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Shell: Implement redirections

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This works well enough. At the moment redirections can appear anywhere
in the command **after** environment variables and possible alias
command. This means commands like `>foo echo hello` are not supported.
I don't think this is big enough problem for now (99% time redirections
are given after arguments) that i would rewrite the environment and
alias parsing.
This commit is contained in:
Bananymous
2025-07-22 16:54:06 +03:00
parent 05affda20c
commit c1978f9133
8 changed files with 212 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

119
userspace/programs/Shell/TokenParser.cpp
View File

@@ -7,6 +7,7 @@
#include <BAN/ScopeGuard.h>
#include <stdio.h>
#include <unistd.h>
static constexpr bool can_parse_argument_from_token_type(Token::Type token_type)
{
@@ -18,6 +19,8 @@ static constexpr bool can_parse_argument_from_token_type(Token::Type token_type)
case Token::Type::Ampersand:
case Token::Type::CloseCurly:
case Token::Type::CloseParen:
case Token::Type::GreaterThan:
case Token::Type::LessThan:
case Token::Type::OpenCurly:
case Token::Type::OpenParen:
case Token::Type::Pipe:
@@ -43,6 +46,8 @@ static constexpr char token_type_to_single_character(Token::Type type)
case Token::Type::CloseParen: return ')';
case Token::Type::Dollar: return '$';
case Token::Type::DoubleQuote: return '"';
case Token::Type::GreaterThan: return '>';
case Token::Type::LessThan: return '<';
case Token::Type::OpenCurly: return '{';
case Token::Type::OpenParen: return '(';
case Token::Type::Pipe: return '|';
@@ -74,6 +79,10 @@ static constexpr BAN::Error unexpected_token_error(Token::Type type)
return BAN::Error::from_literal("unexpected token $");
case Token::Type::DoubleQuote:
return BAN::Error::from_literal("unexpected token \"");
case Token::Type::GreaterThan:
return BAN::Error::from_literal("unexpected token >");
case Token::Type::LessThan:
return BAN::Error::from_literal("unexpected token <");
case Token::Type::OpenCurly:
return BAN::Error::from_literal("unexpected token {");
case Token::Type::Pipe:
@@ -185,6 +194,8 @@ BAN::ErrorOr<CommandArgument::ArgumentPart> TokenParser::parse_backslash(bool is
case Token::Type::CloseParen:
case Token::Type::Dollar:
case Token::Type::DoubleQuote:
case Token::Type::GreaterThan:
case Token::Type::LessThan:
case Token::Type::OpenCurly:
case Token::Type::OpenParen:
case Token::Type::Pipe:
@@ -277,6 +288,8 @@ BAN::ErrorOr<CommandArgument::ArgumentPart> TokenParser::parse_dollar()
case Token::Type::CloseCurly:
case Token::Type::CloseParen:
case Token::Type::DoubleQuote:
case Token::Type::GreaterThan:
case Token::Type::LessThan:
case Token::Type::Pipe:
case Token::Type::Semicolon:
case Token::Type::SingleQuote:
@@ -363,6 +376,8 @@ BAN::ErrorOr<CommandArgument::ArgumentPart> TokenParser::parse_single_quote()
case Token::Type::CloseParen:
case Token::Type::Dollar:
case Token::Type::DoubleQuote:
case Token::Type::GreaterThan:
case Token::Type::LessThan:
case Token::Type::OpenCurly:
case Token::Type::OpenParen:
case Token::Type::Pipe:
@@ -403,6 +418,8 @@ BAN::ErrorOr<CommandArgument> TokenParser::parse_argument()
case Token::Type::Ampersand:
case Token::Type::CloseCurly:
case Token::Type::CloseParen:
case Token::Type::GreaterThan:
case Token::Type::LessThan:
case Token::Type::OpenCurly:
case Token::Type::OpenParen:
case Token::Type::Pipe:
@@ -466,6 +483,56 @@ BAN::ErrorOr<CommandArgument> TokenParser::parse_argument()
return result;
}
BAN::ErrorOr<SingleCommand::Redirection> TokenParser::parse_redirection()
{
int source_fd = -1;
if (peek_token().type() == Token::Type::String)
{
const auto string = read_token().string();
source_fd = 0;
for (char ch : string)
source_fd = (source_fd * 10) + (ch - '0');
}
const auto token_type = peek_token().type();
consume_token();
switch (token_type)
{
case Token::Type::GreaterThan:
if (source_fd == -1)
source_fd = STDOUT_FILENO;
break;
case Token::Type::LessThan:
if (source_fd == -1)
source_fd = STDIN_FILENO;
break;
default:
ASSERT_NOT_REACHED();
}
const bool append = (peek_token().type() == token_type);
if (append)
consume_token();
const bool duplicate = (peek_token().type() == Token::Type::Ampersand);
if (duplicate)
consume_token();
while (peek_token().type() == Token::Type::Whitespace)
consume_token();
return SingleCommand::Redirection {
.destination = TRY(parse_argument()),
.source_fd = source_fd,
.append = append,
.duplicate = duplicate,
.input = (token_type == Token::Type::LessThan),
};
}
BAN::ErrorOr<SingleCommand> TokenParser::parse_single_command()
{
SingleCommand result;
@@ -527,6 +594,8 @@ BAN::ErrorOr<SingleCommand> TokenParser::parse_single_command()
case Token::Type::CloseCurly:
case Token::Type::Dollar:
case Token::Type::DoubleQuote:
case Token::Type::GreaterThan:
case Token::Type::LessThan:
case Token::Type::OpenCurly:
case Token::Type::OpenParen:
case Token::Type::SingleQuote:
@@ -562,18 +631,56 @@ BAN::ErrorOr<SingleCommand> TokenParser::parse_single_command()
consume_token();
}
const auto can_parse_redirection =
[this]() -> bool
{
const auto& token = peek_token();
if (token.type() == Token::Type::GreaterThan)
return true;
if (token.type() == Token::Type::LessThan)
return true;
if (token.type() != Token::Type::String)
return false;
if (token.string().empty())
return false;
bool is_number = true;
for (size_t i = 0; i < token.string().size() && is_number; i++)
is_number = isdigit(token.string()[i]);
if (!is_number)
return false;
auto temp = read_token();
const bool is_redir =
(peek_token().type() == Token::Type::GreaterThan) ||
(peek_token().type() == Token::Type::LessThan);
MUST(unget_token(BAN::move(temp)));
if (!is_redir)
return false;
return true;
};
while (peek_token().type() != Token::Type::EOF_)
{
while (peek_token().type() == Token::Type::Whitespace)
consume_token();
auto argument = TRY(parse_argument());
TRY(result.arguments.push_back(BAN::move(argument)));
while (peek_token().type() == Token::Type::Whitespace)
consume_token();
if (!can_parse_argument_from_token_type(peek_token().type()))
if (can_parse_redirection())
{
auto redirection = TRY(parse_redirection());
TRY(result.redirections.push_back(BAN::move(redirection)));
}
else if (can_parse_argument_from_token_type(peek_token().type()))
{
auto argument = TRY(parse_argument());
TRY(result.arguments.push_back(BAN::move(argument)));
}
else
{
break;
}
}
return result;