liblog: enable logging to logd.

* Modify liblog to send all messages to the new syslog user
  space daemon.

Original-Change-Id: I0ce439738cd921efb2db4c1d6a289a96bdbc8bc2
Original-Change-Id: If4eb0d09409f7e9be3eb4bb7017073dc7e931ab4
Signed-off-by: Nick Kralevich <nnk@google.com>

* Add a TARGET_USES_LOGD make flag for BoardConfig.mk to manage
  whether logd is enabled for use or not.
* rename syslog to logd to avert confusion with bionic syslog
* Add fake log support back in
* prefilter for logging messages from logd
* Fill in timestamps at logging source
* update abstract log reader
* switch from using suffix for id to v3 format
* log a message when creating devices that a deprecated interface
  is being utilized.

Signed-off-by: Mark Salyzyn <salyzyn@google.com>

(cherry pick from commit 099e2c1f6f706a8600c1cef74cce9066fc315480)

Change-Id: I47929a5432977a1d7235267a435cec0a7d6bd440

1 files changed, 695 insertions, 0 deletions

diff --git a/liblog/log_read_kern.c b/liblog/log_read_kern.c
new file mode 100644
index 0000000..b454729
--- /dev/null
+++ b/liblog/log_read_kern.c
@@ -0,0 +1,695 @@
+/*
+** Copyright 2013-2014, 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.
+*/
+
+#define _GNU_SOURCE /* asprintf for x86 host */
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <cutils/list.h>
+#include <log/log.h>
+#include <log/logger.h>
+
+#include <sys/ioctl.h>
+
+#define __LOGGERIO     0xAE
+
+#define LOGGER_GET_LOG_BUF_SIZE    _IO(__LOGGERIO, 1) /* size of log */
+#define LOGGER_GET_LOG_LEN         _IO(__LOGGERIO, 2) /* used log len */
+#define LOGGER_GET_NEXT_ENTRY_LEN  _IO(__LOGGERIO, 3) /* next entry len */
+#define LOGGER_FLUSH_LOG           _IO(__LOGGERIO, 4) /* flush log */
+#define LOGGER_GET_VERSION         _IO(__LOGGERIO, 5) /* abi version */
+#define LOGGER_SET_VERSION         _IO(__LOGGERIO, 6) /* abi version */
+
+typedef char bool;
+#define false (const bool)0
+#define true (const bool)1
+
+#define LOG_FILE_DIR "/dev/log/"
+
+/* timeout in milliseconds */
+#define LOG_TIMEOUT_FLUSH 5
+#define LOG_TIMEOUT_NEVER -1
+
+#define logger_for_each(logger, logger_list) \
+    for (logger = node_to_item((logger_list)->node.next, struct logger, node); \
+         logger != node_to_item(&(logger_list)->node, struct logger, node); \
+         logger = node_to_item((logger)->node.next, struct logger, node))
+
+/* In the future, we would like to make this list extensible */
+static const char *LOG_NAME[LOG_ID_MAX] = {
+    [LOG_ID_MAIN] = "main",
+    [LOG_ID_RADIO] = "radio",
+    [LOG_ID_EVENTS] = "events",
+    [LOG_ID_SYSTEM] = "system"
+};
+
+const char *android_log_id_to_name(log_id_t log_id)
+{
+    if (log_id >= LOG_ID_MAX) {
+        log_id = LOG_ID_MAIN;
+    }
+    return LOG_NAME[log_id];
+}
+
+static int accessmode(int mode)
+{
+    if ((mode & O_ACCMODE) == O_WRONLY) {
+        return W_OK;
+    }
+    if ((mode & O_ACCMODE) == O_RDWR) {
+        return R_OK | W_OK;
+    }
+    return R_OK;
+}
+
+/* repeated fragment */
+static int check_allocate_accessible(char **n, const char *b, int mode)
+{
+    *n = NULL;
+
+    if (!b) {
+        return -EINVAL;
+    }
+
+    asprintf(n, LOG_FILE_DIR "%s", b);
+    if (!*n) {
+        return -1;
+    }
+
+    return access(*n, accessmode(mode));
+}
+
+log_id_t android_name_to_log_id(const char *logName)
+{
+    const char *b;
+    char *n;
+    int ret;
+
+    if (!logName) {
+        return -1; /* NB: log_id_t is unsigned */
+    }
+    b = strrchr(logName, '/');
+    if (!b) {
+        b = logName;
+    } else {
+        ++b;
+    }
+
+    ret = check_allocate_accessible(&n, b, O_RDONLY);
+    free(n);
+    if (ret) {
+        return ret;
+    }
+
+    for(ret = LOG_ID_MIN; ret < LOG_ID_MAX; ++ret) {
+        const char *l = LOG_NAME[ret];
+        if (l && !strcmp(b, l)) {
+            return ret;
+        }
+    }
+    return -1;   /* should never happen */
+}
+
+struct logger_list {
+    struct listnode node;
+    int mode;
+    unsigned int tail;
+    pid_t pid;
+    unsigned int queued_lines;
+    int timeout_ms;
+    int error;
