#!/bin/bash

# Auto-generating dependencies for glibc development snapshots.

#

# A glibc development snapshot (say version 2.33.9000) may define

# symbols in its under-development symbol version (GLIBC_2.34).  RPM

# automatically derives RPM dependencies such as

# libc.so.6(GLIBC_2.34)(64bit) from that.  While the GLIBC_2.34

# version is under development, these dependencies may be inaccurate

# and could be satisfied by glibc RPM package versions that lack the

# symbols because they were created from an earlier development

# snapshot that had some other GLIBC_2.34 symbols.  Therefore, if the

# latest, under-development ELF symbol version is detected, this

# dependency generator adds an explicit RPM dependencies on the glibc

# packaging version against which an RPM package is built.

#

# This script runs for the glibc build itself.  In this case, it may

# produce a >= dependency on the build-time glibc, but there will also

# be an (potentially indirect) = dependency, which takes precedence.

set -e

set -o pipefail

searching=true

# Pre-filter using eu-elfclassify, to skip kernel modules.

eu-elfclassify --loadable --file --stdin --print | while read path; do

    # Assume that all dynamically linked objects depend on glibc in

    # some way.

    if $searching; then

	# Undefined symbols within latest, under-development

	# (changing) symbol versions trigger the versioned RPM

	# dependency.  Do not use "grep -Eq" to keep reading from the

	# pipe, avoiding a spurious EPIPE error in eu-readelf.

	if eu-readelf -s "$path" \

		| grep -E '\sUNDEF\s.*@''@SYMVER@(\s|$)' >/dev/null

	then

	    echo 'glibc >= @VERSION@-@RELEASE@'

	    # Stop searching after the first match, but keep reading from

	    # the pipe.

	    searching=false

	fi

    fi

done