[Qemu-devel] [RISU PATCH v6 08/10] risu: add support compressed tracefiles

["Alex Bennée" <alex.bennee@linaro.org>]

This uses the magic of zlib's gzread/write interface to wrap the
tracefile in compression. The code changes are tiny. I spent more time
messing about with the configure/linker stuff to auto-detect bits.

As you need decent multi-arch support or a correctly setup cross
toolchain we fall back if we can't compile with zlib. This
unfortunately needs some #ifdef hackery around the zlib bits in
risu.c.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
--
v5
  - re-base
  - also don't use zlib if using stdio fds
v4
  - removed redundant config.h output, added HAVE_ZLIB
  - added BUILD_INC to deal with out-of-tree builds
---
 Makefile  |  4 ++--
 configure | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 risu.c    | 48 ++++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 101 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index 9a29bb4..ca80eef 100644
--- a/Makefile
+++ b/Makefile
@@ -17,7 +17,7 @@ VPATH=$(SRCDIR)
 
 CFLAGS ?= -g
 
-ALL_CFLAGS = -Wall -D_GNU_SOURCE -DARCH=$(ARCH) $(CFLAGS) $(EXTRA_CFLAGS)
+ALL_CFLAGS = -Wall -D_GNU_SOURCE -DARCH=$(ARCH) $(BUILD_INC) $(CFLAGS) $(EXTRA_CFLAGS)
 
 PROG=risu
 SRCS=risu.c comms.c reginfo.c risu_$(ARCH).c risu_reginfo_$(ARCH).c
@@ -35,7 +35,7 @@ all: $(PROG) $(BINS)
 dump: $(RISU_ASMS)
 
 $(PROG): $(OBJS)
-	$(CC) $(STATIC) $(ALL_CFLAGS) -o $@ $^
+	$(CC) $(STATIC) $(ALL_CFLAGS) -o $@ $^ $(LDFLAGS)
 
 %.risu.asm: %.risu.bin
 	${OBJDUMP} -b binary -m $(ARCH) -D $^ > $@
diff --git a/configure b/configure
index c4b5adb..1dc527b 100755
--- a/configure
+++ b/configure
@@ -32,6 +32,10 @@ compile() {
     $CC $CFLAGS -c -o ${1}.o ${1}.c 2>/dev/null
 }
 
+link() {
+    $LD $LDFLAGS -l${2} -o ${1} ${1}.o 2>/dev/null
+}
+
 check_define() {
     c=${tmp_dir}/check_define_${1}
     cat > ${c}.c <<EOF
@@ -58,6 +62,48 @@ guess_arch() {
     fi
 }
 
+check_type() {
+    c=${tmp_dir}/check_type_${1}
+    cat > ${c}.c <<EOF
+#include <inttypes.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+int main(void) { $1 thisone; return 0; }
+EOF
+    compile $c
+}
+
+check_lib() {
+    c=${tmp_dir}/check_lib${1}
+    cat > ${c}.c <<EOF
+#include <stdint.h>
+#include <$2.h>
+
+int main(void) { $3; return 0; }
+EOF
+    compile $c && link $c $1
+}
+
+generate_config() {
+    cfg=config.h
+    echo "generating config.h..."
+
+    echo "/* config.h - generated by the 'configure' script */" > $cfg
+    echo "#ifndef CONFIG_H" >> $cfg
+    echo "#define CONFIG_H 1" >> $cfg
+
+    if check_lib z zlib "zlibVersion()"; then
+        echo "#define HAVE_ZLIB 1" >> $cfg
+        LDFLAGS=-lz
+    fi
+
+    echo "#endif /* CONFIG_H */" >> $cfg
+
+    echo "...done"
+}
+
 generate_makefilein() {
     m=Makefile.in
     echo "generating Makefile.in..."
@@ -65,11 +111,13 @@ generate_makefilein() {
     echo "# Makefile.in - generated by the 'configure' script" > $m
     echo "ARCH:=${ARCH}" >> $m
     echo "CC:=${CC}" >> $m
+    echo "LDFLAGS:=${LDFLAGS}" >> $m
     echo "AS:=${AS}" >> $m
     echo "OBJCOPY:=${OBJCOPY}" >> $m
     echo "OBJDUMP:=${OBJDUMP}" >> $m
     echo "STATIC:=${STATIC}" >> $m
     echo "SRCDIR:=${SRCDIR}" >> $m
+    echo "BUILD_INC:=${BUILD_INC}" >> $m
 
     echo "...done"
 }
@@ -118,6 +166,7 @@ done
 
 CC="${CC-${CROSS_PREFIX}gcc}"
 AS="${AS-${CROSS_PREFIX}as}"
+LD="${LD-${CROSS_PREFIX}ld}"
 OBJCOPY="${OBJCOPY-${CROSS_PREFIX}objcopy}"
 OBJDUMP="${OBJDUMP-${CROSS_PREFIX}objdump}"
 
