diff --git a/Main.c b/Main.c
index dc945ef525eb701af3769e418befbcb3b1267188..f382d96c3fb56e054f621cdd8bc6e28848a0525c 100644
--- a/Main.c
+++ b/Main.c
@@ -19,13 +19,19 @@
* At the very least, up to four pipes (such as the following)
* ls -l | grep a | grep b | grep c | grep v
* appears to work with no issues or memory leaks.
+ *
+ * Adding a single & (seperated by spaces) at the end of a command enables backgrounding.
+ * The parent will create a child that runs off to do provided command.
+ * Parent will meanwhile forget about child and prompt for further input.
*/
/**
* Known Issues:
* Does not handle < or > symbols.
- * Does not handle backgrounding (& symbol).
+
+ * Backgrounding slightly messes up user interface display.
+ * Should correct after inputing another command.
*/
@@ -70,6 +76,8 @@ typedef struct{
int argc;
char*** argv;
} makeargv_struct;
+int run_program; // Holds if program should continue to run.
+char* user_input; // Holds user input value.
makeargv_struct* line_argv; // Pointer to makeargv struct.
makeargv_struct* command_argv; // Pointer to/array of makeargv structs.
@@ -77,6 +85,7 @@ makeargv_struct* command_argv; // Pointer to/array of makeargv structs.
// Method Declaration.
int makeargv(); // Creates argv using passed line.
+void main_loop(); // Main program loop.
void parse_line(); // Parses provided line into commands.
void parse_command(); // Further parses line into smaller subsections.
void execute_command(); // Executes provided command.
@@ -86,7 +95,11 @@ char* get_directory_path(); // Gets full pathname of current directory.
void get_umask(); // Gets current umask value.
void set_umask(); // Sets umask value.
void interupt_handler(); // Handler for ctrl+c signal.
+int check_for_backgrounding(); // Check for backgrounding (&) at end of input.
+void run_backgrounding(); // Runs child processes in background.
void free_memory(); // Frees memory of vars.
+void free_line_argv(); // Frees memory of line_argv.
+void free_command_argv(); // Frees memory of line_argv.
void make_arg_example();
@@ -96,16 +109,16 @@ void make_arg_example();
* Initializes and runs program.
*/
int main(int argc, char* argv[]) {
- int run_program = 1;
- char* user_input;
+ int backgrounding_bool;
char* current_directory;
- struct sigaction action;
+ //struct sigaction action;
+ run_program = 1;
// Set ctrl+c signal interupt.
- memset(&action, '\0', sizeof(action));
- action.sa_handler = interupt_handler;
- action.sa_flags = SA_RESTART;
- sigaction(SIGINT, &action, NULL);
+ // memset(&action, '\0', sizeof(action));
+ // action.sa_handler = interupt_handler;
+ // action.sa_flags = SA_RESTART;
+ // sigaction(SIGINT, &action, NULL);
// parse_line("");
// free_memory();
@@ -142,81 +155,99 @@ int main(int argc, char* argv[]) {
// Run until user willingly quits.
while (run_program == 1) {
- current_directory = get_directory_path();
+ // Get user input and output current dir.
+ current_directory = get_directory_path();
printf(ANSI_COLOR_BLUE "%s$ " ANSI_COLOR_RESET, current_directory);
user_input = get_user_input_with_prompt("");
free(current_directory);
- parse_line(user_input);
- free(user_input);
- // Make sure at least one command is present.
- if (line_argv->argc > 0) {
- parse_command();
+ // Check for backgrounding.
+ backgrounding_bool = check_for_backgrounding();
- // Check if exit program.
- if (strcmp(**command_argv->argv, "exit") == 0) {
- run_program = 0;
+ // Run based on backgrounding bool.
+ if (backgrounding_bool == 1) {
+ run_backgrounding();
+ } else {
+ parse_line();
+ free(user_input);
+ main_loop();
+ }
+ }
- // Check for cd command.
- } else if (strcmp(**command_argv->argv, "cd") == 0) {
- if (line_argv->argc > 1) {
- err_msg("Too many arguments.");
- } else {
- if (command_argv->argc < 2) {
- err_msg("Need path argument.");
- } else if (command_argv->argc > 2) {
- err_msg("Too many arguments.");
- } else {
- change_directory(*(*command_argv->argv + 1));
- }
- }
+ return 0;
+}
- // Check for pwd command.
- } else if (strcmp(**command_argv->argv, "pwd") == 0) {
- if (line_argv->argc > 1) {
- err_msg("Too many arguments.");
- } else if (command_argv->argc > 1) {
+
+void main_loop() {
+ char* current_directory;
+
+ // Make sure at least one command is present.
+ if (line_argv->argc > 0) {
+ parse_command();
+
+ // Check if exit program.
+ if (strcmp(**command_argv->argv, "exit") == 0) {
+ run_program = 0;
+
+ // Check for cd command.
