[PATCH v2 3/5] tools/misc: add xen-domctx to present domain context

[Paul Durrant <paul@xen.org>]

This tool is analogous to 'xen-hvmctx' which presents HVM context.
Subsequent patches will add 'dump' functions when new records are
introduced.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Wei Liu <wl@xen.org>

v2:
 - Change name from 'xen-ctx' to 'xen-domctx'
---
 .gitignore              |   1 +
 tools/misc/Makefile     |   4 ++
 tools/misc/xen-domctx.c | 145 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 150 insertions(+)
 create mode 100644 tools/misc/xen-domctx.c

diff --git a/.gitignore b/.gitignore
index 4ca679ddbc..744c0529bb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -208,6 +208,7 @@ tools/misc/xen_cpuperf
 tools/misc/xen-cpuid
 tools/misc/xen-detect
 tools/misc/xen-diag
+tools/misc/xen-domctx
 tools/misc/xen-tmem-list-parse
 tools/misc/xen-livepatch
 tools/misc/xenperf
diff --git a/tools/misc/Makefile b/tools/misc/Makefile
index 63947bfadc..ef25524354 100644
--- a/tools/misc/Makefile
+++ b/tools/misc/Makefile
@@ -30,6 +30,7 @@ INSTALL_SBIN                   += xenpm
 INSTALL_SBIN                   += xenwatchdogd
 INSTALL_SBIN                   += xen-livepatch
 INSTALL_SBIN                   += xen-diag
+INSTALL_SBIN                   += xen-domctx
 INSTALL_SBIN += $(INSTALL_SBIN-y)
 
 # Everything to be installed in a private bin/
@@ -108,6 +109,9 @@ xen-livepatch: xen-livepatch.o
 xen-diag: xen-diag.o
 	$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
 
+xen-domctx: xen-domctx.o
+	$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
+
 xen-lowmemd: xen-lowmemd.o
 	$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenevtchn) $(LDLIBS_libxenctrl) $(LDLIBS_libxenstore) $(APPEND_LDFLAGS)
 
diff --git a/tools/misc/xen-domctx.c b/tools/misc/xen-domctx.c
new file mode 100644
index 0000000000..d663522a8b
--- /dev/null
+++ b/tools/misc/xen-domctx.c
@@ -0,0 +1,145 @@
+/*
+ * xen-domctx.c
+ *
+ * Print out domain save records in a human-readable way.
+ *
+ * Copyright Amazon.com Inc. or its affiliates.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <xenctrl.h>
+#include <xen/xen.h>
+#include <xen/domctl.h>
+#include <xen/save.h>
+
+static void *buf = NULL;
+static size_t len, off;
+
+#define READ(_x) do {                                                   \
+    if ( len - off < sizeof (_x) )                                      \
+    {                                                                   \
+        fprintf(stderr,                                                 \
+                "Error: need another %lu bytes, only %lu available\n",  \
+                sizeof(_x), len - off);                                 \
+        exit(1);                                                        \
+    }                                                                   \
+    memcpy(&(_x), buf + off, sizeof (_x));                              \
+} while (0)
+
+static void dump_header(struct domain_save_descriptor *desc)
+{
+    DOMAIN_SAVE_TYPE(HEADER) h;
+    READ(h);
+    printf("    HEADER: magic %#x, version %u\n",
+           h.magic, h.version);
+
+    off += desc->length;
+}
+
+static void dump_end(struct domain_save_descriptor *desc)
+{
+    DOMAIN_SAVE_TYPE(END) e;
+    READ(e);
+    printf("    END\n");
+}
+
+int main(int argc, char **argv)
+{
+    uint32_t domid;
+    unsigned int entry;
+    xc_interface *xch;
+    int rc;
+
+    if ( argc != 2 || !argv[1] || (rc = atoi(argv[1])) < 0 )
+    {
+        fprintf(stderr, "usage: %s <domid>\n", argv[0]);
+        exit(1);
+    }
+    domid = rc;
+
+    xch = xc_interface_open(0,0,0);
+    if ( !xch )
+    {
+        fprintf(stderr, "Error: can't open libxc handle\n");
+        exit(1);
+    }
+
+    rc = xc_domain_getcontext(xch, domid, NULL, &len);
+    if ( rc < 0 )
+    {
+        fprintf(stderr, "Error: can't get record length for dom %u: %s\n",
+                domid, strerror(errno));
+        exit(1);
+    }
+
+    buf = malloc(len);
+    if ( !buf )
+    {
+        fprintf(stderr, "Error: can't allocate %lu bytes\n", len);
+        exit(1);
+    }
+
+    rc = xc_domain_getcontext(xch, domid, buf, &len);
+    if ( rc < 0 )
+    {
+        fprintf(stderr, "Error: can't get domain record for dom %u: %s\n",
+                domid, strerror(errno));
+        exit(1);
+    }
+    off = 0;
+
+    printf("Domain save records for d%u\n", domid);
+
+    entry = 0;
+    for (;;) {
+        struct domain_save_descriptor desc;
+
+        READ(desc);
+        printf("[%u] type %u v%u, length %lu\n", entry++,
+               desc.typecode, desc.vcpu_id, (unsigned long)desc.length);
+        off += sizeof(desc);
+
+        switch (desc.typecode)
+        {
+        case DOMAIN_SAVE_CODE(HEADER): dump_header(&desc); break;
+        case DOMAIN_SAVE_CODE(END): dump_end(&desc); return 0;
+        default:
+            printf("Unknown type %u: skipping\n", desc.typecode);
+            off += desc.length;
+            break;
+        }
+    }
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
2.20.1