liblog: convert to C++

Bug: 119867234
Test: liblog, logcat, logd unit tests

Change-Id: I2a33b6fc37f9860c0041e3573bfb59ea389f623c
diff --git a/liblog/logd_reader.cpp b/liblog/logd_reader.cpp
new file mode 100644
index 0000000..05bbcbc
--- /dev/null
+++ b/liblog/logd_reader.cpp
@@ -0,0 +1,639 @@
+/*
+ * Copyright (C) 2007-2016 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 <endian.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <poll.h>
+#include <stdarg.h>
+#include <stdatomic.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <cutils/sockets.h>
+#include <private/android_filesystem_config.h>
+#include <private/android_logger.h>
+
+#include "config_read.h"
+#include "log_portability.h"
+#include "logd_reader.h"
+#include "logger.h"
+
+/* branchless on many architectures. */
+#define min(x, y) ((y) ^ (((x) ^ (y)) & -((x) < (y))))
+
+static int logdAvailable(log_id_t LogId);
+static int logdVersion(struct android_log_logger* logger,
+                       struct android_log_transport_context* transp);
+static int logdRead(struct android_log_logger_list* logger_list,
+                    struct android_log_transport_context* transp, struct log_msg* log_msg);
+static int logdPoll(struct android_log_logger_list* logger_list,
+                    struct android_log_transport_context* transp);
+static void logdClose(struct android_log_logger_list* logger_list,
+                      struct android_log_transport_context* transp);
+static int logdClear(struct android_log_logger* logger,
+                     struct android_log_transport_context* transp);
+static ssize_t logdSetSize(struct android_log_logger* logger,
+                           struct android_log_transport_context* transp, size_t size);
+static ssize_t logdGetSize(struct android_log_logger* logger,
+                           struct android_log_transport_context* transp);
+static ssize_t logdGetReadableSize(struct android_log_logger* logger,
+                                   struct android_log_transport_context* transp);
+static ssize_t logdGetPrune(struct android_log_logger_list* logger,
+                            struct android_log_transport_context* transp, char* buf, size_t len);
+static ssize_t logdSetPrune(struct android_log_logger_list* logger,
+                            struct android_log_transport_context* transp, char* buf, size_t len);
+static ssize_t logdGetStats(struct android_log_logger_list* logger,
+                            struct android_log_transport_context* transp, char* buf, size_t len);
+
+LIBLOG_HIDDEN struct android_log_transport_read logdLoggerRead = {
+    .node = {&logdLoggerRead.node, &logdLoggerRead.node},
+    .name = "logd",
+    .available = logdAvailable,
+    .version = logdVersion,
+    .read = logdRead,
+    .poll = logdPoll,
+    .close = logdClose,
+    .clear = logdClear,
+    .getSize = logdGetSize,
+    .setSize = logdSetSize,
+    .getReadableSize = logdGetReadableSize,
+    .getPrune = logdGetPrune,
+    .setPrune = logdSetPrune,
+    .getStats = logdGetStats,
+};
+
+static int logdAvailable(log_id_t logId) {
+  if (logId >= LOG_ID_MAX) {
+    return -EINVAL;
+  }
+  if (logId == LOG_ID_SECURITY) {
+    uid_t uid = __android_log_uid();
+    if (uid != AID_SYSTEM) {
+      return -EPERM;
+    }
+  }
+  if (access("/dev/socket/logdw", W_OK) == 0) {
+    return 0;
+  }
+  return -EBADF;
+}
+
+/* Private copy of ../libcutils/socket_local_client.c prevent library loops */
+
+#if defined(_WIN32)
+
+LIBLOG_WEAK int socket_local_client(const char* name, int namespaceId, int type) {
+  errno = ENOSYS;
+  return -ENOSYS;
+}
+
+#else /* !_WIN32 */
+
+#include <sys/select.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/un.h>
+
+/* Private copy of ../libcutils/socket_local.h prevent library loops */
+#define FILESYSTEM_SOCKET_PREFIX "/tmp/"
+#define ANDROID_RESERVED_SOCKET_PREFIX "/dev/socket/"
+/* End of ../libcutils/socket_local.h */
+
+#define LISTEN_BACKLOG 4
+
+/* Documented in header file. */
+LIBLOG_WEAK int socket_make_sockaddr_un(const char* name, int namespaceId,
+                                        struct sockaddr_un* p_addr, socklen_t* alen) {
+  memset(p_addr, 0, sizeof(*p_addr));
+  size_t namelen;
+
+  switch (namespaceId) {
+    case ANDROID_SOCKET_NAMESPACE_ABSTRACT:
+#if defined(__linux__)
+      namelen = strlen(name);
+
+      /* Test with length +1 for the *initial* '\0'. */
+      if ((namelen + 1) > sizeof(p_addr->sun_path)) {
+        goto error;
+      }
+
+      /*
+       * Note: The path in this case is *not* supposed to be
+       * '\0'-terminated. ("man 7 unix" for the gory details.)
