Re: [Qemu-devel] [PATCH v2 01/10] ipmi: remove IPMI_CHECK_CMD_LEN() macro

[Cédric Le Goater]

On 03/05/2016 12:41 PM, Corey Minyard wrote:
> On 03/02/2016 04:14 AM, Cédric Le Goater wrote:
>> Most IPMI command handlers in the BMC simulator start with a call to
>> the macro IPMI_CHECK_CMD_LEN() which verifies that a minimal number of
>> arguments expected by the command are indeed available. To achieve
>> this task, the macro implicitly uses local variables which is
>> misleading in the code.
>>
>> This patch adds a 'cmd_len_min' attribute to the struct IPMICmdHandler
>> defining the minimal number of arguments expected by the command and
>> moves this check in the global command handler ipmi_sim_handle_command().
> 
> This is much better.  One style comment inline...
> 
> Acked-by: Corey Minyard <address@hidden>
> 
>> Signed-off-by: Cédric Le Goater <address@hidden>
>> ---
>>   hw/ipmi/ipmi_bmc_sim.c | 137 
>> ++++++++++++++++++++++---------------------------
>>   1 file changed, 62 insertions(+), 75 deletions(-)
>>
>> diff --git a/hw/ipmi/ipmi_bmc_sim.c b/hw/ipmi/ipmi_bmc_sim.c
>> index 51d234aa1bf2..30b9fb48ea2d 100644
>> --- a/hw/ipmi/ipmi_bmc_sim.c
>> +++ b/hw/ipmi/ipmi_bmc_sim.c
>> @@ -155,10 +155,15 @@ typedef struct IPMISensor {
>>   typedef struct IPMIBmcSim IPMIBmcSim;
>>
>>   #define MAX_NETFNS 64
>> -typedef void (*IPMICmdHandler)(IPMIBmcSim *s,
>> -                               uint8_t *cmd, unsigned int cmd_len,
>> -                               uint8_t *rsp, unsigned int *rsp_len,
>> -                               unsigned int max_rsp_len);
>> +
>> +typedef struct IPMICmdHandler {
>> +    void (*cmd_handler)(IPMIBmcSim *s,
>> +                        uint8_t *cmd, unsigned int cmd_len,
>> +                        uint8_t *rsp, unsigned int *rsp_len,
>> +                        unsigned int max_rsp_len);
>> +    unsigned int cmd_len_min;
>> +} IPMICmdHandler;
>> +
>>   typedef struct IPMINetfn {
>>       unsigned int cmd_nums;
>>       const IPMICmdHandler *cmd_handlers;
>> @@ -269,13 +274,6 @@ struct IPMIBmcSim {
>>           rsp[(*rsp_len)++] = (b);                           \
>>       } while (0)
>>
>> -/* Verify that the received command is a certain length. */
>> -#define IPMI_CHECK_CMD_LEN(l) \
>> -    if (cmd_len < l) {                                     \
>> -        rsp[2] = IPMI_CC_REQUEST_DATA_LENGTH_INVALID;      \
>> -        return; \
>> -    }
>> -
>>   /* Check that the reservation in the command is valid. */
>>   #define IPMI_CHECK_RESERVATION(off, r) \
>>       do {                                                   \
>> @@ -623,14 +621,19 @@ static void ipmi_sim_handle_command(IPMIBmc *b,
>>
>>       /* Odd netfns are not valid, make sure the command is registered */
>>       if ((netfn & 1) || !ibs->netfns[netfn / 2] ||
>> -                        (cmd[1] >= ibs->netfns[netfn / 2]->cmd_nums) ||
>> -                        (!ibs->netfns[netfn / 2]->cmd_handlers[cmd[1]])) {
>> +        (cmd[1] >= ibs->netfns[netfn / 2]->cmd_nums) ||
>> +        (!ibs->netfns[netfn / 2]->cmd_handlers[cmd[1]].cmd_handler)) {
>>           rsp[2] = IPMI_CC_INVALID_CMD;
>>           goto out;
> 
> I'm not sure of the qemu style here, but the above change makes the code hard 
> to read.

