src: rework mem_clear()

src/compress/compress.cpp

@@ -83,7 +83,7 @@ int upx_compress(const upx_bytep src, unsigned src_len, upx_bytep dst, unsigned
 
     if (!cresult)
         cresult = &cresult_buffer;
-    memset(cresult, 0, sizeof(*cresult));
+    cresult->reset();
 #if 1
     // debugging aid
     cresult->debug.method = method;

src/compress/compress_lzma.cpp

@@ -433,7 +433,7 @@ int upx_lzma_decompress(const upx_bytep src, unsigned src_len, upx_bytep dst, un
     COMPILE_TIME_ASSERT(LZMA_LIT_SIZE == 768)
 
     CLzmaDecoderState s;
-    memset(&s, 0, sizeof(s));
+    mem_clear(&s);
     SizeT src_out = 0, dst_out = 0;
     int r = UPX_E_ERROR;
     int rh;

src/compress/compress_zlib.cpp

@@ -31,8 +31,7 @@
 #include <zlib/deflate.h>
 
 void zlib_compress_config_t::reset() noexcept {
-    mem_clear(this, sizeof(*this));
-
+    mem_clear(this);
     mem_level.reset();
     window_bits.reset();
     strategy.reset();

src/compress/compress_zstd.cpp

@@ -26,7 +26,7 @@
 
 #include "../conf.h"
 
-void zstd_compress_config_t::reset() noexcept { mem_clear(this, sizeof(*this)); }
+void zstd_compress_config_t::reset() noexcept { mem_clear(this); }
 
 #if WITH_ZSTD
 #include "compress.h"

src/conf.h

@@ -380,6 +380,18 @@ struct UnsignedSizeOf {
 #define usizeof(expr)   (UnsignedSizeOf<sizeof(expr)>::value)
 ACC_COMPILE_TIME_ASSERT_HEADER(usizeof(int) == sizeof(int))
 
+template <class T>
+inline void mem_clear(T *object) noexcept {
+    static_assert(std::is_class_v<T>);
+    static_assert(std::is_standard_layout_v<T>);
+    static_assert(std::is_trivially_copyable_v<T>);
+    static constexpr size_t size = sizeof(*object);
+    static_assert(size >= 1 && size <= UPX_RSIZE_MAX_MEM);
+    memset((void *) object, 0, size);
+}
+template <class T, size_t N>
+inline void mem_clear(T (&array)[N]) noexcept = delete;
+
 // An Array allocates memory on the heap, and automatically
 // gets destructed when leaving scope or on exceptions.
 #define Array(type, var, n) \
@@ -582,12 +594,11 @@ typedef upx_callback_t *upx_callback_p;
 typedef void (__acc_cdecl *upx_progress_func_t)
     (upx_callback_p, unsigned, unsigned);
 
-struct upx_callback_t
-{
+struct upx_callback_t {
     upx_progress_func_t nprogress;
     void *user;
 
-    void reset() noexcept { memset(this, 0, sizeof(*this)); }
+    void reset() noexcept { mem_clear(this); }
 };
 
 
@@ -640,8 +651,7 @@ inline void oassign(T &v, const OptVar<T,a,b,c> &other) {
 }
 
 
-struct lzma_compress_config_t
-{
+struct lzma_compress_config_t {
     typedef OptVar<unsigned,  2u, 0u,   4u> pos_bits_t;             // pb
     typedef OptVar<unsigned,  0u, 0u,   4u> lit_pos_bits_t;         // lp
     typedef OptVar<unsigned,  3u, 0u,   8u> lit_context_bits_t;     // lc
@@ -661,13 +671,11 @@ struct lzma_compress_config_t
     void reset() noexcept;
 };
 
-struct ucl_compress_config_t : public REAL_ucl_compress_config_t
-{
+struct ucl_compress_config_t : public REAL_ucl_compress_config_t {
     void reset() noexcept { memset(this, 0xff, sizeof(*this)); }
 };
 
-struct zlib_compress_config_t
-{
+struct zlib_compress_config_t {
     typedef OptVar<unsigned,  8u, 1u,   9u> mem_level_t;            // ml
     typedef OptVar<unsigned, 15u, 9u,  15u> window_bits_t;          // wb
     typedef OptVar<unsigned,  0u, 0u,   4u> strategy_t;             // st
@@ -679,19 +687,18 @@ struct zlib_compress_config_t
     void reset() noexcept;
 };
 
