Refactor reading of Android properties
diff --git a/src/arm/android/api.h b/src/arm/android/api.h
index 22b2abc..17c9f19 100644
--- a/src/arm/android/api.h
+++ b/src/arm/android/api.h
@@ -25,7 +25,7 @@
cpuinfo_android_chipset_property_max,
};
-bool cpuinfo_arm_android_parse_properties(struct cpuinfo_android_properties properties[restrict static 1]);
+void cpuinfo_arm_android_parse_properties(struct cpuinfo_android_properties properties[restrict static 1]);
struct cpuinfo_arm_chipset cpuinfo_arm_android_decode_chipset(
diff --git a/src/arm/android/properties.c b/src/arm/android/properties.c
index a55037d..ba188a9 100644
--- a/src/arm/android/properties.c
+++ b/src/arm/android/properties.c
@@ -4,7 +4,7 @@
#include <stddef.h>
#include <string.h>
-#include <dlfcn.h>
+#include <sys/system_properties.h>
#include <linux/api.h>
#include <arm/android/api.h>
@@ -13,115 +13,7 @@
#if CPUINFO_MOCK
#include <cpuinfo-mock.h>
-#endif
-
-/*
- * Size, in chars, of the on-stack buffer used for parsing lines of /system/build.prop
- * This is also the limit on the length of a single line.
- */
-#define BUFFER_SIZE 1024
-
-/*
- * Decode a single line of /system/build.prop information.
- * Lines have format <key>=<value>
- * An truncated example of /system/build.prop (from Galaxy S7):
- *
- * # ro.product.cpu.abi and ro.product.cpu.abi2 are obsolete,
- * # use ro.product.cpu.abilist instead.
- * ro.product.cpu.abi=arm64-v8a
- * ro.product.cpu.abilist=arm64-v8a,armeabi-v7a,armeabi
- * ro.product.cpu.abilist32=armeabi-v7a,armeabi
- * ro.product.cpu.abilist64=arm64-v8a
- * ro.product.manufacturer=samsung
- */
-static bool parse_line(
- const char* line_start,
- const char* line_end,
- struct cpuinfo_android_properties properties[restrict static 1],
- uint64_t line_number)
-{
- /* Minimal valid line length is 3 characters: 1-character key, '=', 1-character value. */
- const size_t line_length = line_end - line_start;
- if (line_length < 3) {
- return true;
- }
-
- /* Lines starting with '#' are comments */
- if (line_start[0] == '#') {
- return true;
- }
-
- /* Search for '=' on the line. */
- const char* separator = line_start;
- for (; separator != line_end; separator++) {
- if (*separator == '=') {
- break;
- }
- }
- /* Skip line if no '=' separator was found. */
- if (separator == line_end) {
- return true;
- }
-
- /* Skip leading spaces in value part. */
- const char* value_start = separator + 1;
- for (; value_start != line_end; value_start++) {
- if (*value_start != ' ') {
- break;
- }
- }
- /* Value part contains nothing but spaces. Skip line. */
- if (value_start == line_end) {
- return true;
- }
-
- /* Skip trailing spaces in value part (if any) */
- const char* value_end = line_end;
- for (; value_end != value_start; value_end--) {
- if (value_end[-1] != ' ') {
- break;
- }
- }
-
- const size_t key_length = separator - line_start;
- const size_t value_length = value_end - value_start;
- const size_t limited_value_length = (value_length >= CPUINFO_BUILD_PROP_VALUE_MAX) ?
