/* * Copyright (C) 2012-2013 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "CommandListener.h" #include "LogBuffer.h" #include "LogListener.h" #include "LogAudit.h" #include "LogKlog.h" #include "LogUtils.h" #define KMSG_PRIORITY(PRI) \ '<', \ '0' + LOG_MAKEPRI(LOG_DAEMON, LOG_PRI(PRI)) / 10, \ '0' + LOG_MAKEPRI(LOG_DAEMON, LOG_PRI(PRI)) % 10, \ '>' // // The service is designed to be run by init, it does not respond well // to starting up manually. When starting up manually the sockets will // fail to open typically for one of the following reasons: // EADDRINUSE if logger is running. // EACCESS if started without precautions (below) // // Here is a cookbook procedure for starting up logd manually assuming // init is out of the way, pedantically all permissions and selinux // security is put back in place: // // setenforce 0 // rm /dev/socket/logd* // chmod 777 /dev/socket // # here is where you would attach the debugger or valgrind for example // runcon u:r:logd:s0 /system/bin/logd /dev/null 2>&1 & // sleep 1 // chmod 755 /dev/socket // chown logd.logd /dev/socket/logd* // restorecon /dev/socket/logd* // setenforce 1 // // If minimalism prevails, typical for debugging and security is not a concern: // // setenforce 0 // chmod 777 /dev/socket // logd // static int drop_privs() { struct sched_param param; memset(¶m, 0, sizeof(param)); if (set_sched_policy(0, SP_BACKGROUND) < 0) { return -1; } if (sched_setscheduler((pid_t) 0, SCHED_BATCH, ¶m) < 0) { return -1; } if (setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND) < 0) { return -1; } if (prctl(PR_SET_KEEPCAPS, 1) < 0) { return -1; } gid_t groups[] = { AID_READPROC }; if (setgroups(sizeof(groups) / sizeof(groups[0]), groups) == -1) { return -1; } if (setgid(AID_LOGD) != 0) { return -1; } if (setuid(AID_LOGD) != 0) { return -1; } struct __user_cap_header_struct capheader; struct __user_cap_data_struct capdata[2]; memset(&capheader, 0, sizeof(capheader)); memset(&capdata, 0, sizeof(capdata)); capheader.version = _LINUX_CAPABILITY_VERSION_3; capheader.pid = 0; capdata[CAP_TO_INDEX(CAP_SYSLOG)].permitted = CAP_TO_MASK(CAP_SYSLOG); capdata[CAP_TO_INDEX(CAP_AUDIT_CONTROL)].permitted |= CAP_TO_MASK(CAP_AUDIT_CONTROL); capdata[0].effective = capdata[0].permitted; capdata[1].effective = capdata[1].permitted; capdata[0].inheritable = 0; capdata[1].inheritable = 0; if (capset(&capheader, &capdata[0]) < 0) { return -1; } return 0; } // Property helper static bool check_flag(const char *prop, const char *flag) { const char *cp = strcasestr(prop, flag); if (!cp) { return false; } // We only will document comma (,) static const char sep[] = ",:;|+ \t\f"; if ((cp != prop) && !strchr(sep, cp[-1])) { return false; } cp += strlen(flag); return !*cp || !!strchr(sep, *cp); } bool property_get_bool(const char *key, int flag) { char def[PROPERTY_VALUE_MAX]; char property[PROPERTY_VALUE_MAX]; def[0] = '\0'; if (flag & BOOL_DEFAULT_FLAG_PERSIST) { char newkey[PROPERTY_KEY_MAX]; snprintf(newkey, sizeof(newkey), "ro.%s", key); property_get(newkey, property, ""); // persist properties set by /data require innoculation with // logd-reinit. They may be set in init.rc early and function, but // otherwise are defunct unless reset. Do not rely on persist // properties for startup-only keys unless you are willing to restart // logd daemon (not advised). snprintf(newkey, sizeof(newkey), "persist.