Fails to build on arm{el,hf} with 64bit time_t: export-cache.c:110:51: error: format ‘%ld’ expects argument of type ‘long int’, but argument 4 has type ‘time_t’ {aka ‘long long int’} [-Werror=format=]

[Salvatore Bonaccorso <carnil@debian.org>]

[-- Attachment #1: Type: text/plain, Size: 4617 bytes --]

Hi Chuck, hi Steve,

In Debian, as you might have heard there is a 64bit time_t
transition[1] ongoing affecting the armel and armhf architectures.
While doing so, nfs-utils was found to fail to build for those
architectures after the switch, reported in Debian as [2]. Vladimir
Petko from Ubuntu has as well filled it in [3].

 [1]: https://lists.debian.org/debian-devel-announce/2024/02/msg00005.html
 [2]: https://bugs.debian.org/1067829
 [3]: https://bugzilla.kernel.org/show_bug.cgi?id=218540

The report is full-quoted below. 

Vladimir Petko has created a patch in the bugzilla which I'm attaching
here as well. If this is not an acceptable format due to missing
Signed-off's I'm attaching a variant with a Suggested-by for Vladimir
to properly credit the patch origin.

Let me know if that works. I changed it slightly and only casting to
long long, and made it almost checkpatch clean.

Regards,
Salvatore

----- Forwarded message from Sebastian Ramacher <sramacher@debian.org> -----

From: Sebastian Ramacher <sramacher@debian.org>
Resent-From: Sebastian Ramacher <sramacher@debian.org>
Reply-To: Sebastian Ramacher <sramacher@debian.org>, 1067829@bugs.debian.org
Date: Wed, 27 Mar 2024 11:02:25 +0100
To: Debian Bug Tracking System <submit@bugs.debian.org>
Subject: Bug#1067829: nfs-utils: FTBFS on arm{el,hf}: export-cache.c:110:51: error: format ‘%ld’ expects argument of
	type ‘long int’, but argument 4 has type ‘time_t’ {aka ‘long long int’} [-Werror=format=]
Delivered-To: submit@bugs.debian.org
Message-ID: <ZgPusfnkCCvhalve@ramacher.at>

Source: nfs-utils
Version: 1:2.6.4-3
Severity: serious
Tags: ftbfs
Justification: fails to build from source (but built successfully in the past)
X-Debbugs-Cc: sramacher@debian.org

https://buildd.debian.org/status/fetch.php?pkg=nfs-utils&arch=armel&ver=1%3A2.6.4-3%2Bb2&stamp=1711452552&raw=0

libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I../../support/include -I/usr/include/tirpc -I/usr/include/libxml2 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64 -Wdate-time -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -pipe -Wall -Wextra -Werror=strict-prototypes -Werror=missing-prototypes -Werror=missing-declarations -Werror=format=2 -Werror=undef -Werror=missing-include-dirs -Werror=strict-aliasing=2 -Werror=init-self -Werror=implicit-function-declaration -Werror=return-type -Werror=switch -Werror=overflow -Werror=parentheses -Werror=aggregate-return -Werror=unused-result -fno-strict-aliasing -Werror=format-overflow=2 -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=misleading-indentation -Wno-cast-function-type -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -c xml.c  -fPIC -DPIC -o .libs/xml.o
export-cache.c: In function ‘junction_flush_exports_cache’:
export-cache.c:110:51: error: format ‘%ld’ expects argument of type ‘long int’, but argument 4 has type ‘time_t’ {aka ‘long long int’} [-Werror=format=]
  110 |         snprintf(flushtime, sizeof(flushtime), "%ld\n", now);
      |                                                 ~~^     ~~~
      |                                                   |     |
      |                                                   |     time_t {aka long long int}
      |                                                   long int
      |                                                 %lld
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I../../support/include -I/usr/include/tirpc -I/usr/include/libxml2 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64 -Wdate-time -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -pipe -Wall -Wextra -Werror=strict-prototypes -Werror=missing-prototypes -Werror=missing-declarations -Werror=format=2 -Werror=undef -Werror=missing-include-dirs -Werror=strict-aliasing=2 -Werror=init-self -Werror=implicit-function-declaration -Werror=return-type -Werror=switch -Werror=overflow -Werror=parentheses -Werror=aggregate-return -Werror=unused-result -fno-strict-aliasing -Werror=format-overflow=2 -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=misleading-indentation -Wno-cast-function-type -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -c display.c -o display.o >/dev/null 2>&1
cc1: some warnings being treated as errors
make[3]: *** [Makefile:489: export-cache.lo] Error 1
make[3]: *** Waiting for unfinished jobs....

