ENH: allowed parent, child process concurrency

Author: dalmia

3-Process Concept/project - shell/.fuse_hidden00000d6900000003

@@ -1,12 +1,20 @@
 #include <sys/types.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <string.h>
 #include <stdlib.h>
 
+typedef int bool;
+
+#define true 1
+#define false 0
 #define LSH_RL_BUFSIZE 1024 /* buffer size for reading user input */
 #define LSH_TOK_BUFSIZE 64
 #define LSH_TOK_DELIM " \t\r\n\a"
 
+/* global variable to check parent and child process concurrency */
+bool conc = false;
+
 /* Function declarations for built-in shell commands */
 int lsh_cd(char **args);
 int lsh_help(char **args);
@@ -46,7 +54,7 @@ int lsh_cd(char **args)
 int lsh_help(char **args)
 {
  int i;
- printf("Aman Dalmia's LSH\n", );
+ printf("Aman Dalmia's LSH\n");
  printf("Type program names and arguments, and press enter\n");
  printf("The following are built in:\n");
 
@@ -73,13 +81,16 @@ int lsh_launch(char **args){
  if(execvp(args[0], args) == -1) perror("lsh");
  exit(EXIT_FAILURE);
  }else if(pid > 0){ /* parent process */
- do{
- wpid = waitpid(pid, &status, WUNTRACED);
- }while(!WIFEXITED(status) && !WIFSIGNALED(status));
+ if(!conc){
+ do{
+ wpid = waitpid(pid, &status, WUNTRACED);
+ }while(!WIFEXITED(status) && !WIFSIGNALED(status));
+ }
  }else{ /* error forking */
  perror("lsh");
  }
 
+ conc = false;
  return 1;
 }
 
@@ -102,7 +113,7 @@ int lsh_execute(char **args){
 
 /* Parse input to get the arguments */
 char **lsh_split_line(char *line){
- int bufsize = LSH_TOK_DELIM, position = 0;
+ int bufsize = LSH_TOK_BUFSIZE, position = 0;
  char **tokens = malloc(bufsize * sizeof(char*));
  char *token;
 
@@ -127,6 +138,10 @@ char **lsh_split_line(char *line){
 
  token = strtok(NULL, LSH_TOK_DELIM);
  }
+ if(strcmp(tokens[position - 1], "&") == 0) {
+ conc = true;
+ tokens[position - 1] = NULL;
+ }
  tokens[position] = NULL;
  return tokens;
 }
@@ -146,7 +161,7 @@ char *lsh_read_line(void)
 
  while(1){
  /* Read a character */
- c = getchar()
+ c = getchar();
 
  if(c == EOF || c == '\n'){
  buffer[position] = '\0';
@@ -178,8 +193,8 @@ void lsh_loop(void)
  do {
  printf(">");
  line = lsh_read_line();
- args = lsh_split_line();
- status = lsh_execute(line);
+ args = lsh_split_line(line);
+ status = lsh_execute(args);
 
  free(line);
  free(args);

3-Process Concept/project - shell/.fuse_hidden00000d6a00000004

@@ -0,0 +1,16 @@
+#include <stdio.h>
+
+int main(void)
+{
+ int p1[10];
+ int *p2[10];
+ int (*p3)[10];
+
+ printf("sizeof(int) = %d\n", (int)sizeof(int));
+ printf("sizeof(int *) = %d\n", (int)sizeof(int *));
+ printf("sizeof(p1) = %d\n", (int)sizeof(p1));
+ printf("sizeof(p2) = %d\n", (int)sizeof(p2));
+ printf("sizeof(p3) = %d\n", (int)sizeof(p3));
+
+ return 0;
+}