ash: fix handling of duplicate "local"

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

4 files changed, 42 insertions, 17 deletions

diff --git a/shell/ash.c b/shell/ash.c
index b568013b4..697a64fea 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2030,7 +2030,7 @@ varcmp(const char *p, const char *q)
         int c, d;
 
         while ((c = *p) == (d = *q)) {
-                if (!c || c == '=')
+                if (c == '\0' || c == '=')
                         goto out;
                 p++;
                 q++;
@@ -2247,7 +2247,7 @@ setvar(const char *name, const char *val, int flags)
 }
 
 static void FAST_FUNC
-setvar2(const char *name, const char *val)
+setvar0(const char *name, const char *val)
 {
         setvar(name, val, 0);
 }
@@ -2310,7 +2310,7 @@ unsetvar(const char *s)
                         free(vp);
                         INT_ON;
                 } else {
-                        setvar2(s, 0);
+                        setvar0(s, NULL);
                         vp->flags &= ~VEXPORT;
                 }
  ok:
@@ -5505,7 +5505,7 @@ ash_arith(const char *s)
         arith_t result;
 
         math_state.lookupvar = lookupvar;
-        math_state.setvar    = setvar2;
+        math_state.setvar    = setvar0;
         //math_state.endofname = endofname;
 
         INT_OFF;
@@ -6360,7 +6360,7 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
 
         switch (subtype) {
         case VSASSIGN:
-                setvar2(varname, startp);
+                setvar0(varname, startp);
                 amount = startp - expdest;
                 STADJUST(amount, expdest);
                 return startp;
@@ -8591,7 +8591,7 @@ evalfor(union node *n, int flags)
         loopnest++;
         flags &= EV_TESTED;
         for (sp = arglist.list; sp; sp = sp->next) {
-                setvar2(n->nfor.var, sp->text);
+                setvar0(n->nfor.var, sp->text);
                 evaltree(n->nfor.body, flags);
                 if (evalskip) {
                         if (evalskip == SKIPCONT && --skipcount <= 0) {
@@ -8970,21 +8970,37 @@ mklocal(char *name)
         struct localvar *lvp;
         struct var **vpp;
         struct var *vp;
+        char *eq = strchr(name, '=');
 
         INT_OFF;
-        lvp = ckzalloc(sizeof(struct localvar));
+        /* Cater for duplicate "local". Examples:
+         * x=0; f() { local x=1; echo $x; local x; echo $x; }; f; echo $x
+         * x=0; f() { local x=1; echo $x; local x=2; echo $x; }; f; echo $x
+         */
+        lvp = localvars;
+        while (lvp) {
+                if (varcmp(lvp->vp->var_text, name) == 0) {
+                        if (eq)
+                                setvareq(name, 0);
+                        /* else:
+                         * it's a duplicate "local VAR" declaration, do nothing
+                         */
+                        return;
+                }
+                lvp = lvp->next;
+        }
+
+        lvp = ckzalloc(sizeof(*lvp));
         if (LONE_DASH(name)) {
                 char *p;
                 p = ckmalloc(sizeof(optlist));
                 lvp->text = memcpy(p, optlist, sizeof(optlist));
                 vp = NULL;
         } else {
-                char *eq;
-
                 vpp = hashvar(name);
                 vp = *findvar(vpp, name);
-                eq = strchr(name, '=');
                 if (vp == NULL) {
+                        /* variable did not exist yet */
                         if (eq)
                                 setvareq(name, VSTRFIXED);
                         else
@@ -8994,12 +9010,15 @@ mklocal(char *name)
                 } else {
                         lvp->text = vp->var_text;
                         lvp->flags = vp->flags;
+                        /* make sure neither "struct var" nor string gets freed
+                         * during (un)setting:
+                         */
                         vp->flags |= VSTRFIXED|VTEXTFIXED;
                         if (eq)
                                 setvareq(name, 0);
                         else
                                 /* "local VAR" unsets VAR: */
-                                setvar(name, NULL, 0);
+                                setvar0(name, NULL);
                 }
         }
         lvp->vp = vp;
@@ -9491,7 +9510,7 @@ evalcommand(union node *cmd, int flags)
                  * '_' in 'vi' command mode during line editing...
                  * However I implemented that within libedit itself.
                  */
-                setvar2("_", lastarg);
+                setvar0("_", lastarg);
         }
         popstackmark(&smark);
 }
@@ -12885,7 +12904,7 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
          * to jump out of it.
          */
         INT_OFF;
-        r = shell_builtin_read(setvar2,
+        r = shell_builtin_read(setvar0,
                 argptr,
                 bltinlookup("IFS"), /* can be NULL */
                 read_flags,
@@ -13046,14 +13065,14 @@ init(void)
                         }
                 }
 
-                setvar2("PPID", utoa(getppid()));
+                setvar0("PPID", utoa(getppid()));
 #if ENABLE_ASH_BASH_COMPAT
                 p = lookupvar("SHLVL");
                 setvar("SHLVL", utoa((p ? atoi(p) : 0) + 1), VEXPORT);
                 if (!lookupvar("HOSTNAME")) {
                         struct utsname uts;
                         uname(&uts);
-                        setvar2("HOSTNAME", uts.nodename);
+                        setvar0("HOSTNAME", uts.nodename);
                 }
 #endif
                 p = lookupvar("PWD");
@@ -13309,7 +13328,7 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
                                 hp = lookupvar("HOME");
                                 if (hp) {
                                         hp = concat_path_file(hp, ".ash_history");
-                                        setvar2("HISTFILE", hp);
+                                        setvar0("HISTFILE", hp);
                                         free((char*)hp);
                                         hp = lookupvar("HISTFILE");
                                 }
diff --git a/shell/ash_test/ash-heredoc/heredoc1.right b/shell/ash_test/ash-heredoc/heredoc1.right
index 895f5ee80..40aa5a5fe 100644
--- a/shell/ash_test/ash-heredoc/heredoc1.right
+++ b/shell/ash_test/ash-heredoc/heredoc1.right
@@ -1 +1 @@
-heredoc1.tests: line 3: syntax error: unexpected "then"
+./heredoc1.tests: line 3: syntax error: unexpected "then"
diff --git a/shell/ash_test/ash-vars/var3.right b/shell/ash_test/ash-vars/var3.right
new file mode 100644
index 000000000..8eb0e3337
--- /dev/null
+++ b/shell/ash_test/ash-vars/var3.right
@@ -0,0 +1,5 @@
+1
+1
+
+
+0
diff --git a/shell/ash_test/ash-vars/var3.tests b/shell/ash_test/ash-vars/var3.tests
new file mode 100755
index 000000000..97b102cbe
--- /dev/null
+++ b/shell/ash_test/ash-vars/var3.tests
@@ -0,0 +1 @@
+x=0; f() { local x=1; echo $x; local x; echo $x; unset x; echo $x; local x; echo $x; }; f; echo $x