In the kernel hex_dump_to_buffer() got an int return value, returning
the amount of bytes written into the buffer. This new return value is
needed by seq_hex_dump() which we also backport.
This change was done in the following commit in mainline Linux kernel:
commit 114fc1afb2de7dec40da137dc2a55cd38fc220f2
Author: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Date: Thu Feb 12 15:02:29 2015 -0800
hexdump: make it return number of bytes placed in buffer
Signed-off-by: Hauke Mehrtens <hauke@xxxxxxxxxx>
---
backport/backport-include/linux/printk.h | 8 ++
backport/compat/backport-4.0.c | 132 +++++++++++++++++++++++++++++++
2 files changed, 140 insertions(+)
diff --git a/backport/backport-include/linux/printk.h b/backport/backport-include/linux/printk.h
index 88989a9..d8083ac 100644
--- a/backport/backport-include/linux/printk.h
+++ b/backport/backport-include/linux/printk.h
@@ -138,6 +138,14 @@ do { \
#endif
#endif /* pr_debug_ratelimited */
+/* replace hex_dump_to_buffer() with a version which returns the length */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,0,0)
+#define hex_dump_to_buffer LINUX_BACKPORT(hex_dump_to_buffer)
+extern int hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
+ int groupsize, char *linebuf, size_t linebuflen,
+ bool ascii);
+#endif
+
#endif /* _COMPAT_LINUX_PRINTK_H */
/* This must be outside -- see also kernel.h */
diff --git a/backport/compat/backport-4.0.c b/backport/compat/backport-4.0.c
index 3de1211..acec0af 100644
--- a/backport/compat/backport-4.0.c
+++ b/backport/compat/backport-4.0.c
@@ -11,7 +11,10 @@
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
+#include <linux/ctype.h>
+#include <linux/printk.h>
#include <linux/export.h>
+#include <asm/unaligned.h>
static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
struct mm_struct *mm,
@@ -191,3 +194,132 @@ long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
force, pages, FOLL_TOUCH);
}
EXPORT_SYMBOL_GPL(get_user_pages_unlocked);
+
+
+/**
+ * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
+ * @buf: data blob to dump
+ * @len: number of bytes in the @buf
+ * @rowsize: number of bytes to print per line; must be 16 or 32
+ * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
+ * @linebuf: where to put the converted data
+ * @linebuflen: total size of @linebuf, including space for terminating NUL
+ * @ascii: include ASCII after the hex output
+ *
+ * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
+ * 16 or 32 bytes of input data converted to hex + ASCII output.
+ *
+ * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
+ * to a hex + ASCII dump at the supplied memory location.
+ * The converted output is always NUL-terminated.
+ *
+ * E.g.:
+ * hex_dump_to_buffer(frame->data, frame->len, 16, 1,
+ * linebuf, sizeof(linebuf), true);
+ *
+ * example output buffer:
+ * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
+ *
+ * Return:
+ * The amount of bytes placed in the buffer without terminating NUL. If the
+ * output was truncated, then the return value is the number of bytes
+ * (excluding the terminating NUL) which would have been written to the final
+ * string if enough space had been available.
+ */
+int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
+ char *linebuf, size_t linebuflen, bool ascii)
+{
+ const u8 *ptr = buf;
+ int ngroups;
+ u8 ch;
+ int j, lx = 0;
+ int ascii_column;
+ int ret;
+
+ if (rowsize != 16 && rowsize != 32)
+ rowsize = 16;
+
+ if (len > rowsize) /* limit to one line at a time */
+ len = rowsize;
+ if (!is_power_of_2(groupsize) || groupsize > 8)
+ groupsize = 1;
+ if ((len % groupsize) != 0) /* no mixed size output */
+ groupsize = 1;
+
+ ngroups = len / groupsize;
+ ascii_column = rowsize * 2 + rowsize / groupsize + 1;
+
+ if (!linebuflen)
+ goto overflow1;
+
+ if (!len)
+ goto nil;
+
+ if (groupsize == 8) {
+ const u64 *ptr8 = buf;
+
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%16.16llx", j ? " " : "",
+ get_unaligned(ptr8 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
+ } else if (groupsize == 4) {
+ const u32 *ptr4 = buf;
+
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%8.8x", j ? " " : "",
+ get_unaligned(ptr4 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
+ } else if (groupsize == 2) {
+ const u16 *ptr2 = buf;
+
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%4.4x", j ? " " : "",
+ get_unaligned(ptr2 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
+ } else {
+ for (j = 0; j < len; j++) {
+ if (linebuflen < lx + 3)
+ goto overflow2;
+ ch = ptr[j];
+ linebuf[lx++] = hex_asc_hi(ch);
+ linebuf[lx++] = hex_asc_lo(ch);
+ linebuf[lx++] = ' ';
+ }
+ if (j)
+ lx--;
+ }
+ if (!ascii)
+ goto nil;
+
+ while (lx < ascii_column) {
+ if (linebuflen < lx + 2)
+ goto overflow2;
+ linebuf[lx++] = ' ';
+ }
+ for (j = 0; j < len; j++) {
+ if (linebuflen < lx + 2)
+ goto overflow2;
+ ch = ptr[j];
+ linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
+ }
+nil:
+ linebuf[lx] = '\0';
+ return lx;
+overflow2:
+ linebuf[lx++] = '\0';
+overflow1:
+ return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
+}
+EXPORT_SYMBOL_GPL(hex_dump_to_buffer);
--
2.1.4
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