Improve readme.

README.md

@@ -142,7 +142,7 @@ void *xdl_open(const char *filename, int flags);
 void *xdl_close(void *handle);
 ```
 
-They are very similar to `dlopen()` and `dlclose()`. But `xdl_open()` can bypass the restrictions of Android 7.0+ linker namespace.
+They are very similar to [`dlopen()`](https://man7.org/linux/man-pages/man3/dlopen.3.html) and [`dlclose()`](https://man7.org/linux/man-pages/man3/dlclose.3.html). But `xdl_open()` can bypass the restrictions of Android 7.0+ linker namespace.
 
 Depending on the value of the `flags` parameter, the behavior of `xdl_open()` will have some differences:
 
@@ -176,7 +176,7 @@ void *xdl_sym(void *handle, const char *symbol, size_t *symbol_size);
 void *xdl_dsym(void *handle, const char *symbol, size_t *symbol_size);
 ```
 
-They are very similar to `dlsym()`. They all takes a "handle" of an ELF returned by `xdl_open()` and the null-terminated symbol name, returning the address where that symbol is loaded into memory.
+They are very similar to [`dlsym()`](https://man7.org/linux/man-pages/man3/dlsym.3.html). They all takes a "handle" of an ELF returned by `xdl_open()` and the null-terminated symbol name, returning the address where that symbol is loaded into memory.
 
 If the `symbol_size` parameter is not `NULL`, it will be assigned as "the bytes occupied by the content corresponding to the symbol in the ELF". If you don't need this information, just pass `NULL`.
 
@@ -193,18 +193,30 @@ Notice:
 ### 3. `xdl_addr()`
 
 ```C
-int xdl_addr(void *addr, Dl_info *info, void **cache);
+typedef struct
+{
+    const char       *dli_fname;
+    void             *dli_fbase;
+    const char       *dli_sname;
+    void             *dli_saddr;
+    size_t            dli_ssize;
+    const ElfW(Phdr) *dlpi_phdr;
+    size_t            dlpi_phnum;
+} xdl_info;
+
+int xdl_addr(void *addr, xdl_info *info, void **cache);
 void xdl_addr_clean(void **cache);
 ```
 
-`xdl_addr()` is similar to `dladdr()`. But there are a few differences:
+`xdl_addr()` is similar to [`dladdr()`](https://man7.org/linux/man-pages/man3/dladdr.3.html). But there are a few differences:
 
 * `xdl_addr()` can lookup not only dynamic link symbols, but also debugging symbols. 
+* `xdl_addr()` uses the `xdl_info` structure instead of the `Dl_info` structure, which contains more extended information: `dli_ssize` is the number of bytes occupied by the current symbol; `dlpi_phdr` points to the program headers array of the ELF where the current symbol is located; `dlpi_phnum` is the number of elements in the `dlpi_phdr` array.
 * `xdl_addr()` needs to pass an additional parameter (`cache`), which will cache the ELF handle opened during the execution of `xdl_addr()`. The purpose of caching is to make subsequent executions of `xdl_addr()` of the same ELF faster. When you do not need to execute `xdl_addr()`, please use `xdl_addr_clean()` to clear the cache. For example:
 
 ```C
 void *cache = NULL;
-Dl_info info;
+xdl_info info;
 xdl_addr(addr_1, &info, &cache);
 xdl_addr(addr_2, &info, &cache);
 xdl_addr(addr_3, &info, &cache);
@@ -215,18 +227,16 @@ xdl_addr_clean(&cache);
 
 ```C
 #define XDL_DEFAULT       0x00
-#define XDL_WITH_LINKER   0x01
-#define XDL_FULL_PATHNAME 0x02
+#define XDL_FULL_PATHNAME 0x01
 
 int xdl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), void *data, int flags);
 ```
 
-`xdl_iterate_phdr()` is similar to `dl_iterate_phdr()`. But `xdl_iterate_phdr()` is compatible with android 4.x on ARM32.
+`xdl_iterate_phdr()` is similar to [`dl_iterate_phdr()`](https://man7.org/linux/man-pages/man3/dl_iterate_phdr.3.html). But `xdl_iterate_phdr()` is compatible with android 4.x on ARM32, and always including linker / linker64.
 
 `xdl_iterate_phdr()` has an additional "flags" parameter, one or more flags can be bitwise-or'd in it:
 
 * `XDL_DEFAULT`: Default behavior.
-* `XDL_WITH_LINKER`: Always including linker / linker64.
 * `XDL_FULL_PATHNAME`: Always return full pathname instead of basename.
 
 These flags are needed because these capabilities require additional execution time, and you don't always need them.

README.zh-CN.md

@@ -142,7 +142,7 @@ void *xdl_open(const char *filename, int flags);
 void *xdl_close(void *handle);
 ```
 
