NAME

fuser − Reports PIDs and UIDs for files, file systems and/or the devices attached to them. 

SYNOPSIS

#include <sys/fuser.h>
int fuser(
        char ∗file,
        long flag,
        struct f_user fuser_array[],
        long sizeof_fuser_array );

PARAMETERS

fileSpecifies the file name. 

flagSpecifies one of the following values.  If none of the following are values are specified, the default is to match open files. 

F_FILE_ONLY
Matches only file ids.

F_CONTAINED
Provides mount point matching.

F_NOLINK
Matches deleted files on the mount point specified by file. 

fuser_array
Specifies the array.

sizeof_fuser_array
Specifies the number of elements in the fuser array. 

DESCRIPTION

The fuser function reports a list of PIDs and UIDs that are associated with a specified file, file system, and/or the devices that are attached to them. 

The fuser function can report back additional information about “matches” by ORing one of the following constants that can be passed back in the member fu_flags:

F_CDIR
Current directory

F_RDIR
Current directory

F_PDIR
Parent of the current directory

F_OPEN
At least one file open, but the number open is not known.

F_TEXT
Executable image.

F_TTY
Controlling terminal

F_TRACE
Trace

F_MMAP
At least one file is mmapped

RETURN VALUES

On success, the fuser function returns the number of fuser_array elements that were found. The contents of the structure are as follows:

typedef struct  f_user {
        pid_t   fu_pid;
        int     fu_flags;
        uid_t   fu_uid;
} f_user_t;

If an error has occurred, the fuser function returns -1 and sets errno to indicate the error. 

ERRORS

If the fuser function fails, errno may be set to one of the following values:

[EINVAL]
The array is not large enough to hold the number of array elements returned or the array structure cannot be filled

[ENOENT]
The file parameter specified does not exist

EXAMPLES

     1.Open regular files and special files are matched using the flag parameter set at 0L. Thus, if process 127 and 3220 open the /home/try file simultaneously and the fuser function is active, the PIDs and UIDs associated with the home/try file are reported as in the following example:

fuser("/home/try", 0L, fuser_array, \
     (long) (sizeof (fuser_array)/sizeof(fuser_array[0]));

     2.Similarly, if the special device file /dev/ttyp2 is open by process 32, then that PID and its associated UID are reported as in the following example:

fuser("/dev/ttyp2", 0L, fuser_array, \
     (long) (sizeof (fuser_array)/sizeof(fuser_array[0]));