[Crash-utility] [PATCH] diskdump: Add support for reading dumpfiles compressed by Zstandard

Hi, Tao Liu posted the patchset that adds zstd support to makedumpfile [1], this is a corresponding patch for crash. [1] http://lists.infradead.org/pipermail/kexec/2021-September/023011.html -- From: Kazuhito Hagio <k-hagio(a)ab.jp.nec.com&gt; Date: Thu, 12 Sep 2019 11:53:08 -0400 Subject: [PATCH] diskdump: Add support for reading dumpfiles compressed by Zstandard 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&gt; --- Makefile | 4 ++++ README | 4 ++-- configure.c | 20 +++++++++++++++++--- defs.h | 4 ++++ diskdump.c | 31 +++++++++++++++++++++++++++++++ diskdump.h | 1 + help.c | 4 ++-- 7 files changed, 61 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..9548720ef64a 100644 --- a/configure.c +++ b/configure.c @@ -1746,6 +1746,7 @@ 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 +1755,7 @@ 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 +1777,21 @@ 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 +1816,28 @@ 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..f1e890acbf58 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(); @@ -1002,6 +1006,11 @@ is_diskdump(char *file) dd->flags |= SNAPPY_SUPPORTED; #endif +#ifdef ZSTD + if ((dctx = ZSTD_createDCtx()) != NULL) + dd->flags |= ZSTD_SUPPORTED; +#endif + pc->read_vmcoreinfo = vmcoreinfo_read_string; if ((pc->flags2 & GET_LOG) && KDUMP_CMPRS_VALID()) { @@ -1251,6 +1260,24 @@ 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: uncompress failed: no zstd compression support\n", + DISKDUMP_VALID() ? "diskdump" : "compressed kdump"); + return READ_ERROR; + } +#ifdef ZSTD + retlen = ZSTD_decompressDCtx(dctx, + dd->page_cache_hdr[i].pg_bufptr, block_size, + dd->compressed_page, pd.size); + if (ZSTD_isError(retlen)) { + 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 +1833,8 @@ __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 +1901,8 @@ __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