+       */
+
+      p_addr->sun_path[0] = 0;
+      memcpy(p_addr->sun_path + 1, name, namelen);
+#else
+      /* this OS doesn't have the Linux abstract namespace */
+
+      namelen = strlen(name) + strlen(FILESYSTEM_SOCKET_PREFIX);
+      /* unix_path_max appears to be missing on linux */
+      if (namelen > sizeof(*p_addr) - offsetof(struct sockaddr_un, sun_path) - 1) {
+        goto error;
+      }
+
+      strcpy(p_addr->sun_path, FILESYSTEM_SOCKET_PREFIX);
+      strcat(p_addr->sun_path, name);
+#endif
+      break;
+
+    case ANDROID_SOCKET_NAMESPACE_RESERVED:
+      namelen = strlen(name) + strlen(ANDROID_RESERVED_SOCKET_PREFIX);
+      /* unix_path_max appears to be missing on linux */
+      if (namelen > sizeof(*p_addr) - offsetof(struct sockaddr_un, sun_path) - 1) {
+        goto error;
+      }
+
+      strcpy(p_addr->sun_path, ANDROID_RESERVED_SOCKET_PREFIX);
+      strcat(p_addr->sun_path, name);
+      break;
+
+    case ANDROID_SOCKET_NAMESPACE_FILESYSTEM:
+      namelen = strlen(name);
+      /* unix_path_max appears to be missing on linux */
+      if (namelen > sizeof(*p_addr) - offsetof(struct sockaddr_un, sun_path) - 1) {
+        goto error;
+      }
+
+      strcpy(p_addr->sun_path, name);
+      break;
+
+    default:
+      /* invalid namespace id */
+      return -1;
+  }
+
+  p_addr->sun_family = AF_LOCAL;
+  *alen = namelen + offsetof(struct sockaddr_un, sun_path) + 1;
+  return 0;
+error:
+  return -1;
+}
+
+/**
+ * connect to peer named "name" on fd
+ * returns same fd or -1 on error.
+ * fd is not closed on error. that's your job.
+ *
+ * Used by AndroidSocketImpl
+ */
+LIBLOG_WEAK int socket_local_client_connect(int fd, const char* name, int namespaceId,
+                                            int type __unused) {
+  struct sockaddr_un addr;
+  socklen_t alen;
+  int err;
+
+  err = socket_make_sockaddr_un(name, namespaceId, &addr, &alen);
+
+  if (err < 0) {
+    goto error;
+  }
+
+  if (connect(fd, (struct sockaddr*)&addr, alen) < 0) {
+    goto error;
+  }
+
+  return fd;
+
+error:
+  return -1;
+}
+
+/**
+ * connect to peer named "name"
+ * returns fd or -1 on error
+ */
+LIBLOG_WEAK int socket_local_client(const char* name, int namespaceId, int type) {
+  int s;
+
+  s = socket(AF_LOCAL, type, 0);
+  if (s < 0) return -1;
+
+  if (0 > socket_local_client_connect(s, name, namespaceId, type)) {
+    close(s);
+    return -1;
+  }
+
+  return s;
+}
+
+#endif /* !_WIN32 */
+/* End of ../libcutils/socket_local_client.c */
+
+/* worker for sending the command to the logger */
+static ssize_t send_log_msg(struct android_log_logger* logger, const char* msg, char* buf,
+                            size_t buf_size) {
+  ssize_t ret;
+  size_t len;
+  char* cp;
+  int errno_save = 0;
+  int sock = socket_local_client("logd", ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_STREAM);
+  if (sock < 0) {
+    return sock;
+  }
+
+  if (msg) {
+    snprintf(buf, buf_size, msg, logger ? logger->logId : (unsigned)-1);
+  }
+
+  len = strlen(buf) + 1;
+  ret = TEMP_FAILURE_RETRY(write(sock, buf, len));
+  if (ret <= 0) {
+    goto done;
