Re: ksh(1): manual says $PPID is read-only

2016-09-08 Thread Todd C. Miller 
I've committed my fix to make "typeset -ir PPID" work and adjusted
the PPID line in initcoms[] accordingly.

 - todd

Re: ksh(1): manual says $PPID is read-only

2016-09-08 Thread Todd C. Miller 
On Thu, 08 Sep 2016 17:33:37 +0200, Theo Buehler wrote:

> Your fix looks correct to me and accomplishes the desired effect. Should
> we perhaps introduce
> 
> #define NO_RO_CHECK 0x4
> 
> and replace the 5 occurrences of the magic number in var.c?

Yes, I would like that.

 - todd

Re: ksh(1): manual says $PPID is read-only

2016-09-08 Thread Theo Buehler 
On Thu, Sep 08, 2016 at 09:22:28AM -0600, Todd C. Miller wrote:
> On Thu, 08 Sep 2016 10:08:23 -0400, Anthony Coulter wrote:
> 
> > We can fix either the manual or ksh itself; this diff takes the latter
> > approach. It is tempting to do this with "typeset -ir PPID" but that
> > actually doesn't work:
> > 
> > $ FOO=123
> > $ typeset -ir FOO
> > ksh: FOO: is read only
> 
> Perhaps we should fix the above issue as well, other ksh versions
> don't throw an error there.  Below is a simple fix, though a bit
> gross due to the magic 0x4.

Your fix looks correct to me and accomplishes the desired effect. Should
we perhaps introduce

#define NO_RO_CHECK 0x4

and replace the 5 occurrences of the magic number in var.c?

Re: ksh(1): manual says $PPID is read-only

2016-09-08 Thread Todd C. Miller 
On Thu, 08 Sep 2016 10:08:23 -0400, Anthony Coulter wrote:

> We can fix either the manual or ksh itself; this diff takes the latter
> approach. It is tempting to do this with "typeset -ir PPID" but that
> actually doesn't work:
> 
>   $ FOO=123
>   $ typeset -ir FOO
>   ksh: FOO: is read only

Perhaps we should fix the above issue as well, other ksh versions
don't throw an error there.  Below is a simple fix, though a bit
gross due to the magic 0x4.

 - todd

Index: bin/ksh/var.c
===
RCS file: /cvs/src/bin/ksh/var.c,v
retrieving revision 1.55
diff -u -p -u -r1.55 var.c
--- bin/ksh/var.c   30 Dec 2015 09:07:00 -  1.55
+++ bin/ksh/var.c   8 Sep 2016 15:20:20 -
@@ -661,6 +661,7 @@ typeset(const char *var, int set, int cl
 */
for (t = vpbase; t; t = t->u.array) {
int fake_assign;
+   int error_ok = KSH_RETURN_ERROR;
char *s = NULL;
char *free_me = NULL;
 
@@ -683,6 +684,10 @@ typeset(const char *var, int set, int cl
t->type = 0;
t->flag &= ~ALLOC;
}
+   if (!(t->flag & RDONLY) && (set & RDONLY)) {
+   /* allow var to be initialized read-only */
+   error_ok |= 0x4;
+   }
t->flag = (t->flag | set) & ~clr;
/* Don't change base if assignment is to be done,
 * in case assignment fails.
@@ -692,7 +697,7 @@ typeset(const char *var, int set, int cl
if (set & (LJUST|RJUST|ZEROFIL))
t->u2.field = field;
if (fake_assign) {
-   if (!setstr(t, s, KSH_RETURN_ERROR)) {
+   if (!setstr(t, s, error_ok)) {
/* Somewhat arbitrary action here:
 * zap contents of variable, but keep
 * the flag settings.

Re: ksh(1): manual says $PPID is read-only

2016-09-08 Thread Theo Buehler 
On Thu, Sep 08, 2016 at 10:08:23AM -0400, Anthony Coulter wrote:

[..]

> We can fix either the manual or ksh itself; this diff takes the latter
> approach. It is tempting to do this with "typeset -ir PPID" but that
> actually doesn't work:
> 
>   $ FOO=123
>   $ typeset -ir FOO
>   ksh: FOO: is read only
$ echo $FOO

$

This looks like a bug to me. Note that

$ typeset -ir BAR=123

does the expected thing:

$ BAR=1
ksh: BAR: is read only
$ echo $BAR
123

So, while I agree that PPID should be read-only and your patch appears
to accomplish the desired effect, I think we should try to fix the
underlying problem, not work around it.

ksh(1): manual says $PPID is read-only

2016-09-08 Thread Anthony Coulter 
The ksh(1) manual says that PPID should be read-only. But:

$ man ksh | grep PPID 
  PPID   The process ID of the shell's parent (read-only).
$ echo ${PPID}
5967
$ PPID=123
$ echo ${PPID}
123

We can fix either the manual or ksh itself; this diff takes the latter
approach. It is tempting to do this with "typeset -ir PPID" but that
actually doesn't work:

$ FOO=123
$ typeset -ir FOO
ksh: FOO: is read only

So we fix this by putting "typeset -r PPID" on its own line. One could
imagine shortening the section below with something like:

"typeset", "-i", "PPID", "OPTIND=1", NULL,
"typeset", "-r", "KSH_VERSION", "PPID", NULL,
"typeset", "-x", "SHELL", "PATH", "HOME", NULL,

but that involves some reordering: the -i's MUST come before the -r's.

Index: bin/ksh/main.c
===
RCS file: /open/anoncvs/cvs/src/bin/ksh/main.c,v
retrieving revision 1.79
diff -u -p -r1.79 main.c
--- main.c  4 Mar 2016 15:11:06 -   1.79
+++ main.c  8 Sep 2016 13:17:29 -
@@ -85,6 +85,7 @@ static const char *initcoms [] = {
"typeset", "-r", "KSH_VERSION", NULL,
"typeset", "-x", "SHELL", "PATH", "HOME", NULL,
"typeset", "-i", "PPID", NULL,
+   "typeset", "-r", "PPID", NULL,
"typeset", "-i", "OPTIND=1", NULL,
"eval", "typeset -i RANDOM MAILCHECK=\"${MAILCHECK-600}\" 
SECONDS=\"${SECONDS-0}\" TMOUT=\"${TMOUT-0}\"", NULL,
"alias",