istream-failure-at.c revision 25fb397382c6f7d39bfeee85774e7675f02bfb3c
/* Copyright (c) 2015 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "istream-private.h"
#include "istream-failure-at.h"
struct failure_at_istream {
struct istream_private istream;
char *error_string;
uoff_t failure_offset;
};
static void i_stream_failure_at_destroy(struct iostream_private *stream)
{
struct failure_at_istream *fstream =
(struct failure_at_istream *)stream;
i_free(fstream->error_string);
}
static ssize_t
i_stream_failure_at_read(struct istream_private *stream)
{
struct failure_at_istream *fstream = (struct failure_at_istream *)stream;
uoff_t new_offset;
ssize_t ret;
i_stream_seek(stream->parent, stream->parent_start_offset +
stream->istream.v_offset);
ret = i_stream_read_copy_from_parent(&stream->istream);
new_offset = stream->istream.v_offset + (stream->pos - stream->skip);
if (ret >= 0 && new_offset >= fstream->failure_offset) {
if (stream->istream.v_offset >= fstream->failure_offset) {
/* we already passed the wanted failure offset,
return error immediately. */
stream->pos = stream->skip;
stream->istream.stream_errno = errno = EIO;
io_stream_set_error(&stream->iostream, "%s",
fstream->error_string);
ret = -1;
} else {
/* return data up to the wanted failure offset and
on the next read() call return failure */
size_t new_pos = fstream->failure_offset -
stream->istream.v_offset + stream->skip;
i_assert(new_pos >= stream->skip &&
stream->pos >= new_pos);
ret -= stream->pos - new_pos;
stream->pos = new_pos;
}
} else if (ret < 0 && stream->istream.stream_errno == 0 &&
fstream->failure_offset == (uoff_t)-1) {
/* failure at EOF */
stream->istream.stream_errno = errno = EIO;
io_stream_set_error(&stream->iostream, "%s",
fstream->error_string);
}
return ret;
}
struct istream *
i_stream_create_failure_at(struct istream *input, uoff_t failure_offset,
const char *error_string)
{
struct failure_at_istream *fstream;
fstream = i_new(struct failure_at_istream, 1);
fstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
fstream->istream.stream_size_passthrough = TRUE;
fstream->istream.read = i_stream_failure_at_read;
fstream->istream.iostream.destroy = i_stream_failure_at_destroy;
fstream->istream.istream.readable_fd = input->readable_fd;
fstream->istream.istream.blocking = input->blocking;
fstream->istream.istream.seekable = input->seekable;
fstream->error_string = i_strdup(error_string);
fstream->failure_offset = failure_offset;
return i_stream_create(&fstream->istream, input,
i_stream_get_fd(input));
}
struct istream *
i_stream_create_failure_at_eof(struct istream *input, const char *error_string)
{
return i_stream_create_failure_at(input, (uoff_t)-1, error_string);
}