mycp.c

使用 creat

#include<sys/stat.h>
#include<sys/types.h>
#include<unistd.h>
#include<fcntl.h>
#include<dirent.h>
#include<stdio.h>
#include<string.h>

// to judge if a file is a directory or regular files
// return 1, a dir; 0, regular file; -1, error
int isdir(const char * path)
{
	struct stat bf;
	// read status of the file
	if(stat(path, &bf) == -1){
		printf("isdir(%s), stat(%s) error!\n",path, path);
		return -1;
	}
	if((S_IFMT & bf.st_mode) == S_IFDIR) {
		return 1;
	}
	else
		return 0;
}


// copy a file using open,creat,read and write
// from and to are both absolute path
// return 1, success; 0, error
int cpfile(const char * from, const char * to)
{
	int f1, f2, n;
	char buf[BUFSIZ];
	struct stat old_mode;  
	// read status of the old file
	if(stat(from, &old_mode) == -1){
		printf("cpfile(%s, %s), stat(%s) error!\n", from, to, from);
		return 0;
	}
    // open the old file
	if( (f1 = open(from, O_RDONLY)) == -1){
		printf("cpfile(%s, %s), can't open %s.\n", from, to, from);
		return 0;
	}
    // create new file
	if( (f2 = creat(to,	old_mode.st_mode)) == -1){
		printf("cpfile(%s, %s), can't create %s.\n",  from, to, to);
		close(f1);
		return 0;
	}
	// int fchmod(int fd, mode_t mode)
	if(fchmod(f2, old_mode.st_mode) == -1){
		printf("cpfile(%s, %s), fchmod(%s) error!\n", from, to, to);
		return 0;
	}
	// read and write
	while((n = read(f1, buf, BUFSIZ)) > 0){
		if(write(f2, buf, n) != n){
			printf("cpfile(%s, %s), write(%s) error!\n", from, to, to);
			close(f1);
			close(f2);
			return 0;
		}
	}
	close(f1);
	close(f2);
	return 1;
}

// get file name or directory name
// NAME is stored in name
void getfilename(char * bf, char * name)
{
	int i, n, j;
	n = strlen(bf);
	for(i = n - 1; i >=0 ; i--){
		if(bf[i]=='/'){
			break;
		}
	}
	for(i++, j = 0; i < n; i++, j++)
		name[j] = bf[i];
	name[j] = '\0';
}
// copy a directory, including the files and sub-directories, into a directory that exists
void cpdir(const char * from, const char * to)
{
	 char bffrom[BUFSIZ],  bfto[BUFSIZ]; // use to store filepath of the source and destination
	 char name[BUFSIZ];
	 int flag; 
	 flag = isdir(from);

	 strcpy(bffrom, from);
     strcpy(bfto, to);

	 if(flag == 0) // regular file
	 {
		 getfilename(bffrom, name);  // get file name 
		 strcat(bfto, "/");
		 strcat(bfto, name);
         	 cpfile(bffrom, bfto);
		 return;
	 }
     else 
	 if(flag == 1) // directory
     {
		// make the same dir
		getfilename(bffrom, name);  // get dir name 
		strcat(bfto, "/");
		strcat(bfto, name);

		if(strcmp(name, ".")==0 || strcmp(name, "..")==0 ){
			return ; // current and parent!
		}
		struct stat old_mode;    // get the old_mode

		if(stat(from, &old_mode) == -1){
			printf("mkdir(%s), stat(%s) error!\n", bfto, bffrom);
			return;
		}

		mkdir(bfto, old_mode.st_mode); // make dir bfto

		chmod(bfto, old_mode.st_mode); // change mode of bfto


		// copy the files and subdir in the dir
		DIR * pdir;
		struct dirent * pdirent;

		pdir = opendir(bffrom);
		while(1) {
			pdirent = readdir(pdir) ;
			if(pdirent == NULL)
				break;
			else{
				strcpy(bffrom, from);//key
				strcat(bffrom, "/");
				strcat(bffrom, pdirent->d_name); // subfile or subdir path
				cpdir(bffrom, bfto)  ;   // nested
			}
		}
		closedir(pdir);
		return ;
	 }
	 else
		return ;
}

/*
*some bugs: 
*the source filepath does not exist;
*the destination filepath does not exist, or exists with the same source(care about overwrite);
*the commandline with space and without quotation(the same as the two above);
*/
int main(int argc, char * argv[])
{
	// commandline
	if(argc != 3) {
		printf("usage: %s from to\nwe should use quotation marks if from or to has a space.\n", argv[0]);
		return -1;
	}
	// call 
	cpdir(argv[1], argv[2]);
	//printf("1: %s\n2: %s\n", argv[1] ,argv[2]);
	return 0;
}