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archive.c
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archive.c
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/*
CPE 357 Asgn4
Author: Dylan Baxter (dybaxter), Van Park (vpark)
File: mytar.c
Description: This file contains main functionality for home
implement of mytar.c
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <dirent.h>
#include <limits.h>
#include "archive.h"
struct Header* init_Header(){
struct Header* head =(struct Header*)calloc(1,sizeof(struct Header));
/* Initializes the header */
char smallOct[8] = {'\0'};
char bigOct[12] = {'\0'};
strcpy(head->mode, smallOct);
strcpy(head->uid, smallOct);
strcpy(head->gid, smallOct);
strcpy(head->size, bigOct);
strcpy(head->mtime, bigOct);
strcpy(head->chksum, smallOct);
head->typeflag = '0';
strcpy(head->name, "0");
fillArray(head->linkname, 0, 100);
strcpy(head->magic, "ustar");
head->version[0] = '0';
head->version[1] = '0';
fillArray(head->uname, 0,32);
fillArray(head->gname, 0,32);
strcpy(head->devmajor, smallOct);
strcpy(head->devminor, smallOct);
fillArray(head->prefix, 0, 100);
fillArray(head->padding, 0, 12);
return head;
}
struct Header* create_header(char *fileName, char options){
/* Takes the given file name and creates a header. It also takes in an
* option variable to check if the Strict mode has been set */
struct Header* head = init_Header();
char smallOct[8] = {0}; /* Max Octal Size for 8 byte vars */
char bigOct[12] = {0}; /* Max Octal Size for 12 byte vars */
int length = strlen(fileName);
int i;
int breakInd;
int checksum = 0;
/*Stat file*/
struct stat file;
lstat(fileName, &file);
/*Write Name and Prefix*/
char name[100] = {'\0'};
char pre[155] = {'\0'};
char fileTemp[256] = {'\0'};
/*Copy Filename into temp list*/
if(length < 256){
strncpy(fileTemp,fileName,length);
}else{
perror("File name is too long");
exit(EXIT_FAILURE);
}
/*Append slash to directories*/
if(S_ISDIR(file.st_mode)){
if(length<255){
fileTemp[length] = '/';
}
else{
perror("File name is too long");
exit(EXIT_FAILURE);
}
length++;
}
/*Read filname into buffers*/
if (length <= 256 || (options & STRICT)){
if(length > 100){
i = length-100;
for (; i < length; i++){
if(fileTemp[i] == '/'){
breakInd = i;
break;
}
}
for(i=0;i<breakInd;i++){
pre[i] = fileTemp[i];
}
i++;
for(;i<length;i++){
name[i-breakInd-1] = fileTemp[i];
}
}
else{
if(length < 100){
name[length] = '\0';
}
strcpy(name, fileTemp);
}
strcpy(head->name, name);
strcpy(head->prefix, pre);
}
else{
perror("File name is too long");
exit(EXIT_FAILURE);
}
/*Write mode*/
memset(smallOct, '0', 8);
strcpy(head->mode, octalConvert((file.st_mode & 0x1FF), smallOct, 8));
/*Convert usable and write uid*/
if(!(options & STRICT)){
if(insert_special_int(head->uid, 8, file.st_uid)){
perror("insert_special_int");
exit(EXIT_FAILURE);
}
}
else{
memset(smallOct, '0', 8);
strcpy(head->uid, octalConvert(file.st_uid, smallOct, 8));
}
/*Write gid*/
memset(smallOct, '0', 8);
strcpy(head->gid, octalConvert(file.st_gid, smallOct, 8));
/*See Size at dependent*/
/*Write mtime*/
memset(bigOct, 0, 12);
strcpy(head->mtime, octalConvert(file.st_mtime, bigOct, 12));
/*See Checksum at End*/
/*See TypeFlag at dependent*/
/*See Linkname at dependent*/
/*See magic num & version in init*/
/*Write Group and Password*/
struct group *grp;
struct passwd *pwd;
grp = getgrgid(file.st_gid);
pwd = getpwuid(file.st_uid);
strcpy(head->uname, pwd->pw_name);
strcpy(head->gname, grp->gr_name);
/*No Dev Major/Minor*/
/*See prefix at beginning*/
/*Type Dependant Fields*/
if(S_ISREG(file.st_mode)){
head->typeflag = '0';
memset(bigOct, '\0', 8);
strcpy(head->size, octalConvert(file.st_size, bigOct, 12));
}
else if(S_ISDIR(file.st_mode)){
head->typeflag = '5';
memset(bigOct, '0', 8);
strcpy(head->size, octalConvert(0, bigOct, 12));
}
else if(S_ISLNK(file.st_mode)){
head->typeflag = '2';
struct stat sb;
if(stat(fileName, &sb) == -1){
perror("STAT");
exit(EXIT_FAILURE);
}
readlink(fileName, head->linkname, 100);
memset(bigOct, '0', 8);
strcpy(head->size, octalConvert(0, bigOct, 12));
}
/*Count Characters in header and write to checksum*/
unsigned char* countPt = (unsigned char*)head;
