[PATCH 4/4] [VAR] Replace cmdenviron with localvars

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxxx>]

[VAR] Replace cmdenviron with localvars

This patch replaces the cmdenviron mechanism for temporary command
variables with the localvars mechanism used by functions.

This reduces code size, and more importantly, makes the variable
assignment take effect immediately as required by POSIX.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
---

 ChangeLog  |    4 ++++
 src/eval.c |   23 +++++++++--------------
 src/eval.h |    1 -
 src/var.c  |   45 ++++++++++++++++++++-------------------------
 src/var.h  |   15 +++++++++++++--
 5 files changed, 46 insertions(+), 42 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 1f7120f..bf1f13c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2010-05-26  Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
+
+	* Replace cmdenviron with localvars.
+
 2010-05-25  Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
 
 	* Fix poplocalvar leak.
diff --git a/src/eval.c b/src/eval.c
index 8d2767c..a6981a9 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -77,7 +77,6 @@ static int funcnest;		/* depth of function calls */
 
 
 char *commandname;
-struct strlist *cmdenviron;
 int exitstatus;			/* exit status of last command */
 int back_exitstatus;		/* exit status of backquoted command */
 
@@ -704,6 +703,7 @@ evalcommand(union node *cmd, int flags)
 	/* First expand the arguments. */
 	TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
 	setstackmark(&smark);
+	pushlocalvars();
 	back_exitstatus = 0;
 
 	cmdentry.cmdtype = CMDBUILTIN;
@@ -748,6 +748,8 @@ evalcommand(union node *cmd, int flags)
 		spp = varlist.lastp;
 		expandarg(argp, &varlist, EXP_VARTILDE);
 
+		mklocal((*spp)->text);
+
 		/*
 		 * Modify the command lookup path, if a PATH= assignment
 		 * is present
@@ -835,6 +837,7 @@ bail:
 			if (forkshell(jp, cmd, FORK_FG) != 0) {
 				exitstatus = waitforjob(jp);
 				INTON;
+				poplocalvars(0);
 				break;
 			}
 			FORCEINTON;
@@ -844,17 +847,9 @@ bail:
 		/* NOTREACHED */
 
 	case CMDBUILTIN:
-		cmdenviron = varlist.list;
-		if (cmdenviron) {
-			struct strlist *list = cmdenviron;
-			int i = VNOSET;
-			if (spclbltin > 0 || argc == 0) {
-				i = 0;
-				if (execcmd && argc > 1)
-					i = VEXPORT;
-			}
-			listsetvar(list, i);
-		}
+		poplocalvars(spclbltin > 0 || argc == 0);
+		if (execcmd && argc > 1)
+			listsetvar(varlist.list, VEXPORT);
 		if (evalbltin(cmdentry.u.cmd, argc, argv, flags)) {
 			int status;
 			int i;
@@ -875,7 +870,7 @@ raise:
 		break;
 
 	case CMDFUNCTION:
-		listsetvar(varlist.list, 0);
+		poplocalvars(1);
 		if (evalfun(cmdentry.u.func, argc, argv, flags))
 			goto raise;
 		break;
@@ -949,7 +944,7 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
 	shellparam.optoff = -1;
 	pushlocalvars();
 	evaltree(&func->n, flags & EV_TESTED);
-	poplocalvars();
+	poplocalvars(0);
 funcdone:
 	INTOFF;
 	funcnest--;
diff --git a/src/eval.h b/src/eval.h
index e190b28..ac394e8 100644
--- a/src/eval.h
+++ b/src/eval.h
@@ -37,7 +37,6 @@
 extern char *commandname;	/* currently executing command */
 extern int exitstatus;		/* exit status of last command */
 extern int back_exitstatus;	/* exit status of backquoted command */
-extern struct strlist *cmdenviron;  /* environment for builtin command */
 
 
 struct backcmd {		/* result of evalbackcmd */
diff --git a/src/var.c b/src/var.c
index 12f2f6c..40bd3fd 100644
--- a/src/var.c
+++ b/src/var.c
@@ -44,7 +44,6 @@
 #include "output.h"
 #include "expand.h"
 #include "nodes.h"	/* for other headers */
-#include "eval.h"	/* defines cmdenviron */
 #include "exec.h"
 #include "syntax.h"
 #include "options.h"
@@ -104,7 +103,6 @@ struct var varinit[] = {
 
