android/main-emulator.c - platform/external/qemu - Git at Google

 /* Copyright (C) 2011 The Android Open Source Project
 **
 ** This software is licensed under the terms of the GNU General Public
 ** License version 2, as published by the Free Software Foundation, and
 ** may be copied, distributed, and modified under those terms.
 **
 ** This program is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 ** GNU General Public License for more details.
 */

 /* This is the source code to the tiny "emulator" launcher program
  * that is in charge of starting the target-specific emulator binary
  * for a given AVD, i.e. either 'emulator-arm' or 'emulator-x86'
  *
  * This program will be replaced in the future by what is currently
  * known as 'emulator-ui', but is a good placeholder until this
  * migration is completed.
  */

 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <android/utils/panic.h>
 #include <android/utils/path.h>
 #include <android/utils/bufprint.h>
 #include <android/avd/util.h>

 /* Required by android/utils/debug.h */
 int android_verbose;


 #define DEBUG 1

 #if DEBUG
 #  define D(...)  do { if (android_verbose) printf("emulator:" __VA_ARGS__); } while (0)
 #else
 #  define D(...)  do{}while(0)
 #endif

 /* The extension used by dynamic libraries on the host platform */
 #ifdef _WIN32
 #  define DLL_EXTENSION  ".dll"
 #elif defined(__APPLE__)
 #  define DLL_EXTENSION  ".dylib"
 #else
 #  define DLL_EXTENSION  ".so"
 #endif

 #if defined(__x86_64__)
 /* Normally emulator is compiled in 32-bit.  In standalone it can be compiled
    in 64-bit (with ,/android-configure.sh --try-64).  In this case, emulator-$ARCH
    are also compiled in 64-bit and will search for lib64*.so instead of lib*so */
 #define  GLES_EMULATION_LIB  "lib64OpenglRender" DLL_EXTENSION
 #elif defined(__i386__)
 #define  GLES_EMULATION_LIB  "libOpenglRender" DLL_EXTENSION
 #else
 #error Unknown architecture for codegen
 #endif


 /* Forward declarations */
 static char* getTargetEmulatorPath(const char* progName, const char* avdArch, const int force_32bit);
 static char* getSharedLibraryPath(const char* progName, const char* libName);
 static void  prependSharedLibraryPath(const char* prefix);

 #ifdef _WIN32
 static char* quotePath(const char* path);
 #endif

 /* The execv() definition in mingw is slightly bogus.
  * It takes a second argument of type 'const char* const*'
  * while POSIX mandates char** instead.
  *
  * To avoid compiler warnings, define the safe_execv macro
  * to perform an explicit cast with mingw.
  */
 #ifdef _WIN32
 #  define safe_execv(_filepath,_argv)  execv((_filepath),(const char* const*)(_argv))
 #else
 #  define safe_execv(_filepath,_argv)  execv((_filepath),(_argv))
 #endif

 /* Main routine */
 int main(int argc, char** argv)
 {
     const char* avdName = NULL;
     char*       avdArch = NULL;
     char*       emulatorPath;
     int         force_32bit = 0;

     /* Define ANDROID_EMULATOR_DEBUG to 1 in your environment if you want to
      * see the debug messages from this launcher program.
      */
     const char* debug = getenv("ANDROID_EMULATOR_DEBUG");

     if (debug != NULL && *debug && *debug != '0')
         android_verbose = 1;

     /* Parse command-line and look for
      * 1) an avd name either in the form or '-avd <name>' or '@<name>'
      * 2) '-force-32bit' which always use 32-bit emulator on 64-bit platforms
      */
     int  nn;
     for (nn = 1; nn < argc; nn++) {
         const char* opt = argv[nn];

         if (!strcmp(opt,"-qemu"))
             break;

         if (!strcmp(opt,"-force-32bit")) {
             force_32bit = 1;
             continue;
         }

         if (!avdName) {
             if (!strcmp(opt,"-avd") && nn+1 < argc) {
                 avdName = argv[nn+1];
             }
             else if (opt[0] == '@' && opt[1] != '\0') {
                 avdName = opt+1;
             }
         }
     }

