103 lines
3.7 KiB
Diff
103 lines
3.7 KiB
Diff
From 41f5420db7a911fb0833be693205f4db41f05434 Mon Sep 17 00:00:00 2001
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From: Chet Ramey <chet.ramey@case.edu>
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Date: Sat, 20 Apr 2019 14:25:52 -0400
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Subject: [PATCH] Bash-5.0 patch 5: prevent optimizing forks away too
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aggressively
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---
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builtins/evalstring.c | 26 +++++++++++++++++++++++---
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command.h | 1 +
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execute_cmd.c | 2 ++
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patchlevel.h | 2 +-
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4 files changed, 27 insertions(+), 4 deletions(-)
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diff --git a/builtins/evalstring.c b/builtins/evalstring.c
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index 1496eeec..cadc9bc0 100644
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--- a/builtins/evalstring.c
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+++ b/builtins/evalstring.c
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@@ -100,12 +100,22 @@ should_suppress_fork (command)
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((command->flags & CMD_INVERT_RETURN) == 0));
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}
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+int
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+can_optimize_connection (command)
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+ COMMAND *command;
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+{
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+ return (*bash_input.location.string == '\0' &&
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+ (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') &&
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+ command->value.Connection->second->type == cm_simple);
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+}
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+
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void
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optimize_fork (command)
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COMMAND *command;
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{
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if (command->type == cm_connection &&
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- (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR) &&
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+ (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') &&
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+ (command->value.Connection->second->flags & CMD_TRY_OPTIMIZING) &&
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should_suppress_fork (command->value.Connection->second))
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{
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command->value.Connection->second->flags |= CMD_NO_FORK;
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@@ -412,8 +422,18 @@ parse_and_execute (string, from_file, flags)
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command->flags |= CMD_NO_FORK;
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command->value.Simple->flags |= CMD_NO_FORK;
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}
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- else if (command->type == cm_connection)
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- optimize_fork (command);
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+
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+ /* Can't optimize forks out here execept for simple commands.
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+ This knows that the parser sets up commands as left-side heavy
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+ (&& and || are left-associative) and after the single parse,
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+ if we are at the end of the command string, the last in a
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+ series of connection commands is
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+ command->value.Connection->second. */
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+ else if (command->type == cm_connection && can_optimize_connection (command))
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+ {
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+ command->value.Connection->second->flags |= CMD_TRY_OPTIMIZING;
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+ command->value.Connection->second->value.Simple->flags |= CMD_TRY_OPTIMIZING;
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+ }
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#endif /* ONESHOT */
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/* See if this is a candidate for $( <file ). */
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diff --git a/command.h b/command.h
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index 32495162..b9e9b669 100644
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--- a/command.h
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+++ b/command.h
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@@ -186,6 +186,7 @@ typedef struct element {
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#define CMD_COPROC_SUBSHELL 0x1000
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#define CMD_LASTPIPE 0x2000
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#define CMD_STDPATH 0x4000 /* use standard path for command lookup */
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+#define CMD_TRY_OPTIMIZING 0x8000 /* try to optimize this simple command */
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/* What a command looks like. */
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typedef struct command {
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diff --git a/execute_cmd.c b/execute_cmd.c
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index 8b3c83aa..f1d74bfe 100644
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--- a/execute_cmd.c
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+++ b/execute_cmd.c
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@@ -2767,6 +2767,8 @@ execute_connection (command, asynchronous, pipe_in, pipe_out, fds_to_close)
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((command->value.Connection->connector == OR_OR) &&
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(exec_result != EXECUTION_SUCCESS)))
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{
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+ optimize_fork (command);
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+
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second = command->value.Connection->second;
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if (ignore_return && second)
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second->flags |= CMD_IGNORE_RETURN;
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diff --git a/patchlevel.h b/patchlevel.h
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index c059f0bd..1bc098b8 100644
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--- a/patchlevel.h
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+++ b/patchlevel.h
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@@ -25,6 +25,6 @@
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regexp `^#define[ ]*PATCHLEVEL', since that's what support/mkversion.sh
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looks for to find the patch level (for the sccs version string). */
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-#define PATCHLEVEL 4
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+#define PATCHLEVEL 5
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#endif /* _PATCHLEVEL_H_ */
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--
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2.17.2
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