liblog: convert to C++

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

Change-Id: I2a33b6fc37f9860c0041e3573bfb59ea389f623c
diff --git a/liblog/pmsg_reader.cpp b/liblog/pmsg_reader.cpp
new file mode 100644
index 0000000..7bc6e4a
--- /dev/null
+++ b/liblog/pmsg_reader.cpp
@@ -0,0 +1,591 @@
+/*
+ * 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 <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include <private/android_filesystem_config.h>
+#include <private/android_logger.h>
+
+#include "config_read.h"
+#include "logger.h"
+
+static int pmsgAvailable(log_id_t logId);
+static int pmsgVersion(struct android_log_logger* logger,
+                       struct android_log_transport_context* transp);
+static int pmsgRead(struct android_log_logger_list* logger_list,
+                    struct android_log_transport_context* transp, struct log_msg* log_msg);
+static void pmsgClose(struct android_log_logger_list* logger_list,
+                      struct android_log_transport_context* transp);
+static int pmsgClear(struct android_log_logger* logger,
+                     struct android_log_transport_context* transp);
+
+LIBLOG_HIDDEN struct android_log_transport_read pmsgLoggerRead = {
+    .node = {&pmsgLoggerRead.node, &pmsgLoggerRead.node},
+    .name = "pmsg",
+    .available = pmsgAvailable,
+    .version = pmsgVersion,
+    .read = pmsgRead,
+    .poll = NULL,
+    .close = pmsgClose,
+    .clear = pmsgClear,
+    .setSize = NULL,
+    .getSize = NULL,
+    .getReadableSize = NULL,
+    .getPrune = NULL,
+    .setPrune = NULL,
+    .getStats = NULL,
+};
+
+static int pmsgAvailable(log_id_t logId) {
+  if (logId > LOG_ID_SECURITY) {
+    return -EINVAL;
+  }
+  if (access("/dev/pmsg0", W_OK) == 0) {
+    return 0;
+  }
+  return -EBADF;
+}
+
+/* Determine the credentials of the caller */
+static bool uid_has_log_permission(uid_t uid) {
+  return (uid == AID_SYSTEM) || (uid == AID_LOG) || (uid == AID_ROOT) || (uid == AID_LOGD);
+}
+
+static uid_t get_best_effective_uid() {
+  uid_t euid;
+  uid_t uid;
+  gid_t gid;
+  ssize_t i;
+  static uid_t last_uid = (uid_t)-1;
+
+  if (last_uid != (uid_t)-1) {
+    return last_uid;
+  }
+  uid = __android_log_uid();
+  if (uid_has_log_permission(uid)) {
+    return last_uid = uid;
+  }
+  euid = geteuid();
+  if (uid_has_log_permission(euid)) {
+    return last_uid = euid;
+  }
+  gid = getgid();
+  if (uid_has_log_permission(gid)) {
+    return last_uid = gid;
+  }
+  gid = getegid();
+  if (uid_has_log_permission(gid)) {
+    return last_uid = gid;
+  }
+  i = getgroups((size_t)0, NULL);
+  if (i > 0) {
+    gid_t list[i];
+
+    getgroups(i, list);
+    while (--i >= 0) {
+      if (uid_has_log_permission(list[i])) {
+        return last_uid = list[i];
+      }
+    }
+  }
+  return last_uid = uid;
+}
+
+static int pmsgClear(struct android_log_logger* logger __unused,
+                     struct android_log_transport_context* transp __unused) {
+  if (uid_has_log_permission(get_best_effective_uid())) {
+    return unlink("/sys/fs/pstore/pmsg-ramoops-0");
+  }
+  errno = EPERM;
+  return -1;
+}
+
+/*
+ * returns the logger version
+ */
+static int pmsgVersion(struct android_log_logger* logger __unused,
+                       struct android_log_transport_context* transp __unused) {
+  return 4;
