shell, the gate of hell

alias_builtins.c

@@ -0,0 +1,152 @@
+#include "shell.h"
+
+int shellby_alias(char **args, char __attribute__((__unused__)) **front);
+void set_alias(char *var_name, char *value);
+void print_alias(alias_t *alias);
+
+/**
+ * shellby_alias - Builtin command that either prints all aliases, specific
+ * aliases, or sets an alias.
+ * @args: An array of arguments.
+ * @front: A double pointer to the beginning of args.
+ *
+ * Return: If an error occurs - -1.
+ *         Otherwise - 0.
+ */
+int shellby_alias(char **args, char __attribute__((__unused__)) **front)
+{
+	alias_t *temp = aliases;
+	int i, ret = 0;
+	char *value;
+
+	if (!args[0])
+	{
+		while (temp)
+		{
+			print_alias(temp);
+			temp = temp->next;
+		}
+		return (ret);
+	}
+	for (i = 0; args[i]; i++)
+	{
+		temp = aliases;
+		value = _strchr(args[i], '=');
+		if (!value)
+		{
+			while (temp)
+			{
+				if (_strcmp(args[i], temp->name) == 0)
+				{
+					print_alias(temp);
+					break;
+				}
+				temp = temp->next;
+			}
+			if (!temp)
+				ret = create_error(args + i, 1);
+		}
+		else
+			set_alias(args[i], value);
+	}
+	return (ret);
+}
+
+/**
+ * set_alias - Will either set an existing alias 'name' with a new value,
+ * 'value' or creates a new alias with 'name' and 'value'.
+ * @var_name: Name of the alias.
+ * @value: Value of the alias. First character is a '='.
+ */
+void set_alias(char *var_name, char *value)
+{
+	alias_t *temp = aliases;
+	int len, j, k;
+	char *new_value;
+
+	*value = '\0';
+	value++;
+	len = _strlen(value) - _strspn(value, "'\"");
+	new_value = malloc(sizeof(char) * (len + 1));
+	if (!new_value)
+		return;
+	for (j = 0, k = 0; value[j]; j++)
+	{
+		if (value[j] != '\'' && value[j] != '"')
+			new_value[k++] = value[j];
+	}
+	new_value[k] = '\0';
+	while (temp)
+	{
+		if (_strcmp(var_name, temp->name) == 0)
+		{
+			free(temp->value);
+			temp->value = new_value;
+			break;
+		}
+		temp = temp->next;
+	}
+	if (!temp)
+		add_alias_end(&aliases, var_name, new_value);
+}
+
+/**
+ * print_alias - Prints the alias in the format name='value'.
+ * @alias: Pointer to an alias.
+ */
+void print_alias(alias_t *alias)
+{
+	char *alias_string;
+	int len = _strlen(alias->name) + _strlen(alias->value) + 4;
+
+	alias_string = malloc(sizeof(char) * (len + 1));
+	if (!alias_string)
+		return;
+	_strcpy(alias_string, alias->name);
+	_strcat(alias_string, "='");
+	_strcat(alias_string, alias->value);
+	_strcat(alias_string, "'\n");
+
+	write(STDOUT_FILENO, alias_string, len);
+	free(alias_string);
+}
+/**
+ * replace_aliases - Goes through the arguments and replace any matching alias
+ * with their value.
+ * @args: 2D pointer to the arguments.
+ *
+ * Return: 2D pointer to the arguments.
+ */
+char **replace_aliases(char **args)
+{
+	alias_t *temp;
+	int i;
+	char *new_value;
+
+	if (_strcmp(args[0], "alias") == 0)
+		return (args);
+	for (i = 0; args[i]; i++)
+	{
+		temp = aliases;
+		while (temp)
+		{
+			if (_strcmp(args[i], temp->name) == 0)
+			{
+				new_value = malloc(sizeof(char) * (_strlen(temp->value) + 1));
+				if (!new_value)
+				{
+					free_args(args, args);
+					return (NULL);
+				}
+				_strcpy(new_value, temp->value);
+				free(args[i]);
+				args[i] = new_value;
+				i--;
+				break;
+			}
+			temp = temp->next;
+		}
+	}
+
+	return (args);
+}