-它们和 `dlopen()` / `dlclose()` 很相似。但是 `xdl_open()` 可以绕过 Android 7.0+ linker namespace 的限制。
+它们和 [`dlopen()`](https://man7.org/linux/man-pages/man3/dlopen.3.html) / [`dlclose()`](https://man7.org/linux/man-pages/man3/dlclose.3.html) 很相似。但是 `xdl_open()` 可以绕过 Android 7.0+ linker namespace 的限制。
 
 根据 `flags` 参数值的不同，`xdl_open()` 的行为会有一些差异：
 
@@ -176,7 +176,7 @@ void *xdl_sym(void *handle, const char *symbol, size_t *symbol_size);
 void *xdl_dsym(void *handle, const char *symbol, size_t *symbol_size);
 ```
 
-它们和 `dlsym()` 很相似。 它们都需要传递一个 `xdl_open()` 返回的 “handle”，和一个 null 结尾的符号名字，返回该符号在内存中的加载地址。
+它们和 [`dlsym()`](https://man7.org/linux/man-pages/man3/dlsym.3.html) 很相似。 它们都需要传递一个 `xdl_open()` 返回的 “handle”，和一个 null 结尾的符号名字，返回该符号在内存中的加载地址。
 
 如果 `symbol_size` 参数不为 `NULL`，它将被赋值为“符号对应的内容在 ELF 中占用的字节数”，如果你不需要这个信息，传递 `NULL` 就可以了。
 
@@ -193,13 +193,25 @@ void *xdl_dsym(void *handle, const char *symbol, size_t *symbol_size);
 ### 3. `xdl_addr()`
 
 ```C
-int xdl_addr(void *addr, Dl_info *info, void **cache);
+typedef struct
+{
+    const char       *dli_fname;
+    void             *dli_fbase;
+    const char       *dli_sname;
+    void             *dli_saddr;
+    size_t            dli_ssize;
+    const ElfW(Phdr) *dlpi_phdr;
+    size_t            dlpi_phnum;
+} xdl_info;
+
+int xdl_addr(void *addr, xdl_info *info, void **cache);
 void xdl_addr_clean(void **cache);
 ```
 
-`xdl_addr()` 和 `dladdr()` 很相似。但有以下几点不同：
+`xdl_addr()` 和 [`dladdr()`](https://man7.org/linux/man-pages/man3/dladdr.3.html) 很相似。但有以下几点不同：
 
 * `xdl_addr()` 不仅能查询动态链接符号，还能查询调试符号。
+*  `xdl_addr()` 使用 `dl_info` 结构体代替了 `Dl_info` 结构体，它包含了更多的扩展信息：`dli_ssize` 是当前符号所占用的字节数；`dlpi_phdr` 指向当前符号所在 ELF 的 program headers 数组；`dlpi_phnum` 是 `dlpi_phdr` 数组的元素个数。
 * `xdl_addr()` 需要传递一个附加的参数（cache），其中会缓存 `xdl_addr()` 执行过程中打开的 ELF handle，缓存的目的是使后续对同一个 ELF 的 `xdl_addr()` 执行的更快。当不需要再执行 `xdl_addr()` 时，请使用 `xdl_addr_clean()` 清除缓存。举例：
 
 ```C
@@ -215,18 +227,16 @@ xdl_addr_clean(&cache);
 
 ```C
 #define XDL_DEFAULT       0x00
-#define XDL_WITH_LINKER   0x01
-#define XDL_FULL_PATHNAME 0x02
+#define XDL_FULL_PATHNAME 0x01
 
 int xdl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), void *data, int flags);
 ```
 
-`xdl_iterate_phdr()` 和 `dl_iterate_phdr()` 很相似。但是 `xdl_iterate_phdr()` 兼容 ARM32 平台的 Android 4.x 系统。
+`xdl_iterate_phdr()` 和 [`dl_iterate_phdr()`](https://man7.org/linux/man-pages/man3/dl_iterate_phdr.3.html) 很相似。但是 `xdl_iterate_phdr()` 兼容 ARM32 平台的 Android 4.x 系统，并且总是包含 linker / linker64。
 
 `xdl_iterate_phdr()` 有一个额外的“flags”参数，一个或多个“flag”可以按位“或”后传递给它:
 
 * `XDL_DEFAULT`: 默认行为。
-* `XDL_WITH_LINKER`: 总是包含 linker / linker64。
 * `XDL_FULL_PATHNAME`: 总是返回完整的路径名（full pathname），而不是文件名（basename）。
 
 需要这些 flags 的原因是，这些额外的能力也需要花费额外的执行时间，而你并不总是需要这些能力。