CE implement running commands in background

ce/interp.c

@@ -370,7 +370,7 @@ static void cmd_write_proc (void* arg) {
   }
 }
 
-static void execute_cmd (struct ast_cmd* cmd, struct context* context) {
+static void execute_cmd (struct ast_cmd* cmd, struct context* context, bool run_bg) {
   if (strcmp (cmd->name, "echo") == 0) {
     echo (context, cmd->args, cmd->arg_count);
   } else if (strcmp (cmd->name, "help") == 0) {
@@ -444,18 +444,25 @@ static void execute_cmd (struct ast_cmd* cmd, struct context* context) {
       i++;
     }
 
-    struct cmd_write_proc_ctx wpctx = {.pgid = pgid, .cancel_pid = pid};
+    if (run_bg) {
+      exec_partial_fini (pid);
 
-    struct process_data* write_pdata = process_spawn (&cmd_write_proc, (void*)&wpctx);
-    struct process_data* collect_pdata = process_spawn (&cmd_collect_proc, (void*)(uintptr_t)pgid);
+      cprintf (context, "started background process: PID %d\n", pid);
+    } else {
+      struct cmd_write_proc_ctx wpctx = {.pgid = pgid, .cancel_pid = pid};
 
-    exec_partial_fini (pid);
-    wait_for_pid (pid);
+      struct process_data* write_pdata = process_spawn (&cmd_write_proc, (void*)&wpctx);
+      struct process_data* collect_pdata =
+          process_spawn (&cmd_collect_proc, (void*)(uintptr_t)pgid);
 
-    kill (write_pdata->pid);
-    process_data_free (write_pdata);
-    kill (collect_pdata->pid);
-    process_data_free (collect_pdata);
+      exec_partial_fini (pid);
+      wait_for_pid (pid);
+
+      kill (write_pdata->pid);
+      process_data_free (write_pdata);
+      kill (collect_pdata->pid);
+      process_data_free (collect_pdata);
+    }
   }
 }
 
@@ -507,24 +514,27 @@ static void execute_redir (struct ast_redir* redir, struct context* context) {
   filewriter_fini (&fw);
 }
 
-void execute (struct ast_node* root, struct context* context) {
+void execute (struct ast_node* root, struct context* context, bool run_bg) {
   struct context subcontext;
   memset (&subcontext, 0, sizeof (subcontext));
 
   switch (root->class) {
   case AST_NODE_CLASS_CMD:
-    execute_cmd (&root->u.cmd, context);
+    execute_cmd (&root->u.cmd, context, run_bg);
     break;
   case AST_NODE_CLASS_SUBSHELL:
-    execute (root->u.subshell.inner, &subcontext);
+    execute (root->u.subshell.inner, &subcontext, run_bg);
     break;
   case AST_NODE_CLASS_SEQ:
-    execute (root->u.seq.left, context);
-    execute (root->u.seq.right, context);
+    execute (root->u.seq.left, context, run_bg);
+    execute (root->u.seq.right, context, run_bg);
     break;
   case AST_NODE_CLASS_REDIR:
-    execute (root->u.redir.source, &subcontext);
+    execute (root->u.redir.source, &subcontext, run_bg);
     execute_redir (&root->u.redir, &subcontext);
     break;
+  case AST_NODE_CLASS_RUN_BG:
+    execute (root->u.run_bg.expr, context, true);
+    break;
   }
 }

ce/interp.h

@@ -5,7 +5,7 @@
 #include "parser.h"
 #include <stdbool.h>
 
-void execute (struct ast_node* root, struct context* context);
+void execute (struct ast_node* root, struct context* context, bool run_bg);
 
 bool interp_is_running (void);
 

ce/parser.c

@@ -13,6 +13,7 @@ static struct parse_rule parse_rules[] = {
     [TOKEN_CLASS_CPAREN] = {NULL, NULL, PREC_NONE},
     [TOKEN_CLASS_SEMICOLON] = {NULL, &semicolon_led, PREC_SEQ},
     [TOKEN_CLASS_REDIR] = {NULL, &redir_led, PREC_REDIR},
+    [TOKEN_CLASS_AMPERSAND] = {NULL, &run_bg_led, PREC_RUN_BG},
 };
 
 static struct token* get_token (struct list_node_link* link) {
@@ -114,6 +115,16 @@ struct ast_node* redir_led (struct parser* parser, struct token* token, struct a
   return node;
 }
 
