diff options
Diffstat (limited to 'shell.c')
| -rw-r--r-- | shell.c | 401 |
1 files changed, 345 insertions, 56 deletions
@@ -22,6 +22,7 @@ MAKE_QUEUE_PUSH(c_queue, cmdline, char**) MAKE_QUEUE_PUSH(p_queue, pid, int) enum modes { word_separation, whole_word }; +volatile sig_atomic_t last_execution_status = 0; static void change_terminal_settings(struct termios *cur_terminal_settings, struct termios *save_terminal_settings) @@ -49,11 +50,17 @@ static void show_invitation() static void handler(int signal) { int save_errno = errno; - int pid; + int pid, result; if(signal == SIGCHLD) { do { - pid = wait4(-1, NULL, WNOHANG, NULL); + pid = wait4(-1, &result, WNOHANG, NULL); + if(pid > 0) { + if(WIFEXITED(result)) + last_execution_status = WEXITSTATUS(result) == 0 ? 0 : 1; + else + last_execution_status = 1; + } } while(pid > 0); } errno = save_errno; @@ -71,12 +78,17 @@ static void init_params(struct param_type *params, enum modes *current_mode) params->streams.input_stream = NULL; params->streams.output_stream = NULL; params->streams.output_stream_to_append = NULL; - /* 0 - success, 1 - error */ - params->last_execution_status = 0; params->pipeline = 0; params->new_readline = 1; params->general_pgid = -1; + params->general_pipe_pgid = -1; + params->general_subshell_pgid = -1; + params->subshell = 0; + params->background_process = 0; + params->fd_read_for_channel = -1; + params->fd_read_for_subshell = -1; *current_mode = word_separation; + last_execution_status = 0; } static void clear_filename(struct param_type *params) @@ -105,6 +117,10 @@ static void reset_params(struct param_type *params, readline_reset_array(readline); clear_filename(params); init_params(params, current_mode); + if(params->fd_read_for_channel != -1) + close(params->fd_read_for_channel); + if(params->fd_read_for_subshell != -1) + close(params->fd_read_for_subshell); } static void prepare_for_next_command_on_line(struct param_type *params, @@ -149,6 +165,8 @@ static const char* error_code_to_token(int error_code) case err_empty_command: return "empty command"; case err_extra_chars_after_filename: return "extra chars after filename"; case err_odd_double_quotes: return "odd number of double quotes"; + case err_missing_closing_bracket: return "missing closing bracket"; + case err_repeated_background_ch: return "repeated &"; } return NULL; } @@ -160,24 +178,28 @@ void error_identification(const struct param_type *params) static int special_token_handling(struct w_queue *word_chain, struct c_queue *cmdlines, - struct dynamic_array *tmp_word, int ch, + struct dynamic_array *tmp_word, int *ch, struct param_type *params, struct readline_type *readline) { return - stream_redirect_tokens(word_chain, tmp_word, ch, params, readline) ? + stream_redirect_tokens(word_chain, tmp_word, *ch, params, readline) ? 1 : special_tokens(word_chain, cmdlines, tmp_word, ch, params, readline); } static void wait_for_process_to_complete(struct p_queue *pid_store) { - int total_process_counter, current_process_counter, wait_pid; + int total_process_counter, current_process_counter, wait_pid, result; total_process_counter = p_queue_get_process_quantity(pid_store); current_process_counter = 0; do { - wait_pid = wait(NULL); + wait_pid = wait(&result); + if(WIFEXITED(result)) + last_execution_status = WEXITSTATUS(result) == 0 ? 