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
  12 LTTNG_HIDDEN
  13 struct lttng_buffer_view lttng_buffer_view_init(
  14                 const char *src, size_t offset, ptrdiff_t len)
  15 {
  16         struct lttng_buffer_view view = { .data = src + offset, .size = len };
  17         return view;
  18 }
  19
  20 LTTNG_HIDDEN
  21 bool lttng_buffer_view_is_valid(const struct lttng_buffer_view *view)
  22 {
  23         return view && view->data && view->size > 0;
  24 }
  25
  26 LTTNG_HIDDEN
  27 struct lttng_buffer_view lttng_buffer_view_from_view(
  28                 const struct lttng_buffer_view *src, size_t offset,
  29                 ptrdiff_t len)
  30 {
  31         struct lttng_buffer_view view = { .data = NULL, .size = 0 };
  32
  33         LTTNG_ASSERT(src);
  34
  35         if (offset > src->size) {
  36                 ERR("Attempt to create buffer view from another view with invalid offset (offset > source size): source size = %zu, offset in source = %zu, length = %zd",
  37                                 src->size, offset, len);
  38                 goto end;
  39         }
  40
  41         if (len != -1 && len > (src->size - offset)) {
  42                 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",
  43                                 src->size, offset, len);
  44                 goto end;
  45         }
  46
  47         view.data = src->data + offset;
  48         view.size = len == -1 ? (src->size - offset) : len;
  49 end:
  50         return view;
  51 }
  52
  53 LTTNG_HIDDEN
  54 struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
  55                 const struct lttng_dynamic_buffer *src, size_t offset,
  56                 ptrdiff_t len)
  57 {
  58         struct lttng_buffer_view view = { .data = NULL, .size = 0 };
  59
  60         LTTNG_ASSERT(src);
  61
  62         if (offset > src->size) {
  63                 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",
  64                                 src->size, offset, len);
  65                 goto end;
  66         }
  67
  68         if (len != -1 && len > (src->size - offset)) {
  69                 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",
  70                                 src->size, offset, len);
  71                 goto end;
  72         }
  73
  74         view.data = src->data + offset;
  75         view.size = len == -1 ? (src->size - offset) : len;
  76 end:
  77         return view;
  78 }
  79
  80 LTTNG_HIDDEN
  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 }