From af4e8e86ec91389a04df2b1b8621c0ad5c84917b Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 5 Jun 2023 11:49:35 +0200
Subject: [PATCH 1/4] battery-util: split out code that checks AC power state
 into its own .c/.h pair

No code change, just some splitting out of the relevant code from
udev-util.[ch].

This makes sense on its own, but is also prepartion to move the code
that checks for low battery state into battery-util.[ch], too.
---
 src/ac-power/ac-power.c   |   2 +-
 src/login/logind-core.c   |   1 +
 src/shared/battery-util.c | 178 ++++++++++++++++++++++++++++++++++++++
 src/shared/battery-util.h |   4 +
 src/shared/condition.c    |   2 +-
 src/shared/meson.build    |   1 +
 src/shared/sleep-config.c |   4 +-
 src/shared/udev-util.c    | 170 ------------------------------------
 src/shared/udev-util.h    |   2 -
 src/test/test-condition.c |   2 +-
 10 files changed, 189 insertions(+), 177 deletions(-)
 create mode 100644 src/shared/battery-util.c
 create mode 100644 src/shared/battery-util.h

diff --git a/src/ac-power/ac-power.c b/src/ac-power/ac-power.c
index 853635047d..62181a83df 100644
--- a/src/ac-power/ac-power.c
+++ b/src/ac-power/ac-power.c
@@ -2,9 +2,9 @@
 
 #include <getopt.h>
 
+#include "battery-util.h"
 #include "build.h"
 #include "main-func.h"
-#include "udev-util.h"
 
 static bool arg_verbose = false;
 
diff --git a/src/login/logind-core.c b/src/login/logind-core.c
index dd4b246893..df67e5509b 100644
--- a/src/login/logind-core.c
+++ b/src/login/logind-core.c
@@ -8,6 +8,7 @@
 #include "sd-device.h"
 
