shithub: riscv

Info  •  Files  •  Log  •  Branches

devproc: cleanup procwrite size checks

writes to /proc/n/notepg and /proc/n/note should be able to write
at ERRMAX-1 bytes, not ERRMAX-2.

simplify write to /proc/n/args by just copying to local buf first
and then doing a kstrdup(). the value of Proc.nargs does not matter
when Proc.setargs is 1.

--- a/sys/src/9/port/devproc.c

+++ b/sys/src/9/port/devproc.c

@@ -1154,10 +1154,9 @@

 static long

 procwrite(Chan *c, void *va, long n, vlong off)

 {

-	char buf[ERRMAX], *arg;

+	char buf[ERRMAX];

 	ulong offset;

 	Proc *p;

-	int m;

 	offset = off;

 	if(c->qid.type & QTDIR)

@@ -1165,7 +1164,7 @@

 	/* use the remembered noteid in the channel qid */

 	if(QID(c->qid) == Qnotepg) {

-		if(n >= ERRMAX-1)

+		if(n >= sizeof(buf))

 			error(Etoobig);

 		memmove(buf, va, n);

 		buf[n] = 0;

@@ -1184,20 +1183,12 @@

 	switch(QID(c->qid)){

 	case Qargs:

-		if(n == 0)

-			error(Eshort);

-		if(n >= ERRMAX)

+		if(offset != 0 || n >= sizeof(buf))

 			error(Etoobig);

-		arg = malloc(n+1);

-		if(arg == nil)

-			error(Enomem);

-		memmove(arg, va, n);

-		m = n;

-		if(arg[m-1] != 0)

-			arg[m++] = 0;

-		free(p->args);

-		p->args = arg;

-		p->nargs = m;

+		memmove(buf, va, n);

+		buf[n] = 0;

+		kstrdup(&p->args, buf);

+		p->nargs = 0;

 		p->setargs = 1;

 		break;

@@ -1241,7 +1232,7 @@

 		break;

 	case Qnoteid:

-		if(n >= sizeof(buf))

+		if(offset != 0 || n >= sizeof(buf))

 			error(Etoobig);

 		memmove(buf, va, n);

 		buf[n] = 0;