1/*
2 * Main entry of app process.
3 *
4 * Starts the interpreted runtime, then starts up the application.
5 *
6 */
7
8#define LOG_TAG "appproc"
9
10#include <stdio.h>
11#include <stdlib.h>
12#include <sys/prctl.h>
13#include <sys/stat.h>
14#include <unistd.h>
15
16#include <binder/IPCThreadState.h>
17#include <hwbinder/IPCThreadState.h>
18#include <utils/Log.h>
19#include <cutils/memory.h>
20#include <cutils/properties.h>
21#include <cutils/trace.h>
22#include <android_runtime/AndroidRuntime.h>
23#include <private/android_filesystem_config.h>  // for AID_SYSTEM
24
25namespace android {
26
27static void app_usage()
28{
29    fprintf(stderr,
30        "Usage: app_process [java-options] cmd-dir start-class-name [options]\n");
31}
32
33class AppRuntime : public AndroidRuntime
34{
35public:
36    AppRuntime(char* argBlockStart, const size_t argBlockLength)
37        : AndroidRuntime(argBlockStart, argBlockLength)
38        , mClass(NULL)
39    {
40    }
41
42    void setClassNameAndArgs(const String8& className, int argc, char * const *argv) {
43        mClassName = className;
44        for (int i = 0; i < argc; ++i) {
45             mArgs.add(String8(argv[i]));
46        }
47    }
48
49    virtual void onVmCreated(JNIEnv* env)
50    {
51        if (mClassName.isEmpty()) {
52            return; // Zygote. Nothing to do here.
53        }
54
55        /*
56         * This is a little awkward because the JNI FindClass call uses the
57         * class loader associated with the native method we're executing in.
58         * If called in onStarted (from RuntimeInit.finishInit because we're
59         * launching "am", for example), FindClass would see that we're calling
60         * from a boot class' native method, and so wouldn't look for the class
61         * we're trying to look up in CLASSPATH. Unfortunately it needs to,
62         * because the "am" classes are not boot classes.
63         *
64         * The easiest fix is to call FindClass here, early on before we start
65         * executing boot class Java code and thereby deny ourselves access to
66         * non-boot classes.
67         */
68        char* slashClassName = toSlashClassName(mClassName.string());
69        mClass = env->FindClass(slashClassName);
70        if (mClass == NULL) {
71            ALOGE("ERROR: could not find class '%s'\n", mClassName.string());
72        }
73        free(slashClassName);
74
75        mClass = reinterpret_cast<jclass>(env->NewGlobalRef(mClass));
76    }
77
78    virtual void onStarted()
79    {
80        sp<ProcessState> proc = ProcessState::self();
81        ALOGV("App process: starting thread pool.\n");
82        proc->startThreadPool();
83
84        AndroidRuntime* ar = AndroidRuntime::getRuntime();
85        ar->callMain(mClassName, mClass, mArgs);
86
87        IPCThreadState::self()->stopProcess();
88        hardware::IPCThreadState::self()->stopProcess();
89    }
90
91    virtual void onZygoteInit()
92    {
93        sp<ProcessState> proc = ProcessState::self();
94        ALOGV("App process: starting thread pool.\n");
95        proc->startThreadPool();
96    }
97
98    virtual void onExit(int code)
99    {
100        if (mClassName.isEmpty()) {
101            // if zygote
102            IPCThreadState::self()->stopProcess();
103            hardware::IPCThreadState::self()->stopProcess();
104        }
105
106        AndroidRuntime::onExit(code);
107    }
108
109
110    String8 mClassName;
111    Vector<String8> mArgs;
112    jclass mClass;
113};
114
115}
116
117using namespace android;
118
119static size_t computeArgBlockSize(int argc, char* const argv[]) {
120    // TODO: This assumes that all arguments are allocated in
121    // contiguous memory. There isn't any documented guarantee
122    // that this is the case, but this is how the kernel does it
123    // (see fs/exec.c).
124    //
125    // Also note that this is a constant for "normal" android apps.
126    // Since they're forked from zygote, the size of their command line
127    // is the size of the zygote command line.
128    //
129    // We change the process name of the process by over-writing
130    // the start of the argument block (argv[0]) with the new name of
131    // the process, so we'd mysteriously start getting truncated process
132    // names if the zygote command line decreases in size.
