init: Let property_get return std::string.

Bug: 22654233

Change-Id: Id6091f58432f75e966b9871256049fbe17766c10
diff --git a/init/bootchart.cpp b/init/bootchart.cpp
index 81b20fa..e5b153a 100644
--- a/init/bootchart.cpp
+++ b/init/bootchart.cpp
@@ -77,8 +77,8 @@
         return;
     }
 
-    char fingerprint[PROP_VALUE_MAX];
-    if (property_get("ro.build.fingerprint", fingerprint) == -1) {
+    std::string fingerprint = property_get("ro.build.fingerprint");
+    if (fingerprint.empty()) {
         return;
     }
 
@@ -92,7 +92,7 @@
     fprintf(out, "version = Android init 0.8 " __TIME__  "\n");
     fprintf(out, "title = Boot chart for Android (%s)\n", date);
     fprintf(out, "system.uname = %s %s %s %s\n", uts.sysname, uts.release, uts.version, uts.machine);
-    fprintf(out, "system.release = %s\n", fingerprint);
+    fprintf(out, "system.release = %s\n", fingerprint.c_str());
     // TODO: use /proc/cpuinfo "model name" line for x86, "Processor" line for arm.
     fprintf(out, "system.cpu = %s\n", uts.machine);
     fprintf(out, "system.kernel.options = %s\n", kernel_cmdline.c_str());
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 8d47da4..e2c033a 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -920,9 +920,8 @@
         return -1;
     }
 
-    char prop_value[PROP_VALUE_MAX] = {0};
-    property_get("ro.crypto.type", prop_value);
-    if (strcmp(prop_value, "file")) {
+    std::string prop_value = property_get("ro.crypto.type");
+    if (prop_value != "file") {
         return 0;
     }
 
diff --git a/init/init.cpp b/init/init.cpp
index 4d62c87..cd19647 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -76,7 +76,7 @@
 static struct command *cur_command = NULL;
 
 static int have_console;
-static char console_name[PROP_VALUE_MAX] = "/dev/console";
+static std::string console_name = "/dev/console";
 static time_t process_needs_restart;
 
 static const char *ENV[32];
@@ -160,7 +160,7 @@
 static void open_console()
 {
     int fd;
-    if ((fd = open(console_name, O_RDWR)) < 0) {
+    if ((fd = open(console_name.c_str(), O_RDWR)) < 0) {
         fd = open("/dev/null", O_RDWR);
     }
     ioctl(fd, TIOCSCTTY, 0);
@@ -727,12 +727,12 @@
 
 static int console_init_action(int nargs, char **args)
 {
-    char console[PROP_VALUE_MAX];
-    if (property_get("ro.boot.console", console) > 0) {
-        snprintf(console_name, sizeof(console_name), "/dev/%s", console);
+    std::string console = property_get("ro.boot.console");
+    if (!console.empty()) {
+        console_name = "/dev/" + console;
     }
 
-    int fd = open(console_name, O_RDWR | O_CLOEXEC);
+    int fd = open(console_name.c_str(), O_RDWR | O_CLOEXEC);
     if (fd >= 0)
         have_console = 1;
     close(fd);
@@ -793,9 +793,8 @@
         { "ro.boot.revision",   "ro.revision",   "0", },
     };
     for (size_t i = 0; i < ARRAY_SIZE(prop_map); i++) {
-        char value[PROP_VALUE_MAX];
-        int rc = property_get(prop_map[i].src_prop, value);
-        property_set(prop_map[i].dst_prop, (rc > 0) ? value : prop_map[i].default_value);
+        std::string value = property_get(prop_map[i].src_prop);
+        property_set(prop_map[i].dst_prop, (!value.empty()) ? value.c_str() : prop_map[i].default_value);
     }
 }
 
@@ -1054,8 +1053,8 @@
     queue_builtin_action(mix_hwrng_into_linux_rng_action, "mix_hwrng_into_linux_rng");
 
