Files
operating-systems/chp3_process/osh_shell/osh.c
Fabio Scotto di Santolo 93b92cf5c6 Update osh.c
2024-09-15 21:06:10 +02:00

148 lines
3.0 KiB
C

#include "history.h"
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
struct command_t {
char **args;
bool bg_flag;
};
struct command_t parse_command(char *);
int digits(char *);
int main(void) {
// Create and/or read history file
int history_count = allocate_history();
if (history_count < 0) {
perror("Error");
exit(EXIT_FAILURE);
}
int should_run = 1;
while (should_run) {
char raw[MAXLEN / 2 + 1];
printf("osh> ");
fflush(stdout);
fgets(raw, MAXLEN / 2 + 1, stdin);
// check if user press newline
if (strcmp(raw, "\n") == 0) {
continue;
}
// FIXME: handle ^D shortcut
if (strcmp(raw, "\000") == 0) {
exit(EXIT_SUCCESS);
}
char *c;
if (strcmp(raw, "!!\n") == 0) {
if (nth_command(raw, history_count) != -1) {
printf("%s\n", raw);
} else {
fprintf(stderr, "History is empty\n");
continue;
}
} else if ((c = strchr(raw, '!')) != NULL) {
const int n = digits(c);
if (nth_command(raw, n) != -1) {
printf("%s\n", raw);
} else {
fprintf(stderr, "Command not found in position %d\n", n);
continue;
}
}
// remove carriage return
raw[strlen(raw) - 1] = '\0';
// save command in the history file
history_count = add_history(history_count, raw);
struct command_t cmd = parse_command(raw);
if (strcmp(cmd.args[0], "exit") == 0) {
should_run = 0;
} else if (strcmp(cmd.args[0], "history") == 0) {
// print on the stdout last 10 commands in reverse way
history_entry_t *history = get_history(history_count);
for (int i = HISTORY_SIZE - 1; i >= 0; i--) {
history_entry_t entry = history[i];
if (entry.line_number != 0) {
printf("%5d\t%s", entry.line_number, entry.command);
}
}
free(history);
history = NULL;
} else {
pid_t pid = fork();
switch (pid) {
case -1:
perror("Fork\n");
exit(EXIT_FAILURE);
case 0:
should_run = 0;
if (execvp(cmd.args[0], cmd.args)) {
perror("Error");
}
break;
default:
if (!cmd.bg_flag) {
wait(NULL);
}
break;
}
}
free(cmd.args);
cmd.args = NULL;
}
return EXIT_SUCCESS;
}
struct command_t parse_command(char *raw) {
int i = 0;
bool bg_flag = false;
char **args = (char **)calloc(MAXLEN, sizeof(char *));
char *tok = strtok(raw, " ");
while (tok != NULL) {
if (strcmp(tok, "&") == 0) {
bg_flag = true;
} else {
args[i] = tok;
}
tok = strtok(NULL, " ");
i++;
}
struct command_t cmd = {.args = args, .bg_flag = bg_flag};
return cmd;
}
int digits(char *s) {
char *sub = malloc(strlen(s) * sizeof(s));
char c;
int i = 0, j = 0;
while ((c = s[i]) != '\n') {
if (isdigit(c)) {
sub[j++] = c;
}
i++;
}
int n = atoi(sub);
free(sub);
sub = NULL;
return n;
}