%s", key); property_get(newkey, def, property); } property_get(key, property, def); if (check_flag(property, "true")) { return true; } if (check_flag(property, "false")) { return false; } if (check_flag(property, "eng")) { flag |= BOOL_DEFAULT_FLAG_ENG; } // this is really a "not" flag if (check_flag(property, "svelte")) { flag |= BOOL_DEFAULT_FLAG_SVELTE; } // Sanity Check if (flag & (BOOL_DEFAULT_FLAG_SVELTE | BOOL_DEFAULT_FLAG_ENG)) { flag &= ~BOOL_DEFAULT_FLAG_TRUE_FALSE; flag |= BOOL_DEFAULT_TRUE; } if ((flag & BOOL_DEFAULT_FLAG_SVELTE) && property_get_bool("ro.config.low_ram", BOOL_DEFAULT_FALSE)) { return false; } if (flag & BOOL_DEFAULT_FLAG_ENG) { property_get("ro.build.type", property, ""); if (!strcmp(property, "user")) { return false; } } return (flag & BOOL_DEFAULT_FLAG_TRUE_FALSE) != BOOL_DEFAULT_FALSE; } // Remove the static, and use this variable // globally for debugging if necessary. eg: // write(fdDmesg, "I am here\n", 10); static int fdDmesg = -1; static sem_t uidName; static uid_t uid; static char *name; static sem_t reinit; static bool reinit_running = false; static LogBuffer *logBuf = NULL; static bool package_list_parser_cb(pkg_info *info, void * /* userdata */) { bool rc = true; if (info->uid == uid) { name = strdup(info->name); // false to stop processing rc = false; } packagelist_free(info); return rc; } static void *reinit_thread_start(void * /*obj*/) { prctl(PR_SET_NAME, "logd.daemon"); set_sched_policy(0, SP_BACKGROUND); setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND); setgid(AID_SYSTEM); setuid(AID_SYSTEM); while (reinit_running && !sem_wait(&reinit) && reinit_running) { // uidToName Privileged Worker if (uid) { name = NULL; packagelist_parse(package_list_parser_cb, NULL); uid = 0; sem_post(&uidName); continue; } if (fdDmesg >= 0) { static const char reinit_message[] = { KMSG_PRIORITY(LOG_INFO), 'l', 'o', 'g', 'd', '.', 'd', 'a', 'e', 'm', 'o', 'n', ':', ' ', 'r', 'e', 'i', 'n', 'i', 't', '\n' }; write(fdDmesg, reinit_message, sizeof(reinit_message)); } // Anything that reads persist. if (logBuf) { logBuf->init(); logBuf->initPrune(NULL); } } return NULL; } static sem_t sem_name; char *android::uidToName(uid_t u) { if (!u || !reinit_running) { return NULL; } sem_wait(&sem_name); // Not multi-thread safe, we use sem_name to protect uid = u; name = NULL; sem_post(&reinit); sem_wait(&uidName); char *ret = name; sem_post(&sem_name); return ret; } // Serves as a global method to trigger reinitialization // and as a function that can be provided to signal(). void reinit_signal_handler(int /*signal*/) { sem_post(&reinit); } // tagToName converts an events tag into a name const char *android::tagToName(uint32_t tag) { static const EventTagMap *map; if (!map) { sem_wait(&sem_name); if (!map) { map = android_openEventTagMap(EVENT_TAG_MAP_FILE); } sem_post(&sem_name); if (!map) { return NULL; } } return android_lookupEventTag(map, tag); } static void readDmesg(LogAudit *al, LogKlog *kl) { if (!al && !kl) { return; } int rc = klogctl(KLOG_SIZE_BUFFER, NULL, 0); if (rc <= 0) { return; } size_t len = rc + 1024; // Margin for additional input race or trailing nul std::unique_ptr buf(new char[len]); rc = klogctl(KLOG_READ_ALL, buf.get(), len); if (rc <= 0) { return; } if ((size_t)rc < len) { len = rc + 1; } buf[--len] = '\0'; if (kl && kl->isMonotonic()) { kl->synchronize(buf.get(), len); } size_t sublen; for (char *ptr = NULL, *tok = buf.get(); (rc >= 0) && ((tok = log_strntok_r(tok, &len, &ptr, &sublen))); tok = NULL) { if (al) { rc = al->log(tok, sublen); } if (kl) { rc = kl->log(tok, sublen); } } } // Foreground waits for exit of the main persistent threads // that are started here. The threads are created to manage // UNIX domain client sockets for writing, reading and // controlling the user space logger, and for any additional // logging plugins like auditd and restart control. Additional // transitory per-client threads are created for each reader. int main(int argc, char *argv[]) { int fdPmesg = -1; bool klogd = property_get_bool("logd.kernel", BOOL_DEFAULT_TRUE | BOOL_DEFAULT_FLAG_PERSIST | BOOL_DEFAULT_FLAG_ENG | BOOL_DEFAULT_FLAG_SVELTE); if (klogd) { fdPmesg = open("/proc/kmsg", O_RDONLY | O_NDELAY); } fdDmesg = open("/dev/kmsg", O_WRONLY); // issue reinit command. KISS argument parsing. if ((argc > 1) && argv[1] && !strcmp(argv[1], "--reinit")) { int sock = TEMP_FAILURE_RETRY( socket_local_client("logd", ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_STREAM)); if (sock < 0) { return -errno; } static const char reinit[] = "reinit"; ssize_t ret = TEMP_FAILURE_RETRY(write(sock, reinit, sizeof(reinit))); if (ret < 0) { return -errno; } struct pollfd p; memset(&p, 0, sizeof(p)); p.fd = sock; p.events = POLLIN; ret = TEMP_FAILURE_RETRY(poll(&p, 1, 1000)); if (ret < 0) { return -errno; } if ((ret == 0) || !(p.revents & POLLIN)) { return -ETIME; } static const char success[] = "success"; char buffer[sizeof(success) - 1]; memset(buffer, 0, sizeof(buffer)); ret = TEMP_FAILURE_RETRY(read(sock, buffer, sizeof(buffer))); if (ret < 0) { return -errno; } return strncmp(buffer, success, sizeof(success) - 1) != 0; } // Reinit Thread sem_init(&reinit, 0, 0); sem_init(&uidName, 0, 0); sem_init(&sem_name, 0, 1); pthread_attr_t attr; if (!pthread_attr_init(&attr)) { struct sched_param param; memset(¶m, 0, sizeof(param)); pthread_attr_setschedparam(&attr, ¶m); pthread_attr_setschedpolicy(&attr, SCHED_BATCH); if (!pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED)) { pthread_t thread; reinit_running = true; if (pthread_create(&thread, &attr, reinit_thread_start, NULL)) { reinit_running = false; } } pthread_attr_destroy(&attr); } if (drop_privs() != 0) { return -1; } // Serves the purpose of managing the last logs times read on a // socket connection, and as a reader lock on a range of log // entries. LastLogTimes *times = new LastLogTimes(); // LogBuffer is the object which is responsible for holding all // log entries. logBuf = new LogBuffer(times); signal(SIGHUP, reinit_signal_handler); if (property_get_bool("logd.statistics", BOOL_DEFAULT_TRUE | BOOL_DEFAULT_FLAG_PERSIST | BOOL_DEFAULT_FLAG_ENG | BOOL_DEFAULT_FLAG_SVELTE)) { logBuf->enableStatistics(); } // LogReader listens on /dev/socket/logdr. When a client // connects, log entries in the LogBuffer are written to the client. LogReader *reader = new LogReader(logBuf); if (reader->startListener()) { exit(1); } // LogListener listens on /dev/socket/logdw for client // initiated log messages. New log entries are added to LogBuffer // and LogReader is notified to send updates to connected clients. LogListener *swl = new LogListener(logBuf, reader); // Backlog and /proc/sys/net/unix/max_dgram_qlen set to large value if (swl->startListener(600)) { exit(1); } // Command listener listens on /dev/socket/logd for incoming logd // administrative commands. CommandListener *cl = new CommandListener(logBuf, reader, swl); if (cl->startListener()) { exit(1); } // LogAudit listens on NETLINK_AUDIT socket for selinux // initiated log messages. New log entries are added to LogBuffer // and LogReader is notified to send updates to connected clients. bool auditd = property_get_bool("logd.auditd", BOOL_DEFAULT_TRUE | BOOL_DEFAULT_FLAG_PERSIST); LogAudit *al = NULL; if (auditd) { al = new LogAudit(logBuf, reader, property_get_bool("logd.auditd.dmesg", BOOL_DEFAULT_TRUE | BOOL_DEFAULT_FLAG_PERSIST) ? fdDmesg : -1); } LogKlog *kl = NULL; if (klogd) { kl = new LogKlog(logBuf, reader, fdDmesg, fdPmesg, al != NULL); } readDmesg(al, kl); // failure is an option ... messages are in dmesg (required by standard) if (kl && kl->startListener()) { delete kl; } if (al && al->startListener()) { delete al; } TEMP_FAILURE_RETRY(pause()); exit(0); }