Comment obtenir un nom d’utilisateur avec uid sur Android

J’ai écrit une classe d’utilitaires pour obtenir le nom UID / GID en codant en dur les valeurs d’ android_filesystem_config.h .

Usage:

 Ssortingng uid = AndroidFilesystemConfig.getNameForId(1000); 

AndroidFilesystemConfig.java

 import android.os.Build; import android.util.SparseArray; import java.util.Locale; /** * 
System Users and Groups for the Android platform as specified in * android_filesystem_config.h.
 * * 
Last updated: April 20th, 2016
 * * 
Note: Some OEMs may have specific UIDs for other system users not in this class.
 */ public class AndroidFilesystemConfig { /* first app user */ private static final int AID_APP = 10000; /* offset for uid ranges for each user */ private static final int AID_USER = 100000; /* start of gids for apps in each user to share */ private static final int AID_SHARED_GID_START = 50000; /* end of gids for apps in each user to share */ private static final int AID_SHARED_GID_END = 59999; private static final SparseArray SYSTEM_IDS = new SparseArray<>(); static { putSystemId(0, "root"); /* traditional unix root user */ putSystemId(1000, "system"); /* system server */ putSystemId(1001, "radio"); /* telephony subsystem, RIL */ putSystemId(1002, "bluetooth"); /* bluetooth subsystem */ putSystemId(1003, "graphics"); /* graphics devices */ putSystemId(1004, "input"); /* input devices */ putSystemId(1005, "audio"); /* audio devices */ putSystemId(1006, "camera"); /* camera devices */ putSystemId(1007, "log"); /* log devices */ putSystemId(1008, "compass"); /* compass device */ putSystemId(1009, "mount"); /* mountd socket */ putSystemId(1010, "wifi"); /* wifi subsystem */ putSystemId(1011, "adb"); /* android debug bridge (adbd) */ putSystemId(1012, "install"); /* group for installing packages */ putSystemId(1013, "media"); /* mediaserver process */ putSystemId(1014, "dhcp"); /* dhcp client */ putSystemId(1015, "sdcard_rw"); /* external storage write access */ putSystemId(1016, "vpn"); /* vpn system */ putSystemId(1017, "keystore"); /* keystore subsystem */ putSystemId(1018, "usb"); /* USB devices */ putSystemId(1019, "drm"); /* DRM server */ putSystemId(1020, "mdnsr"); /* MulticastDNSResponder (service discovery) */ putSystemId(1021, "gps"); /* GPS daemon */ // 1022 is deprecated and not used. putSystemId(1023, "media_rw"); /* internal media storage write access */ putSystemId(1024, "mtp"); /* MTP USB driver access */ // 1025 is deprecated and not used. putSystemId(1026, "drmrpc"); /* group for drm rpc */ putSystemId(1027, "nfc"); /* nfc subsystem */ putSystemId(1028, "sdcard_r"); /* external storage read access */ putSystemId(1029, "clat"); /* clat part of nat464 */ putSystemId(1030, "loop_radio"); /* loop radio devices */ putSystemId(1031, "mediadrm"); /* MediaDrm plugins */ putSystemId(1032, "package_info"); /* access to installed package details */ putSystemId(1033, "sdcard_pics"); /* external storage photos access */ putSystemId(1034, "sdcard_av"); /* external storage audio/video access */ putSystemId(1035, "sdcard_all"); /* access all users external storage */ putSystemId(1036, "logd"); /* log daemon */ putSystemId(1037, "shared_relro"); /* creator of shared GNU RELRO files */ putSystemId(1038, "dbus"); /* dbus-daemon IPC broker process */ putSystemId(1039, "tlsdate"); /* tlsdate unprivileged user */ putSystemId(1040, "mediaex"); /* mediaextractor process */ putSystemId(1041, "audioserver"); /* audioserver process */ putSystemId(1042, "metrics_coll"); /* metrics_collector process */ putSystemId(1043, "metricsd"); /* metricsd process */ putSystemId(1044, "webserv"); /* webservd process */ putSystemId(1045, "debuggerd"); /* debuggerd unprivileged user */ putSystemId(1046, "mediacodec"); /* mediacodec process */ putSystemId(1047, "cameraserver"); /* cameraserver process */ putSystemId(1048, "firewall"); /* firewalld process */ putSystemId(1049, "trunks"); /* trunksd process (TPM daemon) */ putSystemId(1050, "nvram"); /* Access-controlled NVRAM */ putSystemId(1051, "dns"); /* DNS resolution daemon (system: netd) */ putSystemId(1052, "dns_tether"); /* DNS resolution daemon (tether: dnsmasq) */ putSystemId(1053, "webview_zygote"); /* WebView zygote process */ putSystemId(1054, "vehicle_network"); /* Vehicle network service */ putSystemId(1055, "media_audio"); /* GID for audio files on internal media storage */ putSystemId(1056, "media_video"); /* GID for video files on internal media storage */ putSystemId(1057, "media_image"); /* GID for image files on internal media storage */ putSystemId(2000, "shell"); /* adb and debug shell user */ putSystemId(2001, "cache"); /* cache access */ putSystemId(2002, "diag"); /* access to diagnostic resources */ /* The range 2900-2999 is reserved for OEMs */ // The 3000 series are intended for use as supplemental group id's only. They indicate // special Android capabilities that the kernel is aware of. putSystemId(3001, "net_bt_admin"); /* bluetooth: get any socket */ putSystemId(3002, "net_bt"); /* bluetooth: get sco, rfcomm or l2cap sockets */ putSystemId(3003, "inet"); /* can get AF_INET and AF_INET6 sockets */ putSystemId(3004, "net_raw"); /* can get raw INET sockets */ putSystemId(3005, "net_admin"); /* can configure interfaces and routing tables. */ putSystemId(3006, "net_bw_stats"); /* read bandwidth statistics */ putSystemId(3007, "net_bw_acct"); /* change bandwidth statistics accounting */ putSystemId(3008, "net_bt_stack"); /* bluetooth: access config files */ putSystemId(3009, "readproc"); /* Allow /proc read access */ putSystemId(3010, "wakelock"); /* Allow system wakelock read/write access */ /* The range 5000-5999 is also reserved for OEMs. */ putSystemId(9997, "everybody"); /* shared between all apps in the same profile */ putSystemId(9998, "misc"); /* access to misc storage */ putSystemId(9999, "nobody"); } private static void putSystemId(int id, String name) { // Check if the uid exists before adding it so we don't add unsupported ids. if (android.os.Process.getUidForName(name) != id) { // Not valid on this system. Most likely due to a lower API. return; } SYSTEM_IDS.put(id, name); } /** * @return An array of system UIDs */ public static SparseArray getSystemIds() { return SYSTEM_IDS; } /** * Returns the UID/GID name assigned to a particular id, or {@code null} if there is none. * * @param id * The UID/GID of a process or file * @return the name of the UID/GID or {@code null} if the id is unrecognized. */ public static Ssortingng getNameForId(int id) { Ssortingng name = SYSTEM_IDS.get(id); if (name == null) { if (id >= AID_SHARED_GID_START && id <= AID_SHARED_GID_END) { name = String.format(Locale.ENGLISH, "all_a%d", id - AID_SHARED_GID_START); } else { int appId = id - AID_APP; int userId = 0; // loop until we get the correct user id. // 100000 is the offset for each user. while (appId > AID_USER) { appId -= AID_USER; userId++; } if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) { // u{user_id}_a{app_id} is used on API 17+ for multiple user account support. name = Ssortingng.format(Locale.ENGLISH, "u%d_a%d", userId, appId); } else { // app_{app_id} is used below API 17. name = Ssortingng.format(Locale.ENGLISH, "app_%d", appId); } } } return name; } private AndroidFilesystemConfig() { throw new AssertionError("no instances"); } } 

