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-rw-r--r--shlab-handout/tsh.c509
1 files changed, 0 insertions, 509 deletions
diff --git a/shlab-handout/tsh.c b/shlab-handout/tsh.c
deleted file mode 100644
index 7c2ea8d..0000000
--- a/shlab-handout/tsh.c
+++ /dev/null
@@ -1,509 +0,0 @@
-/*
- * tsh - A tiny shell program with job control
- *
- * <Put your name and login ID here>
- */
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <ctype.h>
-#include <signal.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <errno.h>
-
-/* Misc manifest constants */
-#define MAXLINE 1024 /* max line size */
-#define MAXARGS 128 /* max args on a command line */
-#define MAXJOBS 16 /* max jobs at any point in time */
-#define MAXJID 1<<16 /* max job ID */
-
-/* Job states */
-#define UNDEF 0 /* undefined */
-#define FG 1 /* running in foreground */
-#define BG 2 /* running in background */
-#define ST 3 /* stopped */
-
-/*
- * Jobs states: FG (foreground), BG (background), ST (stopped)
- * Job state transitions and enabling actions:
- * FG -> ST : ctrl-z
- * ST -> FG : fg command
- * ST -> BG : bg command
- * BG -> FG : fg command
- * At most 1 job can be in the FG state.
- */
-
-/* Global variables */
-extern char **environ; /* defined in libc */
-char prompt[] = "tsh> "; /* command line prompt (DO NOT CHANGE) */
-int verbose = 0; /* if true, print additional output */
-int nextjid = 1; /* next job ID to allocate */
-char sbuf[MAXLINE]; /* for composing sprintf messages */
-
-struct job_t { /* The job struct */
- pid_t pid; /* job PID */
- int jid; /* job ID [1, 2, ...] */
- int state; /* UNDEF, BG, FG, or ST */
- char cmdline[MAXLINE]; /* command line */
-};
-struct job_t jobs[MAXJOBS]; /* The job list */
-/* End global variables */
-
-
-/* Function prototypes */
-
-/* Here are the functions that you will implement */
-void eval(char *cmdline);
-int builtin_cmd(char **argv);
-void do_bgfg(char **argv);
-void waitfg(pid_t pid);
-
-void sigchld_handler(int sig);
-void sigtstp_handler(int sig);
-void sigint_handler(int sig);
-
-/* Here are helper routines that we've provided for you */
-int parseline(const char *cmdline, char **argv);
-void sigquit_handler(int sig);
-
-void clearjob(struct job_t *job);
-void initjobs(struct job_t *jobs);
-int maxjid(struct job_t *jobs);
-int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline);
-int deletejob(struct job_t *jobs, pid_t pid);
-pid_t fgpid(struct job_t *jobs);
-struct job_t *getjobpid(struct job_t *jobs, pid_t pid);
-struct job_t *getjobjid(struct job_t *jobs, int jid);
-int pid2jid(pid_t pid);
-void listjobs(struct job_t *jobs);
-
-void usage(void);
-void unix_error(char *msg);
-void app_error(char *msg);
-typedef void handler_t(int);
-handler_t *Signal(int signum, handler_t *handler);
-
-/*
- * main - The shell's main routine
- */
-int main(int argc, char **argv)
-{
- char c;
- char cmdline[MAXLINE];
- int emit_prompt = 1; /* emit prompt (default) */
-
- /* Redirect stderr to stdout (so that driver will get all output
- * on the pipe connected to stdout) */
- dup2(1, 2);
-
- /* Parse the command line */
- while ((c = getopt(argc, argv, "hvp")) != EOF) {
- switch (c) {
- case 'h': /* print help message */
- usage();
- break;
- case 'v': /* emit additional diagnostic info */
- verbose = 1;
- break;
- case 'p': /* don't print a prompt */
- emit_prompt = 0; /* handy for automatic testing */
- break;
- default:
- usage();
- }
- }
-
- /* Install the signal handlers */
-
- /* These are the ones you will need to implement */
- Signal(SIGINT, sigint_handler); /* ctrl-c */
- Signal(SIGTSTP, sigtstp_handler); /* ctrl-z */
- Signal(SIGCHLD, sigchld_handler); /* Terminated or stopped child */
-
- /* This one provides a clean way to kill the shell */
- Signal(SIGQUIT, sigquit_handler);
-
- /* Initialize the job list */
- initjobs(jobs);
-
- /* Execute the shell's read/eval loop */
- while (1) {
-
- /* Read command line */
- if (emit_prompt) {
- printf("%s", prompt);
- fflush(stdout);
- }
- if ((fgets(cmdline, MAXLINE, stdin) == NULL) && ferror(stdin))
- app_error("fgets error");
- if (feof(stdin)) { /* End of file (ctrl-d) */
- fflush(stdout);
- exit(0);
- }
-
- /* Evaluate the command line */
- eval(cmdline);
- fflush(stdout);
- fflush(stdout);
- }
-
- exit(0); /* control never reaches here */
-}
-
-/*
- * eval - Evaluate the command line that the user has just typed in
- *
- * If the user has requested a built-in command (quit, jobs, bg or fg)
- * then execute it immediately. Otherwise, fork a child process and
- * run the job in the context of the child. If the job is running in
- * the foreground, wait for it to terminate and then return. Note:
- * each child process must have a unique process group ID so that our
- * background children don't receive SIGINT (SIGTSTP) from the kernel
- * when we type ctrl-c (ctrl-z) at the keyboard.
