initial commit

.gitignore

@@ -0,0 +1,5 @@
+build/
+.vscode/
+a.out
+val/
+tmp*

Makefile

@@ -0,0 +1,29 @@
+TARGET_EXEC ?= msh
+
+BUILD_DIR ?= ./build
+SRC_DIRS ?= ./src
+
+SRCS := $(shell find $(SRC_DIRS) -name *.c)
+OBJS := $(SRCS:%=$(BUILD_DIR)/%.o)
+DEPS := $(OBJS:.o=.d)
+
+INC_DIRS := $(shell find $(SRC_DIRS) -type d)
+INC_FLAGS := $(addprefix -I,$(INC_DIRS))
+
+CPPFLAGS ?= $(INC_FLAGS) -MMD -MP
+
+$(BUILD_DIR)/$(TARGET_EXEC): $(OBJS)
+	$(CC) -ggdb3 $(OBJS) -o $@ $(LDFLAGS)
+
+$(BUILD_DIR)/%.c.o: %.c
+	$(MKDIR_P) $(dir $@)
+	$(CC) -ggdb3 $(CPPFLAGS) $(CFLAGS) -c $< -o $@
+
+.PHONY: clean
+
+clean:
+	$(RM) -r $(BUILD_DIR)
+
+-include $(DEPS)
+
+MKDIR_P ?= mkdir -p

include/input.h

@@ -0,0 +1,25 @@
+#ifndef _INPUT_H
+#define _INPUT_H
+
+#include <termio.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+enum keys {
+    DELETE_KEY = 1000,
+    LEFT_KEY,
+    RIGHT_KEY,
+    HOME_KEY,
+    END_KEY,
+    BACKSPACE_KEY,
+    ENTER_KEY,
+    TAB_KEY,
+    ESCAPE_KEY,
+    CTRL_C_KEY
+};
+
+void change_mode(int on);
+char *read_line(char **line);
+int process_keypress(char c);
+
+#endif

include/keys.h

@@ -0,0 +1,15 @@
+#ifndef _KEYS_H
+#define _KEYS_H
+
+#include <stdlib.h>
+
+void delete_key(int pos, int *n, char **line);
+void move_left(int *pos);
+void move_right(int *pos, int n);
+void home_key(int *pos);
+void end_key(int *pos, int n);
+void backspace_key(int *pos, int *n, char **line);
+void new_line();
+void printable_key(int *pos, int *n, char c, char **line);
+
+#endif

include/output.h

@@ -0,0 +1,11 @@
+#ifndef _OUTPUT_H
+#define _OUTPUT_H
+
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+size_t append_to_buff(char **buff, size_t *buff_size, char *ap, size_t ap_size);
+void print_str(char *buff, size_t size);
+
+#endif

include/shell.h

@@ -0,0 +1,28 @@
+#ifndef _SHELL_H
+#define _SHELL_H
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#define BUFF_SIZE 1024
+#define ARG_SIZE 32
+
+char *read_line();
+void process_line(char *line, char ***args);
+int launch(char **args);
+void process_command();
+int execute(char **args);
+
+void sig_handler();
+
+int sh_cd(char **args);
+int sh_exit(char **args);
+
+#define BUILTIN_NUM sizeof(builtin) / sizeof(char *)
+
+#endif

include/utils.h

@@ -0,0 +1,14 @@
+#ifndef _UTILS_H
+#define _UTILS_H
+
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+void die(char *s);
+void append_to_pos(char **str, int pos, char ch);
+void remove_on_pos(char **str, int pos);
+
+#endif