0 : 1; + else + last_execution_status = 1; if(p_queue_find_pid(pid_store, wait_pid)) ++current_process_counter; } while(total_process_counter != current_process_counter); @@ -202,23 +224,34 @@ static void close_files(int input_fd, int output_fd) close(output_fd); } +static int get_true_terminal_fd() +{ + if(isatty(0)) + return 0; + else if(isatty(1)) + return 1; + else return 2; +} + static void postprocessing(struct w_queue *word_chain, struct c_queue *cmdlines, struct p_queue *pid_store, struct param_type *params, int input_fd, int output_fd) { + int terminal_fd; clean_up_memory(word_chain, cmdlines, params); close_files(input_fd, output_fd); - if(params->tokens != '&') { + if(!params->background_process) { wait_for_process_to_complete(pid_store); signal(SIGTTOU, SIG_IGN); - tcsetpgrp(0, getpid()); + terminal_fd = get_true_terminal_fd(); + tcsetpgrp(terminal_fd, getpid()); } p_queue_clear(pid_store); } static void set_signal_disposition(struct param_type *params) { - if(params->tokens == '&') + if(params->background_process) /* zombie process termination on signal */ signal(SIGCHLD, handler); else @@ -249,58 +282,146 @@ int is_stream_redirection_set(const struct param_type *params) params->streams.output_stream_to_append; } +static void identify_general_pipe_pgid(struct param_type *params, int pid) +{ + int terminal_fd; + if(params->general_pipe_pgid == -1) + params->general_pipe_pgid = pid; + if(!params->background_process) { + /* foreground group */ + terminal_fd = get_true_terminal_fd(); + signal(SIGTTOU, SIG_IGN); + tcsetpgrp(terminal_fd, params->general_pipe_pgid); + } +} + static void identify_general_pgid(struct param_type *params, int pid) { + int terminal_fd; if(params->general_pgid == -1) params->general_pgid = pid; - if(params->tokens != '&') + if(!params->background_process) { /* foreground group */ - tcsetpgrp(0, params->general_pgid); + terminal_fd = get_true_terminal_fd(); + signal(SIGTTOU, SIG_IGN); + tcsetpgrp(terminal_fd, params->general_pgid); + } +} + +static int find_subshell_after_pipe(struct readline_type *readline) +{ + int i; + for(i = readline->considered_index; i <= readline->last_element_index; ++i) { + if(readline->arr[i] == ' ') + continue; + if(readline->arr[i] == '(') + return 1; + break; + } + return 0; +} + +static int is_background_command(struct readline_type *readline) +{ + int i; + for(i = readline->considered_index; i <= readline->last_element_index; ++i){ + if(readline->arr[i] == '&' && readline->arr[i+1] != '&') + return 1; + else if(readline->arr[i] == '&' && readline->arr[i+1] == '&') + ++i; + } + return 0; } static void make_pipeline(struct w_queue *word_chain, struct c_queue *cmdlines, struct param_type *params, + struct readline_type *readline, int input_fd, int output_fd) { struct p_queue pid_store; p_queue_init(&pid_store); char **cmdline = NULL; int fd[2]; - int save_read_fd, pid; + int subshell_fd[2]; + int save_read_fd, pid, subshell_after; - pipe(fd); + subshell_after = find_subshell_after_pipe(readline); cmdline = c_queue_pop(cmdlines); + + if(!c_queue_is_empty(cmdlines)) + pipe(fd); + set_signal_disposition(params); + +#if 0 + if(params->fd_pipe_rd != -1) + /* set foreground group by subshell process */ + identify_general_pgid(params, params->general_pgid); +#endif + + if(c_queue_is_empty(cmdlines) && subshell_after) + pipe(subshell_fd); + pid = fork(); +#if 0 /* parent process */ if(pid) identify_general_pgid(params, pid); +#endif + if(pid) { + /* else set foreground group by first pipe process */ + if(params->general_pipe_pgid == -1) + identify_general_pipe_pgid(params, pid); + } if(pid == 0) { - close(fd[0]); - dup2(fd[1], 1); - close(fd[1]); - if(is_stream_redirection_set(params)) + if(params->fd_read_for_channel != -1) { + dup2(params->fd_read_for_channel, 0); + close(params->fd_read_for_channel); + } + if(!c_queue_is_empty(cmdlines)) { + close(fd[0]); + dup2(fd[1], 1); + close(fd[1]); + } else if(subshell_after) { + close(subshell_fd[0]); + dup2(subshell_fd[1], 1); + close(subshell_fd[1]); + } + if(is_stream_redirection_set(params)) { change_streams(input_fd, output_fd, 