fs-metawrap.c revision 41843bdb6cd96d761a18bab5d5825f344d02420c
/* Copyright (c) 2013-2015 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "array.h"
#include "str.h"
#include "strescape.h"
#include "istream.h"
#include "istream-private.h"
#include "istream-concat.h"
#include "istream-metawrap.h"
#include "ostream.h"
#include "ostream-metawrap.h"
#include "iostream-temp.h"
#include "fs-api-private.h"
#define MAX_METADATA_LINE_LEN 8192
struct metawrap_fs {
struct fs fs;
bool wrap_metadata;
};
struct metawrap_fs_file {
struct fs_file file;
struct metawrap_fs *fs;
struct fs_file *super, *super_read;
enum fs_open_mode open_mode;
struct istream *input;
bool metadata_read;
struct ostream *super_output;
struct ostream *temp_output;
string_t *metadata_header;
uoff_t metadata_write_size;
bool metadata_changed_since_write;
};
struct metawrap_fs_iter {
struct fs_iter iter;
struct fs_iter *super;
};
static struct fs *fs_metawrap_alloc(void)
{
struct metawrap_fs *fs;
fs = i_new(struct metawrap_fs, 1);
fs->fs = fs_class_metawrap;
return &fs->fs;
}
static int
fs_metawrap_init(struct fs *_fs, const char *args, const
struct fs_settings *set)
{
struct metawrap_fs *fs = (struct metawrap_fs *)_fs;
const char *parent_name, *parent_args, *error;
if (*args == '\0') {
fs_set_error(_fs, "Parent filesystem not given as parameter");
return -1;
}
parent_args = strchr(args, ':');
if (parent_args == NULL) {
parent_name = args;
parent_args = "";
} else {
parent_name = t_strdup_until(args, parent_args);
parent_args++;
}
if (fs_init(parent_name, parent_args, set, &_fs->parent, &error) < 0) {
fs_set_error(_fs, "%s: %s", parent_name, error);
return -1;
}
if ((fs_get_properties(_fs->parent) & FS_PROPERTY_METADATA) == 0)
fs->wrap_metadata = TRUE;
return 0;
}
static void fs_metawrap_deinit(struct fs *_fs)
{
struct metawrap_fs *fs = (struct metawrap_fs *)_fs;
if (_fs->parent != NULL)
fs_deinit(&_fs->parent);
i_free(fs);
}
static enum fs_properties fs_metawrap_get_properties(struct fs *_fs)
{
const struct metawrap_fs *fs = (const struct metawrap_fs *)_fs;
enum fs_properties props;
props = fs_get_properties(_fs->parent);
if (fs->wrap_metadata) {
/* we don't have a quick stat() to see the file's size,
because of the metadata header */
props &= ~FS_PROPERTY_STAT;
/* Copying can copy the whole metadata. */
props |= FS_PROPERTY_COPY_METADATA;
}
return props;
}
static struct fs_file *
fs_metawrap_file_init(struct fs *_fs, const char *path,
enum fs_open_mode mode, enum fs_open_flags flags)
{
struct metawrap_fs *fs = (struct metawrap_fs *)_fs;
struct metawrap_fs_file *file;
file = i_new(struct metawrap_fs_file, 1);
file->file.fs = _fs;
file->file.path = i_strdup(path);
file->fs = fs;
file->open_mode = mode;
/* avoid unnecessarily creating two seekable streams */
flags &= ~FS_OPEN_FLAG_SEEKABLE;
file->super = fs_file_init(_fs->parent, path, mode | flags);
if (file->fs->wrap_metadata && mode == FS_OPEN_MODE_READONLY &&
(flags & FS_OPEN_FLAG_ASYNC) == 0) {
/* use async stream for super, so fs_read_stream() won't create
another seekable stream unneededly */
file->super_read = fs_file_init(_fs->parent, path, mode | flags |
FS_OPEN_FLAG_ASYNC);
} else {
file->super_read = file->super;
}
fs_metadata_init(&file->file);
return &file->file;
}
static void fs_metawrap_file_deinit(struct fs_file *_file)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
if (file->super_read != file->super && file->super_read != NULL)
fs_file_deinit(&file->super_read);
if (file->metadata_header != NULL)
str_free(&file->metadata_header);
fs_file_deinit(&file->super);