     // Don't mount filesystems or start core system services in charger mode.
-    char bootmode[PROP_VALUE_MAX];
-    if (property_get("ro.bootmode", bootmode) > 0 && strcmp(bootmode, "charger") == 0) {
+    std::string bootmode = property_get("ro.bootmode");
+    if (bootmode == "charger") {
         action_for_each_trigger("charger", action_add_queue_tail);
     } else {
         action_for_each_trigger("late-init", action_add_queue_tail);
diff --git a/init/init_parser.cpp b/init/init_parser.cpp
index 956ed25..41b89f1 100644
--- a/init/init_parser.cpp
+++ b/init/init_parser.cpp
@@ -247,9 +247,7 @@
     while (*src_ptr && left > 0) {
         char *c;
         char prop[PROP_NAME_MAX + 1];
-        char prop_val[PROP_VALUE_MAX];
         int prop_len = 0;
-        int prop_val_len;
 
         c = strchr(src_ptr, '$');
         if (!c) {
@@ -307,14 +305,14 @@
             goto err;
         }
 
-        prop_val_len = property_get(prop, prop_val);
-        if (!prop_val_len) {
+        std::string prop_val = property_get(prop);
+        if (prop_val.empty()) {
             ERROR("property '%s' doesn't exist while expanding '%s'\n",
                   prop, src);
             goto err;
         }
 
-        ret = push_chars(&dst_ptr, &left, prop_val, prop_val_len);
+        ret = push_chars(&dst_ptr, &left, prop_val.c_str(), prop_val.size());
         if (ret < 0)
             goto err_nospace;
         src_ptr = c;
@@ -586,17 +584,13 @@
                 } else {
                      const char* equals = strchr(test, '=');
                      if (equals) {
-                         char prop_name[PROP_NAME_MAX + 1];
-                         char value[PROP_VALUE_MAX];
                          int length = equals - test;
                          if (length <= PROP_NAME_MAX) {
-                             int ret;
-                             memcpy(prop_name, test, length);
-                             prop_name[length] = 0;
+                             std::string prop_name(test, length);
+                             std::string value = property_get(prop_name.c_str());
 
                              /* does the property exist, and match the trigger value? */
-                             ret = property_get(prop_name, value);
-                             if (ret > 0 && (!strcmp(equals + 1, value) ||
+                             if (!value.empty() && (!strcmp(equals + 1, value.c_str()) ||
                                 !strcmp(equals + 1, "*"))) {
                                  continue;
                              }
diff --git a/init/keychords.cpp b/init/keychords.cpp
index 10d9573..c4ebdf9 100644
--- a/init/keychords.cpp
+++ b/init/keychords.cpp
@@ -64,19 +64,18 @@
 
 static void handle_keychord() {
     struct service *svc;
-    char adb_enabled[PROP_VALUE_MAX];
     int ret;
     __u16 id;
 
-    // Only handle keychords if adb is enabled.
-    property_get("init.svc.adbd", adb_enabled);
     ret = read(keychord_fd, &id, sizeof(id));
     if (ret != sizeof(id)) {
         ERROR("could not read keychord id\n");
         return;
     }
 
-    if (!strcmp(adb_enabled, "running")) {
+    // Only handle keychords if adb is enabled.
+    std::string adb_enabled = property_get("init.svc.adbd");
+    if (adb_enabled == "running") {
         svc = service_find_by_keychord(id);
         if (svc) {
             INFO("Starting service %s from keychord\n", svc->name);
diff --git a/init/property_service.cpp b/init/property_service.cpp
index 5b7a1cb..aa939a5 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -141,9 +141,10 @@
     return check_mac_perms(name, sctx);
 }
 