1, 1); + if(params->fd_read_for_channel != -1 && c_queue_is_empty(cmdlines)) + change_streams(input_fd, output_fd, 1, 0); + } /* change pgid */ - setpgid(getpid(), params->general_pgid == -1 ? - getpid() : params->general_pgid); + setpgid(getpid(), params->general_pipe_pgid == -1 ? getpid() : + params->general_pipe_pgid); execvp(cmdline[0], cmdline); perror(cmdline[0]); exit(1); } - - close(fd[1]); p_queue_push(&pid_store, pid); + if(params->fd_read_for_channel != -1) + close(params->fd_read_for_channel); + + if(subshell_after && c_queue_is_empty(cmdlines)) { + params->fd_read_for_subshell = subshell_fd[0]; + close(subshell_fd[1]); + } + + if(!c_queue_is_empty(cmdlines)) + close(fd[1]); while(!c_queue_is_empty(cmdlines)) { cmdline = c_queue_pop(cmdlines); /* if not last process in pipeline*/ - if(!c_queue_is_empty(cmdlines)) { + if(!c_queue_is_empty(cmdlines)){ save_read_fd = fd[0]; pipe(fd); - } + } else if(subshell_after) + pipe(subshell_fd); + pid = fork(); if(pid == 0) { if(!c_queue_is_empty(cmdlines)) { @@ -314,13 +435,17 @@ static void make_pipeline(struct w_queue *word_chain, struct c_queue *cmdlines, close(fd[0]); } /* for last process in pipeline */ - if(c_queue_is_empty(cmdlines)) + if(c_queue_is_empty(cmdlines)) { if(is_stream_redirection_set(params)) change_streams(input_fd, output_fd, 1, 0); - + if(subshell_after) { + close(subshell_fd[0]); + dup2(subshell_fd[1], 1); + close(subshell_fd[1]); + } + } /* change pgid */ - setpgid(getpid(), params->general_pgid); - + setpgid(getpid(), params->general_pipe_pgid); execvp(cmdline[0], cmdline); perror(cmdline[0]); exit(1); @@ -328,12 +453,23 @@ static void make_pipeline(struct w_queue *word_chain, struct c_queue *cmdlines, if(!c_queue_is_empty(cmdlines)) { close(save_read_fd); close(fd[1]); - } else + } else { close(fd[0]); + if(subshell_after) + close(subshell_fd[1]); + } p_queue_push(&pid_store, pid); } + if(subshell_after) + params->fd_read_for_subshell = subshell_fd[0]; + else + params->fd_read_for_subshell = -1; postprocessing(word_chain, cmdlines, &pid_store, params, input_fd, output_fd); +#if 0 + if(!subshell_after) + params->general_pgid = -1; +#endif } static void open_files(const struct param_type *params, int *input_fd, @@ -380,7 +516,8 @@ static void change_directory(char **cmdline) static void run_external_program(struct w_queue *word_chain, struct c_queue *cmdlines, - struct param_type *params) + struct param_type *params, + struct readline_type *readline) { int pid, input_fd, output_fd; struct p_queue pid_store; @@ -389,6 +526,11 @@ static void run_external_program(struct w_queue *word_chain, input_fd = 0; output_fd = 0; + if(is_background_command(readline)) + params->background_process = 1; + else + params->background_process = 0; + if(is_stream_redirection_set(params)) open_files(params, &input_fd, &output_fd); @@ -397,7 +539,8 @@ static void run_external_program(struct w_queue *word_chain, return; } if(params->pipeline) { - make_pipeline(word_chain, cmdlines, params, input_fd, output_fd); + make_pipeline(word_chain, cmdlines, params, readline, + input_fd, output_fd); return; } cmdline = c_queue_pop(cmdlines); @@ -410,19 +553,29 @@ static void run_external_program(struct w_queue *word_chain, perror("fork error"); exit(1); } +#if 0 /* parent process */ if(pid) - identify_general_pgid(params, pid); + identify_general_pgid(params, getpid()); +#endif + /* child process */ if(pid == 0) { if(is_stream_redirection_set(params)) change_streams(input_fd, output_fd, 0, 0); - /* change pgid */ - setpgid(getpid(), params->general_pgid == -1 ? - getpid() : params->general_pgid); + if(params->fd_read_for_channel != -1) { + dup2(params->fd_read_for_channel, 