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Merge pull request #17020 from yuwata/backlight 

backlight: validate sysattr value
This commit is contained in:
Lennart Poettering 2020-09-11 14:23:47 +02:00 committed by GitHub
parent 2ac4d1d45b 3bacb7e73b
commit f7c87baeca
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 102 additions and 51 deletions
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128
src/backlight/backlight.c
View File

@ -261,17 +261,13 @@ static int get_max_brightness(sd_device *device, unsigned *ret) {
* max_brightness in case of 'backlight' subsystem. This avoids preserving
* an unreadably dim screen, which would otherwise force the user to
* disable state restoration. */
static int clamp_brightness(sd_device *device, char **value, unsigned max_brightness) {
unsigned brightness, new_brightness, min_brightness;
static int clamp_brightness(sd_device *device, bool saved, unsigned max_brightness, unsigned *brightness) {
unsigned new_brightness, min_brightness;
const char *subsystem;
int r;
assert(value);
assert(*value);
r = safe_atou(*value, &brightness);
if (r < 0)
return log_device_warning_errno(device, r, "Failed to parse brightness \"%s\": %m", *value);
assert(device);
assert(brightness);
r = sd_device_get_subsystem(device, &subsystem);
if (r < 0)
@ -282,22 +278,16 @@ static int clamp_brightness(sd_device *device, char **value, unsigned max_bright
else
min_brightness = 0;
new_brightness = CLAMP(brightness, min_brightness, max_brightness);
if (new_brightness != brightness) {
char *new_value;
r = asprintf(&new_value, "%u", new_brightness);
if (r < 0)
return log_oom();
log_device_info(device, "Saved brightness %s %s to %s.", *value,
new_brightness > brightness ?
new_brightness = CLAMP(*brightness, min_brightness, max_brightness);
if (new_brightness != *brightness)
log_device_info(device, "%s brightness %u is %s to %u.",
saved ? "Saved" : "Current",
*brightness,
new_brightness > *brightness ?
"too low; increasing" : "too high; decreasing",
new_value);
free_and_replace(*value, new_value);
}
new_brightness);
*brightness = new_brightness;
return 0;
}
@ -309,7 +299,8 @@ static bool shall_clamp(sd_device *d) {
r = sd_device_get_property_value(d, "ID_BACKLIGHT_CLAMP", &s);
if (r < 0) {
log_device_debug_errno(d, r, "Failed to get ID_BACKLIGHT_CLAMP property, ignoring: %m");
if (r != -ENOENT)
log_device_debug_errno(d, r, "Failed to get ID_BACKLIGHT_CLAMP property, ignoring: %m");
return true;
}
@ -322,31 +313,60 @@ static bool shall_clamp(sd_device *d) {
return r;
}
static int read_brightness(sd_device *device, const char **ret) {
const char *subsystem;
static int read_brightness(sd_device *device, unsigned max_brightness, unsigned *ret_brightness) {
const char *subsystem, *value;
unsigned brightness;
int r;
assert(device);
assert(ret);
assert(ret_brightness);
r = sd_device_get_subsystem(device, &subsystem);
if (r < 0)
return log_device_debug_errno(device, r, "Failed to get subsystem: %m");
if (streq(subsystem, "backlight")) {
r = sd_device_get_sysattr_value(device, "actual_brightness", ret);
if (r >= 0)
return 0;
if (r != -ENOENT)
r = sd_device_get_sysattr_value(device, "actual_brightness", &value);
if (r == -ENOENT) {
log_device_debug_errno(device, r, "Failed to read 'actual_brightness' attribute, "
"fall back to use 'brightness' attribute: %m");
goto use_brightness;
}
if (r < 0)
return log_device_debug_errno(device, r, "Failed to read 'actual_brightness' attribute: %m");
log_device_debug_errno(device, r, "Failed to read 'actual_brightness' attribute, fall back to use 'brightness' attribute: %m");
r = safe_atou(value, &brightness);
if (r < 0) {
log_device_debug_errno(device, r, "Failed to parse 'actual_brightness' attribute, "
"fall back to use 'brightness' attribute: %s", value);
goto use_brightness;
}
if (brightness > max_brightness) {
log_device_debug(device, "actual_brightness=%u is larger than max_brightness=%u, "
"fall back to use 'brightness' attribute", brightness, max_brightness);
goto use_brightness;
}
*ret_brightness = brightness;
return 0;
}
r = sd_device_get_sysattr_value(device, "brightness", ret);
use_brightness:
r = sd_device_get_sysattr_value(device, "brightness", &value);
if (r < 0)
return log_device_debug_errno(device, r, "Failed to read 'brightness' attribute: %m");
r = safe_atou(value, &brightness);
if (r < 0)
return log_device_debug_errno(device, r, "Failed to parse 'brightness' attribute: %s", value);
if (brightness > max_brightness)
return log_device_debug_errno(device, SYNTHETIC_ERRNO(EINVAL),
"brightness=%u is larger than max_brightness=%u",
brightness, max_brightness);
*ret_brightness = brightness;
return 0;
}
@ -354,7 +374,7 @@ static int run(int argc, char *argv[]) {
_cleanup_(sd_device_unrefp) sd_device *device = NULL;
_cleanup_free_ char *escaped_ss = NULL, *escaped_sysname = NULL, *escaped_path_id = NULL;
const char *sysname, *path_id, *ss, *saved;
unsigned max_brightness;
unsigned max_brightness, brightness;
int r;
log_setup_service();
@ -431,44 +451,50 @@ static int run(int argc, char *argv[]) {
clamp = shall_clamp(device);
r = read_one_line_file(saved, &value);
if (IN_SET(r, -ENOENT, 0)) {
const char *curval;
if (r < 0 && r != -ENOENT)
return log_error_errno(r, "Failed to read %s: %m", saved);
if (r > 0) {
r = safe_atou(value, &brightness);
if (r < 0) {
log_error_errno(r, "Failed to parse saved brightness '%s', removing %s.",
value, saved);
(void) unlink(saved);
} else {
if (clamp)
(void) clamp_brightness(device, true, max_brightness, &brightness);
/* Fallback to clamping current brightness or exit early if
* clamping is not supported/enabled. */
/* Do not fall back to read current brightness below. */
r = 1;
}
}
if (r <= 0) {
/* Fallback to clamping current brightness or exit early if clamping is not
* supported/enabled. */
if (!clamp)
return 0;
r = read_brightness(device, &curval);
r = read_brightness(device, max_brightness, &brightness);
if (r < 0)
return log_device_error_errno(device, r, "Failed to read current brightness: %m");
value = strdup(curval);
if (!value)
return log_oom();
} else if (r < 0)
return log_error_errno(r, "Failed to read %s: %m", saved);
(void) clamp_brightness(device, false, max_brightness, &brightness);
}
if (clamp)
(void) clamp_brightness(device, &value, max_brightness);
r = sd_device_set_sysattr_value(device, "brightness", value);
r = sd_device_set_sysattr_valuef(device, "brightness", "%u", brightness);
if (r < 0)
return log_device_error_errno(device, r, "Failed to write system 'brightness' attribute: %m");
} else if (streq(argv[1], "save")) {
const char *value;
if (validate_device(device) == 0) {
(void) unlink(saved);
return 0;
}
r = read_brightness(device, &value);
r = read_brightness(device, max_brightness, &brightness);
if (r < 0)
return log_device_error_errno(device, r, "Failed to read current brightness: %m");
r = write_string_file(saved, value, WRITE_STRING_FILE_CREATE);
r = write_string_filef(saved, WRITE_STRING_FILE_CREATE, "%u", brightness);
if (r < 0)
return log_device_error_errno(device, r, "Failed to write %s: %m", saved);

