Fix: increment buffer offset when failing to copy from user-space

[lttng-modules.git] / include / ringbuffer / backend.h

diff --git a/include/ringbuffer/backend.h b/include/ringbuffer/backend.h
index 1f499c90a25804a9dc131690eba4397af3489377..1ede713c82de37233c54c86b1b4b20c41e1a7824 100644 (file)
--- a/include/ringbuffer/backend.h
+++ b/include/ringbuffer/backend.h
@@ -31,18 +31,18 @@
 
 /* Ring buffer backend access (read/write) */
 
-extern size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb,
+extern size_t lib_ring_buffer_read(struct lttng_kernel_ring_buffer_backend *bufb,
                                   size_t offset, void *dest, size_t len);
 
-extern int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb,
+extern int __lib_ring_buffer_copy_to_user(struct lttng_kernel_ring_buffer_backend *bufb,
                                          size_t offset, void __user *dest,
                                          size_t len);
 
-extern int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb,
+extern int lib_ring_buffer_read_cstr(struct lttng_kernel_ring_buffer_backend *bufb,
                                     size_t offset, void *dest, size_t len);
 
 extern unsigned long *
-lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, size_t offset,
+lib_ring_buffer_read_get_pfn(struct lttng_kernel_ring_buffer_backend *bufb, size_t offset,
                              void ***virt);
 
 /*
@@ -52,10 +52,10 @@ lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, size_t offset
  * as long as the write is never bigger than a page size.
  */
 extern void *
-lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb,
+lib_ring_buffer_offset_address(struct lttng_kernel_ring_buffer_backend *bufb,
                               size_t offset);
 extern void *
-lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb,
+lib_ring_buffer_read_offset_address(struct lttng_kernel_ring_buffer_backend *bufb,
                                    size_t offset);
 
 /**
@@ -71,15 +71,15 @@ lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb,
  * if copy is crossing a page boundary.
  */
 static inline __attribute__((always_inline))
-void lib_ring_buffer_write(const struct lib_ring_buffer_config *config,
-                          struct lib_ring_buffer_ctx *ctx,
+void lib_ring_buffer_write(const struct lttng_kernel_ring_buffer_config *config,
+                          struct lttng_kernel_ring_buffer_ctx *ctx,
                           const void *src, size_t len)
 {
-       struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
-       struct channel_backend *chanb = &ctx->chan->backend;
+       struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend;
+       struct channel_backend *chanb = &ctx->priv.chan->backend;
        size_t index, pagecpy;
-       size_t offset = ctx->buf_offset;
-       struct lib_ring_buffer_backend_pages *backend_pages;
+       size_t offset = ctx->priv.buf_offset;
+       struct lttng_kernel_ring_buffer_backend_pages *backend_pages;
 
        if (unlikely(!len))
                return;
@@ -95,7 +95,7 @@ void lib_ring_buffer_write(const struct lib_ring_buffer_config *config,
                                        src, len);
        else
                _lib_ring_buffer_write(bufb, offset, src, len, 0);
-       ctx->buf_offset += len;
+       ctx->priv.buf_offset += len;
 }
 
 /**
@@ -112,15 +112,15 @@ void lib_ring_buffer_write(const struct lib_ring_buffer_config *config,
  * boundary.
  */
 static inline
-void lib_ring_buffer_memset(const struct lib_ring_buffer_config *config,
-                           struct lib_ring_buffer_ctx *ctx, int c, size_t len)
+void lib_ring_buffer_memset(const struct lttng_kernel_ring_buffer_config *config,
+                           struct lttng_kernel_ring_buffer_ctx *ctx, int c, size_t len)
 {
 
-       struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
-       struct channel_backend *chanb = &ctx->chan->backend;
+       struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend;
+       struct channel_backend *chanb = &ctx->priv.chan->backend;
        size_t index, pagecpy;
-       size_t offset = ctx->buf_offset;
-       struct lib_ring_buffer_backend_pages *backend_pages;
+       size_t offset = ctx->priv.buf_offset;
+       struct lttng_kernel_ring_buffer_backend_pages *backend_pages;
 
        if (unlikely(!len))
                return;
@@ -135,7 +135,7 @@ void lib_ring_buffer_memset(const struct lib_ring_buffer_config *config,
                                          c, len);
        else
                _lib_ring_buffer_memset(bufb, offset, c, len, 0);
-       ctx->buf_offset += len;
+       ctx->priv.buf_offset += len;
 }
 
