// 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_sw_probe_(void *fdt)
{
        if (!can_assume(VALID_INPUT)) {
                if (fdt_magic(fdt) == FDT_MAGIC)
                        return -FDT_ERR_BADSTATE;
                else if (fdt_magic(fdt) != FDT_SW_MAGIC)
                        return -FDT_ERR_BADMAGIC;
        }

        return 0;
}

#define FDT_SW_PROBE(fdt) \
        { \
                int err; \
                if ((err = fdt_sw_probe_(fdt)) != 0) \
                        return err; \
        }

/* 'memrsv' state:      Initial state after fdt_create()
 *
 * Allowed functions:
 *      fdt_add_reservemap_entry()
 *      fdt_finish_reservemap()         [moves to 'struct' state]
 */
static int fdt_sw_probe_memrsv_(void *fdt)
{
        int err = fdt_sw_probe_(fdt);
        if (err)
                return err;

        if (!can_assume(VALID_INPUT) && fdt_off_dt_strings(fdt) != 0)
                return -FDT_ERR_BADSTATE;
        return 0;
}

#define FDT_SW_PROBE_MEMRSV(fdt) \
        { \
                int err; \
                if ((err = fdt_sw_probe_memrsv_(fdt)) != 0) \
                        return err; \
        }

/* 'struct' state:      Enter this state after fdt_finish_reservemap()
 *
 * Allowed functions:
 *      fdt_begin_node()
 *      fdt_end_node()
 *      fdt_property*()
 *      fdt_finish()                    [moves to 'complete' state]
 */
static int fdt_sw_probe_struct_(void *fdt)
{
        int err = fdt_sw_probe_(fdt);
        if (err)
                return err;

        if (!can_assume(VALID_INPUT) &&
            fdt_off_dt_strings(fdt) != fdt_totalsize(fdt))
                return -FDT_ERR_BADSTATE;
        return 0;
}

#define FDT_SW_PROBE_STRUCT(fdt) \
        { \
                int err; \
                if ((err = fdt_sw_probe_struct_(fdt)) != 0) \
                        return err; \
        }

static inline uint32_t sw_flags(void *fdt)
{
        /* assert: (fdt_magic(fdt) == FDT_SW_MAGIC) */
        return fdt_last_comp_version(fdt);
}

/* 'complete' state:    Enter this state after fdt_finish()
 *
 * Allowed functions: none
 */

static void *fdt_grab_space_(void *fdt, size_t len)
{
        unsigned int offset = fdt_size_dt_struct(fdt);
        unsigned int spaceleft;

        spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt)
                - fdt_size_dt_strings(fdt);

        if ((offset + len < offset) || (offset + len > spaceleft))
                return NULL;

        fdt_set_size_dt_struct(fdt, offset + len);
        return fdt_offset_ptr_w_(fdt, offset);
}

int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags)
{
        const int hdrsize = FDT_ALIGN(sizeof(struct fdt_header),
                                      sizeof(struct fdt_reserve_entry));
        void *fdt = buf;

        if (bufsize < hdrsize)
                return -FDT_ERR_NOSPACE;

        if (flags & ~FDT_CREATE_FLAGS_ALL)
                return -FDT_ERR_BADFLAGS;

        memset(buf, 0, bufsize);

        /*
         * magic and last_comp_version keep intermediate state during the fdt
         * creation process, which is replaced with the proper FDT format by
         * fdt_finish().
         *
         * flags should be accessed with sw_flags().
         */
        fdt_set_magic(fdt, FDT_SW_MAGIC);
        fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
        fdt_set_last_comp_version(fdt, flags);

        fdt_set_totalsize(fdt,  bufsize);

        fdt_set_off_mem_rsvmap(fdt, hdrsize);
        fdt_set_off_dt_struct(fdt, fdt_off_mem_rsvmap(fdt));
        fdt_set_off_dt_strings(fdt, 0);

        return 0;
}

int fdt_create(void *buf, int bufsize)
{
        return fdt_create_with_flags(buf, bufsize, 0);
}

int fdt_resize(void *fdt, void *buf, int bufsize)
{
        size_t headsize, tailsize;
        char *oldtail, *newtail;

        FDT_SW_PROBE(fdt);

        if (bufsize < 0)
                return -FDT_ERR_NOSPACE;

        headsize = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
        tailsize = fdt_size_dt_strings(fdt);

        if (!can_assume(VALID_DTB) &&
            headsize + tailsize > fdt_totalsize(fdt))
                return -FDT_ERR_INTERNAL;

        if ((headsize + tailsize) > (unsigned)bufsize)
                return -FDT_ERR_NOSPACE;

        oldtail = (char *)fdt + fdt_totalsize(fdt) - tailsize;
        newtail = (char *)buf + bufsize - tailsize;

        /* Two cases to avoid clobbering data if the old and new
         * buffers partially overlap */
        if (buf <= fdt) {
                memmove(buf, fdt, headsize);
                memmove(newtail, oldtail, tailsize);
        } else {
                memmove(newtail, oldtail, tailsize);
                memmove(buf, fdt, headsize);
        }

        fdt_set_totalsize(buf, bufsize);
        if (fdt_off_dt_strings(buf))
                fdt_set_off_dt_strings(buf, bufsize);

        return 0;
}

int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size)
{
        struct fdt_reserve_entry *re;
        int offset;

