From dfcd15e7c42444ae9d98ec3fd66b52974058960c Mon Sep 17 00:00:00 2001 From: Bananymous Date: Mon, 7 Oct 2024 16:51:19 +0300 Subject: [PATCH] Shell: Implement background processes with & --- userspace/programs/Shell/main.cpp | 47 ++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 10 deletions(-) diff --git a/userspace/programs/Shell/main.cpp b/userspace/programs/Shell/main.cpp index 2e11d8544c..a16027c70c 100644 --- a/userspace/programs/Shell/main.cpp +++ b/userspace/programs/Shell/main.cpp @@ -36,6 +36,7 @@ struct SingleCommand struct PipedCommand { + bool background; BAN::Vector commands; }; @@ -353,7 +354,14 @@ static SingleCommand parse_single_command(BAN::StringView command_view, bool par static PipedCommand parse_piped_command(BAN::StringView command_view) { + while (!command_view.empty() && isspace(command_view.back())) + command_view = command_view.substring(0, command_view.size() - 1); + const bool background = !command_view.empty() && command_view.back() == '&'; + if (background) + command_view = command_view.substring(0, command_view.size() - 1); + PipedCommand result; + result.background = background; for (size_t i = 0; i < command_view.size(); i++) { @@ -448,7 +456,7 @@ static CommandList parse_command_list(BAN::StringView command_view) return BAN::move(result); } -static int execute_command(const SingleCommand& command, int fd_in, int fd_out); +static int execute_command(const SingleCommand& command, int fd_in, int fd_out, bool background); static int source_script(const BAN::String& path); @@ -644,7 +652,7 @@ static void install_builtin_commands() if (clock_gettime(CLOCK_MONOTONIC, &start) == -1) ERROR_RETURN("clock_gettime", 1); - int ret = execute_command(timed_command, fd_in, fd_out); + int ret = execute_command(timed_command, fd_in, fd_out, false); if (clock_gettime(CLOCK_MONOTONIC, &end) == -1) ERROR_RETURN("clock_gettime", 1); @@ -678,7 +686,7 @@ static void install_builtin_commands() )); } -static pid_t execute_command_no_wait(const SingleCommand& command, int fd_in, int fd_out, pid_t pgrp) +static pid_t execute_command_no_wait(const SingleCommand& command, int fd_in, int fd_out, pid_t pgrp, bool background) { ASSERT(!command.arguments.empty()); @@ -761,7 +769,9 @@ static pid_t execute_command_no_wait(const SingleCommand& command, int fd_in, in if (pid == -1) ERROR_RETURN("fork", -1); - if (pgrp == 0 && isatty(0)) + if (background) + ; + else if (pgrp == 0 && isatty(0)) { if(setpgid(pid, pid) == -1) perror("setpgid"); @@ -776,11 +786,13 @@ static pid_t execute_command_no_wait(const SingleCommand& command, int fd_in, in return pid; } -static int execute_command(const SingleCommand& command, int fd_in, int fd_out) +static int execute_command(const SingleCommand& command, int fd_in, int fd_out, bool background) { - const pid_t pid = execute_command_no_wait(command, fd_in, fd_out, 0); + const pid_t pid = execute_command_no_wait(command, fd_in, fd_out, 0, background); if (pid == -1) return 1; + if (background) + return 0; int status; if (waitpid(pid, &status, 0) == -1) @@ -805,7 +817,7 @@ static int execute_piped_commands(const PipedCommand& piped_command) auto& command = piped_command.commands.front(); if (auto ret = execute_builtin(command, STDIN_FILENO, STDOUT_FILENO); ret.has_value()) return ret.value(); - return execute_command(command, STDIN_FILENO, STDOUT_FILENO); + return execute_command(command, STDIN_FILENO, STDOUT_FILENO, piped_command.background); } BAN::Vector exit_codes(piped_command.commands.size(), 0); @@ -831,7 +843,7 @@ static int execute_piped_commands(const PipedCommand& piped_command) exit_codes[i] = builtin_ret.value(); else { - pid_t pid = execute_command_no_wait(piped_command.commands[i], next_stdin, pipefd[1], pgrp); + const pid_t pid = execute_command_no_wait(piped_command.commands[i], next_stdin, pipefd[1], pgrp, piped_command.background); processes[i] = pid; if (pgrp == 0) pgrp = pid; @@ -844,6 +856,9 @@ static int execute_piped_commands(const PipedCommand& piped_command) next_stdin = pipefd[0]; } + if (piped_command.background) + return 0; + for (size_t i = 0; i < piped_command.commands.size(); i++) { if (processes[i] == -1) @@ -883,8 +898,18 @@ static int parse_and_execute_command(BAN::StringView command) tcsetattr(0, TCSANOW, &old_termios); last_return = 0; - for (const auto& [expression, condition] : command_list.commands) + + for (size_t i = 0; i < command_list.commands.size(); i++) { + const auto& [expression, condition] = command_list.commands[i]; + + const auto parsed_command = parse_piped_command(expression); + if (parsed_command.background && i + 1 < command_list.commands.size() && command_list.commands[i + 1].condition != CommandList::Condition::Always) + { + printf("invalid background command with conditional execution\n"); + break; + } + bool should_run = false; switch (condition) { @@ -902,7 +927,9 @@ static int parse_and_execute_command(BAN::StringView command) if (!should_run) continue; - last_return = execute_piped_commands(parse_piped_command(expression)); + int return_value = execute_piped_commands(parsed_command); + if (!parsed_command.background) + last_return = return_value; } tcsetattr(0, TCSANOW, &new_termios);