 /*
@@ -144,7 +144,7 @@ void lib_ring_buffer_memset(const struct lib_ring_buffer_config *config,
  * copied. Does *not* terminate @dest with NULL terminating character.
  */
 static inline __attribute__((always_inline))
-size_t lib_ring_buffer_do_strcpy(const struct lib_ring_buffer_config *config,
+size_t lib_ring_buffer_do_strcpy(const struct lttng_kernel_ring_buffer_config *config,
                char *dest, const char *src, size_t len)
 {
        size_t count;
@@ -156,7 +156,7 @@ size_t lib_ring_buffer_do_strcpy(const struct lib_ring_buffer_config *config,
                 * Only read source character once, in case it is
                 * modified concurrently.
                 */
-               c = READ_ONCE(src[count]);
+               c = LTTNG_READ_ONCE(src[count]);
                if (!c)
                        break;
                lib_ring_buffer_do_copy(config, &dest[count], &c, 1);
@@ -175,7 +175,7 @@ size_t lib_ring_buffer_do_strcpy(const struct lib_ring_buffer_config *config,
  * previously.
  */
 static inline __attribute__((always_inline))
-size_t lib_ring_buffer_do_strcpy_from_user_inatomic(const struct lib_ring_buffer_config *config,
+size_t lib_ring_buffer_do_strcpy_from_user_inatomic(const struct lttng_kernel_ring_buffer_config *config,
                char *dest, const char __user *src, size_t len)
 {
        size_t count;
@@ -209,15 +209,15 @@ size_t lib_ring_buffer_do_strcpy_from_user_inatomic(const struct lib_ring_buffer
  * (_ring_buffer_strcpy) if copy is crossing a page boundary.
  */
 static inline
-void lib_ring_buffer_strcpy(const struct lib_ring_buffer_config *config,
-                          struct lib_ring_buffer_ctx *ctx,
+void lib_ring_buffer_strcpy(const struct lttng_kernel_ring_buffer_config *config,
+                          struct lttng_kernel_ring_buffer_ctx *ctx,
                           const char *src, size_t len, int pad)
 {
-       struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
-       struct channel_backend *chanb = &ctx->chan->backend;
+       struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend;
+       struct channel_backend *chanb = &ctx->priv.chan->backend;
        size_t index, pagecpy;
-       size_t offset = ctx->buf_offset;
-       struct lib_ring_buffer_backend_pages *backend_pages;
+       size_t offset = ctx->priv.buf_offset;
+       struct lttng_kernel_ring_buffer_backend_pages *backend_pages;
 
        if (unlikely(!len))
                return;
@@ -250,7 +250,7 @@ void lib_ring_buffer_strcpy(const struct lib_ring_buffer_config *config,
        } else {
                _lib_ring_buffer_strcpy(bufb, offset, src, len, 0, pad);
        }
-       ctx->buf_offset += len;
+       ctx->priv.buf_offset += len;
 }
 
 /**
@@ -267,17 +267,16 @@ void lib_ring_buffer_strcpy(const struct lib_ring_buffer_config *config,
  * Disable the page fault handler to ensure we never try to take the mmap_sem.
  */
 static inline __attribute__((always_inline))
-void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config *config,
-                                   struct lib_ring_buffer_ctx *ctx,
+void lib_ring_buffer_copy_from_user_inatomic(const struct lttng_kernel_ring_buffer_config *config,
+                                   struct lttng_kernel_ring_buffer_ctx *ctx,
                                    const void __user *src, size_t len)
 {
-       struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
-       struct channel_backend *chanb = &ctx->chan->backend;
+       struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend;
+       struct channel_backend *chanb = &ctx->priv.chan->backend;
        size_t index, pagecpy;
-       size_t offset = ctx->buf_offset;
-       struct lib_ring_buffer_backend_pages *backend_pages;
+       size_t offset = ctx->priv.buf_offset;
+       struct lttng_kernel_ring_buffer_backend_pages *backend_pages;
        unsigned long ret;
-       mm_segment_t old_fs = get_fs();
 
        if (unlikely(!len))
                return;
@@ -287,7 +286,6 @@ void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config
        index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
        pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
 
