我正在编写代码以使用 c 程序实现 ls-al 命令，我已经让我的代码在没有打印权限的情况下实现它，但我也想实现权限，但不知道如何实现。 有什么建议吗？ 我的代码如下
#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
#include <pwd.h>
// Last Modified
time_t t = my_stat.st_mtime;
localtime_r(&t, <);
char timebuf[80];
strftime(timebuf, sizeof(timebuf), "%c", <);
if (pwd != 0) {
printf("%s t %ld t %s t %s", pwd->pw_name, (long)my_stat.st_size, timebuf, current_directory->d_name);
printf("n");
} else {
printf("%d t %ld t %s t %s", my_stat.st_uid, (long)my_stat.st_size, timebuf, current_directory->d_name);
printf("n");
}
}
closedir(directory);
return 0;
}
int main(int argc, char* argv[]) {
if ( argc == 1 ) {
return list_dir ( "." );
} else {
int ret = 0;
for (int i = 1; i < argc; i += 1 ) {
if ( list_dir ( argv[i] ) != 0 ) {
ret = 1;
}
}
return ret;
}
}
我已经尝试了很长时间才能为这段代码添加权限，但我似乎陷入困境并且在这里没有想法
我的代码输出是：
kev 0 Thu Jun 20 13:39:49 2019 .
kev 0 Thu Jun 20 13:39:46 2019 ..
kev 24147 Thu Jun 20 12:24:40 2019 CMakeCache.txt
kev 0 Thu Jun 20 13:39:53 2019 CMakeFiles
kev 1426 Thu Jun 20 12:24:41 2019 cmake_install.cmake
kev 5160 Thu Jun 20 12:24:41 2019 Makefile
预期输出为：
rw-r--r-- 1 kev 0 Thu Jun 20 13:39:49 2019 .
rw-r--r-- 1 kev 0 Thu Jun 20 13:39:46 2019 ..
-rw------- 24147 Thu Jun 20 12:24:40 2019 CMakeCache.txt
rw-r--r-- kev 0 Thu Jun 20 13:39:53 2019 CMakeFiles
-rw------- kev 1426 Thu Jun 20 12:24:41 2019 cmake_install.cmake
rw-r--r-- kev 5160 Thu Jun 20 12:24:41 2019 Makefile
您需要
利用struct stat的mode_t st_mode字段。 查看统计(2(：
统计结构
所有这些系统调用都返回一个统计信息结构，其中包含以下字段：
struct stat { dev_t st_dev; /* ID of device containing file */ ino_t st_ino; /* inode number */ mode_t st_mode; /* file type and mode */ nlink_t st_nlink; /* number of hard links */ uid_t st_uid; /* user ID of owner */ gid_t st_gid; /* group ID of owner */ dev_t st_rdev; /* device ID (if special file) */ off_t st_size; /* total size, in bytes */ blksize_t st_blksize; /* blocksize for filesystem I/O */ blkcnt_t st_blocks; /* number of 512B blocks allocated */ /* Since Linux 2.6, the kernel supports nanosecond precision for the following timestamp fields. For the details before Linux 2.6, see NOTES. */ struct timespec st_atim; /* time of last access */ struct timespec st_mtim; /* time of last modification */ struct timespec st_ctim; /* time of last status change */ #define st_atime st_atim.tv_sec /* Backward compatibility */ #define st_mtime st_mtim.tv_sec #define st_ctime st_ctim.tv_sec };
[...]
文件类型和模式 (st_mode(
POSIX 将掩码S_IFMT对应的 st_mode 位(见下文(称为文件类型，将掩码 07777 对应的 12 位称为文件模式位，将最低有效 9 位 (0777( 称为文件权限 位。
为st_mode字段的文件类型定义了以下掩码值：
S_IFMT 0170000 bit mask for the file type bit field S_IFSOCK 0140000 socket S_IFLNK 0120000 symbolic link S_IFREG 0100000 regular file S_IFBLK 0060000 block device S_IFDIR 0040000 directory S_IFCHR 0020000 character device S_IFIFO 0010000 FIFO
[...]
为 st_mode 字段的文件模式组件定义了以下掩码值：
S_ISUID 04000 set-user-ID bit S_ISGID 02000 set-group-ID bit (see below) S_ISVTX 01000 sticky bit (see below) S_IRWXU 00700 owner has read, write, and execute permission S_IRUSR 00400 owner has read permission S_IWUSR 00200 owner has write permission S_IXUSR 00100 owner has execute permission S_IRWXG 00070 group has read, write, and execute permission S_IRGRP 00040 group has read permission S_IWGRP 00020 group has write permission S_IXGRP 00010 group has execute permission S_IRWXO 00007 others (not in group) have read, write, and execute per‐ mission S_IROTH 00004 others have read permission S_IWOTH 00002 others have write permission S_IXOTH 00001 others have execute permission