banan-os/userspace/Shell/main.cpp

472 lines
9.3 KiB
C++

#include <BAN/Optional.h>
#include <BAN/ScopeGuard.h>
#include <BAN/String.h>
#include <BAN/Vector.h>
#include <ctype.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <termios.h>
#include <unistd.h>
#define ERROR_RETURN(msg) { perror(msg); return 1; }
struct termios old_termios, new_termios;
BAN::Optional<BAN::String> parse_dollar(BAN::StringView command, size_t& i)
{
ASSERT(command[i] == '$');
if (++i >= command.size())
return "$"sv;
if (isalnum(command[i]))
{
size_t len = 1;
for (; i + len < command.size(); len++)
if (!isalnum(command[i + len]))
break;
BAN::String name = command.substring(i, len);
i += len - 1;
if (const char* value = getenv(name.data()))
return BAN::StringView(value);
return ""sv;
}
else if (command[i] == '{')
{
size_t len = 1;
for (; i + len < command.size(); len++)
{
if (command[i + len] == '}')
break;
if (!isalnum(command[i + len]))
return {};
}
if (i + len >= command.size())
return {};
BAN::String name = command.substring(i + 1, len - 1);
i += len;
if (const char* value = getenv(name.data()))
return BAN::StringView(value);
return ""sv;
}
else if (command[i] == '[')
{
return {};
}
else if (command[i] == '(')
{
return {};
}
return "$"sv;
}
BAN::Vector<BAN::String> parse_command(BAN::StringView command)
{
enum class State
{
Normal,
SingleQuote,
DoubleQuote,
};
BAN::Vector<BAN::String> result;
State state = State::Normal;
BAN::String current;
for (size_t i = 0; i < command.size(); i++)
{
char c = command[i];
switch (state)
{
case State::Normal:
if (c == '\'')
state = State::SingleQuote;
else if (c == '"')
state = State::DoubleQuote;
else if (c == '$')
{
auto expansion = parse_dollar(command, i);
if (!expansion.has_value())
{
fprintf(stderr, "bad substitution\n");
return {};
}
MUST(current.append(expansion.value()));
}
else if (!isspace(c))
MUST(current.push_back(c));
else
{
if (!current.empty())
{
MUST(result.push_back(current));
current.clear();
}
}
break;
case State::SingleQuote:
if (c == '\'')
state = State::Normal;
else
MUST(current.push_back(c));
break;
case State::DoubleQuote:
if (c == '"')
state = State::Normal;
else if (c != '$')
MUST(current.push_back(c));
else
{
auto expansion = parse_dollar(command, i);
if (!expansion.has_value())
{
fprintf(stderr, "bad substitution\n");
return {};
}
MUST(current.append(expansion.value()));
}
break;
}
}
// FIXME: handle state != State::Normal
MUST(result.push_back(BAN::move(current)));
return result;
}
int execute_command(BAN::StringView command)
{
auto args = parse_command(command);
if (args.empty())
return 0;
if (args.front() == "clear"sv)
{
fprintf(stdout, "\e[H\e[J");
fflush(stdout);
return 0;
}
else if (args.front() == "exit"sv)
{
exit(0);
}
else if (args.front() == "export"sv)
{
bool first = false;
for (const auto& arg : args)
{
if (first)
{
first = false;
continue;
}
auto split = MUST(arg.sv().split('=', true));
if (split.size() != 2)
continue;
if (setenv(BAN::String(split[0]).data(), BAN::String(split[1]).data(), true) == -1)
ERROR_RETURN("setenv");
}
}
else if (args.front() == "cd"sv)
{
if (args.size() > 2)
{
printf("cd: too many arguments\n");
return 1;
}
BAN::StringView path;
if (args.size() == 1)
{
if (const char* path_env = getenv("HOME"))
path = path_env;
else
return 0;
}
else
path = args[1];
if (chdir(path.data()) == -1)
ERROR_RETURN("chdir");
}
else
{
bool time = false;
if (args.front() == "time"sv)
{
args.remove(0);
time = true;
}
BAN::Vector<char*> cmd_args;
MUST(cmd_args.reserve(args.size() + 1));
for (const auto& arg : args)
MUST(cmd_args.push_back((char*)arg.data()));
MUST(cmd_args.push_back(nullptr));
timespec start;
if (time && clock_gettime(CLOCK_MONOTONIC, &start) == -1)
ERROR_RETURN("clock_gettime");
pid_t pid = fork();
if (pid == 0)
{
execv(cmd_args.front(), cmd_args.data());
perror("execv");
exit(1);
}
if (pid == -1)
ERROR_RETURN("fork");
int status;
if (waitpid(pid, &status, 0) == -1)
ERROR_RETURN("waitpid");
if (time)
{
timespec end;
if (clock_gettime(CLOCK_MONOTONIC, &end) == -1)
ERROR_RETURN("clock_gettime");
uint64_t total_ns = 0;
total_ns += (end.tv_sec - start.tv_sec) * 1'000'000'000;
total_ns += end.tv_nsec - start.tv_nsec;
printf(
"took %d.%03d s\n",
(int)( total_ns / 1'000'000'000),
