[systemd-devel] [PATCH] udev: Allow the 'udevadm settle' timeout to be set via the kernel cmdline

[Colin Guthrie]

On some really old hardware, the default timeout of 120 (which may even
be reduced further on the command line) is insufficient.

While such cases are specialist and (nowadays) relatively rare, it is
still nice to be able to provide a method to increase the timeout
when needed.

Bug Link: https://bugs.mageia.org/show_bug.cgi?id=3315
---

I posted this one a while back before udev merge IIRC and was asked to
make it use the newer APIs etc. which I've done. Can't remember if I
reposted it back to the list or not. Would be nice if it was upstream
just to save me carrying a fairly generic patch downstream.

It's quite a small patch, but there is no doc on this. Is there a file
into which I should put a small chunk of doc on this option?


 src/udev/udevadm-settle.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src/udev/udevadm-settle.c b/src/udev/udevadm-settle.c
index c4fc4ee..1871071 100644
--- a/src/udev/udevadm-settle.c
+++ b/src/udev/udevadm-settle.c
@@ -53,6 +53,7 @@ static int adm_settle(struct udev *udev, int argc, char *argv[])
         int quiet = 0;
         const char *exists = NULL;
         unsigned int timeout = 120;
+        char *line;
         struct pollfd pfd[1] = { {.fd = -1}, };
         struct udev_queue *udev_queue = NULL;
         int rc = EXIT_FAILURE;
@@ -99,6 +100,37 @@ static int adm_settle(struct udev *udev, int argc, char *argv[])
                 }
         }
 
+        /*
+         * read the kernel commandline, in case we need to tweak timeout
+         *   udev.settle-timeout=<timeout>  settle timeout
+         *
+         */
+        if (read_one_line_file("/proc/cmdline", &line) >= 0) {
+                char *w, *state;
+                size_t l;
+
+                FOREACH_WORD_QUOTED(w, l, line, state) {
+                        char *s, *opt;
+
+                        s = strndup(w, l);
+                        if (!s)
+                                break;
+
+                        /* accept the same options for the initrd, prefixed with "rd." */
+                        if (in_initrd() && startswith(s, "rd."))
+                                opt = s + 3;
+                        else
+                                opt = s;
+
+                        if (startswith(opt, "udev.settle-timeout=") && safe_atou(opt + 20, &timeout) >= 0)
+                                log_debug("timeout=%i (via kernel cmdline)\n", timeout);
+
+                        free(s);
+                }
+
+                free(line);
+        }
+
         udev_queue = udev_queue_new(udev);
         if (udev_queue == NULL)
                 exit(2);
-- 
1.8.1.2