src/input.c

@@ -0,0 +1,173 @@
+#include "../include/input.h"
+#include "../include/keys.h"
+
+/**
+ * @brief Switches console raw mode
+ * 
+ * @param on 
+ */
+void change_mode(int on)
+{
+    static struct termios oldt, newt;
+
+    if (on)
+    {
+        tcgetattr(STDIN_FILENO, &oldt);
+        newt = oldt;
+        newt.c_lflag &= ~(ICANON | ECHO);
+        tcsetattr(STDIN_FILENO, TCSANOW, &newt);
+    }
+    else
+        tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
+}
+
+/**
+ * @brief Reads line from user input and puts it into "line"
+ * 
+ * @param line 
+ * @return char* 
+ */
+char *read_line(char **line)
+{
+    int c;
+    int n = 0, pos = 0;
+
+    while (read(STDIN_FILENO, &c, 1))
+    {
+        c = process_keypress(c);
+
+        if (c)
+        {
+            switch (c)
+            {
+            case DELETE_KEY:
+                delete_key(pos, &n, line);
+                break;
+
+            case LEFT_KEY:
+                move_left(&pos);
+                break;
+
+            case RIGHT_KEY:
+                move_right(&pos, n);
+                break;
+
+            case HOME_KEY:
+                home_key(&pos);
+                break;
+
+            case END_KEY:
+                end_key(&pos, n);
+                break;
+
+            case BACKSPACE_KEY:
+                backspace_key(&pos, &n, line);
+                break;
+
+            case ENTER_KEY:
+                new_line();
+
+                return *line;
+                break;
+
+            case TAB_KEY:
+            {
+                // char *buff = malloc(1);
+                // buff[0] = '\0';
+                // size_t buff_size = 1;
+
+                // n += 2;
+                // append_to_buff(&buff, &buff_size, "  ", 2);
+                // for (int i = 0; i < 2; i++)
+                //     append_to_pos(line, pos, ' ');
+                // append_to_buff(&buff, &buff_size, "\0337", 2);
+                // pos += 2;
+                // append_to_buff(&buff, &buff_size, *line + pos, n - pos);
+                // append_to_buff(&buff, &buff_size, "\0338", 2);
+
+                // print_str(buff, buff_size);
+
+                // TODO: autocomplete
+            }
+            break;
+
+            case ESCAPE_KEY:
+                break;
+
+            default:
+                if ((c > 31 && c < 127) || (c > 127 && c < 255))
+                    printable_key(&pos, &n, (char)c, line);
+
+                break;
+            }
+        }
+    }
+}
+
+/**
+ * @brief Processes user keypress, filters special characters
+ * 
+ * @param c 
+ * @return int 
+ */
+int process_keypress(char c)
+{
+    char seq[3];
+    if (c == '\x1b')
+    {
+        for (int i = 0; i < 2; i++)
+            if (read(STDIN_FILENO, &seq[i], 1) == -1)
+                return ESCAPE_KEY;
+        if (seq[0] == '[')
+        {
+            if (seq[1] >= '0' && seq[1] <= '9')
+            {
+                read(STDIN_FILENO, &seq[2], 1);
+                if (seq[2] == '~')
+                {
+                    switch (seq[1])
+                    {
+                    case '3':
+                        return DELETE_KEY;
+                        break;
+                    }
+                }
+            }
+            switch (seq[1])
+            {
+            case 'D':
+                return LEFT_KEY;
+                break;
+
+            case 'C':
+                return RIGHT_KEY;
+                break;
+
+            case 'H':
+                return HOME_KEY;
+                break;
+
+            case 'F':
+                return END_KEY;
+                break;
+            }
+        }
+        return ESCAPE_KEY;
+    }
+    else if (c == 127)
+    {
+        return BACKSPACE_KEY;
+    }
+    else if (c == '\n')
+    {
+        return ENTER_KEY;
+    }
+    else if (c == '\t')
+    {
+        return TAB_KEY;
+    }
+    else
+    {
+        return c;
+    }
+}

