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Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Q
From: |
andrzej zaborowski |
Subject: |
Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup |
Date: |
Sat, 25 Oct 2008 16:15:27 +0200 |
2008/10/25 Blue Swirl <address@hidden>:
> On 10/25/08, andrzej zaborowski <address@hidden> wrote:
>> 2008/10/25 Blue Swirl <address@hidden>:
>> > On 10/25/08, andrzej zaborowski <address@hidden> wrote:
>> >> 2008/10/25 Blue Swirl <address@hidden>:
>> >>
>> >> > Revision: 5532
>> >> >
>> http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5532
>> >> > Author: blueswir1
>> >> > Date: 2008-10-25 11:23:27 +0000 (Sat, 25 Oct 2008)
>> >> >
>> >> > Log Message:
>> >> > -----------
>> >> > Replace uses of strndup (a GNU extension) with Qemu pstrdup
>> >> >
>> >> > Modified Paths:
>> >> > --------------
>> >> > trunk/cutils.c
>> >> > trunk/hw/bt-hci.c
>> >> > trunk/qemu-common.h
>> >> >
>> >> > Modified: trunk/cutils.c
>> >> > ===================================================================
>> >> > --- trunk/cutils.c 2008-10-25 11:21:28 UTC (rev 5531)
>> >> > +++ trunk/cutils.c 2008-10-25 11:23:27 UTC (rev 5532)
>> >> > @@ -50,6 +50,18 @@
>> >> > return buf;
>> >> > }
>> >> >
>> >> > +/* strdup with a limit */
>> >> > +char *pstrdup(const char *str, size_t buf_size)
>> >> > +{
>> >> > + size_t len;
>> >> > + char *buf;
>> >> > +
>> >> > + len = MIN(buf_size, strlen(str));
>> >> > + buf = qemu_malloc(len);
>> >> > + pstrcpy(buf, len, str);
>> >> > + return buf;
>> >> > +}
>> >>
>> >>
>> >> I think here also pstrcpy will only copy up to buf_size - 1 characters
>> >> while strndup would copy buf_size chars.
>> >
>> > That is actually safer if we always want the strings to be NUL terminated.
>>
>>
>> strndup also always NUL terminates the string so it's just as safe,
>> the length is just different.
>>
>>
>> >
>> > But the allocation length is wrong, it should be MIN(buf_size,
>> strlen(str) + 1).
>>
>>
>> By my reading of the manual, it should rather be MIN(buf_size, strlen(str))
>> + 1.
>
> But then the length could be incorrect: buf_size + 1.
That's what it should be in case lmp_name is 248 chars long. I think
the confusion is because you called the parameter buf_size while
strndup calls it n (the number of characters.. not buffer size).
Note that you can use memcpy instead of pstrcpy because the length is
known so there's no need for the overhead.
Cheers
- [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, Blue Swirl, 2008/10/25
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, andrzej zaborowski, 2008/10/25
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, Blue Swirl, 2008/10/25
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, andrzej zaborowski, 2008/10/25
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, Blue Swirl, 2008/10/25
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup,
andrzej zaborowski <=
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, Blue Swirl, 2008/10/25
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, andrzej zaborowski, 2008/10/25
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, Blue Swirl, 2008/10/26
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, andrzej zaborowski, 2008/10/26
Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup, Warner Losh, 2008/10/25