done

src/built_in.c

@@ -8,6 +8,8 @@
 
 #include "built_in.h"
 
+int PID=1;
+
 int do_cd(int argc, char** argv) {
   if (!validate_cd_argv(argc, argv))
     return -1;
@@ -36,7 +38,12 @@ int do_fg(int argc, char** argv) {
   if (!validate_fg_argv(argc, argv))
     return -1;
     
-  // TODO: Fill this.
+  int stat;
+  if(PID!=1) {
+    printf("%d running %s\n",PID,running_command);
+    waitpid(PID,&stat,0);
+    PID=1;
+  }
   
   return 0;
 }

src/commands.c

@@ -2,6 +2,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 
 #include "commands.h"
 #include "built_in.h"
@@ -28,6 +31,23 @@ 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 run_command(struct single_command *com)
+{
+  execv(com->argv[0], com->argv);
+  char PATH[50];
+  char* tok, ptrtmp=NULL;
+  sprintf(PATH,"%s",getenv("PATH"));
+  tok=strtok_r(PATH,":",&ptrtmp);
+  while(tok){
+    char PATH_tmp[50];
+    char* tok_tmp=NULL;
+    sprintf(PATH_tmp,"%s/%s",tok,com->argv[0]);
+    execv(PATH_tmp,com->argv);
+    tok=strtok_r(NULL,":",&ptrtmp);
+  }
+}
+
 int evaluate_command(int n_commands, struct single_command (*commands)[512])
 {
   if (n_commands > 0) {
@@ -49,8 +69,25 @@ int evaluate_command(int n_commands, struct single_command (*commands)[512])
       return 0;
     } else if (strcmp(com->argv[0], "exit") == 0) {
       return 1;
-    } else {
+    } else if(n_commands==1) {
+      int pid=fork(), stat=0;
+      if(pid>0)
+      {
+        wait(&stat);
+        return stat ? -1 : 0;
+      }
+      else if(!pid)
+      {
+        run_command(com);
         fprintf(stderr, "%s: command not found\n", com->argv[0]);
+        exit(1);
+      }
+      else if(pid<0)
+      {
+        fprintf(stderr, "fork error\n",com->argv[0]);
+        exit(1);
+      }
+    } else {
       return -1;
     }
   }

src/main.c

@@ -10,6 +10,7 @@ int main()
 {
   char buf[8096];
 
+  putenv("PATH=/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin");
   while (1) {
     fgets(buf, 8096, stdin);
 

src/signal_handlers.c

+#include <stdlib.h>
+#include <unistd.h>
+
 #include "signal_handlers.h"
 
 void catch_sigint(int signalNo)

src/utils.c

@@ -4,9 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-void mysh_parse_command(const char* command,
-                        int* n_commands,
-                        struct single_command (*commands)[])
+void mysh_parse_command(const char* command, int* n_commands, struct single_command (*commands)[])
 {
   char buf[4096];
   strcpy(buf, command);
@@ -28,8 +26,7 @@ void mysh_parse_command(const char* command,
   *n_commands = ti;
 }
 
-void parse_single_command(const char* command,
-                          int *argc, char*** argv)
+void parse_single_command(const char* command, int *argc, char*** argv)
 {
   const int kMaxArgc = 512;
   *argv = (char**)malloc(kMaxArgc * sizeof(char*));