Add xdl_info().

Author: caikelun

README.md

@@ -2,7 +2,7 @@
 
 ![](https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat)
 ![](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat)
-![](https://img.shields.io/badge/release-1.1.5-red.svg?style=flat)
+![](https://img.shields.io/badge/release-1.2.0-red.svg?style=flat)
 ![](https://img.shields.io/badge/Android-4.1%20--%2013-blue.svg?style=flat)
 ![](https://img.shields.io/badge/arch-armeabi--v7a%20%7C%20arm64--v8a%20%7C%20x86%20%7C%20x86__64-blue.svg?style=flat)
 
@@ -61,7 +61,7 @@ android {
 }
 
 dependencies {
-    implementation 'io.hexhacking:xdl:1.1.5'
+    implementation 'io.hexhacking:xdl:1.2.0'
 }
 ```
 
@@ -202,21 +202,21 @@ typedef struct
     size_t            dli_ssize;
     const ElfW(Phdr) *dlpi_phdr;
     size_t            dlpi_phnum;
-} xdl_info;
+} xdl_info_t;
 
-int xdl_addr(void *addr, xdl_info *info, void **cache);
+int xdl_addr(void *addr, xdl_info_t *info, void **cache);
 void xdl_addr_clean(void **cache);
 ```
 
 `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()` uses the `xdl_info_t` 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;
-xdl_info info;
+xdl_info_t info;
 xdl_addr(addr_1, &info, &cache);
 xdl_addr(addr_2, &info, &cache);
 xdl_addr(addr_3, &info, &cache);
@@ -241,6 +241,19 @@ int xdl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), voi
 
 These flags are needed because these capabilities require additional execution time, and you don't always need them.
 
+### 5. `xdl_info()`
+
+```C
+#define XDL_DI_DLINFO 1  // type of info: xdl_info_t
+
+int xdl_info(void *handle, int request, void *info);
+```
+
+`xdl_info()` is similar to [`dlinfo()`](https://man7.org/linux/man-pages/man3/dl_iterate_phdr.3.html). `xdl_info()` obtains information about the dynamically loaded object referred to by `handle` (obtained by an earlier call to `xdl_open`).
+
+The only `request` parameter currently supported is `XDL_DI_DLINFO`, which means to return data of type `xdl_info_t` through the `info` parameter (note that the values of `dli_sname`, `dli_saddr`, `dli_ssize` in the returned `xdl_info_t` at this time both are `0`).
+
+On success, `xdl_info()` returns `0`.  On failure, it returns `-1`.
 
 ## Support
 

README.zh-CN.md

@@ -2,7 +2,7 @@
 
 ![](https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat)
 ![](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat)
-![](https://img.shields.io/badge/release-1.1.5-red.svg?style=flat)
+![](https://img.shields.io/badge/release-1.2.0-red.svg?style=flat)
 ![](https://img.shields.io/badge/Android-4.1%20--%2013-blue.svg?style=flat)
 ![](https://img.shields.io/badge/arch-armeabi--v7a%20%7C%20arm64--v8a%20%7C%20x86%20%7C%20x86__64-blue.svg?style=flat)
 
@@ -61,7 +61,7 @@ android {
 }
 
 dependencies {
-    implementation 'io.hexhacking:xdl:1.1.5'
+    implementation 'io.hexhacking:xdl:1.2.0'
 }
 ```
 
@@ -142,7 +142,7 @@ void *xdl_open(const char *filename, int flags);
 void *xdl_close(void *handle);
 ```
 
-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。
+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) 类似。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()`](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。
+它们和 [`dlsym()`](https://man7.org/linux/man-pages/man3/dlsym.3.html) 类似。 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。
 
@@ -202,21 +202,21 @@ typedef struct
     size_t            dli_ssize;
     const ElfW(Phdr) *dlpi_phdr;
     size_t            dlpi_phnum;
-} xdl_info;
+} xdl_info_t;
 
-int xdl_addr(void *addr, xdl_info *info, void **cache);
+int xdl_addr(void *addr, xdl_info_t *info, void **cache);
 void xdl_addr_clean(void **cache);
 ```
 
-`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()` 和 [`dladdr()`](https://man7.org/linux/man-pages/man3/dladdr.3.html) 类似。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()` 使用 `xdl_info_t` 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
 void *cache = NULL;
-Dl_info info;
+xdl_info_t info;
 xdl_addr(addr_1, &info, &cache);
 xdl_addr(addr_2, &info, &cache);
 xdl_addr(addr_3, &info, &cache);
@@ -232,7 +232,7 @@ xdl_addr_clean(&cache);
 int xdl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), void *data, int flags);
 ```
 
