[tarantool-patches] Re: [PATCH v2 2/2] say: take getaddrinfo() errors into account

[Roman Khabibov <roman.habibov@tarantool.org>]

> On Sep 6, 2019, at 16:44, Alexander Turenko <alexander.turenko@tarantool.org> wrote:
> 
>>>> +--
>>>> +-- gh-4138: check getaddrinfo() error and panic after that.
>>>> +--
>>>> +code=[[
>>>> +local socket = require('socket')
>>>> +local log = require('log')
>>>> +local fio = require('fio')
>>>> +
>>>> +path = fio.pathjoin(fio.cwd(), 'log_unix_socket_test.sock')
>>>> +unix_socket = socket('AF_UNIX', 'SOCK_DGRAM', 0)
>>>> +unix_socket:bind('unix/', path)
>>>> +
>>>> +opt = string.format("syslog:server=non_exists_hostname:%s,identity=tarantool", path)
>>>> +box.cfg{log = opt, log_nonblock=true}
>>> 
>>> log_nonblock is not needed here, so it is better to remove it.
>> Removed.
> 
> Still no.
> 
>>> box.cfg{log = 'syslog:server=non_exists_hostname:3301'} is enough, not need to
>>> form a file path, no need identity, no need requiring socket, log and fio.
>>> 
>>> The test passes even before the patch, so what it is intended to test? I
>>> think we should write a test that verifies stderr output to find all log
>>> messages we expect to appear in the case:
>>> 
>>> Linux:
>>> 
>>> | SystemError getaddrinfo: Temporary failure in name resolution: Input/output error
>>> | SystemError syslog logger: Input/output error: Input/output error
>>> | failed to initialize logging subsystem
>>> 
>>> gai_strerror() message corresponds to EAI_AGAIN.
>>> 
>>> Mac OS:
>>> 
>>> | SystemError getaddrinfo: nodename nor servname provided, or not known: Input/output error
>>> | SystemError syslog logger: Input/output error: Input/output error
>>> | failed to initialize logging subsystem
>>> 
>>> gai_strerror() message corresponds to EAI_NONAME.
>>> 
>>> I propose to call ffi.C.gai_strerror() right from a test to form two
>>> error messages and verify that the actual input match one of them.
>>> 
>>> If it is hard to catch stderr, then let's proceed w/o this test. However
>>> I think it is doable.
>>> 
>>> I also propose to test error messages in the similar way (using
>>> ffi.C.gai_strerror(GAI_AGAIN) and ffi.C.gai_strerror(GAI_NONAME)) in
>>> test cases in second patch of the patchset.
>> We discussed that with Vova and we decided, that it is too difficult.
>> It is better, to waste not time for this test. Test for PANIC is enough.
> 
> I don't see any reason to add a test case that checks that tarantool
> exits in the case: it was so before the commit and nothing is changed
> except the error message. I propose to delete the test case.
Ok. Removed.

>>>> +	/* gh-4138: Check getaddrinfo() error. */
>>>> +	isnt(coio_getaddrinfo("non_exists_hostname", port, NULL, &i, 1), 0,
>>>> +	     "getaddrinfo error");
>>> 
>>> I would say 'getaddrinfo retval' instead 'getaddrinfo error'.
> 
> I don't insist, but remind about that here if it was missed by a
> mistake.
+	/* gh-4138: Check getaddrinfo() retval. */
+	rc = coio_getaddrinfo("non_exists_hostname", port, NULL, &i, 1);
+	isnt(rc, 0, "getaddrinfo retval");
+	isnt(strstr(diag_get()->last->errmsg, "getaddrinfo"), NULL,
+	     "getaddrinfo error message");
+

>>>> +	isnt(strstr(diag_get()->last->errmsg, "getaddrinfo"), NULL,
>>>> +	     "getaddrinfo error message");
>>>> +
>>> 
>>> I propose to verify the entire error message using
>>> gai_strerror(GAI_AGAIN) and gai_strerror(GAI_NONAME)—just as proposed
>>> above for a log message.
>> I have not found the way, how to carry this macros/enum from the libc header to Lua.
> 
> It is possible to add them into socket.c, but anyway it is not worth to
> do this just for a test. Let's check for certain error messages (not for
> just 'getaddrinfo: ' prefix).

commit 3e973c2203131ab663bdf1154be73ff6592568ea
Author: Roman Khabibov <roman.habibov@tarantool.org>
Date:   Tue Jul 30 15:39:21 2019 +0300

    coiox/say: fix getaddrinfo error handling on macOS
    
    Before this patch, branch when getaddrinfo() returns error codes
    couldn't be reached on macOS, because they are greater than 0 on
    macOS (assumption "rc < 0" in commit ea1da04 is incorrect for
    macOS).
    