+struct ast_node* run_bg_led (struct parser* parser, struct token* token, struct ast_node* left) {
+  (void)token;
+
+  struct ast_node* node = arena_malloc (&arena, sizeof (*node));
+  node->class = AST_NODE_CLASS_RUN_BG;
+  node->u.run_bg.expr = left;
+
+  return node;
+}
+
 void tokenize (struct list_node_link** tokens, const char* text) {
   const char* p = text;
 
@@ -123,7 +134,7 @@ void tokenize (struct list_node_link** tokens, const char* text) {
       continue;
     }
 
-    if (*p == '(' || *p == ')' || *p == ';' || *p == '>') {
+    if (*p == '(' || *p == ')' || *p == ';' || *p == '>' || *p == '&') {
       struct token* token = arena_malloc (&arena, sizeof (*token));
       memset (token, 0, sizeof (*token));
 
@@ -136,6 +147,8 @@ void tokenize (struct list_node_link** tokens, const char* text) {
         token->class = TOKEN_CLASS_SEMICOLON;
       else if (*p == '>')
         token->class = TOKEN_CLASS_REDIR;
+      else if (*p == '&')
+        token->class = TOKEN_CLASS_AMPERSAND;
 
       list_append (*tokens, &token->tokens_link);
       p++;
@@ -174,7 +187,7 @@ void parse_and_execute (struct list_node_link* tokens) {
     if (root != NULL) {
       struct context context;
       memset (&context, 0, sizeof (context));
-      execute (root, &context);
+      execute (root, &context, false);
 
       if (context.strbuf.items != NULL)
         mprintf ("%.*s", (int)context.strbuf.count, context.strbuf.items);

ce/parser.h

@@ -11,6 +11,7 @@
 #define TOKEN_CLASS_WORD      2
 #define TOKEN_CLASS_SEMICOLON 3
 #define TOKEN_CLASS_REDIR     4
+#define TOKEN_CLASS_AMPERSAND 5
 
 struct token {
   struct list_node_link tokens_link;
@@ -22,11 +23,13 @@ struct token {
 #define PREC_LOWEST 1
 #define PREC_SEQ    2
 #define PREC_REDIR  3
+#define PREC_RUN_BG 4
 
 #define AST_NODE_CLASS_CMD      0
 #define AST_NODE_CLASS_SUBSHELL 1
 #define AST_NODE_CLASS_SEQ      2
 #define AST_NODE_CLASS_REDIR    3
+#define AST_NODE_CLASS_RUN_BG   4
 
 struct ast_node;
 
@@ -50,6 +53,10 @@ struct ast_redir {
   char* file_path;
 };
 
+struct ast_run_bg {
+  struct ast_node* expr;
+};
+
 struct ast_node {
   int class;
   union {
@@ -57,6 +64,7 @@ struct ast_node {
     struct ast_subshell subshell;
     struct ast_seq seq;
     struct ast_redir redir;
+    struct ast_run_bg run_bg;
   } u;
 };
 
@@ -85,6 +93,8 @@ struct ast_node* semicolon_led (struct parser* parser, struct token* token, stru
 
 struct ast_node* redir_led (struct parser* parser, struct token* token, struct ast_node* left);
 
+struct ast_node* run_bg_led (struct parser* parser, struct token* token, struct ast_node* left);
+
 void tokenize (struct list_node_link** tokens, const char* text);
 
 void parse_and_execute (struct list_node_link* tokens);