Cleary. I was lazy. I will try to clarify what this code does with a helper
or some intermediate variables.

Thanks,

C.

> The qemu style really seems to be to not have big if statements like
> this, so maybe this crasy check should be moved to a separate function?
>
>>       }
>>
>> -    ibs->netfns[netfn / 2]->cmd_handlers[cmd[1]](ibs, cmd, cmd_len, rsp, 
>> rsp_len,
>> -                                                max_rsp_len);
>> +    if (cmd_len < ibs->netfns[netfn / 2]->cmd_handlers[cmd[1]].cmd_len_min) 
>> {
>> +        rsp[2] = IPMI_CC_REQUEST_DATA_LENGTH_INVALID;
>> +        goto out;
>> +    }
>> +
>> +    ibs->netfns[netfn / 2]->cmd_handlers[cmd[1]].cmd_handler(ibs, cmd, 
>> cmd_len,
>> +                                                rsp, rsp_len, max_rsp_len);
>>
>>    out:
>>       k->handle_rsp(s, msg_id, rsp, *rsp_len);
>> @@ -737,7 +740,6 @@ static void chassis_control(IPMIBmcSim *ibs,
>>       IPMIInterface *s = ibs->parent.intf;
>>       IPMIInterfaceClass *k = IPMI_INTERFACE_GET_CLASS(s);
>>
>> -    IPMI_CHECK_CMD_LEN(3);
>>       switch (cmd[2] & 0xf) {
>>       case 0: /* power down */
>>           rsp[2] = k->do_hw_op(s, IPMI_POWEROFF_CHASSIS, 0);
>> @@ -838,7 +840,6 @@ static void set_acpi_power_state(IPMIBmcSim *ibs,
>>                             uint8_t *rsp, unsigned int *rsp_len,
>>                             unsigned int max_rsp_len)
>>   {
>> -    IPMI_CHECK_CMD_LEN(4);
>>       ibs->acpi_power_state[0] = cmd[2];
>>       ibs->acpi_power_state[1] = cmd[3];
>>   }
>> @@ -869,7 +870,6 @@ static void set_bmc_global_enables(IPMIBmcSim *ibs,
>>                                      uint8_t *rsp, unsigned int *rsp_len,
>>                                      unsigned int max_rsp_len)
>>   {
>> -    IPMI_CHECK_CMD_LEN(3);
>>       set_global_enables(ibs, cmd[2]);
>>   }
>>
>> @@ -889,7 +889,6 @@ static void clr_msg_flags(IPMIBmcSim *ibs,
>>       IPMIInterface *s = ibs->parent.intf;
>>       IPMIInterfaceClass *k = IPMI_INTERFACE_GET_CLASS(s);
>>
>> -    IPMI_CHECK_CMD_LEN(3);
>>       ibs->msg_flags &= ~cmd[2];
>>       k->set_atn(s, attn_set(ibs), attn_irq_enabled(ibs));
>>   }
>> @@ -976,15 +975,17 @@ static void send_msg(IPMIBmcSim *ibs,
>>       uint8_t *buf;
>>       uint8_t netfn, rqLun, rsLun, rqSeq;
>>
>> -    IPMI_CHECK_CMD_LEN(3);
>> -
>>       if (cmd[2] != 0) {
>>           /* We only handle channel 0 with no options */
>>           rsp[2] = IPMI_CC_INVALID_DATA_FIELD;
>>           return;
>>       }
>>