 #include "alloc-util.h"
+#include "battery-util.h"
 #include "bus-error.h"
 #include "bus-locator.h"
 #include "bus-util.h"
diff --git a/src/shared/battery-util.c b/src/shared/battery-util.c
new file mode 100644
index 0000000000..aa93b531a0
--- /dev/null
+++ b/src/shared/battery-util.c
@@ -0,0 +1,178 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-device.h"
+
+#include "device-private.h"
+#include "device-util.h"
+#include "string-util.h"
+#include "battery-util.h"
+
+static int device_is_power_sink(sd_device *device) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        bool found_source = false, found_sink = false;
+        sd_device *parent, *d;
+        int r;
+
+        assert(device);
+
+        /* USB-C power supply device has two power roles: source or sink. See,
+         * https://docs.kernel.org/admin-guide/abi-testing.html#abi-file-testing-sysfs-class-typec */
+
+        r = sd_device_enumerator_new(&e);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_allow_uninitialized(e);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_add_match_subsystem(e, "typec", true);
+        if (r < 0)
+                return r;
+
+        r = sd_device_get_parent(device, &parent);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_add_match_parent(e, parent);
+        if (r < 0)
+                return r;
+
+        FOREACH_DEVICE(e, d) {
+                const char *val;
+
+                r = sd_device_get_sysattr_value(d, "power_role", &val);
+                if (r < 0) {
+                        if (r != -ENOENT)
+                                log_device_debug_errno(d, r, "Failed to read 'power_role' sysfs attribute, ignoring: %m");
+                        continue;
+                }
+
+                if (strstr(val, "[source]")) {
+                        found_source = true;
+                        log_device_debug(d, "The USB type-C port is in power source mode.");
+                } else if (strstr(val, "[sink]")) {
+                        found_sink = true;
+                        log_device_debug(d, "The USB type-C port is in power sink mode.");
+                }
+        }
+
+        if (found_sink)
+                log_device_debug(device, "The USB type-C device has at least one port in power sink mode.");
+        else if (!found_source)
+                log_device_debug(device, "The USB type-C device has no port in power source mode, assuming the device is in power sink mode.");
+        else
+                log_device_debug(device, "All USB type-C ports are in power source mode.");
+
+        return found_sink || !found_source;
+}
+
+static bool battery_is_discharging(sd_device *d) {
+        const char *val;
+        int r;
+
+        assert(d);
+
+        r = sd_device_get_sysattr_value(d, "scope", &val);
+        if (r < 0) {
+                if (r != -ENOENT)
+                        log_device_debug_errno(d, r, "Failed to read 'scope' sysfs attribute, ignoring: %m");
+        } else if (streq(val, "Device")) {
+                log_device_debug(d, "The power supply is a device battery, ignoring device.");
+                return false;
+        }
+
+        r = device_get_sysattr_bool(d, "present");
+        if (r < 0)
+                log_device_debug_errno(d, r, "Failed to read 'present' sysfs attribute, assuming the battery is present: %m");
+        else if (r == 0) {
+                log_device_debug(d, "The battery is not present, ignoring the power supply.");
+                return false;
+        }
+
+        /* Possible values: "Unknown", "Charging", "Discharging", "Not charging", "Full" */
+        r = sd_device_get_sysattr_value(d, "status", &val);
+        if (r < 0) {
+                log_device_debug_errno(d, r, "Failed to read 'status' sysfs attribute, assuming the battery is discharging: %m");
+                return true;
+        }
+        if (!streq(val, "Discharging")) {
+                log_device_debug(d, "The battery status is '%s', assuming the battery is not used as a power source of this machine.", val);
+                return false;
+        }
+
+        return true;
+}
+
+int on_ac_power(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        bool found_ac_online = false, found_discharging_battery = false;
+        sd_device *d;
+        int r;
+