Utilisation de la reflection:

Inspiré par la réponse d’odexide, voici une reflection vraiment laide que je ne vous conseillerais pas d’utiliser et qui obtiendra le nom UID / GID de getpwuid (uid_t) :

 public static Ssortingng getNameForUid(int id) { try { Class clazz = Class.forName("libcore.io.Libcore"); Field field = clazz.getDeclaredField("os"); if (!field.isAccessible()) { field.setAccessible(true); } Object os = field.get(null); if (os != null) { Method getpwuid = os.getClass().getMethod("getpwuid", int.class); if (getpwuid != null) { if (!getpwuid.isAccessible()) { getpwuid.setAccessible(true); } Object passwd = getpwuid.invoke(os, id); if (passwd != null) { Field pw_name = passwd.getClass().getDeclaredField("pw_name"); if (!pw_name.isAccessible()) { pw_name.setAccessible(true); } return (Ssortingng) pw_name.get(passwd); } } } } catch (Exception ignored) { } return null; } 

Les UID sont codés en dur pour l’implémentation Android de libc (bionic) et sont également fournis dans des plages pour les applications. android_filesystem_config.h explique le mappage.

Vous devriez pouvoir utiliser les stubs bioniques (c ++) pour getpwuid (uid_t) .

Pour plus d’informations sur les stubs, consultez cette documentation AOSP .