+  }
+
+  len = buf_size;
+  cp = buf;
+  while ((ret = TEMP_FAILURE_RETRY(read(sock, cp, len))) > 0) {
+    struct pollfd p;
+
+    if (((size_t)ret == len) || (buf_size < PAGE_SIZE)) {
+      break;
+    }
+
+    len -= ret;
+    cp += ret;
+
+    memset(&p, 0, sizeof(p));
+    p.fd = sock;
+    p.events = POLLIN;
+
+    /* Give other side 20ms to refill pipe */
+    ret = TEMP_FAILURE_RETRY(poll(&p, 1, 20));
+
+    if (ret <= 0) {
+      break;
+    }
+
+    if (!(p.revents & POLLIN)) {
+      ret = 0;
+      break;
+    }
+  }
+
+  if (ret >= 0) {
+    ret += buf_size - len;
+  }
+
+done:
+  if ((ret == -1) && errno) {
+    errno_save = errno;
+  }
+  close(sock);
+  if (errno_save) {
+    errno = errno_save;
+  }
+  return ret;
+}
+
+LIBLOG_HIDDEN ssize_t __send_log_msg(char* buf, size_t buf_size) {
+  return send_log_msg(NULL, NULL, buf, buf_size);
+}
+
+static int check_log_success(char* buf, ssize_t ret) {
+  if (ret < 0) {
+    return ret;
+  }
+
+  if (strncmp(buf, "success", 7)) {
+    errno = EINVAL;
+    return -1;
+  }
+
+  return 0;
+}
+
+static int logdClear(struct android_log_logger* logger,
+                     struct android_log_transport_context* transp __unused) {
+  char buf[512];
+
+  return check_log_success(buf, send_log_msg(logger, "clear %d", buf, sizeof(buf)));
+}
+
+/* returns the total size of the log's ring buffer */
+static ssize_t logdGetSize(struct android_log_logger* logger,
+                           struct android_log_transport_context* transp __unused) {
+  char buf[512];
+
+  ssize_t ret = send_log_msg(logger, "getLogSize %d", buf, sizeof(buf));
+  if (ret < 0) {
+    return ret;
+  }
+
+  if ((buf[0] < '0') || ('9' < buf[0])) {
+    return -1;
+  }
+
+  return atol(buf);
+}
+
+static ssize_t logdSetSize(struct android_log_logger* logger,
+                           struct android_log_transport_context* transp __unused, size_t size) {
+  char buf[512];
+
+  snprintf(buf, sizeof(buf), "setLogSize %d %zu", logger->logId, size);
+
+  return check_log_success(buf, send_log_msg(NULL, NULL, buf, sizeof(buf)));
+}
+
+/*
+ * returns the readable size of the log's ring buffer (that is, amount of the
+ * log consumed)
+ */
+static ssize_t logdGetReadableSize(struct android_log_logger* logger,
+                                   struct android_log_transport_context* transp __unused) {
+  char buf[512];
+
+  ssize_t ret = send_log_msg(logger, "getLogSizeUsed %d", buf, sizeof(buf));
+  if (ret < 0) {
+    return ret;
+  }
+
+  if ((buf[0] < '0') || ('9' < buf[0])) {
+    return -1;
+  }
+
+  return atol(buf);
+}
+
+/*
+ * returns the logger version
+ */
+static int logdVersion(struct android_log_logger* logger __unused,
+                       struct android_log_transport_context* transp __unused) {
+  uid_t uid = __android_log_uid();
+  return ((uid != AID_ROOT) && (uid != AID_LOG) && (uid != AID_SYSTEM)) ? 3 : 4;
+}
+
+/*
+ * returns statistics
+ */
+static ssize_t logdGetStats(struct android_log_logger_list* logger_list,
+                            struct android_log_transport_context* transp __unused, char* buf,