+        r = sd_device_enumerator_new(&e);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_allow_uninitialized(e);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_add_match_subsystem(e, "power_supply", true);
+        if (r < 0)
+                return r;
+
+        FOREACH_DEVICE(e, d) {
+                /* See
+                 * https://github.com/torvalds/linux/blob/4eef766b7d4d88f0b984781bc1bcb574a6eafdc7/include/linux/power_supply.h#L176
+                 * for defined power source types. Also see:
+                 * https://docs.kernel.org/admin-guide/abi-testing.html#abi-file-testing-sysfs-class-power */
+
+                const char *val;
+                r = sd_device_get_sysattr_value(d, "type", &val);
+                if (r < 0) {
+                        log_device_debug_errno(d, r, "Failed to read 'type' sysfs attribute, ignoring device: %m");
+                        continue;
+                }
+
+                /* Ignore USB-C power supply in source mode. See issue #21988. */
+                if (streq(val, "USB")) {
+                        r = device_is_power_sink(d);
+                        if (r <= 0) {
+                                if (r < 0)
+                                        log_device_debug_errno(d, r, "Failed to determine the current power role, ignoring device: %m");
+                                else
+                                        log_device_debug(d, "USB power supply is in source mode, ignoring device.");
+                                continue;
+                        }
+                }
+
+                if (streq(val, "Battery")) {
+                        if (battery_is_discharging(d)) {
+                                found_discharging_battery = true;
+                                log_device_debug(d, "The power supply is a battery and currently discharging.");
+                        }
+                        continue;
+                }
+
+                r = device_get_sysattr_unsigned(d, "online", NULL);
+                if (r < 0) {
+                        log_device_debug_errno(d, r, "Failed to query 'online' sysfs attribute, ignoring device: %m");
+                        continue;
+                } else if (r > 0)  /* At least 1 and 2 are defined as different types of 'online' */
+                        found_ac_online = true;
+
+                log_device_debug(d, "The power supply is currently %s.", r > 0 ? "online" : "offline");
+        }
+
+        if (found_ac_online) {
+                log_debug("Found at least one online non-battery power supply, system is running on AC.");
+                return true;
+        } else if (found_discharging_battery) {
+                log_debug("Found at least one discharging battery and no online power sources, assuming system is running from battery.");
+                return false;
+        } else {
+                log_debug("No power supply reported online and no discharging battery found, assuming system is running on AC.");
+                return true;
+        }
+}
diff --git a/src/shared/battery-util.h b/src/shared/battery-util.h
new file mode 100644
index 0000000000..4089fff0c4
--- /dev/null
+++ b/src/shared/battery-util.h
@@ -0,0 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+int on_ac_power(void);
diff --git a/src/shared/condition.c b/src/shared/condition.c
index fce3fc2afb..9eb49d0eb5 100644
--- a/src/shared/condition.c
+++ b/src/shared/condition.c
@@ -18,6 +18,7 @@
 #include "apparmor-util.h"
 #include "architecture.h"
 #include "audit-util.h"
+#include "battery-util.h"
 #include "blockdev-util.h"
 #include "cap-list.h"
 #include "cgroup-util.h"
@@ -56,7 +57,6 @@
 #include "string-util.h"
 #include "tomoyo-util.h"
 #include "tpm2-util.h"
-#include "udev-util.h"
 #include "uid-alloc-range.h"
 #include "user-util.h"
 #include "virt.h"
diff --git a/src/shared/meson.build b/src/shared/meson.build
index 31241bc08d..b34d218c1e 100644
--- a/src/shared/meson.build
+++ b/src/shared/meson.build
@@ -6,6 +6,7 @@ shared_sources = files(
         'ask-password-api.c',
         'barrier.c',
         'base-filesystem.c',
+        'battery-util.c',
         'binfmt-util.c',
         'bitmap.c',
         'blockdev-util.c',
diff --git a/src/shared/sleep-config.c b/src/shared/sleep-config.c
index d388c89192..51aebf2f0d 100644
--- a/src/shared/sleep-config.c
+++ b/src/shared/sleep-config.c
@@ -18,6 +18,7 @@
 #include "sd-device.h"
 
