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IN A] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid Subject: [OpenWrt-Devel] [PATCH v2] package/base-files: caldata: work around dd's limitation X-BeenThere: openwrt-devel@lists.openwrt.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?utf-8?q?Thibaut_VAR=C3=88NE?= Sender: "openwrt-devel" Errors-To: openwrt-devel-bounces+incoming=patchwork.ozlabs.org@lists.openwrt.org tl;dr: dd will silently truncate the output if reading from special files (e.g. sysfs attributes) with a too large bs parameter. This problem was exposed on some RouterBOARD ipq40xx devices which use a caldata payload which is larger than PAGE_SIZE, contrary to all other currently supported RouterBOARD devices: the caldata would fail to properly load with the current scripts. Background: dd doesn't seem to correctly handle read() results that return less than requested data. sysfs attributes have a kernel exchange buffer which is at most PAGE_SIZE big, so only 1 page can be read() at a time. In this case, if bs is larger than PAGE_SIZE, dd will silently truncate blocks to PAGE_SIZE. With the current scripts using bs= count=1, the data is truncated to PAGE_SIZE as soon as the requested exceeds this value. This commit works around this problem by using `cat` in the caldata routines that can read from a file (routines that read from mtd devices are untouched). cat correctly handles partial read requests. The output is then piped to dd with the same parameters as before, to ensure that the resulting file remains exactly the same. This is a simple workaround, the downside is that it uses a pipe and one more executable, and therefore has a larger memory footprint and is slower. This is deemed acceptable considering these routines are only used at boot time. Tested-by: Robert Marko Signed-off-by: Thibaut VARÈNE --- v2: leave a comment in scripts --- package/base-files/Makefile | 2 +- package/base-files/files/lib/functions/caldata.sh | 8 +++++--- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/package/base-files/Makefile b/package/base-files/Makefile index d8e7c31878..5fb275533d 100644 --- a/package/base-files/Makefile +++ b/package/base-files/Makefile @@ -12,7 +12,7 @@ include $(INCLUDE_DIR)/version.mk include $(INCLUDE_DIR)/feeds.mk PKG_NAME:=base-files -PKG_RELEASE:=220 +PKG_RELEASE:=221 PKG_FLAGS:=nonshared PKG_FILE_DEPENDS:=$(PLATFORM_DIR)/ $(GENERIC_PLATFORM_DIR)/base-files/ diff --git a/package/base-files/files/lib/functions/caldata.sh b/package/base-files/files/lib/functions/caldata.sh index 6862da7164..e22c7d27e6 100644 --- a/package/base-files/files/lib/functions/caldata.sh +++ b/package/base-files/files/lib/functions/caldata.sh @@ -64,7 +64,8 @@ caldata_from_file() { [ -n "$target" ] || target=/lib/firmware/$FIRMWARE - dd if=$source of=$target iflag=skip_bytes bs=$count skip=$offset count=1 2>/dev/null || \ + # dd doesn't handle partial reads from special files: use cat + cat $source | dd of=$target iflag=skip_bytes bs=$count skip=$offset count=1 2>/dev/null || \ caldata_die "failed to extract calibration data from $source" } @@ -73,13 +74,14 @@ caldata_sysfsload_from_file() { local offset=$(($2)) local count=$(($3)) + # dd doesn't handle partial reads from special files: use cat # test extract to /dev/null first - dd if=$source of=/dev/null iflag=skip_bytes bs=$count skip=$offset count=1 2>/dev/null || \ + cat $source | dd of=/dev/null iflag=skip_bytes bs=$count skip=$offset count=1 2>/dev/null || \ caldata_die "failed to extract calibration data from $source" # can't fail now echo 1 > /sys/$DEVPATH/loading - dd if=$source of=/sys/$DEVPATH/data iflag=skip_bytes bs=$count skip=$offset count=1 2>/dev/null + cat $source | dd of=/sys/$DEVPATH/data iflag=skip_bytes bs=$count skip=$offset count=1 2>/dev/null echo 0 > /sys/$DEVPATH/loading }