/* Capstone Disassembly Engine */

/* BPF Backend by david942j <david942j@gmail.com>, 2019 */

/* SPDX-FileCopyrightText: 2024 Roee Toledano <roeetoledano10@gmail.com> */

/* SPDX-License-Identifier: BSD-3 */

#include <string.h>

#include "BPFConstants.h"

#include "BPFMapping.h"

#include "../../Mapping.h"

#include "../../utils.h"

#ifndef CAPSTONE_DIET

static const name_map group_name_maps[] = {

  { BPF_GRP_INVALID, NULL },

  { BPF_GRP_LOAD, "load" },  { BPF_GRP_STORE, "store" },

  { BPF_GRP_ALU, "alu" },    { BPF_GRP_JUMP, "jump" },

  { BPF_GRP_CALL, "call" },  { BPF_GRP_RETURN, "return" },

  { BPF_GRP_MISC, "misc" },

};

#endif

const char *BPF_group_name(csh handle, unsigned int id)

{

#ifndef CAPSTONE_DIET

  return id2name(group_name_maps, ARR_SIZE(group_name_maps), id);

#else

  return NULL;

#endif

}

#ifndef CAPSTONE_DIET

static const name_map insn_name_maps[BPF_INS_ENDING] = {

  { BPF_INS_INVALID, NULL },

  { BPF_INS_ADD, "add" },   { BPF_INS_SUB, "sub" },

  { BPF_INS_MUL, "mul" },   { BPF_INS_DIV, "div" },

  { BPF_INS_SDIV, "sdiv" }, { BPF_INS_OR, "or" },

  { BPF_INS_AND, "and" },   { BPF_INS_LSH, "lsh" },

  { BPF_INS_RSH, "rsh" },   { BPF_INS_NEG, "neg" },

  { BPF_INS_MOD, "mod" },   { BPF_INS_SMOD, "smod" },

  { BPF_INS_XOR, "xor" },   { BPF_INS_MOV, "mov" },

  { BPF_INS_MOVSB, "movsb" }, { BPF_INS_MOVSH, "movsh" },

  { BPF_INS_ARSH, "arsh" },

  { BPF_INS_ADD64, "add64" }, { BPF_INS_SUB64, "sub64" },

  { BPF_INS_MUL64, "mul64" }, { BPF_INS_DIV64, "div64" },

  { BPF_INS_SDIV64, "sdiv64" }, { BPF_INS_OR64, "or64" },

  { BPF_INS_AND64, "and64" }, { BPF_INS_LSH64, "lsh64" },

  { BPF_INS_RSH64, "rsh64" }, { BPF_INS_NEG64, "neg64" },

  { BPF_INS_MOD64, "mod64" }, { BPF_INS_SMOD64, "smod64" },

  { BPF_INS_XOR64, "xor64" }, { BPF_INS_MOV64, "mov64" },

  { BPF_INS_MOVSB64, "movsb64" }, { BPF_INS_MOVSH64, "movsh64" },

  { BPF_INS_MOVSW64, "movsw64" }, { BPF_INS_ARSH64, "arsh64" },

  { BPF_INS_LE16, "le16" }, { BPF_INS_LE32, "le32" },

  { BPF_INS_LE64, "le64" }, { BPF_INS_BE16, "be16" },

  { BPF_INS_BE32, "be32" }, { BPF_INS_BE64, "be64" },

  { BPF_INS_BSWAP16, "bswap16" }, { BPF_INS_BSWAP32, "bswap32" },

  { BPF_INS_BSWAP64, "bswap64" },

  { BPF_INS_LDW, "ldw" },   { BPF_INS_LDH, "ldh" },

  { BPF_INS_LDB, "ldb" },   { BPF_INS_LDDW, "lddw" },

  { BPF_INS_LDXW, "ldxw" }, { BPF_INS_LDXH, "ldxh" },

  { BPF_INS_LDXB, "ldxb" }, { BPF_INS_LDXDW, "ldxdw" },

  { BPF_INS_LDABSW, "ldabsw" }, { BPF_INS_LDABSH, "ldabsh" },

  { BPF_INS_LDABSB, "ldabsb" }, { BPF_INS_LDINDW, "ldindw" },

  { BPF_INS_LDINDH, "ldindh" }, { BPF_INS_LDINDB, "ldindb" },

  { BPF_INS_STW, "stw" },   { BPF_INS_STH, "sth" },

  { BPF_INS_STB, "stb" },   { BPF_INS_STDW, "stdw" },

  { BPF_INS_STXW, "stxw" }, { BPF_INS_STXH, "stxh" },

  { BPF_INS_STXB, "stxb" }, { BPF_INS_STXDW, "stxdw" },

  { BPF_INS_XADDW, "xaddw" }, { BPF_INS_XADDDW, "xadddw" },

  { BPF_INS_JA, "ja" },   { BPF_INS_JEQ, "jeq" },

  { BPF_INS_JGT, "jgt" },   { BPF_INS_JGE, "jge" },

  { BPF_INS_JSET, "jset" }, { BPF_INS_JNE, "jne" },

  { BPF_INS_JSGT, "jsgt" }, { BPF_INS_JSGE, "jsge" },

  { BPF_INS_CALL, "call" }, { BPF_INS_CALLX, "callx" },

  { BPF_INS_EXIT, "exit" }, { BPF_INS_JLT, "jlt" },

  { BPF_INS_JLE, "jle" },   { BPF_INS_JSLT, "jslt" },

  { BPF_INS_JSLE, "jsle" },

  { BPF_INS_JAL, "jal" },   { BPF_INS_JEQ32, "jeq32" },

  { BPF_INS_JGT32, "jgt32" }, { BPF_INS_JGE32, "jge32" },

  { BPF_INS_JSET32, "jset32" }, { BPF_INS_JNE32, "jne32" },

  { BPF_INS_JSGT32, "jsgt32" }, { BPF_INS_JSGE32, "jsge32" },

  { BPF_INS_JLT32, "jlt32" }, { BPF_INS_JLE32, "jle32" },

  { BPF_INS_JSLT32, "jslt32" }, { BPF_INS_JSLE32, "jsle32" },

  { BPF_INS_RET, "ret" },

  { BPF_INS_AADD, "aadd" }, { BPF_INS_AOR, "aor" },

  { BPF_INS_AAND, "aand" }, { BPF_INS_AXOR, "axor" },

  { BPF_INS_AFADD, "afadd" }, { BPF_INS_AFOR, "afor" },