+}
+
+static int pmsgRead(struct android_log_logger_list* logger_list,
+                    struct android_log_transport_context* transp, struct log_msg* log_msg) {
+  ssize_t ret;
+  off_t current, next;
+  uid_t uid;
+  struct android_log_logger* logger;
+  struct __attribute__((__packed__)) {
+    android_pmsg_log_header_t p;
+    android_log_header_t l;
+    uint8_t prio;
+  } buf;
+  static uint8_t preread_count;
+  bool is_system;
+
+  memset(log_msg, 0, sizeof(*log_msg));
+
+  if (atomic_load(&transp->context.fd) <= 0) {
+    int i, fd = open("/sys/fs/pstore/pmsg-ramoops-0", O_RDONLY | O_CLOEXEC);
+
+    if (fd < 0) {
+      return -errno;
+    }
+    if (fd == 0) { /* Argggg */
+      fd = open("/sys/fs/pstore/pmsg-ramoops-0", O_RDONLY | O_CLOEXEC);
+      close(0);
+      if (fd < 0) {
+        return -errno;
+      }
+    }
+    i = atomic_exchange(&transp->context.fd, fd);
+    if ((i > 0) && (i != fd)) {
+      close(i);
+    }
+    preread_count = 0;
+  }
+
+  while (1) {
+    int fd;
+
+    if (preread_count < sizeof(buf)) {
+      fd = atomic_load(&transp->context.fd);
+      if (fd <= 0) {
+        return -EBADF;
+      }
+      ret = TEMP_FAILURE_RETRY(read(fd, &buf.p.magic + preread_count, sizeof(buf) - preread_count));
+      if (ret < 0) {
+        return -errno;
+      }
+      preread_count += ret;
+    }
+    if (preread_count != sizeof(buf)) {
+      return preread_count ? -EIO : -EAGAIN;
+    }
+    if ((buf.p.magic != LOGGER_MAGIC) || (buf.p.len <= sizeof(buf)) ||
+        (buf.p.len > (sizeof(buf) + LOGGER_ENTRY_MAX_PAYLOAD)) || (buf.l.id >= LOG_ID_MAX) ||
+        (buf.l.realtime.tv_nsec >= NS_PER_SEC) ||
+        ((buf.l.id != LOG_ID_EVENTS) && (buf.l.id != LOG_ID_SECURITY) &&
+         ((buf.prio == ANDROID_LOG_UNKNOWN) || (buf.prio == ANDROID_LOG_DEFAULT) ||
+          (buf.prio >= ANDROID_LOG_SILENT)))) {
+      do {
+        memmove(&buf.p.magic, &buf.p.magic + 1, --preread_count);
+      } while (preread_count && (buf.p.magic != LOGGER_MAGIC));
+      continue;
+    }
+    preread_count = 0;
+
+    if ((transp->logMask & (1 << buf.l.id)) &&
+        ((!logger_list->start.tv_sec && !logger_list->start.tv_nsec) ||
+         ((logger_list->start.tv_sec <= buf.l.realtime.tv_sec) &&
+          ((logger_list->start.tv_sec != buf.l.realtime.tv_sec) ||
+           (logger_list->start.tv_nsec <= buf.l.realtime.tv_nsec)))) &&
+        (!logger_list->pid || (logger_list->pid == buf.p.pid))) {
+      uid = get_best_effective_uid();
+      is_system = uid_has_log_permission(uid);
+      if (is_system || (uid == buf.p.uid)) {
+        char* msg = is_system ? log_msg->entry_v4.msg : log_msg->entry_v3.msg;
+        *msg = buf.prio;
+        fd = atomic_load(&transp->context.fd);
+        if (fd <= 0) {
+          return -EBADF;
+        }
+        ret = TEMP_FAILURE_RETRY(read(fd, msg + sizeof(buf.prio), buf.p.len - sizeof(buf)));
+        if (ret < 0) {
+          return -errno;
+        }
+        if (ret != (ssize_t)(buf.p.len - sizeof(buf))) {
+          return -EIO;
+        }
+
+        log_msg->entry_v4.len = buf.p.len - sizeof(buf) + sizeof(buf.prio);
+        log_msg->entry_v4.hdr_size =
+            is_system ? sizeof(log_msg->entry_v4) : sizeof(log_msg->entry_v3);
+        log_msg->entry_v4.pid = buf.p.pid;
