Reconsider usages of `gethostbyname_r()`

[Girgias]

Description

According to some sources, this function is obsolete and should be replaced with:

Applications should use getaddrinfo(3), getnameinfo(3), and gai_strerror(3) instead.

Moreover, getting rid of them would allow us to get remove some conditionally defined globals:

php-src/ext/standard/file.h

Lines 106 to 110 in 69d9c12

	#ifdef HAVE_GETHOSTBYNAME_R
	struct hostent tmp_host_info;
	char *tmp_host_buf;
	size_t tmp_host_buf_len;
	#endif

Initially found while working on #15511

[devnexen]

yes, in the same vein of the previous inet_aton removals.

[NattyNarwhal]

Looks like we're wrapping both getaddrinfo and gethostbyname_(r) as php_network_getaddresses and php_network_gethostbyname respectively, with the former wrapping the latter if getaddrinfo doesn't exist.

It does seem that all the gethostbyname_r calls get wrapped by php_network_gethostbyname, but getaddrinfo usage in exts/SAPIs is inconsistent if it calls php_network_getaddresses or getaddrinfo directly.

For the functions like gethostbyaddr and gethostbyname PHP functions, they can probably be changed to call the better interface.

[NattyNarwhal]

As for getting rid of gethostbyaddr, it should simplify the build system, because the _r variant is non-standard with different number of parameters. getaddrinfo is in POSIX since 2004 and is in almost everything with an IPv6 stack (i.e. anything modern enough to run PHP on).

[NattyNarwhal]

I'm also realizing that PHP gethostbyname and friends are documented as returning v4 addresses only. We should probably make these return v6 addresses, or preserve the existing behaviour (even with backing function change) and offer a new function based around getaddrinfo that exposes everything it does (edit: or extend the existing interface in next release).

[Girgias]

Hum, looks there is quite a bit of cruft in that area.

Probably creating some new php_* functions, using those consistently, and deprecating the "old" php_* functions is the best step forward?

[NattyNarwhal]

I think php_network_getaddresses is probably OK as-is, and php_network_gethostbyname can act as a wrapper for it instead of the other way around to keep ABI compatibility (then we can remove php_network_gethostbyname in 8.5/9.0).

[cmb69]

According to some sources, this function is obsolete and should be replaced with:

On Windows I get:

main\network.c(1352,9): warning: 'gethostbyname' is deprecated: Use getaddrinfo() or GetAddrInfoW() instead or define _WINSOCK_DEPRECATED_NO_WARNINGS to disable deprecated API warnings [-Wdeprecated-declarations]
 1352 |         return gethostbyname(name);
      |                ^
C:\Program Files (x86)\Windows Kits\10\\include\10.0.22621.0\\um\winsock2.h(2221,1): note: 'gethostbyname' has been explicitly marked deprecated here
 2221 | _WINSOCK_DEPRECATED_BY("getaddrinfo() or GetAddrInfoW()")
      | ^
C:\Program Files (x86)\Windows Kits\10\\include\10.0.22621.0\\um\winsock2.h(26,56): note: expanded from macro '_WINSOCK_DEPRECATED_BY'
   26 | #define _WINSOCK_DEPRECATED_BY(replacement) __declspec(deprecated("Use " replacement " instead or define _WINSOCK_DEPRECATED_NO_WARNINGS to disable deprecated API warnings"))
      |                                                        ^