Cheers
-- 
Sebastian Ramacher

----- End forwarded message -----

[-- Attachment #2: armhf-time-t-format-error.patch --]
[-- Type: text/x-diff, Size: 715 bytes --]

Description: cast to a type with a known size to ensure sprintf works
Author: Vladimir Petko <vladimir.petko@canonical.com>
Bug: https://bugzilla.kernel.org/show_bug.cgi?id=218540
Bug-Ubuntu:  https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/2055349
Last-Update: 2024-02-29
--- a/support/junction/export-cache.c
+++ b/support/junction/export-cache.c
@@ -107,7 +107,7 @@
 		xlog(D_GENERAL, "%s: time(3) failed", __func__);
 		return FEDFS_ERR_SVRFAULT;
 	}
-	snprintf(flushtime, sizeof(flushtime), "%ld\n", now);
+	snprintf(flushtime, sizeof(flushtime), "%lld\n", (long long int)now);
 
 	for (i = 0; junction_proc_files[i] != NULL; i++) {
 		retval = junction_write_time(junction_proc_files[i], flushtime);

[-- Attachment #3: 0001-junction-export-cache-cast-to-a-type-with-a-known-si.patch --]
[-- Type: text/x-diff, Size: 3321 bytes --]

From 774394df352c249775d51d5d6e3effa775096b4f Mon Sep 17 00:00:00 2001
From: Salvatore Bonaccorso <carnil@debian.org>
Date: Sat, 6 Apr 2024 20:48:43 +0200
Subject: [PATCH] junction: export-cache: cast to a type with a known size to
 ensure sprintf works
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

As reported in Debian, with the 64bit time_t transition for the armel
and armhf architecture, it was found that nfs-utils fails to compile
with:

	libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I../../support/include -I/usr/include/tirpc -I/usr/include/libxml2 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64 -Wdate-time -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -pipe -Wall -Wextra -Werror=strict-prototypes -Werror=missing-prototypes -Werror=missing-declarations -Werror=format=2 -Werror=undef -Werror=missing-include-dirs -Werror=strict-aliasing=2 -Werror=init-self -Werror=implicit-function-declaration -Werror=return-type -Werror=switch -Werror=overflow -Werror=parentheses -Werror=aggregate-return -Werror=unused-result -fno-strict-aliasing -Werror=format-overflow=2 -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=misleading-indentation -Wno-cast-function-type -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -c xml.c  -fPIC -DPIC -o .libs/xml.o
	export-cache.c: In function ‘junction_flush_exports_cache’:
	export-cache.c:110:51: error: format ‘%ld’ expects argument of type ‘long int’, but argument 4 has type ‘time_t’ {aka ‘long long int’} [-Werror=format=]
	  110 |         snprintf(flushtime, sizeof(flushtime), "%ld\n", now);
	      |                                                 ~~^     ~~~
	      |                                                   |     |
	      |                                                   |     time_t {aka long long int}
	      |                                                   long int
	      |                                                 %lld

time_t is not guaranteed to be 64-bit, so it must be coerced into the expected
type for printf. Cast it to long long.

Reported-by: Vladimir Petko <vladimir.petko@canonical.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218540
Link: https://bugs.debian.org/1067829
Link: https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/2055349
Fixes: 494d22396d3d ("Add LDAP-free version of libjunction to nfs-utils")
Suggested-by: Vladimir Petko <vladimir.petko@canonical.com>
Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
---
 support/junction/export-cache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/support/junction/export-cache.c b/support/junction/export-cache.c
index 4e578c9b37b1..00187c019d60 100644
--- a/support/junction/export-cache.c
+++ b/support/junction/export-cache.c
@@ -107,7 +107,7 @@ junction_flush_exports_cache(void)
 		xlog(D_GENERAL, "%s: time(3) failed", __func__);
 		return FEDFS_ERR_SVRFAULT;
 	}
-	snprintf(flushtime, sizeof(flushtime), "%ld\n", now);
+	snprintf(flushtime, sizeof(flushtime), "%lld\n", (long long)now);
 
 	for (i = 0; junction_proc_files[i] != NULL; i++) {
 		retval = junction_write_time(junction_proc_files[i], flushtime);
-- 
2.43.0