 #include "alloc-util.h"
+#include "battery-util.h"
 #include "blockdev-util.h"
 #include "btrfs-util.h"
 #include "conf-parser.h"
@@ -34,15 +35,14 @@
 #include "log.h"
 #include "macro.h"
 #include "path-util.h"
-#include "sleep-config.h"
 #include "siphash24.h"
+#include "sleep-config.h"
 #include "stat-util.h"
 #include "stdio-util.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "strv.h"
 #include "time-util.h"
-#include "udev-util.h"
 
 #define BATTERY_LOW_CAPACITY_LEVEL 5
 #define DISCHARGE_RATE_FILEPATH "/var/lib/systemd/sleep/battery_discharge_percentage_rate_per_hour"
diff --git a/src/shared/udev-util.c b/src/shared/udev-util.c
index 646eaf9135..088eb0fe9a 100644
--- a/src/shared/udev-util.c
+++ b/src/shared/udev-util.c
@@ -591,176 +591,6 @@ int udev_queue_init(void) {
         return TAKE_FD(fd);
 }
 
-static int device_is_power_sink(sd_device *device) {
-        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
-        bool found_source = false, found_sink = false;
-        sd_device *parent, *d;
-        int r;
-
-        assert(device);
-
-        /* USB-C power supply device has two power roles: source or sink. See,
-         * https://docs.kernel.org/admin-guide/abi-testing.html#abi-file-testing-sysfs-class-typec */
-
-        r = sd_device_enumerator_new(&e);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_allow_uninitialized(e);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_add_match_subsystem(e, "typec", true);
-        if (r < 0)
-                return r;
-
-        r = sd_device_get_parent(device, &parent);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_add_match_parent(e, parent);
-        if (r < 0)
-                return r;
-
-        FOREACH_DEVICE(e, d) {
-                const char *val;
-
-                r = sd_device_get_sysattr_value(d, "power_role", &val);
-                if (r < 0) {
-                        if (r != -ENOENT)
-                                log_device_debug_errno(d, r, "Failed to read 'power_role' sysfs attribute, ignoring: %m");
-                        continue;
-                }
-
-                if (strstr(val, "[source]")) {
-                        found_source = true;
-                        log_device_debug(d, "The USB type-C port is in power source mode.");
-                } else if (strstr(val, "[sink]")) {
-                        found_sink = true;
-                        log_device_debug(d, "The USB type-C port is in power sink mode.");
-                }
-        }
-
-        if (found_sink)
-                log_device_debug(device, "The USB type-C device has at least one port in power sink mode.");
-        else if (!found_source)
-                log_device_debug(device, "The USB type-C device has no port in power source mode, assuming the device is in power sink mode.");
-        else
-                log_device_debug(device, "All USB type-C ports are in power source mode.");
-
-        return found_sink || !found_source;
-}
-
-static bool battery_is_discharging(sd_device *d) {
-        const char *val;
-        int r;
-
-        assert(d);
-
-        r = sd_device_get_sysattr_value(d, "scope", &val);
-        if (r < 0) {
-                if (r != -ENOENT)
-                        log_device_debug_errno(d, r, "Failed to read 'scope' sysfs attribute, ignoring: %m");
-        } else if (streq(val, "Device")) {
-                log_device_debug(d, "The power supply is a device battery, ignoring device.");
-                return false;
-        }
-
-        r = device_get_sysattr_bool(d, "present");
-        if (r < 0)
-                log_device_debug_errno(d, r, "Failed to read 'present' sysfs attribute, assuming the battery is present: %m");
-        else if (r == 0) {
-                log_device_debug(d, "The battery is not present, ignoring the power supply.");
-                return false;
-        }
-
-        /* Possible values: "Unknown", "Charging", "Discharging", "Not charging", "Full" */
-        r = sd_device_get_sysattr_value(d, "status", &val);
-        if (r < 0) {
-                log_device_debug_errno(d, r, "Failed to read 'status' sysfs attribute, assuming the battery is discharging: %m");
-                return true;
-        }
-        if (!streq(val, "Discharging")) {
-                log_device_debug(d, "The battery status is '%s', assuming the battery is not used as a power source of this machine.", val);
-                return false;
-        }
-
-        return true;
-}
-
-int on_ac_power(void) {
-        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
-        bool found_ac_online = false, found_discharging_battery = false;
-        sd_device *d;
-        int r;
-
-        r = sd_device_enumerator_new(&e);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_allow_uninitialized(e);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_add_match_subsystem(e, "power_supply", true);
-        if (r < 0)
-                return r;
-
-        FOREACH_DEVICE(e, d) {
-                /* See
-                 * https://github.com/torvalds/linux/blob/4eef766b7d4d88f0b984781bc1bcb574a6eafdc7/include/linux/power_supply.h#L176
-                 * for defined power source types. Also see:
-                 * https://docs.kernel.org/admin-guide/abi-testing.html#abi-file-testing-sysfs-class-power */
-
-                const char *val;
-                r = sd_device_get_sysattr_value(d, "type", &val);
-                if (r < 0) {
-                        log_device_debug_errno(d, r, "Failed to read 'type' sysfs attribute, ignoring device: %m");
-                        continue;
-                }
-
-                /* Ignore USB-C power supply in source mode. See issue #21988. */
-                if (streq(val, "USB")) {
-                        r = device_is_power_sink(d);
-                        if (r <= 0) {
-                                if (r < 0)
-                                        log_device_debug_errno(d, r, "Failed to determine the current power role, ignoring device: %m");
-                                else
-                                        log_device_debug(d, "USB power supply is in source mode, ignoring device.");
-                                continue;
-                        }
-                }
-
-                if (streq(val, "Battery")) {
-                        if (battery_is_discharging(d)) {
-                                found_discharging_battery = true;
-                                log_device_debug(d, "The power supply is a battery and currently discharging.");
-                        }
-                        continue;
-                }
-
-                r = device_get_sysattr_unsigned(d, "online", NULL);
-                if (r < 0) {
-                        log_device_debug_errno(d, r, "Failed to query 'online' sysfs attribute, ignoring device: %m");
-                        continue;
-                } else if (r > 0)  /* At least 1 and 2 are defined as different types of 'online' */
-                        found_ac_online = true;
-
-                log_device_debug(d, "The power supply is currently %s.", r > 0 ? "online" : "offline");
-        }
-
-        if (found_ac_online) {
-                log_debug("Found at least one online non-battery power supply, system is running on AC.");
-                return true;
-        } else if (found_discharging_battery) {
-                log_debug("Found at least one discharging battery and no online power sources, assuming system is running from battery.");
-                return false;
-        } else {
-                log_debug("No power supply reported online and no discharging battery found, assuming system is running on AC.");
-                return true;
-        }
-}
-
 bool udev_available(void) {
         static int cache = -1;
 
