path: root/liblog/logd_write_kern.c

/*
 * Copyright (C) 2007-2014 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.
 */

#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#ifdef __BIONIC__
#include <android/set_abort_message.h>
#endif

#include <log/log.h>
#include <log/logd.h>
#include <log/logger.h>

#define LOGGER_LOG_MAIN		"log/main"
#define LOGGER_LOG_RADIO	"log/radio"
#define LOGGER_LOG_EVENTS	"log/events"
#define LOGGER_LOG_SYSTEM	"log/system"

#define LOG_BUF_SIZE 1024

#define log_open(pathname, flags) open(pathname, (flags) | O_CLOEXEC)
#define log_writev(filedes, vector, count) writev(filedes, vector, count)
#define log_close(filedes) close(filedes)

static int __write_to_log_init(log_id_t, struct iovec *vec, size_t nr);
static int (*write_to_log)(log_id_t, struct iovec *vec, size_t nr) = __write_to_log_init;

static pthread_mutex_t log_init_lock = PTHREAD_MUTEX_INITIALIZER;

#ifndef __unused
#define __unused  __attribute__((__unused__))
#endif

static int log_fds[(int)LOG_ID_MAX] = { -1, -1, -1, -1 };

/*
 * This is used by the C++ code to decide if it should write logs through
 * the C code.  Basically, if /dev/log/... is available, we're running in
 * the simulator rather than a desktop tool and want to use the device.
 */
static enum {
    kLogUninitialized, kLogNotAvailable, kLogAvailable
} g_log_status = kLogUninitialized;
int __android_log_dev_available(void)
{
    if (g_log_status == kLogUninitialized) {
        if (access("/dev/"LOGGER_LOG_MAIN, W_OK) == 0)
            g_log_status = kLogAvailable;
        else
            g_log_status = kLogNotAvailable;
    }

    return (g_log_status == kLogAvailable);
}

static int __write_to_log_null(log_id_t log_fd __unused, struct iovec *vec __unused,
                               size_t nr __unused)
{
    return -1;
}

static int __write_to_log_kernel(log_id_t log_id, struct iovec *vec, size_t nr)
{
    ssize_t ret;
    int log_fd;

    if (/*(int)log_id >= 0 &&*/ (int)log_id < (int)LOG_ID_MAX) {
        if (log_id == LOG_ID_CRASH) {
            log_id = LOG_ID_MAIN;
        }
        log_fd = log_fds[(int)log_id];
    } else {
        return -EBADF;
    }

    do {
        ret = log_writev(log_fd, vec, nr);
        if (ret < 0) {
            ret = -errno;
        }
    } while (ret == -EINTR);

    return ret;
}

/*
 * Release any logger resources. A new log write will immediately re-acquire.
 */
void __android_log_close()
{
#ifdef HAVE_PTHREADS
    pthread_mutex_lock(&log_init_lock);
#endif

    write_to_log = __write_to_log_init;

    /*
     * Threads that are actively writing at this point are not held back
     * by a lock and are at risk of dropping the messages with a return code
     * -EBADF. Prefer to return error code than add the overhead of a lock to
     * each log writing call to guarantee delivery. In addition, anyone
     * calling this is doing so to release the logging resources and shut down,
     * for them to do so with outstanding log requests in other threads is a
     * disengenuous use of this function.
     */

    log_close(log_fds[LOG_ID_MAIN]);
    log_fds[LOG_ID_MAIN] = -1;
    log_close(log_fds[LOG_ID_RADIO]);
    log_fds[LOG_ID_RADIO] = -1;
    log_close(log_fds[LOG_ID_EVENTS]);
    log_fds[LOG_ID_EVENTS] = -1;
    log_close(log_fds[LOG_ID_SYSTEM]);
    log_fds[LOG_ID_SYSTEM] = -1;

#ifdef HAVE_PTHREADS
    pthread_mutex_unlock(&log_init_lock);
#endif
}

static int __write_to_log_init(log_id_t log_id, struct iovec *vec, size_t nr)
{
    pthread_mutex_lock(&log_init_lock);

    if (write_to_log == __write_to_log_init) {
        log_fds[LOG_ID_MAIN] = log_open("/dev/"LOGGER_LOG_MAIN, O_WRONLY);
        log_fds[LOG_ID_RADIO] = log_open("/dev/"LOGGER_LOG_RADIO, O_WRONLY);
        log_fds[LOG_ID_EVENTS] = log_open("/dev/"LOGGER_LOG_EVENTS, O_WRONLY);
        log_fds[LOG_ID_SYSTEM] = log_open("/dev/"LOGGER_LOG_SYSTEM, O_WRONLY);

        write_to_log = __write_to_log_kernel;

        if (log_fds[LOG_ID_MAIN] < 0 || log_fds[LOG_ID_RADIO] < 0 ||
                log_fds[LOG_ID_EVENTS] < 0) {
            log_close(log_fds[LOG_ID_MAIN]);
            log_close(log_fds[LOG_ID_RADIO]);
            log_close(log_fds[LOG_ID_EVENTS]);
            log_fds[LOG_ID_MAIN] = -1;
            log_fds[LOG_ID_RADIO] = -1;
            log_fds[LOG_ID_EVENTS] = -1;
            write_to_log = __write_to_log_null;
        }

        if (log_fds[LOG_ID_SYSTEM] < 0) {
            log_fds[LOG_ID_SYSTEM] = log_fds[LOG_ID_MAIN];
        }
    }

    pthread_mutex_unlock(&log_init_lock);

    return write_to_log(log_id, vec, nr);
}

int __android_log_write(int prio, const char *tag, const char *msg)
{
    return __android_log_buf_write(LOG_ID_MAIN, prio, tag, msg);
}

int __android_log_buf_write(int bufID, int prio, const char *tag, const char *msg)
{
    struct iovec vec[3];
    char tmp_tag[32];

    if (!tag)
        tag = "";

