myfind.c

（1）myfind <pathname> 的功能： 除了具有与程序4-7相同的功能外

#include "apue.h"
#include <dirent.h>
#include <limits.h>
#include <fcntl.h>
#include "pathalloc.c"   //pathalloc.c必须与myfind.c同一个目录
#define	 BUFSIZE	1024 //缓冲区的大小

typedef int Myfunc(const char *,const struct stat *,int);
static Myfunc myfunc,myfunc2,myfunc3;
static int myftw(char *,Myfunc *);
static int dopath(Myfunc *);
static long nreg,ndir,nchr,nblk,nfifo,nslink,nsock,ntot,ngre;//ngre用来统计文件大小<=4096的文件
static long filedes,length;
static char *str;
int main(int argc,char *argv[])
{
    int ret;
    if(argc<2 || argc==3)
        err_quit("usage: myfind <pathname> or myfind <pathname> -comp <filename> or myfind <pathname> -name <str>...\n");
    if(argc==2){
   	 ret=myftw(argv[1],myfunc);
   	 ntot=nreg+ndir+nblk+nchr+nfifo+nslink+nsock;
   	 if(ntot==0)
       		 ntot=1;
   	 printf("regular files				 =%7ld, %5.2f %%\n",nreg,nreg*100.0/ntot);
   	 printf("size of reg_file<=4096B 	         =%7ld, %5.2f %%\n",ngre,ngre*100.0/ntot);
  	 printf("dirctories   				 =%7ld, %5.2f %%\n",ndir,ndir*100.0/ntot);
  	 printf("block special				 =%7ld, %5.2f %%\n",nblk,nblk*100.0/ntot);
  	 printf("char special 				 =%7ld, %5.2f %%\n",nchr,nchr*100.0/ntot);
   	 printf("FIFOS       		 		 =%7ld, %5.2f %%\n",nfifo,nfifo*100.0/ntot);
   	 printf("symbolic links				 =%7ld, %5.2f %%\n",nslink,nslink*100.0/ntot);
   	 printf("sockets      				 =%7ld, %5.2f %%\n",nsock,nsock*100.0/ntot);
    }
    else if(argc==4 && !strcmp(argv[2],"-comp")){//实现第二个功能:查找与argv[3]内容一样的文件
	 if((filedes=open(argv[3],O_RDONLY))==-1)
		err_quit("cannot open\n");
	 if((length=lseek(filedes,0,SEEK_END))==-1)//用length来保存命令中argv[3]文件的大小
		err_quit("lseek error\n");
	 ret=myftw(argv[1],myfunc2);
	 close(filedes);
    }
    else if(argc>=4 && !strcmp(argv[2],"-name")){//实现第三个功能:查找与<str>...相同的文件
	int i,j;
	for(i=4;i<=argc;i++){//用循环处理<str>...中的每一个
		ret=strlen(argv[i-1]);
		if((str=(char *)malloc(ret*sizeof(char)))==NULL)
			err_quit("malloc error\n");
		for(j=ret;argv[i-1][j]!='/' && j>=0;j--) ;//有路径,则定位到去除路径后的位置
		strcpy(str,&argv[i-1][++j]);//用全局变量str来保存文件名
		ret=myftw(argv[1],myfunc3);
		free(str);
	}
    }
    else
	err_quit("usage:myfind <pathname> -comp <filename> or myfind <pathname> -name <str>...\n");
    exit(ret);
}

#define FTW_F 1
#define FTW_D 2
#define FTW_DNR 3
#define FTW_NS 4

static char *fullpath;

static int myftw(char *pathname,Myfunc *func)
{
    int len;
    fullpath=(char *)path_alloc(&len);
    strncpy(fullpath,pathname,len);
    fullpath[len-1]=0;
    return(dopath(func));
}

static int dopath(Myfunc *func)
{
    struct stat statbuf;
    struct dirent *dirp;
    DIR *dp;
    int ret;
    char *ptr;
    if(lstat(fullpath,&statbuf)<0)
       return (func(fullpath,&statbuf,FTW_NS));
    if(S_ISDIR(statbuf.st_mode)==0)
       return (func(fullpath,&statbuf,FTW_F));
    if((ret=func(fullpath,&statbuf,FTW_D))!=0)
       return ret;
    ptr=fullpath+strlen(fullpath);
    *ptr++='/';
    *ptr=0;
    if((dp=opendir(fullpath))==NULL)
       return (func(fullpath,&statbuf,FTW_DNR));
    while((dirp=readdir(dp))!=NULL)
    {
       if(strcmp(dirp->d_name,".")==0 || strcmp(dirp->d_name,"..")==0)
         continue;
       strcpy(ptr,dirp->d_name);
       if((ret=dopath(func))!=0)
         break;
    }
    ptr[-1]=0;
    if(closedir(dp)<0)
       err_ret("can't close directory %s",fullpath);
    return (ret);
}

