fdt_ro.c

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// 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_nodename_eq_(const void *fdt, int offset,
                const char *s, int len)
{
    int olen;
    const char *p = fdt_get_name(fdt, offset, &olen);
 
    if (!p || olen < len)
        /* short match */
        return 0;
 
    if (memcmp(p, s, len) != 0)
        return 0;
 
    if (p[len] == '\0')
        return 1;
    else if (!memchr(s, '@', len) && (p[len] == '@'))
        return 1;
    else
        return 0;
}
 
const char *fdt_get_string(const void *fdt, int stroffset, int *lenp)
{
    int32_t totalsize;
    uint32_t absoffset;
    size_t len;
    int err;
    const char *s, *n;
 
    if (can_assume(VALID_INPUT)) {
        s = (const char *)fdt + fdt_off_dt_strings(fdt) + stroffset;
 
        if (lenp)
            *lenp = strlen(s);
        return s;
    }
    totalsize = fdt_ro_probe_(fdt);
    err = totalsize;
    if (totalsize < 0)
        goto fail;
 
    err = -FDT_ERR_BADOFFSET;
    absoffset = stroffset + fdt_off_dt_strings(fdt);
    if (absoffset >= (unsigned)totalsize)
        goto fail;
    len = totalsize - absoffset;
 
    if (fdt_magic(fdt) == FDT_MAGIC) {
        if (stroffset < 0)
            goto fail;
        if (can_assume(LATEST) || fdt_version(fdt) >= 17) {
            if ((unsigned)stroffset >= fdt_size_dt_strings(fdt))
                goto fail;
            if ((fdt_size_dt_strings(fdt) - stroffset) < len)
                len = fdt_size_dt_strings(fdt) - stroffset;
        }
    } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
        unsigned int sw_stroffset = -stroffset;
 
        if ((stroffset >= 0) ||
            (sw_stroffset > fdt_size_dt_strings(fdt)))
            goto fail;
        if (sw_stroffset < len)
            len = sw_stroffset;
    } else {
        err = -FDT_ERR_INTERNAL;
        goto fail;
    }
 
    s = (const char *)fdt + absoffset;
    n = memchr(s, '\0', len);
    if (!n) {
        /* missing terminating NULL */
        err = -FDT_ERR_TRUNCATED;
        goto fail;
    }
 
    if (lenp)
        *lenp = n - s;
    return s;
 
fail:
    if (lenp)
        *lenp = err;
    return NULL;
}
 
const char *fdt_string(const void *fdt, int stroffset)
{
    return fdt_get_string(fdt, stroffset, NULL);
}
 
static int fdt_string_eq_(const void *fdt, int stroffset,
              const char *s, int len)
{
    int slen;
    const char *p = fdt_get_string(fdt, stroffset, &slen);
 
    return p && (slen == len) && (memcmp(p, s, len) == 0);
}
 
int fdt_find_max_phandle(const void *fdt, uint32_t *phandle)
{
    uint32_t max = 0;
    int offset = -1;
 
    while (true) {
        uint32_t value;
 
        offset = fdt_next_node(fdt, offset, NULL);
        if (offset < 0) {
            if (offset == -FDT_ERR_NOTFOUND)
                break;
 
            return offset;
        }
 
        value = fdt_get_phandle(fdt, offset);
 
        if (value > max)
            max = value;
    }
 
    if (phandle)
        *phandle = max;
 
    return 0;
}
 
int fdt_generate_phandle(const void *fdt, uint32_t *phandle)
{
    uint32_t max;
    int err;
 
    err = fdt_find_max_phandle(fdt, &max);
    if (err < 0)
        return err;
 
    if (max == FDT_MAX_PHANDLE)
        return -FDT_ERR_NOPHANDLES;
 
    if (phandle)
        *phandle = max + 1;
 
    return 0;
}
 
static const struct fdt_reserve_entry *fdt_mem_rsv(const void *fdt, int n)
{
    unsigned int offset = n * sizeof(struct fdt_reserve_entry);
    unsigned int absoffset = fdt_off_mem_rsvmap(fdt) + offset;
 
    if (!can_assume(VALID_INPUT)) {
        if (absoffset < fdt_off_mem_rsvmap(fdt))
            return NULL;
        if (absoffset > fdt_totalsize(fdt) -
            sizeof(struct fdt_reserve_entry))
            return NULL;
    }
    return fdt_mem_rsv_(fdt, n);
}
 
int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
{
    const struct fdt_reserve_entry *re;
 