-struct zstd_compress_config_t
-{
+struct zstd_compress_config_t {
     unsigned dummy;
 
     void reset() noexcept;
 };
 
-struct upx_compress_config_t
-{
+struct upx_compress_config_t {
     lzma_compress_config_t  conf_lzma;
     ucl_compress_config_t   conf_ucl;
     zlib_compress_config_t  conf_zlib;
     zstd_compress_config_t  conf_zstd;
+
     void reset() noexcept { conf_lzma.reset(); conf_ucl.reset(); conf_zlib.reset(); conf_zstd.reset(); }
 };
 
@@ -702,8 +709,7 @@ struct upx_compress_config_t
 // compression - result_t
 **************************************************************************/
 
-struct lzma_compress_result_t
-{
+struct lzma_compress_result_t {
     unsigned pos_bits;              // pb
     unsigned lit_pos_bits;          // lp
     unsigned lit_context_bits;      // lc
@@ -713,37 +719,35 @@ struct lzma_compress_result_t
     unsigned match_finder_cycles;
     unsigned num_probs;             // (computed result)
 
-    void reset() noexcept { memset(this, 0, sizeof(*this)); }
+    void reset() noexcept { mem_clear(this); }
 };
 
-struct ucl_compress_result_t
-{
+struct ucl_compress_result_t {
     ucl_uint result[16];
 
-    void reset() noexcept { memset(this, 0, sizeof(*this)); }
+    void reset() noexcept { mem_clear(this); }
 };
 
-struct zlib_compress_result_t
-{
+struct zlib_compress_result_t {
     unsigned dummy;
 
-    void reset() noexcept { memset(this, 0, sizeof(*this)); }
+    void reset() noexcept { mem_clear(this); }
 };
 
-struct zstd_compress_result_t
-{
+struct zstd_compress_result_t {
     unsigned dummy;
 
-    void reset() noexcept { memset(this, 0, sizeof(*this)); }
+    void reset() noexcept { mem_clear(this); }
 };
 
-struct upx_compress_result_t
-{
+struct upx_compress_result_t {
     // debugging aid
-    struct {
+    struct Debug {
         int method, level;
         unsigned u_len, c_len;
-    } debug;
+        void reset() noexcept { mem_clear(this); }
+    };
+    Debug debug;
 
     lzma_compress_result_t  result_lzma;
     ucl_compress_result_t   result_ucl;
@@ -751,7 +755,7 @@ struct upx_compress_result_t
     zstd_compress_result_t  result_zstd;
 
     void reset() noexcept {
-        memset(&this->debug, 0, sizeof(this->debug));
+        debug.reset();
         result_lzma.reset(); result_ucl.reset(); result_zlib.reset(); result_zstd.reset();
     }
 };

src/lefile.cpp

@@ -34,8 +34,8 @@ LeFile::LeFile(InputFile *f) : fif(f), fof(nullptr), le_offset(0), exe_offset(0)
     COMPILE_TIME_ASSERT(sizeof(le_header_t) == 196)
     COMPILE_TIME_ASSERT(sizeof(le_object_table_entry_t) == 24)
     COMPILE_TIME_ASSERT(sizeof(le_pagemap_entry_t) == 4)
-    memset(&ih, 0, sizeof ih);
-    memset(&oh, 0, sizeof oh);
+    mem_clear(&ih);
+    mem_clear(&oh);
 }
 
 LeFile::~LeFile() {
@@ -257,7 +257,7 @@ void LeFile::writeFile(OutputFile *f, bool le) {
 
 void LeFile::countFixups(unsigned *counts) const {
     const unsigned o = objects;
-    memset(counts, 0, sizeof(unsigned) * (o + 2));
+    memset(counts, 0, mem_size(sizeof(unsigned), o + 2));
     // counts[0..objects-1] - # of 32-bit offset relocations in for that objects
     // counts[objects]      - # of selector fixups
     // counts[objects+1]    - # of self-relative fixups

src/options.cpp

@@ -40,7 +40,7 @@ std::mutex opt_lock_mutex;
 
 void Options::reset() noexcept {
     Options *const o = this;
-    mem_clear(o, sizeof(*o));
+    mem_clear(o);
     o->crp.reset();
 
     o->cmd = CMD_NONE;

src/p_exe.cpp

@@ -72,7 +72,7 @@ int PackExe::fillExeHeader(struct exe_header_t *eh) const {
     if (ih.relocs == 0)
         flag |= NORELOC;
 
