File 0001-mount-swap-cryptsetup-introduce-an-option-... of Package systemd-mini

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File 0001-mount-swap-cryptsetup-introduce-an-option-to-prevent.patch of Package systemd-mini

From c61c3e2ac903e6c8a53d0e70ec04eb0fe3a58fd6 Mon Sep 17 00:00:00 2001
From: Franck Bui <fbui@suse.com>
Date: Thu, 31 Oct 2019 18:32:08 +0100
Subject: [PATCH 1/1] mount/swap/cryptsetup: introduce an option to prevent
 systemd from making a unit wanted by its device unit

systemd introduced a behavior that consisted in activating automatically a unit
generated by either fstab-generator or cryptsetup-generator each time its
device unit is entering in plugged state and regardless of whether it happened
during the boot process or much later.

This behavior is confusing for a lot of users and interacts badly with tools
which are operating on block devices.

Fortunately this feature has been removed by upstream since v242 for both mount
and swap units, with commits 142b8142d7bb84f07ac33fc00527a4d48ac8ef9f and
9b88bb5023dfa3cea406c14fdaa3d8e3e320907a respectively.

However for backward compatibility reasons we can't simply drop it, therefore
this patch introduces a new (but temporary) kernel command line option named
'systemd.device_wants_unit' so one can choose to prevent systemd from starting
automagically a unit which was generated by {cryptsetup,fstab}-generator by
setting it to 'off'.

The default value for this option is 'on' so no behavior change will happen by
default but please note that next major versions of SLE will permanently switch
it to 'off' without any possibilities to change it.

With this option enabled, it's now possible to prevent all swap units to be
activated by masking the swap target.

[fbui: fixes jsc#SLE-7689]
---
 src/basic/proc-cmdline.c              | 15 +++++++++++++++
 src/basic/proc-cmdline.h              |  2 ++
 src/core/unit.c                       |  3 ++-
 src/cryptsetup/cryptsetup-generator.c |  8 +++++---
 4 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/basic/proc-cmdline.c b/src/basic/proc-cmdline.c
index 8592a428d5..3936e809b6 100644
--- a/src/basic/proc-cmdline.c
+++ b/src/basic/proc-cmdline.c
@@ -247,6 +247,21 @@ int shall_restore_state(void) {
         return r > 0 ? ret : true;
 }
 
+bool shall_device_want_unit(void) {
+        static int device_wants_unit = -1;
+
+        if (device_wants_unit < 0) {
+                bool ret;
+
+                if (proc_cmdline_get_bool("systemd.device_wants_unit", &ret) > 0)
+                        device_wants_unit = ret;
+                else
+                        device_wants_unit = true;
+        }
+
+        return device_wants_unit;
+}
+
 static const char * const rlmap[] = {
         "emergency", SPECIAL_EMERGENCY_TARGET,
         "-b",        SPECIAL_EMERGENCY_TARGET,
diff --git a/src/basic/proc-cmdline.h b/src/basic/proc-cmdline.h
index ebfed355e9..bb4ebe5ee7 100644
--- a/src/basic/proc-cmdline.h
+++ b/src/basic/proc-cmdline.h
@@ -52,3 +52,5 @@ static inline bool proc_cmdline_value_missing(const char *key, const char *value
 
         return false;
 }
+
+bool shall_device_want_unit(void);
diff --git a/src/core/unit.c b/src/core/unit.c
index febce9d242..736863e48c 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -46,6 +46,7 @@
 #include "mkdir.h"
 #include "parse-util.h"
 #include "path-util.h"
+#include "proc-cmdline.h"
 #include "process-util.h"
 #include "set.h"
 #include "signal-util.h"
@@ -3172,7 +3173,7 @@ int unit_add_node_link(Unit *u, const char *what, bool wants, UnitDependency dep
         if (r < 0)
                 return r;
 
-        if (wants) {
+        if (wants && shall_device_want_unit()) {
                 r = unit_add_dependency(device, UNIT_WANTS, u, false);
                 if (r < 0)
                         return r;
diff --git a/src/cryptsetup/cryptsetup-generator.c b/src/cryptsetup/cryptsetup-generator.c
index 312cdf3d1f..ce47f9f0da 100644
--- a/src/cryptsetup/cryptsetup-generator.c
+++ b/src/cryptsetup/cryptsetup-generator.c
@@ -195,9 +195,11 @@ static int create_disk(
                 return log_error_errno(r, "Failed to write file %s: %m", p);
 
         if (!noauto) {
-                r = generator_add_symlink(arg_dest, d, "wants", n);
-                if (r < 0)
-                        return r;
+                if (shall_device_want_unit()) {
+                        r = generator_add_symlink(arg_dest, d, "wants", n);
+                        if (r < 0)
+                                return r;
+                }
 
                 r = generator_add_symlink(arg_dest,
                                           netdev ? "remote-cryptsetup.target" : "cryptsetup.target",
-- 
2.16.4

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