i_free(file->file.path);
i_free(file);
}
static void fs_metawrap_file_close(struct fs_file *_file)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
if (file->input != NULL)
i_stream_unref(&file->input);
if (file->super_read != NULL)
fs_file_close(file->super_read);
if (file->super != NULL)
fs_file_close(file->super);
}
static const char *fs_metawrap_file_get_path(struct fs_file *_file)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
return fs_file_path(file->super);
}
static void
fs_metawrap_set_async_callback(struct fs_file *_file,
fs_file_async_callback_t *callback,
void *context)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
fs_file_set_async_callback(file->super, callback, context);
}
static int fs_metawrap_wait_async(struct fs *_fs)
{
return fs_wait_async(_fs->parent);
}
static void
fs_metawrap_set_metadata(struct fs_file *_file, const char *key,
const char *value)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
if (!file->fs->wrap_metadata)
fs_set_metadata(file->super, key, value);
else {
fs_default_set_metadata(_file, key, value);
file->metadata_changed_since_write = TRUE;
}
}
static int
fs_metawrap_get_metadata(struct fs_file *_file,
const ARRAY_TYPE(fs_metadata) **metadata_r)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
char c;
if (!file->fs->wrap_metadata)
return fs_get_metadata(file->super, metadata_r);
if (!file->metadata_read) {
if (fs_read(_file, &c, 1) < 0)
return -1;
}
*metadata_r = &_file->metadata;
return 0;
}
static bool fs_metawrap_prefetch(struct fs_file *_file, uoff_t length)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
if (!file->fs->wrap_metadata)
return fs_prefetch(file->super, length);
else
return fs_prefetch(file->super_read, length);
}
static ssize_t fs_metawrap_read(struct fs_file *_file, void *buf, size_t size)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
if (!file->fs->wrap_metadata)
return fs_read(file->super, buf, size);
return fs_read_via_stream(_file, buf, size);
}
static void
fs_metawrap_callback(const char *key, const char *value, void *context)
{
struct metawrap_fs_file *file = context;
if (key == NULL) {
file->metadata_read = TRUE;
return;
}
T_BEGIN {
key = str_tabunescape(t_strdup_noconst(key));
value = str_tabunescape(t_strdup_noconst(value));
fs_default_set_metadata(&file->file, key, value);
} T_END;
}
static struct istream *
fs_metawrap_read_stream(struct fs_file *_file, size_t max_buffer_size)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
struct istream *input;
if (!file->fs->wrap_metadata)
return fs_read_stream(file->super, max_buffer_size);
if (file->input != NULL) {
i_stream_ref(file->input);
i_stream_seek(file->input, 0);
return file->input;
}
input = fs_read_stream(file->super_read,
I_MAX(max_buffer_size, MAX_METADATA_LINE_LEN));
file->input = i_stream_create_metawrap(input, fs_metawrap_callback, file);
i_stream_unref(&input);
i_stream_ref(file->input);
return file->input;
}
static int fs_metawrap_write(struct fs_file *_file, const void *data, size_t size)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
if (!file->fs->wrap_metadata)
return fs_write(file->super, data, size);
return fs_write_via_stream(_file, data, size);
}
static void
fs_metawrap_append_metadata(struct metawrap_fs_file *file, string_t *str)
{
const struct fs_metadata *metadata;
array_foreach(&file->file.metadata, metadata) {
if (strncmp(metadata->key, FS_METADATA_INTERNAL_PREFIX,
strlen(FS_METADATA_INTERNAL_PREFIX)) == 0)
continue;
str_append_tabescaped(str, metadata->key);
str_append_c(str, ':');