>> -    IPMI_CHECK_CMD_LEN(10);
>> +    if (cmd_len < 10) {
>> +        rsp[2] = IPMI_CC_REQUEST_DATA_LENGTH_INVALID;
>> +        return;
>> +    }
>> +
>>       if (cmd[3] != 0x40) {
>>           /* We only emulate a MC at address 0x40. */
>>           rsp[2] = 0x83; /* NAK on write */
>> @@ -1092,7 +1093,6 @@ static void set_watchdog_timer(IPMIBmcSim *ibs,
>>       IPMIInterfaceClass *k = IPMI_INTERFACE_GET_CLASS(s);
>>       unsigned int val;
>>
>> -    IPMI_CHECK_CMD_LEN(8);
>>       val = cmd[2] & 0x7; /* Validate use */
>>       if (val == 0 || val > 5) {
>>           rsp[2] = IPMI_CC_INVALID_DATA_FIELD;
>> @@ -1217,7 +1217,6 @@ static void get_sdr(IPMIBmcSim *ibs,
>>       uint16_t nextrec;
>>       struct ipmi_sdr_header *sdrh;
>>
>> -    IPMI_CHECK_CMD_LEN(8);
>>       if (cmd[6]) {
>>           IPMI_CHECK_RESERVATION(2, ibs->sdr.reservation);
>>       }
>> @@ -1271,7 +1270,6 @@ static void clear_sdr_rep(IPMIBmcSim *ibs,
>>                             uint8_t *rsp, unsigned int *rsp_len,
>>                             unsigned int max_rsp_len)
>>   {
>> -    IPMI_CHECK_CMD_LEN(8);
>>       IPMI_CHECK_RESERVATION(2, ibs->sdr.reservation);
>>       if (cmd[4] != 'C' || cmd[5] != 'L' || cmd[6] != 'R') {
>>           rsp[2] = IPMI_CC_INVALID_DATA_FIELD;
>> @@ -1330,7 +1328,6 @@ static void get_sel_entry(IPMIBmcSim *ibs,
>>   {
>>       unsigned int val;
>>
>> -    IPMI_CHECK_CMD_LEN(8);
>>       if (cmd[6]) {
>>           IPMI_CHECK_RESERVATION(2, ibs->sel.reservation);
>>       }
>> @@ -1375,7 +1372,6 @@ static void add_sel_entry(IPMIBmcSim *ibs,
>>                             uint8_t *rsp, unsigned int *rsp_len,
>>                             unsigned int max_rsp_len)
>>   {
>> -    IPMI_CHECK_CMD_LEN(18);
>>       if (sel_add_event(ibs, cmd + 2)) {
>>           rsp[2] = IPMI_CC_OUT_OF_SPACE;
>>           return;
>> @@ -1390,7 +1386,6 @@ static void clear_sel(IPMIBmcSim *ibs,
>>                         uint8_t *rsp, unsigned int *rsp_len,
>>                         unsigned int max_rsp_len)
>>   {
>> -    IPMI_CHECK_CMD_LEN(8);
>>       IPMI_CHECK_RESERVATION(2, ibs->sel.reservation);
>>       if (cmd[4] != 'C' || cmd[5] != 'L' || cmd[6] != 'R') {
>>           rsp[2] = IPMI_CC_INVALID_DATA_FIELD;
>> @@ -1434,7 +1429,6 @@ static void set_sel_time(IPMIBmcSim *ibs,
>>       uint32_t val;
>>       struct ipmi_time now;
>>
>> -    IPMI_CHECK_CMD_LEN(6);
>>       val = cmd[2] | (cmd[3] << 8) | (cmd[4] << 16) | (cmd[5] << 24);
>>       ipmi_gettime(&now);
