src/common/bytecode/bytecode.cpp

   1 /*
   2  * Copyright 2020 EfficiOS, Inc.
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #include "bytecode.hpp"
   9 #include "common/align.hpp"
  10
  11 #include <algorithm>
  12 #include <errno.h>
  13
  14 #define INIT_ALLOC_SIZE 4
  15
  16 static inline int get_count_order(unsigned int count)
  17 {
  18         int order;
  19
  20         order = lttng_fls(count) - 1;
  21         if (count & (count - 1))
  22                 order++;
  23         return order;
  24 }
  25
  26 int bytecode_init(struct lttng_bytecode_alloc **fb)
  27 {
  28         uint32_t alloc_len;
  29
  30         alloc_len = sizeof(struct lttng_bytecode_alloc) + INIT_ALLOC_SIZE;
  31         *fb = (lttng_bytecode_alloc *) calloc(alloc_len, 1);
  32         if (!*fb) {
  33                 return -ENOMEM;
  34         } else {
  35                 (*fb)->alloc_len = alloc_len;
  36                 return 0;
  37         }
  38 }
  39
  40 static int32_t bytecode_reserve(struct lttng_bytecode_alloc **fb, uint32_t align, uint32_t len)
  41 {
  42         int32_t ret;
  43         uint32_t padding = lttng_offset_align((*fb)->b.len, align);
  44         uint32_t new_len = (*fb)->b.len + padding + len;
  45         uint32_t new_alloc_len = sizeof(struct lttng_bytecode_alloc) + new_len;
  46         uint32_t old_alloc_len = (*fb)->alloc_len;
  47
  48         if (new_len > LTTNG_FILTER_MAX_LEN)
  49                 return -EINVAL;
  50
  51         if (new_alloc_len > old_alloc_len) {
  52                 struct lttng_bytecode_alloc *newptr;
  53
  54                 new_alloc_len = std::max(1U << get_count_order(new_alloc_len), old_alloc_len << 1);
  55                 newptr = (lttng_bytecode_alloc *) realloc(*fb, new_alloc_len);
  56                 if (!newptr)
  57                         return -ENOMEM;
  58                 *fb = newptr;
  59                 /* We zero directly the memory from start of allocation. */
  60                 memset(&((char *) *fb)[old_alloc_len], 0, new_alloc_len - old_alloc_len);
  61                 (*fb)->alloc_len = new_alloc_len;
  62         }
  63         (*fb)->b.len += padding;
  64         ret = (*fb)->b.len;
  65         (*fb)->b.len += len;
  66         return ret;
  67 }
  68
  69 int bytecode_push(struct lttng_bytecode_alloc **fb, const void *data, uint32_t align, uint32_t len)
  70 {
  71         int32_t offset;
  72
  73         offset = bytecode_reserve(fb, align, len);
  74         if (offset < 0)
  75                 return offset;
  76         memcpy(&(*fb)->b.data[offset], data, len);
  77         return 0;
  78 }
  79
  80 int bytecode_push_logical(struct lttng_bytecode_alloc **fb,
  81                           struct logical_op *data,
  82                           uint32_t align,
  83                           uint32_t len,
  84                           uint16_t *skip_offset)
  85 {
  86         int32_t offset;
  87
  88         offset = bytecode_reserve(fb, align, len);
  89         if (offset < 0)
  90                 return offset;
  91         memcpy(&(*fb)->b.data[offset], data, len);
  92         *skip_offset = (char *) &((struct logical_op *) &(*fb)->b.data[offset])->skip_offset -
  93                 (char *) &(*fb)->b.data[0];
  94         return 0;
  95 }
  96
  97 int bytecode_push_get_payload_root(struct lttng_bytecode_alloc **bytecode)
  98 {
  99         int ret;
 100         struct load_op *insn;
 101         const uint32_t insn_len = sizeof(struct load_op);
 102
 103         insn = (load_op *) calloc(insn_len, 1);
 104         if (!insn) {
 105                 ret = -ENOMEM;
 106                 goto end;
 107         }
 108
 109         insn->op = BYTECODE_OP_GET_PAYLOAD_ROOT;
 110         ret = bytecode_push(bytecode, insn, 1, insn_len);
 111         free(insn);
 112 end:
 113         return ret;
 114 }
 115
 116 int bytecode_push_get_context_root(struct lttng_bytecode_alloc **bytecode)
 117 {
 118         int ret;
 119         struct load_op *insn;
 120         const uint32_t insn_len = sizeof(struct load_op);
 121
 122         insn = (load_op *) calloc(insn_len, 1);
 123         if (!insn) {
 124                 ret = -ENOMEM;
 125                 goto end;
 126         }
 127
