104 lines
2.5 KiB
C
104 lines
2.5 KiB
C
/* unlock.c: The opieunlock() library function.
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%%% portions-copyright-cmetz-96
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Portions of this software are Copyright 1996-1997 by Craig Metz, All Rights
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Reserved. The Inner Net License Version 2 applies to these portions of
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the software.
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You should have received a copy of the license with this software. If
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you didn't get a copy, you may request one from <license@inner.net>.
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Portions of this software are Copyright 1995 by Randall Atkinson and Dan
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McDonald, All Rights Reserved. All Rights under this copyright are assigned
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to the U.S. Naval Research Laboratory (NRL). The NRL Copyright Notice and
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License Agreement applies to this software.
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History:
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Modified by cmetz for OPIE 2.31. Bug fix.
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Modified by cmetz for OPIE 2.3. Do refcounts whether or not
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we actually lock. Fixed USER_LOCKING=0 case.
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Modified by cmetz for OPIE 2.22. Added reference count support.
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Changed lock filename/refcount symbol names to better indicate
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that they're not user serviceable.
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Modified by cmetz for OPIE 2.2. Use FUNCTION declaration.
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Check for read() == -1. ifdef around unistd.h.
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Created at NRL for OPIE 2.2 from opiesubr2.c
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*/
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#include "opie_cfg.h"
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#include <string.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif /* HAVE_UNISTD_H */
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#include <fcntl.h>
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#include "opie.h"
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extern int __opie_lockrefcount;
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#if USER_LOCKING
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extern char *__opie_lockfilename;
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#endif /* USER_LOCKING */
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/*
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Just remove the lock, right?
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Well, not exactly -- we need to make sure it's ours.
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*/
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int opieunlock FUNCTION_NOARGS
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{
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#if USER_LOCKING
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int fh, rval = -1, pid, t, i;
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char buffer[128], *c, *c2;
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if (--__opie_lockrefcount > 0)
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return 0;
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if (!__opie_lockfilename)
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return -1;
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if (!(fh = open(__opie_lockfilename, O_RDWR, 0600)))
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goto unlockret;
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if ((i = read(fh, buffer, sizeof(buffer))) < 0)
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goto unlockret;
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buffer[sizeof(buffer) - 1] = 0;
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buffer[i - 1] = 0;
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if (!(c = strchr(buffer, '\n')))
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goto unlockret;
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*(c++) = 0;
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if (!(c2 = strchr(c, '\n')))
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goto unlockret;
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*(c2++) = 0;
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if (!(pid = atoi(buffer)))
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goto unlockret;
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if (!(t = atoi(c)))
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goto unlockret;
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if ((pid != getpid()) && (time(0) <= OPIE_LOCK_TIMEOUT + t) && (!kill(pid, 0))) {
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rval = 1;
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goto unlockret1;
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}
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rval = 0;
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unlockret:
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unlink(__opie_lockfilename);
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unlockret1:
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if (fh)
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close(fh);
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free(__opie_lockfilename);
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__opie_lockfilename = NULL;
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return rval;
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#else /* USER_LOCKING */
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if (__opie_lockrefcount-- > 0)
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return 0;
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return -1;
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#endif /* USER_LOCKING */
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}
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