fix glibc linkage on debian again

4 files changed, 157 insertions, 119 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f2cf5cf..451465d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## [Unreleased]
+
+### Fixed
+
+* `rbw` should once again be usable on systems with glibc-2.28 (such as Debian
+  stable).
+
 ## [0.5.1] - 2020-12-02
 
 ### Fixed
diff --git a/Makefile b/Makefile
index 937b1ab..fc783c9 100644
--- a/Makefile
+++ b/Makefile
@@ -12,8 +12,10 @@ build:
 
 release:
 	@cargo build --release --all-targets
-	@./bin/remove-glibc-2.29-use ./target/release/rbw
+	@./build/fix-glibc-function-versions ./target/release/rbw
+	@./build/fix-glibc-function-versions ./target/release/rbw-agent
 	@mv ./target/release/rbw.new ./target/release/rbw
+	@mv ./target/release/rbw-agent.new ./target/release/rbw-agent
 .PHONY: release
 
 test:
diff --git a/bin/remove-glibc-2.29-use b/bin/remove-glibc-2.29-use
deleted file mode 100755
index c23b7a6..0000000
--- a/bin/remove-glibc-2.29-use
+++ /dev/null
@@ -1,118 +0,0 @@
-#!/usr/bin/env perl
-use strict;
-use warnings;
-use 5.020;
-use experimental 'signatures';
-no warnings 'experimental::signatures';
-
-# see http://www.lightofdawn.org/wiki/wiki.cgi/NewAppsOnOldGlibc for details
-
-# as of currently, only `log2` is being used from GLIBC_2.29, and a
-# corresponding version from GLIBC_2.2.5 does exist, so we can just swap it
-# out.
-
-my $bin = $ARGV[0];
-
-system("readelf -s $bin | grep -q GLIBC_2.29");
-if ($?) {
-    die "no symbols from GLIBC_2.29 found, skipping\n";
-}
-
-my %readelf_v = parse_readelf_v($bin);
-my %readelf_s = parse_readelf_s($bin);
-
-if ($readelf_s{'log2@GLIBC_2.29'}{ver} != $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.29'}{ver}) {
-    die "log2 doesn't appear to use the symbol version from GLIBC_2.29\n";
-}
-
-my $bin_contents = do {
-    local $/;
-    open my $bin_fh, '<', $bin or die "couldn't open $bin: $!";
-    <$bin_fh>
-};
-
-my $gnu_version_r_offset = $readelf_v{'.gnu.version_r'}{offset};
-my $glibc_229_offset = $gnu_version_r_offset + $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.29'}{offset};
-my $glibc_225_offset = $gnu_version_r_offset + $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.2.5'}{offset};
-
-# we could just make the GLIBC_2.29 symbol weak (as described in the above
-# page), but that causes a warning to be printed every time you run the binary,
-# which is obnoxious
-
-# use constant VER_FLG_WEAK => 0x02;
-# my $prev_glibc_229_flags = substr $bin_contents, $glibc_229_offset + 0x04, 2, pack('s', VER_FLG_WEAK);
-# if (unpack('s', $prev_glibc_229_flags) != 0) {
-#     die "GLIBC_2.29 did not have flags set to 0\n";
-# }
-
-# instead, we overwrite vna_hash, vna_flags, vna_other, vna_name with the 2.2.5
-# versions (but leave vna_next the same) - this causes there to be two entries
-# describing GLIBC_2.2.5, but this appears to be harmless
-substr($bin_contents, $glibc_229_offset + 0x00, 12, substr($bin_contents, $glibc_225_offset + 0x00, 12));
-
-my $gnu_version_offset = $readelf_v{'.gnu.version'}{offset};
-my $log2_offset = $gnu_version_offset + 2 * $readelf_s{'log2@GLIBC_2.29'}{num};
-
-my $prev_log2_version = substr $bin_contents, $log2_offset, 2, pack('s', $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.2.5'}{ver});
-if (unpack('s', $prev_log2_version) != $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.29'}{ver}) {
-    die "log2 doesn't appear to use the symbol version from GLIBC_2.29\n";
-}
-
-open my $fh, '>', "$bin.new" or die "couldn't open $bin.new: $!";
-print $fh $bin_contents;
-chmod 0755, "$bin.new";
-
-my $remaining = `readelf -s $bin.new | grep GLIBC_2.29`;
-if (!$?) {
-    die "additional symbols from GLIBC_2.29 found:\n$remaining\n";
-}
-
-sub parse_readelf_s($bin) {
-    my $readelf = `readelf -s $bin`;
-
-    my %ret;
-    for my $line (split "\n", $readelf) {