     /* If there is an AVD name, we're going to extract its target architecture
      * by looking at its config.ini
      */
     if (avdName != NULL) {
         D("Found AVD name '%s'\n", avdName);
         avdArch = path_getAvdTargetArch(avdName);
         D("Found AVD target architecture: %s\n", avdArch);
     } else {
         /* Otherwise, using the ANDROID_PRODUCT_OUT directory */
         const char* androidOut = getenv("ANDROID_PRODUCT_OUT");

         if (androidOut != NULL && *androidOut != '\0') {
             D("Found ANDROID_PRODUCT_OUT: %s\n", androidOut);
             avdArch = path_getBuildTargetArch(androidOut);
             D("Found build target architecture: %s\n", avdArch);
         }
     }

     if (avdArch == NULL) {
         avdArch = "arm";
         D("Can't determine target AVD architecture: defaulting to %s\n", avdArch);
     }
     if (!strcmp(avdArch, "mips"))
         force_32bit = 1;   /* emulator64-mips segfaults currently, 4-19-2012 */

     /* Find the architecture-specific program in the same directory */
     emulatorPath = getTargetEmulatorPath(argv[0], avdArch, force_32bit);
     D("Found target-specific emulator binary: %s\n", emulatorPath);

     /* Replace it in our command-line */
     argv[0] = emulatorPath;

 #ifdef _WIN32
     /* Looks like execv() in mingw (or is it MSVCRT.DLL?) doesn't
      * support a space in argv[0] unless we explicitely quote it.
      * IMPORTANT: do not quote the first argument to execv() or it will fail.
      * This was tested on a 32-bit Vista installation.
      */
     if (strchr(emulatorPath, ' ')) {
         argv[0] = quotePath(emulatorPath);
         D("Quoted emulator binary path: %s\n", emulatorPath);
     }
 #endif

     /* We need to find the location of the GLES emulation shared libraries
      * and modify either LD_LIBRARY_PATH or PATH accordingly
      */
     {
         char*  sharedLibPath = getSharedLibraryPath(emulatorPath, GLES_EMULATION_LIB);

         if (sharedLibPath != NULL) {
             D("Found OpenGLES emulation libraries in %s\n", sharedLibPath);
             prependSharedLibraryPath(sharedLibPath);
         } else {
             D("Could not find OpenGLES emulation host libraries!\n");
         }
     }

     /* Launch it with the same set of options ! */
     safe_execv(emulatorPath, argv);

     /* We could not launch the program ! */
     fprintf(stderr, "Could not launch '%s': %s\n", emulatorPath, strerror(errno));
     return errno;
 }

 static int
 getHostOSBitness()
 {
   /*
      This function returns 64 if host is running 64-bit OS, or 32 otherwise.

      It uses the same technique in ndk/build/core/ndk-common.sh.
      Here are comments from there:

   ## On Linux or Darwin, a 64-bit kernel (*) doesn't mean that the user-land
   ## is always 32-bit, so use "file" to determine the bitness of the shell
   ## that invoked us. The -L option is used to de-reference symlinks.
   ##
   ## Note that on Darwin, a single executable can contain both x86 and
   ## x86_64 machine code, so just look for x86_64 (darwin) or x86-64 (Linux)
   ## in the output.

     (*) ie. The following code doesn't always work:
         struct utsname u;
         int host_runs_64bit_OS = (uname(&u) == 0 && strcmp(u.machine, "x86_64") == 0);
   */
     return system("file -L \"$SHELL\" | grep -q \"x86[_-]64\"") == 0 ? 64 : 32;
 }

