src/common/bytecode/bytecode.c

   1 /*
   2  * Copyright 2020 EfficiOS, Inc.
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #include "bytecode.h"
   9
  10 #include <errno.h>
  11
  12 #include "common/align.h"
  13
  14 #define INIT_ALLOC_SIZE 4
  15
  16 static inline
  17 int get_count_order(unsigned int count)
  18 {
  19         int order;
  20
  21         order = lttng_fls(count) - 1;
  22         if (count & (count - 1))
  23                 order++;
  24         return order;
  25 }
  26
  27 int bytecode_init(struct lttng_bytecode_alloc **fb)
  28 {
  29         uint32_t alloc_len;
  30
  31         alloc_len = sizeof(struct lttng_bytecode_alloc) + INIT_ALLOC_SIZE;
  32         *fb = calloc(alloc_len, 1);
  33         if (!*fb) {
  34                 return -ENOMEM;
  35         } else {
  36                 (*fb)->alloc_len = alloc_len;
  37                 return 0;
  38         }
  39 }
  40
  41 static
  42 int32_t bytecode_reserve(struct lttng_bytecode_alloc **fb, uint32_t align, uint32_t len)
  43 {
  44         int32_t ret;
  45         uint32_t padding = lttng_offset_align((*fb)->b.len, align);
  46         uint32_t new_len = (*fb)->b.len + padding + len;
  47         uint32_t new_alloc_len = sizeof(struct lttng_bytecode_alloc) + new_len;
  48         uint32_t old_alloc_len = (*fb)->alloc_len;
  49
  50         if (new_len > LTTNG_FILTER_MAX_LEN)
  51                 return -EINVAL;
  52
  53         if (new_alloc_len > old_alloc_len) {
  54                 struct lttng_bytecode_alloc *newptr;
  55
  56                 new_alloc_len =
  57                         max_t(uint32_t, 1U << get_count_order(new_alloc_len), old_alloc_len << 1);
  58                 newptr = realloc(*fb, new_alloc_len);
  59                 if (!newptr)
  60                         return -ENOMEM;
  61                 *fb = newptr;
  62                 /* We zero directly the memory from start of allocation. */
  63                 memset(&((char *) *fb)[old_alloc_len], 0, new_alloc_len - old_alloc_len);
  64                 (*fb)->alloc_len = new_alloc_len;
  65         }
  66         (*fb)->b.len += padding;
  67         ret = (*fb)->b.len;
  68         (*fb)->b.len += len;
  69         return ret;
  70 }
  71
  72 int bytecode_push(struct lttng_bytecode_alloc **fb, const void *data,
  73                 uint32_t align, uint32_t len)
  74 {
  75         int32_t offset;
  76
  77         offset = bytecode_reserve(fb, align, len);
  78         if (offset < 0)
  79                 return offset;
  80         memcpy(&(*fb)->b.data[offset], data, len);
  81         return 0;
  82 }
  83
  84 int bytecode_push_logical(struct lttng_bytecode_alloc **fb,
  85                 struct logical_op *data,
  86                 uint32_t align, uint32_t len,
  87                 uint16_t *skip_offset)
  88 {
  89         int32_t offset;
  90
  91         offset = bytecode_reserve(fb, align, len);
  92         if (offset < 0)
  93                 return offset;
  94         memcpy(&(*fb)->b.data[offset], data, len);
  95         *skip_offset =
  96                 (void *) &((struct logical_op *) &(*fb)->b.data[offset])->skip_offset
  97                         - (void *) &(*fb)->b.data[0];
  98         return 0;
  99 }
 100
 101 int bytecode_push_get_payload_root(struct lttng_bytecode_alloc **bytecode)
 102 {
 103         int ret;
 104         struct load_op *insn;
 105         const uint32_t insn_len = sizeof(struct load_op);
 106
 107         insn = calloc(insn_len, 1);
 108         if (!insn) {
 109                 ret = -ENOMEM;
 110                 goto end;
 111         }
 112
 113         insn->op = BYTECODE_OP_GET_PAYLOAD_ROOT;
 114         ret = bytecode_push(bytecode, insn, 1, insn_len);
 115         free(insn);
 116 end:
 117         return ret;
 118 }
 119
 120 int bytecode_push_get_context_root(struct lttng_bytecode_alloc **bytecode)
 121 {
 122         int ret;
 123         struct load_op *insn;
 124         const uint32_t insn_len = sizeof(struct load_op);
 125
 126         insn = calloc(insn_len, 1);
 127         if (!insn) {
 128                 ret = -ENOMEM;
 129                 goto end;
 130         }
 131
 132         insn->op = BYTECODE_OP_GET_CONTEXT_ROOT;
 133         ret = bytecode_push(bytecode, insn, 1, insn_len);
