sh: Try to execute programs in /bin if they are not found

apps/src/sh.c

@@ -1,3 +1,4 @@
+#include <errno.h>
 #include <luna.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -104,6 +105,17 @@ void command_execute(command* cmd)
     }
     if (child == 0)
     {
+        if (cmd->buffer[0] != '/' && access(cmd->buffer, F_OK) < 0) // FIXME: Race condition.
+        {
+            if (errno == ENOENT)
+            { // Try in /bin
+                char* buf = malloc(cmd->size + 6);
+                strlcpy(buf, "/bin/", 6);
+                strncat(buf, cmd->buffer, cmd->size);
+                execv(buf, NULL);
+            }
+        }
+        else
             execv(cmd->buffer, NULL);
         perror(cmd->buffer);
         exit(127);