qemu

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/*
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 * SCLP event types
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 *    Operations Command - Line Mode input
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 *    Message            - Line Mode output
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 *
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 * Copyright IBM, Corp. 2013
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 *
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 * Authors:
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 *  Heinz Graalfs <graalfs@linux.vnet.ibm.com>
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2 or (at your
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 * option) any later version.  See the COPYING file in the top-level directory.
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 *
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 */
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#include "qemu/osdep.h"
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#include "qemu/thread.h"
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#include "qemu/error-report.h"
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#include "qemu/module.h"
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#include "chardev/char-fe.h"
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#include "hw/s390x/sclp.h"
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#include "migration/vmstate.h"
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#include "hw/s390x/event-facility.h"
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#include "hw/qdev-properties.h"
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#include "hw/qdev-properties-system.h"
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#include "hw/s390x/ebcdic.h"
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#include "qom/object.h"
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#define SIZE_BUFFER 4096
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#define NEWLINE     "\n"
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typedef struct OprtnsCommand {
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    EventBufferHeader header;
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    MDMSU message_unit;
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    char data[];
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} QEMU_PACKED OprtnsCommand;
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/* max size for line-mode data in 4K SCCB page */
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#define SIZE_CONSOLE_BUFFER (SCCB_DATA_LEN - sizeof(OprtnsCommand))
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struct SCLPConsoleLM {
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    SCLPEvent event;
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    CharBackend chr;
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    bool echo;                  /* immediate echo of input if true        */
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    uint32_t write_errors;      /* errors writing to char layer           */
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    uint32_t length;            /* length of byte stream in buffer        */
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    uint8_t buf[SIZE_CONSOLE_BUFFER];
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};
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typedef struct SCLPConsoleLM SCLPConsoleLM;
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#define TYPE_SCLPLM_CONSOLE "sclplmconsole"
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DECLARE_INSTANCE_CHECKER(SCLPConsoleLM, SCLPLM_CONSOLE,
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                         TYPE_SCLPLM_CONSOLE)
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/*
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*  Character layer call-back functions
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 *
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 * Allow 1 character at a time
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 *
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 * Accumulate bytes from character layer in console buffer,
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 * event_pending is set when a newline character is encountered
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 *
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 * The maximum command line length is limited by the maximum
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 * space available in an SCCB. Line mode console input is sent
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 * truncated to the guest in case it doesn't fit into the SCCB.
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 */
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static int chr_can_read(void *opaque)
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{
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    SCLPConsoleLM *scon = opaque;
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    if (scon->event.event_pending) {
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        return 0;
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    }
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    return 1;
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}
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static void chr_read(void *opaque, const uint8_t *buf, int size)
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{
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    SCLPConsoleLM *scon = opaque;
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    assert(size == 1);
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    if (*buf == '\r' || *buf == '\n') {
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        scon->event.event_pending = true;
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        sclp_service_interrupt(0);
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        return;
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    }
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    if (scon->length == SIZE_CONSOLE_BUFFER) {
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        /* Eat the character, but still process CR and LF.  */
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        return;
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    }
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    scon->buf[scon->length] = *buf;
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    scon->length += 1;
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    if (scon->echo) {
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        /* XXX this blocks entire thread. Rewrite to use
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         * qemu_chr_fe_write and background I/O callbacks */
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        qemu_chr_fe_write_all(&scon->chr, buf, size);
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    }
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}
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/* functions to be called by event facility */
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static bool can_handle_event(uint8_t type)
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{
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    return type == SCLP_EVENT_MESSAGE || type == SCLP_EVENT_PMSGCMD;
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}
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static sccb_mask_t send_mask(void)
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{
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    return SCLP_EVENT_MASK_OP_CMD | SCLP_EVENT_MASK_PMSGCMD;
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}
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static sccb_mask_t receive_mask(void)
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{
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    return SCLP_EVENT_MASK_MSG | SCLP_EVENT_MASK_PMSGCMD;
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}
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/*
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 * Triggered by SCLP's read_event_data
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 * - convert ASCII byte stream to EBCDIC and
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 * - copy converted data into provided (SCLP) buffer
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 */
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static int get_console_data(SCLPEvent *event, uint8_t *buf, size_t *size,
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                            int avail)
