Add 'emulator' launcher program.

This patch renames the current ARM-specific emulator binary to 'emulator-arm'
and introduces a new tiny (less than 20KB) 'emulator' launcher program.

The role of 'emulator' is to launch either 'emulator-arm' or 'emulator-x86'
based on the target AVD or platform build being used.

This program will be replaced in the future by what is currently known
as 'emulator-ui', but is a good placeholder until this work is completed.

+ Move some utility functions from android/avd/info.[hc] to
  android/avd/util.[hc] so that 'emulator' can use them directly.

IMPORTANT: For platform builds, the target architecture is detected
           automatically by parsing the build.prop file.

           For SDK AVDs however, there is no easy way to determine the
           target architecture, so the patch adds a new hw.cpu.arch
           property which can have value 'arm' or 'x86'

Change-Id: I0084c196695a75c8b9230ba716b3cd2e12610ded

1 files changed, 169 insertions, 0 deletions

diff --git a/android/main-emulator.c b/android/main-emulator.c
new file mode 100644
index 0000000..211291b
--- /dev/null
+++ b/android/main-emulator.c
@@ -0,0 +1,169 @@
+/* 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
+
+/* Forward declarations */
+static char* getTargetEmulatorPath(const char* progName, const char* avdArch);
+
+/* Main routine */
+int main(int argc, char** argv)
+{
+    const char* avdName = NULL;
+    char*       avdArch = NULL;
+    char*       emulatorPath;
+
+    /* 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 an avd name
+     * Either in the form or '-avd <name>' or '@<name>'
+     */
+    int  nn;
+    for (nn = 1; nn < argc; nn++) {
+        const char* opt = argv[nn];
+
+        if (!strcmp(opt,"-qemu"))
+            break;
+
+        if (!strcmp(opt,"-avd") && nn+1 < argc) {
+            avdName = argv[nn+1];
+            break;
+        }
+        else if (opt[0] == '@' && opt[1] != '\0') {
+            avdName = opt+1;
+            break;
+        }
+    }
+
+    /* 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);
+    }
+
+    /* Find the architecture-specific program in the same directory */
+    emulatorPath = getTargetEmulatorPath(argv[0], avdArch);
+    D("Found target-specific emulator binary: %s\n", emulatorPath);
+
+    /* Replace it in our command-line */
+    argv[0] = emulatorPath;
+
+    /* Launch it with the same set of options ! */
+    /* execv() should be available on Windows with mingw32 */
+    execv(emulatorPath, argv);
+
+    /* We could not launch the program ! */
+    fprintf(stderr, "Could not launch '%s': %s\n", emulatorPath, strerror(errno));
+    return errno;
+}
+
+
+/* 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)
+{
+    char*  progDir;
+    char   temp[PATH_MAX], *p=temp, *end=p+sizeof(temp);
+#ifdef _WIN32
+    const char* exeExt = ".exe";
+#else
+    const char* exeExt = "";
+#endif
+
+    /* Get program's directory name in progDir */
+    path_split(progName, &progDir, NULL);
+
+    p = bufprint(temp, end, "%s/emulator-%s%s", progDir, avdArch, exeExt);
+    free(progDir);
+    if (p >= end) {
+        APANIC("Path too long: %s\n", progName);
+    }
+
+    if (path_exists(temp)) {
+        return strdup(temp);
+    }
+
+    /* 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
+        p = bufprint(temp, end, "emulator-%s%s", avdArch, exeExt);
+        if (p < end) {
+            char*  resolved = path_search_exec(temp);
+            if (resolved != NULL)
+                return resolved;
+        }
+    }
+
+    /* Otherwise, the program is missing */
+    APANIC("Missing arch-specific emulator program: %s\n", temp);
+    return NULL;
+}