-int __property_get(const char *name, char *value)
-{
-    return __system_property_get(name, value);
+std::string property_get(const char* name) {
+    char value[PROP_VALUE_MAX] = {0};
+    __system_property_get(name, value);
+    return value;
 }
 
 static void write_persistent_property(const char *name, const char *value)
@@ -491,9 +492,8 @@
 
 static void load_override_properties() {
     if (ALLOW_LOCAL_PROP_OVERRIDE) {
-        char debuggable[PROP_VALUE_MAX];
-        int ret = property_get("ro.debuggable", debuggable);
-        if (ret && (strcmp(debuggable, "1") == 0)) {
+        std::string debuggable = property_get("ro.debuggable");
+        if (debuggable == "1") {
             load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE, NULL);
         }
     }
@@ -511,19 +511,17 @@
 }
 
 void load_recovery_id_prop() {
-    char fstab_filename[PROP_VALUE_MAX + sizeof(FSTAB_PREFIX)];
-    char propbuf[PROP_VALUE_MAX];
-    int ret = property_get("ro.hardware", propbuf);
-    if (!ret) {
+    std::string ro_hardware = property_get("ro.hardware");
+    if (ro_hardware.empty()) {
         ERROR("ro.hardware not set - unable to load recovery id\n");
         return;
     }
-    snprintf(fstab_filename, sizeof(fstab_filename), FSTAB_PREFIX "%s", propbuf);
+    std::string fstab_filename = FSTAB_PREFIX + ro_hardware;
 
-    std::unique_ptr<fstab, void(*)(fstab*)> tab(fs_mgr_read_fstab(fstab_filename),
+    std::unique_ptr<fstab, void(*)(fstab*)> tab(fs_mgr_read_fstab(fstab_filename.c_str()),
             fs_mgr_free_fstab);
     if (!tab) {
-        ERROR("unable to read fstab %s: %s\n", fstab_filename, strerror(errno));
+        ERROR("unable to read fstab %s: %s\n", fstab_filename.c_str(), strerror(errno));
         return;
     }
 
diff --git a/init/property_service.h b/init/property_service.h
index a27053d..51d7404 100644
--- a/init/property_service.h
+++ b/init/property_service.h
@@ -19,6 +19,7 @@
 
 #include <stddef.h>
 #include <sys/system_properties.h>
+#include <string>
 
 extern void property_init(void);
 extern void property_load_boot_defaults(void);
@@ -26,30 +27,9 @@
 extern void load_all_props(void);
 extern void start_property_service(void);
 void get_property_workspace(int *fd, int *sz);
-extern int __property_get(const char *name, char *value);
+std::string property_get(const char* name);
 extern int property_set(const char *name, const char *value);
 extern bool properties_initialized();
 
-#ifndef __clang__
-extern void __property_get_size_error()
-    __attribute__((__error__("property_get called with too small buffer")));
-#else
-extern void __property_get_size_error();
-#endif
-
-static inline
-__attribute__ ((always_inline))
-__attribute__ ((gnu_inline))
-#ifndef __clang__
-__attribute__ ((artificial))
-#endif
-int property_get(const char *name, char *value)
-{
-    size_t value_len = __builtin_object_size(value, 0);
-    if (value_len != PROP_VALUE_MAX)
-        __property_get_size_error();
-
-    return __property_get(name, value);
-}
 
 #endif	/* _INIT_PROPERTY_H */
diff --git a/init/ueventd.cpp b/init/ueventd.cpp
index c63fdaa..75924cb 100644
--- a/init/ueventd.cpp
+++ b/init/ueventd.cpp
@@ -59,11 +59,10 @@
     cb.func_log = selinux_klog_callback;
     selinux_set_callback(SELINUX_CB_LOG, cb);
 
-    char hardware[PROP_VALUE_MAX];
-    property_get("ro.hardware", hardware);
+    std::string hardware = property_get("ro.hardware");
 
     ueventd_parse_config_file("/ueventd.rc");
-    ueventd_parse_config_file(android::base::StringPrintf("/ueventd.%s.rc", hardware).c_str());
+    ueventd_parse_config_file(android::base::StringPrintf("/ueventd.%s.rc", hardware.c_str()).c_str());
 
     device_init();