[systemd-devel] [PATCH] cryptsetup-generator: auto add deps for device as password

[Dave Reisner]

If the password is a device file, we can add Requires/After dependencies
on the device rather than requiring the user to do so.
---
This is based on a "bug" filed to Arch:

https://bugs.archlinux.org/task/38842

Assuming I'm correct about the race condition, this should be an easy way
of closing it without user involvement.

 src/cryptsetup/cryptsetup-generator.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/cryptsetup/cryptsetup-generator.c b/src/cryptsetup/cryptsetup-generator.c
index 9c98f0b..4542757 100644
--- a/src/cryptsetup/cryptsetup-generator.c
+++ b/src/cryptsetup/cryptsetup-generator.c
@@ -130,11 +130,26 @@ static int create_disk(
                     streq(password, "/dev/random") ||
                     streq(password, "/dev/hw_random"))
                         fputs("After=systemd-random-seed.service\n", f);
-                else if (!streq(password, "-") &&
-                         !streq(password, "none"))
-                        fprintf(f,
-                                "RequiresMountsFor=%s\n",
-                                password);
+                else {
+                        _cleanup_free_ char *uu = fstab_node_to_udev_node(password);
+                        if (uu == NULL)
+                                return log_oom();
+
+                        if (is_device_path(uu)) {
+                                _cleanup_free_ char *dd = unit_name_from_path(uu, ".device");
+                                if (dd == NULL)
+                                        return log_oom();
+
+                                fprintf(f,
+                                                "After=%s\n"
+                                                "Requires=%s\n",
+                                                dd, dd);
+                        } else if (!streq(password, "-") &&
+                                         !streq(password, "none"))
+                                        fprintf(f,
+                                                "RequiresMountsFor=%s\n",
+                                                password);
+                }
         }
 
         if (is_device_path(u))
-- 
1.8.5.4