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Re: [PATCH] gcc/config/nios2/nios2.c: Let custom_builtin_name[*] always be zero terminated string

On 07/26/2014 02:32 PM, Chung-Lin Tang wrote:
> On 14/7/26 11:28 AM, Chen Gang wrote:
>> The related strncpy() for custom_builtin_name[*] may set 5 none-zero
>> characters, which may cause custom_builtin_name[*] is none-zero
>> terminated.
>> So add additional '\0' byte for custom_builtin_name[*].
> Where did you see this? Supposedly the snprintf of the custom function
> type string should at most be of 'xnxx' format; 4 characters at most,

I guess, your 'xnxx' means "%cn%c%c", not "%sn%s%s" (which is current
implementation), also at present, "32 - n" is 17, not 4 for snprintf()
length limitation.

If we are always sure it must be no more than 4 characters (at present,
it is, but in the future, I don't know). We can use strcpy() instead of
strncpy() for it -- that will let other readers no doubt.

If we need let custom_builtin_name[*] not only zero terminated, but also
zero pad, we need pass '4' to strncpy() instead of '5', that also will
clear all doubts.

> not 5.  Do you have a test case where the behavior you described appears?

I find it by reading source code, for me, it is simple code, test is
welcomed, but not mandatory.

But it really needs necessary discussion (for modification, and comments).

Chen Gang

Open, share, and attitude like air, water, and life which God blessed

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