+                            size_t len) {
+  struct android_log_logger* logger;
+  char* cp = buf;
+  size_t remaining = len;
+  size_t n;
+
+  n = snprintf(cp, remaining, "getStatistics");
+  n = min(n, remaining);
+  remaining -= n;
+  cp += n;
+
+  logger_for_each(logger, logger_list) {
+    n = snprintf(cp, remaining, " %d", logger->logId);
+    n = min(n, remaining);
+    remaining -= n;
+    cp += n;
+  }
+
+  if (logger_list->pid) {
+    snprintf(cp, remaining, " pid=%u", logger_list->pid);
+  }
+
+  return send_log_msg(NULL, NULL, buf, len);
+}
+
+static ssize_t logdGetPrune(struct android_log_logger_list* logger_list __unused,
+                            struct android_log_transport_context* transp __unused, char* buf,
+                            size_t len) {
+  return send_log_msg(NULL, "getPruneList", buf, len);
+}
+
+static ssize_t logdSetPrune(struct android_log_logger_list* logger_list __unused,
+                            struct android_log_transport_context* transp __unused, char* buf,
+                            size_t len) {
+  const char cmd[] = "setPruneList ";
+  const size_t cmdlen = sizeof(cmd) - 1;
+
+  if (strlen(buf) > (len - cmdlen)) {
+    return -ENOMEM; /* KISS */
+  }
+  memmove(buf + cmdlen, buf, len - cmdlen);
+  buf[len - 1] = '\0';
+  memcpy(buf, cmd, cmdlen);
+
+  return check_log_success(buf, send_log_msg(NULL, NULL, buf, len));
+}
+
+static void caught_signal(int signum __unused) {}
+
+static int logdOpen(struct android_log_logger_list* logger_list,
+                    struct android_log_transport_context* transp) {
+  struct android_log_logger* logger;
+  struct sigaction ignore;
+  struct sigaction old_sigaction;
+  unsigned int old_alarm = 0;
+  char buffer[256], *cp, c;
+  int e, ret, remaining, sock;
+
+  if (!logger_list) {
+    return -EINVAL;
+  }
+
+  sock = atomic_load(&transp->context.sock);
+  if (sock > 0) {
+    return sock;
+  }
+
+  sock = socket_local_client("logdr", ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_SEQPACKET);
+  if (sock == 0) {
+    /* Guarantee not file descriptor zero */
+    int newsock = socket_local_client("logdr", ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_SEQPACKET);
+    close(sock);
+    sock = newsock;
+  }
+  if (sock <= 0) {
+    if ((sock == -1) && errno) {
+      return -errno;
+    }
+    return sock;
+  }
+
+  strcpy(buffer, (logger_list->mode & ANDROID_LOG_NONBLOCK) ? "dumpAndClose" : "stream");
+  cp = buffer + strlen(buffer);
+
+  strcpy(cp, " lids");
+  cp += 5;
+  c = '=';
+  remaining = sizeof(buffer) - (cp - buffer);
+  logger_for_each(logger, logger_list) {
+    ret = snprintf(cp, remaining, "%c%u", c, logger->logId);
+    ret = min(ret, remaining);
+    remaining -= ret;
+    cp += ret;
+    c = ',';
+  }
+
+  if (logger_list->tail) {
+    ret = snprintf(cp, remaining, " tail=%u", logger_list->tail);
+    ret = min(ret, remaining);
+    remaining -= ret;
+    cp += ret;
+  }
+
+  if (logger_list->start.tv_sec || logger_list->start.tv_nsec) {
+    if (logger_list->mode & ANDROID_LOG_WRAP) {
+      // ToDo: alternate API to allow timeout to be adjusted.
