From a81cb9305e55dbcba81dac585ccdc4d086a1a9fe Mon Sep 17 00:00:00 2001 From: "Milton D. Miller II" Date: Mon, 7 Mar 2016 17:46:28 -0600 Subject: init: Increase fidelity of u-boot environment parsing Deleting a variable with a long value exposed a duplicate openbmcinitdownloadurl variable resulting in two lines in the url file, and wget was not happy. The u-boot environment ends with a double NUL character like many operating environments. Using strings to separate on the NUL bytes was loosing this information. The fw_printenv command does not clear the remainder of the environment when deleting variables. Instead it just makes sure it is terminated with a double NUL byte. Switch from strings to tr to separate the strings. Translate NL to CR to avoid false matches, and use sed to detect a blank line. Also use tail to skip over the CRC bytes. We don't have the config file to know if a flag exists so assume 1 copy for now. Signed-off-by: Milton Miller --- .../obmc-phosphor-initfs/files/obmc-init.sh | 25 ++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-init.sh b/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-init.sh index 4f24246eb..c37b3d53d 100644 --- a/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-init.sh +++ b/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-init.sh @@ -44,17 +44,30 @@ probe_fs_type() { echo ${fst:=jffs2} } -# This fw_get_env_var is a simple but slightly broken version of fw_printenv: +# This fw_get_env_var is a possibly broken version of fw_printenv that +# does not check the crc or flag byte. # The u-boot environemnt starts with a crc32, followed by a flag byte # when a redundannt environment is configured, followed by var=value\0 sets. # The flag byte for nand is a 1 byte counter; for nor it is a 1 or 0 byte. -# The crc and/or nand flag byte can contain printable characters and be -# considered part of the first string and parsed as part of the variable -# name. In addition a variable could have a "\n" embedded in it, this code -# would split that variable. Ignore for now, the last set var is at the end. get_fw_env_var() { - strings /run/fw_env | sed -ne "s/^$1=//p" + # do we have 1 or 2 copies of the environment? + # count non-blank non-comment lines + # copies=$(grep -v ^# /etc/fw_env.config | grep -c [::alnum::]) + # ... we could if we had the fw_env.config in the initramfs + copies=1 + + # * Change \n to \r and \0 to \n + # * Skip to the 5th byte to skip over crc + # * then skip to the first or 2nd byte to skip over flag if it exists + # * stop parsing at first empty line corresponding to the + # double \0 at the end of the environment. + # * print the value of the variable name passed as argument + + cat /run/fw_env | + tr '\n\000' '\r\n' | + tail -c +5 | tail -c +${copies-1} | + sed -ne '/^$/,$d' -e "s/^$1=//p" } setup_resolv() { -- cgit v1.2.1