plugins/trash/trash-plugin.c

	trash-plugin.c revision f8b7943094756bfe85196fc1af2fe453a21f5337
/* Copyright (C) 2005 Timo Sirainen */

#include "lib.h"
#include "array.h"
#include "istream.h"
#include "home-expand.h"
#include "mail-search.h"
#include "quota-private.h"
#include "quota-plugin.h"
#include "trash-plugin.h"

#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>

#define MAX_RETRY_COUNT 3

#define TRASH_CONTEXT(obj) \
    *((void **)array_idx_modifyable(&(obj)->quota_module_contexts, \
                    trash_quota_module_id))

struct trash_quota_root {
    struct quota_backend_vfuncs super;
};

struct trash_mailbox {
    const char *name;
    int priority; /* lower number = higher priority */

    struct mail_storage *storage;

    /* temporarily set while cleaning: */
    struct mailbox *box;
    struct mailbox_transaction_context *trans;
    struct mail_search_context *search_ctx;
    struct mail *mail;

    unsigned int mail_set:1;
};

/* defined by imap, pop3, lda */
extern void (*hook_quota_root_created)(struct quota_root *root);

static void (*trash_next_hook_quota_root_created)(struct quota_root *root);
static unsigned int trash_quota_module_id;

static pool_t config_pool;
/* trash_boxes ordered by priority, highest first */
static array_t ARRAY_DEFINE(trash_boxes, struct trash_mailbox);

static int trash_clean_mailbox_open(struct trash_mailbox *trash)
{
        struct mail_search_arg search_arg;

    trash->box = mailbox_open(trash->storage, trash->name, NULL,
                  MAILBOX_OPEN_KEEP_RECENT);
    trash->trans = mailbox_transaction_begin(trash->box, 0);

    memset(&search_arg, 0, sizeof(search_arg));
    search_arg.type = SEARCH_ALL;

    trash->search_ctx =
        mailbox_search_init(trash->trans, NULL, &search_arg, NULL);
    trash->mail = mail_alloc(trash->trans, MAIL_FETCH_PHYSICAL_SIZE |
                 MAIL_FETCH_RECEIVED_DATE, NULL);

    return mailbox_search_next(trash->search_ctx, trash->mail);
}

static int trash_clean_mailbox_get_next(struct trash_mailbox *trash,
                    time_t *received_time_r)
{
    int ret;

    if (!trash->mail_set) {
        if (trash->box == NULL)
            ret = trash_clean_mailbox_open(trash);
        else
            ret = mailbox_search_next(trash->search_ctx,
                          trash->mail);
        if (ret <= 0)
            return ret;

        trash->mail_set = TRUE;
    }

    *received_time_r = mail_get_received_date(trash->mail);
    return 1;
}

static int trash_try_clean_mails(uint64_t size_needed)
{
    struct trash_mailbox *trashes;
    unsigned int i, j, count, oldest_idx;
    time_t oldest, received;
    uint64_t size;
    int ret = 0;

    trashes = array_get_modifyable(&trash_boxes, &count);
    for (i = 0; i < count; ) {
        /* expunge oldest mails first in all trash boxes with
           same priority */
        oldest_idx = count;
        oldest = (time_t)-1;
        for (j = i; j < count; j++) {
            if (trashes[j].priority != trashes[j].priority)
                break;

            ret = trash_clean_mailbox_get_next(&trashes[i],
                               &received);
            if (ret < 0)
                goto __err;
            if (ret > 0) {
                if (oldest == (time_t)-1 ||
                    received < oldest) {
                    oldest = received;
                    oldest_idx = j;
                }
            }
        }

        if (oldest_idx < count) {
            if (mail_expunge(trashes[oldest_idx].mail) < 0)
                break;

            size = mail_get_physical_size(trashes[oldest_idx].mail);
            if (size >= size_needed) {
                size_needed = 0;
                break;
            }
            trashes[oldest_idx].mail_set = FALSE;

            size_needed -= size;
        } else {
            /* find more mails from next priority's mailbox */
            i = j;
        }
    }

