From 05bdf4bfa9193e91532c52798a2ffc3fd8a3700c Mon Sep 17 00:00:00 2001 From: Yu Watanabe Date: Thu, 9 Jul 2026 11:17:56 +0900 Subject: [PATCH] compress: split compress_blob() and friends to minimize dlopen dependencies Previously, even though sd-journal does not support bzip2 and gzip compression, the dlopen ELF notes for those libraries were still being attached to libsystemd.so and various journal-handling executables. This occurred because the unified compression/decompression interfaces handled all formats unconditionally, causing the compiler and linker to pull in all associated dlopen notes across the board. To resolve this, split these functions into generic and journal-specific variants (e.g., introducing compress_blob_journal() and decompress_blob_journal()). The journal-specific variants only handle formats actually supported by the journal (LZ4, XZ, and ZSTD). By updating sd-journal, journald, journalctl, and related utilities to use these new `_journal` interfaces and switching them to the narrower COMPRESS_JOURNAL_NOTE macro, we ensure that unnecessary dlopen notes (for bzip2 and gzip) are no longer embedded into these binaries. --- src/basic/compress.c | 66 ++++++++++++++++++++-- src/basic/compress.h | 15 +++++ src/basic/dlopen-note.h | 5 +- src/journal-remote/journal-gatewayd.c | 2 +- src/journal/bsod.c | 2 +- src/journal/journalctl.c | 2 +- src/journal/journald.c | 2 +- src/libsystemd/sd-journal/journal-file.c | 8 +-- src/libsystemd/sd-journal/journal-verify.c | 2 +- src/login/loginctl.c | 2 +- src/machine/machinectl.c | 2 +- src/network/networkctl.c | 2 +- 12 files changed, 91 insertions(+), 19 deletions(-) diff --git a/src/basic/compress.c b/src/basic/compress.c index 5936a13f8e..2bc11f48bc 100644 --- a/src/basic/compress.c +++ b/src/basic/compress.c @@ -254,6 +254,19 @@ Compression compression_from_filename(const char *filename) { return c; } +bool compression_supported_journal(Compression c) { + static const unsigned supported = + (1U << COMPRESSION_NONE) | + (1U << COMPRESSION_XZ) * HAVE_XZ | + (1U << COMPRESSION_LZ4) * HAVE_LZ4 | + (1U << COMPRESSION_ZSTD) * HAVE_ZSTD; + + assert(c >= 0); + assert(c < _COMPRESSION_MAX); + + return BIT_SET(supported, c); +} + bool compression_supported(Compression c) { static const unsigned supported = (1U << COMPRESSION_NONE) | @@ -639,7 +652,7 @@ static int compress_blob_bzip2( #endif } -int compress_blob( +int compress_blob_journal( Compression compression, const void *src, uint64_t src_size, void *dst, size_t dst_alloc_size, size_t *dst_size, int level) { @@ -651,12 +664,23 @@ int compress_blob( return compress_blob_lz4(src, src_size, dst, dst_alloc_size, dst_size, level); case COMPRESSION_ZSTD: return compress_blob_zstd(src, src_size, dst, dst_alloc_size, dst_size, level); + default: + return -EOPNOTSUPP; + } +} + +int compress_blob( + Compression compression, + const void *src, uint64_t src_size, + void *dst, size_t dst_alloc_size, size_t *dst_size, int level) { + + switch (compression) { case COMPRESSION_GZIP: return compress_blob_gzip(src, src_size, dst, dst_alloc_size, dst_size, level); case COMPRESSION_BZIP2: return compress_blob_bzip2(src, src_size, dst, dst_alloc_size, dst_size, level); default: - return -EOPNOTSUPP; + return compress_blob_journal(compression, src, src_size, dst, dst_alloc_size, dst_size, level); } } @@ -1033,7 +1057,7 @@ static int decompress_blob_bzip2( #endif } -int decompress_blob( +int decompress_blob_journal( Compression compression, const void *src, uint64_t src_size, @@ -1054,6 +1078,20 @@ int decompress_blob( return decompress_blob_zstd( src, src_size, dst, dst_size, dst_max); + default: + return -EPROTONOSUPPORT; + } +} + +int decompress_blob( + Compression compression, + const void *src, + uint64_t src_size, + void **dst, + size_t *dst_size, + size_t dst_max) { + + switch (compression) { case COMPRESSION_GZIP: return decompress_blob_gzip( src, src_size, @@ -1063,7 +1101,10 @@ int decompress_blob( src, src_size, dst, dst_size, dst_max); default: - return -EPROTONOSUPPORT; + return decompress_blob_journal( + compression, + src, src_size, + dst, dst_size, dst_max); } } @@ -1452,7 +1493,7 @@ static int decompress_startswith_bzip2( #endif } -int decompress_startswith( +int decompress_startswith_journal( Compression compression, const void *src, uint64_t src_size, void **buffer, @@ -1466,12 +1507,25 @@ int decompress_startswith( return decompress_startswith_lz4(src, src_size, buffer, prefix, prefix_len, extra); case COMPRESSION_ZSTD: return decompress_startswith_zstd(src, src_size, buffer, prefix, prefix_len, extra); + default: + return -EOPNOTSUPP; + } +} + +int decompress_startswith( + Compression compression, + const void *src, uint64_t src_size, + void **buffer, + const void *prefix, size_t prefix_len, + uint8_t extra) { + + switch (compression) { case COMPRESSION_GZIP: return decompress_startswith_gzip(src, src_size, buffer, prefix, prefix_len, extra); case COMPRESSION_BZIP2: return decompress_startswith_bzip2(src, src_size, buffer, prefix, prefix_len, extra); default: - return -EOPNOTSUPP; + return decompress_startswith_journal(compression, src, src_size, buffer, prefix, prefix_len, extra); } } diff --git a/src/basic/compress.h b/src/basic/compress.h index 52fdf3aa27..e25ab6d9a4 100644 --- a/src/basic/compress.h +++ b/src/basic/compress.h @@ -27,6 +27,7 @@ Compression compression_from_string_harder(const char *s); * filename does not carry a recognized compression suffix. */ Compression compression_from_filename(const char *filename); +bool compression_supported_journal(Compression c); bool compression_supported(Compression c); /* Buffer size used by streaming compression APIs and pipeline stages that feed into them. Sized to @@ -59,9 +60,17 @@ Compression compressor_type(const Compressor *c); /* Blob compression/decompression */ +int compress_blob_journal( + Compression compression, + const void *src, uint64_t src_size, + void *dst, size_t dst_alloc_size, size_t *dst_size, int level); int compress_blob(Compression compression, const void *src, uint64_t src_size, void *dst, size_t dst_alloc_size, size_t *dst_size, int level); +int decompress_blob_journal( + Compression compression, + const void *src, uint64_t src_size, + void **dst, size_t *dst_size, size_t dst_max); int decompress_blob(Compression compression, const void *src, uint64_t src_size, void **dst, size_t *dst_size, size_t dst_max); @@ -69,6 +78,12 @@ int decompress_blob(Compression compression, int decompress_zlib_raw(const void *src, uint64_t src_size, void *dst, size_t dst_size, int wbits); +int decompress_startswith_journal( + Compression compression, + const void *src, uint64_t src_size, + void **buffer, + const void *prefix, size_t prefix_len, + uint8_t extra); int decompress_startswith(Compression compression, const void *src, uint64_t src_size, void **buffer, diff --git a/src/basic/dlopen-note.h b/src/basic/dlopen-note.h index 41661939a1..6d3bd5e2bc 100644 --- a/src/basic/dlopen-note.h +++ b/src/basic/dlopen-note.h @@ -94,8 +94,11 @@ LIBZSTD_NOTE(priority) #define COMPRESS_DEFAULT_NOTE \ + COMPRESS_JOURNAL_NOTE; \ LIBBZ2_NOTE(suggested); \ + LIBZ_NOTE(suggested) + +#define COMPRESS_JOURNAL_NOTE \ LIBLZ4_NOTE(COMPRESSION_PRIORITY_LZ4); \ LIBLZMA_NOTE(COMPRESSION_PRIORITY_XZ); \ - LIBZ_NOTE(suggested); \ LIBZSTD_NOTE(COMPRESSION_PRIORITY_ZSTD) diff --git a/src/journal-remote/journal-gatewayd.c b/src/journal-remote/journal-gatewayd.c index 9def4a3bc9..8a6e59c8d7 100644 --- a/src/journal-remote/journal-gatewayd.c +++ b/src/journal-remote/journal-gatewayd.c @@ -1259,7 +1259,7 @@ static int run(int argc, char *argv[]) { MHD_USE_THREAD_PER_CONNECTION; int r, n; - COMPRESS_DEFAULT_NOTE; + COMPRESS_JOURNAL_NOTE; LIBGNUTLS_NOTE(suggested); log_setup(); diff --git a/src/journal/bsod.c b/src/journal/bsod.c index 9a9067088c..78093844fa 100644 --- a/src/journal/bsod.c +++ b/src/journal/bsod.c @@ -288,7 +288,7 @@ static int run(int argc, char *argv[]) { _cleanup_free_ char *message = NULL; int r; - COMPRESS_DEFAULT_NOTE; + COMPRESS_JOURNAL_NOTE; LIBQRENCODE_NOTE(suggested); log_setup(); diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c index bb5b376a93..b407a77d97 100644 --- a/src/journal/journalctl.c +++ b/src/journal/journalctl.c @@ -1022,7 +1022,7 @@ static int run(int argc, char *argv[]) { _cleanup_strv_free_ char **args = NULL; int r; - COMPRESS_DEFAULT_NOTE; + COMPRESS_JOURNAL_NOTE; LIBACL_NOTE(recommended); LIBBLKID_NOTE(recommended); LIBCRYPTSETUP_NOTE(suggested); diff --git a/src/journal/journald.c b/src/journal/journald.c index 3cab48f6b7..ec095684df 100644 --- a/src/journal/journald.c +++ b/src/journal/journald.c @@ -26,7 +26,7 @@ static int run(int argc, char *argv[]) { LogTarget log_target; int r; - COMPRESS_DEFAULT_NOTE; + COMPRESS_JOURNAL_NOTE; LIBACL_NOTE(recommended); LIBCRYPTO_NOTE(suggested); LIBPCRE2_NOTE(suggested); diff --git a/src/libsystemd/sd-journal/journal-file.c b/src/libsystemd/sd-journal/journal-file.c index 93b2c90c15..b0df06d75a 100644 --- a/src/libsystemd/sd-journal/journal-file.c +++ b/src/libsystemd/sd-journal/journal-file.c @@ -365,7 +365,7 @@ static Compression getenv_compression(void) { return DEFAULT_COMPRESSION; } - if (!compression_supported(c)) { + if (!compression_supported_journal(c)) { log_debug("Unsupported compression algorithm specified, ignoring: %s", e); return DEFAULT_COMPRESSION; } @@ -1861,7 +1861,7 @@ static int maybe_compress_payload( return 0; } - r = compress_blob(c, src, size, dst, size - 1, rsize, /* level= */ -1); + r = compress_blob_journal(c, src, size, dst, size - 1, rsize, /* level= */ -1); if (r < 0) return log_debug_errno(r, "Failed to compress data object using %s, ignoring: %m", compression_to_string(c)); @@ -1983,7 +1983,7 @@ static int maybe_decompress_payload( int r; if (field) { - r = decompress_startswith(compression, payload, size, &f->compress_buffer, field, + r = decompress_startswith_journal(compression, payload, size, &f->compress_buffer, field, field_length, '='); if (r < 0) return log_debug_errno(r, @@ -2003,7 +2003,7 @@ static int maybe_decompress_payload( return 1; } - r = decompress_blob(compression, payload, size, &f->compress_buffer, &rsize, DATA_SIZE_MAX); + r = decompress_blob_journal(compression, payload, size, &f->compress_buffer, &rsize, DATA_SIZE_MAX); if (r < 0) return r; diff --git a/src/libsystemd/sd-journal/journal-verify.c b/src/libsystemd/sd-journal/journal-verify.c index d214a68e68..79061940b3 100644 --- a/src/libsystemd/sd-journal/journal-verify.c +++ b/src/libsystemd/sd-journal/journal-verify.c @@ -125,7 +125,7 @@ static int hash_payload(JournalFile *f, Object *o, uint64_t offset, const uint8_ _cleanup_free_ void *b = NULL; size_t b_size; - r = decompress_blob(c, src, size, &b, &b_size, DATA_SIZE_MAX); + r = decompress_blob_journal(c, src, size, &b, &b_size, DATA_SIZE_MAX); if (r < 0) { error_errno(offset, r, "%s decompression failed: %m", compression_to_string(c)); diff --git a/src/login/loginctl.c b/src/login/loginctl.c index be67025421..566f4db877 100644 --- a/src/login/loginctl.c +++ b/src/login/loginctl.c @@ -1662,7 +1662,7 @@ static int run(int argc, char *argv[]) { char **args = NULL; int r; - COMPRESS_DEFAULT_NOTE; + COMPRESS_JOURNAL_NOTE; setlocale(LC_ALL, ""); log_setup(); diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c index dc2381fc84..19ad385733 100644 --- a/src/machine/machinectl.c +++ b/src/machine/machinectl.c @@ -2635,7 +2635,7 @@ static int run(int argc, char *argv[]) { _cleanup_strv_free_ char **args = NULL; int r; - COMPRESS_DEFAULT_NOTE; + COMPRESS_JOURNAL_NOTE; LIBSELINUX_NOTE(recommended); setlocale(LC_ALL, ""); diff --git a/src/network/networkctl.c b/src/network/networkctl.c index f85c74b6af..f7a6e6eef7 100644 --- a/src/network/networkctl.c +++ b/src/network/networkctl.c @@ -209,7 +209,7 @@ static int run(int argc, char* argv[]) { char **args = NULL; int r; - COMPRESS_DEFAULT_NOTE; + COMPRESS_JOURNAL_NOTE; LIBSELINUX_NOTE(recommended); log_setup();