hush: fix set [--] params. Closes bug 199.

function                                             old     new   delta
builtin_set                                           55     194    +139
add_strings_to_strings                                 -     130    +130
add_string_to_strings                                110      26     -84
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/1 up/down: 269/-84)           Total: 185 bytes

1 files changed, 61 insertions, 9 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 3b87855b6..e6189f841 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -471,8 +471,9 @@ struct globals {
         smallint fake_mode;
         /* these three support $?, $#, and $1 */
         smalluint last_return_code;
+        smalluint global_args_malloced;
+        int global_argc; /* NB: $# + 1 */
         char **global_argv;
-        int global_argc;
 #if ENABLE_HUSH_LOOPS
         unsigned depth_break_continue;
         unsigned depth_of_loop;
@@ -646,7 +647,7 @@ static char *unbackslash(char *src)
         return dst;
 }
 
-static char **add_strings_to_strings(char **strings, char **add)
+static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
 {
         int i;
         unsigned count1;
@@ -671,7 +672,7 @@ static char **add_strings_to_strings(char **strings, char **add)
         v[count1 + count2] = NULL;
         i = count2;
         while (--i >= 0)
-                v[count1 + i] = add[i];
+                v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
         return v;
 }
 
@@ -680,7 +681,7 @@ static char **add_string_to_strings(char **strings, char *add)
         char *v[2];
         v[0] = add;
         v[1] = NULL;
-        return add_strings_to_strings(strings, v);
+        return add_strings_to_strings(strings, v, /*dup:*/ 0);
 }
 
 static void putenv_all(char **strings)
@@ -4644,17 +4645,68 @@ static int builtin_read(char **argv)
         return set_local_var(string, 0);
 }
 
-/* built-in 'set [VAR=value]' handler */
+/* built-in 'set' handler
+ * SUSv3 says:
+ * set [-abCefmnuvx] [-h] [-o option] [argument...]
+ * set [+abCefmnuvx] [+h] [+o option] [argument...]
+ * set -- [argument...]
+ * set -o
+ * set +o
+ * Implementations shall support the options in both their hyphen and
+ * plus-sign forms. These options can also be specified as options to sh.
+ * Examples:
+ * Write out all variables and their values: set
+ * Set $1, $2, and $3 and set "$#" to 3: set c a b
+ * Turn on the -x and -v options: set -xv
+ * Unset all positional parameters: set --
+ * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
+ * Set the positional parameters to the expansion of x, even if x expands
+ * with a leading '-' or '+': set -- $x
+ *
+ * So far, we only support "set -- [argument...]" by ignoring all options
+ * (also, "-o option" will be mishandled by taking "option" as parameter #1).
+ */
 static int builtin_set(char **argv)
 {
-        char *temp = argv[1];
         struct variable *e;
+        char **pp;
+        char *arg = *++argv;
 
-        if (temp == NULL)
+        if (arg == NULL) {
                 for (e = G.top_var; e; e = e->next)
                         puts(e->varstr);
-        else
-                set_local_var(xstrdup(temp), 0);
+        } else {
+                /* NB: G.global_argv[0] ($0) is never freed/changed */
+
+                if (G.global_args_malloced) {
+                        pp = G.global_argv;
+                        while (*++pp)
+                                free(*pp);
+                        G.global_argv[1] = NULL;
+                } else {
+                        G.global_args_malloced = 1;
+                        pp = xzalloc(sizeof(pp[0]) * 2);
+                        pp[0] = G.global_argv[0]; /* retain $0 */
+                        G.global_argv = pp;
+                }
+                do  {
+                        if (arg[0] == '+')
+                                continue;
+                        if (arg[0] != '-')
+                                break;
+                        if (arg[1] == '-' && arg[2] == '\0') {
+                                argv++;
+                                break;
+                        }
+                } while ((arg = *++argv) != NULL);
+                /* Now argv[0] is 1st argument */
+
+                /* This realloc's G.global_argv */
+                G.global_argv = pp = add_strings_to_strings(G.global_argv, argv, /*dup:*/ 1);
+                G.global_argc = 1;
+                while (*++pp)
+                        G.global_argc++;
+        }
 
         return EXIT_SUCCESS;
 }