 /* Find the target-specific emulator binary. This will be something
  * like  <programDir>/emulator-<targetArch>, where <programDir> is
  * the directory of the current program.
  */
 static char*
 getTargetEmulatorPath(const char* progName, const char* avdArch, const int force_32bit)
 {
     char*  progDir;
     char   path[PATH_MAX], *pathEnd=path+sizeof(path), *p;
     const char* emulatorPrefix = "emulator-";
     const char* emulator64Prefix = "emulator64-";
 #ifdef _WIN32
     const char* exeExt = ".exe";
     /* ToDo: currently amd64-mingw32msvc-gcc doesn't work (http://b/issue?id=5949152)
              which prevents us from generating 64-bit emulator for Windows */
     int search_for_64bit_emulator = 0;
 #else
     const char* exeExt = "";
     int search_for_64bit_emulator = !force_32bit && getHostOSBitness() == 64;
 #endif

     /* Get program's directory name in progDir */
     path_split(progName, &progDir, NULL);

     if (search_for_64bit_emulator) {
         /* Find 64-bit emulator first */
         p = bufprint(path, pathEnd, "%s/%s%s%s", progDir, emulator64Prefix, avdArch, exeExt);
         if (p >= pathEnd) {
             APANIC("Path too long: %s\n", progName);
         }
         if (path_exists(path)) {
             free(progDir);
             return strdup(path);
         }
     }

     /* Find 32-bit emulator */
     p = bufprint(path, pathEnd, "%s/%s%s%s", progDir, emulatorPrefix, avdArch, exeExt);
     free(progDir);
     if (p >= pathEnd) {
         APANIC("Path too long: %s\n", progName);
     }

     if (path_exists(path)) {
         return strdup(path);
     }

     /* Mmm, the file doesn't exist, If there is no slash / backslash
      * in our path, we're going to try to search it in our path.
      */
 #ifdef _WIN32
     if (strchr(progName, '/') == NULL && strchr(progName, '\\') == NULL) {
 #else
     if (strchr(progName, '/') == NULL) {
 #endif
         if (search_for_64bit_emulator) {
            p = bufprint(path, pathEnd, "%s%s%s", emulator64Prefix, avdArch, exeExt);
            if (p < pathEnd) {
                char*  resolved = path_search_exec(path);
                if (resolved != NULL)
                    return resolved;
            }
         }

         p = bufprint(path, pathEnd, "%s%s%s", emulatorPrefix, avdArch, exeExt);
         if (p < pathEnd) {
             char*  resolved = path_search_exec(path);
             if (resolved != NULL)
                 return resolved;
         }
     }

     /* Otherwise, the program is missing */
     APANIC("Missing arch-specific emulator program: %s\n", path);
     return NULL;
 }

 /* return 1 iff <path>/<filename> exists */
 static int
 probePathForFile(const char* path, const char* filename)
 {
     char  temp[PATH_MAX], *p=temp, *end=p+sizeof(temp);
     p = bufprint(temp, end, "%s/%s", path, filename);
     D("Probing for: %s\n", temp);
     return (p < end && path_exists(temp));
 }

 /* Find the directory containing a given shared library required by the
  * emulator (for GLES emulation). We will probe several directories
  * that correspond to various use-cases.
  *
  * Caller must free() result string. NULL if not found.
  */

 static char*
 getSharedLibraryPath(const char* progName, const char* libName)
 {
     char* progDir;
     char* result = NULL;
     char  temp[PATH_MAX], *p=temp, *end=p+sizeof(temp);

     /* Get program's directory name */
     path_split(progName, &progDir, NULL);

     /* First, try to probe the program's directory itself, this corresponds
      * to the standalone build with ./android-configure.sh where the script
      * will copy the host shared library under external/qemu/objs where
      * the binaries are located.
      */
     if (probePathForFile(progDir, libName)) {
         return progDir;
     }

     /* Try under $progDir/lib/, this should correspond to the SDK installation
      * where the binary is under tools/, and the libraries under tools/lib/
      */
     {
         p = bufprint(temp, end, "%s/lib", progDir);
         if (p < end && probePathForFile(temp, libName)) {
             result = strdup(temp);
             goto EXIT;
         }
     }

