gethostname.c 2.7 KB

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  1. /* gethostname emulation for SysV and POSIX.1.
  2. Copyright (C) 1992, 2003, 2006, 2008-2021 Free Software Foundation, Inc.
  3. This program is free software: you can redistribute it and/or modify
  4. it under the terms of the GNU Lesser General Public License as published by
  5. the Free Software Foundation; either version 3 of the License, or
  6. (at your option) any later version.
  7. This program is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  10. GNU Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public License
  12. along with this program. If not, see <https://www.gnu.org/licenses/>. */
  13. /* David MacKenzie <djm@gnu.ai.mit.edu>
  14. Windows port by Simon Josefsson <simon@josefsson.org> */
  15. #include <config.h>
  16. #if !(defined _WIN32 && !defined __CYGWIN__)
  17. /* Unix API. */
  18. /* Specification. */
  19. #include <unistd.h>
  20. #ifdef HAVE_UNAME
  21. # include <sys/utsname.h>
  22. #endif
  23. #include <string.h>
  24. /* Put up to LEN chars of the host name into NAME.
  25. Null terminate it if the name is shorter than LEN.
  26. Return 0 if ok, -1 if error. */
  27. #include <stddef.h>
  28. int
  29. gethostname (char *name, size_t len)
  30. {
  31. #ifdef HAVE_UNAME
  32. struct utsname uts;
  33. if (uname (&uts) == -1)
  34. return -1;
  35. if (len > sizeof (uts.nodename))
  36. {
  37. /* More space than we need is available. */
  38. name[sizeof (uts.nodename)] = '\0';
  39. len = sizeof (uts.nodename);
  40. }
  41. strncpy (name, uts.nodename, len);
  42. #else
  43. strcpy (name, ""); /* Hardcode your system name if you want. */
  44. #endif
  45. return 0;
  46. }
  47. #else
  48. /* Native Windows API. Which primitive to choose?
  49. - gethostname() requires linking with -lws2_32.
  50. - GetComputerName() does not return the right kind of hostname.
  51. - GetComputerNameEx(ComputerNameDnsHostname,...) returns the right hostname,
  52. but it is hard to use portably:
  53. - It requires defining _WIN32_WINNT to at least 0x0500.
  54. - With mingw, it also requires
  55. "#define GetComputerNameEx GetComputerNameExA".
  56. - With older versions of mingw, none of the declarations are present at
  57. all, not even of the enum value ComputerNameDnsHostname.
  58. So we use gethostname(). Linking with -lws2_32 is the least evil. */
  59. #define WIN32_LEAN_AND_MEAN
  60. /* Get winsock2.h. */
  61. #include <unistd.h>
  62. /* Get INT_MAX. */
  63. #include <limits.h>
  64. /* Get set_winsock_errno. */
  65. #include "w32sock.h"
  66. #include "sockets.h"
  67. #undef gethostname
  68. int
  69. rpl_gethostname (char *name, size_t len)
  70. {
  71. int r;
  72. if (len > INT_MAX)
  73. len = INT_MAX;
  74. gl_sockets_startup (SOCKETS_1_1);
  75. r = gethostname (name, (int) len);
  76. if (r < 0)
  77. set_winsock_errno ();
  78. return r;
  79. }
  80. #endif