>>       ibs->sel.time_offset = now.tv_sec - ((long) val);
>> @@ -1447,7 +1441,6 @@ static void set_sensor_evt_enable(IPMIBmcSim *ibs,
>>   {
>>       IPMISensor *sens;
>>
>> -    IPMI_CHECK_CMD_LEN(4);
>>       if ((cmd[2] >= MAX_SENSORS) ||
>>               !IPMI_SENSOR_GET_PRESENT(ibs->sensors + cmd[2])) {
>>           rsp[2] = IPMI_CC_REQ_ENTRY_NOT_PRESENT;
>> @@ -1499,7 +1492,6 @@ static void get_sensor_evt_enable(IPMIBmcSim *ibs,
>>   {
>>       IPMISensor *sens;
>>
>> -    IPMI_CHECK_CMD_LEN(3);
>>       if ((cmd[2] >= MAX_SENSORS) ||
>>           !IPMI_SENSOR_GET_PRESENT(ibs->sensors + cmd[2])) {
>>           rsp[2] = IPMI_CC_REQ_ENTRY_NOT_PRESENT;
>> @@ -1520,7 +1512,6 @@ static void rearm_sensor_evts(IPMIBmcSim *ibs,
>>   {
>>       IPMISensor *sens;
>>
>> -    IPMI_CHECK_CMD_LEN(4);
>>       if ((cmd[2] >= MAX_SENSORS) ||
>>           !IPMI_SENSOR_GET_PRESENT(ibs->sensors + cmd[2])) {
>>           rsp[2] = IPMI_CC_REQ_ENTRY_NOT_PRESENT;
>> @@ -1542,7 +1533,6 @@ static void get_sensor_evt_status(IPMIBmcSim *ibs,
>>   {
>>       IPMISensor *sens;
>>
>> -    IPMI_CHECK_CMD_LEN(3);
>>       if ((cmd[2] >= MAX_SENSORS) ||
>>           !IPMI_SENSOR_GET_PRESENT(ibs->sensors + cmd[2])) {
>>           rsp[2] = IPMI_CC_REQ_ENTRY_NOT_PRESENT;
>> @@ -1564,7 +1554,6 @@ static void get_sensor_reading(IPMIBmcSim *ibs,
>>   {
>>       IPMISensor *sens;
>>
>> -    IPMI_CHECK_CMD_LEN(3);
>>       if ((cmd[2] >= MAX_SENSORS) ||
>>               !IPMI_SENSOR_GET_PRESENT(ibs->sensors + cmd[2])) {
>>           rsp[2] = IPMI_CC_REQ_ENTRY_NOT_PRESENT;
>> @@ -1587,7 +1576,6 @@ static void set_sensor_type(IPMIBmcSim *ibs,
>>       IPMISensor *sens;
>>
>>
>> -    IPMI_CHECK_CMD_LEN(5);
>>       if ((cmd[2] >= MAX_SENSORS) ||
>>               !IPMI_SENSOR_GET_PRESENT(ibs->sensors + cmd[2])) {
>>           rsp[2] = IPMI_CC_REQ_ENTRY_NOT_PRESENT;
>> @@ -1606,7 +1594,6 @@ static void get_sensor_type(IPMIBmcSim *ibs,
>>       IPMISensor *sens;
>>
>>
>> -    IPMI_CHECK_CMD_LEN(3);
>>       if ((cmd[2] >= MAX_SENSORS) ||
>>               !IPMI_SENSOR_GET_PRESENT(ibs->sensors + cmd[2])) {
>>           rsp[2] = IPMI_CC_REQ_ENTRY_NOT_PRESENT;
>> @@ -1619,10 +1606,10 @@ static void get_sensor_type(IPMIBmcSim *ibs,
>>
>>
>>   static const IPMICmdHandler chassis_cmds[] = {
>> -    [IPMI_CMD_GET_CHASSIS_CAPABILITIES] = chassis_capabilities,
>> -    [IPMI_CMD_GET_CHASSIS_STATUS] = chassis_status,
>> -    [IPMI_CMD_CHASSIS_CONTROL] = chassis_control,
