1.chgrp实现
#include <grp.h>
#include <unistd.h> void chgrp(char * groupname,char * filename)
{
struct group * groupinfo = NULL;
if((groupinfo = getgrnam(groupname)) == NULL)
{
printf("groupname does not exist\n");
return;
} if(access(filename,F_OK) != 0)
{
printf("file %s does not exist\n",filename);
return;
} int gid = groupinfo->gr_gid;
chown(filename,-1,gid);
printf("the group id of the file has been changed successfully\n");
}
2.chown实现
void chowner(char * ownername,char * filename)
{
struct passwd *password_info = NULL;
if((password_info = getpwnam(ownername)) == NULL)
{
printf("username does not exist\n");
return;
}
if(access(filename,F_OK) != 0)
{
printf("file %s does not exist\n",filename);
return;
}
int uid = password_info->pw_uid;
chown(filename,uid,-1);
printf("the user id of the file has been changed successfully\n");
}
3.chmod实现
void _chmod(char * mod,char * filename)
{
if(access(filename,F_OK) != 0)
{
printf("the file %s does not exist",filename);
return;
} int len = strlen(mod);
switch(len)
{
case 1:
{
int a;
a = mod[0] - '0';
mode_t mode = 0;
if(a < 0 || a > 7)
{
printf("octal number out of range\n");
return ;
}
if(a & 0x04)
mode = mode | S_IROTH;
if(a & 0x02)
mode = mode | S_IWOTH;
if(a & 0x01)
mode = mode | S_IXOTH;
chmod(filename,mode);
printf("the mode has been changed successfully\n");
break;
}
case 2:
{
int a,b;
mode_t mode = 0;
a = mod[0] - '0';
b = mod[1] - '0'; if(a < 0 || a > 7 || b < 0 || b > 7)
{
printf("octal number out of range\n");
return ;
} if(b & 0x04)
mode = mode | S_IROTH;
if(b & 0x02)
mode = mode | S_IWOTH;
if(b & 0x01)
mode = mode | S_IXOTH; if(a & 0x04)
mode = mode | S_IRGRP;
if(a & 0x02)
mode = mode | S_IWGRP;
if(a & 0x01)
mode = mode | S_IXGRP;
chmod(filename,mode);
printf("the mode has been changed successfully\n");
break;
}
case 3:
{
int a,b,c;
mode_t mode = 0;
a = mod[0] - '0';
b = mod[1] - '0';
c = mod[2] - '0'; if(a < 0 || a > 7 || b < 0 || b > 7 || c < 0 || c > 7)
{
printf("octal number out of range\n");
return ;
} if(a & 0x04)
mode = mode | S_IRUSR;
if(a & 0x02)
mode = mode | S_IWUSR;
if(a & 0x01)
mode = mode | S_IXUSR; if(b & 0x04)
mode = mode | S_IRGRP;
if(b & 0x02)
mode = mode | S_IWGRP;
if(b & 0x01)
mode = mode | S_IXGRP; if(c & 0x04)
mode = mode | S_IROTH;
if(c & 0x02)
mode = mode | S_IWOTH;
if(c & 0x01)
mode = mode | S_IXOTH;
chmod(filename,mode);
printf("the mode has been changed successfully\n");
break;
}
default:
{
int a,b,c,d;
mode_t mode = 0;
a = mod[len-4] - '0';
b = mod[len-3] - '0';
c = mod[len-2] - '0';
d = mod[len-1] - '0'; if(a != 0 || b < 0 || b > 7 || c < 0 || c > 7 || d < 0 || d >7)
{
printf("octal number out of range\n");
return ;
} if(b & 0x04)
mode = mode | S_IRUSR;
if(b & 0x02)
mode = mode | S_IWUSR;
if(b & 0x01)
mode = mode | S_IXUSR; if(c & 0x04)
mode = mode | S_IRGRP;
if(c & 0x02)
mode = mode | S_IWGRP;
if(c & 0x01)
mode = mode | S_IXGRP; if(d & 0x04)
mode = mode | S_IROTH;
if(d & 0x02)
mode = mode | S_IWOTH;
if(d & 0x01)
mode = mode | S_IXOTH;
chmod(filename,mode);
printf("the mode has been changed successfully\n");
break;
}
}
}