result

src/built_in.c

@@ -5,8 +5,15 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <linux/limits.h>
-
+#include <signal.h>
 #include "built_in.h"
+#include "signal_handlers.h"
+#include "commands.h"
+
+
+int pid_list[512];
+
+void add_pid(int pid){pid_list[sizeof(pid_list)] = pid;}
 
 int do_cd(int argc, char** argv) {
   if (!validate_cd_argv(argc, argv))
@@ -35,16 +42,21 @@ int do_pwd(int argc, char** argv) {
 int do_fg(int argc, char** argv) {
   if (!validate_fg_argv(argc, argv))
     return -1;
+  int pid;
 
   char curdir[PATH_MAX];
-  int pid = getpid();
   getcwd(curdir , PATH_MAX);
   printf("%s running\t %s\n",pid,curdir);
 
+  signal(19,SIG_DFL);
+  while(pid == NULL)
+    pid = pid_list;
 
+  kill(pid,18);
   return 0;
 }
 
+
 int validate_cd_argv(int argc, char** argv) {
   if (argc != 2) return 0;
   if (strcmp(argv[0], "cd") != 0) return 0;

src/commands.c

@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
-
+#include <unistd.h>
 #include "commands.h"
 #include "built_in.h"
 
@@ -12,6 +12,9 @@ static struct built_in_command built_in_commands[] = {
   { "fg", do_fg, validate_fg_argv }
 };
 
+int pid_list[512];
+int n_pid=0;
+
 static int is_built_in_command(const char* command_name)
 {
   static const int n_built_in_commands = sizeof(built_in_commands) / sizeof(built_in_commands[0]);
@@ -29,25 +32,53 @@ static int is_built_in_command(const char* command_name)
  * Description: Currently this function only handles single built_in commands. You should modify this structure to launch process and offer pipeline functionality.
  */
  
-void creation_process(const char *Path, char *const argv[]){
-  pid_t pid;
+int background(int argc, char** argv){
+  int pid, buf;
+  if(!validate_bg(argc,argv))
+    return -1;
 
-  const char use_path = Path + 
+  buf = process_creation(argv);
+  if(buf == -1)
+    return -1;
 
-  pid = fork();
+  if(buf>0)
+    pid = buf;
 
-  if(pid>=0){
-    if(pid == 0)
-	execv(Path, argv);
-    else
-  }
-  else{
-    printf("Sorry, Fork failed.\n");
+  add_pid(pid);
+  printf("%d",pid);
   return 1;   
 }
+
+int validate_bg(int argc, char** argv){
+  if(argc != 1)
+    return 0;
+  if(strcmp(argv[0], "&") != 0)
     return 0;
+  if(access(argv[0],F_OK) == 0)
+    return 0;
+
+  return 1;
 }
 
+int process_creation(struct single_command (*commands)[]){
+  int  pid;
+  struct single_command *com=(*commands);
+  char path[4096];
+  strcpy(path,(*com).argv[0]);
+
+  pid = fork(); 
+
+
+  if(pid>=0){
+    if(pid == 0)
+      execv(path,(*com).argv);
+
+    return pid;
+  }else{
+    printf("Sorry, Fork Failed!");
+    return -1;
+  }
+}
 
 int evaluate_command(int n_commands, struct single_command (*commands)[512])
 {  
@@ -70,6 +101,13 @@ int evaluate_command(int n_commands, struct single_command (*commands)[512])
       return 0;
     } else if (strcmp(com->argv[0], "exit") == 0) {
       return 1;
+    }else if(strcmp(com->argv[n_commands], "&") == 0){
+      if(background(com->argc,com->argv) == -1)
+	return -1;
+
+      return 0;
+    }else if (process_creation((commands))==-1){
+	return 0;
     }else{
       fprintf(stderr, "%s: command not found\n", com->argv[0]);
       return -1;
@@ -92,7 +130,8 @@ void free_commands(int n_commands, struct single_command (*commands)[512])
     }
 
     free(argv);
-  }
+
 
   memset((*commands), 0, sizeof(struct single_command) * n_commands);
   }
+}

src/main.c

@@ -5,14 +5,19 @@
 #include "commands.h"
 #include "built_in.h"
 #include "utils.h"
-
+#include "signal_handlers.h"
+#include <signal.h>
 int main()
 {
   char buf[8096];
 
   while (1) {
+
+    signal(SIGINT,catch_sigint);
+    signal(SIGTSTP,catch_sigtstp);
     fgets(buf, 8096, stdin);
     
+
     struct single_command commands[512];
     int n_commands = 0;
     mysh_parse_command(buf, &n_commands, &commands);

src/signal_handlers.c

 #include "signal_handlers.h"
+#include <signal.h>
 
 void catch_sigint(int signalNo)
 {
-  while(1)
-   sleep(1);
+  signal(signalNo,SIG_IGN);
 }
 
 void catch_sigtstp(int signalNo)
 {
-	
+  signal(18,SIG_DFL);
 }

src/utils.c

@@ -12,7 +12,7 @@ void mysh_parse_command(const char* command,
   strcpy(buf, command);
 
   char *saveptr = NULL;
-  char *tok = strtok_r(buf, "|", &saveptr);
+  char *tok = strtok_r(buf, "|", &saveptr);//pipe
 
   int ti = 0;