+    bool flush;
+    bool valid_entry; /* valiant(?) effort to deal with memory starvation */
+    struct log_msg entry;
+};
+
+struct log_list {
+    struct listnode node;
+    struct log_msg entry; /* Truncated to event->len() + 1 to save space */
+};
+
+struct logger {
+    struct listnode node;
+    struct logger_list *top;
+    int fd;
+    log_id_t id;
+    short *revents;
+    struct listnode log_list;
+};
+
+/* android_logger_alloc unimplemented, no use case */
+/* android_logger_free not exported */
+static void android_logger_free(struct logger *logger)
+{
+    if (!logger) {
+        return;
+    }
+
+    while (!list_empty(&logger->log_list)) {
+        struct log_list *entry = node_to_item(
+            list_head(&logger->log_list), struct log_list, node);
+        list_remove(&entry->node);
+        free(entry);
+        if (logger->top->queued_lines) {
+            logger->top->queued_lines--;
+        }
+    }
+
+    if (logger->fd >= 0) {
+        close(logger->fd);
+    }
+
+    list_remove(&logger->node);
+
+    free(logger);
+}
+
+log_id_t android_logger_get_id(struct logger *logger)
+{
+    return logger->id;
+}
+
+/* worker for sending the command to the logger */
+static int logger_ioctl(struct logger *logger, int cmd, int mode)
+{
+    char *n;
+    int  f, ret;
+
+    if (!logger || !logger->top) {
+        return -EFAULT;
+    }
+
+    if (((mode & O_ACCMODE) == O_RDWR)
+            || (((mode ^ logger->top->mode) & O_ACCMODE) == 0)) {
+        return ioctl(logger->fd, cmd);
+    }
+
+    /* We go here if android_logger_list_open got mode wrong for this ioctl */
+    ret = check_allocate_accessible(&n, android_log_id_to_name(logger->id), mode);
+    if (ret) {
+        free(n);
+        return ret;
+    }
+
+    f = open(n, mode);
+    free(n);
+    if (f < 0) {
+        return f;
+    }
+
+    ret = ioctl(f, cmd);
+    close (f);
+
+    return ret;
+}
+
+int android_logger_clear(struct logger *logger)
+{
+    return logger_ioctl(logger, LOGGER_FLUSH_LOG, O_WRONLY);
+}
+
+/* returns the total size of the log's ring buffer */
+int android_logger_get_log_size(struct logger *logger)
+{
+    return logger_ioctl(logger, LOGGER_GET_LOG_BUF_SIZE, O_RDWR);
+}
+
+/*
+ * returns the readable size of the log's ring buffer (that is, amount of the
+ * log consumed)
+ */
+int android_logger_get_log_readable_size(struct logger *logger)
+{
+    return logger_ioctl(logger, LOGGER_GET_LOG_LEN, O_RDONLY);
+}
+
+/*
+ * returns the logger version
+ */
+int android_logger_get_log_version(struct logger *logger)
+{
+    int ret = logger_ioctl(logger, LOGGER_GET_VERSION, O_RDWR);
+    return (ret < 0) ? 1 : ret;
+}
+
+struct logger_list *android_logger_list_alloc(int mode,
+                                              unsigned int tail,
+                                              pid_t pid)
+{
+    struct logger_list *logger_list;
+
+    logger_list = calloc(1, sizeof(*logger_list));
+    if (!logger_list) {
+        return NULL;
+    }
+    list_init(&logger_list->node);
+    logger_list->mode = mode;
+    logger_list->tail = tail;
+    logger_list->pid = pid;
+    return logger_list;
+}
+
+/* android_logger_list_register unimplemented, no use case */
+/* android_logger_list_unregister unimplemented, no use case */
+
+/* Open the named log and add it to the logger list */
+struct logger *android_logger_open(struct logger_list *logger_list,
+                                   log_id_t id)
+{
+    struct listnode *node;
+    struct logger *logger;
+    char *n;
+
+    if (!logger_list || (id >= LOG_ID_MAX)) {
+        goto err;
+    }
+
+    logger_for_each(logger, logger_list) {
+        if (logger->id == id) {
+            goto ok;
+        }
+    }
+
+    logger = calloc(1, sizeof(*logger));
+    if (!logger) {
+        goto err;
+    }
+
+    if (check_allocate_accessible(&n, android_log_id_to_name(id),
+                                  logger_list->mode)) {
+        goto err_name;
+    }
+
+    logger->fd = open(n, logger_list->mode);
+    if (logger->fd < 0) {
+        goto err_name;
