*
* Usage: flock -h give all info's
*
- * $Id: Flock.c,v 1.5 2003/05/02 09:55:13 piccardi Exp $
- *
*****************************************************************************/
/*
* Include needed headers
#include <stdlib.h> /* C standard library */
#include <unistd.h> /* unix standard library */
#include <stdio.h> /* standard I/O library */
-#include <string.h> /* string functions */
-#include <fcntl.h> /* string functions */
+#include <string.h> /* C strings library */
+#include <fcntl.h> /* file control functions */
+#include <sys/file.h>
+
/* user defined header */
#include "macros.h" /* some useful macros */
/*
* Variables definition
*/
- int type = F_UNLCK; /* lock type: default to unlock (invalid) */
- off_t start = 0; /* start of the locked region: default to 0 */
- off_t len = 0; /* length of the locked region: default to 0 */
- int fd, res, i; /* internal variables */
- int bsd = 0; /* semantic type: default to POSIX */
- int cmd = F_SETLK; /* lock command: default to non-blocking */
- struct flock lock; /* file lock structure */
+ int type = F_UNLCK; /* lock type: default to unlock (invalid) */
+ off_t start = 0; /* start of the locked region: default to 0 */
+ off_t len = 0; /* length of the locked region: default to 0 */
+ int fd, res, i; /* internal variables */
+ int bsd = 0; /* semantic type: default to POSIX */
+ int cmd = F_SETLK; /* lock command: default to non-blocking */
+ struct flock lock; /* file lock structure */
/*
* Input section: decode command line parameters
* Use getopt function
/*
* Handling options
*/
- case 'h': /* help option */
+ case 'h': /* help option */
printf("Wrong -h option use\n");
usage();
return -1;
break;
- case 's': /* take start point of the lock */
- start = strtol(optarg, NULL, 10); /* convert input */
+ case 's': /* take start point of the lock */
+ start = strtol(optarg, NULL, 10); /* convert input */
break;
- case 'l': /* take length of the lock */
- len = strtol(optarg, NULL, 10); /* convert input */
+ case 'l': /* take length of the lock */
+ len = strtol(optarg, NULL, 10); /* convert input */
break;
- case 'w': /* set type to write lock */
+ case 'w': /* set type to write lock */
type = F_WRLCK;
break;
- case 'r': /* set type to read lock */
+ case 'r': /* set type to read lock */
type = F_RDLCK;
break;
- case 'b': /* set lock to blocking */
+ case 'b': /* set lock to blocking */
cmd = F_SETLKW;
break;
- case 'f': /* enable BSD semantic */
+ case 'f': /* enable BSD semantic */
bsd = 1;
break;
- case '?': /* unrecognized options */
+ case '?': /* unrecognized options */
printf("Unrecognized options -%c\n",optopt);
usage();
- default: /* should not reached */
+ default: /* should not reached */
usage();
}
}
* Main code beginning
*
* ***********************************************************/
- if ((argc - optind) != 1) { /* There must be remaing parameters */
+ if ((argc - optind) != 1) { /* There must be remaing parameters */
printf("Wrong number of arguments %d\n", argc - optind);
usage();
}
- if (type == F_UNLCK) { /* There must be a -w or -r option set */
+ if (type == F_UNLCK) { /* There must be a -w or -r option set */
printf("You should set a read or a write lock\n");
usage();
}
- fd = open(argv[optind], O_RDONLY); /* open the file to be locked */
- if (fd < 0) { /* on error exit */
+ fd = open(argv[optind], O_RDONLY); /* open the file to be locked */
+ if (fd < 0) { /* on error exit */
perror("Wrong filename");
exit(1);
}
/* do lock */
- if (bsd) { /* if BSD locking */
+ if (bsd) { /* BSD locking */
/* rewrite cmd for suitables flock operation values */
- if (cmd == F_SETLK) { /* if no-blocking */
- cmd = LOCK_NB; /* set the value for flock operation */
- } else { /* else */
- cmd = 0; /* default is null */
+ if (cmd == F_SETLK) { /* if no-blocking set for flock operation */
+ cmd = LOCK_NB;
+ } else { /* else default is null */
+ cmd = 0;
}
- if (type == F_RDLCK) cmd |= LOCK_SH; /* set for shared lock */
- if (type == F_WRLCK) cmd |= LOCK_EX; /* set for exclusive lock */
- res = flock(fd, cmd); /* esecute lock */
- } else { /* if POSIX locking */
+ if (type == F_RDLCK) cmd |= LOCK_SH; /* set for shared lock */
+ if (type == F_WRLCK) cmd |= LOCK_EX; /* set for exclusive lock */
+ res = flock(fd, cmd); /* esecute lock */
+ } else { /* POSIX locking */
/* setting flock structure */
- lock.l_type = type; /* set type: read or write */
+ lock.l_type = type; /* set type: read or write */
lock.l_whence = SEEK_SET; /* start from the beginning of the file */
- lock.l_start = start; /* set the start of the locked region */
- lock.l_len = len; /* set the length of the locked region */
- res = fcntl(fd, cmd, &lock); /* do lock */
+ lock.l_start = start; /* set the start of the locked region */
+ lock.l_len = len; /* set the length of the locked region */
+ res = fcntl(fd, cmd, &lock); /* do lock */
}
/* check lock results */
- if (res) { /* on error exit */
+ if (res) { /* on error exit */
perror("Failed lock");
exit(1);
- } else { /* else write message */
+ } else { /* else write message */
printf("Lock acquired\n");
}
- pause(); /* stop the process, use a signal to exit */
+ pause(); /* stop the process, use a signal to exit */
return 0;
}
/*
projects / gapil.git / blobdiff