From a64af8c9b6598f6d2685227f64f5ccb9b48c663c Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Mon, 10 May 2021 10:31:41 +0200 Subject: [PATCH] scripts/versions.awk: Add strings and hashes to This generates new macros of this from: They are useful for symbol lookups using _dl_lookup_direct. Tested-by: Carlos O'Donell Reviewed-by: Carlos O'Donell --- scripts/versions.awk | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/scripts/versions.awk b/scripts/versions.awk index d56f4e7..3291123 100644 --- a/scripts/versions.awk +++ b/scripts/versions.awk @@ -32,6 +32,29 @@ BEGIN { sort = "sort -t. -k 1,1 -k 2n,2n -k 3 > " tmpfile; } +# GNU awk does not implement the ord and chr functions. +# +# says that they are "written very nicely", using code similar to what +# is included here. +function chr(c) { + return sprintf("%c", c) +} + +BEGIN { + for (c = 1; c < 127; c++) { + ord_table[chr(c)] = c; + } +} + +function ord(c) { + if (ord_table[c]) { + return ord_table[c]; + } else { + printf("Invalid character reference: '%c'\n", c) > "/dev/stderr"; + ++lossage; + } +} + # Remove comment lines. /^ *#/ { next; @@ -90,6 +113,17 @@ function close_and_move(name, real_name) { system(move_if_change " " name " " real_name " >&2"); } +# ELF hash, for use with symbol versions. +function elf_hash(s, i, acc) { + acc = 0; + for (i = 1; i <= length(s); ++i) { + acc = and(lshift(acc, 4) + ord(substr(s, i, 1)), 0xffffffff); + top = and(acc, 0xf0000000); + acc = and(xor(acc, rshift(top, 24)), compl(top)); + } + return acc; +} + # Now print the accumulated information. END { close(sort); @@ -145,6 +179,8 @@ END { && oldver ~ "^GLIBC_[0-9]" \ && sym ~ "^[A-Za-z0-9_]*$") { ver_val = oldver; + printf("#define %s_STRING \"%s\"\n", first_ver_macro, ver_val) > first_ver_header; + printf("#define %s_HASH 0x%x\n", first_ver_macro, elf_hash(ver_val)) > first_ver_header; gsub("\\.", "_", ver_val); printf("#define %s %s\n", first_ver_macro, ver_val) > first_ver_header; first_ver_seen[first_ver_macro] = 1; -- 2.7.4