sh: Make it much more versatile
This commit implements: Argument matching, to show help and version Support for running scripts Support for parsing and running commands (via -c) This is the first step to implementing the system() libc function.
This commit is contained in:
parent
e58aa361c8
commit
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179
apps/src/sh.c
179
apps/src/sh.c
@ -16,7 +16,8 @@ typedef struct
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char* buffer;
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size_t size;
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size_t capacity;
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} command;
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int interactive;
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} command_t;
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char** split_command_into_argv(const char* cmd)
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{
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@ -78,30 +79,19 @@ void shell_execvp(char* pathname, char* const argv[])
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void show_prompt()
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{
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if (!username)
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{
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struct passwd* user = getpwuid(getuid());
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if (!user)
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{
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if (errno) perror("getpwuid");
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username = "??";
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}
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else { username = user->pw_name; }
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atexit(endpwent);
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}
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if (WEXITSTATUS(status)) { printf("%d [%s]> ", WEXITSTATUS(status), username); }
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else
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printf("[%s]> ", username);
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}
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int command_matches(command* cmd, const char* string)
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int command_matches(command_t* cmd, const char* string)
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{
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if (cmd->size <= strlen(string)) // cmd->size includes null terminator
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return 0;
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return strncmp(cmd->buffer, string, strlen(string)) == 0;
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}
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int command_matches_exactly(command* cmd, const char* string)
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int command_matches_exactly(command_t* cmd, const char* string)
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{
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if (cmd->size <= strlen(string)) // cmd->size includes null terminator
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return 0;
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@ -109,7 +99,7 @@ int command_matches_exactly(command* cmd, const char* string)
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return strncmp(cmd->buffer, string, strlen(string)) == 0;
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}
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int command_match_builtins(command* cmd)
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int command_match_builtins(command_t* cmd)
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{
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if (command_matches(cmd, "exit ")) { exit(atoi(cmd->buffer + 5)); }
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if (command_matches_exactly(cmd, "exit")) { exit(0); }
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@ -126,7 +116,7 @@ int command_match_builtins(command* cmd)
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return 0;
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}
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void command_expand(command* cmd, long new_capacity)
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void command_expand(command_t* cmd, long new_capacity)
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{
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char* buffer = realloc(cmd->buffer, new_capacity);
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if (!buffer)
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@ -138,38 +128,46 @@ void command_expand(command* cmd, long new_capacity)
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cmd->capacity = new_capacity;
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}
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void command_push(command* cmd, char c)
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void command_push(command_t* cmd, char c)
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{
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if (cmd->size == cmd->capacity) command_expand(cmd, cmd->capacity + 8);
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cmd->buffer[cmd->size] = c;
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cmd->size++;
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}
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void command_pop(command* cmd)
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void command_pop(command_t* cmd)
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{
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cmd->size--;
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}
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void command_init(command* cmd)
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void command_init(command_t* cmd)
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{
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cmd->buffer = malloc(5);
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cmd->capacity = 5;
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cmd->size = 0;
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}
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void command_clear(command* cmd)
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void command_clear(command_t* cmd)
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{
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free(cmd->buffer);
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return command_init(cmd);
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}
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void command_execute(command* cmd)
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void process_execute_command(const char* command)
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{
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char** argv = split_command_into_argv(command);
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shell_execvp(argv[0], argv);
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perror(argv[0]);
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exit(127);
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}
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void command_execute(command_t* cmd)
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{
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command_push(cmd, '\0');
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if (command_match_builtins(cmd))
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{
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command_clear(cmd);
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show_prompt();
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if (cmd->interactive) show_prompt();
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return;
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}
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pid_t child = fork();
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@ -177,60 +175,54 @@ void command_execute(command* cmd)
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{
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perror("fork");
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command_clear(cmd);
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show_prompt();
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if (cmd->interactive) show_prompt();
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return;
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}
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if (child == 0)
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{
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char** argv = split_command_into_argv(cmd->buffer);
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shell_execvp(argv[0], argv);
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perror(argv[0]);
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exit(127);
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}
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if (child == 0) process_execute_command(cmd->buffer);
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pid_t result = waitpid(child, &status, 0);
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if (result < 0)
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{
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perror("waitpid");
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command_clear(cmd);
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show_prompt();
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if (cmd->interactive) show_prompt();
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return;
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}
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int exit_status = WEXITSTATUS(status);
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if (exit_status == -2 || exit_status == -3) printf("(PID %ld) Segmentation fault\n", result);
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if (exit_status == -1) printf("(PID %ld) Aborted\n", result);
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command_clear(cmd);
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show_prompt();
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if (cmd->interactive) show_prompt();
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}
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void command_concat_char(command* cmd, char c)
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void command_concat_char(command_t* cmd, char c)
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{