+    }
+
+    free(n);
+    logger->id = id;
+    list_init(&logger->log_list);
+    list_add_tail(&logger_list->node, &logger->node);
+    logger->top = logger_list;
+    logger_list->timeout_ms = LOG_TIMEOUT_FLUSH;
+    goto ok;
+
+err_name:
+    free(n);
+err_logger:
+    free(logger);
+err:
+    logger = NULL;
+ok:
+    return logger;
+}
+
+/* Open the single named log and make it part of a new logger list */
+struct logger_list *android_logger_list_open(log_id_t id,
+                                             int mode,
+                                             unsigned int tail,
+                                             pid_t pid)
+{
+    struct logger_list *logger_list = android_logger_list_alloc(mode, tail, pid);
+    if (!logger_list) {
+        return NULL;
+    }
+
+    if (!android_logger_open(logger_list, id)) {
+        android_logger_list_free(logger_list);
+        return NULL;
+    }
+
+    return logger_list;
+}
+
+/* prevent memory starvation when backfilling */
+static unsigned int queue_threshold(struct logger_list *logger_list)
+{
+    return (logger_list->tail < 64) ? 64 : logger_list->tail;
+}
+
+static bool low_queue(struct listnode *node)
+{
+    /* low is considered less than 2 */
+    return list_head(node) == list_tail(node);
+}
+
+/* Flush queues in sequential order, one at a time */
+static int android_logger_list_flush(struct logger_list *logger_list,
+                                     struct log_msg *log_msg)
+{
+    int ret = 0;
+    struct log_list *firstentry = NULL;
+
+    while ((ret == 0)
+            && (logger_list->flush
+                || (logger_list->queued_lines > logger_list->tail))) {
+        struct logger *logger;
+
+        /* Merge sort */
+        bool at_least_one_is_low = false;
+        struct logger *firstlogger = NULL;
+        firstentry = NULL;
+
+        logger_for_each(logger, logger_list) {
+            struct listnode *node;
+            struct log_list *oldest = NULL;
+
+            /* kernel logger channels not necessarily time-sort order */
+            list_for_each(node, &logger->log_list) {
+                struct log_list *entry = node_to_item(node,
+                                                      struct log_list, node);
+                if (!oldest
+                        || (entry->entry.entry.sec < oldest->entry.entry.sec)
+                        || ((entry->entry.entry.sec == oldest->entry.entry.sec)
+                            && (entry->entry.entry.nsec < oldest->entry.entry.nsec))) {
+                    oldest = entry;
+                }
+            }
+
+            if (!oldest) {
+                at_least_one_is_low = true;
+                continue;
+            } else if (low_queue(&logger->log_list)) {
+                at_least_one_is_low = true;
+            }
+
+            if (!firstentry
+                    || (oldest->entry.entry.sec < firstentry->entry.entry.sec)
+                    || ((oldest->entry.entry.sec == firstentry->entry.entry.sec)
+                        && (oldest->entry.entry.nsec < firstentry->entry.entry.nsec))) {
+                firstentry = oldest;
+                firstlogger = logger;
+            }
+        }
+
+        if (!firstentry) {
+            break;
+        }
+
+        /* when trimming list, tries to keep one entry behind in each bucket */
+        if (!logger_list->flush
+                && at_least_one_is_low
+                && (logger_list->queued_lines < queue_threshold(logger_list))) {
+            break;
+        }
+
+        /* within tail?, send! */
+        if ((logger_list->tail == 0)
+                || (logger_list->queued_lines <= logger_list->tail)) {
+            int diff;
+            ret = firstentry->entry.entry.hdr_size;
+            if (!ret) {
+                ret = sizeof(firstentry->entry.entry_v1);
+            }
+
+            /* Promote entry to v3 format */
+            memcpy(log_msg->buf, firstentry->entry.buf, ret);
+            diff = sizeof(firstentry->entry.entry_v3) - ret;
+            if (diff < 0) {
+                diff = 0;
