Hi Timo,
I am running Dovecot 2.4.4 under FreeBSD 15.x, and I noticed that the IMAP
hibernation feature fails to work natively on this platform.
The Problem
Under FreeBSD, running fstat() on a network socket
returns NODEV (UINT64_MAX or 18446744073709551615) for
both major()and minor() device numbers.
When imap-hibernate tries to serialize these values, they are printed as
64-bit unsigned integers. However, Dovecot's internal parser
in imap-master-client.c uses standard 32-bit integers (unsigned int)
and str_to_uint(). This causes an integer overflow, triggering the
following error during hibernation: Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
The Solution
I've created a patch for src/imap/imap-master-client.c that scales the
parser variables to uint64_t and switches the parsing function
to str_to_uint64(). Additionally, it updates the verification assertion to
prevent BUG crashes due to the expected dev_tbehavior of virtual network
sockets under FreeBSD.
Here is the combined patch that fixes the issue completely:
Fragment ot kod
--- src/imap/imap-master-client.c.orig 2026-05-12 10:48:57 UTC
+++ src/imap/imap-master-client.c
@@ -75,7 +75,7 @@ imap_master_client_parse_input(const char *const *args
const char **error_r)
{
const char *key, *value;
- unsigned int peer_dev_major = 0, peer_dev_minor = 0;
+ uint64_t peer_dev_major = 0, peer_dev_minor = 0;
i_zero(input_r);
i_zero(stats_r);
@@ -128,13 +128,13 @@ imap_master_client_parse_input(const char *const *args
return -1;
}
} else if (strcmp(key, "peer_dev_major") == 0) {
- if (str_to_uint(value, &peer_dev_major) < 0) {
+ if (str_to_uint64(value, &peer_dev_major) < 0) {
*error_r = t_strdup_printf(
"Invalid peer_dev_major value: %s",
value);
return -1;
}
} else if (strcmp(key, "peer_dev_minor") == 0) {
- if (str_to_uint(value, &peer_dev_minor) < 0) {
+ if (str_to_uint64(value, &peer_dev_minor) < 0) {
*error_r = t_strdup_printf(
"Invalid peer_dev_minor value: %s",
value);
return -1;
@@ -265,7 +265,7 @@ imap_master_client_parse_input(const char *const *args
}
if (peer_dev_major != 0 || peer_dev_minor != 0) {
master_input_r->peer_dev =
- makedev(peer_dev_major, peer_dev_minor);
+ makedev((unsigned long)peer_dev_major, (unsigned
long)peer_dev_minor);
}
return 0;
}
@@ -410,7 +410,8 @@ static int imap_master_client_verify(const struct imap
return -1;
}
if (peer_st.st_ino != master_input->peer_ino ||
- !CMP_DEV_T(peer_st.st_dev, master_input->peer_dev)) {
+ (!CMP_DEV_T(peer_st.st_dev, master_input->peer_dev) &&
+ major(peer_st.st_dev) != (unsigned long)-1)) {
*error_r = t_strdup_printf(
"BUG: Expected peer device=%lu,%lu inode=%s doesn't
match "
"client fd's actual device=%lu,%lu inode=%s",
Result
With this patch applied, hibernation works flawlessly under FreeBSD:
# doveadm who
username # service (pids) (ips)
[email protected] 1 imap (26000) (46.10.221.52)
[email protected] 2 imap-hibernate (26260) (46.10.221.52)
No error messages are logged by dovecot when it hibernates and restores
clients. I hope this can be integrated into the upstream code.