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{
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    int len;
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    SCLPConsoleLM *cons = SCLPLM_CONSOLE(event);
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    len = cons->length;
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    /* data need to fit into provided SCLP buffer */
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    if (len > avail) {
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        return 1;
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    }
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    ebcdic_put(buf, (char *)&cons->buf, len);
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    *size = len;
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    cons->length = 0;
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    /* data provided and no more data pending */
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    event->event_pending = false;
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    qemu_notify_event();
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    return 0;
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}
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static int read_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr,
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                           int *slen)
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{
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    int avail, rc;
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    size_t src_len;
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    uint8_t *to;
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    OprtnsCommand *oc = (OprtnsCommand *) evt_buf_hdr;
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    if (!event->event_pending) {
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        /* no data pending */
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        return 0;
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    }
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    to = (uint8_t *)&oc->data;
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    avail = *slen - sizeof(OprtnsCommand);
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    rc = get_console_data(event, to, &src_len, avail);
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    if (rc) {
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        /* data didn't fit, try next SCCB */
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        return 1;
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    }
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    oc->message_unit.mdmsu.gds_id = GDS_ID_MDSMU;
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    oc->message_unit.mdmsu.length = cpu_to_be16(sizeof(struct MDMSU));
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    oc->message_unit.cpmsu.gds_id = GDS_ID_CPMSU;
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    oc->message_unit.cpmsu.length =
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        cpu_to_be16(sizeof(struct MDMSU) - sizeof(GdsVector));
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    oc->message_unit.text_command.gds_id = GDS_ID_TEXTCMD;
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    oc->message_unit.text_command.length =
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        cpu_to_be16(sizeof(struct MDMSU) - (2 * sizeof(GdsVector)));
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    oc->message_unit.self_def_text_message.key = GDS_KEY_SELFDEFTEXTMSG;
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    oc->message_unit.self_def_text_message.length =
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        cpu_to_be16(sizeof(struct MDMSU) - (3 * sizeof(GdsVector)));
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    oc->message_unit.text_message.key = GDS_KEY_TEXTMSG;
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    oc->message_unit.text_message.length =
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        cpu_to_be16(sizeof(GdsSubvector) + src_len);
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    oc->header.length = cpu_to_be16(sizeof(OprtnsCommand) + src_len);
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    oc->header.type = SCLP_EVENT_OPRTNS_COMMAND;
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    *slen = avail - src_len;
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    return 1;
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}
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/*
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 * Triggered by SCLP's write_event_data
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 *  - write console data to character layer
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 *  returns < 0 if an error occurred
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 */
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static int write_console_data(SCLPEvent *event, const uint8_t *buf, int len)
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{
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    SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
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    if (!qemu_chr_fe_backend_connected(&scon->chr)) {
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        /* If there's no backend, we can just say we consumed all data. */
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        return len;
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    }
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    /* XXX this blocks entire thread. Rewrite to use
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     * qemu_chr_fe_write and background I/O callbacks */
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    return qemu_chr_fe_write_all(&scon->chr, buf, len);
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}
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static int process_mdb(SCLPEvent *event, MDBO *mdbo)
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{
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    int rc;
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    int len;
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    uint8_t buffer[SIZE_BUFFER];
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    len = be16_to_cpu(mdbo->length);
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    len -= sizeof(mdbo->length) + sizeof(mdbo->type)
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            + sizeof(mdbo->mto.line_type_flags)
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            + sizeof(mdbo->mto.alarm_control)
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            + sizeof(mdbo->mto._reserved);
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    assert(len <= SIZE_BUFFER);
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    /* convert EBCDIC SCLP contents to ASCII console message */
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    ascii_put(buffer, mdbo->mto.message, len);
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    rc = write_console_data(event, (uint8_t *)NEWLINE, 1);
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    if (rc < 0) {
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        return rc;
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    }
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    return write_console_data(event, buffer, len);
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}
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static int write_event_data(SCLPEvent *event, EventBufferHeader *ebh)
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{
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    int len;
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    int written;
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    int errors = 0;
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    MDBO *mdbo;
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    SclpMsg *data = (SclpMsg *) ebh;
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    SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
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    len = be16_to_cpu(data->mdb.header.length);
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    if (len < sizeof(data->mdb.header)) {
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        return SCLP_RC_INCONSISTENT_LENGTHS;
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    }
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    len -= sizeof(data->mdb.header);
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    /* first check message buffers */
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    mdbo = data->mdb.mdbo;