str_append_tabescaped(str, metadata->value);
str_append_c(str, '\n');
}
str_append_c(str, '\n');
}
static void fs_metawrap_write_metadata(void *context)
{
struct metawrap_fs_file *file = context;
string_t *str = t_str_new(256);
ssize_t ret;
fs_metawrap_append_metadata(file, str);
file->metadata_write_size = str_len(str);
ret = o_stream_send(file->file.output, str_data(str), str_len(str));
if (ret < 0)
o_stream_close(file->file.output);
else
i_assert((size_t)ret == str_len(str));
file->metadata_changed_since_write = FALSE;
}
static void fs_metawrap_write_stream(struct fs_file *_file)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
i_assert(_file->output == NULL);
if (!file->fs->wrap_metadata) {
file->super_output = fs_write_stream(file->super);
_file->output = file->super_output;
} else {
file->temp_output =
iostream_temp_create_named(_file->fs->temp_path_prefix,
IOSTREAM_TEMP_FLAG_TRY_FD_DUP,
fs_file_path(_file));
_file->output = o_stream_create_metawrap(file->temp_output,
fs_metawrap_write_metadata, file);
}
}
static struct istream *
fs_metawrap_create_updated_istream(struct metawrap_fs_file *file,
struct istream *input)
{
struct istream *input2, *inputs[3];
if (file->metadata_header != NULL)
str_truncate(file->metadata_header, 0);
else
file->metadata_header = str_new(default_pool, 1024);
fs_metawrap_append_metadata(file, file->metadata_header);
inputs[0] = i_stream_create_from_data(str_data(file->metadata_header),
str_len(file->metadata_header));
i_stream_seek(input, file->metadata_write_size);
inputs[1] = i_stream_create_limit(input, (uoff_t)-1);
inputs[2] = NULL;
input2 = i_stream_create_concat(inputs);
i_stream_unref(&inputs[0]);
i_stream_unref(&inputs[1]);
return input2;
}
static int fs_metawrap_write_stream_finish(struct fs_file *_file, bool success)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
struct istream *input;
int ret;
if (_file->output != NULL) {
if (_file->output->closed)
success = FALSE;
if (_file->output == file->super_output)
_file->output = NULL;
else
o_stream_unref(&_file->output);
}
if (!success) {
if (file->temp_output != NULL)
o_stream_destroy(&file->temp_output);
if (file->super_output != NULL)
fs_write_stream_abort(file->super, &file->super_output);
return -1;
}
if (file->super_output != NULL) {
/* no metawrap */
i_assert(file->temp_output == NULL);
return fs_write_stream_finish(file->super, &file->super_output);
}
if (file->temp_output == NULL) {
/* finishing up */
i_assert(file->super_output == NULL);
return fs_write_stream_finish(file->super, &file->super_output);
}
/* finish writing the temporary file */
input = iostream_temp_finish(&file->temp_output, IO_BLOCK_SIZE);
if (file->metadata_changed_since_write) {
/* we'll need to recreate the metadata. do this by creating a
new istream combining the new metadata header and the
old body. */
struct istream *input2 = input;
input = fs_metawrap_create_updated_istream(file, input);
i_stream_unref(&input2);
}
file->super_output = fs_write_stream(file->super);
if (o_stream_send_istream(file->super_output, input) >= 0)
ret = fs_write_stream_finish(file->super, &file->super_output);
else if (input->stream_errno != 0) {
fs_set_error(_file->fs, "read(%s) failed: %s",
i_stream_get_name(input),
i_stream_get_error(input));
fs_write_stream_abort(file->super, &file->super_output);
ret = -1;
} else {
i_assert(file->super_output->stream_errno != 0);
fs_set_error(_file->fs, "write(%s) failed: %s",
o_stream_get_name(file->super_output),
o_stream_get_error(file->super_output));
fs_write_stream_abort(file->super, &file->super_output);
ret = -1;
