diff options
Diffstat (limited to 'lib/libarchive/archive_read_open_file.c')
| -rw-r--r-- | lib/libarchive/archive_read_open_file.c | 49 |
1 files changed, 47 insertions, 2 deletions
diff --git a/lib/libarchive/archive_read_open_file.c b/lib/libarchive/archive_read_open_file.c index b0db61c..efdd438 100644 --- a/lib/libarchive/archive_read_open_file.c +++ b/lib/libarchive/archive_read_open_file.c @@ -48,6 +48,7 @@ struct read_file_data { static int file_close(struct archive *, void *); static int file_open(struct archive *, void *); static ssize_t file_read(struct archive *, void *, const void **buff); +static ssize_t file_skip(struct archive *, void *, size_t request); int archive_read_open_file(struct archive *a, const char *filename, @@ -73,7 +74,7 @@ archive_read_open_file(struct archive *a, const char *filename, mine->block_size = block_size; mine->buffer = NULL; mine->fd = -1; - return (archive_read_open(a, mine, file_open, file_read, file_close)); + return (archive_read_open2(a, mine, file_open, file_read, file_skip, file_close)); } static int @@ -119,7 +120,6 @@ file_read(struct archive *a, void *client_data, const void **buff) struct read_file_data *mine = client_data; ssize_t bytes_read; - (void)a; /* UNUSED */ *buff = mine->buffer; bytes_read = read(mine->fd, mine->buffer, mine->block_size); if (bytes_read < 0) { @@ -132,6 +132,51 @@ file_read(struct archive *a, void *client_data, const void **buff) return (bytes_read); } +static ssize_t +file_skip(struct archive *a, void *client_data, size_t request) +{ + struct read_file_data *mine = client_data; + off_t old_offset, new_offset; + + /* Reduce request to the next smallest multiple of block_size */ + request = (request / mine->block_size) * mine->block_size; + /* + * Hurray for lazy evaluation: if the first lseek fails, the second + * one will not be executed. + */ + if (((old_offset = lseek(mine->fd, 0, SEEK_CUR)) < 0) || + ((new_offset = lseek(mine->fd, request, SEEK_CUR)) < 0)) + { + if (errno == ESPIPE) + { + /* + * Failure to lseek() can be caused by the file + * descriptor pointing to a pipe, socket or FIFO. + * Return 0 here, so the compression layer will use + * read()s instead to advance the file descriptor. + * It's slower of course, but works as well. + */ + return (0); + } + /* + * There's been an error other than ESPIPE. This is most + * likely caused by a programmer error (too large request) + * or a corrupted archive file. + */ + if (mine->filename[0] == '\0') + /* + * Should never get here, since lseek() on stdin ought + * to return an ESPIPE error. + */ + archive_set_error(a, errno, "Error seeking in stdin"); + else + archive_set_error(a, errno, "Error seeking in '%s'", + mine->filename); + return (-1); + } + return (new_offset - old_offset); +} + static int file_close(struct archive *a, void *client_data) { |
