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author | Eduardo Chappa <echappa@gmx.com> | 2013-02-03 00:59:38 -0700 |
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committer | Eduardo Chappa <echappa@gmx.com> | 2013-02-03 00:59:38 -0700 |
commit | 094ca96844842928810f14844413109fc6cdd890 (patch) | |
tree | e60efbb980f38ba9308ccb4fb2b77b87bbc115f3 /imap/src/osdep/unix/flocklnx.c | |
download | alpine-094ca96844842928810f14844413109fc6cdd890.tar.xz |
Initial Alpine Version
Diffstat (limited to 'imap/src/osdep/unix/flocklnx.c')
-rw-r--r-- | imap/src/osdep/unix/flocklnx.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/imap/src/osdep/unix/flocklnx.c b/imap/src/osdep/unix/flocklnx.c new file mode 100644 index 00000000..ca0112ac --- /dev/null +++ b/imap/src/osdep/unix/flocklnx.c @@ -0,0 +1,76 @@ +/* ======================================================================== + * Copyright 1988-2006 University of Washington + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * + * ======================================================================== + */ + +/* + * Program: Safe File Lock for Linux + * + * Author: Mark Crispin + * Networks and Distributed Computing + * Computing & Communications + * University of Washington + * Administration Building, AG-44 + * Seattle, WA 98195 + * Internet: MRC@CAC.Washington.EDU + * + * Date: 20 April 2005 + * Last Edited: 30 August 2006 + */ + +#undef flock + +#include <sys/vfs.h> +#ifndef NFS_SUPER_MAGIC +#define NFS_SUPER_MAGIC 0x6969 +#endif + +int safe_flock (int fd,int op) +{ + struct statfs sfbuf; + char tmp[MAILTMPLEN]; + int e; + int logged = 0; + /* Check for NFS because Linux 2.6 broke flock() on NFS. Instead of being + * a no-op, flock() on NFS now returns ENOLCK. Read + * https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=123415 + * for the gruesome details. + */ + /* check filesystem type */ + while ((e = fstatfs (fd,&sfbuf)) && (errno == EINTR)); + if (!e) switch (sfbuf.f_type) { + case NFS_SUPER_MAGIC: /* always a fast no-op on NFS */ + break; + default: /* allow on other filesystem types */ + /* do the lock */ + while (flock (fd,op)) switch (errno) { + case EINTR: /* interrupt */ + break; + case ENOLCK: /* lock table is full */ + sprintf (tmp,"File locking failure: %s",strerror (errno)); + mm_log (tmp,WARN); /* give the user a warning of what happened */ + if (!logged++) syslog (LOG_ERR,tmp); + /* return failure if non-blocking lock */ + if (op & LOCK_NB) return -1; + sleep (5); /* slow down in case it loops */ + break; + case EWOULDBLOCK: /* file is locked, LOCK_NB should be set */ + if (op & LOCK_NB) return -1; + case EBADF: /* not valid open file descriptor */ + case EINVAL: /* invalid operator */ + default: /* other error code? */ + sprintf (tmp,"Unexpected file locking failure: %s",strerror (errno)); + fatal (tmp); + } + break; + } + return 0; /* success */ +} |