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Deal with inflate() returning avail_in == avail_out == 0

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We must call inflate again in case there's any pending output
despite our input buffer being empty.  If the output buffer
is in fact already flushed, inflate() returns Z_BUF_ERROR.
There isn't really an error !
This commit is contained in:
brian 1997-12-08 20:22:12 +00:00
parent 3e011f4579
commit 390f8e60bd
1 changed files with 18 additions and 2 deletions
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20
usr.sbin/ppp/deflate.c
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@ -1,5 +1,5 @@
/*
* $Id: deflate.c,v 1.1 1997/12/03 10:23:45 brian Exp $
* $Id: deflate.c,v 1.2 1997/12/03 23:27:57 brian Exp $
*/
#include <sys/param.h>
@ -299,7 +299,7 @@ DeflateInput(u_short *proto, struct mbuf *mi)
static void
DeflateDictSetup(u_short proto, struct mbuf *mi)
{
int res, flush;
int res, flush, expect_error;
u_char *rp;
struct mbuf *mi_head;
short len;
@ -336,11 +336,14 @@ DeflateDictSetup(u_short proto, struct mbuf *mi)
InputState.cx.next_out = garbage;
InputState.cx.avail_out = sizeof garbage;
flush = Z_NO_FLUSH;
expect_error = 0;
while (1) {
if ((res = inflate(&InputState.cx, flush)) != Z_OK) {
if (res == Z_STREAM_END)
break; /* Done */
if (expect_error && res == Z_BUF_ERROR)
break;
LogPrintf(LogERROR, "DeflateDictSetup: inflate returned %d (%s)\n",
res, InputState.cx.msg ? InputState.cx.msg : "");
LogPrintf(LogERROR, "DeflateDictSetup: avail_in %d, avail_out %d\n",
@ -362,6 +365,19 @@ DeflateDictSetup(u_short proto, struct mbuf *mi)
}
if (InputState.cx.avail_out == 0) {
if (InputState.cx.avail_in == 0)
/*
* This seems to be a bug in libz ! If inflate() finished
* with 0 avail_in and 0 avail_out *and* this is the end of
* our input *and* inflate() *has* actually written all the
* output it's going to, it *doesn't* return Z_STREAM_END !
* When we subsequently call it with no more input, it gives
* us Z_BUF_ERROR :-( It seems pretty safe to ignore this
* error (the dictionary seems to stay in sync). In the worst
* case, we'll drop the next compressed packet and do a
* CcpReset() then.
*/
expect_error = 1;
/* overflow */
InputState.cx.next_out = garbage;
InputState.cx.avail_out = sizeof garbage;