which,ash: code shrink detection of standalone shell

Commit 6d87be4d7 (which,ash: changes to which/command/type) let
'which' detect when it's run from a standalone shell by having
the shell pass the undocumented '-s' option.

A better solution is to alter argv[0] when 'which' is run from a
standalone shell.  This is possible because the code path through
run_noexec_applet_and_exit() and which_main() doesn't actually
use argv[0].

- No special treatment is required in ash when 'which' has no
  arguments or the '--help' option.

- tryexec() no longer needs an extra element before the start of
  argv.  The commit 027fb22e2 can be reverted and the allocation
  of argv in evalcommand() simplified.

- 'which' no longer needs to handle the '-s' option.

Saves 96-104 bytes.

1 files changed, 9 insertions, 13 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 94aabbc4c..aa291b99d 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9104,14 +9104,9 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) const char *cmd, char **argv, c
                         /* mingw-w64's getopt() uses __argv[0] as the program name */
                         __argv[0] = (char *)cmd;
                         /* 'which' wants to know if it was invoked from a standalone
-                         * shell.  Use the spare element of argv to add a flag, but
-                         * not if the first argument is '--help', that's a special
-                         * case. */
-                        if (strcmp(argv[0], "which") == 0 &&
-                                        (argv[1] == NULL || strcmp(argv[1], "--help") != 0)) {
-                                --argv;
-                                argv[0] = argv[1];
-                                argv[1] = (char *)"-s";
+                         * shell.  'Which' in argv[0] indicates this. */
+                        if (strcmp(argv[0], "which") == 0) {
+                                argv[0] = (char *)"Which";
                         }
 # else
                 if (APPLET_IS_NOEXEC(applet_no)) {
@@ -11585,9 +11580,13 @@ evalcommand(union node *cmd, int flags)
 
         localvar_stop = pushlocalvars(vlocal);
 
+#if ENABLE_PLATFORM_MINGW32
+        argv = nargv = stalloc(sizeof(char *) * (argc + 1));
+#else
         /* Reserve one extra spot at the front for shellexec. */
         nargv = stalloc(sizeof(char *) * (argc + 2));
         argv = ++nargv;
+#endif
         for (sp = arglist.list; sp; sp = sp->next) {
                 TRACE(("evalcommand arg: %s\n", sp->text));
                 *nargv++ = sp->text;
@@ -16791,8 +16790,7 @@ argv_size(struct datasize ds, char **p)
                         ds.funcstringsize += align_len(*p);
                         p++;
                 }
-                // Allow for argv[-1] used by tryexec().
-                ds.funcblocksize += 2 * sizeof(char *);
+                ds.funcblocksize += sizeof(char *);
         }
         return ds;
 }
@@ -16806,8 +16804,6 @@ argv_copy(char **p)
 #endif
 
         if (p) {
-                // argv[-1] for tryexec()
-                funcblock = (char *) funcblock + sizeof(char *);
                 while (*p) {
                         new = funcblock;
                         funcblock = (char *) funcblock + sizeof(char *);
@@ -16818,7 +16814,7 @@ argv_copy(char **p)
                 new = funcblock;
                 funcblock = (char *) funcblock + sizeof(char *);
                 *new = NULL;
-                return start + 1;
+                return start;
         }
         return NULL;
 }