[1482] | 1 | /* This file is part of the Project Athena Global Message System. |
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| 2 | * Created by: Mark W. Eichin <eichin@athena.mit.edu> |
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| 3 | * $Source: /afs/dev.mit.edu/source/repository/athena/bin/gms/message_daemon.c,v $ |
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| 4 | * $Author: eichin $ |
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| 5 | * |
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| 6 | * Copyright (c) 1988 by the Massachusetts Institute of Technology. |
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| 7 | * For copying and distribution information, see the file |
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| 8 | * "mit-copyright.h". |
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| 9 | */ |
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| 10 | #include <mit-copyright.h> |
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| 11 | #ifndef lint |
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[1511] | 12 | static char rcsid_message_daemon_c[] = "$Header: /afs/dev.mit.edu/source/repository/athena/bin/gms/message_daemon.c,v 1.4 1988-10-12 04:06:11 eichin Exp $"; |
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[1482] | 13 | #endif lint |
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| 14 | |
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| 15 | #include "globalmessage.h" |
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[1491] | 16 | #ifndef GMS_SERVER_MESSAGE |
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| 17 | #define GMS_SERVER_MESSAGE "/site/Message" |
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| 18 | #endif /* GMS_SERVER_MESSAGE */ |
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[1482] | 19 | |
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| 20 | #include <fcntl.h> |
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| 21 | #include <errno.h> |
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| 22 | #include <sys/types.h> |
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| 23 | #include <sys/socket.h> |
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| 24 | #include <netinet/in.h> |
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| 25 | #include <sys/stat.h> |
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| 26 | |
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| 27 | /* |
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| 28 | * This version of the daemon is run out of inetd, with a conf line of: |
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| 29 | * globalmessage dgram udp wait unswitched nobody /etc/messaged messaged |
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| 30 | */ |
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| 31 | #include <syslog.h> |
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| 32 | char *error_message(); |
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| 33 | |
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[1511] | 34 | #define saddr_list(sin) (unsigned)sin[0],(unsigned)sin[1],(unsigned)sin[2],(unsigned)sin[3] |
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[1482] | 35 | main(argc,argv) |
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| 36 | int argc; |
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| 37 | char **argv; |
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| 38 | { |
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| 39 | char buf[BFSZ]; |
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| 40 | int readstat, errstat, readlen, msgfile; |
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| 41 | char *index(); |
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| 42 | struct sockaddr from; |
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| 43 | /* these strange casts are so that I can print out the address of |
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| 44 | * the incoming packet. |
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| 45 | */ |
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| 46 | struct sockaddr_in *cast1 = (struct sockaddr_in *)&from; |
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| 47 | char *cast2 = (char *)(&(cast1->sin_addr.s_addr)); |
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| 48 | int fromlen = sizeof(from); |
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| 49 | time_t timestamp; |
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| 50 | int headerlen; |
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| 51 | |
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| 52 | /* initialize syslog connection for DAEMON */ |
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| 53 | /* log_pid has the side effect of forcing log messages to be unique, |
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| 54 | * not listed as ``message the same, repeated 6 times'' but that |
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| 55 | * shouldn't be a problem. |
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| 56 | */ |
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| 57 | openlog(argv[0], LOG_PID, LOG_DAEMON); |
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| 58 | |
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| 59 | /* gms is just return values; the other com_err tables used will |
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| 60 | * init themselves. |
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| 61 | */ |
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| 62 | init_gms_err_tbl(); |
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| 63 | |
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| 64 | /* read the packet from the socket (stdin, since we run from inetd) |
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| 65 | * and also record the from address so we can send a reply. |
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| 66 | */ |
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| 67 | readstat = recvfrom(0, buf, BFSZ, 0, &from, &fromlen); |
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| 68 | if(readstat == -1) { |
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| 69 | syslog(LOG_INFO, "GMS daemon recvfrom failure %s", error_message(errno)); |
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| 70 | exit(errno); |
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| 71 | } |
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| 72 | |
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| 73 | /* We got a packet successfully, so if logging is enabled record the |
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| 74 | * requesting address. |
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| 75 | */ |
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| 76 | if(argc>1 && !strcmp(argv[1],"-log")) { |
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[1511] | 77 | syslog(LOG_INFO, "GMS request succeeded [%s] from %ud.%ud.%ud.%ud", |
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[1482] | 78 | buf, saddr_list(cast2)); |
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| 79 | } |
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| 80 | |
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| 81 | /* Check the version number, and log if it is in error. */ |
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| 82 | if(strncmp(buf, GMS_VERSION_STRING, GMS_VERSION_STRING_LEN)) { |
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[1511] | 83 | syslog(LOG_INFO, "GMS bogus version [%s] from %ud.%ud.%ud.%ud", |
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[1482] | 84 | buf, saddr_list(cast2)); |
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| 85 | exit(GMS_CLIENT_VERSION); |
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| 86 | } |
