Re: Odd behavior of "trap" and "functions" in 3.0-pre2

[Peter Stephenson <pws@ifh.de>]

schaefer@candle.brasslantern.com wrote:
> zagzig<14> trap "echo foo" USR2
> zagzig<17> grep TRAP <<(functions)
> TRAPALRM () {
> zagzig<18>
> 
> I'm almost certain that `functions` used to list all the TRAPxxx ....

Looks like the `trap' form of traps don't handle functions properly,
while the TRAPxxx functions do handle traps properly, so this is
certainly a mistake.  It seems the bin_trap() end of things got missed
out in some reorganisation.

I've tried to write this in such away as to maintain symmetry between
settrap() and unsettrap().  They now have a final argument which is
set to 1 if they should set/unset the corresponding function.  This is
necessary because the function code needs to be able to do its own
separate manipulations on the function.  The rule is therefore that
any call from outside the function-handling code should set the last
argument to 1 to maintain parallel trap/TRAPxxx settings.

Note there's no memory leak in the second last hunk:  the function,
the command list, and the name all needed to be separately allocated.

I fixed a related bug:

% TRAPUSR1() { }
% trap
TRAPUSR1() {}

When defining the function, you now need the space between the braces
because of the new brace rules (usually, anyway, and it never does any
harm).


There are still two function bugs, which are not trap-specific and
which I haven't fixed:

% TRAPUSR1() { }
% functions TRAPUSR1
TRAPUSR1()

No braces at all here:  that's illegal for a definition.
Any empty function does this.

Finally, if you do forget the space between the braces:

% TRAPUSR1() {}

No error is flagged, and the definition is:

% functions TRAPUSR1
TRAPUSR1() {
	{}
}

which crashes when you call it.  I can understand why `TRAPUSR1() { {}
}' would now produce this effect, but presumably parsing is going
astray with just the {}.

*** Src/builtin.c.settrap	Wed Jul 17 10:49:55 1996
--- Src/builtin.c	Fri Jul 26 10:00:16 1996
***************
*** 5432,5438 ****
  	for (sig = 0; sig < VSIGCOUNT; sig++)
  	    if (sigtrapped[sig])
  		if (!sigfuncs[sig])
! 		    printf("TRAP%s () {}\n", sigs[sig]);
  		else {
  		    s = getpermtext((void *) dupstruct((void *) sigfuncs[sig]));
  		    printf("TRAP%s () {\n\t%s\n}\n", sigs[sig], s);
--- 5432,5438 ----
  	for (sig = 0; sig < VSIGCOUNT; sig++)
  	    if (sigtrapped[sig])
  		if (!sigfuncs[sig])
! 		    printf("TRAP%s () { }\n", sigs[sig]);
  		else {
  		    s = getpermtext((void *) dupstruct((void *) sigfuncs[sig]));
  		    printf("TRAP%s () {\n\t%s\n}\n", sigs[sig], s);
***************
*** 5446,5455 ****
      if ((getsignum(*argv) != -1) || (!strcmp(*argv, "-") && argv++)) {
  	if (!*argv)
  	    for (sig = 0; sig < VSIGCOUNT; sig++)
! 		unsettrap(sig);
  	else
  	    while (*argv)
! 		unsettrap(getsignum(*argv++));
  	return 0;
      }
  
--- 5446,5455 ----
      if ((getsignum(*argv) != -1) || (!strcmp(*argv, "-") && argv++)) {
  	if (!*argv)
  	    for (sig = 0; sig < VSIGCOUNT; sig++)
! 		unsettrap(sig, 1);
  	else
  	    while (*argv)
! 		unsettrap(getsignum(*argv++), 1);
  	return 0;
      }
  
***************
*** 5469,5475 ****
  	    zwarnnam(name, "undefined signal: %s", *argv, 0);
  	    break;
  	}
! 	settrap(sig, l);
      }
      if (l)
  	popheap();
--- 5469,5475 ----
  	    zwarnnam(name, "undefined signal: %s", *argv, 0);
  	    break;
  	}
! 	settrap(sig, l, 1);
      }
      if (l)
  	popheap();
*** Src/exec.c.settrap	Fri Jul 26 09:28:20 1996
--- Src/exec.c	Fri Jul 26 09:42:59 1996
***************
*** 1799,1805 ****
  entersubsh(int how, int cl, int fake)
  {
      if (sigtrapped[SIGEXIT])
! 	unsettrap(SIGEXIT);
      if (unset(MONITOR)) {
  	if (how & Z_ASYNC) {
  	    sigtrapped[SIGINT] = 2;
--- 1799,1805 ----
  entersubsh(int how, int cl, int fake)
  {
      if (sigtrapped[SIGEXIT])
! 	unsettrap(SIGEXIT, 1);
      if (unset(MONITOR)) {
  	if (how & Z_ASYNC) {
  	    sigtrapped[SIGINT] = 2;
***************
*** 2355,2361 ****
  	    if (!strncmp(s, "TRAP", 4)) {
  		signum = getsignum(s + 4);
  		if (signum != -1)
! 		    settrap(signum, cmd->u.list);
  	    }
  	}
      } LASTALLOC;
--- 2355,2361 ----
  	    if (!strncmp(s, "TRAP", 4)) {
  		signum = getsignum(s + 4);
  		if (signum != -1)
! 		    settrap(signum, cmd->u.list, 0);
  	    }
  	}
      } LASTALLOC;
*** Src/hashtable.c.settrap	Fri Jul 26 09:28:29 1996
--- Src/hashtable.c	Fri Jul 26 09:42:59 1996
***************
*** 679,685 ****
  