    /* XXX: This needs to go! */
    if ((bufID != LOG_ID_RADIO) &&
         (!strcmp(tag, "HTC_RIL") ||
        !strncmp(tag, "RIL", 3) || /* Any log tag with "RIL" as the prefix */
        !strncmp(tag, "IMS", 3) || /* Any log tag with "IMS" as the prefix */
        !strcmp(tag, "AT") ||
        !strcmp(tag, "GSM") ||
        !strcmp(tag, "STK") ||
        !strcmp(tag, "CDMA") ||
        !strcmp(tag, "PHONE") ||
        !strcmp(tag, "SMS"))) {
            bufID = LOG_ID_RADIO;
            /* Inform third party apps/ril/radio.. to use Rlog or RLOG */
            snprintf(tmp_tag, sizeof(tmp_tag), "use-Rlog/RLOG-%s", tag);
            tag = tmp_tag;
    }

#ifdef __BIONIC__
    if (prio == ANDROID_LOG_FATAL) {
        android_set_abort_message(msg);
    }
#endif

    vec[0].iov_base   = (unsigned char *) &prio;
    vec[0].iov_len    = 1;
    vec[1].iov_base   = (void *) tag;
    vec[1].iov_len    = strlen(tag) + 1;
    vec[2].iov_base   = (void *) msg;
    vec[2].iov_len    = strlen(msg) + 1;

    return write_to_log(bufID, vec, 3);
}

int __android_log_vprint(int prio, const char *tag, const char *fmt, va_list ap)
{
    char buf[LOG_BUF_SIZE];

    vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);

    return __android_log_write(prio, tag, buf);
}

int __android_log_print(int prio, const char *tag, const char *fmt, ...)
{
    va_list ap;
    char buf[LOG_BUF_SIZE];

    va_start(ap, fmt);
    vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
    va_end(ap);

    return __android_log_write(prio, tag, buf);
}

int __android_log_buf_print(int bufID, int prio, const char *tag, const char *fmt, ...)
{
    va_list ap;
    char buf[LOG_BUF_SIZE];

    va_start(ap, fmt);
    vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
    va_end(ap);

    return __android_log_buf_write(bufID, prio, tag, buf);
}

void __android_log_assert(const char *cond, const char *tag,
                          const char *fmt, ...)
{
    char buf[LOG_BUF_SIZE];

    if (fmt) {
        va_list ap;
        va_start(ap, fmt);
        vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
        va_end(ap);
    } else {
        /* Msg not provided, log condition.  N.B. Do not use cond directly as
         * format string as it could contain spurious '%' syntax (e.g.
         * "%d" in "blocks%devs == 0").
         */
        if (cond)
            snprintf(buf, LOG_BUF_SIZE, "Assertion failed: %s", cond);
        else
            strcpy(buf, "Unspecified assertion failed");
    }

    __android_log_write(ANDROID_LOG_FATAL, tag, buf);
    abort(); /* abort so we have a chance to debug the situation */
    /* NOTREACHED */
}

int __android_log_bwrite(int32_t tag, const void *payload, size_t len)
{
    struct iovec vec[2];

    vec[0].iov_base = &tag;
    vec[0].iov_len = sizeof(tag);
    vec[1].iov_base = (void*)payload;
    vec[1].iov_len = len;

    return write_to_log(LOG_ID_EVENTS, vec, 2);
}

/*
 * Like __android_log_bwrite, but takes the type as well.  Doesn't work
 * for the general case where we're generating lists of stuff, but very
 * handy if we just want to dump an integer into the log.
 */
int __android_log_btwrite(int32_t tag, char type, const void *payload,
                          size_t len)
{
    struct iovec vec[3];

    vec[0].iov_base = &tag;
    vec[0].iov_len = sizeof(tag);
    vec[1].iov_base = &type;
    vec[1].iov_len = sizeof(type);
    vec[2].iov_base = (void*)payload;
    vec[2].iov_len = len;

    return write_to_log(LOG_ID_EVENTS, vec, 3);
}

/*
 * Like __android_log_bwrite, but used for writing strings to the
 * event log.
 */
int __android_log_bswrite(int32_t tag, const char *payload)
{
    struct iovec vec[4];
    char type = EVENT_TYPE_STRING;
    uint32_t len = strlen(payload);

    vec[0].iov_base = &tag;
    vec[0].iov_len = sizeof(tag);
    vec[1].iov_base = &type;
    vec[1].iov_len = sizeof(type);
    vec[2].iov_base = &len;
    vec[2].iov_len = sizeof(len);
    vec[3].iov_base = (void*)payload;
    vec[3].iov_len = len;

    return write_to_log(LOG_ID_EVENTS, vec, 4);
}