Prevent truncating log tag name #83
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The currently hard-coded limit is 23 characters. This limit originates from the pre-Android 7.0 32-character limit on system property names, because Android's `liblog` allows setting the log level at runtime through `log.tag` system properties [1]. The limit meant that "log.tag.SOMETAG" must have been shorter than 32 bytes, leaving 23 bytes for the tag itself. The system property length limitation was removed in [2], so since 2017 it no longer applies, and some Android components already use longer tags [3][4]. This change increases the size of the stack-allocated buffer used for null-terminating the tag to 128 bytes, and adds support for even longer tags by falling back to heap-allocated CString when the tag is longer than that. The fallback path will introduce a performance penalty, but at the same time will allow manual level adjustment via log.tag. system property regardless of the tag length. [1] https://cs.android.com/android/platform/superproject/main/+/main:system/logging/logd/README.property;l=50?q=f:readme.property [2] https://android-review.googlesource.com/c/platform/bionic/+/327226 [3] https://cs.android.com/android/platform/superproject/main/+/main:device/generic/goldfish-opengl/system/codecs/omx/plugin/GoldfishVideoDecoderOMXComponent.cpp;l=20 [4] https://cs.android.com/android/platform/superproject/main/+/main:hardware/interfaces/biometrics/fingerprint/2.2/default/BiometricsFingerprint.cpp;l=16
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The currently hard-coded limit is 23 characters. This limit originates from the pre-Android 7.0 32-character limit on system property names, because Android's
liblogallows setting the log level at runtime throughlog.tagsystem properties [1]. The limit meant that "log.tag.SOMETAG" must have been shorter than 32 bytes, leaving 23 bytes for the tag itself.The system property length limitation was removed in [2], so since 2017 it no longer applies, and some Android components already use longer tags [3][4].
This change increases the size of the stack-allocated buffer used for null-terminating the tag to 128 bytes, and adds support for even longer tags by falling back to heap-allocated CString when the tag is longer than that. The fallback path will introduce a performance penalty, but at the same time will allow manual level adjustment via log.tag. system property regardless of the tag length.
[1] https://cs.android.com/android/platform/superproject/main/+/main:system/logging/logd/README.property;l=50?q=f:readme.property
[2] https://android-review.googlesource.com/c/platform/bionic/+/327226
[3] https://cs.android.com/android/platform/superproject/main/+/main:device/generic/goldfish-opengl/system/codecs/omx/plugin/GoldfishVideoDecoderOMXComponent.cpp;l=20
[4] https://cs.android.com/android/platform/superproject/main/+/main:hardware/interfaces/biometrics/fingerprint/2.2/default/BiometricsFingerprint.cpp;l=16