bash/patches/bash-5.0-patch-5.patch

   1 From 41f5420db7a911fb0833be693205f4db41f05434 Mon Sep 17 00:00:00 2001
   2 From: Chet Ramey <chet.ramey@case.edu>
   3 Date: Sat, 20 Apr 2019 14:25:52 -0400
   4 Subject: [PATCH] Bash-5.0 patch 5: prevent optimizing forks away too
   5  aggressively
   6
   7 ---
   8  builtins/evalstring.c | 26 +++++++++++++++++++++++---
   9  command.h             |  1 +
  10  execute_cmd.c         |  2 ++
  11  patchlevel.h          |  2 +-
  12  4 files changed, 27 insertions(+), 4 deletions(-)
  13
  14 diff --git a/builtins/evalstring.c b/builtins/evalstring.c
  15 index 1496eeec..cadc9bc0 100644
  16 --- a/builtins/evalstring.c
  17 +++ b/builtins/evalstring.c
  18 @@ -100,12 +100,22 @@ should_suppress_fork (command)
  19           ((command->flags & CMD_INVERT_RETURN) == 0));
  20  }
  21
  22 +int
  23 +can_optimize_connection (command)
  24 +     COMMAND *command;
  25 +{
  26 +  return (*bash_input.location.string == '\0' &&
  27 +         (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') &&
  28 +         command->value.Connection->second->type == cm_simple);
  29 +}
  30 +
  31  void
  32  optimize_fork (command)
  33       COMMAND *command;
  34  {
  35    if (command->type == cm_connection &&
  36 -      (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR) &&
  37 +      (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') &&
  38 +      (command->value.Connection->second->flags & CMD_TRY_OPTIMIZING) &&
  39        should_suppress_fork (command->value.Connection->second))
  40      {
  41        command->value.Connection->second->flags |= CMD_NO_FORK;
  42 @@ -412,8 +422,18 @@ parse_and_execute (string, from_file, flags)
  43                   command->flags |= CMD_NO_FORK;
  44                   command->value.Simple->flags |= CMD_NO_FORK;
  45                 }
  46 -             else if (command->type == cm_connection)
  47 -               optimize_fork (command);
  48 +
  49 +             /* Can't optimize forks out here execept for simple commands.
  50 +                This knows that the parser sets up commands as left-side heavy
  51 +                (&& and || are left-associative) and after the single parse,
  52 +                if we are at the end of the command string, the last in a
  53 +                series of connection commands is
  54 +                command->value.Connection->second. */
  55 +             else if (command->type == cm_connection && can_optimize_connection (command))
  56 +               {
  57 +                 command->value.Connection->second->flags |= CMD_TRY_OPTIMIZING;
  58 +                 command->value.Connection->second->value.Simple->flags |= CMD_TRY_OPTIMIZING;
  59 +               }
  60  #endif /* ONESHOT */
  61
  62               /* See if this is a candidate for $( <file ). */
  63 diff --git a/command.h b/command.h
  64 index 32495162..b9e9b669 100644
  65 --- a/command.h
  66 +++ b/command.h
  67 @@ -186,6 +186,7 @@ typedef struct element {
  68  #define CMD_COPROC_SUBSHELL 0x1000
  69  #define CMD_LASTPIPE       0x2000
  70  #define CMD_STDPATH        0x4000      /* use standard path for command lookup */
  71 +#define CMD_TRY_OPTIMIZING  0x8000     /* try to optimize this simple command */
  72
  73  /* What a command looks like. */
  74  typedef struct command {
  75 diff --git a/execute_cmd.c b/execute_cmd.c
  76 index 8b3c83aa..f1d74bfe 100644
  77 --- a/execute_cmd.c
  78 +++ b/execute_cmd.c
  79 @@ -2767,6 +2767,8 @@ execute_connection (command, asynchronous, pipe_in, pipe_out, fds_to_close)
  80           ((command->value.Connection->connector == OR_OR) &&
  81            (exec_result != EXECUTION_SUCCESS)))
  82         {
  83 +         optimize_fork (command);
  84 +
  85           second = command->value.Connection->second;
  86           if (ignore_return && second)
  87             second->flags |= CMD_IGNORE_RETURN;
  88 diff --git a/patchlevel.h b/patchlevel.h
  89 index c059f0bd..1bc098b8 100644
  90 --- a/patchlevel.h
  91 +++ b/patchlevel.h
  92 @@ -25,6 +25,6 @@
  93     regexp `^#define[   ]*PATCHLEVEL', since that's what support/mkversion.sh
  94     looks for to find the patch level (for the sccs version string). */
  95
  96 -#define PATCHLEVEL 4
  97 +#define PATCHLEVEL 5
  98
  99  #endif /* _PATCHLEVEL_H_ */
 100 --
 101 2.17.2
 102