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kernel: be more careful about argc for /dev/drivers writes

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Not crashing on 'chdev &' is important.
This commit is contained in:
Jacob Moody 2022-05-28 17:23:41 +00:00
parent 01a6de812c
commit b75e549126
1 changed files with 7 additions and 3 deletions
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10
sys/src/9/port/devcons.c
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@ -705,18 +705,22 @@ conswrite(Chan *c, void *va, long n, vlong off)
error(Ebadarg); error(Ebadarg);
if(ct->index != CMchdev) if(ct->index != CMchdev)
error(Ebadarg); error(Ebadarg);
if(cb->nf < 2 || cb->nf > 3) if(cb->nf == 1)
error(Ebadarg); error(Ebadarg);
invert = 1; invert = 1;
a = cb->f[2]; a = "";
switch(cb->f[1][0]){ switch(cb->f[1][0]){
case '&': case '&':
if(cb->nf != 3)
error(Ebadarg);
a = cb->f[2];
if(cb->f[1][1] == '~') if(cb->f[1][1] == '~')
invert--; invert--;
break; break;
case '~': case '~':
a = ""; if(cb->nf != 2)
error(Ebadarg);
break; break;
default: default:
error(Ebadarg); error(Ebadarg);