Merge pull request #22006 from yuwata/on-ac-power

udev-util: ignore USB-C ports in power source mode

src/ac-power/ac-power.c

@@ -3,7 +3,7 @@
 #include <getopt.h>
 
 #include "main-func.h"
-#include "util.h"
+#include "udev-util.h"
 
 static bool arg_verbose = false;
 

src/basic/util.c

@@ -6,7 +6,6 @@
 
 #include "alloc-util.h"
 #include "build.h"
-#include "dirent-util.h"
 #include "env-file.h"
 #include "env-util.h"
 #include "fd-util.h"
@@ -115,65 +114,6 @@ void in_initrd_force(bool value) {
         saved_in_initrd = value;
 }
 
-int on_ac_power(void) {
-        bool found_offline = false, found_online = false;
-        _cleanup_closedir_ DIR *d = NULL;
-        int r;
-
-        d = opendir("/sys/class/power_supply");
-        if (!d)
-                return errno == ENOENT ? true : -errno;
-
-        FOREACH_DIRENT(de, d, return -errno) {
-                _cleanup_close_ int device_fd = -1;
-                _cleanup_free_ char *contents = NULL;
-                unsigned v;
-
-                device_fd = openat(dirfd(d), de->d_name, O_DIRECTORY|O_RDONLY|O_CLOEXEC);
-                if (device_fd < 0) {
-                        if (IN_SET(errno, ENOENT, ENOTDIR))
-                                continue;
-
-                        return -errno;
-                }
-
-                r = read_virtual_file_at(device_fd, "type", SIZE_MAX, &contents, NULL);
-                if (r == -ENOENT)
-                        continue;
-                if (r < 0)
-                        return r;
-
-                delete_trailing_chars(contents, NEWLINE);
-
-                /* We assume every power source is AC, except for batteries. See
-                 * https://github.com/torvalds/linux/blob/4eef766b7d4d88f0b984781bc1bcb574a6eafdc7/include/linux/power_supply.h#L176
-                 * for defined power source types. Also see:
-                 * https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-power */
-                if (streq(contents, "Battery"))
-                        continue;
-
-                contents = mfree(contents);
-
-                r = read_virtual_file_at(device_fd, "online", SIZE_MAX, &contents, NULL);
-                if (r == -ENOENT)
-                        continue;
-                if (r < 0)
-                        return r;
-
-                delete_trailing_chars(contents, NEWLINE);
-
-                r = safe_atou(contents, &v);
-                if (r < 0)
-                        return r;
-                if (v > 0) /* At least 1 and 2 are defined as different types of 'online' */
-                        found_online = true;
-                else
-                        found_offline = true;
-        }
-
-        return found_online || !found_offline;
-}
-
 int container_get_leader(const char *machine, pid_t *pid) {
         _cleanup_free_ char *s = NULL, *class = NULL;
         const char *p;

src/basic/util.h

@@ -20,8 +20,6 @@ int prot_from_flags(int flags) _const_;
 bool in_initrd(void);
 void in_initrd_force(bool value);
 
-int on_ac_power(void);
-
 /* Note: log2(0) == log2(1) == 0 here and below. */
 
 #define CONST_LOG2ULL(x) ((x) > 1 ? (unsigned) __builtin_clzll(x) ^ 63U : 0)

src/shared/condition.c

@@ -50,9 +50,9 @@
 #include "string-table.h"
 #include "string-util.h"
 #include "tomoyo-util.h"
+#include "udev-util.h"
 #include "uid-alloc-range.h"
 #include "user-util.h"
-#include "util.h"
 #include "virt.h"
 
 Condition* condition_new(ConditionType type, const char *parameter, bool trigger, bool negate) {

src/shared/udev-util.c

@@ -579,3 +579,142 @@ 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://www.kernel.org/doc/Documentation/ABI/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;
+}
+
+int on_ac_power(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        bool found_offline = false, found_online = 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) {
+                const char *val;
+                unsigned v;
+
+                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: %m");
+                        continue;
+                }
+
+                /* We assume every power source is AC, except for batteries. See
+                 * https://github.com/torvalds/linux/blob/4eef766b7d4d88f0b984781bc1bcb574a6eafdc7/include/linux/power_supply.h#L176
+                 * for defined power source types. Also see:
+                 * https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-power */
+                if (streq(val, "Battery")) {
+                        log_device_debug(d, "The power supply is battery, ignoring.");
+                        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: %m");
+                                else
+                                        log_device_debug(d, "USB power supply is in source mode, ignoring.");
+                                continue;
+                        }
+                }
+
+                r = sd_device_get_sysattr_value(d, "online", &val);
+                if (r < 0) {
+                        log_device_debug_errno(d, r, "Failed to read 'online' sysfs attribute, ignoring: %m");
+                        continue;
+                }
+
+                r = safe_atou(val, &v);
+                if (r < 0) {
+                        log_device_debug_errno(d, r, "Failed to parse 'online' attribute, ignoring: %m");
+                        continue;
+                }
+
+                if (v > 0) /* At least 1 and 2 are defined as different types of 'online' */
+                        found_online = true;
+                else
+                        found_offline = true;
+
+                log_device_debug(d, "The power supply is currently %s.", v > 0 ? "online" : "offline");
+        }
+
+        if (found_online)
+                log_debug("Found at least one online non-battery power supply, system is running on AC power.");
+        else if (!found_offline)
+                log_debug("Found no offline non-battery power supply, assuming system is running on AC power.");
+        else
+                log_debug("All non-battery power supplies are offline, assuming system is running with battery.");
+
+        return found_online || !found_offline;
+}

src/shared/udev-util.h

@@ -53,6 +53,8 @@ int udev_resolve_subsys_kernel(const char *string, char *result, size_t maxsize,
 int udev_queue_is_empty(void);
 int udev_queue_init(void);
 
+int on_ac_power(void);
+
 #if HAVE_SYS_SDT_H
 
 /* Each trace point can have different number of additional arguments. Note that when the macro is used only

src/test/test-condition.c

@@ -33,6 +33,7 @@
 #include "strv.h"
 #include "tests.h"
 #include "tomoyo-util.h"
+#include "udev-util.h"
 #include "uid-alloc-range.h"
 #include "user-util.h"
 #include "virt.h"