complement lab03

labs/03_shlab/tsh.c

@@ -4,15 +4,15 @@
  * Name: <fill in>
  * Student id: <fill in>
  */
+#include <ctype.h>
+#include <errno.h>
+#include <signal.h>
 #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>
+#include <unistd.h>
 
 /* Misc manifest constants */
 #define MAXLINE 1024   /* max line size */
@@ -52,7 +52,6 @@ struct job_t {              /* The job struct */
 struct job_t jobs[MAXJOBS]; /* The job list */
 /* End global variables */
 
-
 /* Function prototypes */
 
 /*----------------------------------------------------------------------------
@@ -94,8 +93,7 @@ handler_t *Signal(int signum, handler_t *handler);
 /*
  * main - The shell's main routine
  */
-int main(int argc, char **argv)
+int main(int argc, char **argv) {
-{
     char c;
     char cmdline[MAXLINE];
     int emit_prompt = 1; /* emit prompt (default) */
@@ -169,9 +167,30 @@ int main(int argc, char **argv)
  * background children don't receive SIGINT (SIGTSTP) from the kernel
  * when we type ctrl-c (ctrl-z) at the keyboard.
  */
-void eval(char *cmdline)
+void eval(char *cmdline) {
-{
+    pid_t pid;
-	return;
+    char *argv[MAXARGS];
+
+    int bg = parseline(cmdline, argv);
+
+    if (argv[0] && !builtin_cmd(argv)) {
+        if ((pid = fork()) == 0) {// Child process
+            setpgid(0, 0);        // Set new process group
+
+            if (execve(argv[0], argv, environ) < 0) {
+                printf("%s: Command not found\n", argv[0]);
+                exit(0);
+            }
+        }
+
+        if (!bg) {// Foreground job
+            addjob(jobs, pid, FG, cmdline);
+            waitfg(pid);
+        } else {// Background job
+            addjob(jobs, pid, BG, cmdline);
+            fprintf(stderr, "[%d] (%d) %s", pid2jid(pid), pid, cmdline);
+        }
+    }
 }
 
 /*
@@ -181,8 +200,7 @@ void eval(char *cmdline)
  * 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)
+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 */
@@ -199,8 +217,7 @@ int parseline(const char *cmdline, char **argv)
     if (*buf == '\'') {
         buf++;
         delim = strchr(buf, '\'');
-	}
+    } else {
-	else {
         delim = strchr(buf, ' ');
     }
 
@@ -214,8 +231,7 @@ int parseline(const char *cmdline, char **argv)
         if (*buf == '\'') {
             buf++;
             delim = strchr(buf, '\'');
-		}
+        } else {
-		else {
             delim = strchr(buf, ' ');
         }
     }
@@ -235,24 +251,81 @@ int parseline(const char *cmdline, char **argv)
  * builtin_cmd - If the user has typed a built-in command then execute
  *    it immediately.
  */
-int builtin_cmd(char **argv)
+int builtin_cmd(char **argv) {
-{
+    // Built-in-commands: jobs, bg, fg, quit
-	return 0;     /* not a builtin command */
+
+    if (!strcmp(argv[0], "quit")) {
+        exit(0);
+    } else if (!strcmp(argv[0], "jobs")) {
+        listjobs(jobs);
+        return 1;
+    } else if (!strcmp(argv[0], "bg") || !strcmp(argv[0], "fg")) {
+        do_bgfg(argv);
+        return 1;
+    }
+    return 0;
 }
 
 /*
  * do_bgfg - Execute the builtin bg and fg commands
  */
-void do_bgfg(char **argv)
+void do_bgfg(char **argv) {
-{
+    struct job_t *job = NULL;
+    pid_t pid;
+    int jid;
+
+    if (argv[1] == NULL) {
+        printf("%s command requires PID or %%jobid argument\n", argv[0]);
         return;
     }
 
