65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
|
/*
|
||
|
|
** This file implements a simple command-line utility that shows all of the
|
||
|
|
** Posix Advisory Locks on a file.
|
||
|
|
**
|
||
|
|
** Usage:
|
||
|
|
**
|
||
|
|
** showlocks FILENAME
|
||
|
|
**
|
||
|
|
** To compile: gcc -o showlocks showlocks.c
|
||
|
|
*/
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <fcntl.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
/* This utility only looks for locks in the first 2 billion bytes */
|
||
|
|
#define MX_LCK 2147483647
|
||
|
|
|
||
|
|
/*
|
||
|
|
** Print all locks on the inode of "fd" that occur in between
|
||
|
|
** lwr and upr, inclusive.
|
||
|
|
*/
|
||
|
|
static int showLocksInRange(int fd, off_t lwr, off_t upr){
|
||
|
|
int cnt = 0;
|
||
|
|
struct flock x;
|
||
|
|
|
||
|
|
x.l_type = F_WRLCK;
|
||
|
|
x.l_whence = SEEK_SET;
|
||
|
|
x.l_start = lwr;
|
||
|
|
x.l_len = upr-lwr;
|
||
|
|
fcntl(fd, F_GETLK, &x);
|
||
|
|
if( x.l_type==F_UNLCK ) return 0;
|
||
|
|
printf("start: %-12d len: %-5d pid: %-5d type: %s\n",
|
||
|
|
(int)x.l_start, (int)x.l_len,
|
||
|
|
x.l_pid, x.l_type==F_WRLCK ? "WRLCK" : "RDLCK");
|
||
|
|
cnt++;
|
||
|
|
if( x.l_start>lwr ){
|
||
|
|
cnt += showLocksInRange(fd, lwr, x.l_start-1);
|
||
|
|
}
|
||
|
|
if( x.l_start+x.l_len<upr ){
|
||
|
|
cnt += showLocksInRange(fd, x.l_start+x.l_len+1, upr);
|
||
|
|
}
|
||
|
|
return cnt;
|
||
|
|
}
|
||
|
|
|
||
|
|
int main(int argc, char **argv){
|
||
|
|
int fd;
|
||
|
|
int cnt;
|
||
|
|
|
||
|
|
if( argc!=2 ){
|
||
|
|
fprintf(stderr, "Usage: %s FILENAME\n", argv[0]);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
fd = open(argv[1], O_RDWR, 0);
|
||
|
|
if( fd<0 ){
|
||
|
|
fprintf(stderr, "%s: cannot open %s\n", argv[0], argv[1]);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
cnt = showLocksInRange(fd, 0, MX_LCK);
|
||
|
|
if( cnt==0 ) printf("no locks\n");
|
||
|
|
close(fd);
|
||
|
|
return 0;
|
||
|
|
}
|