     /* try in $progDir/../lib, this corresponds to the platform build
      * where the emulator binary is under out/host/<system>/bin and
      * the libraries are under out/host/<system>/lib
      */
     {
         char* parentDir = path_parent(progDir, 1);

         if (parentDir == NULL) {
             parentDir = strdup(".");
         }
         p = bufprint(temp, end, "%s/lib", parentDir);
         free(parentDir);
         if (p < end && probePathForFile(temp, libName)) {
             result = strdup(temp);
             goto EXIT;
         }
     }

     /* Nothing found! */
 EXIT:
     free(progDir);
     return result;
 }

 /* Prepend the path in 'prefix' to either LD_LIBRARY_PATH or PATH to
  * ensure that the shared libraries inside the path will be available
  * through dlopen() to the emulator program being launched.
  */
 static void
 prependSharedLibraryPath(const char* prefix)
 {
     char temp[2048], *p=temp, *end=p+sizeof(temp);
 #ifdef _WIN32
     const char* path = getenv("PATH");
     if (path == NULL || path[0] == '\0') {
         p = bufprint(temp, end, "PATH=%s", prefix);
     } else {
         p = bufprint(temp, end, "PATH=%s;%s", path, prefix);
     }
     /* Ignore overflow, this will push some paths out of the variable, but
      * so be it. */
     D("Setting %s\n", temp);
     putenv(strdup(temp));
 #else
     const char* path = getenv("LD_LIBRARY_PATH");
     if (path != NULL && path[0] != '\0') {
         p = bufprint(temp, end, "%s:%s", prefix, path);
         prefix = temp;
     }
     setenv("LD_LIBRARY_PATH",prefix,1);
     D("Setting LD_LIBRARY_PATH=%s\n", prefix);
 #endif
 }

 #ifdef _WIN32
 static char*
 quotePath(const char* path)
 {
     int   len = strlen(path);
     char* ret = malloc(len+3);

     ret[0] = '"';
     memcpy(ret+1, path, len);
     ret[len+1] = '"';
     ret[len+2] = '\0';

     return ret;
 }
 #endif /* _WIN32 */
	/* Copyright (C) 2011 The Android Open Source Project
	**
	** This software is licensed under the terms of the GNU General Public
	** License version 2, as published by the Free Software Foundation, and
	** may be copied, distributed, and modified under those terms.
	**
	** This program is distributed in the hope that it will be useful,
	** but WITHOUT ANY WARRANTY; without even the implied warranty of
	** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	** GNU General Public License for more details.
	*/

	/* This is the source code to the tiny "emulator" launcher program
	* that is in charge of starting the target-specific emulator binary
	* for a given AVD, i.e. either 'emulator-arm' or 'emulator-x86'
	*
	* This program will be replaced in the future by what is currently
	* known as 'emulator-ui', but is a good placeholder until this
	* migration is completed.
	*/

	#include <errno.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>
	#include <android/utils/panic.h>
	#include <android/utils/path.h>
	#include <android/utils/bufprint.h>
	#include <android/avd/util.h>

	/* Required by android/utils/debug.h */
	int android_verbose;


	#define DEBUG 1

	#if DEBUG
	# define D(...) do { if (android_verbose) printf("emulator:" __VA_ARGS__); } while (0)
	#else
	# define D(...) do{}while(0)
	#endif

	/* The extension used by dynamic libraries on the host platform */
	#ifdef _WIN32
	# define DLL_EXTENSION ".dll"
	#elif defined(__APPLE__)
	# define DLL_EXTENSION ".dylib"
	#else
	# define DLL_EXTENSION ".so"
	#endif

	#if defined(__x86_64__)
	/* Normally emulator is compiled in 32-bit. In standalone it can be compiled
	in 64-bit (with ,/android-configure.sh --try-64). In this case, emulator-$ARCH
	are also compiled in 64-bit and will search for lib64.so instead of libso */
	#define GLES_EMULATION_LIB "lib64OpenglRender" DLL_EXTENSION
	#elif defined(__i386__)
	#define GLES_EMULATION_LIB "libOpenglRender" DLL_EXTENSION
	#else
	#error Unknown architecture for codegen
	#endif