-*/
-void eval(char *cmdline)
-{
- return;
-}
-
-/*
- * parseline - Parse the command line and build the argv array.
- *
- * Characters enclosed in single quotes are treated as a single
- * argument. Return true if the user has requested a BG job, false if
- * the user has requested a FG job.
- */
-int parseline(const char *cmdline, char **argv)
-{
- static char array[MAXLINE]; /* holds local copy of command line */
- char *buf = array; /* ptr that traverses command line */
- char *delim; /* points to first space delimiter */
- int argc; /* number of args */
- int bg; /* background job? */
-
- strcpy(buf, cmdline);
- buf[strlen(buf)-1] = ' '; /* replace trailing '\n' with space */
- while (*buf && (*buf == ' ')) /* ignore leading spaces */
- buf++;
-
- /* Build the argv list */
- argc = 0;
- if (*buf == '\'') {
- buf++;
- delim = strchr(buf, '\'');
- }
- else {
- delim = strchr(buf, ' ');
- }
-
- while (delim) {
- argv[argc++] = buf;
- *delim = '\0';
- buf = delim + 1;
- while (*buf && (*buf == ' ')) /* ignore spaces */
- buf++;
-
- if (*buf == '\'') {
- buf++;
- delim = strchr(buf, '\'');
- }
- else {
- delim = strchr(buf, ' ');
- }
- }
- argv[argc] = NULL;
-
- if (argc == 0) /* ignore blank line */
- return 1;
-
- /* should the job run in the background? */
- if ((bg = (*argv[argc-1] == '&')) != 0) {
- argv[--argc] = NULL;
- }
- return bg;
-}
-
-/*
- * builtin_cmd - If the user has typed a built-in command then execute
- * it immediately.
- */
-int builtin_cmd(char **argv)
-{
- return 0; /* not a builtin command */
-}
-
-/*
- * do_bgfg - Execute the builtin bg and fg commands
- */
-void do_bgfg(char **argv)
-{
- return;
-}
-
-/*
- * waitfg - Block until process pid is no longer the foreground process
- */
-void waitfg(pid_t pid)
-{
- return;
-}
-
-/*****************
- * Signal handlers
- *****************/
-
-/*
- * sigchld_handler - The kernel sends a SIGCHLD to the shell whenever
- * a child job terminates (becomes a zombie), or stops because it
- * received a SIGSTOP or SIGTSTP signal. The handler reaps all
- * available zombie children, but doesn't wait for any other
- * currently running children to terminate.
- */
-void sigchld_handler(int sig)
-{
- return;
-}
-
-/*
- * sigint_handler - The kernel sends a SIGINT to the shell whenver the
- * user types ctrl-c at the keyboard. Catch it and send it along
- * to the foreground job.
- */
-void sigint_handler(int sig)
-{
- return;
-}
-
-/*
- * sigtstp_handler - The kernel sends a SIGTSTP to the shell whenever
- * the user types ctrl-z at the keyboard. Catch it and suspend the
- * foreground job by sending it a SIGTSTP.