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if (c == '\b')
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{
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if (cmd->size != 0)
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{
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putchar(c);
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if (cmd->interactive) putchar(c);
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command_pop(cmd);
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}
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}
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else if (c == '\n')
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{
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putchar(c);
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if (cmd->interactive) putchar(c);
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if (cmd->size == 0)
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{
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status = 0;
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show_prompt();
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if (cmd->interactive) show_prompt();
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}
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else
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command_execute(cmd);
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}
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else
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{
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putchar(c);
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if (cmd->interactive) putchar(c);
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command_push(cmd, c);
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}
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}
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void command_concat(command* cmd, const char* str)
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void command_concat(command_t* cmd, const char* str)
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{
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while (*str)
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{
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@ -239,13 +231,15 @@ void command_concat(command* cmd, const char* str)
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}
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}
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int main()
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void shell_interactive()
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{
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show_prompt();
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command shell_command;
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command_t shell_command;
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command_init(&shell_command);
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shell_command.interactive = 1;
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while (1)
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{
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int c = getchar();
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@ -254,11 +248,112 @@ int main()
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if (ferror(stdin))
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{
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perror("getchar");
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return 1;
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exit(EXIT_FAILURE);
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}
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if (feof(stdin)) return 0;
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if (feof(stdin)) exit(EXIT_SUCCESS);
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assert(false); // we should never get here
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}
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command_concat_char(&shell_command, (char)c);
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}
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}
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void shell_read_from_file(const char* pathname)
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{
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FILE* fp = fopen(pathname, "r");
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if (!fp)
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{
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perror("sh");
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exit(EXIT_FAILURE);
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}
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command_t file_command;
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command_init(&file_command);
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file_command.interactive = 0;
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char buffer[BUFSIZ];
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while (fgets(buffer, BUFSIZ, fp))
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{
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command_concat(&file_command, buffer);
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if (feof(fp)) break;
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}
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if (file_command.size > 0) // last line of file, does not end with newline
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{
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command_execute(&file_command);
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}
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fclose(fp);
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}
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void shell_execute_command(const char* command)
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{
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command_t cmd;
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cmd.buffer = strdup(command);
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cmd.size = strlen(command) + 1;
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if (command_match_builtins(&cmd)) return;
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command_clear(&cmd);
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process_execute_command(command);
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}
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void fetch_username()
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{
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struct passwd* user = getpwuid(getuid());
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if (!user)
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{
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perror("getpwuid");
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exit(EXIT_FAILURE);
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}
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username = user->pw_name;
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endpwent();
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}
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int main(int argc, char** argv)
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{
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fetch_username();
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if (argc == 1) shell_interactive();
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else if (argc == 2)
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{
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if (!strcmp(argv[1], "-v") || !strcmp(argv[1], "--version"))
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{
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puts("Luna sh version 0.1"); // FIXME: Store the version somewhere, or use the kernel's version.
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return 0;
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}
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if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help"))
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{
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printf("To use interactively: %s\n", argv[0]);
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printf("To run a script: %s [script-name]\n", argv[0]);
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printf("To get help: %s --help\n", argv[0]);
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printf("To show the version: %s --version\n", argv[0]);
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printf("To run a command: %s -c [command]\n", argv[0]);
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return 0;
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}
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if (!strcmp(argv[1], "-c") || !strcmp(argv[1], "--command"))
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{
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fprintf(stderr, "Usage: %s %s [command]\n", argv[0], argv[1]);
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fprintf(stderr, "Use the --help flag for more help.\n");
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return 1;
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}
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shell_read_from_file(argv[1]);
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}
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else if (argc == 3)
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{
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if (!strcmp(argv[1], "-c") || !strcmp(argv[1], "--command")) shell_execute_command(argv[2]);
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else
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{
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fprintf(stderr, "%s: too many arguments\n", argv[0]);
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fprintf(stderr, "Use the --help flag for more help.\n");
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return 1;
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}
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}
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else
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{
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fprintf(stderr, "%s: too many arguments\n", argv[0]);
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fprintf(stderr, "Use the --help flag for more help.\n");
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return 1;
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}
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}
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