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文件系统：目录与文件

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lzy
2024-04-30 20:41:19 +08:00
parent ba9f2e37a7
commit 5399da7488
11 changed files with 776 additions and 0 deletions
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34
C13-Linux系统编程/fs/big.c Normal file
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#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
int main(int argc, char **argv)
{
if (argc < 2)
{
fprintf(stderr, "Usage:...\n");
exit(1);
}
int fd;
fd = open(argv[1], O_WRONLY | O_CREAT | O_TRUNC, 0600);
if (fd < 0)
{
perror("open()");
exit(1);
}
// 生成一个5G的文件
// !!! 整数溢出
lseek(fd, 5LL * 1024LL * 1024LL * 1024LL - 1LL, SEEK_SET);
// 写入尾0
write(fd, "", 1);
close(fd);
exit(0);
}

41
C13-Linux系统编程/fs/flen.c Normal file
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#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
// !!! 不是int
static off_t flen(char *fname)
{
struct stat statres;
if (stat(fname, &statres) < 0)
{
perror("stat()");
exit(1);
}
return statres.st_size;
}
/**
* @brief 获取文件大小
* @details
* Usage: ./flen filename
*
* @param argc
* @param argv
* @return int
*/
int main(int argc, char **argv)
{
if (argc < 2)
{
fprintf(stderr, "Usage:...\n");
exit(1);
}
// !!! 通过makefile指定off_t 64位
printf("%lld\n", flen(argv[1]));
exit(0);
}

54
C13-Linux系统编程/fs/ftype.c Normal file
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#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
static int ftype(const char *fname)
{
struct stat statres;
if (stat(fname, &statres) < 0)
{
perror("stat()");
exit(1);
}
if (S_ISREG(statres.st_mode))
return '-';
else if (S_ISDIR(statres.st_mode))
return 'd';
else if (S_ISSOCK(statres.st_mode))
return 's';
else if (S_ISFIFO(statres.st_mode))
return 'p';
else if (S_ISBLK(statres.st_mode))
return 'b';
else if (S_ISCHR(statres.st_mode))
return 'c';
else if (S_ISLNK(statres.st_mode))
return 'l';
else
return '?';
}
/**
* @brief 获取文件类型
* @details
* Usage: ftype <filename>
*
* @param argc
* @param argv
*
* @return int
*/
int main(int argc, char **argv)
{
if (argc < 2)
{
fprintf(stderr, "Usage:...\n");
exit(1);
}
printf("%c\n", ftype(argv[1]));
exit(0);
}

46
C13-Linux系统编程/fs/glob.c Normal file
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#include <glob.h>
#include <stdio.h>
#include <stdlib.h>
// #define PAT "/etc/a*.conf"
#define PAT "/etc/*" // 不包括隐藏文件 .*
#if 0
static int errfunc_(const char *errpath, int eerrno)
{
puts(errpath);
fprintf(stderr, "ERROR MSG: %s\n", strerror(eerrno));
return 0;
}
#endif
/**
* @brief ls /etc/a*.conf
* @details
*
* @param argc
* @param argv
*
* @return int
*/
int main(int argc, char **argv)
{
glob_t globres;
int err;
err = glob(PAT, 0, NULL, &globres);
if (err)
{
printf("ERROR CODE = %d\n", err);
exit(1);
}
for (int i = 0; i < globres.gl_pathc; i++)
{
puts(globres.gl_pathv[i]);
}
// !!!
globfree(&globres);
exit(0);
}

15
C13-Linux系统编程/fs/main.c Normal file
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#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
printf("argc = %d\n", argc);
// for (int i = 0; i < argc; i++)
for (int i = 0; argv[i] != NULL; i++)
{
puts(argv[i]);
}
exit(0);
}

125
C13-Linux系统编程/fs/mydu.c Normal file
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#include <glob.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#define PATHSIZE 1024
static int path_noloop(const char *path)
{
char *pos;
/**
* @brief strrchr
* @details
*
* 找到 path 中最后一个 '/' 字符的位置
*/
pos = strrchr(path, '/');
if (NULL == pos)
exit(1);
if ((0 == strcmp(pos + 1, ".") || 0 == strcmp(pos + 1, "..")))
return 0;
return 1;
}
static int64_t mydu(const char *path)
{
// 优化递归
// 将部分与递归无关的变量拿出栈，用 static 修饰
static struct stat statres;
static char nextpath[PATHSIZE];
glob_t globres;
int64_t sum;
int i;
if (lstat(path, &statres) < 0)
{
perror("lstat()");
exit(1);
}
if (!S_ISDIR(statres.st_mode))
{
/* 非目录 */
return statres.st_blocks;
/*
* st_blocks 代表磁盘块数量，一个磁盘块大小为512字节
* 所以除以2才表示多少个1k字节
*/
}
/* 目录 */
/* 例如：/aaa/bbb/ccc/ddd/eee/fff */
strncpy(nextpath, path, PATHSIZE);
strncat(nextpath, "/*", PATHSIZE); //[W]
// if (glob(nextpath, 0, NULL, &globres))
// {
// perror("glob(), 1");
// exit(1);
// }
glob(nextpath, 0, NULL, &globres);
// !!! 要考虑 . 和 .. 目录
strncpy(nextpath, path, PATHSIZE);
strncat(nextpath, "/.*", PATHSIZE); //[W]
/*
* 这个警告是因为 strncat 函数的第三个参数（即 PATHSIZE）等于目标字符串
* nextpath 的大小。这可能会导致 nextpath 缓冲区溢出，因为 strncat
* 函数会在目标字符串的末尾添加一个 null 字符（'\0'）。
*/
// !!! APPEND
// if (glob(nextpath, GLOB_APPEND, NULL, &globres))
// {
// perror("glob(), APPEND");
// exit(1);
// }
glob(nextpath, 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]);
}
}
// !!!
globfree(&globres);
return sum;
}
/**
* @brief mydu
* @details
* Usage: mydu [FILE]...
*
* 用到了递归的思想
*
* !!! 未考虑权限问题
*
* @param argc
* @param argv
*
* @return int
*/
int main(int argc, char **argv)
{
if (argc < 2)
{
fprintf(stderr, "Usage: mydu [FILE]...\n");
exit(1);
}
printf("%lld\n", mydu(argv[1]) / 2);
exit(0);
}

38
C13-Linux系统编程/fs/readdir.c Normal file
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#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#define PAT "/etc"
/**
* @brief 解析PAT下文件个数
* @details
*
* @param argc
* @param argv
*
* @return int
*/
int main(int argc, char **argv)
{
DIR *dp;
struct dirent *cur;
dp = opendir(PAT);
if (NULL == dp)
{
perror("opendir()");
exit(1);
}
// !!! 注意括号
while ((cur = readdir(dp)) != NULL)
{
puts(cur->d_name);
}
closedir(dp);
exit(0);
}