diff --git a/src/shared/udev-util.h b/src/shared/udev-util.h
index c3c3dbe842..175fa0b6f0 100644
--- a/src/shared/udev-util.h
+++ b/src/shared/udev-util.h
@@ -55,8 +55,6 @@ bool devpath_conflict(const char *a, const char *b);
 int udev_queue_is_empty(void);
 int udev_queue_init(void);
 
-int on_ac_power(void);
-
 bool udev_available(void);
 
 #if HAVE_SYS_SDT_H
diff --git a/src/test/test-condition.c b/src/test/test-condition.c
index 8f52dab8ce..317a104f4e 100644
--- a/src/test/test-condition.c
+++ b/src/test/test-condition.c
@@ -11,6 +11,7 @@
 #include "apparmor-util.h"
 #include "architecture.h"
 #include "audit-util.h"
+#include "battery-util.h"
 #include "cgroup-util.h"
 #include "condition.h"
 #include "cpu-set-util.h"
@@ -39,7 +40,6 @@
 #include "tests.h"
 #include "tmpfile-util.h"
 #include "tomoyo-util.h"
-#include "udev-util.h"
 #include "uid-alloc-range.h"
 #include "user-util.h"
 #include "virt.h"

From 319c46483e3eb1a3c33a3ca97b90ba13c3987da1 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 5 Jun 2023 11:56:31 +0200
Subject: [PATCH 2/4] battery-util: move battery_is_discharging_and_low() to
 battery-util.[ch]

This moves a first batch of functions from sleep-config.[ch] over to
battery-util.[ch].

In the long run we should probably move even more stuff over, i.e.
anything that deals with the battery sysfs driver interface.

No code change.
---
 src/shared/battery-util.c | 80 ++++++++++++++++++++++++++++++++++++++
 src/shared/battery-util.h |  7 ++++
 src/shared/sleep-config.c | 81 +--------------------------------------
 src/shared/sleep-config.h |  1 -
 src/sleep/sleep.c         |  1 +
 5 files changed, 89 insertions(+), 81 deletions(-)

diff --git a/src/shared/battery-util.c b/src/shared/battery-util.c
index aa93b531a0..b11b6dc989 100644
--- a/src/shared/battery-util.c
+++ b/src/shared/battery-util.c
@@ -7,6 +7,8 @@
 #include "string-util.h"
 #include "battery-util.h"
 
