ash: handle "A=1 A=2 B=$A; echo $B". closes bug 947.

6 files changed, 96 insertions, 39 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 10eb90d30..4f9caa434 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -42,19 +42,18 @@
  * a quit signal will generate a core dump.
  */
 #define DEBUG 0
-#define IFS_BROKEN
 #define PROFILE 0
-#if ENABLE_ASH_JOB_CONTROL
-#define JOBS 1
-#else
-#define JOBS 0
-#endif
+
+#define IFS_BROKEN
+
+#define JOBS ENABLE_ASH_JOB_CONTROL
 
 #if DEBUG
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE
 #endif
 #endif
+
 #include "busybox.h" /* for applet_names */
 #include <paths.h>
 #include <setjmp.h>
@@ -5501,15 +5500,19 @@ expari(int quotes)
 #endif
 
 /* argstr needs it */
-static char *evalvar(char *p, int flag);
+static char *evalvar(char *p, int flag, struct strlist *var_str_list);
 
 /*
  * Perform variable and command substitution.  If EXP_FULL is set, output CTLESC
  * characters to allow for further processing.  Otherwise treat
  * $@ like $* since no splitting will be performed.
+ *
+ * var_str_list (can be NULL) is a list of "VAR=val" strings which take precedence
+ * over shell varables. Needed for "A=a B=$A; echo $B" case - we use it
+ * for correct expansion of "B=$A" word.
  */
 static void
-argstr(char *p, int flag)
+argstr(char *p, int flag, struct strlist *var_str_list)
 {
         static const char spclchars[] ALIGN1 = {
                 '=',
@@ -5611,7 +5614,7 @@ argstr(char *p, int flag)
                                         p[5] == CTLQUOTEMARK
                                 ))
                         ) {
-                                p = evalvar(p + 1, flag) + 1;
+                                p = evalvar(p + 1, flag, /* var_str_list: */ NULL) + 1;
                                 goto start;
                         }
                         inquotes = !inquotes;
@@ -5627,7 +5630,7 @@ argstr(char *p, int flag)
                         length++;
                         goto addquote;
                 case CTLVAR:
-                        p = evalvar(p, flag);
+                        p = evalvar(p, flag, var_str_list);
                         goto start;
                 case CTLBACKQ:
                         c = 0;
@@ -5731,7 +5734,8 @@ varunset(const char *end, const char *var, const char *umsg, int varflags)
 }
 
 static const char *
-subevalvar(char *p, char *str, int strloc, int subtype, int startloc, int varflags, int quotes)
+subevalvar(char *p, char *str, int strloc, int subtype,
+                int startloc, int varflags, int quotes, struct strlist *var_str_list)
 {
         char *startp;
         char *loc;
@@ -5743,7 +5747,8 @@ subevalvar(char *p, char *str, int strloc, int subtype, int startloc, int varfla
         char *(*scan)(char *, char *, char *, char *, int , int);
 
         herefd = -1;
-        argstr(p, subtype != VSASSIGN && subtype != VSQUESTION ? EXP_CASE : 0);
+        argstr(p, (subtype != VSASSIGN && subtype != VSQUESTION) ? EXP_CASE : 0,
+                        var_str_list);
         STPUTC('\0', expdest);
         herefd = saveherefd;
         argbackq = saveargbackq;
@@ -5802,7 +5807,7 @@ subevalvar(char *p, char *str, int strloc, int subtype, int startloc, int varfla
  * Add the value of a specialized variable to the stack string.
  */
 static ssize_t
-varvalue(char *name, int varflags, int flags)
+varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
 {
         int num;
         char *p;
@@ -5899,6 +5904,30 @@ varvalue(char *name, int varflags, int flags)
                 p = num ? shellparam.p[num - 1] : arg0;
                 goto value;
         default:
+                /* NB: name has form "VAR=..." */
+
+                /* "A=a B=$A" case: var_str_list is a list of "A=a" strings
+                 * which should be considered before we check variables. */
+                if (var_str_list) {
+                        unsigned name_len = (strchrnul(name, '=') - name) + 1;
+                        p = NULL;
+                        do {
+                                char *str = var_str_list->text;
+                                char *eq = strchr(str, '=');
+                                if (!eq) /* stop at first non-assignment */
+                                        break;
+                                eq++;
+                                if (name_len == (eq - str)
+                                 && strncmp(str, name, name_len) == 0) {
+                                        p = eq;
+                                        /* goto value; - WRONG! */
+                                        /* think "A=1 A=2 B=$A" */
+                                }
+                                var_str_list = var_str_list->next;
+                        } while (var_str_list);
+                        if (p)
+                                goto value;
+                }
                 p = lookupvar(name);
  value:
                 if (!p)
@@ -5920,20 +5949,17 @@ varvalue(char *name, int varflags, int flags)
  * input string.
  */
 static char *
-evalvar(char *p, int flag)
+evalvar(char *p, int flag, struct strlist *var_str_list)
 {
-        int subtype;
-        int varflags;
+        char varflags;
+        char subtype;
+        char quoted;
+        char easy;
         char *var;
         int patloc;
-        int c;
         int startloc;
         ssize_t varlen;
-        int easy;
-        int quotes;
-        int quoted;
 
