src/common/buffer-view.c

   1 /*
   2  * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #include <common/buffer-view.h>
   9 #include <common/dynamic-buffer.h>
  10 #include <common/error.h>
  11 #include <assert.h>
  12
  13 LTTNG_HIDDEN
  14 struct lttng_buffer_view lttng_buffer_view_init(
  15                 const char *src, size_t offset, ptrdiff_t len)
  16 {
  17         struct lttng_buffer_view view = { .data = src + offset, .size = len };
  18         return view;
  19 }
  20
  21 LTTNG_HIDDEN
  22 struct lttng_buffer_view lttng_buffer_view_from_view(
  23                 const struct lttng_buffer_view *src, size_t offset,
  24                 ptrdiff_t len)
  25 {
  26         struct lttng_buffer_view view = { .data = NULL, .size = 0 };
  27
  28         assert(src);
  29
  30         if (offset > src->size) {
  31                 ERR("Attempt to create buffer view with invalid offset");
  32                 goto end;
  33         }
  34
  35         if (len != -1 && len > (src->size - offset)) {
  36                 ERR("Attempt to create buffer view with invalid length");
  37                 goto end;
  38         }
  39
  40         view.data = src->data + offset;
  41         view.size = len == -1 ? (src->size - offset) : len;
  42 end:
  43         return view;
  44 }
  45
  46 LTTNG_HIDDEN
  47 struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
  48                 const struct lttng_dynamic_buffer *src, size_t offset,
  49                 ptrdiff_t len)
  50 {
  51         struct lttng_buffer_view view = { .data = NULL, .size = 0 };
  52
  53         assert(src);
  54
  55         if (offset > src->size) {
  56                 ERR("Attempt to create buffer view with invalid offset");
  57                 goto end;
  58         }
  59
  60         if (len != -1 && len > (src->size - offset)) {
  61                 ERR("Attempt to create buffer view with invalid length");
  62                 goto end;
  63         }
  64
  65         view.data = src->data + offset;
  66         view.size = len == -1 ? (src->size - offset) : len;
  67 end:
  68         return view;
  69 }
  70
  71 LTTNG_HIDDEN
  72 bool lttng_buffer_view_contains_string(const struct lttng_buffer_view *buf,
  73                 const char *str,
  74                 size_t len_with_null_terminator)
  75 {
  76         const char *past_buf_end;
  77         size_t max_str_len_with_null_terminator;
  78         size_t str_len;
  79         bool ret;
  80
  81         past_buf_end = buf->data + buf->size;
  82
  83         /* Is the start of the string in the buffer view? */
  84         if (str < buf->data || str >= past_buf_end) {
  85                 ret = false;
  86                 goto end;
  87         }
  88
  89         /*
  90          * Max length the string could have to fit in the buffer, including
  91          * NULL terminator.
  92          */
  93         max_str_len_with_null_terminator = past_buf_end - str;
  94
  95         /* Could the string even fit in the buffer? */
  96         if (len_with_null_terminator > max_str_len_with_null_terminator) {
  97                 ret = false;
  98                 goto end;
  99         }
 100
 101         str_len = lttng_strnlen(str, max_str_len_with_null_terminator);
 102         if (str_len != (len_with_null_terminator - 1)) {
 103                 ret = false;
 104                 goto end;
 105         }
 106
 107         ret = true;
 108
 109 end:
 110         return ret;
 111 }