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