src/log/log-error-buffer.c

/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "log-error-buffer.h"

#define LOG_ERROR_BUFFER_MAX_LINES 1000

struct log_error_data {
    struct log_error_data *next;

    enum log_type type;
    time_t timestamp;
    unsigned char prefix_text[FLEXIBLE_ARRAY_MEMBER];
};

struct log_error_buffer {
    struct log_error_data *head, *tail;
    unsigned int count;
};

struct log_error_buffer_iter {
    struct log_error_buffer *buf;
    struct log_error_data *cur;
    struct log_error error;
};

struct log_error_buffer *log_error_buffer_init(void)
{
    struct log_error_buffer *buf;

    buf = i_new(struct log_error_buffer, 1);
    return buf;
}

static void log_error_buffer_delete_head(struct log_error_buffer *buf)
{
    struct log_error_data *data;

    i_assert(buf->head != NULL);

    buf->count--;
    data = buf->head;
    buf->head = data->next;
    if (buf->tail == data) {
        /* last one */
        buf->tail = NULL;
    }
    i_free(data);
}

void log_error_buffer_add(struct log_error_buffer *buf,
              const struct log_error *error)
{
    size_t prefix_size = strlen(error->prefix)+1;
    size_t text_size = strlen(error->text)+1;
    struct log_error_data *data;

    if (buf->count == LOG_ERROR_BUFFER_MAX_LINES)
        log_error_buffer_delete_head(buf);

    /* @UNSAFE */
    data = i_malloc(MALLOC_ADD(sizeof(*data),
                   MALLOC_ADD(prefix_size, text_size)));
    data->type = error->type;
    data->timestamp = error->timestamp;
    memcpy(data->prefix_text, error->prefix, prefix_size);
    memcpy(data->prefix_text + prefix_size, error->text, text_size);

    if (buf->tail != NULL)
        buf->tail->next = data;
    else
        buf->head = data;
    buf->tail = data;
    buf->count++;
}

void log_error_buffer_deinit(struct log_error_buffer **_buf)
{
    struct log_error_buffer *buf = *_buf;

    *_buf = NULL;
    while (buf->count > 0)
        log_error_buffer_delete_head(buf);
    i_free(buf);
}

struct log_error_buffer_iter *
log_error_buffer_iter_init(struct log_error_buffer *buf)
{
    struct log_error_buffer_iter *iter;

    iter = i_new(struct log_error_buffer_iter, 1);
    iter->buf = buf;
    iter->cur = buf->head;
    return iter;
}

struct log_error *
log_error_buffer_iter_next(struct log_error_buffer_iter *iter)
{
    struct log_error_data *data = iter->cur;

    if (data == NULL)
        return NULL;
    iter->cur = iter->cur->next;

    iter->error.type = data->type;
    iter->error.timestamp = data->timestamp;
    iter->error.prefix = (const void *)data->prefix_text;
    iter->error.text = (const void *)(data->prefix_text +
                      strlen(iter->error.prefix) + 1);
    return &iter->error;
}

void log_error_buffer_iter_deinit(struct log_error_buffer_iter **_iter)
{
    struct log_error_buffer_iter *iter = *_iter;

    *_iter = NULL;

    i_free(iter);
}