  { BPF_INS_AFAND, "afand" }, { BPF_INS_AFXOR, "afxor" },

  { BPF_INS_AXCHG64, "axchg64" }, { BPF_INS_ACMPXCHG64, "acmpxchg64" },

  { BPF_INS_AADD64, "aadd64" }, { BPF_INS_AOR64, "aor64" },

  { BPF_INS_AAND64, "aand64" }, { BPF_INS_AXOR64, "axor64" },

  { BPF_INS_AFADD64, "afadd64" }, { BPF_INS_AFOR64, "afor64" },

  { BPF_INS_AFAND64, "afand64" }, { BPF_INS_AFXOR64, "afxor64" },

  { BPF_INS_TAX, "tax" },   { BPF_INS_TXA, "txa" },

};

#endif

bool BPF_getFeature(const cs_mode mode, const cs_mode feature)

{

  return (mode & feature);

}

const char *BPF_insn_name(csh handle, unsigned int id)

{

#ifndef CAPSTONE_DIET

  /* We have some special cases because 'ld' in cBPF is equivalent to 'ldw'

   * in eBPF, and we don't want to see 'ldw' appears in cBPF mode.

   */

  if (!EBPF_MODE(((cs_struct *)handle)->mode)) {

    switch (id) {

    case BPF_INS_LD:

      return "ld";

    case BPF_INS_LDX:

      return "ldx";

    case BPF_INS_ST:

      return "st";

    case BPF_INS_STX:

      return "stx";

    }

  }

  return id2name(insn_name_maps, ARR_SIZE(insn_name_maps), id);

#else

  return NULL;

#endif

}

const char *BPF_reg_name(csh handle, unsigned int reg)

{

#ifndef CAPSTONE_DIET

  if (EBPF_MODE(((cs_struct *)handle)->mode)) {

    if (reg < BPF_REG_R0 || reg > BPF_REG_R10)

      return NULL;

    static const char reg_names[11][4] = { "r0", "r1", "r2", "r3",

                   "r4", "r5", "r6", "r7",

                   "r8", "r9", "r10" };

    return reg_names[reg - BPF_REG_R0];

  }

  /* cBPF mode */

  if (reg == BPF_REG_A)

    return "a";

  else if (reg == BPF_REG_X)

    return "x";

  else

    return NULL;

#else

  return NULL;

#endif

}

void BPF_get_insn_id(cs_struct *h, cs_insn *insn, unsigned int id)

{

  // Not used by BPF. Information is set after disassembly.

}

static void sort_and_uniq(cs_regs arr, uint8_t n, uint8_t *new_n)

{

  /* arr is always a tiny (usually n < 3) array,

   * a simple O(n^2) sort is efficient enough. */

  size_t iMin;

  size_t tmp;

  /* a modified selection sort for sorting and making unique */

  for (size_t j = 0; j < n; j++) {

    /* arr[iMin] will be min(arr[j .. n-1]) */

    iMin = j;

    for (size_t i = j + 1; i < n; i++) {

      if (arr[i] < arr[iMin])

        iMin = i;

    }

    if (j != 0 && arr[iMin] == arr[j - 1]) { // duplicate ele found

      arr[iMin] = arr[n - 1];

      --n;

    } else {

      tmp = arr[iMin];

      arr[iMin] = arr[j];

      arr[j] = tmp;

    }

  }

  *new_n = n;

}

void BPF_reg_access(const cs_insn *insn, cs_regs regs_read,

        uint8_t *regs_read_count, cs_regs regs_write,

        uint8_t *regs_write_count)

{

  unsigned i;

  uint8_t read_count, write_count;

  const cs_bpf *bpf = &(insn->detail->bpf);

  read_count = insn->detail->regs_read_count;

  write_count = insn->detail->regs_write_count;

  // implicit registers

  memcpy(regs_read, insn->detail->regs_read,

         read_count * sizeof(insn->detail->regs_read[0]));

  memcpy(regs_write, insn->detail->regs_write,

         write_count * sizeof(insn->detail->regs_write[0]));

  for (i = 0; i < bpf->op_count; i++) {

    const cs_bpf_op *op = &(bpf->operands[i]);

    switch (op->type) {

    default:

      break;

    case BPF_OP_REG:

      if (op->access & CS_AC_READ) {

        regs_read[read_count] = op->reg;

        read_count++;

      }

      if (op->access & CS_AC_WRITE) {

        regs_write[write_count] = op->reg;

        write_count++;

      }

      break;

    case BPF_OP_MEM:

      if (op->mem.base != BPF_REG_INVALID) {

        regs_read[read_count] = op->mem.base;

        read_count++;

      }

      break;

    }

  }

  sort_and_uniq(regs_read, read_count, regs_read_count);

  sort_and_uniq(regs_write, write_count, regs_write_count);

}