-       set_fs(KERNEL_DS);
        pagefault_disable();
        if (unlikely(!lttng_access_ok(VERIFY_READ, src, len)))
                goto fill_buffer;
@@ -304,19 +302,18 @@ void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config
                _lib_ring_buffer_copy_from_user_inatomic(bufb, offset, src, len, 0);
        }
        pagefault_enable();
-       set_fs(old_fs);
-       ctx->buf_offset += len;
+       ctx->priv.buf_offset += len;
 
        return;
 
 fill_buffer:
        pagefault_enable();
-       set_fs(old_fs);
        /*
         * In the error path we call the slow path version to avoid
         * the pollution of static inline code.
         */
        _lib_ring_buffer_memset(bufb, offset, 0, len, 0);
+       ctx->priv.buf_offset += len;
 }
 
 /**
@@ -338,16 +335,15 @@ fill_buffer:
  * take the mmap_sem.
  */
 static inline
-void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_config *config,
-               struct lib_ring_buffer_ctx *ctx,
+void lib_ring_buffer_strcpy_from_user_inatomic(const struct lttng_kernel_ring_buffer_config *config,
+               struct lttng_kernel_ring_buffer_ctx *ctx,
                const void __user *src, size_t len, int pad)
 {
-       struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
-       struct channel_backend *chanb = &ctx->chan->backend;
+       struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend;
+       struct channel_backend *chanb = &ctx->priv.chan->backend;
        size_t index, pagecpy;
-       size_t offset = ctx->buf_offset;
-       struct lib_ring_buffer_backend_pages *backend_pages;
-       mm_segment_t old_fs = get_fs();
+       size_t offset = ctx->priv.buf_offset;
+       struct lttng_kernel_ring_buffer_backend_pages *backend_pages;
 
        if (unlikely(!len))
                return;
@@ -357,7 +353,6 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_conf
        index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
        pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
 
-       set_fs(KERNEL_DS);
        pagefault_disable();
        if (unlikely(!lttng_access_ok(VERIFY_READ, src, len)))
                goto fill_buffer;
@@ -388,14 +383,12 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_conf
                                        len, 0, pad);
        }
        pagefault_enable();
-       set_fs(old_fs);
-       ctx->buf_offset += len;
+       ctx->priv.buf_offset += len;
 
        return;
 
 fill_buffer:
        pagefault_enable();
-       set_fs(old_fs);
        /*
         * In the error path we call the slow path version to avoid
         * the pollution of static inline code.
@@ -403,6 +396,7 @@ fill_buffer:
        _lib_ring_buffer_memset(bufb, offset, pad, len - 1, 0);
        offset += len - 1;
        _lib_ring_buffer_memset(bufb, offset, '\0', 1, 0);
+       ctx->priv.buf_offset += len;
 }
 
 /*
@@ -412,11 +406,11 @@ fill_buffer:
  */
 static inline
 unsigned long lib_ring_buffer_get_records_unread(
-                               const struct lib_ring_buffer_config *config,
-                               struct lib_ring_buffer *buf)
+                               const struct lttng_kernel_ring_buffer_config *config,
+                               struct lttng_kernel_ring_buffer *buf)
 {
-       struct lib_ring_buffer_backend *bufb = &buf->backend;
-       struct lib_ring_buffer_backend_pages *pages;
+       struct lttng_kernel_ring_buffer_backend *bufb = &buf->backend;
+       struct lttng_kernel_ring_buffer_backend_pages *pages;
        unsigned long records_unread = 0, sb_bindex, id;
        unsigned int i;
 
@@ -447,16 +441,12 @@ unsigned long lib_ring_buffer_copy_from_user_check_nofault(void *dest,
                                                unsigned long len)
 {
        unsigned long ret;
-       mm_segment_t old_fs;
 
        if (!lttng_access_ok(VERIFY_READ, src, len))
                return 1;
-       old_fs = get_fs();
-       set_fs(KERNEL_DS);
        pagefault_disable();
        ret = __copy_from_user_inatomic(dest, src, len);
        pagefault_enable();
-       set_fs(old_fs);
        return ret;
 }