+            } else if (diff > 0) {
+                memset(log_msg->buf + ret, 0, diff);
+            }
+            memcpy(log_msg->buf + ret + diff, firstentry->entry.buf + ret,
+                   firstentry->entry.entry.len + 1);
+            ret += diff;
+            log_msg->entry.hdr_size = ret;
+            log_msg->entry.lid = firstlogger->id;
+
+            ret += firstentry->entry.entry.len;
+        }
+
+        /* next entry */
+        list_remove(&firstentry->node);
+        free(firstentry);
+        if (logger_list->queued_lines) {
+            logger_list->queued_lines--;
+        }
+    }
+
+    /* Flushed the list, no longer in tail mode for continuing content */
+    if (logger_list->flush && !firstentry) {
+        logger_list->tail = 0;
+    }
+    return ret;
+}
+
+/* Read from the selected logs */
+int android_logger_list_read(struct logger_list *logger_list,
+                             struct log_msg *log_msg)
+{
+    struct logger *logger;
+    nfds_t nfds;
+    struct pollfd *p, *pollfds = NULL;
+    int error = 0, ret = 0;
+
+    memset(log_msg, 0, sizeof(struct log_msg));
+
+    if (!logger_list) {
+        return -ENODEV;
+    }
+
+    if (!(accessmode(logger_list->mode) & R_OK)) {
+        logger_list->error = EPERM;
+        goto done;
+    }
+
+    nfds = 0;
+    logger_for_each(logger, logger_list) {
+        ++nfds;
+    }
+    if (nfds <= 0) {
+        error = ENODEV;
+        goto done;
+    }
+
+    /* Do we have anything to offer from the buffer or state? */
+    if (logger_list->valid_entry) { /* implies we are also in a flush state */
+        goto flush;
+    }
+
+    ret = android_logger_list_flush(logger_list, log_msg);
+    if (ret) {
+        goto done;
+    }
+
+    if (logger_list->error) { /* implies we are also in a flush state */
+        goto done;
+    }
+
+    /* Lets start grinding on metal */
+    pollfds = calloc(nfds, sizeof(struct pollfd));
+    if (!pollfds) {
+        error = ENOMEM;
+        goto flush;
+    }
+
+    p = pollfds;
+    logger_for_each(logger, logger_list) {
+        p->fd = logger->fd;
+        p->events = POLLIN;
+        logger->revents = &p->revents;
+        ++p;
+    }
+
+    while (!ret && !error) {
+        int result;
+
+        /* If we oversleep it's ok, i.e. ignore EINTR. */
+        result = TEMP_FAILURE_RETRY(
+                    poll(pollfds, nfds, logger_list->timeout_ms));
+
+        if (result <= 0) {
+            if (result) {
+                error = errno;
+            } else if (logger_list->mode & O_NDELAY) {
+                error = EAGAIN;
+            } else {
+                logger_list->timeout_ms = LOG_TIMEOUT_NEVER;
+            }
+
+            logger_list->flush = true;
+            goto try_flush;
+        }
+
+        logger_list->timeout_ms = LOG_TIMEOUT_FLUSH;
+
+        /* Anti starvation */
+        if (!logger_list->flush
+                && (logger_list->queued_lines > (queue_threshold(logger_list) / 2))) {
+            /* Any queues with input pending that is low? */
+            bool starving = false;
+            logger_for_each(logger, logger_list) {
+                if ((*(logger->revents) & POLLIN)
+                        && low_queue(&logger->log_list)) {
+                    starving = true;
+                    break;
+                }
+            }
+
+            /* pushback on any queues that are not low */
+            if (starving) {
+                logger_for_each(logger, logger_list) {
+                    if ((*(logger->revents) & POLLIN)
+                            && !low_queue(&logger->log_list)) {
+                        *(logger->revents) &= ~POLLIN;
+                    }
+                }
+            }
+        }
+
+        logger_for_each(logger, logger_list) {
+            unsigned int hdr_size;
+            struct log_list *entry;
+            int diff;
+
+            if (!(*(logger->revents) & POLLIN)) {
+                continue;
+            }
+
+            memset(logger_list->entry.buf, 0, sizeof(struct log_msg));
