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 bool lttng_buffer_view_is_valid(const struct lttng_buffer_view *view)
  23 {
  24         return view && view->data && view->size > 0;
  25 }
  26
  27 LTTNG_HIDDEN
  28 struct lttng_buffer_view lttng_buffer_view_from_view(
  29                 const struct lttng_buffer_view *src, size_t offset,
  30                 ptrdiff_t len)
  31 {
  32         struct lttng_buffer_view view = { .data = NULL, .size = 0 };
  33
  34         assert(src);
  35
  36         if (offset > src->size) {
  37                 ERR("Attempt to create buffer view from another view with invalid offset (offset > source size): source size = %zu, offset in source = %zu, length = %zd",
  38                                 src->size, offset, len);
  39                 goto end;
  40         }
  41
  42         if (len != -1 && len > (src->size - offset)) {
  43                 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",
  44                                 src->size, offset, len);
  45                 goto end;
  46         }
  47
  48         view.data = src->data + offset;
  49         view.size = len == -1 ? (src->size - offset) : len;
  50 end:
  51         return view;
  52 }
  53
  54 LTTNG_HIDDEN
  55 struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
  56                 const struct lttng_dynamic_buffer *src, size_t offset,
  57                 ptrdiff_t len)
  58 {
  59         struct lttng_buffer_view view = { .data = NULL, .size = 0 };
  60
  61         assert(src);
  62
  63         if (offset > src->size) {
  64                 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",
  65                                 src->size, offset, len);
  66                 goto end;
  67         }
  68
  69         if (len != -1 && len > (src->size - offset)) {
  70                 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",
  71                                 src->size, offset, 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 LTTNG_HIDDEN
  82 bool lttng_buffer_view_contains_string(const struct lttng_buffer_view *buf,
  83                 const char *str,
  84                 size_t len_with_null_terminator)
  85 {
  86         const char *past_buf_end;
  87         size_t max_str_len_with_null_terminator;
  88         size_t str_len;
  89         bool ret;
  90
  91         past_buf_end = buf->data + buf->size;
  92
  93         /* Is the start of the string in the buffer view? */
  94         if (str < buf->data || str >= past_buf_end) {
  95                 ret = false;
  96                 goto end;
  97         }
  98
  99         /*
 100          * Max length the string could have to fit in the buffer, including
 101          * NULL terminator.
 102          */
 103         max_str_len_with_null_terminator = past_buf_end - str;
 104
 105         /* Could the string even fit in the buffer? */
 106         if (len_with_null_terminator > max_str_len_with_null_terminator) {
 107                 ret = false;
 108                 goto end;
 109         }
 110
 111         str_len = lttng_strnlen(str, max_str_len_with_null_terminator);
 112         if (str_len != (len_with_null_terminator - 1)) {
 113                 ret = false;
 114                 goto end;
 115         }
 116
 117         ret = true;
 118
 119 end:
 120         return ret;
 121 }