>> -    [IPMI_CMD_GET_SYS_RESTART_CAUSE] = chassis_get_sys_restart_cause
>> +    [IPMI_CMD_GET_CHASSIS_CAPABILITIES] = { chassis_capabilities },
>> +    [IPMI_CMD_GET_CHASSIS_STATUS] = { chassis_status },
>> +    [IPMI_CMD_CHASSIS_CONTROL] = { chassis_control, 3 },
>> +    [IPMI_CMD_GET_SYS_RESTART_CAUSE] = { chassis_get_sys_restart_cause }
>>   };
>>   static const IPMINetfn chassis_netfn = {
>>       .cmd_nums = ARRAY_SIZE(chassis_cmds),
>> @@ -1630,13 +1617,13 @@ static const IPMINetfn chassis_netfn = {
>>   };
>>
>>   static const IPMICmdHandler sensor_event_cmds[] = {
>> -    [IPMI_CMD_SET_SENSOR_EVT_ENABLE] = set_sensor_evt_enable,
>> -    [IPMI_CMD_GET_SENSOR_EVT_ENABLE] = get_sensor_evt_enable,
>> -    [IPMI_CMD_REARM_SENSOR_EVTS] = rearm_sensor_evts,
>> -    [IPMI_CMD_GET_SENSOR_EVT_STATUS] = get_sensor_evt_status,
>> -    [IPMI_CMD_GET_SENSOR_READING] = get_sensor_reading,
>> -    [IPMI_CMD_SET_SENSOR_TYPE] = set_sensor_type,
>> -    [IPMI_CMD_GET_SENSOR_TYPE] = get_sensor_type,
>> +    [IPMI_CMD_SET_SENSOR_EVT_ENABLE] = { set_sensor_evt_enable, 4 },
>> +    [IPMI_CMD_GET_SENSOR_EVT_ENABLE] = { get_sensor_evt_enable, 3 },
>> +    [IPMI_CMD_REARM_SENSOR_EVTS] = { rearm_sensor_evts, 4 },
>> +    [IPMI_CMD_GET_SENSOR_EVT_STATUS] = { get_sensor_evt_status, 3 },
>> +    [IPMI_CMD_GET_SENSOR_READING] = { get_sensor_reading, 3 },
>> +    [IPMI_CMD_SET_SENSOR_TYPE] = { set_sensor_type, 5 },
>> +    [IPMI_CMD_GET_SENSOR_TYPE] = { get_sensor_type, 3 },
>>   };
>>   static const IPMINetfn sensor_event_netfn = {
>>       .cmd_nums = ARRAY_SIZE(sensor_event_cmds),
>> @@ -1644,22 +1631,22 @@ static const IPMINetfn sensor_event_netfn = {
>>   };
>>
>>   static const IPMICmdHandler app_cmds[] = {
>> -    [IPMI_CMD_GET_DEVICE_ID] = get_device_id,
>> -    [IPMI_CMD_COLD_RESET] = cold_reset,
>> -    [IPMI_CMD_WARM_RESET] = warm_reset,
>> -    [IPMI_CMD_SET_ACPI_POWER_STATE] = set_acpi_power_state,
>> -    [IPMI_CMD_GET_ACPI_POWER_STATE] = get_acpi_power_state,
>> -    [IPMI_CMD_GET_DEVICE_GUID] = get_device_guid,
>> -    [IPMI_CMD_SET_BMC_GLOBAL_ENABLES] = set_bmc_global_enables,
>> -    [IPMI_CMD_GET_BMC_GLOBAL_ENABLES] = get_bmc_global_enables,
>> -    [IPMI_CMD_CLR_MSG_FLAGS] = clr_msg_flags,
>> -    [IPMI_CMD_GET_MSG_FLAGS] = get_msg_flags,
>> -    [IPMI_CMD_GET_MSG] = get_msg,
>> -    [IPMI_CMD_SEND_MSG] = send_msg,
>> -    [IPMI_CMD_READ_EVT_MSG_BUF] = read_evt_msg_buf,
>> -    [IPMI_CMD_RESET_WATCHDOG_TIMER] = reset_watchdog_timer,
>> -    [IPMI_CMD_SET_WATCHDOG_TIMER] = set_watchdog_timer,
