Explanation of data structs

struct

typedef struct s_shell { t_env *env_lst; t_token *token; t_cmd *cmd; int prev_exit; int exit; // more to add } t_shell;

typedef struct s_cmd { char **cmd; char *path; t_redir *redir; struct s_cmd *next; } t_cmd;

typedef struct s_redir { t_type type; char *file; int fd; struct s_redir *next;

} t_redir;

explain

In t_shell shell:

1. *cmd is the head node of all the commands
   • if there are more than one pipes, there will be more commands. aka cmd->next will be how to get to the next command.
2. exit is to record the current process's exit code.
   • After the whole execusion is done, update the prev_exit = exit
3. *env_lst is a linked list. for execve(), we need a char **enviorn

In t_cmd cmd:

1. char **cmd: cmd[0] is the command, the rest is the options of the command.
2. char *path: is the command's execution path, like /usr/bin/echo for the usage of execve();
3. t_redir *redir:
   1. t_type type: IN, OUT, HEREDOC, APPEND
   2. char *file: the address string of the file directory.
   3. int fd: the fd return by open(file);
   4. next: next redir node.
   • ATTENTION: During Execution, dup_file, redir need to be checked with one will be replaced with pipes[i][0] and pipes[i][1];

The functions explain

pipe.c

1. create_pipes
2. create_process
   • run child process
     • builtin commd
     • execve commd
   • close parent pipes
3. wait for process finish and update shell->exit.

More functions to work

1. in create_process
   • create_environ()
   • dup_files()
     • redir_fd()_
   • execve_cmd()
   • intergrate builtin functions.
2. wait for process finish
   • set correct exit code.
3. system error handling
4. signal handling.