Make the <android/dlext.h> docs show up on the web.
Just enough doxygen so that
https://developer.android.com/ndk/reference/dlext_8h.html won't be completely
devoid of all this.
Bug: N/A
Test: ran doxygen manually
Change-Id: I1e0667feae93227e32c1bd671065359f5be85d9d
diff --git a/libc/include/android/dlext.h b/libc/include/android/dlext.h
index c824544..2b4169e 100644
--- a/libc/include/android/dlext.h
+++ b/libc/include/android/dlext.h
@@ -23,88 +23,116 @@
#include <sys/cdefs.h>
#include <sys/types.h> /* for off64_t */
+/**
+ * \file
+ * Advanced dynamic library opening support. Most users will want to use
+ * the standard [dlopen(3)](http://man7.org/linux/man-pages/man3/dlopen.3.html)
+ * functionality in `<dlfcn.h>` instead.
+ */
+
__BEGIN_DECLS
-/* bitfield definitions for android_dlextinfo.flags */
+/** Bitfield definitions for `android_dlextinfo::flags`. */
enum {
- /* When set, the reserved_addr and reserved_size fields must point to an
+ /**
+ * When set, the `reserved_addr` and `reserved_size` fields must point to an
* already-reserved region of address space which will be used to load the
- * library if it fits. If the reserved region is not large enough, the load
- * will fail.
+ * library if it fits.
+ *
+ * If the reserved region is not large enough, loading will fail.
*/
ANDROID_DLEXT_RESERVED_ADDRESS = 0x1,
- /* As DLEXT_RESERVED_ADDRESS, but if the reserved region is not large enough,
+ /**
+ * Like `ANDROID_DLEXT_RESERVED_ADDRESS`, but if the reserved region is not large enough,
* the linker will choose an available address instead.
*/
ANDROID_DLEXT_RESERVED_ADDRESS_HINT = 0x2,
- /* When set, write the GNU RELRO section of the mapped library to relro_fd
+ /**
+ * When set, write the GNU RELRO section of the mapped library to `relro_fd`
* after relocation has been performed, to allow it to be reused by another
* process loading the same library at the same address. This implies
- * ANDROID_DLEXT_USE_RELRO.
+ * `ANDROID_DLEXT_USE_RELRO`.
+ *
+ * This is mainly useful for the system WebView implementation.
*/
ANDROID_DLEXT_WRITE_RELRO = 0x4,
- /* When set, compare the GNU RELRO section of the mapped library to relro_fd
+ /**
+ * When set, compare the GNU RELRO section of the mapped library to `relro_fd`
* after relocation has been performed, and replace any relocated pages that
* are identical with a version mapped from the file.
+ *
+ * This is mainly useful for the system WebView implementation.
*/
ANDROID_DLEXT_USE_RELRO = 0x8,
- /* Instruct dlopen to use library_fd instead of opening file by name.
+ /**
+ * Use `library_fd` instead of opening the file by name.
* The filename parameter is still used to identify the library.
*/
ANDROID_DLEXT_USE_LIBRARY_FD = 0x10,
- /* If opening a library using library_fd read it starting at library_fd_offset.
- * This flag is only valid when ANDROID_DLEXT_USE_LIBRARY_FD is set.
+ /**
+ * If opening a library using `library_fd` read it starting at `library_fd_offset`.
+ * This is mainly useful for loading a library stored within another file (such as uncompressed
+ * inside a ZIP archive).
+ * This flag is only valid when `ANDROID_DLEXT_USE_LIBRARY_FD` is set.
*/
ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET = 0x20,
- /* When set, do not check if the library has already been loaded by file stat(2)s.
+ /**
+ * When set, do not use `stat(2)` to check if the library has already been loaded.
*
* This flag allows forced loading of the library in the case when for some
* reason multiple ELF files share the same filename (because the already-loaded
* library has been removed and overwritten, for example).
*
- * Note that if the library has the same dt_soname as an old one and some other
- * library has the soname in DT_NEEDED list, the first one will be used to resolve any
+ * Note that if the library has the same `DT_SONAME` as an old one and some other
+ * library has the soname in its `DT_NEEDED` list, the first one will be used to resolve any
* dependencies.
*/
ANDROID_DLEXT_FORCE_LOAD = 0x40,
- /* When set, if the minimum p_vaddr of the ELF file's PT_LOAD segments is non-zero,
+ /**
+ * When set, if the minimum `p_vaddr` of the ELF file's `PT_LOAD` segments is non-zero,
* the dynamic linker will load it at that address.
*
* This flag is for ART internal use only.