+        log_msg->entry_v4.tid = buf.l.tid;
+        log_msg->entry_v4.sec = buf.l.realtime.tv_sec;
+        log_msg->entry_v4.nsec = buf.l.realtime.tv_nsec;
+        log_msg->entry_v4.lid = buf.l.id;
+        if (is_system) {
+          log_msg->entry_v4.uid = buf.p.uid;
+        }
+
+        return ret + sizeof(buf.prio) + log_msg->entry_v4.hdr_size;
+      }
+    }
+
+    fd = atomic_load(&transp->context.fd);
+    if (fd <= 0) {
+      return -EBADF;
+    }
+    current = TEMP_FAILURE_RETRY(lseek(fd, (off_t)0, SEEK_CUR));
+    if (current < 0) {
+      return -errno;
+    }
+    fd = atomic_load(&transp->context.fd);
+    if (fd <= 0) {
+      return -EBADF;
+    }
+    next = TEMP_FAILURE_RETRY(lseek(fd, (off_t)(buf.p.len - sizeof(buf)), SEEK_CUR));
+    if (next < 0) {
+      return -errno;
+    }
+    if ((next - current) != (ssize_t)(buf.p.len - sizeof(buf))) {
+      return -EIO;
+    }
+  }
+}
+
+static void pmsgClose(struct android_log_logger_list* logger_list __unused,
+                      struct android_log_transport_context* transp) {
+  int fd = atomic_exchange(&transp->context.fd, 0);
+  if (fd > 0) {
+    close(fd);
+  }
+}
+
+static void* realloc_or_free(void* ptr, size_t new_size) {
+  void* result = realloc(ptr, new_size);
+  if (!result) {
+    free(ptr);
+  }
+  return result;
+}
+
+LIBLOG_ABI_PRIVATE ssize_t __android_log_pmsg_file_read(log_id_t logId, char prio,
+                                                        const char* prefix,
+                                                        __android_log_pmsg_file_read_fn fn,
+                                                        void* arg) {
+  ssize_t ret;
+  struct android_log_logger_list logger_list;
+  struct android_log_transport_context transp;
+  struct content {
+    struct listnode node;
+    union {
+      struct logger_entry_v4 entry;
+      struct logger_entry_v4 entry_v4;
+      struct logger_entry_v3 entry_v3;
+      struct logger_entry_v2 entry_v2;
+      struct logger_entry entry_v1;
+    };
+  } * content;
+  struct names {
+    struct listnode node;
+    struct listnode content;
+    log_id_t id;
+    char prio;
+    char name[];
+  } * names;
+  struct listnode name_list;
+  struct listnode *node, *n;
+  size_t len, prefix_len;
+
+  if (!fn) {
+    return -EINVAL;
+  }
+
+  /* Add just enough clues in logger_list and transp to make API function */
+  memset(&logger_list, 0, sizeof(logger_list));
+  memset(&transp, 0, sizeof(transp));
+
+  logger_list.mode = ANDROID_LOG_PSTORE | ANDROID_LOG_NONBLOCK | ANDROID_LOG_RDONLY;
+  transp.logMask = (unsigned)-1;
+  if (logId != LOG_ID_ANY) {
+    transp.logMask = (1 << logId);
+  }
+  transp.logMask &= ~((1 << LOG_ID_KERNEL) | (1 << LOG_ID_EVENTS) | (1 << LOG_ID_SECURITY));
+  if (!transp.logMask) {
+    return -EINVAL;
+  }
+
+  /* Initialize name list */
+  list_init(&name_list);
+
+  ret = SSIZE_MAX;
+
+  /* Validate incoming prefix, shift until it contains only 0 or 1 : or / */
+  prefix_len = 0;
+  if (prefix) {
+    const char *prev = NULL, *last = NULL, *cp = prefix;
+    while ((cp = strpbrk(cp, "/:"))) {
+      prev = last;
+      last = cp;
+      cp = cp + 1;
+    }
+    if (prev) {
+      prefix = prev + 1;
+    }
+    prefix_len = strlen(prefix);
+  }
+
+  /* Read the file content */