+#define BATTERY_LOW_CAPACITY_LEVEL 5
+
 static int device_is_power_sink(sd_device *device) {
         _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
         bool found_source = false, found_sink = false;
@@ -176,3 +178,81 @@ int on_ac_power(void) {
                 return true;
         }
 }
+
+/* Get the list of batteries */
+int battery_enumerator_new(sd_device_enumerator **ret) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        int r;
+
+        assert(ret);
+
+        r = sd_device_enumerator_new(&e);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_add_match_subsystem(e, "power_supply", /* match = */ true);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_allow_uninitialized(e);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_add_match_sysattr(e, "type", "Battery", /* match = */ true);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_add_match_sysattr(e, "present", "1", /* match = */ true);
+        if (r < 0)
+                return r;
+
+        r = sd_device_enumerator_add_match_sysattr(e, "scope", "Device", /* match = */ false);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(e);
+        return 0;
+}
+
+/* Battery percentage capacity fetched from capacity file and if in range 0-100 then returned */
+int battery_read_capacity_percentage(sd_device *dev) {
+        int battery_capacity, r;
+
+        assert(dev);
+
+        r = device_get_sysattr_int(dev, "capacity", &battery_capacity);
+        if (r < 0)
+                return log_device_debug_errno(dev, r, "Failed to read/parse POWER_SUPPLY_CAPACITY: %m");
+
+        if (battery_capacity < 0 || battery_capacity > 100)
+                return log_device_debug_errno(dev, SYNTHETIC_ERRNO(ERANGE), "Invalid battery capacity");
+
+        return battery_capacity;
+}
+
+/* If a battery whose percentage capacity is <= 5% exists, and we're not on AC power, return success */
+int battery_is_discharging_and_low(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        sd_device *dev;
+        int r;
+
+         /* We have not used battery capacity_level since value is set to full
+         * or Normal in case ACPI is not working properly. In case of no battery
+         * 0 will be returned and system will be suspended for 1st cycle then hibernated */
+
+        r = on_ac_power();
+        if (r < 0)
+                log_debug_errno(r, "Failed to check if the system is running on AC, assuming it is not: %m");
+        if (r > 0)
+                return false;
+
+        r = battery_enumerator_new(&e);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to initialize battery enumerator: %m");
+
+        FOREACH_DEVICE(e, dev)
+                if (battery_read_capacity_percentage(dev) > BATTERY_LOW_CAPACITY_LEVEL)
+                        return false;
+
+        return true;
+}
diff --git a/src/shared/battery-util.h b/src/shared/battery-util.h
index 4089fff0c4..c58f30b0b1 100644
--- a/src/shared/battery-util.h
+++ b/src/shared/battery-util.h
@@ -1,4 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include "sd-device.h"
+
 int on_ac_power(void);
+
+int battery_is_discharging_and_low(void);
+
+int battery_enumerator_new(sd_device_enumerator **ret);
+int battery_read_capacity_percentage(sd_device *dev);
diff --git a/src/shared/sleep-config.c b/src/shared/sleep-config.c
index 51aebf2f0d..4fd129b27e 100644
--- a/src/shared/sleep-config.c
+++ b/src/shared/sleep-config.c
@@ -44,7 +44,6 @@
 #include "strv.h"
 #include "time-util.h"
 
-#define BATTERY_LOW_CAPACITY_LEVEL 5
 #define DISCHARGE_RATE_FILEPATH "/var/lib/systemd/sleep/battery_discharge_percentage_rate_per_hour"
 #define BATTERY_DISCHARGE_RATE_HASH_KEY SD_ID128_MAKE(5f,9a,20,18,38,76,46,07,8d,36,58,0b,bb,c4,e0,63)
 #define SYS_ENTRY_RAW_FILE_TYPE1 "/sys/firmware/dmi/entries/1-0/raw"
@@ -128,41 +127,6 @@ int parse_sleep_config(SleepConfig **ret_sleep_config) {
         return 0;
 }
 
-/* Get the list of batteries */
-static int battery_enumerator_new(sd_device_enumerator **ret) {
-        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
-        int r;
-
-        assert(ret);
-
-        r = sd_device_enumerator_new(&e);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_add_match_subsystem(e, "power_supply", /* match = */ true);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_allow_uninitialized(e);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_add_match_sysattr(e, "type", "Battery", /* match = */ true);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_add_match_sysattr(e, "present", "1", /* match = */ true);
-        if (r < 0)
-                return r;
-
-        r = sd_device_enumerator_add_match_sysattr(e, "scope", "Device", /* match = */ false);
-        if (r < 0)
-                return r;
-
-        *ret = TAKE_PTR(e);
-        return 0;
-}
-
 int get_capacity_by_name(Hashmap *capacities_by_name, const char *name) {
         void *p;
 
@@ -176,49 +140,6 @@ int get_capacity_by_name(Hashmap *capacities_by_name, const char *name) {
         return PTR_TO_CAPACITY(p);
 }
 
