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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
commit | 5e61585d76ae77fd5e9e96ebabb57afa4d74880d (patch) | |
tree | 2b467823aaeebc7ef8bc9e3cabe8074eaef1666d /src/global/deliver_flock.c | |
parent | Initial commit. (diff) | |
download | postfix-5b7b6342ca8708be5ee306c089f8c5b3d3d122d8.tar.xz postfix-5b7b6342ca8708be5ee306c089f8c5b3d3d122d8.zip |
Adding upstream version 3.5.24.upstream/3.5.24upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/global/deliver_flock.c')
-rw-r--r-- | src/global/deliver_flock.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/src/global/deliver_flock.c b/src/global/deliver_flock.c new file mode 100644 index 0000000..35a6bcb --- /dev/null +++ b/src/global/deliver_flock.c @@ -0,0 +1,82 @@ +/*++ +/* NAME +/* deliver_flock 3 +/* SUMMARY +/* lock open file for mail delivery +/* SYNOPSIS +/* #include <deliver_flock.h> +/* +/* int deliver_flock(fd, lock_style, why) +/* int fd; +/* int lock_style; +/* VSTRING *why; +/* DESCRIPTION +/* deliver_flock() sets one exclusive kernel lock on an open file, +/* for example in order to deliver mail. +/* It performs several non-blocking attempts to acquire an exclusive +/* lock before giving up. +/* +/* Arguments: +/* .IP fd +/* A file descriptor that is associated with an open file. +/* .IP lock_style +/* A locking style defined in myflock(3). +/* .IP why +/* A null pointer, or storage for diagnostics. +/* DIAGNOSTICS +/* deliver_flock() returns -1 in case of problems, 0 in case +/* of success. The reason for failure is returned via the \fIwhy\fR +/* parameter. +/* CONFIGURATION PARAMETERS +/* deliver_lock_attempts, number of locking attempts +/* deliver_lock_delay, time in seconds between attempts +/* sun_mailtool_compatibility, disable kernel locking +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include "sys_defs.h" +#include <unistd.h> + +/* Utility library. */ + +#include <vstring.h> +#include <myflock.h> +#include <iostuff.h> + +/* Global library. */ + +#include "mail_params.h" +#include "deliver_flock.h" + +/* Application-specific. */ + +#define MILLION 1000000 + +/* deliver_flock - lock open file for mail delivery */ + +int deliver_flock(int fd, int lock_style, VSTRING *why) +{ + int i; + + for (i = 1; /* void */ ; i++) { + if (myflock(fd, lock_style, + MYFLOCK_OP_EXCLUSIVE | MYFLOCK_OP_NOWAIT) == 0) + return (0); + if (i >= var_flock_tries) + break; + rand_sleep(var_flock_delay * MILLION, var_flock_delay * MILLION / 2); + } + if (why) + vstring_sprintf(why, "unable to lock for exclusive access: %m"); + return (-1); +} |