    Note: diag_log() in say.c was added, because otherwise it will be
    hid by the following diagnostic and then say that it should
    be handler in a better way after #1148. Also, two diag_set() in
    syslog_connect_unix() was added to avoid asserts in this
    diag_log().
    
    Need for #4138

diff --git a/src/lib/core/coio_task.c b/src/lib/core/coio_task.c
index 908b336ed..83f669d05 100644
--- a/src/lib/core/coio_task.c
+++ b/src/lib/core/coio_task.c
@@ -413,7 +413,7 @@ coio_getaddrinfo(const char *host, const char *port,
 		return -1; /* timed out or cancelled */
 
 	/* Task finished */
-	if (task->rc < 0) {
+	if (task->rc != 0) {
 		/* getaddrinfo() failed */
 		errno = EIO;
 		diag_set(SystemError, "getaddrinfo: %s",
diff --git a/src/lib/core/say.c b/src/lib/core/say.c
index 64a637c58..8ad88ad57 100644
--- a/src/lib/core/say.c
+++ b/src/lib/core/say.c
@@ -459,14 +459,17 @@ static inline int
 syslog_connect_unix(const char *path)
 {
 	int fd = socket(PF_UNIX, SOCK_DGRAM, 0);
-	if (fd < 0)
+	if (fd < 0) {
+		diag_set(SystemError, "socket");
 		return -1;
+	}
 	struct sockaddr_un un;
 	memset(&un, 0, sizeof(un));
 	snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
 	un.sun_family = AF_UNIX;
 	if (connect(fd, (struct sockaddr *) &un, sizeof(un)) != 0) {
 		close(fd);
+		diag_set(SystemError, "connect");
 		return -1;
 	}
 	return fd;
@@ -506,7 +509,7 @@ syslog_connect_remote(const char *server_address)
 	hints.ai_protocol = IPPROTO_UDP;
 
 	ret = getaddrinfo(remote, portnum, &hints, &inf);
-	if (ret < 0) {
+	if (ret != 0) {
 		errno = EIO;
 		diag_set(SystemError, "getaddrinfo: %s",
 			 gai_strerror(ret));
@@ -593,6 +596,11 @@ log_syslog_init(struct log *log, const char *init_str)
 	say_free_syslog_opts(&opts);
 	log->fd = log_syslog_connect(log);
 	if (log->fd < 0) {
+		/*
+		 * We need to log a diagnostics here until stacked
+		 * diagnostics will be implemented (#1148).
+		 */
+		diag_log();
 		/* syslog indent is freed in atexit(). */
 		diag_set(SystemError, "syslog logger: %s", strerror(errno));
 		return -1;
diff --git a/test/unit/coio.cc b/test/unit/coio.cc
index bb8bd7131..3758c8857 100644
--- a/test/unit/coio.cc
+++ b/test/unit/coio.cc
@@ -72,7 +72,7 @@ static void
 test_getaddrinfo(void)
 {
 	header();
-	plan(1);
+	plan(3);
 	const char *host = "127.0.0.1";
 	const char *port = "3333";
 	struct addrinfo *i;
@@ -81,6 +81,12 @@ test_getaddrinfo(void)
 	is(rc, 0, "getaddrinfo");
 	freeaddrinfo(i);
 
+	/* gh-4138: Check getaddrinfo() retval. */
+	rc = coio_getaddrinfo("non_exists_hostname", port, NULL, &i, 1);
+	isnt(rc, 0, "getaddrinfo retval");
+	isnt(strstr(diag_get()->last->errmsg, "getaddrinfo"), NULL,
+	     "getaddrinfo error message");
+
 	/*
 	 * gh-4209: 0 timeout should not be a special value and
 	 * detach a task. Before a fix it led to segfault
diff --git a/test/unit/coio.result b/test/unit/coio.result
index 5019fa48a..90b567140 100644
--- a/test/unit/coio.result
+++ b/test/unit/coio.result
@@ -7,6 +7,8 @@
 # call done with res 0
 	*** test_call_f: done ***
 	*** test_getaddrinfo ***
-1..1
+1..3
 ok 1 - getaddrinfo
+ok 2 - getaddrinfo retval
+ok 3 - getaddrinfo error message
 	*** test_getaddrinfo: done ***