/*      $NetBSD: kern_ctf.c,v 1.12 2026/01/04 06:43:48 kre Exp $        */
/*-
 * Copyright (c) 2008 John Birrell <jb@freebsd.org>
 * All rights reserved.
 *
 * 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 AUTHOR 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 AUTHOR 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.
 *
 * $FreeBSD: src/sys/kern/kern_ctf.c,v 1.1.4.1 2009/08/03 08:13:06 kensmith Exp $
 */

#define _KSYMS_PRIVATE
#define ELFSIZE ARCH_ELFSIZE

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_ctf.c,v 1.12 2026/01/04 06:43:48 kre Exp $");

#include <sys/types.h>

#include <sys/exec.h>
#include <sys/exec_elf.h>
#include <sys/kern_ctf.h>
#include <sys/kmem.h>
#include <sys/kobj.h>
#include <sys/kobj_impl.h>
#include <sys/ksyms.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/sdt.h>

#include <net/zlib.h>

/*
 * Note this file is included by both link_elf.c and link_elf_obj.c.
 *
 * The CTF header structure definition can't be used here because it's
 * (annoyingly) covered by the CDDL. We will just use a few bytes from
 * it as an integer array where we 'know' what they mean.
 */
#define CTF_HDR_SIZE            36
#define CTF_HDR_STRTAB_U32      7
#define CTF_HDR_STRLEN_U32      8

static void *
z_alloc(void *nil, u_int items, u_int size)
{
        void *ptr;

        ptr = malloc(items * size, M_TEMP, M_NOWAIT);
        return ptr;
}

static void
z_free(void *nil, void *ptr)
{
        free(ptr, M_TEMP);
}

int
mod_ctf_get(struct module *mod, mod_ctf_t **mcp)
{
        mod_ctf_t *mc;
        struct ksyms_symtab *st;
        void * ctftab = NULL;
        size_t sz;
        int error = 0;
        int compressed = 0;

        void *ctfbuf = NULL;
        uint8_t *ctfaddr;
        uint16_t ctfmagic;
        size_t ctfsize;

        /*
         * Return the cached mc if there is one already.
         */

        extern specificdata_key_t fbt_module_key;

        mc = module_getspecific(mod, fbt_module_key);
        if (mc != NULL) {
                *mcp = mc;
                return (0);
        }

        /*
         * Allocate and initialize a new mc.
         */

        mc = kmem_zalloc(sizeof(mod_ctf_t), KM_SLEEP);
        st = ksyms_get_mod(module_name(mod));
        if (st != NULL) {
                mc->nmap     = st->sd_nmap;
                mc->nmapsize = st->sd_nmapsize;
        }

        if (mod->mod_kobj == NULL) {
                /* no kobj entry, try building from ksyms list */
                if (st == NULL) {
                        error = SET_ERROR(ENOENT);
                        goto out;
                }

                ctfaddr = st->sd_ctfstart;
                ctfsize = st->sd_ctfsize;

                mc->symtab = st->sd_symstart;
                mc->strtab = st->sd_strstart;
                mc->strcnt = 0;         /* XXX TBD */
                mc->nsym   = st->sd_symsize / sizeof(Elf_Sym);
        } else {
                if (kobj_find_section(mod->mod_kobj, ".SUNW_ctf", (void **)&ctfaddr, &ctfsize)) {
                        error = SET_ERROR(ENOENT);
                        goto out;
                }

                mc->symtab = mod->mod_kobj->ko_symtab;
                mc->strtab = mod->mod_kobj->ko_strtab;
                mc->strcnt = 0;         /* XXX TBD */
                mc->nsym   = mod->mod_kobj->ko_symcnt;
        }

        if (ctfaddr == NULL) {
                error = SET_ERROR(ENOENT);
                goto out;
        }

        /* Check the CTF magic number. */
        memcpy(&ctfmagic, ctfaddr, sizeof ctfmagic);
        if (ctfmagic != CTF_MAGIC) {
                error = SET_ERROR(EINVAL);
                goto out;
        }

        /* Check if version 2 or 3. */
        if (ctfaddr[2] != 2 && ctfaddr[2] != 3) {
                error = SET_ERROR(EINVAL);
                goto out;
        }

        /* Check if the data is compressed. */
        if ((ctfaddr[3] & 0x1) != 0) {
                uint32_t *u32 = (uint32_t *) ctfaddr;

                /*
                 * The last two fields in the CTF header are the offset
                 * from the end of the header to the start of the string
                 * data and the length of that string data. se this
                 * information to determine the decompressed CTF data
                 * buffer required.
                 */
                sz = u32[CTF_HDR_STRTAB_U32] + u32[CTF_HDR_STRLEN_U32] +
                    CTF_HDR_SIZE;

                compressed = 1;
        } else {
                /*
                 * The CTF data is not compressed, so the ELF section
                 * size is the same as the buffer size required.
                 */
                sz = ctfsize;
        }

        /*
         * Allocate memory to buffer the CTF data in its decompressed
         * form.
         */
        if (compressed) {
                if ((ctfbuf = malloc(sz, M_TEMP, M_WAITOK)) == NULL) {
                        error = SET_ERROR(ENOMEM);
                        goto out;
                }
                ctftab = ctfbuf;
                mc->ctfalloc = 1;
        } else {
                ctftab = (void *)ctfaddr;
        }

        /* Check if decompression is required. */
        if (compressed) {
                z_stream zs;
                int ret;

                /*
                 * The header isn't compressed, so copy that into the
                 * CTF buffer first.
                 */
                memcpy(ctftab, ctfaddr, CTF_HDR_SIZE);

                /* Initialise the zlib structure. */
                memset(&zs, 0, sizeof(zs));
                zs.zalloc = z_alloc;
                zs.zfree = z_free;

                if (inflateInit2(&zs, MAX_WBITS) != Z_OK) {
                        error = SET_ERROR(EIO);
                        goto out;
                }

                zs.avail_in = ctfsize - CTF_HDR_SIZE;
                zs.next_in = ctfaddr + CTF_HDR_SIZE;
                zs.avail_out = sz - CTF_HDR_SIZE;
                zs.next_out = ((uint8_t *) ctftab) + CTF_HDR_SIZE;
                inflateReset(&zs);
                if ((ret = inflate(&zs, Z_FINISH)) != Z_STREAM_END) {
                        printf("%s(%d): zlib inflate returned %d\n", __func__, __LINE__, ret);
                        error = SET_ERROR(EIO);
                        goto out;
                }
        }

        /* Got the CTF data! */
        mc->ctfcnt = ctfsize;
        mc->ctftab = ctftab;
        ctfbuf = NULL;

        module_setspecific(mod, fbt_module_key, mc);
        *mcp = mc;
        mc = NULL;

out:
        if (ctfbuf != NULL)
                free(ctfbuf, M_TEMP);
        if (mc != NULL)
                kmem_free(mc, sizeof(*mc));

        return (error);
}