From 2cb3604727ad4eb53f9c6b44492222bb72118811 Mon Sep 17 00:00:00 2001
From: Eugene Syromiatnikov <esyr@redhat.com>
Date: Wed, 17 May 2023 14:01:55 +0200
Subject: [PATCH] find-provides.ksyms, find-requires.ksyms: rewrite section
 data matching

Currently, it just matches the 2nd to 5th fields with awk, which leads
to occasional capturing of some garbage at the end of the section data
and minor issues when supplying it to the symbol extracting awk script:

    awk: cmd. line:1: (FILENAME=- FNR=19) fatal: argument index with `$' must be > 0
    awk: warning: escape sequence `\.' treated as plain `.'
    awk: cmd. line:1: (FILENAME=- FNR=9) fatal: not enough arguments to satisfy format string
    	`78b624dbc125415351be965ex.$..%ASQ..^'
    	                              ^ ran out for this one

While at it, also eliminate grep and sed calls (with the pair of awk and
sed being the most offending).

* find-provides.ksyms: Generate part of the awk script that performs
the byte reversal based on the endianness in the readelf -h output,
inject it into the awk script;  use substr for matching parts
of the section data instead of fields.
* find-requires.ksyms (all_provides): Likewise.

Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
---
 find-provides.ksyms | 11 +++++------
 find-requires.ksyms | 11 +++++------
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/find-provides.ksyms b/find-provides.ksyms
index c666a9d..2c396f9 100755
--- a/find-provides.ksyms
+++ b/find-provides.ksyms
@@ -50,12 +50,11 @@ for module in $(grep -E '/lib/modules/.+\.ko(\.gz|\.bz2|\.xz|\.zst)?$') "$@"; do
         | while read -r sectname; do
             [ -n "$sectname" ] || continue
 
-            ELFSECTDATA=$(readelf -R "$sectname" "$module" | awk '/0x/{printf $2$3$4$5}')
-            if [[ -n $(readelf -h $module | grep "little endian") ]]; then
-                SECTDATA=$(echo $ELFSECTDATA | sed 's/\(..\)\(..\)\(..\)\(..\)/\4\3\2\1/g')
-            else
-                SECTDATA=$ELFSECTDATA
-            fi
+            revbytes=""
+            kmod_elf_hdr="$(readelf -h "$module")"
+            [ "x$kmod_elf_hdr" = "x${kmod_elf_hdr%Data:*little endian*}" ] ||
+                revbytes='a = gensub(/(..)(..)(..)(..)/, "\\4\\3\\2\\1", "g", a);'
+            SECTDATA=$(readelf -R "$sectname" "$module" | awk '/^  0x[0-9a-f]{8}/{ a = substr($0, 14, 8) substr($0, 23, 8) substr($0, 32, 8) substr($0, 41, 8); '"$revbytes"' printf("%s", a); }')
 
             objdump -t "$module" \
             | awk \
diff --git a/find-requires.ksyms b/find-requires.ksyms
index 565cc90..7ece283 100755
--- a/find-requires.ksyms
+++ b/find-requires.ksyms
@@ -52,12 +52,11 @@ all_provides() {
             | while read -r sectname; do
                 [ -n "$sectname" ] || continue
 
-                ELFSECTDATA=$(readelf -R "$sectname" "$module" | awk '/0x/{printf $2$3$4$5}')
-                if [[ -n $(readelf -h "$module" | grep "little endian") ]]; then
-                    SECTDATA=$(echo $ELFSECTDATA | sed 's/\(..\)\(..\)\(..\)\(..\)/\4\3\2\1/g')
-                else
-                    SECTDATA=$ELFSECTDATA
-                fi
+                revbytes=""
+                kmod_elf_hdr="$(readelf -h "$module")"
+                [ "x$kmod_elf_hdr" = "x${kmod_elf_hdr%Data:*little endian*}" ] ||
+                    revbytes='a = gensub(/(..)(..)(..)(..)/, "\\4\\3\\2\\1", "g", a);'
+                SECTDATA=$(readelf -R "$sectname" "$module" | awk '/^  0x[0-9a-f]{8}/{ a = substr($0, 14, 8) substr($0, 23, 8) substr($0, 32, 8) substr($0, 41, 8); '"$revbytes"' printf("%s", a); }')
 
                 objdump -t "$module" \
                 | awk \