-        quotes = flag & (EXP_FULL | EXP_CASE);
         varflags = *p++;
         subtype = varflags & VSTYPE;
         quoted = varflags & VSQUOTE;
@@ -5943,7 +5969,7 @@ evalvar(char *p, int flag)
         p = strchr(p, '=') + 1;
 
  again:
-        varlen = varvalue(var, varflags, flag);
+        varlen = varvalue(var, varflags, flag, var_str_list);
         if (varflags & VSNUL)
                 varlen--;
 
@@ -5957,7 +5983,8 @@ evalvar(char *p, int flag)
                 if (varlen < 0) {
                         argstr(
                                 p, flag | EXP_TILDE |
-                                        (quoted ?  EXP_QWORD : EXP_WORD)
+                                        (quoted ?  EXP_QWORD : EXP_WORD),
+                                var_str_list
                         );
                         goto end;
                 }
@@ -5968,7 +5995,11 @@ evalvar(char *p, int flag)
 
         if (subtype == VSASSIGN || subtype == VSQUESTION) {
                 if (varlen < 0) {
-                        if (subevalvar(p, var, 0, subtype, startloc, varflags, 0)) {
+                        if (subevalvar(p, var, /* strloc: */ 0,
+                                        subtype, startloc, varflags,
+                                        /* quotes: */ 0,
+                                        var_str_list)
+                        ) {
                                 varflags &= ~VSNUL;
                                 /*
                                  * Remove any recorded regions beyond
@@ -5993,10 +6024,8 @@ evalvar(char *p, int flag)
         }
 
         if (subtype == VSNORMAL) {
-                if (!easy)
-                        goto end;
- record:
-                recordregion(startloc, expdest - (char *)stackblock(), quoted);
+                if (easy)
+                        goto record;
                 goto end;
         }
 
@@ -6019,8 +6048,11 @@ evalvar(char *p, int flag)
                  */
                 STPUTC('\0', expdest);
                 patloc = expdest - (char *)stackblock();
-                if (subevalvar(p, NULL, patloc, subtype,
-                                startloc, varflags, quotes) == 0) {
+                if (0 == subevalvar(p, /* str: */ NULL, patloc, subtype,
+                                startloc, varflags,
+                                /* quotes: */ flag & (EXP_FULL | EXP_CASE),
+                                var_str_list)
+                ) {
                         int amount = expdest - (
                                 (char *)stackblock() + patloc - 1
                         );
@@ -6028,14 +6060,15 @@ evalvar(char *p, int flag)
                 }
                 /* Remove any recorded regions beyond start of variable */
                 removerecordregions(startloc);
-                goto record;
+ record:
+                recordregion(startloc, expdest - (char *)stackblock(), quoted);
         }
 