 128         insn->op = BYTECODE_OP_GET_CONTEXT_ROOT;
 129         ret = bytecode_push(bytecode, insn, 1, insn_len);
 130         free(insn);
 131 end:
 132         return ret;
 133 }
 134
 135 int bytecode_push_get_app_context_root(struct lttng_bytecode_alloc **bytecode)
 136 {
 137         int ret;
 138         struct load_op *insn;
 139         const uint32_t insn_len = sizeof(struct load_op);
 140
 141         insn = (load_op *) calloc(insn_len, 1);
 142         if (!insn) {
 143                 ret = -ENOMEM;
 144                 goto end;
 145         }
 146
 147         insn->op = BYTECODE_OP_GET_APP_CONTEXT_ROOT;
 148         ret = bytecode_push(bytecode, insn, 1, insn_len);
 149         free(insn);
 150 end:
 151         return ret;
 152 }
 153
 154 int bytecode_push_get_index_u64(struct lttng_bytecode_alloc **bytecode, uint64_t index)
 155 {
 156         int ret;
 157         struct load_op *insn;
 158         struct get_index_u64 index_op_data;
 159         const uint32_t insn_len = sizeof(struct load_op) + sizeof(struct get_index_u64);
 160
 161         insn = (load_op *) calloc(insn_len, 1);
 162         if (!insn) {
 163                 ret = -ENOMEM;
 164                 goto end;
 165         }
 166
 167         insn->op = BYTECODE_OP_GET_INDEX_U64;
 168         index_op_data.index = index;
 169         memcpy(insn->data, &index_op_data, sizeof(index));
 170         ret = bytecode_push(bytecode, insn, 1, insn_len);
 171
 172         free(insn);
 173 end:
 174         return ret;
 175 }
 176
 177 int bytecode_push_get_symbol(struct lttng_bytecode_alloc **bytecode,
 178                              struct lttng_bytecode_alloc **bytecode_reloc,
 179                              const char *symbol)
 180 {
 181         int ret;
 182         struct load_op *insn;
 183         struct get_symbol symbol_offset;
 184         uint32_t reloc_offset_u32;
 185         uint16_t reloc_offset;
 186         uint32_t bytecode_reloc_offset_u32;
 187         const uint32_t insn_len = sizeof(struct load_op) + sizeof(struct get_symbol);
 188
 189         insn = (load_op *) calloc(insn_len, 1);
 190         if (!insn) {
 191                 ret = -ENOMEM;
 192                 goto end;
 193         }
 194
 195         insn->op = BYTECODE_OP_GET_SYMBOL;
 196
 197         /*
 198          * Get offset in the reloc portion at which the symbol name
 199          * will end up at (GET_SYMBOL's operand points there).
 200          */
 201         bytecode_reloc_offset_u32 = bytecode_get_len(&(*bytecode_reloc)->b) + sizeof(reloc_offset);
 202         symbol_offset.offset = (uint16_t) bytecode_reloc_offset_u32;
 203         memcpy(insn->data, &symbol_offset, sizeof(symbol_offset));
 204
 205         /*
 206          * Get offset in the bytecode where the opcode will end up at,
 207          * the reloc offset points to it.
 208          */
 209         reloc_offset_u32 = bytecode_get_len(&(*bytecode)->b);
 210         if (reloc_offset_u32 > LTTNG_FILTER_MAX_LEN - 1) {
 211                 ret = -EINVAL;
 212                 goto end;
 213         }
 214         reloc_offset = (uint16_t) reloc_offset_u32;
 215
 216         /* Append op in bytecode. */
 217         ret = bytecode_push(bytecode, insn, 1, insn_len);
 218         if (ret) {
 219                 goto end;
 220         }
 221
 222         /* Append reloc offset. */
 223         ret = bytecode_push(bytecode_reloc, &reloc_offset, 1, sizeof(reloc_offset));
 224         if (ret) {
 225                 goto end;
 226         }
 227
 228         /* Append symbol name. */
 229         ret = bytecode_push(bytecode_reloc, symbol, 1, strlen(symbol) + 1);
 230
 231 end:
 232         free(insn);
 233         return ret;
 234 }
 235
 236 /*
 237  * Allocate an lttng_bytecode object and copy the given original bytecode.
 238  *
 239  * Return allocated bytecode or NULL on error.
 240  */
 241 struct lttng_bytecode *lttng_bytecode_copy(const struct lttng_bytecode *orig_f)
 242 {
 243         lttng_bytecode *bytecode = zmalloc<lttng_bytecode>(sizeof(*bytecode) + orig_f->len);
 244         if (!bytecode) {
 245                 goto error;
 246         }
 247
 248         memcpy(bytecode, orig_f, sizeof(*bytecode) + orig_f->len);
 249
 250 error:
 251         return bytecode;
 252 }