133    uintptr_t start = reinterpret_cast<uintptr_t>(argv[0]);
134    uintptr_t end = reinterpret_cast<uintptr_t>(argv[argc - 1]);
135    end += strlen(argv[argc - 1]) + 1;
136    return (end - start);
137}
138
139static void maybeCreateDalvikCache() {
140#if defined(__aarch64__)
141    static const char kInstructionSet[] = "arm64";
142#elif defined(__x86_64__)
143    static const char kInstructionSet[] = "x86_64";
144#elif defined(__arm__)
145    static const char kInstructionSet[] = "arm";
146#elif defined(__i386__)
147    static const char kInstructionSet[] = "x86";
148#elif defined (__mips__) && !defined(__LP64__)
149    static const char kInstructionSet[] = "mips";
150#elif defined (__mips__) && defined(__LP64__)
151    static const char kInstructionSet[] = "mips64";
152#else
153#error "Unknown instruction set"
154#endif
155    const char* androidRoot = getenv("ANDROID_DATA");
156    LOG_ALWAYS_FATAL_IF(androidRoot == NULL, "ANDROID_DATA environment variable unset");
157
158    char dalvikCacheDir[PATH_MAX];
159    const int numChars = snprintf(dalvikCacheDir, PATH_MAX,
160            "%s/dalvik-cache/%s", androidRoot, kInstructionSet);
161    LOG_ALWAYS_FATAL_IF((numChars >= PATH_MAX || numChars < 0),
162            "Error constructing dalvik cache : %s", strerror(errno));
163
164    int result = mkdir(dalvikCacheDir, 0711);
165    LOG_ALWAYS_FATAL_IF((result < 0 && errno != EEXIST),
166            "Error creating cache dir %s : %s", dalvikCacheDir, strerror(errno));
167
168    // We always perform these steps because the directory might
169    // already exist, with wider permissions and a different owner
170    // than we'd like.
171    result = chown(dalvikCacheDir, AID_ROOT, AID_ROOT);
172    LOG_ALWAYS_FATAL_IF((result < 0), "Error changing dalvik-cache ownership : %s", strerror(errno));
173
174    result = chmod(dalvikCacheDir, 0711);
175    LOG_ALWAYS_FATAL_IF((result < 0),
176            "Error changing dalvik-cache permissions : %s", strerror(errno));
177}
178
179#if defined(__LP64__)
180static const char ABI_LIST_PROPERTY[] = "ro.product.cpu.abilist64";
181static const char ZYGOTE_NICE_NAME[] = "zygote64";
182#else
183static const char ABI_LIST_PROPERTY[] = "ro.product.cpu.abilist32";
184static const char ZYGOTE_NICE_NAME[] = "zygote";
185#endif
186
187int main(int argc, char* const argv[])
188{
189    if (!LOG_NDEBUG) {
190      String8 argv_String;
191      for (int i = 0; i < argc; ++i) {
192        argv_String.append("\"");
193        argv_String.append(argv[i]);
194        argv_String.append("\" ");
195      }
196      ALOGV("app_process main with argv: %s", argv_String.string());
197    }
198
199    AppRuntime runtime(argv[0], computeArgBlockSize(argc, argv));
200    // Process command line arguments
201    // ignore argv[0]
202    argc--;
203    argv++;
204
205    // Everything up to '--' or first non '-' arg goes to the vm.
206    //
207    // The first argument after the VM args is the "parent dir", which
208    // is currently unused.
209    //
210    // After the parent dir, we expect one or more the following internal
211    // arguments :
212    //
213    // --zygote : Start in zygote mode
214    // --start-system-server : Start the system server.
215    // --application : Start in application (stand alone, non zygote) mode.
216    // --nice-name : The nice name for this process.
217    //
218    // For non zygote starts, these arguments will be followed by
219    // the main class name. All remaining arguments are passed to
220    // the main method of this class.
221    //
222    // For zygote starts, all remaining arguments are passed to the zygote.
223    // main function.
224    //
225    // Note that we must copy argument string values since we will rewrite the
226    // entire argument block when we apply the nice name to argv0.
227    //
228    // As an exception to the above rule, anything in "spaced commands"
229    // goes to the vm even though it has a space in it.
230    const char* spaced_commands[] = { "-cp", "-classpath" };
231    // Allow "spaced commands" to be succeeded by exactly 1 argument (regardless of -s).
