9:51 p.m.
Add support for reading dumpfiles compressed by Zstandard (zstd)
using makedumpfile.
To build crash with zstd support, type "make zstd".
Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com>
---
v2 -> v3
- add a 'For zstd:' section in the comment above add_extra_lib()
- move ZSTD_createDCtx() into cache_page() and add an error when
it cannot create dctx
- add a sanity check on retlen
Makefile | 4 ++++
README | 4 ++--
configure.c | 24 +++++++++++++++++++++---
defs.h | 4 ++++
diskdump.c | 38 ++++++++++++++++++++++++++++++++++++++
diskdump.h | 1 +
help.c | 4 ++--
7 files changed, 72 insertions(+), 7 deletions(-)
diff --git a/Makefile b/Makefile
index ece13069a029..eae023c54bdd 100644
--- a/Makefile
+++ b/Makefile
@@ -333,6 +333,10 @@ snappy: make_configure
@./configure -x snappy ${CONF_TARGET_FLAG} -w -b
@make --no-print-directory gdb_merge
+zstd: make_configure
+ @./configure -x zstd ${CONF_TARGET_FLAG} -w -b
+ @make --no-print-directory gdb_merge
+
valgrind: make_configure
@./configure -x valgrind ${CONF_TARGET_FLAG} -w -b
@make --no-print-directory gdb_merge
diff --git a/README b/README
index 50179742e620..4962f272074b 100644
--- a/README
+++ b/README
@@ -102,8 +102,8 @@
Traditionally when vmcores are compressed via the makedumpfile(8) facility
the libz compression library is used, and by default the crash utility
only supports libz. Recently makedumpfile has been enhanced to optionally
- use either the LZO or snappy compression libraries. To build crash with
- either or both of those libraries, type "make lzo" or "make
snappy".
+ use the LZO, snappy or zstd compression libraries. To build crash with any
+ or all of those libraries, type "make lzo", "make snappy" or
"make zstd".
crash supports valgrind Memcheck tool on the crash's custom memory allocator.
To build crash with this feature enabled, type "make valgrind" and then run
diff --git a/configure.c b/configure.c
index e8f619a3c061..b691a139b960 100644
--- a/configure.c
+++ b/configure.c
@@ -1738,6 +1738,10 @@ get_extra_flags(char *filename, char *initial)
* - enter -DSNAPPY in the CFLAGS.extra file
* - enter -lsnappy in the LDFLAGS.extra file
*
+ * For zstd:
+ * - enter -DZSTD in the CFLAGS.extra file
+ * - enter -lzstd in the LDFLAGS.extra file
+ *
* For valgrind:
* - enter -DVALGRIND in the CFLAGS.extra file
*/
@@ -1746,6 +1750,7 @@ add_extra_lib(char *option)
{
int lzo, add_DLZO, add_llzo2;
int snappy, add_DSNAPPY, add_lsnappy;
+ int zstd, add_DZSTD, add_lzstd;
int valgrind, add_DVALGRIND;
char *cflags, *ldflags;
FILE *fp_cflags, *fp_ldflags;
@@ -1754,6 +1759,7 @@ add_extra_lib(char *option)
lzo = add_DLZO = add_llzo2 = 0;
snappy = add_DSNAPPY = add_lsnappy = 0;
+ zstd = add_DZSTD = add_lzstd = 0;
valgrind = add_DVALGRIND = 0;
