Re: [Qemu-devel] [PATCH V2 3/6] libqblock error handling

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2012-9-12 4:32, Blue Swirl 写道:
> On Mon, Sep 10, 2012 at 8:26 AM, Wenchao Xia <xiawenc@linux.vnet.ibm.com> wrote:
>>    This patch contains error handling APIs, which user could call them to
>> get error details.
>>
>> Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
>> ---
>>   libqblock/libqblock-error.c |   60 +++++++++++++++++++++++++++++++++++++++++++
>>   libqblock/libqblock-error.h |   50 +++++++++++++++++++++++++++++++++++
>>   2 files changed, 110 insertions(+), 0 deletions(-)
>>   create mode 100644 libqblock/libqblock-error.c
>>   create mode 100644 libqblock/libqblock-error.h
>>
>> diff --git a/libqblock/libqblock-error.c b/libqblock/libqblock-error.c
>> new file mode 100644
>> index 0000000..d5ebabf
>> --- /dev/null
>> +++ b/libqblock/libqblock-error.c
>> @@ -0,0 +1,60 @@
>> +/*
>> + * QEMU block layer library
>> + *
>> + * Copyright IBM, Corp. 2012
>> + *
>> + * Authors:
>> + *  Wenchao Xia   <xiawenc@linux.vnet.ibm.com>
>> + *
>> + * This work is licensed under the terms of the GNU LGPL, version 2 or later.
>> + * See the COPYING.LIB file in the top-level directory.
>> + *
>> + */
>> +
>> +#include "libqblock-error.h"
>> +#include "libqblock-internal.h"
>> +
>> +void qb_error_get_human_str(struct QBroker *broker,
>> +                            char *buf, int buf_size)
>
> size_t buf_size
>
   OK.

>> +{
>> +    const char *err_ret_str;
>> +    switch (broker->err_ret) {
>> +    case QB_ERR_MEM_ERR:
>> +        err_ret_str = "Not enough memory.";
>> +        break;
>> +    case QB_ERR_INTERNAL_ERR:
>> +        err_ret_str = "Internal error.";
>> +        break;
>> +    case QB_ERR_INVALID_PARAM:
>> +        err_ret_str = "Invalid param.";
>> +        break;
>> +    case QB_ERR_BLOCK_OUT_OF_RANGE:
>> +        err_ret_str = "request is out of image's range.";
>> +        break;
>> +    default:
>> +        err_ret_str = "Unknow error.";
>> +        break;
>> +    }
>> +    if (broker == NULL) {
>> +        snprintf(buf, buf_size, "%s", err_ret_str);
>> +        return;
>> +    }
>> +
>> +    if (broker->err_ret == QB_ERR_INTERNAL_ERR) {
>> +        snprintf(buf, buf_size, "%s %s errno [%d]. strerror [%s].",
>> +                     err_ret_str, broker->err_msg,
>> +                     broker->err_no, strerror(-broker->err_no));
>> +    } else {
>> +        snprintf(buf, buf_size, "%s %s",
>> +                     err_ret_str, broker->err_msg);
>> +    }
>
> Please NUL terminate the string.
>
   snprintf will add "\0" automatically, could u explain more about this?

>> +    return;
>> +}
>> +
>> +int qb_error_get_errno(struct QBroker *broker)
>> +{
>> +    if (broker->err_ret == QB_ERR_INTERNAL_ERR) {
>> +        return broker->err_no;
>> +    }
>> +    return 0;
>> +}
>> diff --git a/libqblock/libqblock-error.h b/libqblock/libqblock-error.h
>> new file mode 100644
>> index 0000000..0690cfb
>> --- /dev/null
>> +++ b/libqblock/libqblock-error.h
>> @@ -0,0 +1,50 @@
>> +/*
>> + * QEMU block layer library
>> + *
>> + * Copyright IBM, Corp. 2012
>> + *
>> + * Authors:
>> + *  Wenchao Xia   <xiawenc@linux.vnet.ibm.com>
>> + *
>> + * This work is licensed under the terms of the GNU LGPL, version 2 or later.
>> + * See the COPYING.LIB file in the top-level directory.
>> + *
>> + */
>> +
>> +#ifndef LIBQBLOCK_ERROR
>> +#define LIBQBLOCK_ERROR
>> +
>> +#include "libqblock-types.h"
>> +
>> +#define QB_ERR_MEM_ERR (-1)
>> +#define QB_ERR_INTERNAL_ERR (-2)
>> +#define QB_ERR_INVALID_PARAM (-3)
>> +#define QB_ERR_BLOCK_OUT_OF_RANGE (-100)
>> +
>> +/* error handling */
>> +/**
>> + * qb_error_get_human_str: get human readable error string.
>> + *
>> + * return a human readable string, it would be truncated if buf is not big
>> + *  enough.
>> + *
>> + * @broker: operation broker, must be valid.
>> + * @buf: buf to receive the string.
>> + * @buf_size: the size of the string buf.
>> + */
>> +DLL_PUBLIC
>> +void qb_error_get_human_str(struct QBroker *broker,
>> +                            char *buf, int buf_size);
>> +
>> +/**
>> + * qb_error_get_errno: get error number, only valid when err_ret is
>> + *   QB_ERR_INTERNAL_ERR.
>> + *
>> + * return negative errno or 0 if last error is not QB_ERR_INTERNAL_ERR.
>> + *
>> + * @broker: operation broker.
>> + */
>> +DLL_PUBLIC
>> +int qb_error_get_errno(struct QBroker *broker);
>> +
>> +#endif
>> --
>> 1.7.1
>>
>>
>


-- 
Best Regards

Wenchao Xia