || (soff + oldlen < soff) || (soff + oldlen > dsize))
        return -FDT_ERR_BADOFFSET;
    if ((p < (char *)fdt) || (dsize + newlen < (unsigned)oldlen))
        return -FDT_ERR_BADOFFSET;
    if (dsize - oldlen + newlen > fdt_totalsize(fdt))
        return -FDT_ERR_NOSPACE;
    memmove(p + newlen, p + oldlen, ((char *)fdt + dsize) - (p + oldlen));
    return 0;
}

static int fdt_splice_mem_rsv_(void *fdt, struct fdt_reserve_entry *p,
                   int oldn, int newn)
{
    int delta = (newn - oldn) * sizeof(*p);
    int err;
    err = fdt_splice_(fdt, p, oldn * sizeof(*p), newn * sizeof(*p));
    if (err)
        return err;
    fdt_set_off_dt_struct(fdt, fdt_off_dt_struct(fdt) + delta);
    fdt_set_off_dt_strings(fdt, fdt_off_dt_strings(fdt) + delta);
    return 0;
}

static int fdt_splice_struct_(void *fdt, void *p,
                  int oldlen, int newlen)
{
    int delta = newlen - oldlen;
    int err;

    if ((err = fdt_splice_(fdt, p, oldlen, newlen)))
        return err;

    fdt_set_size_dt_struct(fdt, fdt_size_dt_struct(fdt) + delta);
    fdt_set_off_dt_strings(fdt, fdt_off_dt_strings(fdt) + delta);
    return 0;
}

/* Must only be used to roll back in case of error */
static void fdt_del_last_string_(void *fdt, const char *s)
{
    int newlen = strlen(s) + 1;

    fdt_set_size_dt_strings(fdt, fdt_size_dt_strings(fdt) - newlen);
}

static int fdt_splice_string_(void *fdt, int newlen)
{
    void *p = (char *)fdt
        + fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt);
    int err;

    if ((err = fdt_splice_(fdt, p, 0, newlen)))
        return err;

    fdt_set_size_dt_strings(fdt, fdt_size_dt_strings(fdt) + newlen);
    return 0;
}

/**
 * fdt_find_add_string_() - Find or allocate a string
 *
 * @fdt: pointer to the device tree to check/adjust
 * @s: string to find/add
 * @allocated: Set to 0 if the string was found, 1 if not found and so
 *  allocated. Ignored if can_assume(NO_ROLLBACK)
 * @return offset of string in the string table (whether found or added)
 */
static int fdt_find_add_string_(void *fdt, const char *s, int *allocated)
{
    char *strtab = (char *)fdt + fdt_off_dt_strings(fdt);
    const char *p;
    char *new;
    int len = strlen(s) + 1;
    int err;

    if (!can_assume(NO_ROLLBACK))
        *allocated = 0;

    p = fdt_find_string_(strtab, fdt_size_dt_strings(fdt), s);
    if (p)
        /* found it */
        return (p - strtab);

    new = strtab + fdt_size_dt_strings(fdt);
    err = fdt_splice_string_(fdt, len);
    if (err)
        return err;

    if (!can_assume(NO_ROLLBACK))
        *allocated = 1;

    memcpy(new, s, len);
    return (new - strtab);
}

int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size)
{
    struct fdt_reserve_entry *re;
    int err;

    FDT_RW_PROBE(fdt);

    re = fdt_mem_rsv_w_(fdt, fdt_num_mem_rsv(fdt));
    err = fdt_splice_mem_rsv_(fdt, re, 0, 1);
    if (err)
        return err;

    re->address = cpu_to_fdt64(address);
    re->size = cpu_to_fdt64(size);
    return 0;
}

int fdt_del_mem_rsv(void *fdt, int n)
{
    struct fdt_reserve_entry *re = fdt_mem_rsv_w_(fdt, n);

    FDT_RW_PROBE(fdt);

    if (n >= fdt_num_mem_rsv(fdt))
        return -FDT_ERR_NOTFOUND;

    return fdt_splice_mem_rsv_(fdt, re, 1, 0);
}

static int fdt_resize_property_(void *fdt, int nodeoffset, const char *name,
                int len, struct fdt_property **prop)
{
    int oldlen;
    int err;

    *prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
    if (!*prop)
        return oldlen;

    if ((err = fdt_splice_struct_(fdt, (*prop)->data, FDT_TAGALIGN(oldlen),
                      FDT_TAGALIGN(len))))
        return err;

    (*prop)->len = cpu_to_fdt32(len);
    return 0;
}

static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
                 int len, struct fdt_property **prop)
{
    int proplen;
    int nextoffset;
    int namestroff;
    int err;
    int allocated;

    if ((nextoffset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
        return nextoffset;

    namestroff = fdt_find_add_string_(fdt, name, &allocated);
    if (namestroff < 0)
        return namestroff;

