Core data structures and constants. More...

#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>

Classes
struct	Command
	Represents one command with arguments and redirections. More...

struct	Line
	Represents a full line of user input. More...

Macros
#define	MAX_CMDLINE 2001
	Maximum command line length including null terminator.

#define	MAX_TOKENS 2000
	Upper bound on number of tokens from max line length.

#define	MAX_TOKEN_LEN 30
	Maximum length of a single token.

#define	MAX_ARGS 64
	Reasonable cap on arguments per command.

#define	MAX_JOBS 20
	Maximum number of jobs to track.

#define	FILE_CREATE_MODE (S_IRUSR \| S_IWUSR \| S_IRGRP \| S_IWGRP \| S_IROTH)
	File creation mode.

Typedefs
typedef struct Command	Command
	Represents one command with arguments and redirections.

typedef struct Line	Line
	Represents a full line of user input.

Enumerations
enum	TokenKind { TK_WORD , TK_REDIR_IN , TK_REDIR_OUT , TK_REDIR_ERR , TK_PIPE , TK_AMP }
	Token kinds. More...

Functions
void	init_command (Command *cmd)
	Initialize a Command structure to NULL/0 values.

Variables
volatile sig_atomic_t	child_status_changed
	Flag indicating that a child process status has changed.

pid_t	foreground_pgid
	Process group ID of the current foreground process.

Detailed Description

Core data structures and constants.

This file contains the core data structures and constants used throughout the YASH shell implementation.

Typedef Documentation

typedef struct Command Command

Represents one command with arguments and redirections.

Invariants:

argv is always NULL-terminated.
argv[0] must exist for a valid command (cannot be empty).
At most one of each redirection (in_file, out_file, err_file) may be set.
Redirection fields are either a filename string or NULL.
background == 1 is only valid if the containing Line.is_pipeline == 0.
argv pointers reference the tokenized input buffer, which must outlive parsing and execution.

typedef struct Line Line

Represents a full line of user input.

Invariants:

If is_pipeline == 0: left is valid, right is unused.
If is_pipeline == 1: both left and right must have argv[0].
Background execution (&) is invalid when is_pipeline == 1.
original always contains the raw command line string as typed, including & if present.

Token kinds.

void init_command ( Command * cmd )

Initialize a Command structure to NULL/0 values.

Parameters

cmd	Pointer to Command structure to initialize