allow chaining commands with '&&'

src/lexer/lexer.c

@@ -41,9 +41,7 @@ void msh_lexer_parse(msh_lexer *lexer, char *buf, SIZE_TYPE sz) {
   int i = 0, n = 0, j = 0;
   char cur_word_buf[1024];
 
-  /*case '#':
+  /*
-    do_clear = 1;
-    break;
   case '|':
     if (i + 1 < sz) {
       if (buf[i + 1] == '|') {
@@ -56,18 +54,6 @@ void msh_lexer_parse(msh_lexer *lexer, char *buf, SIZE_TYPE sz) {
     }
     do_clear = 1;
     break;
-  case '&':
-    if (i + 1 < sz) {
-      if (buf[i + 1] == '&') {
-        msh_lexer_push_item(lexer, MSH_LEXER_ITEM_TYPE_OP_AND, buf, 2);
-        last = i + 2;
-      } else {
-        msh_lexer_push_item(lexer, MSH_LEXER_ITEM_TYPE_OP_CONTROL, buf, 1);
-        last = i + 1;
-      }
-    }
-    do_clear = 1;
-    break;
   case ';':
     msh_lexer_push_item(lexer, MSH_LEXER_ITEM_TYPE_OP_SEMICOLON, buf, 1);
     do_clear = 1;
@@ -94,11 +80,22 @@ void msh_lexer_parse(msh_lexer *lexer, char *buf, SIZE_TYPE sz) {
         quote_mode = !quote_mode;
       }
       break;
+    case '&':
+      if (i + 1 < sz) {
+        if (buf[i + 1] == '&') {
+          msh_lexer_push_item(lexer, MSH_LEXER_ITEM_TYPE_OP_AND, buf, 2);
+          i++;
+        } else {
+          msh_lexer_push_item(lexer, MSH_LEXER_ITEM_TYPE_OP_CONTROL, buf, 1);
+        }
+      }
+      break;
     case ' ':
       if (quote_mode == 1) {
         goto do_add;
         break;
       }
+      /* fallthrough */
     case '\n':
     case '\0':
       cur_word_buf[n++] = '\0';
@@ -122,25 +119,13 @@ lexer_cancel:
   return;
 }
 
-int msh_lexer_execute(msh_lexer *lexer) {
+static int do_exec(msh_lexer *lexer, char *cmd, char **args, int *n,
-  msh_lexer_item_list *list = lexer->item_list_head;
+                   int *exec_status) {
-  char *cmd = list->item->str;
-  SIZE_TYPE cmd_size = list->item->strlen;
-
-  SIZE_TYPE args_size = 0;
-  char is_first_arg = 0, exec_success = 0, exec_status = 0;
-  unsigned short i = 0, n = 0, j = 0, counter = 0;
   char full_path[PATH_MAX];
-  char *args[512];
+  char is_first_arg = 0, exec_success = 0;
+  unsigned short i = 0, j = 0, counter = 0;
 
-  while (list != 0) {
+  args[*n] = 0;
-    if (!list->item) {
-      break;
-    }
-    args[n++] = list->item->str;
-    list = list->next;
-  }
-  args[n++] = 0;
 
   /* Do nothing on blank commands */
   if (*cmd == '\0') {
@@ -162,19 +147,20 @@ int msh_lexer_execute(msh_lexer *lexer) {
   } else {
     /* loop through all the path entries and check if the file exists in them.
      */
-    i = 0, n = 0, j = 0;
+    i = 0, *n = 0, j = 0;
     while (1) {
-      full_path[n++] = lexer->path[j];
+      full_path[*n] = lexer->path[j];
+      *n += 1;
       if (lexer->path[j] == '\0') {
-        full_path[n - 1] = msh_path_seperator;
+        full_path[*n - 1] = msh_path_seperator;
         for (i = 0; cmd[i] != 0; i++) {
-          full_path[i + n] = cmd[i];
+          full_path[i + *n] = cmd[i];
         }
-        n += i;
+        *n += i;
-        full_path[n++] = '\0';
+        full_path[*n++] = '\0';
 
         if (msh_path_exists(full_path)) {
-          exec_status = msh_execute(full_path, args);
+          msh_execute(full_path, args);
           exec_success = 1;
           break;
         }
@@ -183,7 +169,7 @@ int msh_lexer_execute(msh_lexer *lexer) {
         if (counter > 2) {
           break;
         }
-        n = 0;
+        *n = 0;
       } else {
         counter = 0;
       }
@@ -193,10 +179,62 @@ int msh_lexer_execute(msh_lexer *lexer) {
   if (!exec_success) {
     msh_print_strings("msh: ", cmd, ": command not found\n\r", 0);
   }
+  /* flush out args */
+  for (i = 0; i < 512; i++) {
+    if (args[i] == 0) {
+      break;
+    }
+    args[i] = 0;
+  }
+
+  return 0;
+}
+
+int msh_lexer_execute(msh_lexer *lexer) {
+  msh_lexer_item_list *list = lexer->item_list_head;
+  char *cmd = list->item->str;
+  SIZE_TYPE cmd_size;
+  int i = 0, n = 0, exec_status = 0;
+  SIZE_TYPE args_size = 0;
+  char *args[512];
+
+  while (list != 0) {
+    if (!list->item) {
+      break;
+    }
+    switch (list->item->type) {
+    case MSH_LEXER_ITEM_TYPE_UNKNOWN:
+      break;
+    case MSH_LEXER_ITEM_TYPE_WORD:
+      if (cmd == 0 && *list->item->str != '\0') {
+        cmd = list->item->str;
+      } else {
+        args[n++] = list->item->str;
+      }
+      break;
+    case MSH_LEXER_ITEM_TYPE_COMMENT:
+      break;
+    case MSH_LEXER_ITEM_TYPE_OP_OR:
+      break;
+    case MSH_LEXER_ITEM_TYPE_OP_AND:
+      do_exec(lexer, cmd, args, &n, &exec_status);
+      n = 0;
+      cmd = 0;
+      break;
+    case MSH_LEXER_ITEM_TYPE_OP_PIPE:
+      break;
+    case MSH_LEXER_ITEM_TYPE_OP_CONTROL:
+      break;
+    case MSH_LEXER_ITEM_TYPE_OP_SEMICOLON:
+      break;
+    }
+    list = list->next;
+  }
+  do_exec(lexer, cmd, args, &n, &exec_status);
 
   msh_lexer_flush(lexer);
 
-  return exec_status == 0 ? exec_status : exec_success;
+  return 0;
 };
 
 void msh_lexer_flush(msh_lexer *lexer) {

src/system/system.h

@@ -95,12 +95,23 @@ const char *msh_working_directory();
  */
 void msh_set_working_directory(const char *);
 
+/*
+ * Type representing an OS's process.
+ * !! Do NOT use the fields directly, use the appropriate macros instead.
+ */
+typedef struct msh_process_t {
+#ifdef __linux__
+  SIZE_TYPE __pid;
+#endif
+} msh_process;
+
 /*
  * Execute given command with args.
  *
  * cmd is self explanatory, args is a null terminated array of strings based on
  * the arguments the user provided.
  *
+ * Returns the process to be waited on.
  *
  * Non-zero return values are the exit status. -1 implies the command was not
  * found.