    *prop = fdt_offset_ptr_w_(fdt, nextoffset);
    proplen = sizeof(**prop) + FDT_TAGALIGN(len);

    err = fdt_splice_struct_(fdt, *prop, 0, proplen);
    if (err) {
        /* Delete the string if we failed to add it */
        if (!can_assume(NO_ROLLBACK) && allocated)
            fdt_del_last_string_(fdt, name);
        return err;
    }

    (*prop)->tag = cpu_to_fdt32(FDT_PROP);
    (*prop)->nameoff = cpu_to_fdt32(namestroff);
    (*prop)->len = cpu_to_fdt32(len);
    return 0;
}

int fdt_set_name(void *fdt, int nodeoffset, const char *name)
{
    char *namep;
    int oldlen, newlen;
    int err;

    FDT_RW_PROBE(fdt);

    namep = (char *)(uintptr_t)fdt_get_name(fdt, nodeoffset, &oldlen);
    if (!namep)
        return oldlen;

    newlen = strlen(name);

    err = fdt_splice_struct_(fdt, namep, FDT_TAGALIGN(oldlen+1),
                 FDT_TAGALIGN(newlen+1));
    if (err)
        return err;

    memcpy(namep, name, newlen+1);
    return 0;
}

int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
                int len, void **prop_data)
{
    struct fdt_property *prop;
    int err;

    FDT_RW_PROBE(fdt);

    err = fdt_resize_property_(fdt, nodeoffset, name, len, &prop);
    if (err == -FDT_ERR_NOTFOUND)
        err = fdt_add_property_(fdt, nodeoffset, name, len, &prop);
    if (err)
        return err;

    *prop_data = prop->data;
    return 0;
}

int fdt_setprop(void *fdt, int nodeoffset, const char *name,
        const void *val, int len)
{
    void *prop_data;
    int err;

    err = fdt_setprop_placeholder(fdt, nodeoffset, name, len, &prop_data);
    if (err)
        return err;

    if (len)
        memcpy(prop_data, val, len);
    return 0;
}

int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
           const void *val, int len)
{
    struct fdt_property *prop;
    int err, oldlen, newlen;

    FDT_RW_PROBE(fdt);

    prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
    if (prop) {
        newlen = len + oldlen;
        err = fdt_splice_struct_(fdt, prop->data,
                     FDT_TAGALIGN(oldlen),
                     FDT_TAGALIGN(newlen));
        if (err)
            return err;
        prop->len = cpu_to_fdt32(newlen);
        memcpy(prop->data + oldlen, val, len);
    } else {
        err = fdt_add_property_(fdt, nodeoffset, name, len, &prop);
        if (err)
            return err;
        memcpy(prop->data, val, len);
    }
    return 0;
}

int fdt_delprop(void *fdt, int nodeoffset, const char *name)
{
    struct fdt_property *prop;
    int len, proplen;

    FDT_RW_PROBE(fdt);

    prop = fdt_get_property_w(fdt, nodeoffset, name, &len);
    if (!prop)
        return len;

    proplen = sizeof(*prop) + FDT_TAGALIGN(len);
    return fdt_splice_struct_(fdt, prop, proplen, 0);
}

int fdt_add_subnode_namelen(void *fdt, int parentoffset,
                const char *name, int namelen)
{
    struct fdt_node_header *nh;
    int offset, nextoffset;
    int nodelen;
    int err;
    uint32_t tag;
    fdt32_t *endtag;

    FDT_RW_PROBE(fdt);

    offset = fdt_subnode_offset_namelen(fdt, parentoffset, name, namelen);
    if (offset >= 0)
        return -FDT_ERR_EXISTS;
    else if (offset != -FDT_ERR_NOTFOUND)
        return offset;

    /* Try to place the new node after the parent's properties */
    tag = fdt_next_tag(fdt, parentoffset, &nextoffset);
    /* the fdt_subnode_offset_namelen() should ensure this never hits */
    if (!can_assume(LIBFDT_FLAWLESS) && (tag != FDT_BEGIN_NODE))
        return -FDT_ERR_INTERNAL;
    do {
        offset = nextoffset;
        tag = fdt_next_tag(fdt, offset, &nextoffset);
    } while ((tag == FDT_PROP) || (tag == FDT_NOP));

    nh = fdt_offset_ptr_w_(fdt, offset);
    nodelen = sizeof(*nh) + FDT_TAGALIGN(namelen+1) + FDT_TAGSIZE;

    err = fdt_splice_struct_(fdt, nh, 0, nodelen);
    if (err)
        return err;

    nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
    memset(nh->name, 0, FDT_TAGALIGN(namelen+1));
    memcpy(nh->name, name, namelen);
    endtag = (fdt32_t *)((char *)nh + nodelen - FDT_TAGSIZE);
    *endtag = cpu_to_fdt32(FDT_END_NODE);

    return offset;
}

int fdt_add_subnode(void *fdt, int parentoffset, const char *name)
{
    return fdt_add_subnode_namelen(fdt, parentoffset, name, strlen(name));
}

int fdt_del_node(void *fdt, int nodeoffset)
{
    int endoffset;

