Hi,
I've been implementing pretty printing in pahole:
[acme@quaco pahole]$ git log --oneline v1.17..
5631fdcea1bb (HEAD -> master, acme.korg/pretty, acme.korg/master) pahole: Introduce --count, just like dd's
272bc75024b4 man-pages: Add information about stdin raw data pretty printing
66835f9e190c pahole: Add support for base type arrays
1a67d6e70090 pahole: Factor out base_type__fprintf_value()
6fb98aa1209f pahole: Support char arrays when dumping from stdin
a231d00f8d08 pahole: Print comma at the end of field name + field value
1b2cdda38c0a dwarves: Introduce tag__is_array()
a83313fb2252 pahole: Pretty print base types in structs from stdin
cc65946e3068 dwarves: Adopt tag__is_base_type() from ctrace.c
d8079c6d373a pahole: Hex dump a type from stdio when it isn't a tty
38109ab45fe0 spec: Fix date
[acme@quaco pahole]$
The latest changeset shows what this is about, see its example
below, please help testing and suggesting whatever needs you have
regarding pretty printing.
Now to implement --skip.
Regards,
- Arnaldo
>From 5631fdcea1bbe2bcb8c673ff0bb0fdc9fdc2875d Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Date: Wed, 1 Jul 2020 08:14:58 -0300
Subject: [PATCH] pahole: Introduce --count, just like dd's
$ objcopy -O binary --only-section=.altinstructions ~/git/build/v5.7-rc2+/vmlinux .altinstructions
$ pahole --count 2 alt_instr < .altinstructions
{
.instr_offset = 0xffffffffffe0e690,
.repl_offset = 0x4873,
.cpuid = 0x70,
.instrlen = 0x5,
.replacementlen = 0x5,
.padlen = 0,
},
{
.instr_offset = 0xffffffffffe0e683,
.repl_offset = 0x486b,
.cpuid = 0x129,
.instrlen = 0x5,
.replacementlen = 0x5,
.padlen = 0,
},
$
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
dwarves.h | 2 ++
man-pages/pahole.1 | 8 +++++++-
pahole.c | 13 +++++++++++++
3 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/dwarves.h b/dwarves.h
index 0170f251bcd4..f224d05b28c3 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -54,6 +54,7 @@ struct conf_load {
/** struct conf_fprintf - hints to the __fprintf routines
*
+ * @count - Just like 'dd', stop pretty printing input after 'count' records
* @flat_arrays - a->foo[10][2] becomes a->foo[20]
* @classes_as_structs - class f becomes struct f, CTF doesn't have a "class"
* @cachelinep - pointer to current cacheline, so that when expanding types we keep track of it,
@@ -68,6 +69,7 @@ struct conf_fprintf {
int32_t type_spacing;
int32_t name_spacing;
uint32_t base_offset;
+ uint32_t count;
uint32_t *cachelinep;
uint8_t indent;
uint8_t expand_types:1;
diff --git a/man-pages/pahole.1 b/man-pages/pahole.1
index 26c14cb6fd2c..7e8207756432 100644
--- a/man-pages/pahole.1
+++ b/man-pages/pahole.1
@@ -60,6 +60,8 @@ See the EXAMPLES section for more usage suggestions.
It also pretty prints whatever is fed to its standard input, according to the
type specified, see the EXAMPLE session.
+Use --count to state how many records should be pretty printed.
+
.SH OPTIONS
pahole supports the following options.
@@ -72,6 +74,10 @@ or file URLs (e.g.: file://class_list.txt)
.B \-c, \-\-cacheline_size=SIZE
Set cacheline size to SIZE bytes.
+.TP
+.B \-\-count=COUNT
+Pretty print the first COUNT records from input.
+
.TP
.B \-E, \-\-expand_types
Expand class members. Useful to find in what member of inner structs where an
@@ -482,7 +488,7 @@ $
$ ls -la versions
-rw-rw-r--. 1 acme acme 7616 Jun 25 11:33 versions
$
-$ pahole -C modversion_info drivers/scsi/sg.ko < versions | head -12
+$ pahole --count 3 -C modversion_info drivers/scsi/sg.ko < versions
{
.crc = 0x8dabd84,
.name = "module_layout",
diff --git a/pahole.c b/pahole.c
index 03909525bf15..1b84f5c2fa4a 100644
--- a/pahole.c
+++ b/pahole.c
@@ -802,6 +802,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version;
#define ARGP_suppress_packed 308
#define ARGP_just_unions 309
#define ARGP_just_structs 310
+#define ARGP_count 311
static const struct argp_option pahole__options[] = {
{
@@ -822,6 +823,12 @@ static const struct argp_option pahole__options[] = {
.arg = "CLASS_NAME",
.doc = "Show just this class"
},
+ {
+ .name = "count",
+ .key = ARGP_count,
+ .arg = "COUNT",
+ .doc = "Print only COUNT input records"
+ },
{
.name = "find_pointers_to",
.key = 'f',
@@ -1145,6 +1152,8 @@ static error_t pahole__options_parser(int key, char *arg,
just_unions = true; break;
case ARGP_just_structs:
just_structs = true; break;
+ case ARGP_count:
+ conf.count = atoi(arg); break;
default:
return ARGP_ERR_UNKNOWN;
}
@@ -1315,6 +1324,7 @@ static int tag__stdio_fprintf_value(struct tag *type, struct cu *cu, FILE *fp)
{
int _sizeof = tag__size(type, cu), printed = 0;
void *instance = malloc(_sizeof);
+ uint32_t count = 0;
if (instance == NULL)
return -ENOMEM;
@@ -1322,6 +1332,9 @@ static int tag__stdio_fprintf_value(struct tag *type, struct cu *cu, FILE *fp)
while (fread(instance, _sizeof, 1, stdin) == 1) {
printed += tag__fprintf_value(type, cu, instance, _sizeof, fp);
printed += fprintf(fp, ",\n");
+
+ if (conf.count && ++count == conf.count)
+ break;
}
return printed;
--
2.21.3