(int)((total_ns % 1'000'000'000) / 1'000'000)
);
}
return status;
}
return 0;
}
int character_length(BAN::StringView prompt)
{
int length { 0 };
bool in_escape { false };
for (char c : prompt)
{
if (in_escape)
{
if (isalpha(c))
in_escape = false;
}
else
{
if (c == '\e')
in_escape = true;
else if (((uint8_t)c & 0xC0) != 0x80)
length++;
}
}
return length;
}
BAN::String get_prompt()
{
const char* raw_prompt = getenv("PS1");
if (raw_prompt == nullptr)
return ""sv;
BAN::String prompt;
for (int i = 0; raw_prompt[i]; i++)
{
char ch = raw_prompt[i];
if (ch == '\\')
{
switch (raw_prompt[++i])
{
case 'e':
MUST(prompt.push_back('\e'));
break;
case 'n':
MUST(prompt.push_back('\n'));
break;
case '\\':
MUST(prompt.push_back('\\'));
break;
case '~':
{
char buffer[256];
if (getcwd(buffer, sizeof(buffer)) == nullptr)
strcpy(buffer, strerrorname_np(errno));
const char* home = getenv("HOME");
size_t home_len = home ? strlen(home) : 0;
if (home && strncmp(buffer, home, home_len) == 0)
{
MUST(prompt.push_back('~'));
MUST(prompt.append(buffer + home_len));
}
else
{
MUST(prompt.append(buffer));
}
break;
}
case '\0':
MUST(prompt.push_back('\\'));
break;
default:
MUST(prompt.push_back('\\'));
MUST(prompt.push_back(*raw_prompt));
break;
}
}
else
{
MUST(prompt.push_back(ch));
}
}
return prompt;
}
int prompt_length()
{
return character_length(get_prompt());
}
void print_prompt()
{
auto prompt = get_prompt();
fprintf(stdout, "%.*s", prompt.size(), prompt.data());
fflush(stdout);
}
int main(int argc, char** argv)
{
if (argc >= 1)
setenv("SHELL", argv[0], true);
setenv("PS1", "\e[32muser@host\e[m:\e[34m\\~\e[m$ ", false);
tcgetattr(0, &old_termios);
new_termios = old_termios;
new_termios.c_lflag &= ~(ECHO | ICANON);
tcsetattr(0, TCSANOW, &new_termios);
BAN::Vector<BAN::String> buffers, history;
MUST(buffers.emplace_back(""sv));
size_t index = 0;
size_t col = 0;
int waiting_utf8 = 0;
print_prompt();
while (true)
{
uint8_t ch;
fread(&ch, 1, sizeof(char), stdin);
if (waiting_utf8 > 0)
{
waiting_utf8--;
ASSERT((ch & 0xC0) == 0x80);
fputc(ch, stdout);
MUST(buffers[index].insert(ch, col++));
if (waiting_utf8 == 0)
{
fprintf(stdout, "\e[s%s\e[u", buffers[index].data() + col);
fflush(stdout);
}
continue;
}
else if (ch & 0x80)
{
if ((ch & 0xE0) == 0xC0)
waiting_utf8 = 1;
else if ((ch & 0xF0) == 0xE0)
waiting_utf8 = 2;
else if ((ch & 0xF8) == 0xF0)
waiting_utf8 = 3;
else
ASSERT_NOT_REACHED();
fputc(ch, stdout);
MUST(buffers[index].insert(ch, col++));
continue;
}
switch (ch)
{
case '\e':
fread(&ch, 1, sizeof(char), stdin);
if (ch != '[')
break;
fread(&ch, 1, sizeof(char), stdin);
switch (ch)
{
case 'A': if (index > 0) { index--; col = buffers[index].size(); fprintf(stdout, "\e[%dG%s\e[K", prompt_length() + 1, buffers[index].data()); fflush(stdout); } break;
case 'B': if (index < buffers.size() - 1) { index++; col = buffers[index].size(); fprintf(stdout, "\e[%dG%s\e[K", prompt_length() + 1, buffers[index].data()); fflush(stdout); } break;
case 'C': if (col < buffers[index].size()) { col++; while ((buffers[index][col - 1] & 0xC0) == 0x80) col++; fprintf(stdout, "\e[C"); fflush(stdout); } break;
case 'D': if (col > 0) { while ((buffers[index][col - 1] & 0xC0) == 0x80) col--; col--; fprintf(stdout, "\e[D"); fflush(stdout); } break;
}
break;
case '\x0C': // ^L
{
int x = prompt_length() + character_length(buffers[index].sv().substring(col)) + 1;
fprintf(stdout, "\e[H\e[J");
print_prompt();
fprintf(stdout, "%s\e[u\e[1;%dH", buffers[index].data(), x);
fflush(stdout);
break;
}
case '\b':
if (col > 0)
{
while ((buffers[index][col - 1] & 0xC0) == 0x80)
buffers[index].remove(--col);
buffers[index].remove(--col);
fprintf(stdout, "\b\e[s%s \e[u", buffers[index].data() + col);
fflush(stdout);
}
break;
case '\n':
fputc('\n', stdout);
if (!buffers[index].empty())
{
tcsetattr(0, TCSANOW, &old_termios);
execute_command(buffers[index]);
tcsetattr(0, TCSANOW, &new_termios);
MUST(history.push_back(buffers[index]));
buffers = history;
MUST(buffers.emplace_back(""sv));
}
print_prompt();
index = buffers.size() - 1;
col = 0;
break;
default:
MUST(buffers[index].insert(ch, col++));
fprintf(stdout, "%c\e[s%s\e[u", ch, buffers[index].data() + col);
fflush(stdout);
break;
}
}
tcsetattr(0, TCSANOW, &old_termios);
return 0;
}