    FDT_RW_PROBE(fdt);

    endoffset = fdt_node_end_offset_(fdt, nodeoffset);
    if (endoffset < 0)
        return endoffset;

    return fdt_splice_struct_(fdt, fdt_offset_ptr_w_(fdt, nodeoffset),
                  endoffset - nodeoffset, 0);
}

static void fdt_packblocks_(const char *old, char *new,
                int mem_rsv_size,
                int struct_size,
                int strings_size)
{
    int mem_rsv_off, struct_off, strings_off;

    mem_rsv_off = FDT_ALIGN(sizeof(struct fdt_header), 8);
    struct_off = mem_rsv_off + mem_rsv_size;
    strings_off = struct_off + struct_size;

    memmove(new + mem_rsv_off, old + fdt_off_mem_rsvmap(old), mem_rsv_size);
    fdt_set_off_mem_rsvmap(new, mem_rsv_off);

    memmove(new + struct_off, old + fdt_off_dt_struct(old), struct_size);
    fdt_set_off_dt_struct(new, struct_off);
    fdt_set_size_dt_struct(new, struct_size);

    memmove(new + strings_off, old + fdt_off_dt_strings(old), strings_size);
    fdt_set_off_dt_strings(new, strings_off);
    fdt_set_size_dt_strings(new, fdt_size_dt_strings(old));
}

int fdt_open_into(const void *fdt, void *buf, int bufsize)
{
    int err;
    int mem_rsv_size, struct_size;
    int newsize;
    const char *fdtstart = fdt;
    const char *fdtend = fdtstart + fdt_totalsize(fdt);
    char *tmp;

    FDT_RO_PROBE(fdt);

    mem_rsv_size = (fdt_num_mem_rsv(fdt)+1)
        * sizeof(struct fdt_reserve_entry);

    if (can_assume(LATEST) || fdt_version(fdt) >= 17) {
        struct_size = fdt_size_dt_struct(fdt);
    } else if (fdt_version(fdt) == 16) {
        struct_size = 0;
        while (fdt_next_tag(fdt, struct_size, &struct_size) != FDT_END)
            ;
        if (struct_size < 0)
            return struct_size;
    } else {
        return -FDT_ERR_BADVERSION;
    }

    if (can_assume(LIBFDT_ORDER) ||
        !fdt_blocks_misordered_(fdt, mem_rsv_size, struct_size)) {
        /* no further work necessary */
        err = fdt_move(fdt, buf, bufsize);
        if (err)
            return err;
        fdt_set_version(buf, 17);
        fdt_set_size_dt_struct(buf, struct_size);
        fdt_set_totalsize(buf, bufsize);
        return 0;
    }

    /* Need to reorder */
    newsize = FDT_ALIGN(sizeof(struct fdt_header), 8) + mem_rsv_size
        + struct_size + fdt_size_dt_strings(fdt);

    if (bufsize < newsize)
        return -FDT_ERR_NOSPACE;

    /* First attempt to build converted tree at beginning of buffer */
    tmp = buf;
    /* But if that overlaps with the old tree... */
    if (((tmp + newsize) > fdtstart) && (tmp < fdtend)) {
        /* Try right after the old tree instead */
        tmp = (char *)(uintptr_t)fdtend;
        if ((tmp + newsize) > ((char *)buf + bufsize))
            return -FDT_ERR_NOSPACE;
    }

    fdt_packblocks_(fdt, tmp, mem_rsv_size, struct_size,
            fdt_size_dt_strings(fdt));
    memmove(buf, tmp, newsize);

    fdt_set_magic(buf, FDT_MAGIC);
    fdt_set_totalsize(buf, bufsize);
    fdt_set_version(buf, 17);
    fdt_set_last_comp_version(buf, 16);
    fdt_set_boot_cpuid_phys(buf, fdt_boot_cpuid_phys(fdt));

    return 0;
}

int fdt_pack(void *fdt)
{
    int mem_rsv_size;

    FDT_RW_PROBE(fdt);

    mem_rsv_size = (fdt_num_mem_rsv(fdt)+1)
        * sizeof(struct fdt_reserve_entry);
    fdt_packblocks_(fdt, fdt, mem_rsv_size, fdt_size_dt_struct(fdt),
            fdt_size_dt_strings(fdt));
    fdt_set_totalsize(fdt, fdt_data_size_(fdt));

    return 0;
}