iov: Factor out hexdumper

Factor out the hexdumper functionality from iov for all to use. Useful for
creating verbose debug printfery that dumps packet data.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: faaac219c55ea586d3f748befaf5a2788fd271b8.1361853677.git.peter.crosthwaite@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

include/qemu-common.h

@@ -442,4 +442,10 @@ int64_t pow2floor(int64_t value);
 int uleb128_encode_small(uint8_t *out, uint32_t n);
 int uleb128_decode_small(const uint8_t *in, uint32_t *n);
 
+/*
+ * Hexdump a buffer to a file. An optional string prefix is added to every line
+ */
+
+void hexdump(const char *buf, FILE *fp, const char *prefix, size_t size);
+
 #endif

util/Makefile.objs

@@ -9,3 +9,4 @@ util-obj-y += error.o qemu-error.o
 util-obj-$(CONFIG_POSIX) += compatfd.o
 util-obj-y += iov.o aes.o qemu-config.o qemu-sockets.o uri.o notify.o
 util-obj-y += qemu-option.o qemu-progress.o
+util-obj-y += hexdump.o

util/hexdump.c

@@ -0,0 +1,37 @@
+/*
+ * Helper to hexdump a buffer
+ *
+ * Copyright (c) 2013 Red Hat, Inc.
+ * Copyright (c) 2013 Gerd Hoffmann <kraxel@redhat.com>
+ * Copyright (c) 2013 Peter Crosthwaite <peter.crosthwaite@xilinx.com>
+ * Copyright (c) 2013 Xilinx, Inc
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include "qemu-common.h"
+
+void hexdump(const char *buf, FILE *fp, const char *prefix, size_t size)
+{
+    unsigned int b;
+
+    for (b = 0; b < size; b++) {
+        if ((b % 16) == 0) {
+            fprintf(fp, "%s: %04x:", prefix, b);
+        }
+        if ((b % 4) == 0) {
+            fprintf(fp, " ");
+        }
+        fprintf(fp, " %02x", (unsigned char)buf[b]);
+        if ((b % 16) == 15) {
+            fprintf(fp, "\n");
+        }
+    }
+    if ((b % 16) != 0) {
+        fprintf(fp, "\n");
+    }
+}

util/iov.c

@@ -201,32 +201,18 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
 void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
                  FILE *fp, const char *prefix, size_t limit)
 {
-    unsigned int i, v, b;
-    uint8_t *c;
-
-    c = iov[0].iov_base;
-    for (i = 0, v = 0, b = 0; b < limit; i++, b++) {
-        if (i == iov[v].iov_len) {
-            i = 0; v++;
-            if (v == iov_cnt) {
-                break;
-            }
-            c = iov[v].iov_base;
-        }
-        if ((b % 16) == 0) {
-            fprintf(fp, "%s: %04x:", prefix, b);
-        }
-        if ((b % 4) == 0) {
-            fprintf(fp, " ");
-        }
-        fprintf(fp, " %02x", c[i]);
-        if ((b % 16) == 15) {
-            fprintf(fp, "\n");
-        }
-    }
-    if ((b % 16) != 0) {
-        fprintf(fp, "\n");
+    int v;
+    size_t size = 0;
+    char *buf;
+
+    for (v = 0; v < iov_cnt; v++) {
+        size += iov[v].iov_len;
     }
+    size = size > limit ? limit : size;
+    buf = g_malloc(size);
+    iov_to_buf(iov, iov_cnt, 0, buf, size);
+    hexdump(buf, fp, prefix, size);
+    g_free(buf);
 }
 
 unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt,