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Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Q
From: |
Blue Swirl |
Subject: |
Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup |
Date: |
Sat, 25 Oct 2008 17:31:39 +0300 |
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>:
> >> > 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).
If strlen(lmp_name) >= 248, only first 247 should be copied and the
final character should be NUL, because sizeof(read_local_name_rp.name)
== buf_size == 248.
> Note that you can use memcpy instead of pstrcpy because the length is
> known so there's no need for the overhead.
Right.
- [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, 2008/10/25
- Re: [Qemu-devel] [5532] Replace uses of strndup (a GNU extension) with Qemu pstrdup,
Blue Swirl <=
- 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