morgan/systemd
1
0
Fork 0
mirror of https://github.com/morgan9e/systemd synced 2026-04-15 00:47:10 +09:00
Code Issues Packages Projects Releases Wiki Activity

util: invert ac_power() source type check

Browse Source 
So far we assumed every power source was a battery except for the ones
which definitely are not. I think this logic makes little sense, as
"battery" is kinda the exceptional case here, not the other way round.
Hence let's invert the type check, and denylist "Battery" devices rather
than allowlist "Mains" devices.

This should increase compatibility with alternative types of power
sources, in particular USB ones.

This takes into account that additional power types have been added
since we wrote the original code, and in particular should cover the
siutation discussed here OK:

https://sources.debian.org/src/powermgmt-base/1.36/power_supply.txt/#L31
https://sources.debian.org/src/powermgmt-base/1.36/on_ac_power/#L25

Also, modernizes the code in various was ways.

Inspired by and fixes: #20964
This commit is contained in:
Lennart Poettering
2021-10-11 10:54:31 +02:00
parent 6bfd44ee04
commit c19a51bec4
1 changed files with 29 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

63
src/basic/util.c
View File

@@ -119,62 +119,57 @@ int on_ac_power(void) {
bool found_offline = false, found_online = false;
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
int r;
d = opendir("/sys/class/power_supply");
if (!d)
return errno == ENOENT ? true : -errno;
FOREACH_DIRENT(de, d, return -errno) {
_cleanup_close_ int fd = -1, device = -1;
char contents[6];
ssize_t n;
_cleanup_close_ int device_fd = -1;
_cleanup_free_ char *contents = NULL;
unsigned v;
device = openat(dirfd(d), de->d_name, O_DIRECTORY|O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (device < 0) {
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;
}
fd = openat(device, "type", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0) {
if (errno == ENOENT)
continue;
r = read_virtual_file_at(device_fd, "type", SIZE_MAX, &contents, NULL);
if (r == -ENOENT)
continue;
if (r < 0)
return r;
return -errno;
}
delete_trailing_chars(contents, NEWLINE);
n = read(fd, contents, sizeof(contents));
if (n < 0)
return -errno;
if (n != 6 || memcmp(contents, "Mains\n", 6))
/* 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;
safe_close(fd);
fd = openat(device, "online", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0) {
if (errno == ENOENT)
continue;
contents = mfree(contents);
return -errno;
}
r = read_virtual_file_at(device_fd, "online", SIZE_MAX, &contents, NULL);
if (r == -ENOENT)
continue;
if (r < 0)
return r;
n = read(fd, contents, sizeof(contents));
if (n < 0)
return -errno;
delete_trailing_chars(contents, NEWLINE);
if (n != 2 || contents[1] != '\n')
return -EIO;
if (contents[0] == '1') {
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;
break;
} else if (contents[0] == '0')
found_offline = true;
else
return -EIO;
found_offline = true;
}
return found_online || !found_offline;