ldflags = get_extra_flags("LDFLAGS.extra", NULL);
@@ -1775,13 +1781,21 @@ add_extra_lib(char *option)
add_lsnappy++;
}
+ if (strcmp(option, "zstd") == 0) {
+ zstd++;
+ if (!cflags || !strstr(cflags, "-DZSTD"))
+ add_DZSTD++;
+ if (!ldflags || !strstr(ldflags, "-lzstd"))
+ add_lzstd++;
+ }
+
if (strcmp(option, "valgrind") == 0) {
valgrind++;
if (!cflags || !strstr(cflags, "-DVALGRIND"))
add_DVALGRIND++;
}
- if ((lzo || snappy) &&
+ if ((lzo || snappy || zstd) &&
file_exists("diskdump.o") && (unlink("diskdump.o") <
0)) {
perror("diskdump.o");
return;
@@ -1806,24 +1820,28 @@ add_extra_lib(char *option)
return;
}
- if (add_DLZO || add_DSNAPPY || add_DVALGRIND) {
+ if (add_DLZO || add_DSNAPPY || add_DZSTD || add_DVALGRIND) {
while (fgets(inbuf, 512, fp_cflags))
;
if (add_DLZO)
fputs("-DLZO\n", fp_cflags);
if (add_DSNAPPY)
fputs("-DSNAPPY\n", fp_cflags);
+ if (add_DZSTD)
+ fputs("-DZSTD\n", fp_cflags);
if (add_DVALGRIND)
fputs("-DVALGRIND\n", fp_cflags);
}
- if (add_llzo2 || add_lsnappy) {
+ if (add_llzo2 || add_lsnappy || add_lzstd) {
while (fgets(inbuf, 512, fp_ldflags))
;
if (add_llzo2)
fputs("-llzo2\n", fp_ldflags);
if (add_lsnappy)
fputs("-lsnappy\n", fp_ldflags);
+ if (add_lzstd)
+ fputs("-lzstd\n", fp_ldflags);
}
fclose(fp_cflags);
diff --git a/defs.h b/defs.h
index eb1c71b5333a..b2e94722c92b 100644
--- a/defs.h
+++ b/defs.h
@@ -54,6 +54,9 @@
#ifdef SNAPPY
#include <snappy-c.h>
#endif
+#ifdef ZSTD
+#include <zstd.h>
+#endif
#ifndef ATTRIBUTE_UNUSED
#define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
@@ -327,6 +330,7 @@ struct number_option {
#define NO_ELF_NOTES (0x20)
#define LZO_SUPPORTED (0x40)
#define SNAPPY_SUPPORTED (0x80)
+#define ZSTD_SUPPORTED (0x100)
#define DISKDUMP_VALID() (dd->flags & DISKDUMP_LOCAL)
#define KDUMP_CMPRS_VALID() (dd->flags & KDUMP_CMPRS_LOCAL)
#define KDUMP_SPLIT() (dd->flags & DUMPFILE_SPLIT)
diff --git a/diskdump.c b/diskdump.c
index de3eeb2c720c..9e80cd3d6f52 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -96,6 +96,10 @@ static struct diskdump_data **dd_list = NULL;
static int num_dd = 0;
static int num_dumpfiles = 0;
+#ifdef ZSTD
+static ZSTD_DCtx *dctx = NULL;
+#endif
+
int dumpfile_is_split(void)
{
return KDUMP_SPLIT();
@@ -1001,6 +1005,9 @@ is_diskdump(char *file)
#ifdef SNAPPY
dd->flags |= SNAPPY_SUPPORTED;
#endif
+#ifdef ZSTD
+ dd->flags |= ZSTD_SUPPORTED;
+#endif
pc->read_vmcoreinfo = vmcoreinfo_read_string;
@@ -1251,6 +1258,33 @@ cache_page(physaddr_t paddr)
ret);
return READ_ERROR;
}
+#endif
+ } else if (pd.flags & DUMP_DH_COMPRESSED_ZSTD) {
+
+ if (!(dd->flags & ZSTD_SUPPORTED)) {
+ error(INFO, "%s: uncompess failed: no zstd compression support\n",
+ DISKDUMP_VALID() ? "diskdump" : "compressed kdump");
+ return READ_ERROR;
+ }
+#ifdef ZSTD
+ if (!dctx)
+ dctx = ZSTD_createDCtx();
+