-/* Battery percentage capacity fetched from capacity file and if in range 0-100 then returned */
-static int read_battery_capacity_percentage(sd_device *dev) {
-        int battery_capacity, r;
-
-        assert(dev);
-
-        r = device_get_sysattr_int(dev, "capacity", &battery_capacity);
-        if (r < 0)
-                return log_device_debug_errno(dev, r, "Failed to read/parse POWER_SUPPLY_CAPACITY: %m");
-
-        if (battery_capacity < 0 || battery_capacity > 100)
-                return log_device_debug_errno(dev, SYNTHETIC_ERRNO(ERANGE), "Invalid battery capacity");
-
-        return battery_capacity;
-}
-
-/* If a battery whose percentage capacity is <= 5% exists, and we're not on AC power, return success */
-int battery_is_discharging_and_low(void) {
-        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
-        sd_device *dev;
-        int r;
-
-         /* We have not used battery capacity_level since value is set to full
-         * or Normal in case ACPI is not working properly. In case of no battery
-         * 0 will be returned and system will be suspended for 1st cycle then hibernated */
-
-        r = on_ac_power();
-        if (r < 0)
-                log_debug_errno(r, "Failed to check if the system is running on AC, assuming it is not: %m");
-        if (r > 0)
-                return false;
-
-        r = battery_enumerator_new(&e);
-        if (r < 0)
-                return log_debug_errno(r, "Failed to initialize battery enumerator: %m");
-
-        FOREACH_DEVICE(e, dev)
-                if (read_battery_capacity_percentage(dev) > BATTERY_LOW_CAPACITY_LEVEL)
-                        return false;
-
-        return true;
-}
-
 /* Store current capacity of each battery before suspension and timestamp */
 int fetch_batteries_capacity_by_name(Hashmap **ret) {
         _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
@@ -241,7 +162,7 @@ int fetch_batteries_capacity_by_name(Hashmap **ret) {
                 const char *battery_name;
                 int battery_capacity;
 
-                battery_capacity = r = read_battery_capacity_percentage(dev);
+                battery_capacity = r = battery_read_capacity_percentage(dev);
                 if (r < 0)
                         continue;
 
diff --git a/src/shared/sleep-config.h b/src/shared/sleep-config.h
index 5c528b890b..b8245b129f 100644
--- a/src/shared/sleep-config.h
+++ b/src/shared/sleep-config.h
@@ -60,7 +60,6 @@ int find_hibernate_location(HibernateLocation **ret_hibernate_location);
 int can_sleep(SleepOperation operation);
 int can_sleep_disk(char **types);
 int can_sleep_state(char **types);
-int battery_is_discharging_and_low(void);
 int get_total_suspend_interval(Hashmap *last_capacity, usec_t *ret);
 int fetch_batteries_capacity_by_name(Hashmap **ret_current_capacity);
 int get_capacity_by_name(Hashmap *capacities_by_name, const char *name);
diff --git a/src/sleep/sleep.c b/src/sleep/sleep.c
index a9445c1a61..0dc3ad3558 100644
--- a/src/sleep/sleep.c
+++ b/src/sleep/sleep.c
@@ -17,6 +17,7 @@
 #include "sd-bus.h"
 #include "sd-messages.h"
 
+#include "battery-util.h"
 #include "btrfs-util.h"
 #include "build.h"
 #include "bus-error.h"

From c41e3605ec2f5c1d3040aa3a5fd57b9aee08c198 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 5 Jun 2023 12:12:03 +0200
Subject: [PATCH 3/4] battery-util: be more careful when determining whether we
 are in a low battery state

Let's avoid assuming a low battery battery state if in doubt. That
means, handle errors reading battery state gracefully.
---
 src/shared/battery-util.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/shared/battery-util.c b/src/shared/battery-util.c
index b11b6dc989..948a5e3b9d 100644
--- a/src/shared/battery-util.c
+++ b/src/shared/battery-util.c
@@ -233,6 +233,7 @@ int battery_read_capacity_percentage(sd_device *dev) {
 /* If a battery whose percentage capacity is <= 5% exists, and we're not on AC power, return success */
 int battery_is_discharging_and_low(void) {
         _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        bool unsure = false, found_low = false;
         sd_device *dev;
         int r;
 
@@ -250,9 +251,29 @@ int battery_is_discharging_and_low(void) {
         if (r < 0)
                 return log_debug_errno(r, "Failed to initialize battery enumerator: %m");
 
-        FOREACH_DEVICE(e, dev)
-                if (battery_read_capacity_percentage(dev) > BATTERY_LOW_CAPACITY_LEVEL)
+        FOREACH_DEVICE(e, dev) {
+                int level;
+
+                level = battery_read_capacity_percentage(dev);
+                if (level < 0) {
+                        unsure = true;
+                        continue;
+                }
+
+                if (level > BATTERY_LOW_CAPACITY_LEVEL) /* Found a charged battery */
                         return false;
 
