Date: Tue, 5 Dec 1995 13:53:27 GMT From: nnd@itfs.nsk.su (Nickolay N. Dudorov) To: hackers@freebsd.org Subject: (Very) Old bug in /bin/sh (ash ?) Message-ID: <DJ4994.C2J@itfs.nsk.su>
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On all 'sh'-ells here (SysV.3.2, SunOS 4.1.3 etc)
construction:
{ a; b; c & d; e; }
is parsed and evaluated as a list of simple commands and one of
them (namely - c) is executed 'in background' or 'asynchronously'.
But on the FreeBSD systems (versions from 1.1 to 2.1)
it is parsed and evaluated as:
{ { a; b; c; } & { d; e; } }
Is this a BUG or a FEATURE ?
It seems to me that it is a bug in 'ash'. Following is a fix
for this misbehavior.
(This diff -u command was executed in /usr/src/bin/sh directory
on 2.1-STABLE sources SUP-ed until yesterday).
N.Dudorov
====================================================================
--- parser.c.ORG Tue Dec 5 16:15:52 1995
+++ parser.c Tue Dec 5 18:50:22 1995
@@ -149,30 +149,13 @@
n1 = andor();
for (;;) {
switch (readtoken()) {
- case TBACKGND:
- if (n1->type == NCMD || n1->type == NPIPE) {
- n1->ncmd.backgnd = 1;
- } else if (n1->type == NREDIR) {
- n1->type = NBACKGND;
- } else {
- n3 = (union node *)stalloc(sizeof (struct nredir));
- n3->type = NBACKGND;
- n3->nredir.n = n1;
- n3->nredir.redirect = NULL;
- n1 = n3;
- }
- goto tsemi;
case TNL:
- tokpushback++;
+ parseheredoc();
+ if (nlflag)
+ return n1;
/* fall through */
-tsemi: case TSEMI:
- if (readtoken() == TNL) {
- parseheredoc();
- if (nlflag)
- return n1;
- } else {
- tokpushback++;
- }
+ case TBACKGND:
+ case TSEMI:
checkkwd = 2;
if (tokendlist[peektoken()])
return n1;
@@ -212,6 +195,19 @@
} else if (t == TOR) {
t = NOR;
} else {
+ if (t == TBACKGND) {
+ if (n1->type == NCMD || n1->type == NPIPE) {
+ n1->ncmd.backgnd = 1;
+ } else if (n1->type == NREDIR) {
+ n1->type = NBACKGND;
+ } else {
+ n3 = (union node *)stalloc(sizeof (struct nredir));
+ n3->type = NBACKGND;
+ n3->nredir.n = n1;
+ n3->nredir.redirect = NULL;
+ n1 = n3;
+ }
+ }
tokpushback++;
return n1;
}
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