5460 2007-12-09 04:33:00 +0000 glibc-2.6+ returns too many results from /etc/hosts in some cases 2008-07-07 20:44:38 +0000 1 1 1 Unclassified glibc libc unspecified All All RESOLVED INVALID P2 normal --- 4980 1 vapier drepper.fsp glibc-bugs tonnerre toolchain oldest_to_newest 20593 0 vapier 2007-12-09 04:33:57 +0000 if /etc/hosts looks like: 127.0.0.1 localhost localhost4 ::1 localhost localhost6 and you lookup "localhost6" with getaddrinfo(), the function returns "127.0.0.1" and "::1" glibc-2.5 and older operates correctly and only returns "::1". glibc-2.6 and newer will in addition incorrectly return "127.0.0.1". 20594 1 2128 vapier 2007-12-09 04:36:15 +0000 Created attachment 2128 getaddrinfo.c test case running this test case on newer glibc's will show: $ ./getaddrinfo localhost6 --- looking up 'localhost6' for family 0 (0) getaddrinfo(...) = EAI_NONAME, trying again with AI_CANONNAME getaddrinfo(...) = 0 getnameinfo(...) = 0 name = 127.0.0.1 service = 23 getnameinfo(...) = 0 name = ::1 service = 23 --- looking up 'localhost6' for family AF_INET (2) getaddrinfo(...) = EAI_NONAME, trying again with AI_CANONNAME getaddrinfo(...) = 0 getnameinfo(...) = 0 name = 127.0.0.1 service = 23 --- looking up 'localhost6' for family AF_INET6 (10) getaddrinfo(...) = EAI_NONAME, trying again with AI_CANONNAME getaddrinfo(...) = 0 getnameinfo(...) = 0 name = ::1 service = 23 on older glibc versions, that "127.0.0.1" entry wont crop up 22664 2 drepper.fsp 2008-04-07 16:34:59 +0000 Returning both entries is correct. It's the same in DNS: multiple entries are all returned. 22667 3 vapier 2008-04-07 17:45:46 +0000 looking up "localhost6" should never result in "127.0.0.1" 22732 4 drepper.fsp 2008-04-09 17:05:41 +0000 The code works as designed. This is no new change. Back in November 2006 I added code to map V6 addresses to v4 addresses in gethostbyname2(AF_INET) calls if it is possible. This is what happens here. The results are not wrong since you did not ask for a specific protocol. At some point, when we have unified lookup instead of separate IPv4/v6 lookups, this might change. But for now it works as expected and the program will work correctly. 