 134         free(insn);
 135 end:
 136         return ret;
 137 }
 138
 139 int bytecode_push_get_app_context_root(struct lttng_bytecode_alloc **bytecode)
 140 {
 141         int ret;
 142         struct load_op *insn;
 143         const uint32_t insn_len = sizeof(struct load_op);
 144
 145         insn = calloc(insn_len, 1);
 146         if (!insn) {
 147                 ret = -ENOMEM;
 148                 goto end;
 149         }
 150
 151         insn->op = BYTECODE_OP_GET_APP_CONTEXT_ROOT;
 152         ret = bytecode_push(bytecode, insn, 1, insn_len);
 153         free(insn);
 154 end:
 155         return ret;
 156 }
 157
 158 int bytecode_push_get_index_u64(struct lttng_bytecode_alloc **bytecode,
 159                 uint64_t index)
 160 {
 161         int ret;
 162         struct load_op *insn;
 163         struct get_index_u64 index_op_data;
 164         const uint32_t insn_len =
 165                         sizeof(struct load_op) + sizeof(struct get_index_u64);
 166
 167         insn = calloc(insn_len, 1);
 168         if (!insn) {
 169                 ret = -ENOMEM;
 170                 goto end;
 171         }
 172
 173         insn->op = BYTECODE_OP_GET_INDEX_U64;
 174         index_op_data.index = index;
 175         memcpy(insn->data, &index_op_data, sizeof(index));
 176         ret = bytecode_push(bytecode, insn, 1, insn_len);
 177
 178         free(insn);
 179 end:
 180         return ret;
 181 }
 182
 183 int bytecode_push_get_symbol(struct lttng_bytecode_alloc **bytecode,
 184                 struct lttng_bytecode_alloc **bytecode_reloc,
 185                 const char *symbol)
 186 {
 187         int ret;
 188         struct load_op *insn;
 189         struct get_symbol symbol_offset;
 190         uint32_t reloc_offset_u32;
 191         uint16_t reloc_offset;
 192         uint32_t bytecode_reloc_offset_u32;
 193         const uint32_t insn_len =
 194                         sizeof(struct load_op) + sizeof(struct get_symbol);
 195
 196         insn = calloc(insn_len, 1);
 197         if (!insn) {
 198                 ret = -ENOMEM;
 199                 goto end;
 200         }
 201
 202         insn->op = BYTECODE_OP_GET_SYMBOL;
 203
 204         /*
 205          * Get offset in the reloc portion at which the symbol name
 206          * will end up at (GET_SYMBOL's operand points there).
 207          */
 208         bytecode_reloc_offset_u32 = bytecode_get_len(&(*bytecode_reloc)->b) +
 209                         sizeof(reloc_offset);
 210         symbol_offset.offset = (uint16_t) bytecode_reloc_offset_u32;
 211         memcpy(insn->data, &symbol_offset, sizeof(symbol_offset));
 212
 213         /*
 214          * Get offset in the bytecode where the opcode will end up at,
 215          * the reloc offset points to it.
 216          */
 217         reloc_offset_u32 = bytecode_get_len(&(*bytecode)->b);
 218         if (reloc_offset_u32 > LTTNG_FILTER_MAX_LEN - 1) {
 219                 ret = -EINVAL;
 220                 goto end;
 221         }
 222         reloc_offset = (uint16_t) reloc_offset_u32;
 223
 224         /* Append op in bytecode. */
 225         ret = bytecode_push(bytecode, insn, 1, insn_len);
 226         if (ret) {
 227                 goto end;
 228         }
 229
 230         /* Append reloc offset. */
 231         ret = bytecode_push(bytecode_reloc, &reloc_offset,
 232                         1, sizeof(reloc_offset));
 233         if (ret) {
 234                 goto end;
 235         }
 236
 237         /* Append symbol name. */
 238         ret = bytecode_push(bytecode_reloc, symbol, 1, strlen(symbol) + 1);
 239
 240 end:
 241         free(insn);
 242         return ret;
 243 }
 244
 245 /*
 246  * Allocate an lttng_bytecode object and copy the given original bytecode.
 247  *
 248  * Return allocated bytecode or NULL on error.
 249  */
 250 struct lttng_bytecode *lttng_bytecode_copy(
 251                 const struct lttng_bytecode *orig_f)
 252 {
 253         struct lttng_bytecode *bytecode = NULL;
 254
 255         bytecode = zmalloc(sizeof(*bytecode) + orig_f->len);
 256         if (!bytecode) {
 257                 goto error;
 258         }
 259
 260         memcpy(bytecode, orig_f, sizeof(*bytecode) + orig_f->len);
 261
 262 error:
 263         return bytecode;
 264 }