+      ret = snprintf(cp, remaining, " timeout=%u", ANDROID_LOG_WRAP_DEFAULT_TIMEOUT);
+      ret = min(ret, remaining);
+      remaining -= ret;
+      cp += ret;
+    }
+    ret = snprintf(cp, remaining, " start=%" PRIu32 ".%09" PRIu32, logger_list->start.tv_sec,
+                   logger_list->start.tv_nsec);
+    ret = min(ret, remaining);
+    remaining -= ret;
+    cp += ret;
+  }
+
+  if (logger_list->pid) {
+    ret = snprintf(cp, remaining, " pid=%u", logger_list->pid);
+    ret = min(ret, remaining);
+    cp += ret;
+  }
+
+  if (logger_list->mode & ANDROID_LOG_NONBLOCK) {
+    /* Deal with an unresponsive logd */
+    memset(&ignore, 0, sizeof(ignore));
+    ignore.sa_handler = caught_signal;
+    sigemptyset(&ignore.sa_mask);
+    /* particularily useful if tombstone is reporting for logd */
+    sigaction(SIGALRM, &ignore, &old_sigaction);
+    old_alarm = alarm(30);
+  }
+  ret = write(sock, buffer, cp - buffer);
+  e = errno;
+  if (logger_list->mode & ANDROID_LOG_NONBLOCK) {
+    if (e == EINTR) {
+      e = ETIMEDOUT;
+    }
+    alarm(old_alarm);
+    sigaction(SIGALRM, &old_sigaction, NULL);
+  }
+
+  if (ret <= 0) {
+    close(sock);
+    if ((ret == -1) && e) {
+      return -e;
+    }
+    if (ret == 0) {
+      return -EIO;
+    }
+    return ret;
+  }
+
+  ret = atomic_exchange(&transp->context.sock, sock);
+  if ((ret > 0) && (ret != sock)) {
+    close(ret);
+  }
+  return sock;
+}
+
+/* Read from the selected logs */
+static int logdRead(struct android_log_logger_list* logger_list,
+                    struct android_log_transport_context* transp, struct log_msg* log_msg) {
+  int ret, e;
+  struct sigaction ignore;
+  struct sigaction old_sigaction;
+  unsigned int old_alarm = 0;
+
+  ret = logdOpen(logger_list, transp);
+  if (ret < 0) {
+    return ret;
+  }
+
+  memset(log_msg, 0, sizeof(*log_msg));
+
+  unsigned int new_alarm = 0;
+  if (logger_list->mode & ANDROID_LOG_NONBLOCK) {
+    if ((logger_list->mode & ANDROID_LOG_WRAP) &&
+        (logger_list->start.tv_sec || logger_list->start.tv_nsec)) {
+      /* b/64143705 */
+      new_alarm = (ANDROID_LOG_WRAP_DEFAULT_TIMEOUT * 11) / 10 + 10;
+      logger_list->mode &= ~ANDROID_LOG_WRAP;
+    } else {
+      new_alarm = 30;
+    }
+
+    memset(&ignore, 0, sizeof(ignore));
+    ignore.sa_handler = caught_signal;
+    sigemptyset(&ignore.sa_mask);
+    /* particularily useful if tombstone is reporting for logd */
+    sigaction(SIGALRM, &ignore, &old_sigaction);
+    old_alarm = alarm(new_alarm);
+  }
+
+  /* NOTE: SOCK_SEQPACKET guarantees we read exactly one full entry */
+  ret = recv(ret, log_msg, LOGGER_ENTRY_MAX_LEN, 0);
+  e = errno;
+
+  if (new_alarm) {
+    if ((ret == 0) || (e == EINTR)) {
+      e = EAGAIN;
+      ret = -1;
+    }
+    alarm(old_alarm);
+    sigaction(SIGALRM, &old_sigaction, NULL);
+  }
+
+  if ((ret == -1) && e) {
+    return -e;
+  }
+  return ret;
+}
+
+static int logdPoll(struct android_log_logger_list* logger_list,
+                    struct android_log_transport_context* transp) {
+  struct pollfd p;
+
+  int ret = logdOpen(logger_list, transp);
+  if (ret < 0) {
+    return ret;
+  }
+
+  memset(&p, 0, sizeof(p));
+  p.fd = ret;
+  p.events = POLLIN;
+  ret = poll(&p, 1, 20);
+  if ((ret > 0) && !(p.revents & POLLIN)) {
+    ret = 0;
+  }
+  if ((ret == -1) && errno) {
+    return -errno;
+  }
+  return ret;
+}
+
+/* Close all the logs */
+static void logdClose(struct android_log_logger_list* logger_list __unused,
+                      struct android_log_transport_context* transp) {
+  int sock = atomic_exchange(&transp->context.sock, -1);
+  if (sock > 0) {
+    close(sock);
+  }
+}