static int myfunc(const char *pathname,const struct stat *statptr,int type)
{
   	 switch(type){
 	      case FTW_F:
        	    switch(statptr->st_mode&S_IFMT){
                	 case S_IFREG: nreg++;
				       if(statptr->st_size<=4096)
				 		ngre++;
			       	       break;
                	  case S_IFBLK: nblk++; break;
                	  case S_IFCHR: nchr++; break;
            		  case S_IFIFO: nfifo++;break;
            	     	  case S_IFLNK: nslink++; break;
               	 	  case S_IFSOCK: nsock++; break;
                 	  case S_IFDIR: 	; 
          		  }
          	     break;
      	      case FTW_D: ndir++;	break;
      	      case FTW_DNR:	;	break;
              case FTW_NS:	;	break;
              default:		;
  	 }
	return 0;
}

static int myfunc2(const char *pathname,const struct stat *statptr,int type){
	int  filede2,len,i,flags=0;
	long length2;
	char *buf2,*buf,*path;
	if(type==FTW_F){//pathname是文件
		if((filede2=open(pathname,O_RDONLY))==-1)	return 0;
		if(length==statptr->st_size){//大小相同才有可能内容相同
			if(lseek(filedes,0,SEEK_SET)==-1){close(filede2);return 0;}
			i=length/BUFSIZE;//循环的次数
			buf2=(char *)malloc((BUFSIZE+1)*sizeof(char));//最后一个来放'\0'
			buf=(char *)malloc((BUFSIZE+1)*sizeof(char));
			for(len=0;len<i;len++){	//以BUFSIZE大小逐一对两文件进行比较				
				if(read(filedes,buf,BUFSIZE)!=BUFSIZE){	flags=1;break;}
				if(read(filede2,buf2,BUFSIZE)!=BUFSIZE){flags=1;break;}
				buf[BUFSIZE]='\0';buf2[BUFSIZE]='\0';
				if(strcmp(buf,buf2)){flags=1;break;}
			}
			if(flags){free(buf);free(buf2);close(filede2);return 0;}
			else if((i=length%BUFSIZE)!=0){//比较最后大小小于BUFSIZE部分
				if(read(filedes,buf,i)!=i){free(buf);free(buf2);close(filede2);return 0;}
				if(read(filede2,buf2,i)!=i){free(buf);free(buf2);close(filede2); return 0;}
				buf[i]='\0';buf2[i]='\0';
				if(strcmp(buf,buf2)){free(buf);free(buf2);close(filede2);return 0;}
			}
			free(buf2);free(buf);
			if((path=(char *)malloc(strlen(pathname)*sizeof(char)))==NULL){close(filede2); return 0;}
			for(len=strlen(pathname)-1;pathname[len]!='/'&&len>=0;len--) ;//查找pathname文件所在目录
			for(i=0;i<=len;i++)//把文件pathname的目录名拷贝到path里
				path[i]=pathname[i];
			path[i]='\0';
			buf2=path_alloc(&len);
			if(getcwd(buf2,len)==NULL){close(filede2);return 0;}//用buf2保存当前程序所在的目录
			if(chdir(path)==-1){close(filede2);return 0;}//切换到文件pathname所在的目录
			buf=path_alloc(&len);
			if(getcwd(buf,len)==NULL){close(filede2);return 0;}//用buf保存pathname所在的目录
			if(chdir(buf2)==-1){close(filede2);return 0;}//切换回到程序运行所在的目录
			for(i=strlen(pathname)-1;pathname[i]!='/';i--) ;//把pathname文件名提取出来
			strcat(buf,&pathname[i]);
			printf("%s\n",buf);
			free(buf);free(buf2);free(path);
		}
		close(filede2);
	}
        return 0;
}
static int myfunc3(const char *pathname,const struct stat *statptr,int type){
	int len,i;
	char *buf,*path,*buf2;
	if(type==FTW_F){
		if((path=(char *)malloc(strlen(pathname)*sizeof(char)))==NULL)	return 0;
		for(len=strlen(pathname)-1;pathname[len]!='/' && len>=0;len--) ;//查找pathname文件所在目录
		if(!strcmp(str,&pathname[len+1])){//文件名相等
			for(i=0;i<=len;i++)//把文件pathname的目录名拷贝到path里
				path[i]=pathname[i];
			path[i]='\0';
			buf2=path_alloc(&len);
			if(getcwd(buf2,len)==NULL)	return 0;//用buf2保存当前程序所在的目录
			if(chdir(path)==-1)		return 0;//切换到文件pathname所在的目录
			buf=path_alloc(&len);
			if(getcwd(buf,len)==NULL)	return 0;//用buf保存pathname所在的目录
			if(chdir(buf2)==-1)		return 0;//切换回到程序运行所在的目录
			for(i=strlen(pathname)-1;pathname[i]!='/';i--) ;//把pathname文件名提取出来
			strcat(buf,&pathname[i]);
			printf("%s\n",buf);
			free(buf2);free(buf);free(path);
		}
	}
	return 0;
}