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From e6682abae36dcfe8a093686a3bd67b3568157c35 Mon Sep 17 00:00:00 2001
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From: Peter Hutterer <peter.hutterer@who-t.net>
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Date: Thu, 19 Mar 2015 14:19:58 +1000
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Subject: [PATCH] udev: builtin-keyboard: add support for EVDEV_ABS_*
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Parse properties in the form
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EVDEV_ABS_00="<min>:<max>:<res>:<fuzz>:<flat>"
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and apply them to the kernel device. Future processes that open that device
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will see the updated EV_ABS range.
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This is particularly useful for touchpads that don't provide a resolution in
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the kernel driver but can be fixed up through hwdb entries (e.g. bcm5974).
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All values in the property are optional, e.g. a string of "::45" is valid to
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set the resolution to 45.
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The order intentionally orders resolution before fuzz and flat despite it
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being the last element in the absinfo struct. The use-case for setting
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fuzz/flat is almost non-existent, resolution is probably the most common case
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we'll need.
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To avoid multiple hwdb invocations for the same device, replace the
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hwdb "keyboard:" prefix with "evdev:" and drop the separate 60-keyboard.rules
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file. The new 60-evdev.rules is called for all event nodes
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anyway, we don't need a separate rules file and second callout to the hwdb
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builtin.
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(cherry picked from commit 51c0c2869845a058268d54c3111d55d0dd485704)
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Changes to the upstream commit:
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- 60-keyboard.rules is left in place, the 60-keyboard.hwdb is left
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  unmodified. This avoids any potential breakage from user-installed hwdb
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  files that are triggered by that rule.
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Conflicts:
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	hwdb/60-keyboard.hwdb
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	rules/60-keyboard.rules
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Resolves: #1500119
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---
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 Makefile.am                      |  2 +
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 hwdb/60-evdev.hwdb               | 37 ++++++++++++++
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 rules/60-evdev.rules             | 14 ++++++
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 src/udev/udev-builtin-keyboard.c | 86 ++++++++++++++++++++++++++++++--
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 4 files changed, 135 insertions(+), 4 deletions(-)
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 create mode 100644 hwdb/60-evdev.hwdb
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 create mode 100644 rules/60-evdev.rules
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diff --git a/Makefile.am b/Makefile.am
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index a1ebf5cb07..13c93f485e 100644
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--- a/Makefile.am
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+++ b/Makefile.am
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@@ -3499,6 +3499,7 @@ dist_udevrules_DATA += \
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 	rules/42-usb-hid-pm.rules \
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 	rules/50-udev-default.rules \
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 	rules/60-drm.rules \
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+	rules/60-evdev.rules \
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 	rules/60-keyboard.rules \
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 	rules/60-persistent-storage-tape.rules \
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 	rules/60-persistent-serial.rules \
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@@ -3702,6 +3703,7 @@ dist_udevhwdb_DATA = \
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 	hwdb/20-acpi-vendor.hwdb \
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 	hwdb/20-OUI.hwdb \
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 	hwdb/20-net-ifname.hwdb \
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+	hwdb/60-evdev.hwdb \
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 	hwdb/60-keyboard.hwdb \
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 	hwdb/70-mouse.hwdb \
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 	hwdb/70-touchpad.hwdb
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diff --git a/hwdb/60-evdev.hwdb b/hwdb/60-evdev.hwdb
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new file mode 100644
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index 0000000000..ad2d09e721
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--- /dev/null
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+++ b/hwdb/60-evdev.hwdb
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@@ -0,0 +1,37 @@
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+# This file is part of systemd.
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+#
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+# The lookup keys are composed in:
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+#   60-evdev.rules
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+#
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+# Note: The format of the "evdev:" prefix match key is a
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+# contract between the rules file and the hardware data, it might
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+# change in later revisions to support more or better matches, it
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+# is not necessarily expected to be a stable ABI.
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+#
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+# Match string formats:
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+# evdev:<modalias>
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+# evdev:name:<device name>:dmi:<dmi string>
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+#
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+# To add local entries, create a new file
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+#   /etc/udev/hwdb.d/61-evdev-local.hwdb
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+# and add your rules there. To load the new rules execute (as root):
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+#   udevadm hwdb --update
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+#   udevadm trigger /dev/input/eventXX
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+# where /dev/input/eventXX is the device in question. If in
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+# doubt, simply use /dev/input/event* to reload all input rules.
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+#
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+# If your changes are generally applicable, open a bug report on
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+#   http://bugs.freedesktop.org/enter_bug.cgi?product=systemd
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+# and include your new rules, a description of the device, and the
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+# output of
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+#   udevadm info /dev/input/eventXX
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+# (or /dev/input/event*).
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+#
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+# Allowed properties are:
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+#    EVDEV_ABS_<axis>=<min>:<max>:<res>:<fuzz>:<flat>
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+#
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+# where <axis> is the hexadecimal EV_ABS code as listed in linux/input.h
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+# and min, max, res, fuzz, flat are the decimal values to the respective
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+# fields of the struct input_absinfo as listed in linux/input.h.
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+# If a field is missing the field will be left as-is. Not all fields need to
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+# be present. e.g. ::45 sets the resolution to 45 units/mm.