- CPUINFO_BUILD_PROP_VALUE_MAX - 1 : value_length;
- switch (key_length) {
- case 11:
- if (memcmp(line_start, "ro.chipname", key_length) == 0) {
- memcpy(properties->ro_chipname, value_start, limited_value_length);
- cpuinfo_log_debug("parsed ro.chipname = \"%s\"",
- properties->ro_chipname);
- }
- break;
- case 16:
- if (memcmp(line_start, "ro.product.board", key_length) == 0) {
- memcpy(properties->ro_product_board, value_start, limited_value_length);
- cpuinfo_log_debug("parsed ro.product.board = \"%s\"",
- properties->ro_product_board);
- }
- break;
- case 17:
- if (memcmp(line_start, "ro.board.platform", key_length) == 0) {
- memcpy(properties->ro_board_platform, value_start, limited_value_length);
- cpuinfo_log_debug("parsed ro.board.platform = \"%s\"",
- properties->ro_board_platform);
- }
- break;
- case 20:
- if (memcmp(line_start, "ro.mediatek.platform", key_length) == 0) {
- memcpy(properties->ro_mediatek_platform, value_start, limited_value_length);
- cpuinfo_log_debug("parsed ro.mediatek.platform = \"%s\"",
- properties->ro_mediatek_platform);
- }
- break;
- }
- return true;
-}
-
-#if CPUINFO_MOCK
static struct cpuinfo_mock_property* cpuinfo_mock_properties = NULL;
void CPUINFO_ABI cpuinfo_mock_android_properties(struct cpuinfo_mock_property* properties) {
@@ -129,102 +21,39 @@
cpuinfo_mock_properties = properties;
}
- static int mock_system_property_get(const char* key, char* value) {
- for (const struct cpuinfo_mock_property* prop = cpuinfo_mock_properties; prop->key != NULL; prop++) {
- if (strncmp(key, prop->key, CPUINFO_BUILD_PROP_NAME_MAX) == 0) {
- strncpy(value, prop->value, CPUINFO_BUILD_PROP_VALUE_MAX);
- return (int) strnlen(prop->value, CPUINFO_BUILD_PROP_VALUE_MAX);
+ static int cpuinfo_android_property_get(const char* key, char* value) {
+ if (cpuinfo_mock_properties != NULL) {
+ for (const struct cpuinfo_mock_property* prop = cpuinfo_mock_properties; prop->key != NULL; prop++) {
+ if (strncmp(key, prop->key, CPUINFO_BUILD_PROP_NAME_MAX) == 0) {
+ strncpy(value, prop->value, CPUINFO_BUILD_PROP_VALUE_MAX);
+ return (int) strnlen(prop->value, CPUINFO_BUILD_PROP_VALUE_MAX);
+ }
}
}
*value = '\0';
return 0;
}
-
- static bool cpuinfo_arm_android_query_properties(struct cpuinfo_android_properties properties[restrict static 1]) {
- if (cpuinfo_mock_properties == NULL) {
- return false;
- }
-
- const int ro_product_board_length =
- mock_system_property_get("ro.product.board", properties->ro_product_board);
- cpuinfo_log_debug("read ro.product.board = \"%.*s\"",
- ro_product_board_length, properties->ro_product_board);
-
- const int ro_board_platform_length =
- mock_system_property_get("ro.board.platform", properties->ro_board_platform);
- cpuinfo_log_debug("read ro.board.platform = \"%.*s\"",
- ro_board_platform_length, properties->ro_board_platform);
-
- const int ro_mediatek_platform_length =
- mock_system_property_get("ro.mediatek.platform", properties->ro_mediatek_platform);
- cpuinfo_log_debug("read ro.mediatek.platform = \"%.*s\"",
- ro_mediatek_platform_length, properties->ro_mediatek_platform);
-
- const int ro_chipname_length =
- mock_system_property_get("ro.chipname", properties->ro_chipname);
- cpuinfo_log_debug("read ro.chipname = \"%.*s\"",
- ro_chipname_length, properties->ro_chipname);
-
- return true;
- }
#else
- /*
- * Function pointer declaration for
- * int __system_property_get(const char *name, char *value)
- * function from sys/system_properties.h header. Google's stance on whether function is part of a stable API is unclear:
- * it was removed from public API in some NDK versions, and then added back. In practice, libc.so has this symbol,
- * so we dynamically locate this function using dlopen + dlsym.