	/* Forward declarations */
	static char* getTargetEmulatorPath(const char* progName, const char* avdArch, const int force_32bit);
	static char* getSharedLibraryPath(const char* progName, const char* libName);
	static void prependSharedLibraryPath(const char* prefix);

	#ifdef _WIN32
	static char* quotePath(const char* path);
	#endif

	/* The execv() definition in mingw is slightly bogus.
	* It takes a second argument of type 'const char* const*'
	* while POSIX mandates char** instead.
	*
	* To avoid compiler warnings, define the safe_execv macro
	* to perform an explicit cast with mingw.
	*/
	#ifdef _WIN32
	# define safe_execv(_filepath,_argv) execv((_filepath),(const char* const*)(_argv))
	#else
	# define safe_execv(_filepath,_argv) execv((_filepath),(_argv))
	#endif

	/* Main routine */
	int main(int argc, char** argv)
	{
	const char* avdName = NULL;
	char* avdArch = NULL;
	char* emulatorPath;
	int force_32bit = 0;

	/* Define ANDROID_EMULATOR_DEBUG to 1 in your environment if you want to
	* see the debug messages from this launcher program.
	*/
	const char* debug = getenv("ANDROID_EMULATOR_DEBUG");

	if (debug != NULL && debug && debug != '0')
	android_verbose = 1;

	/* Parse command-line and look for
	* 1) an avd name either in the form or '-avd <name>' or '@<name>'
	* 2) '-force-32bit' which always use 32-bit emulator on 64-bit platforms
	*/
	int nn;
	for (nn = 1; nn < argc; nn++) {
	const char* opt = argv[nn];

	if (!strcmp(opt,"-qemu"))
	break;

	if (!strcmp(opt,"-force-32bit")) {
	force_32bit = 1;
	continue;
	}

	if (!avdName) {
	if (!strcmp(opt,"-avd") && nn+1 < argc) {
	avdName = argv[nn+1];
	}
	else if (opt[0] == '@' && opt[1] != '\0') {
	avdName = opt+1;
	}
	}
	}

	/* If there is an AVD name, we're going to extract its target architecture
	* by looking at its config.ini
	*/
	if (avdName != NULL) {
	D("Found AVD name '%s'\n", avdName);
	avdArch = path_getAvdTargetArch(avdName);
	D("Found AVD target architecture: %s\n", avdArch);
	} else {
	/* Otherwise, using the ANDROID_PRODUCT_OUT directory */
	const char* androidOut = getenv("ANDROID_PRODUCT_OUT");

	if (androidOut != NULL && *androidOut != '\0') {
	D("Found ANDROID_PRODUCT_OUT: %s\n", androidOut);
	avdArch = path_getBuildTargetArch(androidOut);
	D("Found build target architecture: %s\n", avdArch);
	}
	}

	if (avdArch == NULL) {
	avdArch = "arm";
	D("Can't determine target AVD architecture: defaulting to %s\n", avdArch);
	}
	if (!strcmp(avdArch, "mips"))
	force_32bit = 1; /* emulator64-mips segfaults currently, 4-19-2012 */

	/* Find the architecture-specific program in the same directory */
	emulatorPath = getTargetEmulatorPath(argv[0], avdArch, force_32bit);
	D("Found target-specific emulator binary: %s\n", emulatorPath);

	/* Replace it in our command-line */
	argv[0] = emulatorPath;

	#ifdef _WIN32
	/* Looks like execv() in mingw (or is it MSVCRT.DLL?) doesn't
	* support a space in argv[0] unless we explicitely quote it.
	* IMPORTANT: do not quote the first argument to execv() or it will fail.
	* This was tested on a 32-bit Vista installation.
	*/
	if (strchr(emulatorPath, ' ')) {
	argv[0] = quotePath(emulatorPath);
	D("Quoted emulator binary path: %s\n", emulatorPath);
	}
	#endif

