Re: [PATCH 4/4] [MAIN] Optimize dash -c "command" to avoid a fork

[Jonathan Nieder <jrnieder@xxxxxxxxx>]

Herbert Xu wrote:

> OK, what about this patch?

Neat.  Let's see:

> --- a/src/parser.c
> +++ b/src/parser.c
[...]
> @@ -210,6 +210,7 @@ list(int nlflag)
>  				parseheredoc();
>  			else
>  				pungetc();		/* push back EOF on input */
> +			tokpushback++;
>  			return n1;
>  		default:
>  			if (nlflag == 1)

This means to push back the TEOF instead of calling pgetc again and
again.  Should be safe.

By the way, is the pungetc() call needed?  I tried to provoke
misbehavior using here documents and reading from the terminal but
didn't manage to come up with a relevant scenario.

> --- a/src/parser.h
> +++ b/src/parser.h
> @@ -34,6 +34,8 @@
>   *	@(#)parser.h	8.3 (Berkeley) 5/4/95
>   */
>  
> +#include "token.h"

mksyntax #include-s parser.h, so after a "make clean":

	gcc -include ../config.h -DBSD=1 -DSHELL -DIFS_BROKEN  -g -Os -Wall -o mksyntax mksyntax.c
	In file included from mksyntax.c:43:0:
	parser.h:37:19: fatal error: token.h: No such file or directory

The following (on top) fixes it here.
---
 src/parser.c |    1 +
 src/parser.h |   11 +++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/parser.c b/src/parser.c
index 6de27629..9c0ef606 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -40,6 +40,7 @@
 
 #include "shell.h"
 #include "parser.h"
+#include "token.h"
 #include "nodes.h"
 #include "expand.h"	/* defines rmescapes() */
 #include "exec.h"	/* defines find_builtin() */
diff --git a/src/parser.h b/src/parser.h
index 2875cce6..8735890e 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -34,8 +34,6 @@
  *	@(#)parser.h	8.3 (Berkeley) 5/4/95
  */
 
-#include "token.h"
-
 /* control characters in argument strings */
 #define CTL_FIRST -127		/* first 'special' character */
 #define CTLESC -127		/* escape next character */
@@ -69,6 +67,15 @@
 #define CHKNL		0x4
 #define CHKEOFMARK	0x8
 
+/*
+ * TEOF is the eof-of-file token defined in token.h.  To avoid
+ * circular dependencies (we are used by mksyntax.c which generates
+ * token.h), repeat the definition here.  Good compilers will check
+ * that this definition matches the one from token.h when processing
+ * files such as parser.c that #include both.
+ */
+#define TEOF 0
+
 
 /*
  * NEOF is returned by parsecmd when it encounters an end of file.  It
-- 
1.7.6

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