init commit of lab4_challenge1

Makefile

@@ -68,7 +68,7 @@ USER_CPPS 		:= user/*.c
 USER_CPPS  		:= $(wildcard $(USER_CPPS))
 USER_OBJS  		:= $(addprefix $(OBJ_DIR)/, $(patsubst %.c,%.o,$(USER_CPPS)))
 
-USER_TARGET 	:= $(OBJ_DIR)/app_hardlink
+USER_TARGET 	:= $(OBJ_DIR)/app_relativepath
 #------------------------targets------------------------
 $(OBJ_DIR):
 	@-mkdir -p $(OBJ_DIR)	

user/app_hardlink.c

@@ -1,94 +0,0 @@
-#include "user_lib.h"
-#include "util/string.h"
-#include "util/types.h"
-
-void ls(char *path) {
-  int dir_fd = opendir_u(path);
-  printu("------------------------------\n");
-  printu("ls \"%s\":\n", path);
-  printu("[name]               [inode_num]\n");
-  struct dir dir;
-  int width = 20;
-  while(readdir_u(dir_fd, &dir) == 0) {
-    // we do not have %ms :(
-    char name[width + 1];
-    memset(name, ' ', width + 1);
-    name[width] = '\0';
-    if (strlen(dir.name) < width) {
-      strcpy(name, dir.name);
-      name[strlen(dir.name)] = ' ';
-      printu("%s %d\n", name, dir.inum);
-    }
-    else
-      printu("%s %d\n", dir.name, dir.inum);
-  }
-  printu("------------------------------\n");
-  closedir_u(dir_fd);
-}
-
-int main(int argc, char *argv[]) {
-  int MAXBUF = 512;
-  char str[] = "hello world";
-  char buf[MAXBUF];
-  int fd1, fd2;
-  
-  printu("\n======== establish the file ========\n");
-
-  fd1 = open("/RAMDISK0/ramfile", O_RDWR | O_CREAT);
-  printu("create file: /RAMDISK0/ramfile\n");
-  close(fd1);
-
-  printu("\n======== Test 1: hard link ========\n");
-
-  link_u("/RAMDISK0/ramfile", "/RAMDISK0/ramfile2");
-  printu("create hard link: /RAMDISK0/ramfile2 -> /RAMDISK0/ramfile\n");
-
-  fd1 = open("/RAMDISK0/ramfile", O_RDWR);
-  fd2 = open("/RAMDISK0/ramfile2", O_RDWR);
-  
-  printu("file descriptor fd1 (ramfile): %d\n", fd1);
-  printu("file descriptor fd2 (ramfile2): %d\n", fd2);
-
-  // check the number of hard links to ramfile on disk
-  struct istat st;
-  disk_stat_u(fd1, &st);
-  printu("ramfile hard links: %d\n", st.st_nlinks);
-  if (st.st_nlinks != 2) {
-    printu("ERROR: the number of hard links to ramfile should be 2, but it is %d\n",
-             st.st_nlinks);
-    exit(-1);
-  }
-  
-  write_u(fd1, str, strlen(str));
-  printu("/RAMDISK0/ramfile write content: \n%s\n", str);
-
-  read_u(fd2, buf, MAXBUF);
-  printu("/RAMDISK0/ramfile2 read content: \n%s\n", buf);
-
-  close(fd1);
-  close(fd2);
-
-  printu("\n======== Test 2: unlink ========\n");
-
-  ls("/RAMDISK0");
-
-  unlink_u("/RAMDISK0/ramfile");
-  printu("unlink: /RAMDISK0/ramfile\n");
-
-  ls("/RAMDISK0");
-
-  // check the number of hard links to ramfile2 on disk
-  fd2 = open("/RAMDISK0/ramfile2", O_RDWR);
-  disk_stat_u(fd2, &st);
-  printu("ramfile2 hard links: %d\n", st.st_nlinks);
-  if (st.st_nlinks != 1) {
-    printu("ERROR: the number of hard links to ramfile should be 1, but it is %d\n",
-             st.st_nlinks);
-    exit(-1);
-  }
-  close(fd2);
-
-  printu("\nAll tests passed!\n\n");
-  exit(0);
-  return 0;
-}

user/app_relativepath.c

@@ -0,0 +1,67 @@
+#include "user_lib.h"
+#include "util/string.h"
+#include "util/types.h"
+
+void pwd() {
+  char path[30];
+  read_cwd(path);
+  printu("cwd:%s\n", path);
+}
+
+void cd(const char *path) {
+  if (change_cwd(path) != 0)
+    printu("cd failed\n");
+}
+
+int main(int argc, char *argv[]) {
+  int fd;
+  int MAXBUF = 512;
+  char buf[MAXBUF];
+  char str[] = "hello world";
+  int fd1, fd2;
+
+  printu("\n======== Test 1: change current directory  ========\n");
+
+  pwd();
+  cd("./RAMDISK0");
+  printu("change current directory to ./RAMDISK0\n");
+  pwd();
+
+  printu("\n======== Test 2: write/read file by relative path  ========\n");
+  printu("write: ./ramfile\n");
+
+  fd = open("./ramfile", O_RDWR | O_CREAT);
+  printu("file descriptor fd: %d\n", fd);
+
+  write_u(fd, str, strlen(str));
+  printu("write content: \n%s\n", str);
+  close(fd);
+
+  fd = open("./ramfile", O_RDWR);
+  printu("read: ./ramfile\n");
+
+  read_u(fd, buf, MAXBUF);
+  printu("read content: \n%s\n", buf);
+  close(fd);
+
+  printu("\n======== Test 3: Go to parent directory  ========\n");
+
+  pwd();
+  cd("..");
+  printu("change current directory to ..\n");
+  pwd();
+  
+  printu("read: ./hostfile.txt\n");
+
+  fd = open("./hostfile.txt", O_RDONLY);
+  printu("file descriptor fd: %d\n", fd);
+
+  read_u(fd, buf, MAXBUF);
+  printu("read content: \n%s\n", buf);
+
+  close(fd);
+
+  printu("\nAll tests passed!\n\n");
+  exit(0);
+  return 0;
+}

user/user_lib.c

@@ -167,3 +167,17 @@ int unlink_u(const char *fn){
 int close(int fd) {
   return do_user_call(SYS_user_close, fd, 0, 0, 0, 0, 0, 0);
 }
+
+//
+// lib call to read present working directory (pwd)
+//
+int read_cwd(char *path) {
+  return do_user_call(SYS_user_rcwd, (uint64)path, 0, 0, 0, 0, 0, 0);
+}
+
+//
+// lib call to change pwd
+//
+int change_cwd(const char *path) {
+  return do_user_call(SYS_user_ccwd, (uint64)path, 0, 0, 0, 0, 0, 0);
+}

user/user_lib.h

@@ -33,5 +33,7 @@ int closedir_u(int fd);
 int link_u(const char *fn1, const char *fn2);
 int unlink_u(const char *fn);
 
+int read_cwd(char *path);
+int change_cwd(const char *path);
 
 #endif