src/keys.c

@@ -0,0 +1,114 @@
+#include "../include/keys.h"
+#include "../include/output.h"
+#include "../include/utils.h"
+
+void delete_key(int pos, int *n, char **line)
+{
+    if (pos < *n)
+    {
+        remove_on_pos(line, pos + 1);
+        (*n)--;
+
+        char *buff = malloc(1);
+        buff[0] = '\0';
+        size_t buff_size = 1;
+
+        append_to_buff(&buff, &buff_size, "\0337", 2);
+        append_to_buff(&buff, &buff_size, *line + pos, *n - pos);
+        append_to_buff(&buff, &buff_size, " ", 1);
+        append_to_buff(&buff, &buff_size, "\0338", 2);
+
+        print_str(buff, buff_size);
+    }
+}
+
+void move_left(int *pos)
+{
+    if (*pos > 0)
+    {
+        print_str("\033[D", 3);
+        (*pos)--;
+    }
+}
+
+void move_right(int *pos, int n)
+{
+    if (*pos < n)
+    {
+        print_str("\033[C", 3);
+        (*pos)++;
+    }
+}
+
+void home_key(int *pos)
+{
+    char *buff = malloc(1);
+    buff[0] = '\0';
+    size_t buff_size = 1;
+
+    for (int i = 0; i < *pos; i++)
+        append_to_buff(&buff, &buff_size, "\033[D", 3);
+
+    print_str(buff, buff_size);
+    *pos = 0;
+}
+
+void end_key(int *pos, int n)
+{
+    char *buff = malloc(1);
+    buff[0] = '\0';
+    size_t buff_size = 1;
+
+    for (int i = 0; i < n - *pos; i++)
+        append_to_buff(&buff, &buff_size, "\033[C", 3);
+
+    print_str(buff, buff_size);
+
+    *pos = n;
+}
+
+void backspace_key(int *pos, int *n, char **line)
+{
+    if (*pos > 0)
+    {
+        remove_on_pos(line, *pos);
+        (*n)--;
+        (*pos)--;
+
+        char *buff = malloc(1);
+        buff[0] = '\0';
+        size_t buff_size = 1;
+
+        append_to_buff(&buff, &buff_size, "\033[D", 3);
+        append_to_buff(&buff, &buff_size, "\0337", 2);
+        append_to_buff(&buff, &buff_size, *line + *pos, *n - *pos);
+        append_to_buff(&buff, &buff_size, " ", 1);
+        append_to_buff(&buff, &buff_size, "\0338", 2);
+
+        print_str(buff, buff_size);
+    }
+}
+
+void new_line()
+{
+    print_str("\n", 1);
+}
+
+void printable_key(int *pos, int *n, char c, char **line)
+{
+    char *buff = malloc(1);
+    buff[0] = '\0';
+    size_t buff_size = 1;
+
+    (*n)++;
+    append_to_buff(&buff, &buff_size, &c, 1);
+
+    append_to_pos(line, *pos, c);
+
+    append_to_buff(&buff, &buff_size, "\0337", 2);
+    (*pos)++;
+    append_to_buff(&buff, &buff_size, *line + *pos, *n - *pos);
+    append_to_buff(&buff, &buff_size, "\0338", 2);
+
+    print_str(buff, buff_size);
+}

src/main.c

@@ -0,0 +1,23 @@
+#include <signal.h>
+
+#include "../include/input.h"
+#include "../include/utils.h"
+#include "../include/shell.h"
+
+void exit_shell()
+{
+    change_mode(0);
+}
+
+int main(int argc, char **argv)
+{
+    change_mode(1);
+    signal(SIGINT, SIG_IGN);
+
+    atexit(exit_shell);
+
+    while (1)
+    {
+        process_command();
+    }
+}

src/output.c

@@ -0,0 +1,17 @@
+#include "../include/output.h"
+
+size_t append_to_buff(char **buff, size_t *buff_size, char *ap, size_t ap_size)
+{
+    *buff = realloc(*buff, *buff_size + ap_size);
+    memcpy(*buff + *buff_size - 1, ap, ap_size);
+
+    *buff_size += ap_size;
+    (*buff)[*buff_size - 1] = '\0';
+
+    return *buff_size;
+}
+
+void print_str(char *buff, size_t size)
+{
+    write(STDOUT_FILENO, buff, size);
+}