    FDT_RO_PROBE(fdt);
    re = fdt_mem_rsv(fdt, n);
    if (!can_assume(VALID_INPUT) && !re)
        return -FDT_ERR_BADOFFSET;
 
    *address = fdt64_ld_(&re->address);
    *size = fdt64_ld_(&re->size);
    return 0;
}
 
int fdt_num_mem_rsv(const void *fdt)
{
    int i;
    const struct fdt_reserve_entry *re;
 
    for (i = 0; (re = fdt_mem_rsv(fdt, i)) != NULL; i++) {
        if (fdt64_ld_(&re->size) == 0)
            return i;
    }
    return -FDT_ERR_TRUNCATED;
}
 
static int nextprop_(const void *fdt, int offset)
{
    uint32_t tag;
    int nextoffset;
 
    do {
        tag = fdt_next_tag(fdt, offset, &nextoffset);
 
        switch (tag) {
        case FDT_END:
            if (nextoffset >= 0)
                return -FDT_ERR_BADSTRUCTURE;
            else
                return nextoffset;
 
        case FDT_PROP:
            return offset;
        }
        offset = nextoffset;
    } while (tag == FDT_NOP);
 
    return -FDT_ERR_NOTFOUND;
}
 
int fdt_subnode_offset_namelen(const void *fdt, int offset,
                   const char *name, int namelen)
{
    int depth;
 
    FDT_RO_PROBE(fdt);
 
    for (depth = 0;
         (offset >= 0) && (depth >= 0);
         offset = fdt_next_node(fdt, offset, &depth))
        if ((depth == 1)
            && fdt_nodename_eq_(fdt, offset, name, namelen))
            return offset;
 
    if (depth < 0)
        return -FDT_ERR_NOTFOUND;
    return offset; /* error */
}
 
int fdt_subnode_offset(const void *fdt, int parentoffset,
               const char *name)
{
    return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name));
}
 
int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen)
{
    const char *end = path + namelen;
    const char *p = path;
    int offset = 0;
 
    FDT_RO_PROBE(fdt);
 
    /* see if we have an alias */
    if (*path != '/') {
        const char *q = memchr(path, '/', end - p);
 
        if (!q)
            q = end;
 
        p = fdt_get_alias_namelen(fdt, p, q - p);
        if (!p)
            return -FDT_ERR_BADPATH;
        offset = fdt_path_offset(fdt, p);
 
        p = q;
    }
 
    while (p < end) {
        const char *q;
 
        while (*p == '/') {
            p++;
            if (p == end)
                return offset;
        }
        q = memchr(p, '/', end - p);
        if (! q)
            q = end;
 
        offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p);
        if (offset < 0)
            return offset;
 
        p = q;
    }
 
    return offset;
}
 
int fdt_path_offset(const void *fdt, const char *path)
{
    return fdt_path_offset_namelen(fdt, path, strlen(path));
}
 
const char *fdt_get_name(const void *fdt, int nodeoffset, int *len)
{
    const struct fdt_node_header *nh = fdt_offset_ptr_(fdt, nodeoffset);
    const char *nameptr;
    int err;
 
    if (((err = fdt_ro_probe_(fdt)) < 0)
        || ((err = fdt_check_node_offset_(fdt, nodeoffset)) < 0))
            goto fail;
 
    nameptr = nh->name;
 
    if (!can_assume(LATEST) && fdt_version(fdt) < 0x10) {
        /*
         * For old FDT versions, match the naming conventions of V16:
         * give only the leaf name (after all /). The actual tree
         * contents are loosely checked.
         */
        const char *leaf;
        leaf = strrchr(nameptr, '/');
        if (leaf == NULL) {
            err = -FDT_ERR_BADSTRUCTURE;
            goto fail;
        }
        nameptr = leaf+1;
    }
 
    if (len)
        *len = strlen(nameptr);
 
    return nameptr;
 
 fail:
    if (len)
        *len = err;
    return NULL;
}
 
int fdt_first_property_offset(const void *fdt, int nodeoffset)
{
    int offset;
 
    if ((offset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
        return offset;
 
    return nextprop_(fdt, offset);
}
 
int fdt_next_property_offset(const void *fdt, int offset)
{
    if ((offset = fdt_check_prop_offset_(fdt, offset)) < 0)
        return offset;
 
    return nextprop_(fdt, offset);
}
 
static const struct fdt_property *fdt_get_property_by_offset_(const void *fdt,
                                      int offset,
                                      int *lenp)
{
    int err;
    const struct fdt_property *prop;
 