+    if (argv[1][0] == '%') {
+        if (sscanf(&argv[1][1], "%d", &jid) != 1) {
+            printf("%s: argument must be a PID or %%jobid\n", argv[0]);
+            return;
+        }
+        job = getjobjid(jobs, jid);
+        if (job == NULL) {
+            printf("%s: No such job\n", argv[1]);
+            return;
+        }
+    } else if (isdigit((unsigned char) argv[1][0])) {
+        if (sscanf(argv[1], "%d", &pid) != 1) {
+            printf("%s: argument must be a PID or %%jobid\n", argv[0]);
+            return;
+        }
+        job = getjobpid(jobs, pid);
+        if (job == NULL) {
+            printf("(%s): No such process\n", argv[1]);
+            return;
+        }
+    } else {
+        printf("%s: argument must be a PID or %%jobid\n", argv[0]);
+        return;
+    }
+
+    pid = job->pid;
+
+    if (!strcmp(argv[0], "bg")) {
+        job->state = BG;
+        if (kill(-pid, SIGCONT) < 0)
+            unix_error("kill (SIGCONT) error");
+        printf("[%d] (%d) %s", job->jid, job->pid, job->cmdline);
+    } else { /* fg */
+        job->state = FG;
+        if (kill(-pid, SIGCONT) < 0)
+            unix_error("kill (SIGCONT) error");
+        waitfg(pid);
+    }
+}
+
 /*
  * waitfg - Block until process pid is no longer the foreground process
  */
-void waitfg(pid_t pid)
+void waitfg(pid_t pid) {
-{
+    while (pid == fgpid(jobs)) {
+        sleep(1);
+    }
     return;
 }
 
@@ -267,9 +340,27 @@ void waitfg(pid_t pid)
  *     available zombie children, but doesn't wait for any other
  *     currently running children to terminate.
  */
-void sigchld_handler(int sig)
+void sigchld_handler(int sig) {
-{
+    int olderrno = errno;
-	return;
+    pid_t pid;
+    int status;
+
+    while ((pid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
+        if (WIFEXITED(status)) {
+            deletejob(jobs, pid);
+        } else if (WIFSIGNALED(status)) {
+            fprintf(stderr, "Job [%d] (%d) terminated by signal %d\n", pid2jid(pid), pid, WTERMSIG(status));
+            deletejob(jobs, pid);
+        } else if (WIFSTOPPED(status)) {
+            struct job_t *job = getjobpid(jobs, pid);
+            if (job != NULL) {
+				job->state = ST;
+                fprintf(stderr, "Job [%d] (%d) stopped by signal %d\n", job->jid, pid, WSTOPSIG(status));
+            }
+        }
+    }
+
+    errno = olderrno;
 }
 
 /*
@@ -277,9 +368,11 @@ void sigchld_handler(int sig)
  *    user types ctrl-c at the keyboard.  Catch it and send it along
  *    to the foreground job.
  */
-void sigint_handler(int sig)
+void sigint_handler(int sig) {
-{
+    pid_t pid;
-	return;
+    if ((pid = fgpid(jobs)) > 0) {
+        kill(-pid, SIGINT);
+    }
 }
 
 /*
@@ -287,9 +380,11 @@ void sigint_handler(int sig)
  *     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)
+void sigtstp_handler(int sig) {
-{
+    pid_t pid;
-	return;
+    if ((pid = fgpid(jobs)) > 0) {
+        kill(-pid, SIGTSTP);
+    }
 }
 
 /*********************
@@ -301,8 +396,7 @@ void sigtstp_handler(int sig)
  **********************************************/
 
 /* clearjob - Clear the entries in a job struct */
-void clearjob(struct job_t *job)
+void clearjob(struct job_t *job) {
-{
     job->pid = 0;
     job->jid = 0;
     job->state = UNDEF;
@@ -310,8 +404,7 @@ void clearjob(struct job_t *job)
 }
 
 /* initjobs - Initialize the job list */
-void initjobs(struct job_t *jobs)
+void initjobs(struct job_t *jobs) {
-{
     int i;
 
     for (i = 0; i < MAXJOBS; i++)
@@ -319,8 +412,7 @@ void initjobs(struct job_t *jobs)
 }
 
 /* maxjid - Returns largest allocated job ID */
-int maxjid(struct job_t *jobs)
+int maxjid(struct job_t *jobs) {
-{
     int i, max = 0;
 
     for (i = 0; i < MAXJOBS; i++)
@@ -330,8 +422,7 @@ int maxjid(struct job_t *jobs)
 }
 