	/* We need to find the location of the GLES emulation shared libraries
	* and modify either LD_LIBRARY_PATH or PATH accordingly
	*/
	{
	char* sharedLibPath = getSharedLibraryPath(emulatorPath, GLES_EMULATION_LIB);

	if (sharedLibPath != NULL) {
	D("Found OpenGLES emulation libraries in %s\n", sharedLibPath);
	prependSharedLibraryPath(sharedLibPath);
	} else {
	D("Could not find OpenGLES emulation host libraries!\n");
	}
	}

	/* Launch it with the same set of options ! */
	safe_execv(emulatorPath, argv);

	/* We could not launch the program ! */
	fprintf(stderr, "Could not launch '%s': %s\n", emulatorPath, strerror(errno));
	return errno;
	}

	static int
	getHostOSBitness()
	{
	/*
	This function returns 64 if host is running 64-bit OS, or 32 otherwise.

	It uses the same technique in ndk/build/core/ndk-common.sh.
	Here are comments from there:

	## On Linux or Darwin, a 64-bit kernel (*) doesn't mean that the user-land
	## is always 32-bit, so use "file" to determine the bitness of the shell
	## that invoked us. The -L option is used to de-reference symlinks.
	##
	## Note that on Darwin, a single executable can contain both x86 and
	## x86_64 machine code, so just look for x86_64 (darwin) or x86-64 (Linux)
	## in the output.

	(*) ie. The following code doesn't always work:
	struct utsname u;
	int host_runs_64bit_OS = (uname(&u) == 0 && strcmp(u.machine, "x86_64") == 0);
	*/
	return system("file -L \"$SHELL\" \| grep -q \"x86[_-]64\"") == 0 ? 64 : 32;
	}

	/* Find the target-specific emulator binary. This will be something
	* like <programDir>/emulator-<targetArch>, where <programDir> is
	* the directory of the current program.
	*/
	static char*
	getTargetEmulatorPath(const char* progName, const char* avdArch, const int force_32bit)
	{
	char* progDir;
	char path[PATH_MAX], pathEnd=path+sizeof(path), p;
	const char* emulatorPrefix = "emulator-";
	const char* emulator64Prefix = "emulator64-";
	#ifdef _WIN32
	const char* exeExt = ".exe";
	/* ToDo: currently amd64-mingw32msvc-gcc doesn't work (http://b/issue?id=5949152)
	which prevents us from generating 64-bit emulator for Windows */
	int search_for_64bit_emulator = 0;
	#else
	const char* exeExt = "";
	int search_for_64bit_emulator = !force_32bit && getHostOSBitness() == 64;
	#endif

	/* Get program's directory name in progDir */
	path_split(progName, &progDir, NULL);

	if (search_for_64bit_emulator) {
	/* Find 64-bit emulator first */
	p = bufprint(path, pathEnd, "%s/%s%s%s", progDir, emulator64Prefix, avdArch, exeExt);
	if (p >= pathEnd) {
	APANIC("Path too long: %s\n", progName);
	}
	if (path_exists(path)) {
	free(progDir);
	return strdup(path);
	}
	}

	/* Find 32-bit emulator */
	p = bufprint(path, pathEnd, "%s/%s%s%s", progDir, emulatorPrefix, avdArch, exeExt);
	free(progDir);
	if (p >= pathEnd) {
	APANIC("Path too long: %s\n", progName);
	}

	if (path_exists(path)) {
	return strdup(path);
	}

	/* Mmm, the file doesn't exist, If there is no slash / backslash
	* in our path, we're going to try to search it in our path.
	*/
	#ifdef _WIN32
	if (strchr(progName, '/') == NULL && strchr(progName, '\\') == NULL) {
	#else
	if (strchr(progName, '/') == NULL) {
	#endif
	if (search_for_64bit_emulator) {
	p = bufprint(path, pathEnd, "%s%s%s", emulator64Prefix, avdArch, exeExt);
	if (p < pathEnd) {
	char* resolved = path_search_exec(path);
	if (resolved != NULL)
	return resolved;
	}
	}

	p = bufprint(path, pathEnd, "%s%s%s", emulatorPrefix, avdArch, exeExt);
	if (p < pathEnd) {
	char* resolved = path_search_exec(path);
	if (resolved != NULL)
	return resolved;
	}
	}