    if (!can_assume(VALID_INPUT) &&
        (err = fdt_check_prop_offset_(fdt, offset)) < 0) {
        if (lenp)
            *lenp = err;
        return NULL;
    }
 
    prop = fdt_offset_ptr_(fdt, offset);
 
    if (lenp)
        *lenp = fdt32_ld_(&prop->len);
 
    return prop;
}
 
const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
                              int offset,
                              int *lenp)
{
    /* Prior to version 16, properties may need realignment
     * and this API does not work. fdt_getprop_*() will, however. */
 
    if (!can_assume(LATEST) && fdt_version(fdt) < 0x10) {
        if (lenp)
            *lenp = -FDT_ERR_BADVERSION;
        return NULL;
    }
 
    return fdt_get_property_by_offset_(fdt, offset, lenp);
}
 
static const struct fdt_property *fdt_get_property_namelen_(const void *fdt,
                                    int offset,
                                    const char *name,
                                    int namelen,
                                int *lenp,
                                int *poffset)
{
    for (offset = fdt_first_property_offset(fdt, offset);
         (offset >= 0);
         (offset = fdt_next_property_offset(fdt, offset))) {
        const struct fdt_property *prop;
 
        prop = fdt_get_property_by_offset_(fdt, offset, lenp);
        if (!can_assume(LIBFDT_FLAWLESS) && !prop) {
            offset = -FDT_ERR_INTERNAL;
            break;
        }
        if (fdt_string_eq_(fdt, fdt32_ld_(&prop->nameoff),
                   name, namelen)) {
            if (poffset)
                *poffset = offset;
            return prop;
        }
    }
 
    if (lenp)
        *lenp = offset;
    return NULL;
}
 
 
const struct fdt_property *fdt_get_property_namelen(const void *fdt,
                            int offset,
                            const char *name,
                            int namelen, int *lenp)
{
    /* Prior to version 16, properties may need realignment
     * and this API does not work. fdt_getprop_*() will, however. */
    if (!can_assume(LATEST) && fdt_version(fdt) < 0x10) {
        if (lenp)
            *lenp = -FDT_ERR_BADVERSION;
        return NULL;
    }
 
    return fdt_get_property_namelen_(fdt, offset, name, namelen, lenp,
                     NULL);
}
 
 
const struct fdt_property *fdt_get_property(const void *fdt,
                        int nodeoffset,
                        const char *name, int *lenp)
{
    return fdt_get_property_namelen(fdt, nodeoffset, name,
                    strlen(name), lenp);
}
 
const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
                const char *name, int namelen, int *lenp)
{
    int poffset;
    const struct fdt_property *prop;
 
    prop = fdt_get_property_namelen_(fdt, nodeoffset, name, namelen, lenp,
                     &poffset);
    if (!prop)
        return NULL;
 
    /* Handle realignment */
    if (!can_assume(LATEST) && fdt_version(fdt) < 0x10 &&
        (poffset + sizeof(*prop)) % 8 && fdt32_ld_(&prop->len) >= 8)
        return prop->data + 4;
    return prop->data;
}
 
const void *fdt_getprop_by_offset(const void *fdt, int offset,
                  const char **namep, int *lenp)
{
    const struct fdt_property *prop;
 
    prop = fdt_get_property_by_offset_(fdt, offset, lenp);
    if (!prop)
        return NULL;
    if (namep) {
        const char *name;
        int namelen;
 
        if (!can_assume(VALID_INPUT)) {
            name = fdt_get_string(fdt, fdt32_ld_(&prop->nameoff),
                          &namelen);
            *namep = name;
            if (!name) {
                if (lenp)
                    *lenp = namelen;
                return NULL;
            }
        } else {
            *namep = fdt_string(fdt, fdt32_ld_(&prop->nameoff));
        }
    }
 
    /* Handle realignment */
    if (!can_assume(LATEST) && fdt_version(fdt) < 0x10 &&
        (offset + sizeof(*prop)) % 8 && fdt32_ld_(&prop->len) >= 8)
        return prop->data + 4;
    return prop->data;
}
 
const void *fdt_getprop(const void *fdt, int nodeoffset,
            const char *name, int *lenp)
{
    return fdt_getprop_namelen(fdt, nodeoffset, name, strlen(name), lenp);
}
 
uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
{
    const fdt32_t *php;
    int len;
 