-        if ($line =~ /^ *[0-9]+:/) {
-            my ($num, $value, $size, $type, $bind, $vis, $ndx, $name, $ver) = split ' ', $line;
-            if (defined $ver) {
-                ($ver) = $ver =~ /\((.*)\)/;
-            }
-            if (defined $num) {
-                ($num) = $num =~ /(.*):/;
-            }
-            $ret{$name} = {
-                num => $num,
-                ver => $ver,
-            }
-        }
-    }
-
-    %ret
-}
-
-sub parse_readelf_v($bin) {
-    my $readelf = `readelf -V $bin`;
-
-    my $section;
-    my $file;
-    my %ret;
-    for my $line (split "\n", $readelf) {
-        if ($line =~ /^Version (?:symbols|needs) section '([^']+)'/) {
-            $section = $1;
-        }
-        if ($line =~ /^ Addr: (?:[^ ]+)  Offset: ([^ ]+)/) {
-            $ret{$section}{offset} = hex($1);
-        }
-        if ($line =~ /^  [^:]+: Version: [^ ]+  File: ([^ ]+)/) {
-            $file = $1;
-        }
-        if ($line =~ /^  ([^:]+):   Name: ([^ ]+)  Flags: (?:[^ ]+)  Version: (.*)/) {
-            $ret{$section}{$file}{$2} = {
-                offset => hex($1),
-                ver => $3,
-            };
-        }
-    }
-
-    %ret
-}
diff --git a/build/fix-glibc-function-versions b/build/fix-glibc-function-versions
new file mode 100755
index 0000000..213687a
--- /dev/null
+++ b/build/fix-glibc-function-versions
@@ -0,0 +1,147 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use 5.020;
+use experimental 'signatures';
+no warnings 'experimental::signatures';
+
+# see http://www.lightofdawn.org/wiki/wiki.cgi/NewAppsOnOldGlibc for details
+
+# as of currently, only `log2` is being used from GLIBC_2.29 and
+# `pthread_sigmask` and `pthread_getattr_np` is being used from GLIBC_2.32, and
+# corresponding versions from GLIBC_2.2.5 do exist, so we can just swap them
+# out.
+
+my $bin = $ARGV[0];
+
+system("readelf -sW $bin | grep -q 'GLIBC_2.\\(29\\|32\\)'");
+if ($?) {
+    warn "no symbols from GLIBC_2.29 or GLIBC_2.32 found, skipping\n";
+    exit(0)
+}
+
+my %readelf_v = parse_readelf_v($bin);
+my %readelf_s = parse_readelf_s($bin);
+
+my $bin_contents = do {
+    local $/;
+    open my $bin_fh, '<', $bin or die "couldn't open $bin: $!";
+    <$bin_fh>
+};
+
+# we could just make the GLIBC_2.29 symbol weak (as described in the above
+# page), but that causes a warning to be printed every time you run the binary,
+# which is obnoxious
+
+# use constant VER_FLG_WEAK => 0x02;
+# my $prev_glibc_229_flags = substr $bin_contents, $glibc_229_offset + 0x04, 2, pack('s', VER_FLG_WEAK);
+# if (unpack('s', $prev_glibc_229_flags) != 0) {
+#     die "GLIBC_2.29 did not have flags set to 0\n";
+# }
+
+# instead, we overwrite vna_hash, vna_flags, vna_other, vna_name with the 2.2.5
+# versions (but leave vna_next the same) - this causes there to be multiple
+# entries describing GLIBC_2.2.5, but this appears to be harmless
+my $gnu_version_r_offset = $readelf_v{'.gnu.version_r'}{offset};
+my $fix_libc = defined($readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.32'}{offset});
+my $fix_libm = defined($readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.29'}{offset});
+
+if ($fix_libc) {
+    my $glibc_232_libc_offset = $gnu_version_r_offset + $readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.32'}{offset};
+    my $glibc_225_libc_offset = $gnu_version_r_offset + $readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.2.5'}{offset};
+    substr($bin_contents, $glibc_232_libc_offset + 0x00, 12, substr($bin_contents, $glibc_225_libc_offset + 0x00, 12));
+}
+
+if ($fix_libm) {
+    my $glibc_229_libm_offset = $gnu_version_r_offset + $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.29'}{offset};
+    my $glibc_225_libm_offset = $gnu_version_r_offset + $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.2.5'}{offset};
