MyShell

Author: Ze Sheng (Owen Sanazas)

Source Files

• myshell.c
• shell-behaviour.c
• shell-behaviour.h
• job.c
• job.h
• utils.c
• utils.h

Progress

• ✓ - Finished
• O - In progess
• ? - Have problem
• blank - Not started

Section	State
ctrl + c	✓
ctrl + z	✓
Non-interactive mode	✓
Command parser	✓
File redirection	✓
multi-lvl pipeline	✓
job struct	✓
jobList Linkedlist	✓
All job helper funcs	✓
Bultin cmd: jobs	✓
Bultin cmd: fg	✓
Bultin cmd: bg	✓
Memory leaks check	✓
Invalid R/W check	✓
Zombie processes check	✓
Foreground check	✓
Background check	✓

Overview of work accomplished

• This shell can be run in the non-interactive mode successfully.
• All commands that are not job control builtins commands are handled by pipe. The standard input/output will be redirected and combining redirection is also supported.
• We manage each job in a JobNode struct and use a linked list struct JobList to store all background jobs.

  // Job Node
  typedef struct JobNode {
      int pgid;                           // process group id of the current running job
      enum JobStatus status;              // Job status
      struct parsed_command *command;     // job's command
      struct JobNode *prev;               // Prev job pointer
      struct JobNode *next;               // Next job pointer
      int jobId;                          // Job priority
  }JobNode;
  
  
  // Linked-list structure to manage jobs
  typedef struct JobList {
      JobNode *head;
      JobNode *tail;
      int jobCount;
  }JobList;
  

• Background processes (if existed) will be polled at the beginning of each loop of the shell.
• The jobs can be managed through job control builtins (fg, bg, jobs).
• The status of the jobs can be reported correctly.
• Ctrl-C, Ctrl-D, Ctrl-Z, and other signal are handled correctly.