*/
ANDROID_DLEXT_FORCE_FIXED_VADDR = 0x80,
- /* Instructs dlopen to load the library at the address specified by reserved_addr.
+ /**
+ * Instructs dlopen to load the library at the address specified by reserved_addr.
*
- * The difference between ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS and ANDROID_DLEXT_RESERVED_ADDRESS
- * is that for ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS the linker reserves memory at reserved_addr
- * whereas for ANDROID_DLEXT_RESERVED_ADDRESS the linker relies on the caller to reserve the memory.
+ * The difference between `ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS` and
+ * `ANDROID_DLEXT_RESERVED_ADDRESS` is that for `ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS` the linker
+ * reserves memory at `reserved_addr` whereas for `ANDROID_DLEXT_RESERVED_ADDRESS` the linker
+ * relies on the caller to reserve the memory.
*
- * This flag can be used with ANDROID_DLEXT_FORCE_FIXED_VADDR; when ANDROID_DLEXT_FORCE_FIXED_VADDR
- * is set and load_bias is not 0 (load_bias is min(p_vaddr) of PT_LOAD segments) this flag is ignored.
- * This is implemented this way because the linker has to pick one address over the other and this
- * way is more convenient for art. Note that ANDROID_DLEXT_FORCE_FIXED_VADDR does not generate
- * an error when min(p_vaddr) is 0.
+ * This flag can be used with `ANDROID_DLEXT_FORCE_FIXED_VADDR`. When
+ * `ANDROID_DLEXT_FORCE_FIXED_VADDR` is set and `load_bias` is not 0 (`load_bias` is the
+ * minimum `p_vaddr` of all `PT_LOAD` segments) this flag is ignored because the linker has to
+ * pick one address over the other and this way is more convenient for ART.
+ * Note that `ANDROID_DLEXT_FORCE_FIXED_VADDR` does not generate an error when the minimum
+ * `p_vaddr` is 0.
*
- * Cannot be used with ANDROID_DLEXT_RESERVED_ADDRESS or ANDROID_DLEXT_RESERVED_ADDRESS_HINT.
+ * Cannot be used with `ANDROID_DLEXT_RESERVED_ADDRESS` or `ANDROID_DLEXT_RESERVED_ADDRESS_HINT`.
*
* This flag is for ART internal use only.
*/
ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS = 0x100,
- /* This flag used to load library in a different namespace. The namespace is
- * specified in library_namespace.
+ /**
+ * This flag used to load library in a different namespace. The namespace is
+ * specified in `library_namespace`.
+ *
+ * This flag is for internal use only (since there is no NDK API for namespaces).
*/
ANDROID_DLEXT_USE_NAMESPACE = 0x200,
- /* Mask of valid bits */
+ /** Mask of valid bits. */
ANDROID_DLEXT_VALID_FLAG_BITS = ANDROID_DLEXT_RESERVED_ADDRESS |
ANDROID_DLEXT_RESERVED_ADDRESS_HINT |
ANDROID_DLEXT_WRITE_RELRO |
@@ -119,19 +147,36 @@
struct android_namespace_t;
+/** Used to pass Android-specific arguments to `android_dlopen_ext`. */
typedef struct {
+ /** A bitmask of `ANDROID_DLEXT_` enum values. */
uint64_t flags;
+
+ /** Used by `ANDROID_DLEXT_RESERVED_ADDRESS` and `ANDROID_DLEXT_RESERVED_ADDRESS_HINT`. */
void* reserved_addr;
+ /** Used by `ANDROID_DLEXT_RESERVED_ADDRESS` and `ANDROID_DLEXT_RESERVED_ADDRESS_HINT`. */
size_t reserved_size;
+
+ /** Used by `ANDROID_DLEXT_WRITE_RELRO` and `ANDROID_DLEXT_USE_RELRO`. */
int relro_fd;
+
+ /** Used by `ANDROID_DLEXT_USE_LIBRARY_FD`. */
int library_fd;
+ /** Used by `ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET` */
off64_t library_fd_offset;
+
+ /** Used by `ANDROID_DLEXT_USE_NAMESPACE`. */
struct android_namespace_t* library_namespace;
} android_dlextinfo;
+/**
+ * Opens the given library. The `__filename` and `__flags` arguments are
+ * the same as for [dlopen(3)](http://man7.org/linux/man-pages/man3/dlopen.3.html),
+ * with the Android-specific flags supplied via the `flags` member of `__info`.
+ */
void* android_dlopen_ext(const char* __filename, int __flags, const android_dlextinfo* __info)
__INTRODUCED_IN(21);
__END_DECLS
-#endif /* __ANDROID_DLEXT_H__ */
+#endif