__err:
    for (i = 0; i < count; i++) {
        struct trash_mailbox *trash = &trashes[i];

        mail_free(&trash->mail);
        (void)mailbox_search_deinit(&trash->search_ctx);

        if (size_needed == 0) {
            (void)mailbox_transaction_commit(&trash->trans,
                MAILBOX_SYNC_FLAG_FULL_WRITE);
        } else {
            /* couldn't get enough space, don't expunge anything */
                        mailbox_transaction_rollback(&trash->trans);
        }

        mailbox_close(&trash->box);
    }
    return size_needed == 0;
}

static int
trash_quota_root_try_alloc(struct quota_root_transaction_context *ctx,
               struct mail *mail, bool *too_large_r)
{
    struct trash_quota_root *troot = TRASH_CONTEXT(ctx->root);
    int ret, i;

    for (i = 0; ; i++) {
        ret = troot->super.try_alloc(ctx, mail, too_large_r);
        if (ret != 0 || *too_large_r)
            return ret;

        if (i == MAX_RETRY_COUNT) {
            /* trash_try_clean_mails() should have returned 0 if
               it couldn't get enough space, but allow retrying
               it a couple of times if there was some extra space
               that was needed.. */
            break;
        }

        /* not enough space. try deleting some from mailbox. */
        ret = trash_try_clean_mails(mail_get_physical_size(mail));
        if (ret <= 0)
            return 0;
    }

    return 0;
}

static void trash_quota_root_deinit(struct quota_root *root)
{
    struct trash_quota_root *troot = TRASH_CONTEXT(root);
    void *null = NULL;

    array_idx_set(&root->quota_module_contexts,
              trash_quota_module_id, &null);
    troot->super.deinit(root);
    i_free(troot);
}

static void trash_quota_root_created(struct quota_root *root)
{
    struct trash_quota_root *troot;

    if (trash_next_hook_quota_root_created != NULL)
        trash_next_hook_quota_root_created(root);

    troot = i_new(struct trash_quota_root, 1);
    troot->super = root->v;
    root->v.deinit = trash_quota_root_deinit;
    root->v.try_alloc = trash_quota_root_try_alloc;

    trash_quota_module_id = quota_module_id++;
    array_idx_set(&root->quota_module_contexts,
              trash_quota_module_id, &troot);
}

static int trash_mailbox_priority_cmp(const void *p1, const void *p2)
{
    const struct trash_mailbox *t1 = p1, *t2 = p2;

    return t1->priority - t2->priority;
}

static int read_configuration(const char *path)
{
    struct istream *input;
    const char *line, *name;
    struct trash_mailbox *trash;
    int fd;

    fd = open(path, O_RDONLY);
    if (fd == -1) {
        i_error("open(%s) failed: %m", path);
        return -1;
    }

    p_clear(config_pool);
    ARRAY_CREATE(&trash_boxes, config_pool, struct trash_mailbox, 8);

    input = i_stream_create_file(fd, default_pool, (size_t)-1, FALSE);
    while ((line = i_stream_read_next_line(input)) != NULL) {
        /* <priority> <mailbox name> */
        name = strchr(line, ' ');
        if (name == NULL || name[1] == '\0')
            continue;

        trash = array_append_space(&trash_boxes);
        trash->name = p_strdup(config_pool, name+1);
        trash->priority = atoi(t_strdup_until(line, name));
    }
    i_stream_destroy(&input);
    (void)close(fd);

    qsort(array_get_modifyable(&trash_boxes, NULL),
          array_count(&trash_boxes), sizeof(struct trash_mailbox),
          trash_mailbox_priority_cmp);
    return 0;
}

void trash_plugin_init(void)
{
    const char *env;

    trash_next_hook_quota_root_created = hook_quota_root_created;

    env = getenv("TRASH");
    if (env == NULL)
        return;

    if (quota == NULL) {
        i_error("trash plugin: quota plugin not initialized");
        return;
    }

    config_pool = pool_alloconly_create("trash config", 1024);
    if (read_configuration(env) < 0)
        return;

    hook_quota_root_created = trash_quota_root_created;
}

void trash_plugin_deinit(void)
{
    if (config_pool != NULL)
        pool_unref(config_pool);

    hook_quota_root_created = trash_next_hook_quota_root_created;
}