Programming

Hi.
A questions on unix sytem's directory inode and file inode. Unix have system function's that can get the following stat information out to user ( readdir, lstat.etc)
struct stat {
dev_t st_dev; /* device */
ino_t st_ino; /* inode */
mode_t st_mode; /* protection */
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 type (if inode device) */ off_t st_size; /* total size, in bytes */
blksize_t st_blksize; /* blocksize for filesystem I/O */
blkcnt_t st_blocks; /* number of blocks allocated */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last modification */
time_t st_ctime; /* time of last change */
};
I am wondering are there functions, I can pass in the st_dev and st_ino information and then get the file name and directory absolute path out, like a reversed function.

Thank you.

No such function, you would need to search for it. And bear in mind that a file can have zero or more paths that point to it. There may be no answer or there may be many.

"And bear in mind that a file can have zero or more paths that point to it."

More path means there are simbolic links, right? what is zero path mean? Thank you.

Not soft links, hard links.

Code:

$ cd dir
$ touch a
$ ln a b
$ ln a c
$ ls -i1
288735 a
288735 b
288735 c
$

a, b, and c are all links to the same file. Same device number and same inode number.

As for zero links, when you remove the last hard link to a file, the file will not be freed if a program has it open. So a program can create a file and then unlink it. The file will disappear when the program exits. Very handy for temp files. It is a problem for newbie admins though. A file system will get full, they locate a large file, rm the large file, and then wonder why the space is still allocated. example