Mercurial > hg > octave-kai > gnulib-hg
annotate lib/canon-host.c @ 5934:fe449ec53f0d
* canon-host.c (canon-host): Append trailing "," to 0 in
initializer of struct addrinfo, as an indication that we don't
care how many members the structure has.
| author | Paul Eggert <eggert@cs.ucla.edu> |
|---|---|
| date | Fri, 24 Jun 2005 17:30:33 +0000 |
| parents | a48fb0e98c8c |
| children | 85d0a6143cc4 |
| rev | line source |
|---|---|
| 548 | 1 /* Host name canonicalization |
| 2 | |
|
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* canon-host.c (canon-host): Append trailing "," to 0 in
Paul Eggert <eggert@cs.ucla.edu>
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3 Copyright (C) 1995, 1999, 2000, 2002, 2003, 2004, 2005 Free Software |
| 5458 | 4 Foundation, Inc. |
| 548 | 5 |
| 6 Written by Miles Bader <miles@gnu.ai.mit.edu> | |
| 7 | |
| 8 This program is free software; you can redistribute it and/or | |
| 9 modify it under the terms of the GNU General Public License as | |
| 10 published by the Free Software Foundation; either version 2, or (at | |
| 11 your option) any later version. | |
| 12 | |
| 13 This program is distributed in the hope that it will be useful, but | |
| 14 WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 16 General Public License for more details. | |
| 17 | |
| 18 You should have received a copy of the GNU General Public License | |
|
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19 along with this program; if not, write to the Free Software Foundation, |
|
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20 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ |
| 548 | 21 |
| 22 #ifdef HAVE_CONFIG_H | |
| 653 | 23 # include <config.h> |
| 548 | 24 #endif |
| 25 | |
|
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26 #include <sys/types.h> |
| 548 | 27 #ifdef HAVE_UNISTD_H |
| 653 | 28 # include <unistd.h> |
| 548 | 29 #endif |
| 4635 | 30 #include <stdlib.h> |
| 31 #include <string.h> | |
| 548 | 32 #ifdef HAVE_NETDB_H |
| 653 | 33 # include <netdb.h> |
| 548 | 34 #endif |
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35 #ifdef HAVE_SYS_SOCKET_H |
| 653 | 36 # include <sys/socket.h> |
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37 #endif |
| 548 | 38 |
| 39 #ifdef HAVE_NETINET_IN_H | |
| 653 | 40 # include <netinet/in.h> |
| 548 | 41 #endif |
| 42 #ifdef HAVE_ARPA_INET_H | |
| 653 | 43 # include <arpa/inet.h> |
| 548 | 44 #endif |
| 45 | |
| 5458 | 46 #include "strdup.h" |
| 47 | |
| 548 | 48 /* Returns the canonical hostname associated with HOST (allocated in a static |
| 5458 | 49 buffer), or NULL if it can't be determined. */ |
| 548 | 50 char * |
| 5458 | 51 canon_host (char const *host) |
| 548 | 52 { |
| 5458 | 53 char *h_addr_copy = NULL; |
| 548 | 54 |
| 5458 | 55 #if HAVE_GETADDRINFO |
| 56 { | |
|
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* canon-host.c (canon-host): Append trailing "," to 0 in
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57 struct addrinfo hint = { 0, }; |
| 5458 | 58 struct addrinfo *res = NULL; |
| 59 hint.ai_flags = AI_CANONNAME; | |
| 60 if (getaddrinfo (host, NULL, &hint, &res) == 0) | |
| 61 { | |
| 62 h_addr_copy = strdup (res->ai_canonname); | |
| 63 freeaddrinfo (res); | |
| 64 } | |
| 65 } | |
| 66 #elif HAVE_GETHOSTBYNAME | |
| 67 { | |
| 68 struct hostent *he = gethostbyname (host); | |
| 548 | 69 |
| 5458 | 70 if (he) |
| 71 { | |
| 72 # ifdef HAVE_GETHOSTBYADDR | |
| 73 char *addr = NULL; | |
| 74 | |
| 75 /* Try and get an ascii version of the numeric host address. */ | |
| 76 switch (he->h_addrtype) | |
| 77 { | |
| 653 | 78 # ifdef HAVE_INET_NTOA |
| 5458 | 79 case AF_INET: |
| 80 addr = inet_ntoa (*(struct in_addr *) he->h_addr); | |
| 81 break; | |
| 653 | 82 # endif /* HAVE_INET_NTOA */ |
| 5458 | 83 } |
| 548 | 84 |
| 5458 | 85 if (addr && strcmp (he->h_name, addr) == 0) |
| 86 { | |
| 87 /* gethostbyname has returned a string representation of the IP | |
| 88 address, for example, "127.0.0.1". So now, look up the host | |
| 89 name via the address. Although it may seem reasonable to look | |
| 90 up the host name via the address, we must not pass `he->h_addr' | |
| 91 directly to gethostbyaddr because on some systems he->h_addr | |
| 92 is located in a static library buffer that is reused in the | |
| 93 gethostbyaddr call. Make a copy and use that instead. */ | |
| 94 h_addr_copy = (char *) malloc (he->h_length); | |
| 95 if (h_addr_copy == NULL) | |
| 96 he = NULL; | |
| 97 else | |
| 98 { | |
| 99 memcpy (h_addr_copy, he->h_addr, he->h_length); | |
| 100 he = gethostbyaddr (h_addr_copy, he->h_length, he->h_addrtype); | |
| 101 free (h_addr_copy); | |
| 102 } | |
| 103 } | |
| 653 | 104 # endif /* HAVE_GETHOSTBYADDR */ |
| 548 | 105 |
| 5458 | 106 if (he) |
| 107 h_addr_copy = strdup (he->h_name); | |
| 108 } | |
| 109 } | |
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110 #endif /* HAVE_GETHOSTBYNAME */ |
| 5458 | 111 |
| 112 return h_addr_copy; | |
| 548 | 113 } |
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114 |
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115 #ifdef TEST_CANON_HOST |
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116 int |
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117 main (int argc, char **argv) |
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118 { |
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119 int i; |
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120 for (i = 1; i < argc; i++) |
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121 { |
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122 char *s = canon_host (argv[i]); |
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123 printf ("%s: %s\n", argv[i], (s ? s : "<undef>")); |
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124 } |
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125 exit (0); |
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126 } |
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127 #endif /* TEST_CANON_HOST */ |