[PATCH v2 4/6] Use finfo structure to arbitrate overwrapped IOCTL command assignments between TTY and SND

[Dmitry V. Levin]

On Sat, Mar 12, 2022 at 03:02:07AM +0900, Masatake YAMATO wrote:
[...]
> +extern int
> +term_ioctl_decode_command_number(int code,
> +                struct tcb *tcp, struct finfo *finfo)
> +{
> +   /* See Documentation/admin-guide/devices.txt of
> +    * Linux kernel source tree about the number 3, 4, 5, 136 ~ 143.
> +    */
> +   if (finfo
> +       && finfo->type == finfo_dev_chr
> +       && ((136 <= finfo->dev.major && finfo->dev.major <= 143)
> +	   || (3 <= finfo->dev.major && finfo->dev.major <= 5))) {
> +       switch (code) {
> +       case TCSETSF:
> +	       tprints("TCSETSF");
> +	       return IOCTL_NUMBER_STOP_LOOKUP;
> +       case TCSETSW:
> +	       tprints("TCSETSW");
> +	       return IOCTL_NUMBER_STOP_LOOKUP;
> +       case TCSETS:
> +	       tprints("TCSETS");
> +	       return IOCTL_NUMBER_STOP_LOOKUP;
> +       case TCSETA:
> +	       tprints("TCSETA");
> +	       return IOCTL_NUMBER_STOP_LOOKUP;
> +       case TCSETAW:
> +	       tprints("TCSETAW");
> +	       return IOCTL_NUMBER_STOP_LOOKUP;
> +       case TCSETAF:
> +	       tprints("TCSETAF");
> +	       return IOCTL_NUMBER_STOP_LOOKUP;
> +       }
> +   }
> +   return 0;
> +}

Looks like this introduces regression in strace -X support.
For example, before this change we had
$ strace -Xverbose -eioctl stty sane            
ioctl(0, 0x5401 /* TCGETS */, {0xf /* B38400 */ opost isig icanon echo ...}) = 0
ioctl(0, 0x5403 /* SNDCTL_TMR_STOP or TCSETSW */, {0xf /* B38400 */ opost isig icanon echo ...}) = 0
ioctl(0, 0x5401 /* TCGETS */, {0xf /* B38400 */ opost isig icanon echo ...}) = 0

Also, the switch statement itself looks like an open-coding of printxval.


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