      if ((hn = removehashnode(shfunctab, nam))) {
  	if (!strncmp(hn->nam, "TRAP", 4))
! 	    unsettrap(getsignum(hn->nam + 4));
  	return hn;
      } else
  	return NULL;
--- 679,685 ----
  
      if ((hn = removehashnode(shfunctab, nam))) {
  	if (!strncmp(hn->nam, "TRAP", 4))
! 	    unsettrap(getsignum(hn->nam + 4), 0);
  	return hn;
      } else
  	return NULL;
***************
*** 695,701 ****
  {
      hn->flags |= DISABLED;
      if (!strncmp(hn->nam, "TRAP", 4))
! 	unsettrap(getsignum(hn->nam + 4));
  }
  
  /* Re-enable an entry in the shell function hash table.  *
--- 695,701 ----
  {
      hn->flags |= DISABLED;
      if (!strncmp(hn->nam, "TRAP", 4))
! 	unsettrap(getsignum(hn->nam + 4), 0);
  }
  
  /* Re-enable an entry in the shell function hash table.  *
***************
*** 713,719 ****
      if (!strncmp(shf->nam, "TRAP", 4)) {
  	signum = getsignum(shf->nam + 4);
  	if (signum != -1)
! 	    settrap(signum, shf->funcdef);
      }
  }
  
--- 713,719 ----
      if (!strncmp(shf->nam, "TRAP", 4)) {
  	signum = getsignum(shf->nam + 4);
  	if (signum != -1)
! 	    settrap(signum, shf->funcdef, 0);
      }
  }
  
*** Src/signals.c.settrap	Fri Jul  5 15:50:48 1996
--- Src/signals.c	Fri Jul 26 09:51:25 1996
***************
*** 628,635 ****
  
  /**/
  void
! settrap(int sig, List l)
  {
      Cmd c;
   
      if (l && l->left && l->left->left) {
--- 628,640 ----
  
  /**/
  void
! settrap(int sig, List l, int addfunc)
  {
+     /*
+      * sig:     signal number to add trap for
+      * l:       the commands for the trap
+      * addfunc: if non-zero, add the corresponding TRAPxxx function too.
+      */
      Cmd c;
   
      if (l && l->left && l->left->left) {
***************
*** 668,679 ****
  	    sigfuncs[sig] = (List) dupstruct(l);
          } LASTALLOC;
      }
  }
  
  /**/
  void
! unsettrap(int sig)
  {
      if (sig == -1)
          return;
      if (jobbing && (sig == SIGTTOU || sig == SIGTSTP ||
--- 673,698 ----
  	    sigfuncs[sig] = (List) dupstruct(l);
          } LASTALLOC;
      }
+     if (addfunc)
+ 	PERMALLOC {
+ 	    char *trapf = (char *)zalloc(5 + strlen(sigs[sig]));
+ 	    Shfunc shf = zcalloc(sizeof *shf);
+ 
+ 	    sprintf(trapf, "TRAP%s", sigs[sig]);
+ 	    shf->funcdef = (List) dupstruct(l);
+ 	    shfunctab->addnode(shfunctab, trapf, shf);
+ 	} LASTALLOC;
  }
  
  /**/
  void
! unsettrap(int sig, int delfunc)
  {
+     /*
+      * sig:     signal number
+      * delfunc: non-zero if we are to delete the correspond TRAPxxx function
+      */
+ 
      if (sig == -1)
          return;
      if (jobbing && (sig == SIGTTOU || sig == SIGTSTP ||
***************
*** 699,704 ****
--- 718,732 ----
          freestruct(sigfuncs[sig]);
          sigfuncs[sig] = NULL;
      }
+     if (delfunc) {
+ 	char *signam = (char *)zalloc(strlen(sigs[sig])+5);
+ 	HashNode hn;
+ 
+ 	sprintf(signam, "TRAP%s", sigs[sig]);
+ 	if ((hn = shfunctab->removenode(shfunctab, signam)))
+ 	    shfunctab->freenode(hn);
+ 	free(signam);
+     }
  }
  
  /* Execute a trap function for a given signal */

-- 
Peter Stephenson <pws@ifh.de>       Tel: +49 33762 77366
WWW:  http://www.ifh.de/~pws/       Fax: +49 33762 77330
Deutches Electronen-Synchrotron --- Institut fuer Hochenergiephysik Zeuthen
DESY-IfH, 15735 Zeuthen, Germany.