    /* FIXME: This is a bit sub-optimal, since we potentially scan
     * over all the properties twice. */
    php = fdt_getprop(fdt, nodeoffset, "phandle", &len);
    if (!php || (len != sizeof(*php))) {
        php = fdt_getprop(fdt, nodeoffset, "linux,phandle", &len);
        if (!php || (len != sizeof(*php)))
            return 0;
    }
 
    return fdt32_ld_(php);
}
 
const char *fdt_get_alias_namelen(const void *fdt,
                  const char *name, int namelen)
{
    int aliasoffset;
 
    aliasoffset = fdt_path_offset(fdt, "/aliases");
    if (aliasoffset < 0)
        return NULL;
 
    return fdt_getprop_namelen(fdt, aliasoffset, name, namelen, NULL);
}
 
const char *fdt_get_alias(const void *fdt, const char *name)
{
    return fdt_get_alias_namelen(fdt, name, strlen(name));
}
 
int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
{
    int pdepth = 0, p = 0;
    int offset, depth, namelen;
    const char *name;
 
    FDT_RO_PROBE(fdt);
 
    if (buflen < 2)
        return -FDT_ERR_NOSPACE;
 
    for (offset = 0, depth = 0;
         (offset >= 0) && (offset <= nodeoffset);
         offset = fdt_next_node(fdt, offset, &depth)) {
        while (pdepth > depth) {
            do {
                p--;
            } while (buf[p-1] != '/');
            pdepth--;
        }
 
        if (pdepth >= depth) {
            name = fdt_get_name(fdt, offset, &namelen);
            if (!name)
                return namelen;
            if ((p + namelen + 1) <= buflen) {
                memcpy(buf + p, name, namelen);
                p += namelen;
                buf[p++] = '/';
                pdepth++;
            }
        }
 
        if (offset == nodeoffset) {
            if (pdepth < (depth + 1))
                return -FDT_ERR_NOSPACE;
 
            if (p > 1) /* special case so that root path is "/", not "" */
                p--;
            buf[p] = '\0';
            return 0;
        }
    }
 
    if ((offset == -FDT_ERR_NOTFOUND) || (offset >= 0))
        return -FDT_ERR_BADOFFSET;
    else if (offset == -FDT_ERR_BADOFFSET)
        return -FDT_ERR_BADSTRUCTURE;
 
    return offset; /* error from fdt_next_node() */
}
 
int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
                 int supernodedepth, int *nodedepth)
{
    int offset, depth;
    int supernodeoffset = -FDT_ERR_INTERNAL;
 
    FDT_RO_PROBE(fdt);
 
    if (supernodedepth < 0)
        return -FDT_ERR_NOTFOUND;
 
    for (offset = 0, depth = 0;
         (offset >= 0) && (offset <= nodeoffset);
         offset = fdt_next_node(fdt, offset, &depth)) {
        if (depth == supernodedepth)
            supernodeoffset = offset;
 
        if (offset == nodeoffset) {
            if (nodedepth)
                *nodedepth = depth;
 
            if (supernodedepth > depth)
                return -FDT_ERR_NOTFOUND;
            else
                return supernodeoffset;
        }
    }
 
    if (!can_assume(VALID_INPUT)) {
        if ((offset == -FDT_ERR_NOTFOUND) || (offset >= 0))
            return -FDT_ERR_BADOFFSET;
        else if (offset == -FDT_ERR_BADOFFSET)
            return -FDT_ERR_BADSTRUCTURE;
    }
 
    return offset; /* error from fdt_next_node() */
}
 
int fdt_node_depth(const void *fdt, int nodeoffset)
{
    int nodedepth;
    int err;
 
    err = fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, &nodedepth);
    if (err)
        return (can_assume(LIBFDT_FLAWLESS) || err < 0) ? err :
            -FDT_ERR_INTERNAL;
    return nodedepth;
}
 
int fdt_parent_offset(const void *fdt, int nodeoffset)
{
    int nodedepth = fdt_node_depth(fdt, nodeoffset);
 
    if (nodedepth < 0)
        return nodedepth;
    return fdt_supernode_atdepth_offset(fdt, nodeoffset,
                        nodedepth - 1, NULL);
}
 
int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
                  const char *propname,
                  const void *propval, int proplen)
{
    int offset;
    const void *val;
    int len;
 
    FDT_RO_PROBE(fdt);
 
    /* FIXME: The algorithm here is pretty horrible: we scan each
     * property of a node in fdt_getprop(), then if that didn't
     * find what we want, we scan over them again making our way
     * to the next node.  Still it's the easiest to implement
     * approach; performance can come later. */
    for (offset = fdt_next_node(fdt, startoffset, NULL);
         offset >= 0;
         offset = fdt_next_node(fdt, offset, NULL)) {
        val = fdt_getprop(fdt, offset, propname, &len);
        if (val && (len == proplen)
            && (memcmp(val, propval, len) == 0))
            return offset;
    }
 
    return offset; /* error from fdt_next_node() */
}
 
int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle)
{
    int offset;
 
    if ((phandle == 0) || (phandle == ~0U))
        return -FDT_ERR_BADPHANDLE;
 