        FDT_SW_PROBE_MEMRSV(fdt);

        offset = fdt_off_dt_struct(fdt);
        if ((offset + sizeof(*re)) > fdt_totalsize(fdt))
                return -FDT_ERR_NOSPACE;

        re = (struct fdt_reserve_entry *)((char *)fdt + offset);
        re->address = cpu_to_fdt64(addr);
        re->size = cpu_to_fdt64(size);

        fdt_set_off_dt_struct(fdt, offset + sizeof(*re));

        return 0;
}

int fdt_finish_reservemap(void *fdt)
{
        int err = fdt_add_reservemap_entry(fdt, 0, 0);

        if (err)
                return err;

        fdt_set_off_dt_strings(fdt, fdt_totalsize(fdt));
        return 0;
}

int fdt_begin_node(void *fdt, const char *name)
{
        struct fdt_node_header *nh;
        int namelen;

        FDT_SW_PROBE_STRUCT(fdt);

        namelen = strlen(name) + 1;
        nh = fdt_grab_space_(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen));
        if (! nh)
                return -FDT_ERR_NOSPACE;

        nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
        memcpy(nh->name, name, namelen);
        return 0;
}

int fdt_end_node(void *fdt)
{
        fdt32_t *en;

        FDT_SW_PROBE_STRUCT(fdt);

        en = fdt_grab_space_(fdt, FDT_TAGSIZE);
        if (! en)
                return -FDT_ERR_NOSPACE;

        *en = cpu_to_fdt32(FDT_END_NODE);
        return 0;
}

static int fdt_add_string_(void *fdt, const char *s)
{
        char *strtab = (char *)fdt + fdt_totalsize(fdt);
        unsigned int strtabsize = fdt_size_dt_strings(fdt);
        unsigned int len = strlen(s) + 1;
        unsigned int struct_top, offset;

        offset = strtabsize + len;
        struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
        if (fdt_totalsize(fdt) - offset < struct_top)
                return 0; /* no more room :( */

        memcpy(strtab - offset, s, len);
        fdt_set_size_dt_strings(fdt, strtabsize + len);
        return -offset;
}

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

        fdt_set_size_dt_strings(fdt, strtabsize - len);
}

static int fdt_find_add_string_(void *fdt, const char *s, int *allocated)
{
        char *strtab = (char *)fdt + fdt_totalsize(fdt);
        int strtabsize = fdt_size_dt_strings(fdt);
        const char *p;

        *allocated = 0;

        p = fdt_find_string_(strtab - strtabsize, strtabsize, s);
        if (p)
                return p - strtab;

        *allocated = 1;

        return fdt_add_string_(fdt, s);
}

int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp)
{
        struct fdt_property *prop;
        int nameoff;
        int allocated;

        FDT_SW_PROBE_STRUCT(fdt);

        /* String de-duplication can be slow, _NO_NAME_DEDUP skips it */
        if (sw_flags(fdt) & FDT_CREATE_FLAG_NO_NAME_DEDUP) {
                allocated = 1;
                nameoff = fdt_add_string_(fdt, name);
        } else {
                nameoff = fdt_find_add_string_(fdt, name, &allocated);
        }
        if (nameoff == 0)
                return -FDT_ERR_NOSPACE;

        prop = fdt_grab_space_(fdt, sizeof(*prop) + FDT_TAGALIGN(len));
        if (! prop) {
                if (allocated)
                        fdt_del_last_string_(fdt, name);
                return -FDT_ERR_NOSPACE;
        }

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

int fdt_property(void *fdt, const char *name, const void *val, int len)
{
        void *ptr;
        int ret;

        ret = fdt_property_placeholder(fdt, name, len, &ptr);
        if (ret)
                return ret;
        memcpy(ptr, val, len);
        return 0;
}

int fdt_finish(void *fdt)
{
        char *p = (char *)fdt;
        fdt32_t *end;
        int oldstroffset, newstroffset;
        uint32_t tag;
        int offset, nextoffset;

        FDT_SW_PROBE_STRUCT(fdt);

        /* Add terminator */
        end = fdt_grab_space_(fdt, sizeof(*end));
        if (! end)
                return -FDT_ERR_NOSPACE;
        *end = cpu_to_fdt32(FDT_END);

        /* Relocate the string table */
        oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt);
        newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
        memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt));
        fdt_set_off_dt_strings(fdt, newstroffset);

        /* Walk the structure, correcting string offsets */
        offset = 0;
        while ((tag = fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) {
                if (tag == FDT_PROP) {
                        struct fdt_property *prop =
                                fdt_offset_ptr_w_(fdt, offset);
                        int nameoff;

                        nameoff = fdt32_to_cpu(prop->nameoff);
                        nameoff += fdt_size_dt_strings(fdt);
                        prop->nameoff = cpu_to_fdt32(nameoff);
                }
                offset = nextoffset;
        }
        if (nextoffset < 0)
                return nextoffset;

        /* Finally, adjust the header */
        fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt));

        /* And fix up fields that were keeping intermediate state. */
        fdt_set_last_comp_version(fdt, FDT_LAST_COMPATIBLE_VERSION);
        fdt_set_magic(fdt, FDT_MAGIC);

        return 0;
}