BASH PATCH REPORT
                            =================

Bash-Release:   5.2
Patch-ID:       bash52-015

Bug-Reported-by:        Frode Nordahl <[email protected]>
Bug-Reference-ID:       <[email protected]>
Bug-Reference-URL:      https://lists.gnu.org/archive/html/bug-bash/2022-11/msg00078.html

Bug-Description:

There are several cases where bash is too aggressive when optimizing out forks
in subshells. For example, `eval' and traps should never be optimized.

Patch (apply with `patch -p0'):

*** ../bash-5.2-patched/builtins/common.h       2022-11-23 17:09:18.000000000 -0500
--- builtins/common.h   2022-11-19 18:03:59.000000000 -0500
***************
*** 52,55 ****
--- 52,56 ----
 #define SEVAL_ONECMD  0x100           /* only allow a single command */
 #define SEVAL_NOHISTEXP       0x200           /* inhibit history expansion */
+ #define SEVAL_NOOPTIMIZE 0x400                /* don't try to set optimization flags */

 /* Flags for describe_command, shared between type.def and command.def */
*** ../bash-5.2-patched/builtins/evalstring.c   2022-11-05 17:27:44.000000000 -0400
--- builtins/evalstring.c       2022-11-19 18:23:21.000000000 -0500
***************
*** 133,138 ****
       (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') &&
       (command->value.Connection->second->flags & CMD_TRY_OPTIMIZING) &&
!       ((startup_state == 2 && should_suppress_fork (command->value.Connection->second)) ||
!        ((subshell_environment & SUBSHELL_PAREN) && should_optimize_fork (command->value.Connection->second, 0))))
     {
       command->value.Connection->second->flags |= CMD_NO_FORK;
--- 133,138 ----
       (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') &&
       (command->value.Connection->second->flags & CMD_TRY_OPTIMIZING) &&
!       (should_suppress_fork (command->value.Connection->second) ||
!       ((subshell_environment & SUBSHELL_PAREN) && should_optimize_fork (command->value.Connection->second, 0))))
     {
       command->value.Connection->second->flags |= CMD_NO_FORK;
***************
*** 291,294 ****
--- 291,295 ----
       (flags & SEVAL_RESETLINE) -> reset line_number to 1
       (flags & SEVAL_NOHISTEXP) -> history_expansion_inhibited -> 1
+       (flags & SEVAL_NOOPTIMIZE) -> don't try to turn on optimizing flags
 */

***************
*** 503,507 ****
                series of connection commands is
                command->value.Connection->second. */
!             else if (command->type == cm_connection && can_optimize_connection (command))
               {
                 command->value.Connection->second->flags |= CMD_TRY_OPTIMIZING;
--- 504,510 ----
                series of connection commands is
                command->value.Connection->second. */
!             else if (command->type == cm_connection &&
!                      (flags & SEVAL_NOOPTIMIZE) == 0 &&
!                      can_optimize_connection (command))
               {
                 command->value.Connection->second->flags |= CMD_TRY_OPTIMIZING;
*** ../bash-5.2-patched/builtins/eval.def       2016-01-25 13:28:37.000000000 -0500
--- builtins/eval.def   2022-11-19 18:04:25.000000000 -0500
***************
*** 54,57 ****
   list = loptend;     /* skip over possible `--' */

!   return (list ? evalstring (string_list (list), "eval", SEVAL_NOHIST) : EXECUTION_SUCCESS);
 }
--- 54,57 ----
   list = loptend;     /* skip over possible `--' */

!   return (list ? evalstring (string_list (list), "eval", SEVAL_NOHIST|SEVAL_NOOPTIMIZE) : EXECUTION_SUCCESS);
 }
*** ../bash-5.2-patched/trap.c  2022-08-10 08:59:45.000000000 -0400
--- trap.c      2022-12-12 10:57:51.000000000 -0500
***************
*** 305,308 ****
--- 305,309 ----
   volatile int save_return_catch_flag, function_code;
   procenv_t save_return_catch;
+   char *trap_command, *old_trap;
 #if defined (ARRAY_VARS)
   ARRAY *ps;
***************
*** 420,423 ****
--- 421,427 ----
         else
           {
+             old_trap = trap_list[sig];
+             trap_command = savestring (old_trap);
+
             save_parser_state (&pstate);
             save_subst_varlist = subst_assign_varlist;
***************
*** 442,446 ****

             if (function_code == 0)
!               x = parse_and_execute (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE);
             else
               {
--- 446,451 ----

             if (function_code == 0)
!               /* XXX is x always last_command_exit_value? */
!               x = parse_and_execute (trap_command, "trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE|SEVAL_NOOPTIMIZE);
             else
               {
***************
*** 1003,1007 ****
       {
         reset_parser ();
!         parse_and_execute (trap_command, "exit trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE);
       }
       else if (code == ERREXIT)
--- 1008,1012 ----
       {
         reset_parser ();
!         parse_and_execute (trap_command, "exit trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE|SEVAL_NOOPTIMIZE);
       }
       else if (code == ERREXIT)
***************
*** 1110,1114 ****
       }