22720 5 pasky 2008-04-09 17:25:53 +0000 It is not obvious that the design of the current code makes any sense, but looks like we will never get to know the reasons behind it... c.f. http://sourceware.org/bugzilla/show_bug.cgi?id=4980 2128 2007-12-09 04:36:00 +0000 2007-12-09 04:36:15 +0000 getaddrinfo.c test case getaddrinfo.c text/plain 1611 vapier I2RlZmluZSBfR05VX1NPVVJDRQojaW5jbHVkZSA8bmV0ZGIuaD4KI2luY2x1ZGUgPHN0ZGlvLmg+ CiNpbmNsdWRlIDxzdGRsaWIuaD4KI2luY2x1ZGUgPHN0cmluZy5oPgojaW5jbHVkZSA8YXJwYS9p bmV0Lmg+CiNpbmNsdWRlIDxuZXRpbmV0L2luLmg+CiNpbmNsdWRlIDxzeXMvc29ja2V0Lmg+CiNp bmNsdWRlIDxzeXMvdHlwZXMuaD4KCnZvaWQgZG9pdChjb25zdCBjaGFyICpuYW1lLCBjb25zdCBj aGFyICpmYW1pbHlfbmFtZSwgaW50IGZhbWlseSkKewoJcHJpbnRmKCItLS0gbG9va2luZyB1cCAn JXMnIGZvciBmYW1pbHkgJXMgKCVpKVxuIiwgbmFtZSwgZmFtaWx5X25hbWUsIGZhbWlseSk7CgoJ c3RydWN0IGFkZHJpbmZvIGhpbnRzOwoJbWVtc2V0KCZoaW50cywgMCwgc2l6ZW9mKGhpbnRzKSk7 CgloaW50cy5haV9zb2NrdHlwZSA9IFNPQ0tfU1RSRUFNOwoJaGludHMuYWlfZmxhZ3MgPSBBSV9O VU1FUklDSE9TVDsKCWhpbnRzLmFpX2ZhbWlseSA9IGZhbWlseTsKCglzdHJ1Y3QgYWRkcmluZm8g Kmhvc3RhZGRyID0gMDsKCWludCByZXMgPSBnZXRhZGRyaW5mbyhuYW1lLCAidGVsbmV0IiwgJmhp bnRzLCAmaG9zdGFkZHIpOwoJaWYgKHJlcyA9PSBFQUlfTk9OQU1FKSB7CgkJcHJpbnRmKCJnZXRh ZGRyaW5mbyguLi4pID0gRUFJX05PTkFNRSwgdHJ5aW5nIGFnYWluIHdpdGggQUlfQ0FOT05OQU1F XG4iKTsKCQloaW50cy5haV9mbGFncyA9IEFJX0NBTk9OTkFNRTsKCQlyZXMgPSBnZXRhZGRyaW5m byhuYW1lLCAidGVsbmV0IiwgJmhpbnRzLCAmaG9zdGFkZHIpOwoJfQoJaWYgKHJlcyA9PSBFQUlf Tk9OQU1FKSB7CgkJcHJpbnRmKCJnZXRhZGRyaW5mbyguLi4pID0gRUFJX05PTkFNRSAuLi4gRkFJ TFxuIik7Cgl9IGVsc2UgaWYgKHJlcykgewoJCXByaW50ZigiZ2V0YWRkcmluZm8oLi4uKSA9ICVp IC4uLiBGQUlMXG4iLCByZXMpOwoJfSBlbHNlIHsKCQlwcmludGYoImdldGFkZHJpbmZvKC4uLikg PSAlaVxuIiwgcmVzKTsKCgkJd2hpbGUgKGhvc3RhZGRyKSB7CgkJCWNoYXIgbmFtZVsxMDI0XSwg c2VydmljZVsxMDI0XTsKCQkJcmVzID0gZ2V0bmFtZWluZm8oaG9zdGFkZHItPmFpX2FkZHIsIGhv c3RhZGRyLT5haV9hZGRybGVuLAoJCQkJbmFtZSwgc2l6ZW9mKG5hbWUpLCBzZXJ2aWNlLCBzaXpl b2Yoc2VydmljZSksCgkJCQlOSV9OVU1FUklDSE9TVCB8IE5JX05VTUVSSUNTRVJWKTsKCQkJcHJp bnRmKCJnZXRuYW1laW5mbyguLi4pID0gJWlcbiIsIHJlcyk7CgkJCXByaW50ZigiXHRuYW1lID0g JXNcbiIsIG5hbWUpOwoJCQlwcmludGYoIlx0c2VydmljZSA9ICVzXG4iLCBzZXJ2aWNlKTsKCQkJ aG9zdGFkZHIgPSBob3N0YWRkci0+YWlfbmV4dDsKCQl9Cgl9CgoJZnJlZWFkZHJpbmZvKGhvc3Rh ZGRyKTsKfQoKaW50IG1haW4oaW50IGFyZ2MsIGNoYXIgKmFyZ3ZbXSkKewoJY29uc3QgY2hhciAq bmFtZSA9IChhcmdjID4gMSA/IGFyZ3ZbMV0gOiAibG9jYWxob3N0Iik7CgojZGVmaW5lIGRvaXQo bmFtZSwgZmFtaWx5KSBkb2l0KG5hbWUsICNmYW1pbHksIGZhbWlseSkKCWRvaXQobmFtZSwgMCk7 Cglkb2l0KG5hbWUsIEFGX0lORVQpOwoJZG9pdChuYW1lLCBBRl9JTkVUNik7CgoJcHV0cygiIik7 CgoJcmV0dXJuIDA7Cn0K