Best regards,
Jordan
On 25 Jun 2026, at 15:50, Jordan Ostrev <[email protected]> wrote:
Hi Timo,
i'm not programmer at all but here is my understanding of the problem:
In src/imap/imap-client-hibernate.c, the code serializes peer_dev_major and
peer_dev_minor using major() and minor() macros:
str_printfa(cmd, "\tpeer_dev_major=%lu\tpeer_dev_minor=%lu\tpeer_ino=%llu",
(unsigned long)major(peer_st.st_dev),
(unsigned long)minor(peer_st.st_dev),
(unsigned long long)peer_st.st_ino);
On FreeBSD, major() and minor() can return UINT64_MAX (18446744073709551615)
for file descriptors that are not block/character devices (such as sockets on
tmpfs/devfs). This value exceeds UINT_MAX and cannot be parsed by str_to_uint()
in imap-master-client.c, causing hibernation to fail.
On 25 Jun 2026, at 14:37, Jordan Ostrev <[email protected]> wrote:
Hi Timo,
I've made freebsd port patch which looks like that:
# cat files/patch-configure.ac
--- configure.ac.orig 2026-06-25 11:03:42 UTC
+++ configure.ac
@@ -363,7 +363,7 @@ AS_CASE(
DOVECOT_IOLOOP
DOVECOT_NOTIFY
AS_CASE(
- ["$notify"],
+ ["$have_notify"],
[none], [BUILD_IMAP_HIBERNATE=0],
[kqueue], [BUILD_IMAP_HIBERNATE=0],
[BUILD_IMAP_HIBERNATE=1])
I'm simulating the situation with telnet:
c idle
+ idling
* 4228 EXPUNGE
* 0 RECENT
* OK Still here
* OK Still here
* 4228 EXISTS
* 1 RECENT
* 4228 EXPUNGE
* 0 RECENT
* 4228 EXISTS
* 1 RECENT
* 4228 EXPUNGE
* 0 RECENT
* OK Still here
* OK Still here
* OK Still here
* OK Still here
* 4228 EXISTS
* 1 RECENT
* 4228 EXPUNGE
* 0 RECENT
* OK Still here
* OK Still here
d idle
c BAD Idle completed.
+ idling
* OK Still here
* 4228 EXISTS
* 1 RECENT
* 4228 EXPUNGE
* 0 RECENT
* OK Still here
* 4228 EXISTS
* 4227 FETCH (FLAGS (\Seen $NotJunk NotJunk))
* 4228 EXPUNGE
* OK Still here
in the log I see following:
Jun 25 14:21:17 classic dovecot[29292]: imap-hibernate: Error: conn
unix:imap-hibernate (uid=125): Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
Jun 25 14:21:17 classic dovecot[29292]:
imap([email protected])<29454><CLP/EhJVqIguCt00>: Error: Couldn't
hibernate imap client: /var/run/dovecot/imap-hibernate returned
failure: Failed to parse client input: Invalid peer_dev_major value:
18446744073709551615
Jun 25 14:21:17 classic dovecot[29292]: imap-hibernate: Error: conn
unix:imap-hibernate (uid=125): Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
Jun 25 14:21:17 classic dovecot[29292]:
imap([email protected])<30943><EJZELRJVp5QuCt00>: Error: Couldn't
hibernate imap client: /var/run/dovecot/imap-hibernate returned
failure: Failed to parse client input: Invalid peer_dev_major value:
18446744073709551615
Jun 25 14:26:03 classic dovecot[29292]: imap-hibernate: Error: conn
unix:imap-hibernate (uid=125): Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
Jun 25 14:26:03 classic dovecot[29292]:
imap([email protected])<30943><EJZELRJVp5QuCt00>: Error: Couldn't
hibernate imap client: /var/run/dovecot/imap-hibernate returned
failure: Failed to parse client input: Invalid peer_dev_major value:
18446744073709551615
Jun 25 14:26:03 classic dovecot[29292]: imap-hibernate: Error: conn
unix:imap-hibernate (uid=125): Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
Jun 25 14:26:03 classic dovecot[29292]:
imap([email protected])<29454><CLP/EhJVqIguCt00>: Error: Couldn't
hibernate imap client: /var/run/dovecot/imap-hibernate returned