!       flags = SEVAL_NONINT|SEVAL_NOHIST;
       if (sig != DEBUG_TRAP && sig != RETURN_TRAP && sig != ERROR_TRAP)
       flags |= SEVAL_RESETLINE;
--- 1115,1119 ----
       }

!       flags = SEVAL_NONINT|SEVAL_NOHIST|SEVAL_NOOPTIMIZE;
       if (sig != DEBUG_TRAP && sig != RETURN_TRAP && sig != ERROR_TRAP)
       flags |= SEVAL_RESETLINE;
*** ../bash-5.2-patched/parse.y 2022-11-23 17:09:18.000000000 -0500
--- parse.y     2022-11-19 18:15:34.000000000 -0500
***************
*** 2828,2832 ****
     last_lastarg = savestring (last_lastarg);

!   parse_and_execute (savestring (command), vname, SEVAL_NONINT|SEVAL_NOHIST);

   restore_parser_state (&ps);
--- 2844,2848 ----
     last_lastarg = savestring (last_lastarg);

!   parse_and_execute (savestring (command), vname, SEVAL_NONINT|SEVAL_NOHIST|SEVAL_NOOPTIMIZE);

   restore_parser_state (&ps);
*** ../bash-5.2-patched/jobs.c  2022-07-18 10:19:56.000000000 -0400
--- jobs.c      2022-11-19 18:10:24.000000000 -0500
***************
*** 4221,4225 ****
   for (i = 0; i < nchild; i++)
     {
!       parse_and_execute (savestring (trap_command), "trap", SEVAL_NOHIST|SEVAL_RESETLINE);
     }

--- 4243,4247 ----
   for (i = 0; i < nchild; i++)
     {
!       parse_and_execute (savestring (trap_command), "trap", SEVAL_NOHIST|SEVAL_RESETLINE|SEVAL_NOOPTIMIZE);
     }

*** ../bash-5.2-patched/y.tab.c 2022-11-23 17:09:18.000000000 -0500
--- y.tab.c     2022-11-23 17:21:17.000000000 -0500
***************
*** 5139,5143 ****
     last_lastarg = savestring (last_lastarg);

!   parse_and_execute (savestring (command), vname, SEVAL_NONINT|SEVAL_NOHIST);

   restore_parser_state (&ps);
--- 5154,5158 ----
     last_lastarg = savestring (last_lastarg);

!   parse_and_execute (savestring (command), vname, SEVAL_NONINT|SEVAL_NOHIST|SEVAL_NOOPTIMIZE);

   restore_parser_state (&ps);
*** ../bash-5.2-patched/execute_cmd.c   2022-11-05 17:27:41.000000000 -0400
--- execute_cmd.c       2022-11-22 17:09:38.000000000 -0500
***************
*** 1655,1659 ****
      and set CMD_TRY_OPTIMIZING for simple commands on the right side of an
      and-or or `;' list to test for optimizing forks when they are executed. */
!   if (user_subshell && command->type == cm_subshell)
     optimize_subshell_command (command->value.Subshell->command);

--- 1665,1670 ----
      and set CMD_TRY_OPTIMIZING for simple commands on the right side of an
      and-or or `;' list to test for optimizing forks when they are executed. */
!   if (user_subshell && command->type == cm_subshell &&
!       (command->flags & (CMD_TIME_PIPELINE|CMD_INVERT_RETURN)) == 0)
     optimize_subshell_command (command->value.Subshell->command);

*** ../bash-5.2/patchlevel.h    2020-06-22 14:51:03.000000000 -0400
--- patchlevel.h        2020-10-01 11:01:28.000000000 -0400
***************
*** 26,30 ****
    looks for to find the patch level (for the sccs version string). */

! #define PATCHLEVEL 14

 #endif /* _PATCHLEVEL_H_ */
--- 26,30 ----
    looks for to find the patch level (for the sccs version string). */

! #define PATCHLEVEL 15

 #endif /* _PATCHLEVEL_H_ */

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