>> -    [IPMI_CMD_GET_WATCHDOG_TIMER] = get_watchdog_timer,
>> +    [IPMI_CMD_GET_DEVICE_ID] = { get_device_id },
>> +    [IPMI_CMD_COLD_RESET] = { cold_reset },
>> +    [IPMI_CMD_WARM_RESET] = { warm_reset },
>> +    [IPMI_CMD_SET_ACPI_POWER_STATE] = { set_acpi_power_state, 4 },
>> +    [IPMI_CMD_GET_ACPI_POWER_STATE] = { get_acpi_power_state },
>> +    [IPMI_CMD_GET_DEVICE_GUID] = { get_device_guid },
>> +    [IPMI_CMD_SET_BMC_GLOBAL_ENABLES] = { set_bmc_global_enables, 3 },
>> +    [IPMI_CMD_GET_BMC_GLOBAL_ENABLES] = { get_bmc_global_enables },
>> +    [IPMI_CMD_CLR_MSG_FLAGS] = { clr_msg_flags, 3 },
>> +    [IPMI_CMD_GET_MSG_FLAGS] = { get_msg_flags },
>> +    [IPMI_CMD_GET_MSG] = { get_msg },
>> +    [IPMI_CMD_SEND_MSG] = { send_msg, 3 },
>> +    [IPMI_CMD_READ_EVT_MSG_BUF] = { read_evt_msg_buf },
>> +    [IPMI_CMD_RESET_WATCHDOG_TIMER] = { reset_watchdog_timer },
>> +    [IPMI_CMD_SET_WATCHDOG_TIMER] = { set_watchdog_timer, 8 },
>> +    [IPMI_CMD_GET_WATCHDOG_TIMER] = { get_watchdog_timer },
>>   };
>>   static const IPMINetfn app_netfn = {
>>       .cmd_nums = ARRAY_SIZE(app_cmds),
>> @@ -1667,18 +1654,18 @@ static const IPMINetfn app_netfn = {
>>   };
>>
>>   static const IPMICmdHandler storage_cmds[] = {
>> -    [IPMI_CMD_GET_SDR_REP_INFO] = get_sdr_rep_info,
>> -    [IPMI_CMD_RESERVE_SDR_REP] = reserve_sdr_rep,
>> -    [IPMI_CMD_GET_SDR] = get_sdr,
>> -    [IPMI_CMD_ADD_SDR] = add_sdr,
>> -    [IPMI_CMD_CLEAR_SDR_REP] = clear_sdr_rep,
>> -    [IPMI_CMD_GET_SEL_INFO] = get_sel_info,
>> -    [IPMI_CMD_RESERVE_SEL] = reserve_sel,
>> -    [IPMI_CMD_GET_SEL_ENTRY] = get_sel_entry,
>> -    [IPMI_CMD_ADD_SEL_ENTRY] = add_sel_entry,
>> -    [IPMI_CMD_CLEAR_SEL] = clear_sel,
>> -    [IPMI_CMD_GET_SEL_TIME] = get_sel_time,
>> -    [IPMI_CMD_SET_SEL_TIME] = set_sel_time,
>> +    [IPMI_CMD_GET_SDR_REP_INFO] = { get_sdr_rep_info },
>> +    [IPMI_CMD_RESERVE_SDR_REP] = { reserve_sdr_rep },
>> +    [IPMI_CMD_GET_SDR] = { get_sdr, 8 },
>> +    [IPMI_CMD_ADD_SDR] = { add_sdr },
>> +    [IPMI_CMD_CLEAR_SDR_REP] = { clear_sdr_rep, 8 },
>> +    [IPMI_CMD_GET_SEL_INFO] = { get_sel_info },
>> +    [IPMI_CMD_RESERVE_SEL] = { reserve_sel },
>> +    [IPMI_CMD_GET_SEL_ENTRY] = { get_sel_entry, 8 },
>> +    [IPMI_CMD_ADD_SEL_ENTRY] = { add_sel_entry, 18 },
>> +    [IPMI_CMD_CLEAR_SEL] = { clear_sel, 8 },
>> +    [IPMI_CMD_GET_SEL_TIME] = { get_sel_time, 6 },
>> +    [IPMI_CMD_SET_SEL_TIME] = { set_sel_time },
>>   };
>>
>>   static const IPMINetfn storage_netfn = {
>