Changeset 2649 in kBuild for trunk/src

Timestamp:

Sep 9, 2012 3:47:26 AM (13 years ago)

Author:

bird

Message:

kash: detect shell invokations via /usr/bin/env in hash bang.

File:

• trunk/src/kash/exec.c (modified) (4 diffs)

trunk/src/kash/exec.c

@@ -228 +228 @@
 }
 
-
 #ifdef EXEC_HASH_BANG_SCRIPT
+
+/*
+ * Checks if NAME is the (base) name of the shell executable or something
+ * very similar.
+ */
+STATIC int
+is_shell_exe_name(const char *name)
+{
+    return equal(name, "kmk_ash")
+        || equal(name, "kmk_sh")
+        || equal(name, "kash")
+        || equal(name, "sh");
+}
+
 /*
  * Execute an interpreter introduced by "#!", for systems where this
@@ -277 +290 @@
         }
 
-        /* if no args, maybe shell and no exec is needed. */
-        if (ap == newargs + 1) {
+        /* Special optimizations / builtins. */
+        i = ap - newargs;
+        if (i > 1 && equal(newargs[0], "/usr/bin/env"))  {
+                /* /usr/bin/env <self> -> easy. */
+                if (i == 2 && is_shell_exe_name(newargs[1])) {
+                    TRACE((psh, "hash bang /usr/bin/env self\n"));
+                    return;
+                }
+                /** @todo implement simple /usr/bin/env that locates an exec in the PATH. */
+
+        } else if (i == 1) { /* if no args, maybe shell and no exec is needed. */
                 p = strrchr(newargs[0], '/');
                 if (!p)
                         p = newargs[0];
-                if (equal(p, "kmk_ash") || equal(p, "kmk_sh") || equal(p, "kash") || equal(p, "sh")) {
+                if (is_shell_exe_name(p)) {
                         TRACE((psh, "hash bang self\n"));
                         return;
@@ -288 +310 @@
         }
 
+        /* Combine the argument lists and exec. */
         i = (char *)ap - (char *)newargs;               /* size in bytes */
         if (i == 0)
@@ -297 +320 @@
                 *ap2++ = *ap++;
         ap = argv;
-        while (*ap2++ = *ap++);
+        while ((*ap2++ = *ap++))
+            /* nothing*/;
         TRACE((psh, "hash bang '%s'\n", new[0]));
         shellexec(psh, new, envp, pathval(psh), 0, 0);
         /* NOTREACHED */
 }
-#endif
-
+
+#endif /* EXEC_HASH_BANG_SCRIPT */