}
i_stream_unref(&input);
return ret;
}
static int
fs_metawrap_lock(struct fs_file *_file, unsigned int secs, struct fs_lock **lock_r)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
return fs_lock(file->super, secs, lock_r);
}
static void fs_metawrap_unlock(struct fs_lock *_lock ATTR_UNUSED)
{
i_unreached();
}
static int fs_metawrap_exists(struct fs_file *_file)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
return fs_exists(file->super);
}
static int fs_metawrap_stat(struct fs_file *_file, struct stat *st_r)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
struct istream *input;
uoff_t input_size;
ssize_t ret;
if (!file->fs->wrap_metadata)
return fs_stat(file->super, st_r);
input = fs_read_stream(_file, IO_BLOCK_SIZE);
if ((ret = i_stream_get_size(input, TRUE, &input_size)) < 0) {
fs_set_error(_file->fs, "i_stream_get_size(%s) failed: %m",
fs_file_path(_file));
i_stream_unref(&input);
return -1;
}
i_stream_unref(&input);
if (ret == 0) {
fs_set_error_async(_file->fs);
return -1;
}
if (fs_stat(file->super, st_r) < 0) {
i_assert(errno != EAGAIN); /* read should have caught this */
return -1;
}
st_r->st_size = input_size;
return 0;
}
static int fs_metawrap_copy(struct fs_file *_src, struct fs_file *_dest)
{
struct metawrap_fs_file *src = (struct metawrap_fs_file *)_src;
struct metawrap_fs_file *dest = (struct metawrap_fs_file *)_dest;
if (!dest->fs->wrap_metadata || !_dest->metadata_changed) {
if (_src != NULL)
return fs_copy(src->super, dest->super);
else
return fs_copy_finish_async(dest->super);
}
return fs_default_copy(_src, _dest);
}
static int fs_metawrap_rename(struct fs_file *_src, struct fs_file *_dest)
{
struct metawrap_fs_file *src = (struct metawrap_fs_file *)_src;
struct metawrap_fs_file *dest = (struct metawrap_fs_file *)_dest;
return fs_rename(src->super, dest->super);
}
static int fs_metawrap_delete(struct fs_file *_file)
{
struct metawrap_fs_file *file = (struct metawrap_fs_file *)_file;
return fs_delete(file->super);
}
static struct fs_iter *
fs_metawrap_iter_init(struct fs *_fs, const char *path,
enum fs_iter_flags flags)
{
struct metawrap_fs_iter *iter;
iter = i_new(struct metawrap_fs_iter, 1);
iter->iter.fs = _fs;
iter->iter.flags = flags;
iter->super = fs_iter_init(_fs->parent, path, flags);
return &iter->iter;
}
static const char *fs_metawrap_iter_next(struct fs_iter *_iter)
{
struct metawrap_fs_iter *iter = (struct metawrap_fs_iter *)_iter;
const char *fname;
iter->super->async_callback = _iter->async_callback;
iter->super->async_context = _iter->async_context;
fname = fs_iter_next(iter->super);
_iter->async_have_more = iter->super->async_have_more;
return fname;
}
static int fs_metawrap_iter_deinit(struct fs_iter *_iter)
{
struct metawrap_fs_iter *iter = (struct metawrap_fs_iter *)_iter;
int ret;
ret = fs_iter_deinit(&iter->super);
i_free(iter);
return ret;
}
const struct fs fs_class_metawrap = {
.name = "metawrap",
.v = {
fs_metawrap_alloc,
fs_metawrap_init,
fs_metawrap_deinit,
fs_metawrap_get_properties,
fs_metawrap_file_init,
fs_metawrap_file_deinit,
fs_metawrap_file_close,
fs_metawrap_file_get_path,
fs_metawrap_set_async_callback,
fs_metawrap_wait_async,
fs_metawrap_set_metadata,
fs_metawrap_get_metadata,
fs_metawrap_prefetch,
fs_metawrap_read,
fs_metawrap_read_stream,
fs_metawrap_write,
fs_metawrap_write_stream,
fs_metawrap_write_stream_finish,
fs_metawrap_lock,
fs_metawrap_unlock,
fs_metawrap_exists,
fs_metawrap_stat,
fs_metawrap_copy,
fs_metawrap_rename,
fs_metawrap_delete,
fs_metawrap_iter_init,
fs_metawrap_iter_next,
fs_metawrap_iter_deinit
}
};