-    memset(&oh, 0, sizeof(oh));
+    mem_clear(&oh);
     oh.ident = 'M' + 'Z' * 256;
     oh.headsize16 = 2;
 
@@ -656,7 +656,7 @@ void PackExe::unpack(OutputFile *fo) {
     }
 
     // fill new exe header
-    memset(&oh, 0, sizeof(oh));
+    mem_clear(&oh);
     oh.ident = 'M' + 'Z' * 256;
 
     if (relocnum) {

src/p_wcle.cpp

@@ -174,8 +174,9 @@ void PackWcle::readObjectTable() {
 void PackWcle::encodeObjectTable() {
     unsigned ic, jc;
 
-    oobject_table = New(le_object_table_entry_t, soobject_table = 2);
-    memset(oobject_table, 0, soobject_table * sizeof(*oobject_table));
+    soobject_table = 2;
+    oobject_table = New(le_object_table_entry_t, soobject_table);
+    memset(oobject_table, 0, mem_size(sizeof(*oobject_table), soobject_table));
 
     // object #1:
     OOT(0, base_address) = IOT(0, base_address);

src/packer.cpp

@@ -43,7 +43,7 @@ Packer::Packer(InputFile *f)
         file_size = fi->st_size();
     mem_size_assert(1, file_size_u);
     uip = new UiPacker(this);
-    mem_clear(&ph, sizeof(ph));
+    mem_clear(&ph);
 }
 
 Packer::~Packer() noexcept {
@@ -599,7 +599,7 @@ unsigned Packer::getRandomId() const {
 
 // this is called directly after the constructor from class PackMaster
 void Packer::initPackHeader() {
-    mem_clear(&ph, sizeof(ph));
+    mem_clear(&ph);
     ph.version = getVersion();
     ph.format = getFormat();
     ph.method = M_NONE;

src/pefile.cpp

@@ -1067,7 +1067,7 @@ PeFile::Export::Export(char *_base) : base(_base), iv(_base) {
     COMPILE_TIME_ASSERT_ALIGNED1(export_dir_t)
     ename = functionptrs = ordinals = nullptr;
     names = nullptr;
-    memset(&edir, 0, sizeof(edir));
+    mem_clear(&edir);
     size = 0;
 }
 

src/ui.cpp

@@ -162,7 +162,7 @@ UiPacker::UiPacker(const Packer *p_) : ui_pass(0), ui_total_passes(0), p(p_), s(
     cb.reset();
 
     s = new State;
-    memset(s, 0, sizeof(*s));
+    mem_clear(s);
     s->msg_buf[0] = '\r';
 
 #if defined(UI_USE_SCREEN)

src/util/membuffer.h

@@ -185,7 +185,7 @@ private:
         void *last_return_address_dealloc;
         void *last_return_address_fill;
         void *last_return_address_subref;
-        Debug() noexcept { memset(this, 0, sizeof(*this)); }
+        Debug() noexcept { mem_clear(this); }
     };
     Debug debug;
 #endif

src/util/util.h

@@ -66,12 +66,6 @@ inline void mem_size_assert(upx_uint64_t element_size, upx_uint64_t n) {
     (void) mem_size(element_size, n); // assert size
 }
 
-// will throw on invalid size
-inline void mem_clear(void *p, size_t n) {
-    (void) mem_size(1, n); // assert size
-    memset(p, 0, n);
-}
-
 // "new" with asserted size; will throw on invalid size
 #if DEBUG
 template <class T>

src/work.cpp

@@ -61,7 +61,7 @@
 void do_one_file(const char *iname, char *oname) {
     int r;
     struct stat st;
-    memset(&st, 0, sizeof(st));
+    mem_clear(&st);
 #if (HAVE_LSTAT)
     r = lstat(iname, &st);
 #else
@@ -106,7 +106,7 @@ void do_one_file(const char *iname, char *oname) {
 
 #if (USE_FTIME)
     struct ftime fi_ftime;
-    memset(&fi_ftime, 0, sizeof(fi_ftime));
+    mem_clear(&fi_ftime);
     if (opt->preserve_timestamp) {
         if (getftime(fi.getFd(), &fi_ftime) != 0)
             throwIOException("cannot determine file timestamp");