+  while (pmsgRead(&logger_list, &transp, &transp.logMsg) > 0) {
+    const char* cp;
+    size_t hdr_size = transp.logMsg.entry.hdr_size ? transp.logMsg.entry.hdr_size
+                                                   : sizeof(transp.logMsg.entry_v1);
+    char* msg = (char*)&transp.logMsg + hdr_size;
+    const char* split = NULL;
+
+    if ((hdr_size < sizeof(transp.logMsg.entry_v1)) || (hdr_size > sizeof(transp.logMsg.entry))) {
+      continue;
+    }
+    /* Check for invalid sequence number */
+    if ((transp.logMsg.entry.nsec % ANDROID_LOG_PMSG_FILE_SEQUENCE) ||
+        ((transp.logMsg.entry.nsec / ANDROID_LOG_PMSG_FILE_SEQUENCE) >=
+         ANDROID_LOG_PMSG_FILE_MAX_SEQUENCE)) {
+      continue;
+    }
+
+    /* Determine if it has <dirbase>:<filebase> format for tag */
+    len = transp.logMsg.entry.len - sizeof(prio);
+    for (cp = msg + sizeof(prio); *cp && isprint(*cp) && !isspace(*cp) && --len; ++cp) {
+      if (*cp == ':') {
+        if (split) {
+          break;
+        }
+        split = cp;
+      }
+    }
+    if (*cp || !split) {
+      continue;
+    }
+
+    /* Filters */
+    if (prefix_len && strncmp(msg + sizeof(prio), prefix, prefix_len)) {
+      size_t offset;
+      /*
+       *   Allow : to be a synonym for /
+       * Things we do dealing with const char * and do not alloc
+       */
+      split = strchr(prefix, ':');
+      if (split) {
+        continue;
+      }
+      split = strchr(prefix, '/');
+      if (!split) {
+        continue;
+      }
+      offset = split - prefix;
+      if ((msg[offset + sizeof(prio)] != ':') || strncmp(msg + sizeof(prio), prefix, offset)) {
+        continue;
+      }
+      ++offset;
+      if ((prefix_len > offset) &&
+          strncmp(&msg[offset + sizeof(prio)], split + 1, prefix_len - offset)) {
+        continue;
+      }
+    }
+
+    if ((prio != ANDROID_LOG_ANY) && (*msg < prio)) {
+      continue;
+    }
+
+    /* check if there is an existing entry */
+    list_for_each(node, &name_list) {
+      names = node_to_item(node, struct names, node);
+      if (!strcmp(names->name, msg + sizeof(prio)) && (names->id == transp.logMsg.entry.lid) &&
+          (names->prio == *msg)) {
+        break;
+      }
+    }
+
+    /* We do not have an existing entry, create and add one */
+    if (node == &name_list) {
+      static const char numbers[] = "0123456789";
+      unsigned long long nl;
+
+      len = strlen(msg + sizeof(prio)) + 1;
+      names = static_cast<struct names*>(calloc(1, sizeof(*names) + len));
+      if (!names) {
+        ret = -ENOMEM;
+        break;
+      }
+      strcpy(names->name, msg + sizeof(prio));
+      names->id = static_cast<log_id_t>(transp.logMsg.entry.lid);
+      names->prio = *msg;
+      list_init(&names->content);
+      /*
+       * Insert in reverse numeric _then_ alpha sorted order as
+       * representative of log rotation:
+       *
+       *   log.10
+       *   klog.10
+       *   . . .
+       *   log.2
+       *   klog.2
+       *   log.1
+       *   klog.1
+       *   log
+       *   klog
+       *
+       * thus when we present the content, we are provided the oldest
+       * first, which when 'refreshed' could spill off the end of the
+       * pmsg FIFO but retaining the newest data for last with best
+       * chances to survive.
