src/common/buffer-view.cpp

   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.hpp>
   9 #include <common/dynamic-buffer.hpp>
  10 #include <common/error.hpp>
  11
  12 struct lttng_buffer_view lttng_buffer_view_init(const char *src, size_t offset, ptrdiff_t len)
  13 {
  14         struct lttng_buffer_view view = { .data = src + offset, .size = (size_t) len };
  15         return view;
  16 }
  17
  18 bool lttng_buffer_view_is_valid(const struct lttng_buffer_view *view)
  19 {
  20         return view && view->data && view->size > 0;
  21 }
  22
  23 struct lttng_buffer_view
  24 lttng_buffer_view_from_view(const struct lttng_buffer_view *src, size_t offset, ptrdiff_t len)
  25 {
  26         struct lttng_buffer_view view = { .data = NULL, .size = 0 };
  27
  28         LTTNG_ASSERT(src);
  29
  30         if (offset > src->size) {
  31                 ERR("Attempt to create buffer view from another view with invalid offset (offset > source size): source size = %zu, offset in source = %zu, length = %zd",
  32                     src->size,
  33                     offset,
  34                     len);
  35                 goto end;
  36         }
  37
  38         if (len != -1 && len > (src->size - offset)) {
  39                 ERR("Attempt to create buffer view from another view with invalid length (length > space left after offset in source): source size = %zu, offset in source = %zu, length = %zd",
  40                     src->size,
  41                     offset,
  42                     len);
  43                 goto end;
  44         }
  45
  46         view.data = src->data + offset;
  47         view.size = len == -1 ? (src->size - offset) : len;
  48 end:
  49         return view;
  50 }
  51
  52 struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
  53         const struct lttng_dynamic_buffer *src, size_t offset, ptrdiff_t len)
  54 {
  55         struct lttng_buffer_view view = { .data = NULL, .size = 0 };
  56
  57         LTTNG_ASSERT(src);
  58
  59         if (offset > src->size) {
  60                 ERR("Attempt to create buffer view from a dynamic buffer with invalid offset (offset > source size): source size = %zu, offset in source = %zu, length = %zd",
  61                     src->size,
  62                     offset,
  63                     len);
  64                 goto end;
  65         }
  66
  67         if (len != -1 && len > (src->size - offset)) {
  68                 ERR("Attempt to create buffer view from a dynamic buffer with invalid length (length > space left after offset in source): source size = %zu, offset in source = %zu, length = %zd",
  69                     src->size,
  70                     offset,
  71                     len);
  72                 goto end;
  73         }
  74
  75         view.data = src->data + offset;
  76         view.size = len == -1 ? (src->size - offset) : len;
  77 end:
  78         return view;
  79 }
  80
  81 bool lttng_buffer_view_contains_string(const struct lttng_buffer_view *buf,
  82                                        const char *str,
  83                                        size_t len_with_null_terminator)
  84 {
  85         const char *past_buf_end;
  86         size_t max_str_len_with_null_terminator;
  87         size_t str_len;
  88         bool ret;
  89
  90         past_buf_end = buf->data + buf->size;
  91
  92         /* Is the start of the string in the buffer view? */
  93         if (str < buf->data || str >= past_buf_end) {
  94                 ret = false;
  95                 goto end;
  96         }
  97
  98         /*
  99          * Max length the string could have to fit in the buffer, including
 100          * NULL terminator.
 101          */
 102         max_str_len_with_null_terminator = past_buf_end - str;
 103
 104         /* Could the string even fit in the buffer? */
 105         if (len_with_null_terminator > max_str_len_with_null_terminator) {
 106                 ret = false;
 107                 goto end;
 108         }
 109
 110         str_len = lttng_strnlen(str, max_str_len_with_null_terminator);
 111         if (str_len != (len_with_null_terminator - 1)) {
 112                 ret = false;
 113                 goto end;
 114         }
 115
 116         ret = true;
 117
 118 end:
 119         return ret;
 120 }