-        return true;
+                found_low = true;
+        }
+
+        /* If we found a battery whose state we couldn't read, don't assume we are in low battery state */
+        if (unsure)
+                return false;
+
+        /* Found no charged battery, but did find low batteries */
+        if (found_low)
+                return true;
+
+        /* Found neither charged nor low batteries? let's return that we aren't on low battery state */
+        return false;
 }

From 7f1520c6a150f4eea531ef6e57d5bd37c682af21 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 5 Jun 2023 12:14:12 +0200
Subject: [PATCH 4/4] ac-power: add --low switch to systemd-ac-power tool

This allows checking from shell scripts whether the system is in a low
battery state. It just exposed the code we anyway have in a directly
accessible way.

This is also very useful for testing things.
---
 man/systemd-ac-power.xml |  8 ++++++++
 src/ac-power/ac-power.c  | 26 ++++++++++++++++++++++----
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/man/systemd-ac-power.xml b/man/systemd-ac-power.xml
index a4c9378cfd..e06a88a975 100644
--- a/man/systemd-ac-power.xml
+++ b/man/systemd-ac-power.xml
@@ -50,6 +50,14 @@
         <listitem><para>Show result as text instead of just returning success or failure.</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><option>--low</option></term>
+
+        <listitem><para>Instead of showing AC power state, show low battery state. In this case will return
+        zero if all batteries are currently discharging and below 5% of maximum charge. Returns non-zero
+        otherwise.</para></listitem>
+      </varlistentry>
+
       <xi:include href="standard-options.xml" xpointer="help" />
       <xi:include href="standard-options.xml" xpointer="version" />
     </variablelist>
diff --git a/src/ac-power/ac-power.c b/src/ac-power/ac-power.c
index 62181a83df..f027c31208 100644
--- a/src/ac-power/ac-power.c
+++ b/src/ac-power/ac-power.c
@@ -8,12 +8,18 @@
 
 static bool arg_verbose = false;
 
+static enum {
+        ACTION_AC_POWER,
+        ACTION_LOW,
+} arg_action = ACTION_AC_POWER;
+
 static void help(void) {
         printf("%s\n\n"
                "Report whether we are connected to an external power source.\n\n"
                "  -h --help             Show this help\n"
                "     --version          Show package version\n"
-               "  -v --verbose          Show state as text\n",
+               "  -v --verbose          Show state as text\n"
+               "     --low              Checks if battery is discharing and low\n",
                program_invocation_short_name);
 }
 
@@ -21,12 +27,14 @@ static int parse_argv(int argc, char *argv[]) {
 
         enum {
                 ARG_VERSION = 0x100,
+                ARG_LOW,
         };
 
         static const struct option options[] = {
                 { "help",    no_argument, NULL, 'h'         },
                 { "version", no_argument, NULL, ARG_VERSION },
                 { "verbose", no_argument, NULL, 'v'         },
+                { "low",     no_argument, NULL, ARG_LOW     },
                 {}
         };
 
@@ -50,6 +58,10 @@ static int parse_argv(int argc, char *argv[]) {
                         arg_verbose = true;
                         break;
 
+                case ARG_LOW:
+                        arg_action = ACTION_LOW;
+                        break;
+
                 case '?':
                         return -EINVAL;
 
@@ -78,9 +90,15 @@ static int run(int argc, char *argv[]) {
         if (r <= 0)
                 return r;
 
-        r = on_ac_power();
-        if (r < 0)
-                return log_error_errno(r, "Failed to read AC status: %m");
+        if (arg_action == ACTION_AC_POWER) {
+                r = on_ac_power();
+                if (r < 0)
+                        return log_error_errno(r, "Failed to read AC status: %m");
+        } else {
+                r = battery_is_discharging_and_low();
+                if (r < 0)
+                        return log_error_errno(r, "Failed to read battery discharging + low status: %m");
+        }
 
         if (arg_verbose)
                 puts(yes_no(r));