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diff --git a/rules/60-evdev.rules b/rules/60-evdev.rules
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new file mode 100644
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index 0000000000..67308ad230
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--- /dev/null
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+++ b/rules/60-evdev.rules
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@@ -0,0 +1,14 @@
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+# do not edit this file, it will be overwritten on update
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+
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+ACTION=="remove", GOTO="evdev_end"
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+KERNEL!="event*", GOTO="evdev_end"
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+
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+# skip later rules when we find something for this input device
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+IMPORT{builtin}="hwdb --subsystem=input --lookup-prefix=evdev:", \
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+  RUN{builtin}+="keyboard", GOTO="evdev_end"
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+
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+# device matching the input device name and the machine's DMI data
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+KERNELS=="input*", IMPORT{builtin}="hwdb 'evdev:name:$attr{name}:$attr{[dmi/id]modalias}'", \
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+  RUN{builtin}+="keyboard", GOTO="evdev_end"
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+
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+LABEL="evdev_end"
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diff --git a/src/udev/udev-builtin-keyboard.c b/src/udev/udev-builtin-keyboard.c
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index 86f4018ef5..eaa21abf60 100644
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--- a/src/udev/udev-builtin-keyboard.c
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+++ b/src/udev/udev-builtin-keyboard.c
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@@ -99,6 +99,69 @@ static void map_keycode(int fd, const char *devnode, int scancode, const char *k
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                 log_error_errno(errno, "Error calling EVIOCSKEYCODE on device node '%s' (scan code 0x%x, key code %d): %m", devnode, map.scan, map.key);
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 }
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+static inline char* parse_token(const char *current, int32_t *val_out) {
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+        char *next;
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+        int32_t val;
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+
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+        if (!current)
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+                return NULL;
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+
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+        val = strtol(current, &next, 0);
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+        if (*next && *next != ':')
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+                return NULL;
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+
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+        if (next != current)
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+                *val_out = val;
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+
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+        if (*next)
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+                next++;
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+
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+        return next;
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+}
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+
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+static void override_abs(int fd, const char *devnode,
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+                         unsigned evcode, const char *value) {
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+        struct input_absinfo absinfo;
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+        int rc;
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+        char *next;
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+
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+        rc = ioctl(fd, EVIOCGABS(evcode), &absinfo);
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+        if (rc < 0) {
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+                log_error_errno(errno, "Error, unable to EVIOCGABS device '%s'",
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+                                devnode);
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+                return;
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+        }
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+
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+        next = parse_token(value, &absinfo.minimum);
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+        next = parse_token(next, &absinfo.maximum);
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+        next = parse_token(next, &absinfo.resolution);
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+        next = parse_token(next, &absinfo.fuzz);
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+        next = parse_token(next, &absinfo.flat);
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+        if (!next) {
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+                log_error("Error, unable to parse EV_ABS override '%s' for '%s'\n",
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+                          value, devnode);
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+                return;
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+        }
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+
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+        log_debug("keyboard: override %x with %d/%d/%d/%d/%d", evcode,
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+                  absinfo.minimum, absinfo.maximum, absinfo.resolution,
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+                  absinfo.fuzz, absinfo.flat);
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+        rc = ioctl(fd, EVIOCSABS(evcode), &absinfo);
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+        if (rc < 0)
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+                log_error_errno(errno, "Error, unable to update device '%s'",
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+                                devnode);
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+}
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+
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+static int open_device(const char *devnode) {
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+        int fd;
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+
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+        fd = open(devnode, O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
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+        if (fd < 0)
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+                log_error_errno(errno, "Error, opening device '%s': %m", devnode);
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+
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+        return fd < 0 ? -errno : fd;
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+}
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+
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 static int builtin_keyboard(struct udev_device *dev, int argc, char *argv[], bool test) {
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         struct udev_list_entry *entry;
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         unsigned release[1024];
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@@ -143,14 +206,29 @@ static int builtin_keyboard(struct udev_device *dev, int argc, char *argv[], boo
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                         }
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                         if (fd == -1) {
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-                                fd = open(node, O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
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-                                if (fd < 0) {
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-                                        log_error_errno(errno, "Error, opening device '%s': %m", node);
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+                                fd = open_device(node);
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+                                if (fd < 0)
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                                         return EXIT_FAILURE;
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-                                }
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                         }
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                         map_keycode(fd, node, scancode, keycode);
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+                } else if (startswith(key, "EVDEV_ABS_")) {
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+                        unsigned evcode;
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+
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+                        /* EVDEV_ABS_<EV_ABS code>=<min>:<max>:<res>:<fuzz>:<flat> */
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+                        evcode = strtoul(key + 10, &endptr, 16);
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+                        if (endptr[0] != '\0') {
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+                                log_error("Error, unable to parse EV_ABS code from '%s'", key);
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+                                continue;
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+                        }
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+
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+                        if (fd == -1) {
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+                                fd = open_device(node);
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+                                if (fd < 0)
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+                                        return EXIT_FAILURE;
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+                        }
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+
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+                        override_abs(fd, node, evcode, udev_list_entry_get_value(entry));
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                 }
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         }
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