-`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()` 和 [`dl_iterate_phdr()`](https://man7.org/linux/man-pages/man3/dl_iterate_phdr.3.html) 类似。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:
 
@@ -241,6 +241,19 @@ int xdl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), voi
 
 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。
 
+### 5. `xdl_info()`
+
+```C
+#define XDL_DI_DLINFO 1  // type of info: xdl_info_t
+
+int xdl_info(void *handle, int request, void *info);
+```
+
+`xdl_info()` 和 [`dlinfo()`](https://man7.org/linux/man-pages/man3/dl_iterate_phdr.3.html) 类似。`xdl_info()` 通过 `handle`（`xdl_open` 的返回值）来获取动态加载对象的信息。
+
+目前唯一支持的 `request` 参数是 `XDL_DI_DLINFO`，表示通过 `info` 参数返回 `xdl_info_t` 类型的数据（注意，此时返回的 `xdl_info_t` 中 `dli_sname`、`dli_saddr`、`dli_ssize` 的值均为 `0`）。
+
+成功时 `xdl_info()` 返回 `0`，失败时返回 `-1`。
 
 ## 技术支持
 

build.gradle

@@ -21,7 +21,7 @@ ext {
 
     POM_GROUP_ID = "io.hexhacking"
     POM_ARTIFACT_ID = "xdl"
-    POM_VERSION_NAME = "1.1.5"
+    POM_VERSION_NAME = "1.2.0"
 
     POM_NAME = "xDL Android Lib"
     POM_DESCRIPTION = "xDL is an enhanced implementation of the Android DL series functions."

xdl/src/main/cpp/include/xdl.h

@@ -22,7 +22,7 @@
 // Created by caikelun on 2020-10-04.
 
 //
-// xDL version: 1.1.5
+// xDL version: 1.2.0
 //
 // xDL is an enhanced implementation of the Android DL series functions.
 // For more information, documentation, and the latest version please check:
@@ -40,6 +40,18 @@
 extern "C" {
 #endif
 
+typedef struct {
+  // same as Dl_info:
+  const char *dli_fname;  // Pathname of shared object that contains address.
+  void *dli_fbase;        // Address at which shared object is loaded.
+  const char *dli_sname;  // Name of nearest symbol with address lower than addr.
+  void *dli_saddr;        // Exact address of symbol named in dli_sname.
+  // added by xDL:
+  size_t dli_ssize;             // Symbol size of nearest symbol with address lower than addr.
+  const ElfW(Phdr) *dlpi_phdr;  // Pointer to array of ELF program headers for this object.
+  size_t dlpi_phnum;            // Number of items in dlpi_phdr.
+} xdl_info_t;
+
 //
 // Default value for flags in both xdl_open() and xdl_iterate_phdr().
 //
@@ -58,18 +70,7 @@ void *xdl_dsym(void *handle, const char *symbol, size_t *symbol_size);
 //
 // Enhanced dladdr().
 //
-typedef struct {
-  // same as Dl_info:
-  const char *dli_fname;  // Pathname of shared object that contains address.
-  void *dli_fbase;        // Address at which shared object is loaded.
-  const char *dli_sname;  // Name of nearest symbol with address lower than addr.
-  void *dli_saddr;        // Exact address of symbol named in dli_sname.
-  // added by xDL:
-  size_t dli_ssize;             // Symbol size of nearest symbol with address lower than addr.
-  const ElfW(Phdr) *dlpi_phdr;  // Pointer to array of ELF program headers for this object.
-  size_t dlpi_phnum;            // Number of items in dlpi_phdr.
-} xdl_info;
-int xdl_addr(void *addr, xdl_info *info, void **cache);
+int xdl_addr(void *addr, xdl_info_t *info, void **cache);
 void xdl_addr_clean(void **cache);
 
 //
@@ -78,6 +79,12 @@ void xdl_addr_clean(void **cache);
 #define XDL_FULL_PATHNAME 0x01
 int xdl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), void *data, int flags);
 