    FDT_RO_PROBE(fdt);
 
    /* FIXME: The algorithm here is pretty horrible: we
     * potentially scan each property of a node in
     * fdt_get_phandle(), then if that didn't find what
     * we want, we scan over them again making our way to the next
     * node.  Still it's the easiest to implement approach;
     * performance can come later. */
    for (offset = fdt_next_node(fdt, -1, NULL);
         offset >= 0;
         offset = fdt_next_node(fdt, offset, NULL)) {
        if (fdt_get_phandle(fdt, offset) == phandle)
            return offset;
    }
 
    return offset; /* error from fdt_next_node() */
}
 
int fdt_stringlist_contains(const char *strlist, int listlen, const char *str)
{
    int len = strlen(str);
    const char *p;
 
    while (listlen >= len) {
        if (memcmp(str, strlist, len+1) == 0)
            return 1;
        p = memchr(strlist, '\0', listlen);
        if (!p)
            return 0; /* malformed strlist.. */
        listlen -= (p-strlist) + 1;
        strlist = p + 1;
    }
    return 0;
}
 
int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property)
{
    const char *list, *end;
    int length, count = 0;
 
    list = fdt_getprop(fdt, nodeoffset, property, &length);
    if (!list)
        return length;
 
    end = list + length;
 
    while (list < end) {
        length = strnlen(list, end - list) + 1;
 
        /* Abort if the last string isn't properly NUL-terminated. */
        if (list + length > end)
            return -FDT_ERR_BADVALUE;
 
        list += length;
        count++;
    }
 
    return count;
}
 
int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
              const char *string)
{
    int length, len, idx = 0;
    const char *list, *end;
 
    list = fdt_getprop(fdt, nodeoffset, property, &length);
    if (!list)
        return length;
 
    len = strlen(string) + 1;
    end = list + length;
 
    while (list < end) {
        length = strnlen(list, end - list) + 1;
 
        /* Abort if the last string isn't properly NUL-terminated. */
        if (list + length > end)
            return -FDT_ERR_BADVALUE;
 
        if (length == len && memcmp(list, string, length) == 0)
            return idx;
 
        list += length;
        idx++;
    }
 
    return -FDT_ERR_NOTFOUND;
}
 
const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
                   const char *property, int idx,
                   int *lenp)
{
    const char *list, *end;
    int length;
 
    list = fdt_getprop(fdt, nodeoffset, property, &length);
    if (!list) {
        if (lenp)
            *lenp = length;
 
        return NULL;
    }
 
    end = list + length;
 
    while (list < end) {
        length = strnlen(list, end - list) + 1;
 
        /* Abort if the last string isn't properly NUL-terminated. */
        if (list + length > end) {
            if (lenp)
                *lenp = -FDT_ERR_BADVALUE;
 
            return NULL;
        }
 
        if (idx == 0) {
            if (lenp)
                *lenp = length - 1;
 
            return list;
        }
 
        list += length;
        idx--;
    }
 
    if (lenp)
        *lenp = -FDT_ERR_NOTFOUND;
 
    return NULL;
}
 
int fdt_node_check_compatible(const void *fdt, int nodeoffset,
                  const char *compatible)
{
    const void *prop;
    int len;
 
    prop = fdt_getprop(fdt, nodeoffset, "compatible", &len);
    if (!prop)
        return len;
 
    return !fdt_stringlist_contains(prop, len, compatible);
}
 
int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
                  const char *compatible)
{
    int offset, err;
 
    FDT_RO_PROBE(fdt);
 
    /* FIXME: The algorithm here is pretty horrible: we scan each
     * property of a node in fdt_node_check_compatible(), then if
     * that didn't find what we want, we scan over them again
     * making our way to the next node.  Still it's the easiest to
     * implement approach; performance can come later. */
    for (offset = fdt_next_node(fdt, startoffset, NULL);
         offset >= 0;
         offset = fdt_next_node(fdt, offset, NULL)) {
        err = fdt_node_check_compatible(fdt, offset, compatible);
        if ((err < 0) && (err != -FDT_ERR_NOTFOUND))
            return err;
        else if (err == 0)
            return offset;
    }
 
    return offset; /* error from fdt_next_node() */
}