+ if (!dctx) {
+ error(INFO, "%s: uncompess failed: cannot create ZSTD_DCtx\n",
+ DISKDUMP_VALID() ? "diskdump" : "compressed kdump");
+ return READ_ERROR;
+ }
+
+ retlen = ZSTD_decompressDCtx(dctx,
+ dd->page_cache_hdr[i].pg_bufptr, block_size,
+ dd->compressed_page, pd.size);
+ if (ZSTD_isError(retlen) || (retlen != block_size)) {
+ error(INFO, "%s: uncompress failed: %d (%s)\n",
+ DISKDUMP_VALID() ? "diskdump" : "compressed kdump",
+ retlen, ZSTD_getErrorName(retlen));
+ return READ_ERROR;
+ }
#endif
} else
memcpy(dd->page_cache_hdr[i].pg_bufptr,
@@ -1806,6 +1840,8 @@ __diskdump_memory_dump(FILE *fp)
fprintf(fp, "%sLZO_SUPPORTED", others++ ? "|" : "");
if (dd->flags & SNAPPY_SUPPORTED)
fprintf(fp, "%sSNAPPY_SUPPORTED", others++ ? "|" : "");
+ if (dd->flags & ZSTD_SUPPORTED)
+ fprintf(fp, "%sZSTD_SUPPORTED", others++ ? "|" : "");
fprintf(fp, ") %s\n", FLAT_FORMAT() ? "[FLAT]" :
"");
fprintf(fp, " dfd: %d\n", dd->dfd);
fprintf(fp, " ofp: %lx\n", (ulong)dd->ofp);
@@ -1872,6 +1908,8 @@ __diskdump_memory_dump(FILE *fp)
fprintf(fp, "DUMP_DH_COMPRESSED_LZO");
if (dh->status & DUMP_DH_COMPRESSED_SNAPPY)
fprintf(fp, "DUMP_DH_COMPRESSED_SNAPPY");
+ if (dh->status & DUMP_DH_COMPRESSED_ZSTD)
+ fprintf(fp, "DUMP_DH_COMPRESSED_ZSTD");
if (dh->status & DUMP_DH_COMPRESSED_INCOMPLETE)
fprintf(fp, "DUMP_DH_COMPRESSED_INCOMPLETE");
if (dh->status & DUMP_DH_EXCLUDED_VMEMMAP)
diff --git a/diskdump.h b/diskdump.h
index 28713407b841..c152c7b86616 100644
--- a/diskdump.h
+++ b/diskdump.h
@@ -86,6 +86,7 @@ struct kdump_sub_header {
#define DUMP_DH_COMPRESSED_SNAPPY 0x4 /* page is compressed with snappy */
#define DUMP_DH_COMPRESSED_INCOMPLETE 0x8 /* dumpfile is incomplete */
#define DUMP_DH_EXCLUDED_VMEMMAP 0x10 /* unused vmemmap pages are excluded */
+#define DUMP_DH_COMPRESSED_ZSTD 0x20 /* page is compressed with zstd */
/* descriptor of each page for vmcore */
typedef struct page_desc {
diff --git a/help.c b/help.c
index 6c262a3ffcbb..f34838d59908 100644
--- a/help.c
+++ b/help.c
@@ -9420,8 +9420,8 @@ README_ENTER_DIRECTORY,
" Traditionally when vmcores are compressed via the makedumpfile(8)
facility",
" the libz compression library is used, and by default the crash utility",
" only supports libz. Recently makedumpfile has been enhanced to
optionally",
-" use either the LZO or snappy compression libraries. To build crash with",
-" either or both of those libraries, type \"make lzo\" or \"make
snappy\".",
+" use the LZO, snappy or zstd compression libraries. To build crash with
any",
+" or all of those libraries, type \"make lzo\", \"make snappy\"
or \"make zstd\".",
"",
" crash supports valgrind Memcheck tool on the crash's custom memory
allocator.",
" To build crash with this feature enabled, type \"make valgrind\" and
then run",
--
2.27.0