+//
+// Custom dlinfo().
+//
+#define XDL_DI_DLINFO 1  // type of info: xdl_info_t
+int xdl_info(void *handle, int request, void *info);
+
 #ifdef __cplusplus
 }
 #endif

xdl/src/main/cpp/xdl.c

@@ -792,7 +792,7 @@ static ElfW(Sym) *xdl_dsym_by_addr(void *handle, void *addr) {
   return NULL;
 }
 
-int xdl_addr(void *addr, xdl_info *info, void **cache) {
+int xdl_addr(void *addr, xdl_info_t *info, void **cache) {
   if (NULL == addr || NULL == info || NULL == cache) return 0;
 
   memset(info, 0, sizeof(Dl_info));
@@ -851,3 +851,19 @@ int xdl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), voi
 
   return xdl_iterate_phdr_impl(callback, data, flags);
 }
+
+int xdl_info(void *handle, int request, void *info) {
+  if (NULL == handle || XDL_DI_DLINFO != request || NULL == info) return -1;
+
+  xdl_t *self = (xdl_t *)handle;
+  xdl_info_t *dlinfo = (xdl_info_t *)info;
+
+  dlinfo->dli_fbase = (void *)self->load_bias;
+  dlinfo->dli_fname = self->pathname;
+  dlinfo->dli_sname = NULL;
+  dlinfo->dli_saddr = 0;
+  dlinfo->dli_ssize = 0;
+  dlinfo->dlpi_phdr = self->dlpi_phdr;
+  dlinfo->dlpi_phnum = (size_t)self->dlpi_phnum;
+  return 0;
+}

xdl/src/main/cpp/xdl.map.txt

@@ -7,6 +7,7 @@
         xdl_addr;
         xdl_addr_clean;
         xdl_iterate_phdr;
+        xdl_info;
 
     local:
         *;

xdl_sample/build.gradle

@@ -66,7 +66,7 @@ dependencies {
     if (rootProject.ext.dependencyOnLocalLibrary) {
         implementation project(':xdl')
     } else {
-        implementation 'io.hexhacking:xdl:1.1.5'
+        implementation 'io.hexhacking:xdl:1.2.0'
     }
 }
 

xdl_sample/src/main/cpp/sample.c

@@ -65,18 +65,27 @@ static void sample_test_iterate(void) {
 
 static void *sample_test_dlsym(const char *filename, const char *symbol, bool debug_symbol, void **cache,
                                bool try_force_dlopen) {
+  xdl_info_t info;
+
   if (try_force_dlopen) {
     void *linker_handle = dlopen(filename, RTLD_NOW);
     LOG("--- dlopen(%s) : handle %" PRIxPTR, filename, (uintptr_t)linker_handle);
     if (NULL != linker_handle) dlclose(linker_handle);
   }
 
-  LOG("+++ xdl_open + %s + xdl_addr", debug_symbol ? "xdl_dsym" : "xdl_sym");
+  LOG("+++ xdl_open + xdl_info + %s + xdl_addr", debug_symbol ? "xdl_dsym" : "xdl_sym");
 
   // xdl_open
   void *handle = xdl_open(filename, try_force_dlopen ? XDL_TRY_FORCE_LOAD : XDL_DEFAULT);
   LOG(">>> xdl_open(%s) : handle %" PRIxPTR, filename, (uintptr_t)handle);
 
+  // xdl_info
+  memset(&info, 0, sizeof(xdl_info_t));
+  xdl_info(handle, XDL_DI_DLINFO, &info);
+  LOG(">>> xdl_info(%" PRIxPTR ") : %" PRIxPTR " %s (phdr %" PRIxPTR ", phnum %zu)", (uintptr_t)handle,
+      (uintptr_t)info.dli_fbase, (NULL == info.dli_fname ? "(NULL)" : info.dli_fname),
+      (uintptr_t)info.dlpi_phdr, info.dlpi_phnum);
+
   // xdl_dsym / xdl_sym
   size_t symbol_size = 0;
   void *symbol_addr = (debug_symbol ? xdl_dsym : xdl_sym)(handle, symbol, &symbol_size);
@@ -87,7 +96,7 @@ static void *sample_test_dlsym(const char *filename, const char *symbol, bool de
   void *linker_handle = xdl_close(handle);
 
   // xdl_addr
-  xdl_info info;
+  memset(&info, 0, sizeof(xdl_info_t));
   if (0 == xdl_addr(symbol_addr, &info, cache))
     LOG(">>> xdl_addr(%" PRIxPTR ") : FAILED", (uintptr_t)symbol_addr);
   else