+            /* NOTE: driver guarantees we read exactly one full entry */
+            result = read(logger->fd, logger_list->entry.buf,
+                          LOGGER_ENTRY_MAX_LEN);
+            if (result <= 0) {
+                if (!result) {
+                    error = EIO;
+                } else if (errno != EINTR) {
+                    error = errno;
+                }
+                continue;
+            }
+
+            if (logger_list->pid
+                    && (logger_list->pid != logger_list->entry.entry.pid)) {
+                continue;
+            }
+
+            hdr_size = logger_list->entry.entry.hdr_size;
+            if (!hdr_size) {
+                hdr_size = sizeof(logger_list->entry.entry_v1);
+            }
+
+            if ((hdr_size > sizeof(struct log_msg))
+                    || (logger_list->entry.entry.len
+                        > sizeof(logger_list->entry.buf) - hdr_size)
+                    || (logger_list->entry.entry.len != result - hdr_size)) {
+                error = EINVAL;
+                continue;
+            }
+
+            /* Promote entry to v3 format */
+            diff = sizeof(logger_list->entry.entry_v3) - hdr_size;
+            if (diff > 0) {
+                if (logger_list->entry.entry.len
+                        > sizeof(logger_list->entry.buf) - hdr_size - diff) {
+                    error = EINVAL;
+                    continue;
+                }
+                result += diff;
+                memmove(logger_list->entry.buf + hdr_size + diff,
+                        logger_list->entry.buf + hdr_size,
+                        logger_list->entry.entry.len + 1);
+                memset(logger_list->entry.buf + hdr_size, 0, diff);
+                logger_list->entry.entry.hdr_size = hdr_size + diff;
+            }
+            logger_list->entry.entry.lid = logger->id;
+
+            /* speedup: If not tail, and only one list, send directly */
+            if (!logger_list->tail
+                    && (list_head(&logger_list->node)
+                        == list_tail(&logger_list->node))) {
+                ret = result;
+                memcpy(log_msg->buf, logger_list->entry.buf, result + 1);
+                break;
+            }
+
+            entry = malloc(sizeof(*entry) - sizeof(entry->entry) + result + 1);
+
+            if (!entry) {
+                logger_list->valid_entry = true;
+                error = ENOMEM;
+                break;
+            }
+
+            logger_list->queued_lines++;
+
+            memcpy(entry->entry.buf, logger_list->entry.buf, result);
+            entry->entry.buf[result] = '\0';
+            list_add_tail(&logger->log_list, &entry->node);
+        }
+
+        if (ret <= 0) {
+try_flush:
+            ret = android_logger_list_flush(logger_list, log_msg);
+        }
+    }
+
+    free(pollfds);
+
+flush:
+    if (error) {
+        logger_list->flush = true;
+    }
+
+    if (ret <= 0) {
+        ret = android_logger_list_flush(logger_list, log_msg);
+
+        if (!ret && logger_list->valid_entry) {
+            ret = logger_list->entry.entry.hdr_size;
+            if (!ret) {
+                ret = sizeof(logger_list->entry.entry_v1);
+            }
+            ret += logger_list->entry.entry.len;
+
+            memcpy(log_msg->buf, logger_list->entry.buf,
+                   sizeof(struct log_msg));
+            logger_list->valid_entry = false;
+        }
+    }
+
+done:
+    if (logger_list->error) {
+        error = logger_list->error;
+    }
+    if (error) {
+        logger_list->error = error;
+        if (!ret) {
+            ret = -error;
+        }
+    }
+    return ret;
+}
+
+/* Close all the logs */
+void android_logger_list_free(struct logger_list *logger_list)
+{
+    if (logger_list == NULL) {
+        return;
+    }
+
+    while (!list_empty(&logger_list->node)) {
+        struct listnode *node = list_head(&logger_list->node);
+        struct logger *logger = node_to_item(node, struct logger, node);
+        android_logger_free(logger);
+    }
+
+    free(logger_list);
+}