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/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/* Maintenance shell */
#include <sys/reboot.h>
#include <sys/auxv.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
#include "mshell.h"
#define INPUT_SIZE 32
#define TTY_DEV "/dev/tty1"
#define PROMPT "mshell> "
struct mshell_state {
uint8_t running : 1;
char input[INPUT_SIZE];
};
static void
help(void)
{
printf(
"MSHELL COMMANDS\n"
"\thelp - show this message\n"
"\treboot - reboot the system\n"
"\ttty - show the current TTY\n"
"\tpagesize - get the current page size\n"
"\texit - exit the shell\n"
);
}
static void
parse_input(struct mshell_state *state)
{
char cmd[INPUT_SIZE];
char *p = &state->input[0];
size_t cmd_idx = 0;
/* Skip leading whitespace */
while (*p && *p == ' ')
++p;
/* Push the command */
while (*p && *p != '\n')
cmd[cmd_idx++] = *p++;
cmd[cmd_idx] = '\0';
/* Ignore empty commands */
if (cmd_idx == 0)
return;
if (strcmp(cmd, "reboot") == 0) {
reboot(REBOOT_DEFAULT);
} else if (strcmp(cmd, "pagesize") == 0) {
printf("%d\n", auxv_entry(AT_PAGESIZE));
} else if (strcmp(cmd, "tty") == 0) {
printf("%s\n", TTY_DEV);
} else if (strcmp(cmd, "help") == 0) {
help();
} else if (strcmp(cmd, "exit") == 0) {
state->running = 0;
} else {
printf("Unknown command '%s'\n", cmd);
printf("Use 'help' for help\n");
}
}
int
mshell_enter(void)
{
int fd, tmp;
size_t input_idx;
struct termios tm_old, tm;
struct mshell_state state = {
.running = 1
};
/* Try opening the TTY */
fd = open(TTY_DEV, O_RDONLY);
if (fd < 0)
return -1;
/* Set raw mode */
tcgetattr(fd, &tm_old);
tm = tm_old;
tm.c_lflag &= ~(ICANON | ECHO);
tcsetattr(fd, 0, &tm);
printf("%s", PROMPT);
input_idx = 0;
while (state.running) {
if (read(fd, &tmp, 1) <= 0)
continue;
switch (tmp) {
case '\n':
/*
* Parse the input, the newline is so that any printed
* text that is the result of a command can have
* its own lines.
*/
printf("\n");
parse_input(&state);
/* Reset the buffer */
input_idx = 0;
state.input[0] = '\0';
printf("%s", PROMPT);
fflush(stdout);
break;
case '\b':
if (input_idx > 0) {
/*
* Replace the last char with a '\0' and rewrite
* the prompt.
*/
state.input[--input_idx] = '\0';
printf("\b");
fflush(stdout);
continue;
}
break;
default:
if (input_idx < INPUT_SIZE) {
state.input[input_idx++] = tmp;
state.input[input_idx] = '\0';
printf("%c", tmp);
fflush(stdout);
}
break;
}
}
/* Restore TTY state */
tcsetattr(fd, 0, &tm_old);
close(fd);
return 0;
}
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