builtin.c

@@ -0,0 +1,192 @@
+#include "shell.h"
+int (*get_builtin(char *command))(char **args, char **front);
+int shellby_exit(char **args, char **front);
+int shellby_cd(char **args, char __attribute__((__unused__)) **front);
+int shellby_help(char **args, char __attribute__((__unused__)) **front);
+
+/**
+ * get_builtin - Matches a command with a corresponding
+ *               shellby builtin function.
+ * @command: The command to match.
+ *
+ * Return: A function pointer to the corresponding builtin.
+ */
+int (*get_builtin(char *command))(char **args, char **front)
+{
+	builtin_t funcs[] = {
+		{ "exit", shellby_exit },
+		{ "env", shellby_env },
+		{ "setenv", shellby_setenv },
+		{ "unsetenv", shellby_unsetenv },
+		{ "cd", shellby_cd },
+		{ "alias", shellby_alias },
+		{ "help", shellby_help },
+		{ NULL, NULL }
+	};
+	int i;
+
+	for (i = 0; funcs[i].name; i++)
+	{
+		if (_strcmp(funcs[i].name, command) == 0)
+			break;
+	}
+	return (funcs[i].f);
+}
+
+/**
+ * shellby_exit - Causes normal process termination
+ *                for the shellby shell.
+ * @args: An array of arguments containing the exit value.
+ * @front: A double pointer to the beginning of args.
+ *
+ * Return: If there are no arguments - -3.
+ *         If the given exit value is invalid - 2.
+ *         O/w - exits with the given status value.
+ *
+ * Description: Upon returning -3, the program exits back in the main function.
+ */
+int shellby_exit(char **args, char **front)
+{
+	int i, len_of_int = 10;
+	unsigned int num = 0, max = 1 << (sizeof(int) * 8 - 1);
+
+	if (args[0])
+	{
+		if (args[0][0] == '+')
+		{
+			i = 1;
+			len_of_int++;
+		}
+		for (; args[0][i]; i++)
+		{
+			if (i <= len_of_int && args[0][i] >= '0' && args[0][i] <= '9')
+				num = (num * 10) + (args[0][i] - '0');
+			else
+				return (create_error(--args, 2));
+		}
+	}
+	else
+	{
+		return (-3);
+	}
+	if (num > max - 1)
+		return (create_error(--args, 2));
+	args -= 1;
+	free_args(args, front);
+	free_env();
+	free_alias_list(aliases);
+	exit(num);
+}
+
+/**
+ * shellby_cd - Changes the current directory of the shellby process.
+ * @args: An array of arguments.
+ * @front: A double pointer to the beginning of args.
+ *
+ * Return: If the given string is not a directory - 2.
+ *         If an error occurs - -1.
+ *         Otherwise - 0.
+ */
+int shellby_cd(char **args, char __attribute__((__unused__)) **front)
+{
+	char **dir_info, *new_line = "\n";
+	char *oldpwd = NULL, *pwd = NULL;
+	struct stat dir;
+
+	oldpwd = getcwd(oldpwd, 0);
+	if (!oldpwd)
+		return (-1);
+
+	if (args[0])
+	{
+		if (*(args[0]) == '-' || _strcmp(args[0], "--") == 0)
+		{
+			if ((args[0][1] == '-' && args[0][2] == '\0') ||
+					args[0][1] == '\0')
+			{
+				if (_getenv("OLDPWD") != NULL)
+					(chdir(*_getenv("OLDPWD") + 7));
+			}
+			else
+			{
+				free(oldpwd);
+				return (create_error(args, 2));
+			}
+		}
+		else
+		{
+			if (stat(args[0], &dir) == 0 && S_ISDIR(dir.st_mode)
+					&& ((dir.st_mode & S_IXUSR) != 0))
+				chdir(args[0]);
+			else
+			{
+				free(oldpwd);
+				return (create_error(args, 2));
+			}
+		}
+	}
+	else
+	{
+		if (_getenv("HOME") != NULL)
+			chdir(*(_getenv("HOME")) + 5);
+	}
+
+	pwd = getcwd(pwd, 0);
+	if (!pwd)
+		return (-1);
+
+	dir_info = malloc(sizeof(char *) * 2);
+	if (!dir_info)
+		return (-1);
+
+	dir_info[0] = "OLDPWD";
+	dir_info[1] = oldpwd;
+	if (shellby_setenv(dir_info, dir_info) == -1)
+		return (-1);
+
+	dir_info[0] = "PWD";
+	dir_info[1] = pwd;
+	if (shellby_setenv(dir_info, dir_info) == -1)
+		return (-1);
+	if (args[0] && args[0][0] == '-' && args[0][1] != '-')
+	{
+		write(STDOUT_FILENO, pwd, _strlen(pwd));
+		write(STDOUT_FILENO, new_line, 1);
+	}
+	free(oldpwd);
+	free(pwd);
+	free(dir_info);
+	return (0);
+}
+
+/**
+ * shellby_help - Displays information about shellby builtin commands.
+ * @args: An array of arguments.
+ * @front: A pointer to the beginning of args.
+ *
+ * Return: If an error occurs - -1.
+ *         Otherwise - 0.
+ */
+int shellby_help(char **args, char __attribute__((__unused__)) **front)
+{
+	if (!args[0])
+		help_all();
+	else if (_strcmp(args[0], "alias") == 0)
+		help_alias();
+	else if (_strcmp(args[0], "cd") == 0)
+		help_cd();
+	else if (_strcmp(args[0], "exit") == 0)
+		help_exit();
+	else if (_strcmp(args[0], "env") == 0)
+		help_env();
+	else if (_strcmp(args[0], "setenv") == 0)
+		help_setenv();
+	else if (_strcmp(args[0], "unsetenv") == 0)
+		help_unsetenv();
+	else if (_strcmp(args[0], "help") == 0)
+		help_help();
+	else
+		write(STDERR_FILENO, name, _strlen(name));
+
+	return (0);
+}