How do I read BASH parameters correctly from a file?

Question

I have this configuration file in my CI where I'm specifying a header file and some CMAKE flags on one line.

The configuration file looks like this (filelist):

./settings6.h -DMY_COMPILE_FLAGS="-m32 -fstrict-aliasing"
./settings7.h -DMY_FEATURE_1=ON
./settings8.h -DMY_FLAG=ON -DMY_FEATURE_2=ON -DMY_INCLUDE_DIR=/usr/include/

Now, I'm using a bash script to process this configuration file:

#!/bin/bash
SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
while read i; do
    HEADERFILE=$(echo $i | cut -d ' ' -f 1)
    CMAKEFLAGS=$(echo $i | cut -s -d ' ' -f 2-)
    if [[ "$HEADERFILE" == "" ]]; then
        continue
    fi
    CFLAGS="-Werror" cmake "my_build_dir" "$CMAKEFLAGS" -G "Ninja" -DMY_EXTRA_INCLUDE="$SCRIPTDIR/$HEADERFILE" -B"build_env_dir" > /dev/null
    ninja -C "build_env_dir"
done <<ENDOFINPUT
$(grep -v '^#' $SCRIPTDIR/filelist)
ENDOFINPUT

When I have the bash script as above, the line with settings6.h gets processed properly, i.e. the MY_COMPILE_FLAGS are set to -m32 -fstrict-aliasing.

However, settings8.h is failing because the value of MY_FLAG is seen by CMAKE as ON -DMY_FEATURE_2=ON -DMY_INCLUDE_DIR=/usr/include/, so MY_FEATURE_2 and MY_INCLUDE_DIR are not processed correctly.

After googling around a bit, I thought, well, surely a quoting issue, probably I have to remove the quotes around $CMAKEFLAGS like this:

    CFLAGS="-Werror" cmake "my_build_dir" $CMAKEFLAGS -G "Ninja" -DMY_EXTRA_INCLUDE="$SCRIPTDIR/$HEADERFILE" -B"build_env_dir" > /dev/null

In fact, this lets settings8.h work as expected (all three options are processed), but now, settings6.h is suddenly failing since CMAKE complains:

CMake Error: The source directory "/src/-fstrict-aliasing"" does not exist

Can someone guide me please how I read the settings correctly from my filelist so that settings6.h and settings8.h both succeed?

Possible duplicate of stackoverflow.com/questions/12136948/… — tripleee
– tripleee, Commented Nov 22, 2019 at 10:53
@tripleee I actually don't think this is a duplicate: passing $CMAKEFLAGS as array doesn't improve anything. Do you have another suggestion? — eckes
– eckes, Commented Nov 22, 2019 at 11:42
The best proposal I can come up with is to modify your input file format so that you can parse it without eval or other horrible workarounds. Wrapping this in a Makefile comes to mind as one potentially rather elegant workaround. — tripleee
– tripleee, Commented Nov 22, 2019 at 11:44
@tripleee do you have an example (maybe you post it as an answer) how such a file format would look like? — eckes
– eckes, Commented Nov 22, 2019 at 13:26
If you are using cmake anyway I would probably use that for the whole thing, but I'm not familiar enough with it to show you how. — tripleee
– tripleee, Commented Nov 22, 2019 at 14:28

tripleee · Accepted Answer · 2019-11-23 11:21:03Z

1

Here's a Makefile which refactors this into a sequence of recipes.

Cases := $(patsubst %.h,%,$(wildcard ./settings*.h))
all_done := $(patsubst %,.%.done,$(Cases))

.PHONY: all
all: $(all_done)

cases.mk: filelist.txt
    sed 's%^\./%case_%;s% % := %' $< >$@
include cases.mk

.%_done: ./%.h
    CFLAGS="-Werror" cmake "my_build_dir" $(case_$*) -G "Ninja" \
        -DMY_EXTRA_INCLUDE="$<" -B"build_env_dir" > /dev/null
    ninja -C "build_env_dir"

edited Nov 23, 2019 at 11:21

answered Nov 23, 2019 at 8:54

tripleee

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1 Comment

tripleee Over a year ago

Not in a place where I can test this but hopefully this can at least inspire some lateral thinking...

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