Bug#547902: dash only reads the first character from pipe (bash reads whole line)
On Wed, Nov 18, 2009 at 10:13:48PM +0100, Moritz Muehlenhoff wrote:
> On Tue, Oct 13, 2009 at 11:13:01AM +0000, Gerrit Pape wrote:
> > tags 547902 + patch
> > quit
>
> [ Adding Christian to CC: ]
>
> Christian, did you submit your patch upstream?
No, not yet.
It still has the problem that reading the value(s) bytewise returns garbage
if the value(s) change during reading.
But I can try to send it to lkml and see what they say.
Shall I point to this bug-report and may I add a "Tested-by" line ?
Christian
>
> Cheers,
> Moritz
>
> > Hi, please see http://bugs.debian.org/547902
> >
> > Here's a patch from Christian Hohnstaedt <chohnstaedt@innominate.com>
> >
> > Thanks, Gerrit.
> >
> >
> > ---
> > Testparameter:
> > for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19; do dd if=/proc/sys/net/ipv4/tcp_wmem bs=$i 2>/dev/null; done
> >
> > for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19; do dd if=/proc/sys/net/ipv4/tcp_wmem skip=$i bs=1 2>/dev/null |wc -c ; done
> >
> > diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> > index 9270125..038df14 100644
> > --- a/kernel/sysctl.c
> > +++ b/kernel/sysctl.c
> > @@ -2117,17 +2117,16 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
> > #define TMPBUFLEN 21
> > int *i, vleft, first=1, neg, val;
> > unsigned long lval;
> > - size_t left, len;
> > + size_t left, len, off;
> >
> > char buf[TMPBUFLEN], *p;
> > char __user *s = buffer;
> >
> > - if (!tbl_data || !table->maxlen || !*lenp ||
> > - (*ppos && !write)) {
> > + if (!tbl_data || !table->maxlen || !*lenp) {
> > *lenp = 0;
> > return 0;
> > }
> > -
> > + off = 0;
> > i = (int *) tbl_data;
> > vleft = table->maxlen / sizeof(*i);
> > left = *lenp;
> > @@ -2176,25 +2175,31 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
> > if (conv(&neg, &lval, i, 1, data))
> > break;
> > } else {
> > + loff_t diff;
> > p = buf;
> > - if (!first)
> > - *p++ = '\t';
> > -
> > if (conv(&neg, &lval, i, 0, data))
> > break;
> >
> > - sprintf(p, "%s%lu", neg ? "-" : "", lval);
> > - len = strlen(buf);
> > - if (len > left)
> > - len = left;
> > - if(copy_to_user(s, buf, len))
> > - return -EFAULT;
> > - left -= len;
> > - s += len;
> > + len = sprintf(p, "%s%s%lu", first ? "" : "\t",
> > + neg ? "-" : "", lval);
> > + diff = *ppos - off;
> > + off += len;
> > + if (diff > 0 && diff < len) {
> > + p += diff;
> > + len -= diff;
> > + }
> > + if (off > *ppos) {
> > + if (len > left)
> > + len = left;
> > + if(copy_to_user(s, p, len))
> > + return -EFAULT;
> > + left -= len;
> > + s += len;
> > + }
> > }
> > }
> >
> > - if (!write && !first && left) {
> > + if (!write && !first && left && off >= *ppos) {
> > if(put_user('\n', s))
> > return -EFAULT;
> > left--, s++;
> >
> >
> >
Christian Hohnstaedt
--
Christian Hohnstaedt / Project Manager Hardware and Manufacturing
Innominate Security Technologies AG / protecting industrial networks
tel: +49.30.921028.208 / fax: +49.30.921028.020
Rudower Chaussee 13, D-12489 Berlin / http://www.innominate.com
Register Court: AG Charlottenburg, HR B 81603
Management Board: Dirk Seewald
Chairman of the Supervisory Board: Volker Bibelhausen
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