今天主要學習了linux的文件操作，有點心塞的感覺，本身對文件不熟悉加上vim編輯器，感覺很心煩，前兩段代碼已理解調試，第三段是實現linux命令中ls功能的代碼，現在是凌晨零點零九分，先暫時把代碼存一下，明天繼續看。
1、標準c函數文件操作，一次最多處理1024個文件
/*************************************************************************
> File Name: test.c
> Author: Comst
> Mail:[email protected]
> Created Time: Tue 27 Jan 2015 09:37:48 AM CST
************************************************************************/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAX 10000000
int main(int argc, char* argv[])
{
FILE** fp_arr = (FILE**)calloc(MAX, sizeof(FILE*));
char buf[1024] = "" ;
int index ;
for(index = 0; index < MAX; index ++)
{
memset(buf, 0, 1024);
sprintf(buf, "%d.txt", index);
fp_arr[index] = fopen(buf, "w");
if(fp_arr[index] == NULL)
{
printf("index: %d\n",index);
break ;
}
}
return 0 ;
}
2、使用linux 中open、read、write函數操作文件
/*************************************************************************
* > File Name: read_file.c
* > Author: Comst
* > Mail:[email protected]
* > Created Time: Tue 27 Jan 2015 10:24:26 AM CST
*************************************************************************/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<fcntl.h>
#include<unistd.h>
int main(int argc, char* argv[])
{
int fd_in = open(argv[1],O_RDONLY );
int fd_out = open(argv[2], O_WRONLY | O_TRUNC);
if(fd_in == -1)
{
perror("fail");
exit(1);
}
if(fd_out == -1)
{
perror("out fail");
exit(1);
}
printf("OK!\n");
char buf[128] = "" ;
int iret ;
iret = read(0, buf, 127);
//write(fd_out, buf, strlen(buf));
write(1, buf, strlen(buf));
printf("readn: %d\nbuf:%s\n", iret, buf);
close(fd_in);
close(fd_out);
return 0 ;
}
3、ls功能實現，暫時還不太懂。
/*************************************************************************
> File Name: my_stat.c
> Author: Comst
> Mail:[email protected]
> Created Time: Tue 27 Jan 2015 03:28:08 PM CST
************************************************************************/
#include<stdio.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<grp.h>
#include<pwd.h>
#include<time.h>
void mode_to_str(mode_t md, char* buf) ;
int main(int argc, char* argv[])
{
struct stat my_stat ;
memset(&my_stat, 0, sizeof(my_stat));
char buf[11] ;
if(-1 == stat(argv[1], &my_stat))
{
perror("stat");
exit(1);
}
printf("mode: %04x\nlink: %u\nuid: %u\ngid: %u\nsize:%u\nmtime:%u\n",my_stat.st_mode, my_stat.st_nlink, my_stat.st_uid, my_stat.st_gid, my_stat.st_size, my_stat.st_mtime );
mode_to_str(my_stat.st_mode, buf);
puts(buf);
printf("%s %s\n", getpwuid(my_stat.st_uid) -> pw_name, getgrgid(my_stat.st_gid) ->gr_name);
printf("%s\n", ctime(&my_stat.st_mtime));
return 0 ;
}
void mode_to_str(mode_t md, char* buf)
{
if(S_ISREG(md))
{
buf[0] ='-' ;
}else if(S_ISDIR(md))
{
buf[0] ='d';
}else if(S_ISCHR(md))
{
buf[0] = 'c' ;
}else if(S_ISBLK(md))
{
buf[0]='b';
}else if(S_ISFIFO(md))
{
buf[0] = 'p';
}else if(S_ISLNK(md))
{
buf[0] = 'l' ;
}else
{
buf[0] = 's' ;
}
if(md & S_IRUSR)
{
buf[1] = 'r' ;
}else
{
buf[1] = '-' ;
}
if(md & S_IWUSR)
{
buf[2] = 'w' ;
}else
{
buf[2] = '-' ;
}
if(md & S_IXUSR)
{
buf[3] = 'x' ;
}else
{
buf[3] = '-' ;
}
if(md & S_IRGRP)
{
buf[4] = 'r' ;
}else
{
buf[4] = '-' ;
}
if(md & S_IWGRP)
{
buf[5] = 'w' ;
}else
{
buf[5] = '-' ;
}
if(md & S_IXGRP)
{
buf[6] = 'x' ;
}else
{
buf[6] = '-' ;
}
if(md & S_IROTH)
{
buf[7] = 'r' ;
}else
{
buf[7] = '-' ;
}
if(md & S_IWOTH)
{
buf[8] = 'w' ;
}else
{
buf[8] = '-' ;
}
if(md & S_IXOTH)
{
buf[9] = 'x' ;
}else
{
buf[9] = '-' ;
}
buf[10] = 0;
}
