77 lines
1.7 KiB
C
77 lines
1.7 KiB
C
/*++
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/* NAME
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/* deliver_flock 3
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/* SUMMARY
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/* lock open file for mail delivery
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/* SYNOPSIS
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/* #include <deliver_flock.h>
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/*
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/* int deliver_flock(fd, why)
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/* int fd;
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/* VSTRING *why;
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/* DESCRIPTION
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/* deliver_flock() sets one exclusive kernel lock on an open file
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/* for the purpose of mail delivery. It attempts to acquire
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/* the exclusive lock several times before giving up.
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/*
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/* Arguments:
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/* .IP fd
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/* A file descriptor that is associated with an open file.
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/* .IP why
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/* A null pointer, or storage for diagnostics.
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/* DIAGNOSTICS
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/* deliver_flock() returns -1 in case of problems, 0 in case
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/* of success. The reason for failure is returned via the \fIwhy\fR
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/* parameter.
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/* CONFIGURATION PARAMETERS
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/* deliver_lock_attempts, number of locking attempts
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/* deliver_lock_delay, time in seconds between attempts
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/* sun_mailtool_compatibility, disable kernel locking
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/* LICENSE
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/* .ad
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/* .fi
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/* The Secure Mailer license must be distributed with this software.
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/* AUTHOR(S)
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/* Wietse Venema
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/* IBM T.J. Watson Research
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/* P.O. Box 704
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/* Yorktown Heights, NY 10598, USA
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/*--*/
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/* System library. */
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#include "sys_defs.h"
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#include <unistd.h>
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/* Utility library. */
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#include <vstring.h>
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#include <myflock.h>
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/* Global library. */
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#include "mail_params.h"
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#include "deliver_flock.h"
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/* deliver_flock - lock open file for mail delivery*/
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int deliver_flock(int fd, VSTRING *why)
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{
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int i;
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if (var_mailtool_compat)
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return (0);
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for (i = 0; /* void */ ; i++) {
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if (i >= var_flock_tries)
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break;
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if (i > 0)
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sleep(var_flock_delay);
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if (myflock(fd, MYFLOCK_EXCLUSIVE | MYFLOCK_NOWAIT) == 0)
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return (0);
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}
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if (why)
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vstring_sprintf(why, "unable to lock exclusively: %m");
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return (-1);
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}
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