- */
-void sigtstp_handler(int sig)
-{
- return;
-}
-
-/*********************
- * End signal handlers
- *********************/
-
-/***********************************************
- * Helper routines that manipulate the job list
- **********************************************/
-
-/* clearjob - Clear the entries in a job struct */
-void clearjob(struct job_t *job) {
- job->pid = 0;
- job->jid = 0;
- job->state = UNDEF;
- job->cmdline[0] = '\0';
-}
-
-/* initjobs - Initialize the job list */
-void initjobs(struct job_t *jobs) {
- int i;
-
- for (i = 0; i < MAXJOBS; i++)
- clearjob(&jobs[i]);
-}
-
-/* maxjid - Returns largest allocated job ID */
-int maxjid(struct job_t *jobs)
-{
- int i, max=0;
-
- for (i = 0; i < MAXJOBS; i++)
- if (jobs[i].jid > max)
- max = jobs[i].jid;
- return max;
-}
-
-/* addjob - Add a job to the job list */
-int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline)
-{
- int i;
-
- if (pid < 1)
- return 0;
-
- for (i = 0; i < MAXJOBS; i++) {
- if (jobs[i].pid == 0) {
- jobs[i].pid = pid;
- jobs[i].state = state;
- jobs[i].jid = nextjid++;
- if (nextjid > MAXJOBS)
- nextjid = 1;
- strcpy(jobs[i].cmdline, cmdline);
- if(verbose){
- printf("Added job [%d] %d %s\n", jobs[i].jid, jobs[i].pid, jobs[i].cmdline);
- }
- return 1;
- }
- }
- printf("Tried to create too many jobs\n");
- return 0;
-}
-
-/* deletejob - Delete a job whose PID=pid from the job list */
-int deletejob(struct job_t *jobs, pid_t pid)
-{
- int i;
-
- if (pid < 1)
- return 0;
-
- for (i = 0; i < MAXJOBS; i++) {
- if (jobs[i].pid == pid) {
- clearjob(&jobs[i]);
- nextjid = maxjid(jobs)+1;
- return 1;
- }
- }
- return 0;
-}
-
-/* fgpid - Return PID of current foreground job, 0 if no such job */
-pid_t fgpid(struct job_t *jobs) {
- int i;
-
- for (i = 0; i < MAXJOBS; i++)
- if (jobs[i].state == FG)
- return jobs[i].pid;
- return 0;
-}
-
-/* getjobpid - Find a job (by PID) on the job list */
-struct job_t *getjobpid(struct job_t *jobs, pid_t pid) {
- int i;
-
- if (pid < 1)
- return NULL;
- for (i = 0; i < MAXJOBS; i++)
- if (jobs[i].pid == pid)
- return &jobs[i];
- return NULL;
-}
-
-/* getjobjid - Find a job (by JID) on the job list */
-struct job_t *getjobjid(struct job_t *jobs, int jid)
-{
- int i;
-
- if (jid < 1)
- return NULL;
- for (i = 0; i < MAXJOBS; i++)
- if (jobs[i].jid == jid)
- return &jobs[i];
- return NULL;
-}
-
-/* pid2jid - Map process ID to job ID */
-int pid2jid(pid_t pid)
-{
- int i;
-
- if (pid < 1)
- return 0;
- for (i = 0; i < MAXJOBS; i++)
- if (jobs[i].pid == pid) {
- return jobs[i].jid;
- }
- return 0;
-}
-
-/* listjobs - Print the job list */
-void listjobs(struct job_t *jobs)
-{
- int i;
-
- for (i = 0; i < MAXJOBS; i++) {
- if (jobs[i].pid != 0) {
- printf("[%d] (%d) ", jobs[i].jid, jobs[i].pid);
- switch (jobs[i].state) {
- case BG:
- printf("Running ");
- break;
- case FG:
- printf("Foreground ");
- break;
- case ST:
- printf("Stopped ");
- break;
- default:
- printf("listjobs: Internal error: job[%d].state=%d ",
- i, jobs[i].state);
- }
- printf("%s", jobs[i].cmdline);
- }
- }
-}
-/******************************
- * end job list helper routines
- ******************************/
-
-
-/***********************
- * Other helper routines
- ***********************/
-
-/*
- * usage - print a help message
- */
-void usage(void)
-{
- printf("Usage: shell [-hvp]\n");
- printf(" -h print this message\n");
- printf(" -v print additional diagnostic information\n");
- printf(" -p do not emit a command prompt\n");
- exit(1);
-}
-
-/*
- * unix_error - unix-style error routine
- */
-void unix_error(char *msg)
-{
- fprintf(stdout, "%s: %s\n", msg, strerror(errno));
- exit(1);
-}
-
-/*
- * app_error - application-style error routine
- */
-void app_error(char *msg)
-{
- fprintf(stdout, "%s\n", msg);
- exit(1);
-}
-
-/*
- * Signal - wrapper for the sigaction function
- */
-handler_t *Signal(int signum, handler_t *handler)
-{
- struct sigaction action, old_action;
-
- action.sa_handler = handler;
- sigemptyset(&action.sa_mask); /* block sigs of type being handled */
- action.sa_flags = SA_RESTART; /* restart syscalls if possible */
-
- if (sigaction(signum, &action, &old_action) < 0)
- unix_error("Signal error");
- return (old_action.sa_handler);
-}
-
-/*
- * sigquit_handler - The driver program can gracefully terminate the
- * child shell by sending it a SIGQUIT signal.
- */
-void sigquit_handler(int sig)
-{
- printf("Terminating after receipt of SIGQUIT signal\n");
- exit(1);
-}
-
-
-
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