+       */
+      nl = 0;
+      cp = strpbrk(names->name, numbers);
+      if (cp) {
+        nl = strtoull(cp, NULL, 10);
+      }
+      list_for_each_reverse(node, &name_list) {
+        struct names* a_name = node_to_item(node, struct names, node);
+        const char* r = a_name->name;
+        int compare = 0;
+
+        unsigned long long nr = 0;
+        cp = strpbrk(r, numbers);
+        if (cp) {
+          nr = strtoull(cp, NULL, 10);
+        }
+        if (nr != nl) {
+          compare = (nl > nr) ? 1 : -1;
+        }
+        if (compare == 0) {
+          compare = strcmp(names->name, r);
+        }
+        if (compare <= 0) {
+          break;
+        }
+      }
+      list_add_head(node, &names->node);
+    }
+
+    /* Remove any file fragments that match our sequence number */
+    list_for_each_safe(node, n, &names->content) {
+      content = node_to_item(node, struct content, node);
+      if (transp.logMsg.entry.nsec == content->entry.nsec) {
+        list_remove(&content->node);
+        free(content);
+      }
+    }
+
+    /* Add content */
+    content = static_cast<struct content*>(
+        calloc(1, sizeof(content->node) + hdr_size + transp.logMsg.entry.len));
+    if (!content) {
+      ret = -ENOMEM;
+      break;
+    }
+    memcpy(&content->entry, &transp.logMsg.entry, hdr_size + transp.logMsg.entry.len);
+
+    /* Insert in sequence number sorted order, to ease reconstruction */
+    list_for_each_reverse(node, &names->content) {
+      if ((node_to_item(node, struct content, node))->entry.nsec < transp.logMsg.entry.nsec) {
+        break;
+      }
+    }
+    list_add_head(node, &content->node);
+  }
+  pmsgClose(&logger_list, &transp);
+
+  /* Progress through all the collected files */
+  list_for_each_safe(node, n, &name_list) {
+    struct listnode *content_node, *m;
+    char* buf;
+    size_t sequence, tag_len;
+
+    names = node_to_item(node, struct names, node);
+
+    /* Construct content into a linear buffer */
+    buf = NULL;
+    len = 0;
+    sequence = 0;
+    tag_len = strlen(names->name) + sizeof(char); /* tag + nul */
+    list_for_each_safe(content_node, m, &names->content) {
+      ssize_t add_len;
+
+      content = node_to_item(content_node, struct content, node);
+      add_len = content->entry.len - tag_len - sizeof(prio);
+      if (add_len <= 0) {
+        list_remove(content_node);
+        free(content);
+        continue;
+      }
+
+      if (!buf) {
+        buf = static_cast<char*>(malloc(sizeof(char)));
+        if (!buf) {
+          ret = -ENOMEM;
+          list_remove(content_node);
+          free(content);
+          continue;
+        }
+        *buf = '\0';
+      }
+
+      /* Missing sequence numbers */
+      while (sequence < content->entry.nsec) {
+        /* plus space for enforced nul */
+        buf = static_cast<char*>(realloc_or_free(buf, len + sizeof(char) + sizeof(char)));
+        if (!buf) {
+          break;
+        }
+        buf[len] = '\f'; /* Mark missing content with a form feed */
+        buf[++len] = '\0';
+        sequence += ANDROID_LOG_PMSG_FILE_SEQUENCE;
+      }
+      if (!buf) {
+        ret = -ENOMEM;
+        list_remove(content_node);
+        free(content);
+        continue;
+      }
+      /* plus space for enforced nul */
+      buf = static_cast<char*>(realloc_or_free(buf, len + add_len + sizeof(char)));
+      if (!buf) {
+        ret = -ENOMEM;
+        list_remove(content_node);
+        free(content);
+        continue;
+      }
+      memcpy(buf + len, (char*)&content->entry + content->entry.hdr_size + tag_len + sizeof(prio),
+             add_len);
+      len += add_len;
+      buf[len] = '\0'; /* enforce trailing hidden nul */
+      sequence = content->entry.nsec + ANDROID_LOG_PMSG_FILE_SEQUENCE;
+
+      list_remove(content_node);
+      free(content);
+    }
+    if (buf) {
+      if (len) {
+        /* Buffer contains enforced trailing nul just beyond length */
+        ssize_t r;
+        *strchr(names->name, ':') = '/'; /* Convert back to filename */
+        r = (*fn)(names->id, names->prio, names->name, buf, len, arg);
+        if ((ret >= 0) && (r > 0)) {
+          if (ret == SSIZE_MAX) {
+            ret = r;
+          } else {
+            ret += r;
+          }
+        } else if (r < ret) {
+          ret = r;
+        }
+      }
+      free(buf);
+    }
+    list_remove(node);
+    free(names);
+  }
+  return (ret == SSIZE_MAX) ? -ENOENT : ret;
+}