failure: Failed to parse client input: Invalid peer_dev_major value:
18446744073709551615
Jun 25 14:29:28 classic dovecot[29292]: imap-hibernate: Error: conn
unix:imap-hibernate (uid=125): Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
Jun 25 14:29:28 classic dovecot[29292]:
imap([email protected])<29454><CLP/EhJVqIguCt00>: Error: Couldn't
hibernate imap client: /var/run/dovecot/imap-hibernate returned
failure: Failed to parse client input: Invalid peer_dev_major value:
18446744073709551615
Jun 25 14:33:36 classic dovecot[29292]: imap-hibernate: Error: conn
unix:imap-hibernate (uid=125): Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
Jun 25 14:33:36 classic dovecot[29292]:
imap([email protected])<33114><cX5QWRJVrZguCt00>: Error: Couldn't
hibernate imap client: /var/run/dovecot/imap-hibernate returned
failure: Failed to parse client input: Invalid peer_dev_major value:
18446744073709551615
Jun 25 14:33:37 classic dovecot[29292]: imap-hibernate: Error: conn
unix:imap-hibernate (uid=125): Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
Jun 25 14:33:37 classic dovecot[29292]:
imap([email protected])<33112><NlVOWRJVkbEuCt00>: Error: Couldn't
hibernate imap client: /var/run/dovecot/imap-hibernate returned
failure: Failed to parse client input: Invalid peer_dev_major value:
18446744073709551615
Jun 25 14:34:40 classic dovecot[29292]: imap-hibernate: Error: conn
unix:imap-hibernate (uid=125): Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
Jun 25 14:34:40 classic dovecot[29292]:
imap([email protected])<33112><NlVOWRJVkbEuCt00>: Error: Couldn't
hibernate imap client: /var/run/dovecot/imap-hibernate returned
failure: Failed to parse client input: Invalid peer_dev_major value:
18446744073709551615
Here is my piece of my config:
# dovecot -a | grep hibernate
imap_hibernate_timeout = 1 mins
service imap-hibernate {
unix_listener imap-hibernate {
What we can do more?
KR,
Jordan
On 25 Jun 2026, at 12:34, Timo Sirainen <[email protected]> wrote:
On 24. Jun 2026, at 21.34, Jordan Ostrev via dovecot
<[email protected]> wrote:
Hi,
IMAP hibernation compiles and attempts to run on FreeBSD 15.x
(tested with
Dovecot 2.4.4 and FreeBSD 15.1), but fails at runtime with:
plain
imap-hibernate: Error: conn unix:imap-hibernate (uid=125): Failed
to parse client input: Invalid peer_dev_major value:
18446744073709551615
Jun 24 21:27:08 classic dovecot[36888]: imap-hibernate: Error:
conn unix:imap-hibernate (uid=125): Failed to parse client input:
Invalid peer_dev_major value: 18446744073709551615
Jun 24 21:27:08 classic dovecot[36888]:
imap([email protected])<37120><ExaV/gNVAdt/AAAB>: Error:
Couldn't hibernate imap client: /var/run/dovecot/imap-hibernate
returned failure: Failed to parse client input: Invalid
peer_dev_major value: 18446744073709551615
..
1. Disable hibernation at compile time for kqueue systems, or
It was already supposed to be done, but looks like there's a bug.
Can you verify if this works? :
diff --git a/configure.ac b/configure.ac
index 9beacaa299..04f9c8edd6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -363,7 +363,7 @@ DOVECOT_TYPEOF
DOVECOT_IOLOOP
DOVECOT_NOTIFY
AS_CASE(
- ["$notify"],
+ ["$have_notify"],
[none], [BUILD_IMAP_HIBERNATE=0],
[kqueue], [BUILD_IMAP_HIBERNATE=0],
[BUILD_IMAP_HIBERNATE=1])
_______________________________________________
dovecot mailing list -- [email protected]
To unsubscribe send an email to [email protected]
