implemented background process operator

1 files changed, 144 insertions, 0 deletions

diff --git a/src/builtins.c b/src/builtins.c
new file mode 100644
index 0000000..5b032c1
--- /dev/null
+++ b/src/builtins.c
@@ -0,0 +1,144 @@
+/*
+Copyright (c) 2024, Lance Borden
+All rights reserved.
+
+This software is licensed under the BSD 3-Clause License.
+You may obtain a copy of the license at:
+https://opensource.org/licenses/BSD-3-Clause
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted under the conditions stated in the BSD 3-Clause
+License.
+
+THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTIES,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+*/
+
+#include "help.h"
+#include "lua.h"
+#include "lua_api.h"
+#include "lush.h"
+#include <asm-generic/ioctls.h>
+#include <bits/time.h>
+#include <dirent.h>
+#include <linux/limits.h>
+#include <locale.h>
+#include <pwd.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <termios.h>
+#include <time.h>
+#include <unistd.h>
+
+char *builtin_strs[] = {"cd", "help", "exit", "time"};
+char *builtin_usage[] = {"[dirname]", "", "", "[pipeline]"};
+
+int (*builtin_func[])(lua_State *, char ***) = {
+	&lush_cd, &lush_help, &lush_exit, &lush_time, &lush_lua};
+
+int lush_num_builtins() { return sizeof(builtin_strs) / sizeof(char *); }
+
+int lush_cd(lua_State *L, char ***args) {
+	uid_t uid = getuid();
+	struct passwd *pw = getpwuid(uid);
+	if (!pw) {
+		perror("retrieve home dir");
+		return 0;
+	}
+	if (args[0][1] == NULL) {
+		if (chdir(pw->pw_dir) != 0) {
+			perror("lush: cd");
+		}
+	} else {
+		char path[PATH_MAX];
+		char extended_path[PATH_MAX];
+		char *tilda = strchr(args[0][1], '~');
+		// first check if they want to go to old dir
+		if (strcmp("-", args[0][1]) == 0) {
+			strcpy(path, getenv("OLDPWD"));
+		} else if (tilda) {
+			strcpy(path, pw->pw_dir);
+			strcat(path, tilda + 1);
+		} else {
+			strcpy(path, args[0][1]);
+		}
+
+		char *exp_path = realpath(path, extended_path);
+		if (!exp_path) {
+			perror("realpath");
+			return 1;
+		}
+
+		char *cwd = getcwd(NULL, 0);
+		setenv("OLDPWD", cwd, 1);
+		free(cwd);
+
+		if (chdir(exp_path) != 0) {
+			perror("lush: cd");
+		}
+	}
+
+	return 1;
+}
+
+int lush_help(lua_State *L, char ***args) {
+	printf("%s\n", lush_get_help_text());
+#ifdef LUSH_VERSION
+	printf("Lunar Shell, version %s\n", LUSH_VERSION);
+#endif
+	printf("These shell commands are defined internally. Type 'help' at any "
+		   "time to reference this list.\n");
+	printf("Available commands: \n");
+	for (int i = 0; i < lush_num_builtins(); i++) {
+		printf("- %s %s\n", builtin_strs[i], builtin_usage[i]);
+	}
+	return 1;
+}
+
+int lush_exit(lua_State *L, char ***args) { exit(0); }
+
+int lush_time(lua_State *L, char ***args) {
+	// advance past time command
+	args[0]++;
+
+	// count commands
+	int i = 0;
+	while (args[i++]) {
+		;
+	}
+
+	// get time
+	struct timespec start, end;
+	double elapsed_time;
+
+	clock_gettime(CLOCK_MONOTONIC, &start);
+	int rc = lush_run(L, args, i);
+	clock_gettime(CLOCK_MONOTONIC, &end);
+
+	elapsed_time = (end.tv_sec - start.tv_sec) * 1000.0 +
+				   (end.tv_nsec - start.tv_nsec) / 1e6;
+	printf("Time: %.3f milliseconds\n", elapsed_time);
+
+	// return pointer back to "time" for free()
+	args[0]--;
+	return rc;
+}
+
+int lush_lua(lua_State *L, char ***args) {
+	// run the lua file given
+	const char *script = args[0][0];
+	// move args forward to any command line args
+	args[0]++;
+
+	lua_load_script(L, script, args[0]);
+
+	// return pointer back to lua file
+	args[0]--;
+	return 1;
+}