+ } else if (strcmp(**command_argv->argv, "cd") == 0) {
+ if (line_argv->argc > 1) {
+ err_msg("Too many arguments.");
+ } else {
+ if (command_argv->argc < 2) {
+ err_msg("Need path argument.");
+ } else if (command_argv->argc > 2) {
err_msg("Too many arguments.");
} else {
- current_directory = get_directory_path();
- printf("%s\n", current_directory);
- free(current_directory);
+ change_directory(*(*command_argv->argv + 1));
}
+ }
- // Check for umask command.
- } else if (strcmp(**command_argv->argv, "umask") == 0) {
- if (line_argv->argc > 1) {
+ // Check for pwd command.
+ } else if (strcmp(**command_argv->argv, "pwd") == 0) {
+ if (line_argv->argc > 1) {
+ err_msg("Too many arguments.");
+ } else if (command_argv->argc > 1) {
+ err_msg("Too many arguments.");
+ } else {
+ current_directory = get_directory_path();
+ printf("%s\n", current_directory);
+ free(current_directory);
+ }
+
+ // Check for umask command.
+ } else if (strcmp(**command_argv->argv, "umask") == 0) {
+ if (line_argv->argc > 1) {
+ err_msg("Too many arguments.");
+ } else {
+ if (command_argv->argc > 2) {
err_msg("Too many arguments.");
+ } else if (command_argv->argc < 2) {
+ get_umask();
} else {
- if (command_argv->argc > 2) {
- err_msg("Too many arguments.");
- } else if (command_argv->argc < 2) {
- get_umask();
- } else {
- set_umask(*(*command_argv->argv + 1));
- }
+ set_umask(*(*command_argv->argv + 1));
}
-
- // Attempt to exec command.
- } else {
- execute_command();
}
- free_memory();
+
+ // Attempt to exec command.
+ } else {
+ execute_command();
}
+ //free_memory();
+ free_command_argv();
+ free_line_argv();
}
-
- return 0;
}
/**
* Parses given line into subsections, separated by pipes.
*/
-void parse_line(char* command_line) {
+void parse_line() {
line_argv = calloc(1, sizeof(makeargv_struct));
line_argv->argv = calloc(1, sizeof(char***));
- line_argv->argc = makeargv(command_line, "|", line_argv->argv);
+ line_argv->argc = makeargv(user_input, "|", line_argv->argv);
// Check for errors.
if (line_argv->argc < 0) {
@@ -322,9 +353,12 @@ void recursive_execute(int argc, makeargv_struct* args, int current_arg) {
++temp_pointer;
index++;
}
+
if (execvp(**temp_pointer->argv, *temp_pointer->argv) == -1) {
err_msg("Invalid exec arg(s).");
- free_memory();
+ //free_memory();
+ free_command_argv();
+ free_line_argv();
exit(-1);
}
}
@@ -442,6 +476,72 @@ void interupt_handler() {
}
+/**
+ * Checks for "&" char at end of user's input.
+ */
+int check_for_backgrounding() {
+ int index = 0;
+ int backgrounding_bool = 0;
+ char* token;
+ char* temp_string;
+
+ // Go to last index of string.
+ while (index < strlen(user_input)) {
+ index++;
+ }
+
+ // Check for backgrounding char as last "valid" char.
+ while ((user_input[index] == '\0') ||
+ (user_input[index] == '\n') ||
+ (user_input[index] == ' ') ||
+ (user_input[index] == '&')) {
+ if (user_input[index] == '&') {
+ if (user_input[index - 1] == ' ') {
+ backgrounding_bool = 1;
+ }
+ }
+ index--;
+ }
+ index++;
+
+ // If background char was found, seperate out token.
+ if (backgrounding_bool == 1) {
+ token = strtok_r(user_input, "&", &temp_string);
+ }
+
+ return backgrounding_bool;
+}
+
+
+/**
+ * Starts a child process to run given commands.
+ * Parent can still continue as normal.
+ */
+void run_backgrounding() {
+ pid_t pid;
+
+ parse_line();
+ free(user_input);
+
+ switch(pid = fork()) {
+ case 0: // Child.
+ printf("\n");
+ main_loop();
+ exit(-1);
+ break;
+
+ case -1: // Error.
+ err_sys("Fork Error.");
+ break;
+
+ default: // Parent.
+ // Do nothing. Want to progress regardless of child.
+ break;
+ }
+ free_line_argv();
+}
+
+
/**
* Frees memory of main program variables.
*/
@@ -471,6 +571,37 @@ void free_memory() {
}
+/**
+ * Frees all line_argv values.
+ */
+void free_line_argv() {
+ free(**line_argv->argv);
+ free(*line_argv->argv);
+ free(line_argv->argv);
+ free(line_argv);
+}
+
+
+/**
+ * Frees all command_argv values.
+ */
+void free_command_argv() {
+ makeargv_struct* temp_pointer;
+ makeargv_struct* orig_pointer = command_argv;
+
+ while (line_argv->argc > 0) {
+ temp_pointer = command_argv;
+ ++temp_pointer;
+ free(*(*command_argv->argv));
+ free(*(command_argv->argv));
+ free(command_argv->argv);
+ command_argv = temp_pointer;
+ line_argv->argc--;
+ }
+ free(orig_pointer);
+}
+
+
/**
* Example of using makeargv.
*/