@@ -125,15 +174,17 @@ if test "x${ARCH}" = "x"; then
     guess_arch
 fi
 
-generate_makefilein
-
 # Are we in a separate build tree? If so, link the Makefile
 # so that 'make' works.
 if test ! -e Makefile; then
     echo "linking Makefile..."
+    BUILD_INC="-I $(pwd)"
     ln -s "${SRCDIR}/Makefile" .
 fi
 
+generate_config
+generate_makefilein
+
 rm -r "$tmp_dir"
 
 echo "type 'make' to start the build"
diff --git a/risu.c b/risu.c
index 476475c..47e50ad 100644
--- a/risu.c
+++ b/risu.c
@@ -26,6 +26,8 @@
 #include <fcntl.h>
 #include <string.h>
 
+#include "config.h"
+
 #include "risu.h"
 
 void *memblock;
@@ -34,6 +36,11 @@ int apprentice_fd, master_fd;
 int trace;
 size_t signal_count;
 
+#ifdef HAVE_ZLIB
+#include <zlib.h>
+gzFile gz_trace_file;
+#endif
+
 sigjmp_buf jmpbuf;
 
 /* Should we test for FP exception status bits? */
@@ -48,7 +55,17 @@ int read_sock(void *ptr, size_t bytes)
 
 int write_trace(void *ptr, size_t bytes)
 {
-    size_t res = write(master_fd, ptr, bytes);
+    size_t res;
+
+#ifdef HAVE_ZLIB
+    if (master_fd == STDOUT_FILENO) {
+#endif
+        res = write(master_fd, ptr, bytes);
+#ifdef HAVE_ZLIB
+    } else {
+        res = gzwrite(gz_trace_file, ptr, bytes);
+    }
+#endif
     return (res == bytes) ? 0 : 1;
 }
 
@@ -66,7 +83,18 @@ int write_sock(void *ptr, size_t bytes)
 
 int read_trace(void *ptr, size_t bytes)
 {
-    size_t res = read(apprentice_fd, ptr, bytes);
+    size_t res;
+
+#ifdef HAVE_ZLIB
+    if (apprentice_fd == STDIN_FILENO) {
+#endif
+        res = read(apprentice_fd, ptr, bytes);
+#ifdef HAVE_ZLIB
+    } else {
+        res = gzread(gz_trace_file, ptr, bytes);
+    }
+#endif
+
     return (res == bytes) ? 0 : 1;
 }
 
@@ -189,6 +217,11 @@ void load_image(const char *imgfile)
 int master(void)
 {
     if (sigsetjmp(jmpbuf, 1)) {
+#ifdef HAVE_ZLIB
+        if (trace && master_fd != STDOUT_FILENO) {
+            gzclose(gz_trace_file);
+        }
+#endif
         close(master_fd);
         if (trace) {
             fprintf(stderr, "trace complete after %zd checkpoints\n", signal_count);
@@ -209,6 +242,11 @@ int master(void)
 int apprentice(void)
 {
     if (sigsetjmp(jmpbuf, 1)) {
+#ifdef HAVE_ZLIB
+        if (trace && apprentice_fd != STDIN_FILENO) {
+            gzclose(gz_trace_file);
+        }
+#endif
         close(apprentice_fd);
         fprintf(stderr, "finished early after %zd checkpoints\n", signal_count);
         return report_match_status();
@@ -316,6 +354,9 @@ int main(int argc, char **argv)
                 master_fd = STDOUT_FILENO;
             } else {
                 master_fd = open(trace_fn, O_WRONLY|O_CREAT, S_IRWXU);
+#ifdef HAVE_ZLIB
+                gz_trace_file = gzdopen(master_fd, "wb9");
+#endif
             }
         } else {
             fprintf(stderr, "master port %d\n", port);
@@ -328,6 +369,9 @@ int main(int argc, char **argv)
                 apprentice_fd = STDIN_FILENO;
             } else {
                 apprentice_fd = open(trace_fn, O_RDONLY);
+#ifdef HAVE_ZLIB
+                gz_trace_file = gzdopen(apprentice_fd, "rb");
+#endif
             }
         } else {
             fprintf(stderr, "apprentice host %s port %d\n", hostname, port);
-- 
2.13.0