ctx->priv.buf_offset += len;
}
+/**
+ * lib_ring_buffer_pstrcpy - write kernel C-string (input) to a buffer backend P-string
+ * @config : ring buffer instance configuration
+ * @ctx: ring buffer context. (input arguments only)
+ * @src : source pointer to copy from
+ * @len : length of data to copy
+ * @pad : character to use for padding
+ *
+ * This function copies up to @len bytes of data from a source pointer
+ * to a Pascal String into the buffer backend. If a terminating '\0'
+ * character is found in @src before @len characters are copied, pad the
+ * buffer with @pad characters (e.g. '\0').
+ *
+ * The length of the pascal strings in the ring buffer is explicit: it
+ * is either the array or sequence length.
+ */
+static inline
+void lib_ring_buffer_pstrcpy(const struct lttng_kernel_ring_buffer_config *config,
+ struct lttng_kernel_ring_buffer_ctx *ctx,
+ const char *src, size_t len, char pad)
+ __attribute__((always_inline));
+static inline
+void lib_ring_buffer_pstrcpy(const struct lttng_kernel_ring_buffer_config *config,
+ struct lttng_kernel_ring_buffer_ctx *ctx,
+ const char *src, size_t len, char pad)
+{
+ struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend;
+ struct channel_backend *chanb = &ctx->priv.chan->backend;
+ size_t index, bytes_left_in_page;
+ size_t offset = ctx->priv.buf_offset;
+ struct lttng_kernel_ring_buffer_backend_pages *backend_pages;
+
+ if (unlikely(!len))
+ return;
+ backend_pages =
+ lib_ring_buffer_get_backend_pages_from_ctx(config, ctx);
+ offset &= chanb->buf_size - 1;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ bytes_left_in_page = min_t(size_t, len, (-offset) & ~PAGE_MASK);
+ if (likely(bytes_left_in_page == len)) {
+ size_t count;
+
+ count = lib_ring_buffer_do_strcpy(config,
+ backend_pages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ src, len);
+ offset += count;
+ /* Padding */
+ if (unlikely(count < len)) {
+ size_t pad_len = len - count;
+
+ lib_ring_buffer_do_memset(backend_pages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ pad, pad_len);
+ offset += pad_len;
+ }
+ } else {
+ _lib_ring_buffer_pstrcpy(bufb, offset, src, len, pad);
+ }
+ ctx->priv.buf_offset += len;
+}
+
/**
* lib_ring_buffer_copy_from_user_inatomic - write userspace data to a buffer backend
* @config : ring buffer instance configuration
ctx->priv.buf_offset += len;
}
+/**
+ * lib_ring_buffer_pstrcpy_from_user_inatomic - write user-space C-string (input) to a buffer backend P-string
+ * @config : ring buffer instance configuration
+ * @ctx: ring buffer context. (input arguments only)
+ * @src : source pointer to copy from
+ * @len : length of data to copy
+ * @pad : character to use for padding
+ *
+ * This function copies up to @len bytes of data from a source pointer
+ * to a Pascal String into the buffer backend. If a terminating '\0'
+ * character is found in @src before @len characters are copied, pad the
+ * buffer with @pad characters (e.g. '\0').
+ *
+ * The length of the pascal strings in the ring buffer is explicit: it
+ * is either the array or sequence length.
+ */
+static inline
+void lib_ring_buffer_pstrcpy_from_user_inatomic(const struct lttng_kernel_ring_buffer_config *config,
+ struct lttng_kernel_ring_buffer_ctx *ctx,
+ const char __user *src, size_t len, char pad)
+ __attribute__((always_inline));
+static inline
+void lib_ring_buffer_pstrcpy_from_user_inatomic(const struct lttng_kernel_ring_buffer_config *config,
+ struct lttng_kernel_ring_buffer_ctx *ctx,
+ const char __user *src, size_t len, char pad)
+{
+ struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend;
+ struct channel_backend *chanb = &ctx->priv.chan->backend;
+ size_t index, bytes_left_in_page;
+ size_t offset = ctx->priv.buf_offset;
+ struct lttng_kernel_ring_buffer_backend_pages *backend_pages;
+
+ if (unlikely(!len))
+ return;
+ backend_pages =
+ lib_ring_buffer_get_backend_pages_from_ctx(config, ctx);
+ offset &= chanb->buf_size - 1;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ bytes_left_in_page = min_t(size_t, len, (-offset) & ~PAGE_MASK);
+
+ if (unlikely(!lttng_access_ok(VERIFY_READ, src, len)))
+ goto fill_buffer;
+
+ pagefault_disable();
+ if (likely(bytes_left_in_page == len)) {
+ size_t count;
+
+ count = lib_ring_buffer_do_strcpy_from_user_inatomic(config,
+ backend_pages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ src, len);
+ offset += count;
+ /* Padding */
+ if (unlikely(count < len)) {
+ size_t pad_len = len - count;
+
+ lib_ring_buffer_do_memset(backend_pages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ pad, pad_len);
+ offset += pad_len;
+ }
+ } else {
+ _lib_ring_buffer_pstrcpy_from_user_inatomic(bufb, offset, src, len, pad);
+ }
+ ctx->priv.buf_offset += len;
+ pagefault_enable();
+
+ return;
+
+fill_buffer:
+ /*
+ * In the error path we call the slow path version to avoid
+ * the pollution of static inline code.
+ */
+ _lib_ring_buffer_memset(bufb, offset, pad, len, 0);
+ ctx->priv.buf_offset += len;
+}
+
/*
* This accessor counts the number of unread records in a buffer.
* It only provides a consistent value if no reads not writes are performed
projects / lttng-modules.git / blobdiff