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Subject[PATCH v4 6/7] lib/hexdump.c: Allow multiple groups to be separated by spaces
Date
From: Alastair D'Silva <alastair@d-silva.org>

Similar to the previous patch, this patch separates groups by 2 spaces for
the hex fields, and 1 space for the ASCII field.

eg.
buf:00000000: 454d414e 43415053 4e495f45 00584544 NAMESPAC E_INDEX.
buf:00000010: 00000000 00000002 00000000 00000000 ........ ........

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
include/linux/printk.h | 3 ++
lib/hexdump.c | 65 +++++++++++++++++++++++++++++++-----------
2 files changed, 52 insertions(+), 16 deletions(-)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index ae80d7af82ab..1d082291facf 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -488,6 +488,9 @@ enum {
#define HEXDUMP_2_GRP_LINES BIT(2)
#define HEXDUMP_4_GRP_LINES BIT(3)
#define HEXDUMP_8_GRP_LINES BIT(4)
+#define HEXDUMP_2_GRP_SPACES BIT(5)
+#define HEXDUMP_4_GRP_SPACES BIT(6)
+#define HEXDUMP_8_GRP_SPACES BIT(7)

extern int hex_dump_to_buffer_ext(const void *buf, size_t len, int rowsize,
int groupsize, char *linebuf, size_t linebuflen,
diff --git a/lib/hexdump.c b/lib/hexdump.c
index 4dcf759fe048..e09e3cf8e595 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -91,9 +91,37 @@ static const char *group_separator(int group, u64 flags)
if ((flags & HEXDUMP_2_GRP_LINES) && !((group) % 2))
return "|";

+ if ((flags & HEXDUMP_8_GRP_SPACES) && !((group) % 8))
+ return " ";
+
+ if ((flags & HEXDUMP_4_GRP_SPACES) && !((group) % 4))
+ return " ";
+
+ if ((flags & HEXDUMP_2_GRP_SPACES) && !((group) % 2))
+ return " ";
+
return " ";
}

+static void separator_parameters(u64 flags, int groupsize, int *sep_chars,
+ char *sep)
+{
+ if (flags & (HEXDUMP_2_GRP_LINES | HEXDUMP_2_GRP_SPACES))
+ *sep_chars = groupsize * 2;
+ if (flags & (HEXDUMP_4_GRP_LINES | HEXDUMP_4_GRP_SPACES))
+ *sep_chars = groupsize * 4;
+ if (flags & (HEXDUMP_8_GRP_LINES | HEXDUMP_8_GRP_SPACES))
+ *sep_chars = groupsize * 8;
+
+ if (flags & (HEXDUMP_2_GRP_LINES | HEXDUMP_4_GRP_LINES |
+ HEXDUMP_8_GRP_LINES))
+ *sep = '|';
+
+ if (flags & (HEXDUMP_2_GRP_SPACES | HEXDUMP_4_GRP_SPACES |
+ HEXDUMP_8_GRP_SPACES))
+ *sep = ' ';
+}
+
/**
* hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
* @buf: data blob to dump
@@ -107,6 +135,9 @@ static const char *group_separator(int group, u64 flags)
* HEXDUMP_2_GRP_LINES: insert a '|' after every 2 groups
* HEXDUMP_4_GRP_LINES: insert a '|' after every 4 groups
* HEXDUMP_8_GRP_LINES: insert a '|' after every 8 groups
+ * HEXDUMP_2_GRP_SPACES: insert a ' ' after every 2 groups
+ * HEXDUMP_4_GRP_SPACES: insert a ' ' after every 4 groups
+ * HEXDUMP_8_GRP_SPACES: insert a ' ' after every 8 groups
*
* hex_dump_to_buffer() works on one "line" of output at a time, converting
* <groupsize> bytes of input to hexadecimal (and optionally printable ASCII)
@@ -139,7 +170,8 @@ int hex_dump_to_buffer_ext(const void *buf, size_t len, int rowsize,
int j, lx = 0;
int ascii_column;
int ret;
- int line_chars = 0;
+ int sep_chars = 0;
+ char sep = 0;

if (!is_power_of_2(groupsize) || groupsize > 8)
groupsize = 1;
@@ -153,8 +185,14 @@ int hex_dump_to_buffer_ext(const void *buf, size_t len, int rowsize,
len = rowsize;

ngroups = len / groupsize;
+
ascii_column = rowsize * 2 + rowsize / groupsize + 1;

+ // space separators use 2 spaces in the hex output
+ separator_parameters(flags, groupsize, &sep_chars, &sep);
+ if (sep == ' ')
+ ascii_column += rowsize / sep_chars;
+
if (!linebuflen)
goto overflow1;

@@ -222,24 +260,17 @@ int hex_dump_to_buffer_ext(const void *buf, size_t len, int rowsize,
linebuf[lx++] = ' ';
}

- if (flags & HEXDUMP_2_GRP_LINES)
- line_chars = groupsize * 2;
- if (flags & HEXDUMP_4_GRP_LINES)
- line_chars = groupsize * 4;
- if (flags & HEXDUMP_8_GRP_LINES)
- line_chars = groupsize * 8;
-
for (j = 0; j < len; j++) {
if (linebuflen < lx + 2)
goto overflow2;
ch = ptr[j];
linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';

- if (line_chars && ((j + 1) < len) &&
- ((j + 1) % line_chars == 0)) {
+ if (sep_chars && ((j + 1) < len) &&
+ ((j + 1) % sep_chars == 0)) {
if (linebuflen < lx + 2)
goto overflow2;
- linebuf[lx++] = '|';
+ linebuf[lx++] = sep;
}
}
nil:
@@ -248,9 +279,11 @@ int hex_dump_to_buffer_ext(const void *buf, size_t len, int rowsize,
overflow2:
linebuf[lx++] = '\0';
overflow1:
- return (flags & HEXDUMP_ASCII) ? ascii_column + len +
- (len - 1) / line_chars :
- (groupsize * 2 + 1) * ngroups - 1;
+ if (flags & HEXDUMP_ASCII)
+ return ascii_column + len + (len - 1) / sep_chars;
+
+ return groupsize * 2 * ngroups +
+ ((sep == ' ') ? 2 : 1) * (ngroups - 1);
}
EXPORT_SYMBOL(hex_dump_to_buffer_ext);

@@ -345,9 +378,9 @@ void print_hex_dump_ext(const char *level, const char *prefix_str,
/*
* Worst case line length:
* 2 hex chars + space per byte in, 2 spaces, 1 char per byte in,
- * 1 char per N groups, NULL
+ * 2 char per N groups, NULL
*/
- linebuf_len = rowsize * 3 + 2 + rowsize + rowsize / groupsize + 1;
+ linebuf_len = rowsize * 3 + 2 + rowsize + 2 * rowsize / groupsize + 1;
linebuf = kzalloc(linebuf_len, GFP_KERNEL);
if (!linebuf) {
printk("%s%shexdump: Could not alloc %u bytes for buffer\n",
--
2.21.0
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