 /* addjob - Add a job to the job list */
-int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline)
+int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline) {
-{
     int i;
 
     if (pid < 1)
@@ -356,8 +447,7 @@ int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline)
 }
 
 /* deletejob - Delete a job whose PID=pid from the job list */
-int deletejob(struct job_t *jobs, pid_t pid)
+int deletejob(struct job_t *jobs, pid_t pid) {
-{
     int i;
 
     if (pid < 1)
@@ -374,8 +464,7 @@ int deletejob(struct job_t *jobs, pid_t pid)
 }
 
 /* fgpid - Return PID of current foreground job, 0 if no such job */
-pid_t fgpid(struct job_t *jobs) 
+pid_t fgpid(struct job_t *jobs) {
-{
     int i;
 
     for (i = 0; i < MAXJOBS; i++)
@@ -385,8 +474,7 @@ pid_t fgpid(struct job_t *jobs)
 }
 
 /* getjobpid  - Find a job (by PID) on the job list */
-struct job_t *getjobpid(struct job_t *jobs, pid_t pid)
+struct job_t *getjobpid(struct job_t *jobs, pid_t pid) {
-{
     int i;
 
     if (pid < 1)
@@ -398,8 +486,7 @@ struct job_t *getjobpid(struct job_t *jobs, pid_t pid)
 }
 
 /* getjobjid  - Find a job (by JID) on the job list */
-struct job_t *getjobjid(struct job_t *jobs, int jid)
+struct job_t *getjobjid(struct job_t *jobs, int jid) {
-{
     int i;
 
     if (jid < 1)
@@ -411,8 +498,7 @@ struct job_t *getjobjid(struct job_t *jobs, int jid)
 }
 
 /* pid2jid - Map process ID to job ID */
-int pid2jid(pid_t pid)
+int pid2jid(pid_t pid) {
-{
     int i;
 
     if (pid < 1)
@@ -425,8 +511,7 @@ int pid2jid(pid_t pid)
 }
 
 /* listjobs - Print the job list */
-void listjobs(struct job_t *jobs)
+void listjobs(struct job_t *jobs) {
-{
     int i;
 
     for (i = 0; i < MAXJOBS; i++) {
@@ -454,7 +539,6 @@ void listjobs(struct job_t *jobs)
  * end job list helper routines
  ******************************/
 
-
 /***********************
  * Other helper routines
  ***********************/
@@ -462,8 +546,7 @@ void listjobs(struct job_t *jobs)
 /*
  * usage - print a help message
  */
-void usage(void)
+void usage(void) {
-{
     printf("Usage: shell [-hvp]\n");
     printf("   -h   print this message\n");
     printf("   -v   print additional diagnostic information\n");
@@ -474,8 +557,7 @@ void usage(void)
 /*
  * unix_error - unix-style error routine
  */
-void unix_error(char *msg)
+void unix_error(char *msg) {
-{
     fprintf(stdout, "%s: %s\n", msg, strerror(errno));
     exit(1);
 }
@@ -483,8 +565,7 @@ void unix_error(char *msg)
 /*
  * app_error - application-style error routine
  */
-void app_error(char *msg)
+void app_error(char *msg) {
-{
     fprintf(stdout, "%s\n", msg);
     exit(1);
 }
@@ -492,8 +573,7 @@ void app_error(char *msg)
 /*
  * Signal - wrapper for the sigaction function
  */
-handler_t *Signal(int signum, handler_t *handler)
+handler_t *Signal(int signum, handler_t *handler) {
-{
     struct sigaction action, old_action;
 
     action.sa_handler = handler;
@@ -509,8 +589,7 @@ handler_t *Signal(int signum, handler_t *handler)
  * sigquit_handler - The driver program can gracefully terminate the
  *    child shell by sending it a SIGQUIT signal.
  */
-void sigquit_handler(int sig)
+void sigquit_handler(int sig) {
-{
     printf("Terminating after receipt of SIGQUIT signal\n");
     exit(1);
 }