Add support for uClibc

uClibc doesn't implement the dlinfo() and dladdr1() dl functions.
The existing Android solution fits for the uClibc case as well.

plthook_elf.c

@@ -62,6 +62,10 @@
 #include <link.h>
 #include "plthook.h"
 
+#if defined __UCLIBC__ && !defined RTLD_NOLOAD
+#define RTLD_NOLOAD 0
+#endif
+
 #ifndef __GNUC__
 #define __attribute__(arg)
 #endif
@@ -200,7 +204,7 @@ static int check_elf_header(const Elf_Ehdr *ehdr);
 #endif
 static void set_errmsg(const char *fmt, ...) __attribute__((__format__ (__printf__, 1, 2)));
 
-#if defined __ANDROID__
+#if defined __ANDROID__ || defined __UCLIBC__
 struct dl_iterate_data {
     char* addr;
     struct link_map lmap;
@@ -245,7 +249,7 @@ int plthook_open(plthook_t **plthook_out, const char *filename)
 
 int plthook_open_by_handle(plthook_t **plthook_out, void *hndl)
 {
-#if defined __ANDROID__
+#if defined __ANDROID__ || defined __UCLIBC__
     char *addr;
 
     if (hndl == NULL) {
@@ -276,7 +280,7 @@ int plthook_open_by_address(plthook_t **plthook_out, void *address)
 {
 #if defined __FreeBSD__
     return PLTHOOK_NOT_IMPLEMENTED;
-#elif defined __ANDROID__
+#elif defined __ANDROID__ || defined __UCLIBC__
     struct dl_iterate_data data = {0,};
     data.addr = address;
     dl_iterate_phdr(dl_iterate_cb, &data);
@@ -300,7 +304,7 @@ int plthook_open_by_address(plthook_t **plthook_out, void *address)
 
 static int plthook_open_executable(plthook_t **plthook_out)
 {
-#if defined __ANDROID__
+#if defined __ANDROID__ || defined __UCLIBC__
     return plthook_open_shared_library(plthook_out, NULL);
 #elif defined __linux__
     return plthook_open_real(plthook_out, _r_debug.r_map);
@@ -339,7 +343,7 @@ static int plthook_open_executable(plthook_t **plthook_out)
 static int plthook_open_shared_library(plthook_t **plthook_out, const char *filename)
 {
     void *hndl = dlopen(filename, RTLD_LAZY | RTLD_NOLOAD);
-#ifdef __ANDROID__
+#if defined __ANDROID__ || defined __UCLIBC__
     int rv;
 #else
     struct link_map *lmap = NULL;
@@ -349,7 +353,7 @@ static int plthook_open_shared_library(plthook_t **plthook_out, const char *file
         set_errmsg("dlopen error: %s", dlerror());
         return PLTHOOK_FILE_NOT_FOUND;
     }
-#ifdef __ANDROID__
+#if defined __ANDROID__ || defined __UCLIBC__
     rv = plthook_open_by_handle(plthook_out, hndl);
     dlclose(hndl);
     return rv;
@@ -541,7 +545,7 @@ static int plthook_open_real(plthook_t **plthook_out, struct link_map *lmap)
 
 #if defined __linux__
     plthook.plt_addr_base = (char*)lmap->l_addr;
-#if defined __ANDROID__
+#if defined __ANDROID__ || defined __UCLIBC__
     dyn_addr_base = (const char*)lmap->l_addr;
 #endif
 #elif defined __FreeBSD__ || defined __sun

test/testprog.c

@@ -1,4 +1,5 @@
 #include <plthook.h>
+#include <features.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
@@ -10,6 +11,10 @@
 #include <dlfcn.h>
 #endif
 
+#if defined __UCLIBC__ && !defined RTLD_NOLOAD
+#define RTLD_NOLOAD 0
+#endif
+
 #define CHK_PH(func) do { \
     if (func != 0) { \
         fprintf(stderr, "%s error: %s\n", #func, plthook_error()); \