232    bool known_command = false;
233
234    int i;
235    for (i = 0; i < argc; i++) {
236        if (known_command == true) {
237          runtime.addOption(strdup(argv[i]));
238          // The static analyzer gets upset that we don't ever free the above
239          // string. Since the allocation is from main, leaking it doesn't seem
240          // problematic. NOLINTNEXTLINE
241          ALOGV("app_process main add known option '%s'", argv[i]);
242          known_command = false;
243          continue;
244        }
245
246        for (int j = 0;
247             j < static_cast<int>(sizeof(spaced_commands) / sizeof(spaced_commands[0]));
248             ++j) {
249          if (strcmp(argv[i], spaced_commands[j]) == 0) {
250            known_command = true;
251            ALOGV("app_process main found known command '%s'", argv[i]);
252          }
253        }
254
255        if (argv[i][0] != '-') {
256            break;
257        }
258        if (argv[i][1] == '-' && argv[i][2] == 0) {
259            ++i; // Skip --.
260            break;
261        }
262
263        runtime.addOption(strdup(argv[i]));
264        // The static analyzer gets upset that we don't ever free the above
265        // string. Since the allocation is from main, leaking it doesn't seem
266        // problematic. NOLINTNEXTLINE
267        ALOGV("app_process main add option '%s'", argv[i]);
268    }
269
270    // Parse runtime arguments.  Stop at first unrecognized option.
271    bool zygote = false;
272    bool startSystemServer = false;
273    bool application = false;
274    String8 niceName;
275    String8 className;
276
277    ++i;  // Skip unused "parent dir" argument.
278    while (i < argc) {
279        const char* arg = argv[i++];
280        if (strcmp(arg, "--zygote") == 0) {
281            zygote = true;
282            niceName = ZYGOTE_NICE_NAME;
283        } else if (strcmp(arg, "--start-system-server") == 0) {
284            startSystemServer = true;
285        } else if (strcmp(arg, "--application") == 0) {
286            application = true;
287        } else if (strncmp(arg, "--nice-name=", 12) == 0) {
288            niceName.setTo(arg + 12);
289        } else if (strncmp(arg, "--", 2) != 0) {
290            className.setTo(arg);
291            break;
292        } else {
293            --i;
294            break;
295        }
296    }
297
298    Vector<String8> args;
299    if (!className.isEmpty()) {
300        // We're not in zygote mode, the only argument we need to pass
301        // to RuntimeInit is the application argument.
302        //
303        // The Remainder of args get passed to startup class main(). Make
304        // copies of them before we overwrite them with the process name.
305        args.add(application ? String8("application") : String8("tool"));
306        runtime.setClassNameAndArgs(className, argc - i, argv + i);
307
308        if (!LOG_NDEBUG) {
309          String8 restOfArgs;
310          char* const* argv_new = argv + i;
311          int argc_new = argc - i;
312          for (int k = 0; k < argc_new; ++k) {
313            restOfArgs.append("\"");
314            restOfArgs.append(argv_new[k]);
315            restOfArgs.append("\" ");
316          }
317          ALOGV("Class name = %s, args = %s", className.string(), restOfArgs.string());
318        }
319    } else {
320        // We're in zygote mode.
321        maybeCreateDalvikCache();
322
323        if (startSystemServer) {
324            args.add(String8("start-system-server"));
325        }
326
327        char prop[PROP_VALUE_MAX];
328        if (property_get(ABI_LIST_PROPERTY, prop, NULL) == 0) {
329            LOG_ALWAYS_FATAL("app_process: Unable to determine ABI list from property %s.",
330                ABI_LIST_PROPERTY);
331            return 11;
332        }
333
334        String8 abiFlag("--abi-list=");
335        abiFlag.append(prop);
336        args.add(abiFlag);
337
338        // In zygote mode, pass all remaining arguments to the zygote
339        // main() method.
340        for (; i < argc; ++i) {
341            args.add(String8(argv[i]));
342        }
343    }
344
345    if (!niceName.isEmpty()) {
346        runtime.setArgv0(niceName.string(), true /* setProcName */);
347    }
348
349    if (zygote) {
350        runtime.start("com.android.internal.os.ZygoteInit", args, zygote);
351    } else if (className) {
352        runtime.start("com.android.internal.os.RuntimeInit", args, zygote);
353    } else {
354        fprintf(stderr, "Error: no class name or --zygote supplied.\n");
355        app_usage();
356        LOG_ALWAYS_FATAL("app_process: no class name or --zygote supplied.");
357    }
358}
359