0); + close(params->fd_read_for_channel); + } + /* set foreground process */ + if(params->subshell && params->general_pgid != -1) + setpgid(getpid(), params->general_pgid); + else { + identify_general_pgid(params, getpid()); + setpgid(getpid(), getpid()); + } execvp(cmdline[0], cmdline); - params->last_execution_status = 1; perror(cmdline[0]); exit(1); } @@ -430,6 +583,11 @@ static void run_external_program(struct w_queue *word_chain, p_queue_push(&pid_store, pid); postprocessing(word_chain, cmdlines, &pid_store, params, input_fd, output_fd); + /* ??? */ +#if 0 + if(!params->subshell) + params->general_pgid = -1; +#endif } } @@ -500,10 +658,14 @@ static void generate_readline(struct readline_type *readline) { struct termios cur_terminal_settings, save_terminal_settings; enum keys found_key = none; - int match_result; + int match_result, terminal_fd; char ch; change_terminal_settings(&cur_terminal_settings, &save_terminal_settings); + /* return foreground group by main process */ + terminal_fd = get_true_terminal_fd(); + signal(SIGTTOU, SIG_IGN); + tcsetpgrp(terminal_fd, getpid()); while((ch = getchar()) && !readline_termination_condition(ch, readline)) { if(ch == tab) { @@ -589,27 +751,41 @@ static void command_processing(struct param_type *params, } else if(params->empty_word_flag || params->is_word) add_word(word_chain, tmp_word, params); - if((params->tokens == and || params->tokens == or) && - params->last_execution_status == 1) { - /* ??? */ - fprintf(stderr, "cannot be performed\n"); - return; + if(word_chain->first == NULL && cmdlines->first == NULL) { + /* if not ending subshell */ + if(params->tokens != '(') + params->wrong_command = err_empty_command; + goto clean; } - - if(word_chain->first == NULL) { - params->wrong_command = err_empty_command; +#if 0 + if((ch == new_line || ch == end_subshell) && + ((params->tokens == and && last_execution_status == 1) || + (params->tokens == or && last_execution_status == 0))) { + if(ch == end_subshell && params->subshell) + exit(1); + params->wrong_command = err_set_failure; goto clean; } +#endif + /* not subshell process; was &&/|| command\n */ + if(ch == new_line && + ((params->tokens == and && last_execution_status == 1) || + (params->tokens == or && last_execution_status == 0))) + goto clean; - cmdline = create_cmdline(word_chain, w_queue_get_word_count(word_chain)); - c_queue_push(cmdlines, cmdline); - run_external_program(word_chain, cmdlines, params); + if(word_chain->first != NULL) { + cmdline = create_cmdline(word_chain, w_queue_get_word_count(word_chain)); + c_queue_push(cmdlines, cmdline); + } + run_external_program(word_chain, cmdlines, params, readline); clean: error_identification(params); + if(params->tokens == end_subshell && params->subshell) + exit(last_execution_status); last_token = params->tokens; - if(last_token == '&' || last_token == 0 || ch == new_line) { + if(last_token == 0 || ch == new_line) { reset_params(params, current_mode, word_chain, cmdlines, tmp_word, readline); show_invitation(); @@ -619,6 +795,99 @@ clean: tmp_word); } +/* searching for the paired closed bracket too */ +static int find_pipeline_after_subshell(struct readline_type *readline, + struct param_type *params) +{ + int i; + for(i = readline->considered_index; i <= readline->last_element_index && + readline->arr[i] != ')'; ++i) + {} + + if(i == readline->last_element_index+1) { + params->wrong_command = err_missing_closing_bracket; + return 0; + } + ++i; + while(i <= readline->last_element_index) { + if(readline->arr[i] == ' ') { + ++i; + continue; + } + break; + } + if(readline->arr[i] == '|') + return 1; + else + return 0; +} + +static void readline_idx_after_subshell(struct readline_type *readline, + struct