  end:
         if (subtype != VSNORMAL) {      /* skip to end of alternative */
                 int nesting = 1;
                 for (;;) {
-                        c = *p++;
+                        char c = *p++;
                         if (c == CTLESC)
                                 p++;
                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
@@ -6420,7 +6453,8 @@ expandarg(union node *arg, struct arglist *arglist, int flag)
         STARTSTACKSTR(expdest);
         ifsfirst.next = NULL;
         ifslastp = NULL;
-        argstr(arg->narg.text, flag);
+        argstr(arg->narg.text, flag,
+                        /* var_str_list: */ arglist ? arglist->list : NULL);
         p = _STPUTC('\0', expdest);
         expdest = p - 1;
         if (arglist == NULL) {
@@ -6486,7 +6520,8 @@ casematch(union node *pattern, char *val)
         argbackq = pattern->narg.backquote;
         STARTSTACKSTR(expdest);
         ifslastp = NULL;
-        argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
+        argstr(pattern->narg.text, EXP_TILDE | EXP_CASE,
+                        /* var_str_list: */ NULL);
         STACKSTRNUL(expdest);
         result = patmatch(stackblock(), val);
         popstackmark(&smark);
@@ -8249,8 +8284,8 @@ bltincmd(int argc, char **argv)
 static void
 evalcommand(union node *cmd, int flags)
 {
-        static const struct builtincmd bltin = {
-                "\0\0", bltincmd
+        static const struct builtincmd null_bltin = {
+                "\0\0", bltincmd /* why three NULs? */
         };
         struct stackmark smark;
         union node *argp;
@@ -8276,7 +8311,7 @@ evalcommand(union node *cmd, int flags)
         back_exitstatus = 0;
 
         cmdentry.cmdtype = CMDBUILTIN;
-        cmdentry.u.cmd = &bltin;
+        cmdentry.u.cmd = &null_bltin;
         varlist.lastp = &varlist.list;
         *varlist.lastp = NULL;
         arglist.lastp = &arglist.list;
@@ -8352,7 +8387,7 @@ evalcommand(union node *cmd, int flags)
                         }
                         sp = arglist.list;
                 }
-                full_write(preverrout_fd, "\n", 1);
+                safe_write(preverrout_fd, "\n", 1);
         }
 
         cmd_is_exec = 0;
diff --git a/shell/ash_test/ash-vars/var1.right b/shell/ash_test/ash-vars/var1.right
new file mode 100644
index 000000000..2a01291bb
--- /dev/null
+++ b/shell/ash_test/ash-vars/var1.right
@@ -0,0 +1,6 @@
+a=a A=a
+a=a A=a
+a= A=
+a= A=
+a=a A=a
+a=a A=a
diff --git a/shell/ash_test/ash-vars/var1.tests b/shell/ash_test/ash-vars/var1.tests
new file mode 100755
index 000000000..802e489bd
--- /dev/null
+++ b/shell/ash_test/ash-vars/var1.tests
@@ -0,0 +1,14 @@
+# check that first assignment has proper effect on second one
+
+(
+a=a A=$a
+echo a=$a A=$A
+)
+(a=a A=$a; echo a=$a A=$A)
+(a=a A=$a echo a=$a A=$A)
+(a=a A=$a /bin/echo a=$a A=$A)
+
+f() { echo a=$a A=$A; }
+
+(a=a A=$a f)
+(a=a A=$a; f)
diff --git a/shell/ash_test/ash-vars/var2.right b/shell/ash_test/ash-vars/var2.right
new file mode 100644
index 000000000..8fed138eb
--- /dev/null
+++ b/shell/ash_test/ash-vars/var2.right
@@ -0,0 +1 @@
+bus/usb/1/2
diff --git a/shell/ash_test/ash-vars/var2.tests b/shell/ash_test/ash-vars/var2.tests
new file mode 100755
index 000000000..07feaeb8b
--- /dev/null
+++ b/shell/ash_test/ash-vars/var2.tests
@@ -0,0 +1 @@
+X=usbdev1.2 X=${X#usbdev} B=${X%%.*} D=${X#*.}; echo bus/usb/$B/$D
diff --git a/shell/ash_test/run-all b/shell/ash_test/run-all
index 416900aa2..e02333888 100755
--- a/shell/ash_test/run-all
+++ b/shell/ash_test/run-all
@@ -17,6 +17,7 @@ export THIS_SH
 do_test()
 {
     test -d "$1" || return 0
+    echo do_test "$1"
     (
     cd "$1" || { echo "cannot cd $1!"; exit 1; }
     for x in run-*; do
@@ -53,7 +54,6 @@ if [ $# -lt 1 ]; then
     modules=`ls -d ash-*`
 
     for module in $modules; do
-        echo do_test $module
         do_test $module
     done
 else