121 lines
3.5 KiB
C
121 lines
3.5 KiB
C
/* lock.c
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*
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* $Id$
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*
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* Copyright 1990, 1991, 1992, 1993, 1994, 1995, Oliver Laumann, Berlin
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* Copyright 2002, 2003 Sam Hocevar <sam@hocevar.net>, Paris
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*
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* This software was derived from Elk 1.2, which was Copyright 1987, 1988,
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* 1989, Nixdorf Computer AG and TELES GmbH, Berlin (Elk 1.2 has been written
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* by Oliver Laumann for TELES Telematic Services, Berlin, in a joint project
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* between TELES and Nixdorf Microprocessor Engineering, Berlin).
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*
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* Oliver Laumann, TELES GmbH, Nixdorf Computer AG and Sam Hocevar, as co-
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* owners or individual owners of copyright in this software, grant to any
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* person or company a worldwide, royalty free, license to
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*
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* i) copy this software,
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* ii) prepare derivative works based on this software,
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* iii) distribute copies of this software or derivative works,
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* iv) perform this software, or
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* v) display this software,
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*
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* provided that this notice is not removed and that neither Oliver Laumann
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* nor Teles nor Nixdorf are deemed to have made any representations as to
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* the suitability of this software for any purpose nor are held responsible
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* for any defects of this software.
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*
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* THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
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*/
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#include "unix.h"
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#include <sys/file.h>
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#ifdef F_SETLK
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# define LOCKS
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# define RECORD_LOCKS
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#else
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#ifdef LOCK_SH
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# define LOCKS
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#endif
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#endif
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#ifdef LOCKS
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static Object P_Internal_Lock_Operation(Object fd, Object lck, Object block,
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Object what, Object ret) {
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#ifdef RECORD_LOCKS
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struct flock fl;
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#else
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int mode;
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#endif
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int op;
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Object *vp;
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Check_Result_Vector(lck, 4);
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Check_Type(what, T_Character);
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op = CHAR(what);
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if (op == 'q')
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Check_Result_Vector(ret, 4);
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#ifdef RECORD_LOCKS
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Check_Type(block, T_Boolean);
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vp = VECTOR(lck)->data;
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Check_Type(*vp, T_Boolean);
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fl.l_type = op == 'r' ? F_UNLCK : (Truep(*vp) ? F_WRLCK : F_RDLCK);
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fl.l_whence = (short)Symbols_To_Bits(*++vp, 0, Lseek_Syms);
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fl.l_start = Get_Long(*++vp);
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fl.l_len = Get_Long(*++vp);
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if (fcntl(Get_Integer(fd), op == 'q' ? F_GETLK :
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(Truep(block) ? F_SETLKW : F_SETLK), &fl) == -1) {
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if (op == 's' && !Truep(block) && (errno == EAGAIN || errno == EACCES))
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return False;
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Raise_System_Error("fcntl: ~E");
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}
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if (op == 'q') {
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Object x;
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GC_Node;
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if (fl.l_type == F_UNLCK)
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return False;
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GC_Link(ret);
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VECTOR(ret)->data[0] = fl.l_type == F_WRLCK ? True : False;
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x = Bits_To_Symbols((unsigned long)fl.l_whence, 0, Lseek_Syms);
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VECTOR(ret)->data[1] = x;
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x = Make_Long(fl.l_start); VECTOR(ret)->data[2] = x;
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x = Make_Long(fl.l_len); VECTOR(ret)->data[3] = x;
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GC_Unlink;
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return Make_Integer(fl.l_pid);
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}
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#else
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Check_Type(block, T_Boolean);
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if (op == 'q')
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return False;
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vp = VECTOR(lck)->data;
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Check_Type(*vp, T_Boolean);
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mode = op == 'r' ? LOCK_UN : (Truep(*vp) ? LOCK_EX : LOCK_SH);
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if (op != 'r' && !Truep(block))
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mode |= LOCK_NB;
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if (flock(Get_Integer(fd), mode) == -1) {
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if (op == 's' && !Truep(block) && errno == EWOULDBLOCK)
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return False;
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Raise_System_Error("flock: ~E");
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}
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#endif
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return op == 's' ? True : Void;
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}
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#endif
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void elk_init_unix_lock() {
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#ifdef LOCKS
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Def_Prim(P_Internal_Lock_Operation, "unix-internal-lock-operation",
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5, 5, EVAL);
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P_Provide(Intern("unix:file-locking"));
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#ifdef RECORD_LOCKS
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P_Provide(Intern("unix:record-locks"));
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#endif
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#endif
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}
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