 STATIC struct var *vartab[VTABSIZE];
 
-STATIC void mklocal(char *);
 STATIC struct var **hashvar(const char *);
 STATIC int vpcmp(const void *, const void *);
 STATIC struct var **findvar(struct var **, const char *);
@@ -147,7 +145,7 @@ INIT {
 
 RESET {
 	while (localvar_stack)
-		poplocalvars();
+		poplocalvars(0);
 }
 #endif
 
@@ -339,24 +337,6 @@ intmax_t lookupvarint(const char *name)
 
 
 /*
- * Search the environment of a builtin command.
- */
-
-char *
-bltinlookup(const char *name)
-{
-	struct strlist *sp;
-
-	for (sp = cmdenviron ; sp ; sp = sp->next) {
-		if (varequal(sp->text, name))
-			return strchrnul(sp->text, '=') + 1;
-	}
-	return lookupvar(name);
-}
-
-
-
-/*
  * Generate a list of variables satisfying the given conditions.
  */
 
@@ -486,8 +466,7 @@ localcmd(int argc, char **argv)
  * "-" as a special case.
  */
 
-STATIC void
-mklocal(char *name)
+void mklocal(char *name)
 {
 	struct localvar *lvp;
 	struct var **vpp;
@@ -534,7 +513,7 @@ mklocal(char *name)
  */
 
 void
-poplocalvars(void)
+poplocalvars(int keep)
 {
 	struct localvar_list *ll;
 	struct localvar *lvp, *next;
@@ -551,7 +530,23 @@ poplocalvars(void)
 		next = lvp->next;
 		vp = lvp->vp;
 		TRACE(("poplocalvar %s", vp ? vp->text : "-"));
-		if (vp == NULL) {	/* $- saved */
+		if (keep) {
+			int bits = VSTRFIXED;
+
+			if (lvp->flags != VUNSET) {
+				if (vp->text == lvp->text)
+					bits |= VTEXTFIXED;
+				else if (!(lvp->flags & (VTEXTFIXED|VSTACK)))
+					ckfree(lvp->text);
+			}
+
+			vp->flags &= ~bits;
+			vp->flags |= (lvp->flags & bits);
+
+			if ((vp->flags &
+			     (VEXPORT|VREADONLY|VSTRFIXED|VUNSET)) == VUNSET)
+				unsetvar(vp->text);
+		} else if (vp == NULL) {	/* $- saved */
 			memcpy(optlist, lvp->text, sizeof(optlist));
 			ckfree(lvp->text);
 			optschanged();
diff --git a/src/var.h b/src/var.h
index 2bb82b1..ef6d583 100644
--- a/src/var.h
+++ b/src/var.h
@@ -133,14 +133,14 @@ struct strlist;
 void listsetvar(struct strlist *, int);
 char *lookupvar(const char *);
 intmax_t lookupvarint(const char *);
-char *bltinlookup(const char *);
 char **listvars(int, int, char ***);
 #define environment() listvars(VEXPORT, VUNSET, 0)
 int showvars(const char *, int, int);
 int exportcmd(int, char **);
 int localcmd(int, char **);
+void mklocal(char *);
 void pushlocalvars(void);
-void poplocalvars(void);
+void poplocalvars(int);
 int unsetcmd(int, char **);
 void unsetvar(const char *);
 int varcmp(const char *, const char *);
@@ -148,3 +148,14 @@ int varcmp(const char *, const char *);
 static inline int varequal(const char *a, const char *b) {
 	return !varcmp(a, b);
 }
+
+/*
+ * Search the environment of a builtin command.
+ */
+
+static inline char *bltinlookup(const char *name)
+{
+	return lookupvar(name);
+}
+
+
--
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