关于c:程序人生-UNIX环境高级编程技巧之-du-指令实现

本文首发于 2014-07-10 10:00:41

代码

#include <stdio.h>#include <stdlib.h>#include <glob.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#define PATHSIZE 1024static int path_noloop(const char *path){    char *pos;    pos = strrchr(path,'/');//定位最左边的'/'的地位    if(strcmp(pos+1,".") == 0 || (strcmp(pos+1,"..") == 0))        return 0;    return 1;}static int64_t mydu(const char *path){    int i;    glob_t globres;    int64_t sum;    static struct stat statres;    static char nextpath[PATHSIZE];    if(lstat(path, &statres) < 0)    {        perror("lstat()");        return 0;//exit(1);    }    if(!S_ISDIR(statres.st_mode))        return statres.st_blocks;    strncpy(nextpath, path,PATHSIZE);    strncat(nextpath, "/*" , PATHSIZE);    glob(nextpath,GLOB_NOSORT, NULL, &globres);    strncpy(nextpath, path,PATHSIZE);    strncat(nextpath, "/.*" , PATHSIZE);    glob(nextpath,GLOB_NOSORT|GLOB_APPEND, NULL, &globres);    sum = statres.st_blocks;    for(i = 0 ;i < globres.gl_pathc ; i++)    {        if(path_noloop(globres.gl_pathv[i]))            sum += mydu(globres.gl_pathv[i]);    }    return sum;}int main(int argc,char **argv){    if(argc < 2)    {        fprintf(stderr,"Usage...\n");        exit(1);    }    printf("%lld 512B blocks\n", (long long int)mydu(argv[1]));    return 0;}

编译

$ gcc -g -Wall testdu.c -o testdu

运行

• testdf执行成果：

$ ./testdu /usr/bin1766184 512B blocks

• 原生df执行成果：

$ du -sh /usr/bin859M    /usr/bin

欢送关注我的微信公众号【数据库内核】：分享支流开源数据库和存储引擎相干技术。