param_type *params) +{ + int i; + for(i = readline->considered_index; i <= readline->last_element_index && + readline->arr[i] != ')'; ++i) + {} + + if(i == readline->last_element_index + 1) { + params->wrong_command = err_missing_closing_bracket; + return; + } + + ++i; + /* skip whitespace symbols */ + for( ; i <= readline->last_element_index && readline->arr[i] == ' '; ++i) + {} + readline->considered_index = i; +} + +static void make_subshell(struct readline_type *readline, + struct param_type *params) +{ + int fd[2]; + int pid, pipeline_after, pipeline_before; + + pipeline_after = 0; + + pipeline_after = find_pipeline_after_subshell(readline, params); + pipeline_before = params->fd_read_for_subshell != -1 ? 1 : 0; + + if(pipeline_after) { + pipe(fd); + params->fd_read_for_channel = fd[0]; + } + + pid = fork(); + /* child */ + if(pid == 0) { + params->subshell = 1; + params->pipeline = 0; + if(pipeline_after) { + identify_general_pipe_pgid(params, getpid()); + params->general_pgid = getpid(); + setpgid(getpid(), params->general_pipe_pgid); + close(fd[0]); + dup2(fd[1], 1); + close(fd[1]); + } + if(pipeline_before) { + dup2(params->fd_read_for_subshell, 0); + close(params->fd_read_for_subshell); + params->general_pgid = params->general_pipe_pgid; + setpgid(getpid(), params->general_pipe_pgid); + } + /* parent */ + } else { + sleep(1); + if(pipeline_after) { + close(fd[1]); + params->general_pipe_pgid = pid; + } + readline_idx_after_subshell(readline, params); + } +} + static void word_separation_processing(int ch, struct param_type *params, enum modes *current_mode, struct w_queue *word_chain, @@ -644,15 +913,22 @@ static void word_separation_processing(int ch, struct param_type *params, params->escape_sequences = 1; return; } - if(special_token_handling(word_chain, cmdlines, tmp_word, ch, params, + if(special_token_handling(word_chain, cmdlines, tmp_word, &ch, params, readline)) { - if(command_execution_condition(params)) + if(command_execution_condition(params, readline)) command_processing(params, current_mode, word_chain, cmdlines, tmp_word, readline, ch); + if(params->tokens == start_subshell) + make_subshell(readline, params); return; } if(params->wrong_command) { error_identification(params); + + /* subshell termination failed; failure with (&&, ||) too */ + if(params->subshell) + exit(1); + clean_input_buffer(); reset_params(params, current_mode, word_chain, cmdlines, tmp_word, readline); @@ -660,9 +936,12 @@ static void word_separation_processing(int ch, struct param_type *params, return; } if(check_separation(ch, *params)) { - if(excessive_words(ch, params)) { + if(excessive_words(ch, params, readline)) { error_identification(params); clean_input_buffer(); + /* subshell termination failed */ + if(params->subshell) + exit(1); reset_params(params, current_mode, word_chain, cmdlines, tmp_word, readline); show_invitation(); @@ -731,6 +1010,7 @@ int main() dynarr_create_array(&tmp_word); readline_create_array(&readline); init_params(¶ms, ¤t_mode); + signal(SIGCHLD, handler); show_invitation(); generate_readline(&readline); @@ -747,9 +1027,18 @@ int main() else if(current_mode == word_separation) { word_separation_processing(ch, ¶ms, ¤t_mode, &word_chain, &cmdlines, &tmp_word, &readline); - /* double token was found */ - if(readline.considered_index != i) - ++i; + if(params.tokens == start_subshell && !params.subshell) { + i = readline.considered_index; + continue; + } + /* + * either a double token was found + * or the subshell part was skipped + */ + if(readline.considered_index != i) { + i = readline.considered_index; + continue; + } } else if(current_mode == whole_word) whole_word_processing(ch, ¶ms, ¤t_mode, &word_chain, |