/* -*- linux-c -*- * Print Flush Function * Copyright (C) 2007-2008 Red Hat Inc. * * This file is part of systemtap, and is free software. You can * redistribute it and/or modify it under the terms of the GNU General * Public License (GPL); either version 2, or (at your option) any * later version. */ /** Send the print buffer to the transport now. * Output accumulates in the print buffer until it * is filled, or this is called. This MUST be called before returning * from a probe or accumulated output in the print buffer will be lost. * * @note Interrupts must be disabled to use this. */ static void __stp_print_flush(struct _stp_log *log) { char *bufp = log->buf; /* next byte of log->buf left to write */ size_t len = log->len; /* # bytes of log->buf left to write */ const size_t hlen = sizeof(struct _stp_trace); void *entry = NULL; /* current output buf handle */ size_t bytes_reserved; /* current output buf size available */ /* check to see if there is anything in the buffer */ if (likely(len == 0)) return; if (unlikely(log->no_flush)) { log->is_full = true; return; } log->len = 0; /* clear it for later reuse */ dbug_trans(1, "len = %zu\n", len); /* try to reserve header + len */ bytes_reserved = _stp_data_write_reserve(hlen+len, &entry); /* require at least header to fit in its entirety */ if (likely(entry && bytes_reserved > hlen)) { /* copy new _stp_trace_ header */ struct _stp_trace t = { .magic = STAP_TRACE_MAGIC, .sequence = _stp_seq_inc(), .pdu_len = len }; memcpy(_stp_data_entry_data(entry), &t, hlen); /* copy the first part of the message */ memcpy(_stp_data_entry_data(entry)+hlen, bufp, bytes_reserved-hlen); bufp += bytes_reserved-hlen; len -= bytes_reserved-hlen; /* send header + first part */ _stp_data_write_commit(entry); /* loop to copy the rest of the message into subsequent bufs */ while (len > 0) { bytes_reserved = _stp_data_write_reserve(len, &entry); if (likely(entry && bytes_reserved)) { memcpy(_stp_data_entry_data(entry), bufp, bytes_reserved); _stp_data_write_commit(entry); bufp += bytes_reserved; len -= bytes_reserved; } else { /* rest of message cannot fit at this time */ /* NB: the receiver must somehow resynch the framing! */ atomic_inc(&_stp_transport_failures); break; } } } else { atomic_inc(&_stp_transport_failures); } }