gcov: Add small utility to deal with test coverage information from Xen

Currently the utility can read and reset coverage informations.

Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>

.gitignore

@@ -229,6 +229,7 @@ tools/misc/gtraceview
 tools/misc/gtracestat
 tools/misc/xenlockprof
 tools/misc/lowmemd
+tools/misc/xencov
 tools/pygrub/build/*
 tools/python/build/*
 tools/python/xen/util/path.py

.hgignore

@@ -224,6 +224,7 @@
 ^tools/misc/gtraceview$
 ^tools/misc/gtracestat$
 ^tools/misc/xenlockprof$
+^tools/misc/xencov$
 ^tools/pygrub/build/.*$
 ^tools/python/build/.*$
 ^tools/python/xen/util/path\.py$

tools/misc/Makefile

@@ -9,7 +9,7 @@ CFLAGS += $(CFLAGS_libxenstore)
 
 HDRS     = $(wildcard *.h)
 
-TARGETS-y := xenperf xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd
+TARGETS-y := xenperf xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd xencov
 TARGETS-$(CONFIG_X86) += xen-detect xen-hvmctx xen-hvmcrash xen-lowmemd
 TARGETS-$(CONFIG_MIGRATE) += xen-hptool
 TARGETS := $(TARGETS-y)
@@ -22,7 +22,8 @@ INSTALL_BIN-y := xencons
 INSTALL_BIN-$(CONFIG_X86) += xen-detect
 INSTALL_BIN := $(INSTALL_BIN-y)
 
-INSTALL_SBIN-y := xm xen-bugtool xen-python-path xend xenperf xsview xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd xen-ringwatch
+INSTALL_SBIN-y := xm xen-bugtool xen-python-path xend xenperf xsview xenpm xen-tmem-list-parse gtraceview \
+	gtracestat xenlockprof xenwatchdogd xen-ringwatch xencov
 INSTALL_SBIN-$(CONFIG_X86) += xen-hvmctx xen-hvmcrash xen-lowmemd
 INSTALL_SBIN-$(CONFIG_MIGRATE) += xen-hptool
 INSTALL_SBIN := $(INSTALL_SBIN-y)
@@ -85,4 +86,7 @@ xen-lowmemd: xen-lowmemd.o
 gtraceview: gtraceview.o
 	$(CC) $(LDFLAGS) -o $@ $< $(CURSES_LIBS) $(APPEND_LDFLAGS)
 
+xencov: xencov.o
+	$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
+
 -include $(DEPS)

tools/misc/xencov.c

@@ -0,0 +1,152 @@
+/*
+ * xencov: handle test coverage information from Xen.
+ *
+ * Copyright (c) 2013, Citrix Systems R&D Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <xenctrl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <err.h>
+#include <sys/mman.h>
+
+static xc_interface *gcov_xch = NULL;
+
+static void gcov_init(void)
+{
+    gcov_xch = xc_interface_open(NULL, NULL, 0);
+    if ( !gcov_xch )
+        err(1, "opening interface");
+}
+
+int gcov_get_info(int op, struct xen_sysctl *sys, void *ptr)
+{
+    struct xen_sysctl_coverage_op *cov;
+
+    memset(sys, 0, sizeof(*sys));
+    sys->cmd = XEN_SYSCTL_coverage_op;
+
+    cov = &sys->u.coverage_op;
+    cov->cmd = op;
+    cov->u.raw_info.p = ptr;
+
+    return xc_sysctl(gcov_xch, sys);
+}
+
+static void gcov_read(const char *fn, int reset)
+{
+    struct xen_sysctl sys;
+    unsigned page_size = sysconf(_SC_PAGESIZE);
+    uint32_t total_len;
+    uint8_t *p;
+    size_t size;
+    FILE *f;
+    int op = reset ? XEN_SYSCTL_COVERAGE_read_and_reset :
+                     XEN_SYSCTL_COVERAGE_read;
+
+    /* get total length */
+    if ( gcov_get_info(XEN_SYSCTL_COVERAGE_get_total_size, &sys, NULL) < 0 )
+        err(1, "getting total length");
+    total_len = sys.u.coverage_op.u.total_size;
+    fprintf(stderr, "returned %u bytes\n", (unsigned) total_len);
+
+    /* safe check */
+    if ( total_len > 16u * 1024u * 1024u )
+        errx(1, "coverage size too big %u bytes\n", total_len);
+
+    /* allocate */
+    size = total_len + page_size;
+    size -= (size % page_size);
+    p = mmap(0, size, PROT_WRITE|PROT_READ,
+             MAP_PRIVATE|MAP_ANON|MAP_LOCKED, -1, 0);
+    if ( p == (uint8_t *) -1 )
+        err(1, "mapping memory for coverage");
+
+    /* get data */
+    memset(p, 0, total_len);
+    if ( gcov_get_info(op, &sys, p) < 0 )
+        err(1, "getting coverage information");
+
+    /* write to a file */
+    if ( strcmp(fn, "-") == 0 )
+        f = stdout;
+    else
+        f = fopen(fn, "w");
+    if ( !f )
+        err(1, "opening output file");
+    if ( fwrite(p, 1, total_len, f) != total_len )
+        err(1, "writing coverage to file");
+    if (f != stdout)
+        fclose(f);
+}
+
+static void gcov_reset(void)
+{
+    struct xen_sysctl sys;
+
+    if ( gcov_get_info(XEN_SYSCTL_COVERAGE_reset, &sys, NULL) < 0 )
+        err(1, "resetting coverage information");
+}
+
+static void usage(int exit_code)
+{
+    FILE *out = exit_code ? stderr : stdout;
+
+    fprintf(out, "xencov {reset|read|read-reset} [<filename>]\n"
+        "\treset       reset information\n"
+        "\tread        read information from xen to filename\n"
+        "\tread-reset  read and reset information from xen to filename\n"
+        "\tfilename  optional filename (default output)\n"
+        );
+    exit(exit_code);
+}
+
+int main(int argc, char **argv)
+{
+    int opt;
+
+    while ((opt = getopt(argc, argv, "h")) != -1) {
+        switch (opt) {
+        case 'h':
+            usage(0);
+            break;
+        default:
+            usage(1);
+        }
+    }
+
+    argv += optind;
+    argc -= optind;
+    if (argc <= 0)
+        usage(1);
+
+    gcov_init();
+
+    if ( strcmp(argv[0], "reset") == 0 )
+        gcov_reset();
+    else if ( strcmp(argv[0], "read") == 0 )
+        gcov_read(argc > 1 ? argv[1] : "-", 0);
+    else if ( strcmp(argv[0], "read-reset") == 0 )
+        gcov_read(argc > 1 ? argv[1] : "-", 1);
+    else
+        usage(1);
+
+    return 0;
+}
+