+    substr($bin_contents, $glibc_229_libm_offset + 0x00, 12, substr($bin_contents, $glibc_225_libm_offset + 0x00, 12));
+}
+
+my $gnu_version_offset = $readelf_v{'.gnu.version'}{offset};
+my $fix_log2 = defined($readelf_s{'log2@GLIBC_2.29'}{ver}) && $readelf_s{'log2@GLIBC_2.29'}{ver} == $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.29'}{ver};
+my $fix_pthread_sigmask = defined($readelf_s{'pthread_sigmask@GLIBC_2.32'}{ver}) && $readelf_s{'pthread_sigmask@GLIBC_2.32'}{ver} == $readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.32'}{ver};
+my $fix_pthread_getattr_np = defined($readelf_s{'pthread_getattr_np@GLIBC_2.32'}{ver}) && $readelf_s{'pthread_getattr_np@GLIBC_2.32'}{ver} == $readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.32'}{ver};
+
+if ($fix_log2) {
+    my $log2_offset = $gnu_version_offset + 2 * $readelf_s{'log2@GLIBC_2.29'}{num};
+    my $prev_log2_version = substr $bin_contents, $log2_offset, 2, pack('s', $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.2.5'}{ver});
+    if (unpack('s', $prev_log2_version) != $readelf_v{'.gnu.version_r'}{'libm.so.6'}{'GLIBC_2.29'}{ver}) {
+        die "log2 doesn't appear to use the symbol version from GLIBC_2.29\n";
+    }
+}
+
+if ($fix_pthread_sigmask) {
+    my $pthread_sigmask_offset = $gnu_version_offset + 2 * $readelf_s{'pthread_sigmask@GLIBC_2.32'}{num};
+    my $prev_pthread_sigmask_version = substr $bin_contents, $pthread_sigmask_offset, 2, pack('s', $readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.2.5'}{ver});
+    if (unpack('s', $prev_pthread_sigmask_version) != $readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.32'}{ver}) {
+        die "pthread_sigmask doesn't appear to use the symbol version from GLIBC_2.32\n";
+    }
+}
+
+if ($fix_pthread_getattr_np) {
+    my $pthread_getattr_np_offset = $gnu_version_offset + 2 * $readelf_s{'pthread_getattr_np@GLIBC_2.32'}{num};
+    my $prev_pthread_getattr_np_version = substr $bin_contents, $pthread_getattr_np_offset, 2, pack('s', $readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.2.5'}{ver});
+    if (unpack('s', $prev_pthread_getattr_np_version) != $readelf_v{'.gnu.version_r'}{'libc.so.6'}{'GLIBC_2.32'}{ver}) {
+        die "pthread_getattr_np doesn't appear to use the symbol version from GLIBC_2.32\n";
+    }
+}
+
+open my $fh, '>', "$bin.new" or die "couldn't open $bin.new: $!";
+print $fh $bin_contents;
+chmod 0755, "$bin.new";
+
+my $remaining = `readelf -sW $bin.new | grep 'GLIBC_2.\\(29\\|32\\)'`;
+if (!$?) {
+    die "additional symbols from GLIBC_2.29 or GLIBC_2.32 found:\n$remaining\n";
+}
+
+sub parse_readelf_s($bin) {
+    my $readelf = `readelf -sW $bin`;
+
+    my %ret;
+    for my $line (split "\n", $readelf) {
+        if ($line =~ /^ *[0-9]+:/) {
+            my ($num, $value, $size, $type, $bind, $vis, $ndx, $name, $ver) = split ' ', $line;
+            if (defined $ver) {
+                ($ver) = $ver =~ /\((.*)\)/;
+            }
+            if (defined $num) {
+                ($num) = $num =~ /(.*):/;
+            }
+            $ret{$name} = {
+                num => $num,
+                ver => $ver,
+            }
+        }
+    }
+
+    %ret
+}
+
+sub parse_readelf_v($bin) {
+    my $readelf = `readelf -V $bin`;
+
+    my $section;
+    my $file;
+    my %ret;
+    for my $line (split "\n", $readelf) {
+        if ($line =~ /^Version (?:symbols|needs) section '([^']+)'/) {
+            $section = $1;
+        }
+        if ($line =~ /^ Addr: (?:[^ ]+)  Offset: ([^ ]+)/) {
+            $ret{$section}{offset} = hex($1);
+        }
+        if ($line =~ /^  [^:]+: Version: [^ ]+  File: ([^ ]+)/) {
+            $file = $1;
+        }
+        if ($line =~ /^  ([^:]+):   Name: ([^ ]+)  Flags: (?:[^ ]+)  Version: (.*)/) {
+            $ret{$section}{$file}{$2} = {
+                offset => hex($1),
+                ver => $3,
+            };
+        }
+    }
+
+    %ret
+}