--- /dev/null
+/* Flock.c
+ *
+ * Copyright (C) 2001 Simone Piccardi
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+/*****************************************************************************
+ *
+ * Program Flock.c:
+ * Program to test file locking
+ *
+ * Author: Simone Piccardi
+ * Nov. 2002
+ *
+ * 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 <errno.h> /* error definitions and routines */
+#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 */
+/* user defined header */
+#include "macros.h" /* some useful macros */
+
+/* Help printing routine */
+void usage(void);
+
+int main(int argc, char *argv[])
+{
+/*
+ * 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 */
+ /*
+ * Input section: decode command line parameters
+ * Use getopt function
+ */
+ opterr = 0; /* don't want writing to stderr */
+ while ( (i = getopt(argc, argv, "hs:l:wrbf")) != -1) {
+ switch (i) {
+ /*
+ * Handling options
+ */
+ 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 */
+ break;
+ case 'l': /* take length of the lock */
+ len = strtol(optarg, NULL, 10); /* convert input */
+ break;
+ case 'w': /* set type to write lock */
+ type = F_WRLCK;
+ break;
+ case 'r': /* set type to read lock */
+ type = F_RDLCK;
+ break;
+ case 'b': /* set lock to blocking */
+ cmd = F_SETLKW;
+ break;
+ case 'f': /* enable BSD semantic */
+ bsd = 1;
+ break;
+ case '?': /* unrecognized options */
+ printf("Unrecognized options -%c\n",optopt);
+ usage();
+ default: /* should not reached */
+ usage();
+ }
+ }
+ /* ***********************************************************
+ *
+ * Options processing completed
+ *
+ * Main code beginning
+ *
+ * ***********************************************************/
+ 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 */
+ 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 */
+ perror("Wrong filename");
+ exit(1);
+ }
+ /* do lock */
+ if (bsd) { /* if 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 (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 */
+ /* setting flock structure */
+ 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 */
+ }
+ /* check lock results */
+ if (res) { /* on error exit */
+ perror("Failed lock");
+ exit(1);
+ } else { /* else write message */
+ printf("Lock acquired\n");
+ }
+ pause(); /* stop the process, use a signal to exit */
+ return 0;
+}
+/*
+ * routine to print usage info and exit
+ */
+void usage(void) {
+ printf("Program flock: lock a region of a file \n");
+ printf("Usage:\n");
+ printf(" forktest [-h] [-s start] [-l len] [-w|-r] filename \n");
+ printf(" -h print this help\n");
+ printf(" -s start region starting byte\n");
+ printf(" -l len region length (0 means all file)\n");
+ printf(" -w write lock\n");
+ printf(" -r read lock\n");
+ printf(" -b block when locking impossible\n");
+ printf(" -f enable BSD semantic\n");
+ exit(1);
+}
projects / gapil.git / blobdiff