	/* Otherwise, the program is missing */
	APANIC("Missing arch-specific emulator program: %s\n", path);
	return NULL;
	}

	/* return 1 iff <path>/<filename> exists */
	static int
	probePathForFile(const char* path, const char* filename)
	{
	char temp[PATH_MAX], p=temp, end=p+sizeof(temp);
	p = bufprint(temp, end, "%s/%s", path, filename);
	D("Probing for: %s\n", temp);
	return (p < end && path_exists(temp));
	}

	/* Find the directory containing a given shared library required by the
	* emulator (for GLES emulation). We will probe several directories
	* that correspond to various use-cases.
	*
	* Caller must free() result string. NULL if not found.
	*/

	static char*
	getSharedLibraryPath(const char* progName, const char* libName)
	{
	char* progDir;
	char* result = NULL;
	char temp[PATH_MAX], p=temp, end=p+sizeof(temp);

	/* Get program's directory name */
	path_split(progName, &progDir, NULL);

	/* First, try to probe the program's directory itself, this corresponds
	* to the standalone build with ./android-configure.sh where the script
	* will copy the host shared library under external/qemu/objs where
	* the binaries are located.
	*/
	if (probePathForFile(progDir, libName)) {
	return progDir;
	}

	/* Try under $progDir/lib/, this should correspond to the SDK installation
	* where the binary is under tools/, and the libraries under tools/lib/
	*/
	{
	p = bufprint(temp, end, "%s/lib", progDir);
	if (p < end && probePathForFile(temp, libName)) {
	result = strdup(temp);
	goto EXIT;
	}
	}

	/* try in $progDir/../lib, this corresponds to the platform build
	* where the emulator binary is under out/host/<system>/bin and
	* the libraries are under out/host/<system>/lib
	*/
	{
	char* parentDir = path_parent(progDir, 1);

	if (parentDir == NULL) {
	parentDir = strdup(".");
	}
	p = bufprint(temp, end, "%s/lib", parentDir);
	free(parentDir);
	if (p < end && probePathForFile(temp, libName)) {
	result = strdup(temp);
	goto EXIT;
	}
	}

	/* Nothing found! */
	EXIT:
	free(progDir);
	return result;
	}

	/* Prepend the path in 'prefix' to either LD_LIBRARY_PATH or PATH to
	* ensure that the shared libraries inside the path will be available
	* through dlopen() to the emulator program being launched.
	*/
	static void
	prependSharedLibraryPath(const char* prefix)
	{
	char temp[2048], p=temp, end=p+sizeof(temp);
	#ifdef _WIN32
	const char* path = getenv("PATH");
	if (path == NULL \|\| path[0] == '\0') {
	p = bufprint(temp, end, "PATH=%s", prefix);
	} else {
	p = bufprint(temp, end, "PATH=%s;%s", path, prefix);
	}
	/* Ignore overflow, this will push some paths out of the variable, but
	* so be it. */
	D("Setting %s\n", temp);
	putenv(strdup(temp));
	#else
	const char* path = getenv("LD_LIBRARY_PATH");
	if (path != NULL && path[0] != '\0') {
	p = bufprint(temp, end, "%s:%s", prefix, path);
	prefix = temp;
	}
	setenv("LD_LIBRARY_PATH",prefix,1);
	D("Setting LD_LIBRARY_PATH=%s\n", prefix);
	#endif
	}

	#ifdef _WIN32
	static char*
	quotePath(const char* path)
	{
	int len = strlen(path);
	char* ret = malloc(len+3);

	ret[0] = '"';
	memcpy(ret+1, path, len);
	ret[len+1] = '"';
	ret[len+2] = '\0';

	return ret;
	}
	#endif /* _WIN32 */