memset(head->chksum, ' ', 8);
checksum = 0;
memset(smallOct, '0', 8);
for(i=0;i<BLOCK_SIZE;i++){
/*If offset has a value and is not in checksum
&& ((offset < 148) || (offset > 155))*/
checksum = checksum+*countPt;
countPt++;
}
strcpy(head->chksum, octalConvert(checksum, smallOct, 8));
return head;
}
void createArchive(char* dest, char** paths, int pathCount, int options){
/*Define Variables*/
int i;
int fd;
/*Open New TAR File in destination*/
if(DEBUG){
printf("Opening Dest: %s\n", dest);
}
if((fd = open(dest, O_CREAT|O_TRUNC|O_WRONLY, 0666)) == -1){
perror("Open destination");
exit(EXIT_FAILURE);
}
/*For each path specified*/
for(i=0;i<pathCount;i++){
/*Recursively write each into file*/
writeRecur(fd, paths[i], options);
}
writePad(fd);
if(close(fd)){
perror("Close Dest");
exit(EXIT_FAILURE);
}
}
void writeRecur(int fd, char* path, int options){
/*Open current path*/
if(options & VERBOSE){
printf("%s\n", path);
}
struct stat sb;
DIR* d;
struct dirent* e;
char newpath[MAX_PATH_SIZE];
newpath[0] = '\0';
int flen = 0;
int plen = 0;
/*Stat the current target*/
if(DEBUG){
printf("Recursive Statting: %s\n", path);
}
if(lstat(path, &sb) == -1){
/*perror("Recursive Stat");*/
return;
}
/*If path is a file, write contents to TAR*/
if(S_ISREG(sb.st_mode)){
if(DEBUG){
printf("Writing file: %s\n", path);
}
/*Write Header*/
writeheader(fd, path, options);
/*Write Body*/
writebody(fd, path);
}
/*If the items is a symlink*/
if(S_ISLNK(sb.st_mode)){
/*Write Header*/
writeheader(fd, path, options);
}
/*If path is a directory, write contents to file
Then enter Recursively*/
if(S_ISDIR(sb.st_mode)){
/*Write Header*/
writeheader(fd, path, options);
/*Write Body*/
writebody(fd, path);
/*Open directory*/
if(DEBUG){
printf("Opening Dir: %s\n", path);
}
if((d = opendir(path)) == NULL){
perror("Open Dir");
exit(EXIT_FAILURE);
}
/*For every file in the directory*/
while((e = readdir(d))){
/*Check that new length does not exceed max*/
if(*(e->d_name) != '.'){
flen = strlen(e->d_name);
plen = strlen(path);
if((flen+plen) < MAX_PATH_SIZE){
/*Copy the string to the newpath buffer*/
strcpy(newpath, path);
/*Add the name to the path*/
strncat(newpath, "/" , 2);
strncat(newpath, e->d_name, flen+1);
/*Explore the entry*/
writeRecur(fd, newpath, options);
}
else{
printf("Max path size reached\n");
}
}
}
/*For every entry in the directory*/
while((e = readdir(d))){
/*Check that new length does not exceed max*/
if(*(e->d_name) != '.'){
flen = strlen(e->d_name);
plen = strlen(path);
if((flen+plen) < MAX_PATH_SIZE){
/*Copy the string to the newpath buffer*/
strcpy(newpath, path);
/*Add the name to the path*/
strncat(newpath, "/" , 2);
strncat(newpath, e->d_name, flen+1);
/*Explore the entry*/
writeRecur(fd, newpath, options);
}
else{
printf("Max path size reached\n");
}
}
}
/*Close directory*/
if((closedir(d)) == -1){
perror("Close Dir");
exit(EXIT_FAILURE);
}
}
}
void writebody(int fdout, char* path){
/*Define variables*/
char readBuf[BLOCK_SIZE];
int fdin;
int readSize;
int i;
/*Open read file*/
if(-1==(fdin = open(path, O_APPEND, 0666))){
perror("Body Open");
exit(EXIT_FAILURE);
}
/*While 512 bye blocks exist in read file*/
while(((readSize = read(fdin, readBuf, 512))>0)){
/*If if on last block, pad with 0's*/
if(readSize < BLOCK_SIZE){
for(i=readSize;i<(BLOCK_SIZE);i++){
readBuf[i] = '\0';
}
}
/*Write block*/
if(DEBUG){
printf("Writing Block of Size %d to %d\n", readSize,fdout);
}
if(write(fdout, readBuf, BLOCK_SIZE)==-1){
perror("Body Write");
exit(EXIT_FAILURE);
}
}
/*Close read file*/
if((close(fdin) == -1)){
perror("Body Close");
exit(EXIT_FAILURE);
}
}
void writeheader(int fdout, char* filename, int option){
/*Define variables*/
struct Header* head;
/*Create header object*/
head = create_header(filename, option);
/*Write header variables in order to file*/
write(fdout, head, 512);
free(head);
}
void writePad(int fd){
/*Define variables*/
char readBuf[BLOCK_SIZE] = {'\0'};
/*Write block*/
if(DEBUG){
printf("Writing Padding Block to %d\n", fd);
}
if(write(fd, readBuf, BLOCK_SIZE)==-1){
perror("Pad Write");
exit(EXIT_FAILURE);
}
if(write(fd, readBuf, BLOCK_SIZE)==-1){
perror("Pad Write");
exit(EXIT_FAILURE);
}
}