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    while (len > 0) {
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        if (be16_to_cpu(mdbo->length) > len
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                || be16_to_cpu(mdbo->length) == 0) {
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            return SCLP_RC_INCONSISTENT_LENGTHS;
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        }
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        len -= be16_to_cpu(mdbo->length);
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        mdbo = (void *) mdbo + be16_to_cpu(mdbo->length);
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    }
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    /* then execute */
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    len = be16_to_cpu(data->mdb.header.length) - sizeof(data->mdb.header);
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    mdbo = data->mdb.mdbo;
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    while (len > 0) {
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        switch (be16_to_cpu(mdbo->type)) {
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        case MESSAGE_TEXT:
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            /* message text object */
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            written = process_mdb(event, mdbo);
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            if (written < 0) {
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                /* character layer error */
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                errors++;
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            }
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            break;
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        default: /* ignore */
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            break;
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        }
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        len -= be16_to_cpu(mdbo->length);
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        mdbo = (void *) mdbo + be16_to_cpu(mdbo->length);
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    }
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    if (errors) {
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        scon->write_errors += errors;
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    }
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    data->header.flags = SCLP_EVENT_BUFFER_ACCEPTED;
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    return SCLP_RC_NORMAL_COMPLETION;
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}
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/* functions for live migration */
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static const VMStateDescription vmstate_sclplmconsole = {
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    .name = "sclplmconsole",
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    .version_id = 0,
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    .minimum_version_id = 0,
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    .fields = (const VMStateField[]) {
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        VMSTATE_BOOL(event.event_pending, SCLPConsoleLM),
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        VMSTATE_UINT32(write_errors, SCLPConsoleLM),
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        VMSTATE_UINT32(length, SCLPConsoleLM),
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        VMSTATE_UINT8_ARRAY(buf, SCLPConsoleLM, SIZE_CONSOLE_BUFFER),
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        VMSTATE_END_OF_LIST()
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     }
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};
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/* qemu object creation and initialization functions */
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/* tell character layer our call-back functions */
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static int console_init(SCLPEvent *event)
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{
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    static bool console_available;
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    SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
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    if (console_available) {
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        error_report("Multiple line-mode operator consoles are not supported");
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        return -1;
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    }
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    console_available = true;
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    qemu_chr_fe_set_handlers(&scon->chr, chr_can_read,
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                             chr_read, NULL, NULL, scon, NULL, true);
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    return 0;
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}
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static void console_reset(DeviceState *dev)
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{
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   SCLPEvent *event = SCLP_EVENT(dev);
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   SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
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   event->event_pending = false;
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   scon->length = 0;
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   scon->write_errors = 0;
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}
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static Property console_properties[] = {
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    DEFINE_PROP_CHR("chardev", SCLPConsoleLM, chr),
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    DEFINE_PROP_UINT32("write_errors", SCLPConsoleLM, write_errors, 0),
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    DEFINE_PROP_BOOL("echo", SCLPConsoleLM, echo, true),
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    DEFINE_PROP_END_OF_LIST(),
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};
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static void console_class_init(ObjectClass *klass, void *data)
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{
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    DeviceClass *dc = DEVICE_CLASS(klass);
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    SCLPEventClass *ec = SCLP_EVENT_CLASS(klass);
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    device_class_set_props(dc, console_properties);
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    dc->reset = console_reset;
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    dc->vmsd = &vmstate_sclplmconsole;
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    ec->init = console_init;
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    ec->get_send_mask = send_mask;
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    ec->get_receive_mask = receive_mask;
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    ec->can_handle_event = can_handle_event;
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    ec->read_event_data = read_event_data;
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    ec->write_event_data = write_event_data;
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    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
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}
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static const TypeInfo sclp_console_info = {
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    .name          = TYPE_SCLPLM_CONSOLE,
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    .parent        = TYPE_SCLP_EVENT,
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    .instance_size = sizeof(SCLPConsoleLM),
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    .class_init    = console_class_init,
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    .class_size    = sizeof(SCLPEventClass),
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};
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static void register_types(void)
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{
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    type_register_static(&sclp_console_info);
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}
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type_init(register_types)
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