src/shell.c

@@ -0,0 +1,156 @@
+#include "../include/shell.h"
+#include "../include/input.h"
+#include "../include/output.h"
+
+/* Global definitions */
+char *builtin[] = {
+    "cd",
+    "exit"};
+
+int (*builtin_func[])(char **) = {
+    &sh_cd,
+    &sh_exit};
+
+/**
+ * @brief Function for main loop. It prints prompt, reads user's input and executes it
+ */
+void process_command()
+{
+    char **args;
+    int status;
+
+    do
+    {
+        char *line = malloc(1);
+        line[0] = '\0';
+
+        if (getuid() == 0)
+            print_str("# ", 2);
+        else
+            print_str("> ", 2);
+
+        line = read_line(&line);
+
+        process_line(line, &args);
+        status = execute(args);
+
+        free(line);
+        free(args);
+    } while (status);
+}
+
+/**
+ * @brief Extracts command and its arguments from line
+ * 
+ * @param line 
+ * @param args 
+ */
+void process_line(char *line, char ***args)
+{
+    int buff_size = ARG_SIZE, pos = 0;
+    *args = malloc(buff_size * sizeof(char *));
+    char *tok, *rest = strdup(line);
+
+    while ((tok = strtok_r(rest, " \t", &rest)) != NULL)
+    {
+        (*args)[pos] = tok;
+        pos++;
+
+        if (pos > buff_size)
+        {
+            buff_size += ARG_SIZE;
+            *args = realloc(*args, buff_size * sizeof(char *));
+            if (*args == NULL)
+            {
+                fprintf(stderr, "myshell: allocation error");
+                exit(EXIT_FAILURE);
+            }
+        }
+    }
+
+    (*args)[pos] = NULL;
+}
+
+/**
+ * @brief Executes either builtin or system command
+ * 
+ * @param args 
+ * @return int 
+ */
+int execute(char **args)
+{
+    if (args[0] == NULL)
+        return 1;
+
+    for (int i = 0; i < BUILTIN_NUM; i++)
+        if (strcmp(args[0], builtin[i]) == 0)
+            return (*builtin_func[i])(args);
+
+    return launch(args);
+}
+
+/**
+ * @brief Launches separate process and executes specified command
+ * 
+ * @param args 
+ * @return int 
+ */
+int launch(char **args)
+{
+    pid_t pid, wpid;
+    int status;
+
+    pid = fork();
+
+    if (pid == 0)
+    {
+        change_mode(0);
+        signal(SIGINT, SIG_DFL);
+
+        if (execvp(args[0], args) < 0)
+        {
+            perror("myshell");
+        }
+
+        exit(EXIT_FAILURE);
+    }
+    else if (pid < 0)
+    {
+        perror("myshell");
+    }
+    else
+        do
+            wpid = waitpid(pid, &status, WUNTRACED);
+        while (!WIFEXITED(status) && !WIFSIGNALED(status));
+
+    change_mode(1);
+
+    return status;
+}
+
+/**
+ * @brief Shell builtin command. Changes current working directory
+ * 
+ * @param args 
+ * @return int 
+ */
+int sh_cd(char **args)
+{
+    if (args[1] == NULL)
+        fprintf(stderr, "myshell: expected arguments for \"cd\"\n");
+    else if (chdir(args[1]) < 0)
+        perror("myshell");
+
+    return 1;
+}
+
+/**
+ * @brief Shell builtin command. Exits shell
+ * 
+ * @param args 
+ * @return int 
+ */
+int sh_exit(char **args)
+{
+    exit(0);
+}

src/utils.c

@@ -0,0 +1,33 @@
+#include "../include/utils.h"
+
+void die(char *s)
+{
+    perror(s);
+    exit(1);
+}
+
+void append_to_pos(char **str, int pos, char ch)
+{
+    size_t len = strlen(*str);
+
+    *str = realloc(*str, len + 2);
+
+    for (int i = len; i >= pos; i--)
+    {
+        (*str)[i + 1] = (*str)[i];
+    }
+    (*str)[pos] = ch;
+    (*str)[len + 1] = '\0';
+}
+
+void remove_on_pos(char **str, int pos)
+{
+    size_t len = strlen(*str);
+
+    for (int i = pos - 1; i <= len; i++)
+    {
+        (*str)[i] = (*str)[i + 1];
+    }
+    (*str)[len] = '\0';
+    *str = realloc(*str, len);
+}