asyn.h 6.6 KB

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  1. #ifndef HEADER_CURL_ASYN_H
  2. #define HEADER_CURL_ASYN_H
  3. /***************************************************************************
  4. * _ _ ____ _
  5. * Project ___| | | | _ \| |
  6. * / __| | | | |_) | |
  7. * | (__| |_| | _ <| |___
  8. * \___|\___/|_| \_\_____|
  9. *
  10. * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
  11. *
  12. * This software is licensed as described in the file COPYING, which
  13. * you should have received as part of this distribution. The terms
  14. * are also available at https://curl.haxx.se/docs/copyright.html.
  15. *
  16. * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  17. * copies of the Software, and permit persons to whom the Software is
  18. * furnished to do so, under the terms of the COPYING file.
  19. *
  20. * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  21. * KIND, either express or implied.
  22. *
  23. ***************************************************************************/
  24. #include "curl_setup.h"
  25. #include "curl_addrinfo.h"
  26. struct addrinfo;
  27. struct hostent;
  28. struct Curl_easy;
  29. struct connectdata;
  30. struct Curl_dns_entry;
  31. /*
  32. * This header defines all functions in the internal asynch resolver interface.
  33. * All asynch resolvers need to provide these functions.
  34. * asyn-ares.c and asyn-thread.c are the current implementations of asynch
  35. * resolver backends.
  36. */
  37. /*
  38. * Curl_resolver_global_init()
  39. *
  40. * Called from curl_global_init() to initialize global resolver environment.
  41. * Returning anything else than CURLE_OK fails curl_global_init().
  42. */
  43. int Curl_resolver_global_init(void);
  44. /*
  45. * Curl_resolver_global_cleanup()
  46. * Called from curl_global_cleanup() to destroy global resolver environment.
  47. */
  48. void Curl_resolver_global_cleanup(void);
  49. /*
  50. * Curl_resolver_init()
  51. * Called from curl_easy_init() -> Curl_open() to initialize resolver
  52. * URL-state specific environment ('resolver' member of the UrlState
  53. * structure). Should fill the passed pointer by the initialized handler.
  54. * Returning anything else than CURLE_OK fails curl_easy_init() with the
  55. * correspondent code.
  56. */
  57. CURLcode Curl_resolver_init(struct Curl_easy *easy, void **resolver);
  58. /*
  59. * Curl_resolver_cleanup()
  60. * Called from curl_easy_cleanup() -> Curl_close() to cleanup resolver
  61. * URL-state specific environment ('resolver' member of the UrlState
  62. * structure). Should destroy the handler and free all resources connected to
  63. * it.
  64. */
  65. void Curl_resolver_cleanup(void *resolver);
  66. /*
  67. * Curl_resolver_duphandle()
  68. * Called from curl_easy_duphandle() to duplicate resolver URL-state specific
  69. * environment ('resolver' member of the UrlState structure). Should
  70. * duplicate the 'from' handle and pass the resulting handle to the 'to'
  71. * pointer. Returning anything else than CURLE_OK causes failed
  72. * curl_easy_duphandle() call.
  73. */
  74. CURLcode Curl_resolver_duphandle(struct Curl_easy *easy, void **to,
  75. void *from);
  76. /*
  77. * Curl_resolver_cancel().
  78. *
  79. * It is called from inside other functions to cancel currently performing
  80. * resolver request. Should also free any temporary resources allocated to
  81. * perform a request. This never waits for resolver threads to complete.
  82. *
  83. * It is safe to call this when conn is in any state.
  84. */
  85. void Curl_resolver_cancel(struct connectdata *conn);
  86. /*
  87. * Curl_resolver_kill().
  88. *
  89. * This acts like Curl_resolver_cancel() except it will block until any threads
  90. * associated with the resolver are complete. This never blocks for resolvers
  91. * that do not use threads. This is intended to be the "last chance" function
  92. * that cleans up an in-progress resolver completely (before its owner is about
  93. * to die).
  94. *
  95. * It is safe to call this when conn is in any state.
  96. */
  97. void Curl_resolver_kill(struct connectdata *conn);
  98. /* Curl_resolver_getsock()
  99. *
  100. * This function is called from the multi_getsock() function. 'sock' is a
  101. * pointer to an array to hold the file descriptors, with 'numsock' being the
  102. * size of that array (in number of entries). This function is supposed to
  103. * return bitmask indicating what file descriptors (referring to array indexes
  104. * in the 'sock' array) to wait for, read/write.
  105. */
  106. int Curl_resolver_getsock(struct connectdata *conn, curl_socket_t *sock);
  107. /*
  108. * Curl_resolver_is_resolved()
  109. *
  110. * Called repeatedly to check if a previous name resolve request has
  111. * completed. It should also make sure to time-out if the operation seems to
  112. * take too long.
  113. *
  114. * Returns normal CURLcode errors.
  115. */
  116. CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
  117. struct Curl_dns_entry **dns);
  118. /*
  119. * Curl_resolver_wait_resolv()
  120. *
  121. * Waits for a resolve to finish. This function should be avoided since using
  122. * this risk getting the multi interface to "hang".
  123. *
  124. * If 'entry' is non-NULL, make it point to the resolved dns entry
  125. *
  126. * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved,
  127. * CURLE_OPERATION_TIMEDOUT if a time-out occurred, or other errors.
  128. */
  129. CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
  130. struct Curl_dns_entry **dnsentry);
  131. /*
  132. * Curl_resolver_getaddrinfo() - when using this resolver
  133. *
  134. * Returns name information about the given hostname and port number. If
  135. * successful, the 'hostent' is returned and the forth argument will point to
  136. * memory we need to free after use. That memory *MUST* be freed with
  137. * Curl_freeaddrinfo(), nothing else.
  138. *
  139. * Each resolver backend must of course make sure to return data in the
  140. * correct format to comply with this.
  141. */
  142. Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
  143. const char *hostname,
  144. int port,
  145. int *waitp);
  146. #ifndef CURLRES_ASYNCH
  147. /* convert these functions if an asynch resolver isn't used */
  148. #define Curl_resolver_cancel(x) Curl_nop_stmt
  149. #define Curl_resolver_kill(x) Curl_nop_stmt
  150. #define Curl_resolver_is_resolved(x,y) CURLE_COULDNT_RESOLVE_HOST
  151. #define Curl_resolver_wait_resolv(x,y) CURLE_COULDNT_RESOLVE_HOST
  152. #define Curl_resolver_getsock(x,y,z) 0
  153. #define Curl_resolver_duphandle(x,y,z) CURLE_OK
  154. #define Curl_resolver_init(x,y) CURLE_OK
  155. #define Curl_resolver_global_init() CURLE_OK
  156. #define Curl_resolver_global_cleanup() Curl_nop_stmt
  157. #define Curl_resolver_cleanup(x) Curl_nop_stmt
  158. #endif
  159. #ifdef CURLRES_ASYNCH
  160. #define Curl_resolver_asynch() 1
  161. #else
  162. #define Curl_resolver_asynch() 0
  163. #endif
  164. /********** end of generic resolver interface functions *****************/
  165. #endif /* HEADER_CURL_ASYN_H */