On Wed, 31 Jul 2024 11:29:41 +0200,
Amadeusz Sławiński wrote:
>
> On 7/31/2024 11:21 AM, Takashi Iwai wrote:
> > On Wed, 31 Jul 2024 10:46:08 +0200,
> > Amadeusz Sławiński wrote:
> >>
> >> On 6/19/2024 5:28 PM, Takashi Iwai wrote:
> >>> For making it easer for applications to create a virtual UMP Endpoint
> >>> and UMP blocks, add two API helper functions.
> >>>
> >>> snd_seq_create_ump_endpoint() creates (unsurprisingly) a UMP Endpoint,
> >>> based on the given snd_ump_endpoint_info_t information. The number of
> >>> (max) UMP groups belonging to this Endpoint has to be specified.
> >>> This function sets up the Endpoint info on the sequencer client, and
> >>> creates a MIDI 2.0 UMP port as well as UMP Group ports automatically.
> >>> The name of the sequencer client is updated from the Endpoint name,
> >>> too.
> >>>
> >>> After creating a UMP Endpoint, create each UMP Block via
> >>> snd_seq_create_ump_block() function with a snd_ump_block_info_t info.
> >>> The associated groups for each block have to be specified there.
> >>> The port names and capability bits are updated accordingly after
> >>> setting each block information.
> >>>
> >>> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> >>> ---
> >>
> >> ...
> >>
> >>> + if (*blknames) {
> >>> + strlcat(blknames, ", ", sizeof(blknames));
> >>> + strlcat(blknames, (const char *)bp->name,
> >>> + sizeof(blknames));
> >>
> >> FYI, this seems to introduce build problems on systems that do not
> >> have strlcpy:
> >>
> >> During build:
> >> seqmid.c: In function ‘update_group_ports’:
> >> seqmid.c:672:33: warning: implicit declaration of function
> >> ‘strlcat’; did you mean ‘strncat’?
> >> [-Wimplicit-function-declaration]
> >> 672 | strlcat(blknames, ", ",
> >> sizeof(blknames));
> >> | ^~~~~~~
> >> | strncat
> >>
> >> And then during linking:
> >> /usr/bin/ld: seq/.libs/libseq.a(seqmid.o): in function `update_group_ports':
> >> /home/amade/workdir/avs/alsa-lib/src/seq/seqmid.c:672: undefined
> >> reference to `strlcat'
> >> /usr/bin/ld: /home/amade/workdir/avs/alsa-lib/src/seq/seqmid.c:673:
> >> undefined reference to `strlcat'
> >> collect2: error: ld returned 1 exit status
> >
> > Thanks, I'll modify it to avoid strlcat() like below.
> >
> >
> > Takashi
> >
> > -- 8< --
> > Subject: [PATCH] seq: Avoid strlcat()
> >
> > strlcat() isn't available in every system, so better to avoid it.
> > Rewrite the code without strlcat().
> >
> > Fixes: 6167b8ce3e80 ("seq: Add API helper functions for creating UMP Endpoint and Blocks")
> > Link: https://lore.kernel.org/0796c157-1ac3-47a3-9d54-ba86f59d64d5@xxxxxxxxxxxxxxx
> > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> > ---
> > src/seq/seqmid.c | 12 ++++++------
> > 1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/src/seq/seqmid.c b/src/seq/seqmid.c
> > index 08c62d5c24b8..b30db4075254 100644
> > --- a/src/seq/seqmid.c
> > +++ b/src/seq/seqmid.c
> > @@ -635,6 +635,7 @@ static void update_group_ports(snd_seq_t *seq, snd_ump_endpoint_info_t *ep)
> > char blknames[64];
> > char name[64];
> > unsigned int caps = 0;
> > + int len;
> > blknames[0] = 0;
> > for (b = 0; b < ep->num_blocks; b++) {
> > @@ -668,14 +669,13 @@ static void update_group_ports(snd_seq_t *seq, snd_ump_endpoint_info_t *ep)
> > if (!*bp->name)
> > continue;
> > - if (*blknames) {
> > - strlcat(blknames, ", ", sizeof(blknames));
> > - strlcat(blknames, (const char *)bp->name,
> > - sizeof(blknames));
> > - } else {
> > + len = strlen(blknames);
> > + if (len)
> > + snprintf(blknames + len, sizeof(blknames) - len,
> > + ", %s", bp->name);
> > + else
> > snd_strlcpy(blknames, (const char *)bp->name,
> > sizeof(blknames));
> > - }
> > }
> > if (!*blknames)
>
> Builds now, but still gives warning:
>
> seqmid.c: In function ‘update_group_ports’:
> seqmid.c:675:45: warning: ‘%s’ directive output may be truncated
> writing up to 127 bytes into a region of size 61
> [-Wformat-truncation=]
> 675 | ", %s", bp->name);
> | ^~
> In file included from /usr/include/stdio.h:894,
> from ../../include/local.h:28,
> from seq_local.h:26,
> from seqmid.c:23:
> In function ‘snprintf’,
> inlined from ‘update_group_ports’ at seqmid.c:674:5:
> /usr/include/x86_64-linux-gnu/bits/stdio2.h:71:10: note:
> ‘__builtin___snprintf_chk’ output between 3 and 130 bytes into a
> destination of size 63
> 71 | return __builtin___snprintf_chk (__s, __n,
> __USE_FORTIFY_LEVEL - 1,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 72 | __glibc_objsize (__s), __fmt,
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 73 | __va_arg_pack ());
> | ~~~~~~~~~~~~~~~~~
The compiler gives too much false positives.
Takashi