1
src/libsystemd/libsystemd.sym
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@ -732,4 +732,5 @@ global:
sd_device_get_current_tag_first;
sd_device_get_current_tag_next;
sd_device_has_current_tag;
sd_device_set_sysattr_valuef;
} LIBSYSTEMD_246;

23
src/libsystemd/sd-device/sd-device.c
View File

@ -1979,3 +1979,26 @@ _public_ int sd_device_set_sysattr_value(sd_device *device, const char *sysattr,
return 0;
}
_public_ int sd_device_set_sysattr_valuef(sd_device *device, const char *sysattr, const char *format, ...) {
_cleanup_free_ char *value = NULL;
va_list ap;
int r;
assert_return(device, -EINVAL);
assert_return(sysattr, -EINVAL);
if (!format) {
device_remove_sysattr_value(device, sysattr);
return 0;
}
va_start(ap, format);
r = vasprintf(&value, format, ap);
va_end(ap);
if (r < 0)
return -ENOMEM;
return sd_device_set_sysattr_value(device, sysattr, value);
}

1
src/systemd/sd-device.h
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@ -79,6 +79,7 @@ int sd_device_get_property_value(sd_device *device, const char *key, const char
int sd_device_get_sysattr_value(sd_device *device, const char *sysattr, const char **_value);
int sd_device_set_sysattr_value(sd_device *device, const char *sysattr, const char *value);
int sd_device_set_sysattr_valuef(sd_device *device, const char *sysattr, const char *format, ...) _sd_printf_(3, 4);
/* device enumerator */