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| 87 | |
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| 88 | /* Open the message file to read it in. Note that even were we to |
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| 89 | * want to cache the data for efficiency, we must stat the file to |
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| 90 | * make sure it hasn't changed under us. Since we're running, we |
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| 91 | * must open it because we have no state. |
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| 92 | */ |
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| 93 | msgfile = open(GMS_SERVER_MESSAGE, O_RDONLY, 0); |
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| 94 | |
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| 95 | if(msgfile == -1) { |
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| 96 | /* no file, special case of 0 timestamp indicating to also delete |
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| 97 | * the remote cached copy. If the error is ENOENT, then we just |
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| 98 | * assume it is an expected disappearance; all other errors are |
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| 99 | * `interesting' and are logged. In any case, the tester can see |
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| 100 | * that there is no new message. |
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| 101 | */ |
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| 102 | if(errno == ENOENT) { |
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| 103 | /* it didn't exist, we can deal with that... */ |
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| 104 | timestamp = 0; |
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| 105 | } else { |
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| 106 | /* something went wrong, but we can't do much about it; |
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| 107 | * let's not trash the remote state -- just don't answer the |
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| 108 | * connection. |
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| 109 | */ |
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| 110 | syslog(LOG_INFO, "GMS daemon open error [%s] reading message file <%s>", |
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| 111 | error_message(errno), GMS_SERVER_MESSAGE); |
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| 112 | exit(errno); |
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| 113 | } |
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| 114 | } else { |
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| 115 | struct stat sbuf; |
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| 116 | |
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| 117 | fstat(msgfile, &sbuf); |
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| 118 | if(sbuf.st_size == 0) { |
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| 119 | /* an empty file means the same to the remote as a missing one. */ |
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| 120 | timestamp = 0; |
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| 121 | } else { |
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| 122 | /* for convenient maintenance, use the real timestamp as version |
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| 123 | * number. */ |
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| 124 | timestamp = sbuf.st_mtime; |
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| 125 | } |
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| 126 | } |
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| 127 | strcpy(buf,GMS_VERSION_STRING); |
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| 128 | { |
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| 129 | char tsbuf[GMS_TIMESTAMP_LEN]; |
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| 130 | |
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| 131 | /* sprintf (and _doprnt in general) are slow memory hogs. However, |
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| 132 | * syslog is already including _doprnt, so it's already over; it |
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| 133 | * is cheaper just to use sprintf here instead of coding or |
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| 134 | * linking in the fast integer one. |
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| 135 | * It is almost readable, too... |
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| 136 | */ |
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| 137 | sprintf(tsbuf, " %lu\n", timestamp); |
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| 138 | strcat(buf,tsbuf); |
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| 139 | headerlen = strlen(buf); |
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| 140 | } |
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| 141 | |
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| 142 | /* Now that we have the header, we have to read the rest of the file |
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| 143 | * into the packet after it. The length-1 specification is to |
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[1489] | 144 | * preserve a NUL at the end of the buffer. Use msgfile to remember |
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| 145 | * that we couldn't open it. |
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[1482] | 146 | */ |
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[1489] | 147 | if(msgfile != -1) { |
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| 148 | readlen = read(msgfile, buf + headerlen, BFSZ-headerlen-1); |
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| 149 | if(readlen == -1) { |
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| 150 | /* read failed but open didn't, so record the error */ |
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| 151 | syslog(LOG_INFO, "GMS daemon read error [%s] reading message file <%s>", |
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| 152 | error_message(errno), GMS_SERVER_MESSAGE); |
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| 153 | exit(errno); |
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| 154 | } |
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| 155 | /* protect the fencepost... */ |
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| 156 | buf[BFSZ-1] = '\0'; |
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| 157 | close(msgfile); |
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[1482] | 158 | } |
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| 159 | /* send the packet back where it came from */ |
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| 160 | if(-1 == sendto(0, buf, readlen+headerlen, 0, &from, sizeof(from))) { |
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| 161 | /* the send failed (probably a local error, or bad address or |
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| 162 | * something so log the attempt. |
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| 163 | */ |
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| 164 | syslog(LOG_INFO, "GMS daemon sendto failure [%s] to %d.%d.%d.%d", |
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| 165 | error_message(errno), saddr_list(cast2)); |
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| 166 | exit(errno); |
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| 167 | } |
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| 168 | /* everything worked, die happy... */ |
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| 169 | exit(0); |
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| 170 | } |
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