- */
- typedef int (*system_property_get_ptr)(const char[], char[]);
-
- static bool cpuinfo_arm_android_query_properties(struct cpuinfo_android_properties properties[restrict static 1]) {
- void* libc = dlopen("libc.so", RTLD_LAZY);
- if (libc == NULL) {
- cpuinfo_log_warning("failed to dlopen libc.so; fallback to reading /system/build.prop for Android properties");
- return false;
- }
-
- system_property_get_ptr system_property_get = (system_property_get_ptr) dlsym(libc, "__system_property_get");
- if (system_property_get == NULL) {
- cpuinfo_log_warning(
- "could not find __system_property_get in libc.so: "
- "fallback to reading /system/build.prop for Android properties");
- goto cleanup;
- }
-
- const int ro_product_board_length = system_property_get("ro.product.board", properties->ro_product_board);
- cpuinfo_log_debug("read ro.product.board = \"%.*s\"", ro_product_board_length, properties->ro_product_board);
-
- const int ro_board_platform_length = system_property_get("ro.board.platform", properties->ro_board_platform);
- cpuinfo_log_debug("read ro.board.platform = \"%.*s\"", ro_board_platform_length, properties->ro_board_platform);
-
- const int ro_mediatek_platform_length =
- system_property_get("ro.mediatek.platform", properties->ro_mediatek_platform);
- cpuinfo_log_debug("read ro.mediatek.platform = \"%.*s\"",
- ro_mediatek_platform_length, properties->ro_mediatek_platform);
-
- const int ro_chipname_length = system_property_get("ro.chipname", properties->ro_chipname);
- cpuinfo_log_debug("read ro.chipname = \"%.*s\"", ro_chipname_length, properties->ro_chipname);
-
- cleanup:
- dlclose(libc);
- return system_property_get != NULL;
+ static inline int cpuinfo_android_property_get(const char* key, char* value) {
+ return __system_property_get(key, value);
}
#endif
-bool cpuinfo_arm_android_parse_properties(struct cpuinfo_android_properties properties[restrict static 1]) {
- memset(properties, 0, sizeof(struct cpuinfo_android_properties));
+void cpuinfo_arm_android_parse_properties(struct cpuinfo_android_properties properties[restrict static 1]) {
+ const int ro_product_board_length =
+ cpuinfo_android_property_get("ro.product.board", properties->ro_product_board);
+ cpuinfo_log_debug("read ro.product.board = \"%.*s\"", ro_product_board_length, properties->ro_product_board);
- /*
- * First, try to use __system_property_get, which is widely supported. Whether is it a part of public API is
- * debatable: Android 7.0 release note suggest to use __system_property_get instead of property_get from
- * libcutils.so, but it was removed from headers in some NDK versions on ARM64.
- * If __system_property_get can't be located, fallback to parsing /system/build.prop file. This method is
- * recommended by an Android engineer (see https://stackoverflow.com/a/28416743), but doesn't work on Android Oreo
- * (where the /system/build.prop file is not readable for non-root users) and some Huawei devices (where
- * /system/build.prop contains empty strings for some properties of interest).
- */
- return cpuinfo_arm_android_query_properties(properties) ||
- cpuinfo_linux_parse_multiline_file("/system/build.prop", BUFFER_SIZE,
- (cpuinfo_line_callback) parse_line, properties);
+ const int ro_board_platform_length =
+ cpuinfo_android_property_get("ro.board.platform", properties->ro_board_platform);
+ cpuinfo_log_debug("read ro.board.platform = \"%.*s\"", ro_board_platform_length, properties->ro_board_platform);
+
+ const int ro_mediatek_platform_length =
+ cpuinfo_android_property_get("ro.mediatek.platform", properties->ro_mediatek_platform);
+ cpuinfo_log_debug("read ro.mediatek.platform = \"%.*s\"",
+ ro_mediatek_platform_length, properties->ro_mediatek_platform);
+
+ const int ro_chipname_length =
+ cpuinfo_android_property_get("ro.chipname", properties->ro_chipname);
+ cpuinfo_log_debug("read ro.chipname = \"%.*s\"", ro_chipname_length, properties->ro_chipname);
}