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qemu
dump-Add-architecture-section-and-sectio.patch
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File dump-Add-architecture-section-and-sectio.patch of Package qemu
From: Janosch Frank <frankja@linux.ibm.com> Date: Mon, 17 Oct 2022 11:32:10 +0000 Subject: dump: Add architecture section and section string table support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Git-commit: 9b72224f44612ddd5b434a1bccf79346946d11da References: jsc#PED-1716 Add hooks which architectures can use to add arbitrary data to custom sections. Also add a section name string table in order to identify section contents Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20221017113210.41674-1-frankja@linux.ibm.com> Signed-off-by: Li Zhang <lizhang@suse.de> --- dump/dump.c | 186 +++++++++++++++++++++++++++++++------ include/sysemu/dump-arch.h | 3 + include/sysemu/dump.h | 3 + 3 files changed, 166 insertions(+), 26 deletions(-) diff --git a/dump/dump.c b/dump/dump.c index a19d2420efe9575e97b8ba13d0ca..eb547e3e59e90681cddfc8c4080d 100644 --- a/dump/dump.c +++ b/dump/dump.c @@ -103,6 +103,7 @@ static int dump_cleanup(DumpState *s) memory_mapping_list_free(&s->list); close(s->fd); g_free(s->guest_note); + g_array_unref(s->string_table_buf); s->guest_note = NULL; if (s->resume) { if (s->detached) { @@ -152,11 +153,10 @@ static void prepare_elf64_header(DumpState *s, Elf64_Ehdr *elf_header) elf_header->e_phoff = cpu_to_dump64(s, s->phdr_offset); elf_header->e_phentsize = cpu_to_dump16(s, sizeof(Elf64_Phdr)); elf_header->e_phnum = cpu_to_dump16(s, phnum); - if (s->shdr_num) { - elf_header->e_shoff = cpu_to_dump64(s, s->shdr_offset); - elf_header->e_shentsize = cpu_to_dump16(s, sizeof(Elf64_Shdr)); - elf_header->e_shnum = cpu_to_dump16(s, s->shdr_num); - } + elf_header->e_shoff = cpu_to_dump64(s, s->shdr_offset); + elf_header->e_shentsize = cpu_to_dump16(s, sizeof(Elf64_Shdr)); + elf_header->e_shnum = cpu_to_dump16(s, s->shdr_num); + elf_header->e_shstrndx = cpu_to_dump16(s, s->shdr_num - 1); } static void prepare_elf32_header(DumpState *s, Elf32_Ehdr *elf_header) @@ -180,11 +180,10 @@ static void prepare_elf32_header(DumpState *s, Elf32_Ehdr *elf_header) elf_header->e_phoff = cpu_to_dump32(s, s->phdr_offset); elf_header->e_phentsize = cpu_to_dump16(s, sizeof(Elf32_Phdr)); elf_header->e_phnum = cpu_to_dump16(s, phnum); - if (s->shdr_num) { - elf_header->e_shoff = cpu_to_dump32(s, s->shdr_offset); - elf_header->e_shentsize = cpu_to_dump16(s, sizeof(Elf32_Shdr)); - elf_header->e_shnum = cpu_to_dump16(s, s->shdr_num); - } + elf_header->e_shoff = cpu_to_dump32(s, s->shdr_offset); + elf_header->e_shentsize = cpu_to_dump16(s, sizeof(Elf32_Shdr)); + elf_header->e_shnum = cpu_to_dump16(s, s->shdr_num); + elf_header->e_shstrndx = cpu_to_dump16(s, s->shdr_num - 1); } static void write_elf_header(DumpState *s, Error **errp) @@ -195,6 +194,8 @@ static void write_elf_header(DumpState *s, Error **errp) void *header_ptr; int ret; + /* The NULL header and the shstrtab are always defined */ + assert(s->shdr_num >= 2); if (dump_is_64bit(s)) { prepare_elf64_header(s, &elf64_header); header_size = sizeof(elf64_header); @@ -393,17 +394,49 @@ static void prepare_elf_section_hdr_zero(DumpState *s) } } -static void prepare_elf_section_hdrs(DumpState *s) +static void prepare_elf_section_hdr_string(DumpState *s, void *buff) +{ + uint64_t index = s->string_table_buf->len; + const char strtab[] = ".shstrtab"; + Elf32_Shdr shdr32 = {}; + Elf64_Shdr shdr64 = {}; + int shdr_size; + void *shdr; + + g_array_append_vals(s->string_table_buf, strtab, sizeof(strtab)); + if (dump_is_64bit(s)) { + shdr_size = sizeof(Elf64_Shdr); + shdr64.sh_type = SHT_STRTAB; + shdr64.sh_offset = s->section_offset + s->elf_section_data_size; + shdr64.sh_name = index; + shdr64.sh_size = s->string_table_buf->len; + shdr = &shdr64; + } else { + shdr_size = sizeof(Elf32_Shdr); + shdr32.sh_type = SHT_STRTAB; + shdr32.sh_offset = s->section_offset + s->elf_section_data_size; + shdr32.sh_name = index; + shdr32.sh_size = s->string_table_buf->len; + shdr = &shdr32; + } + memcpy(buff, shdr, shdr_size); +} + +static bool prepare_elf_section_hdrs(DumpState *s, Error **errp) { size_t len, sizeof_shdr; + void *buff_hdr; /* * Section ordering: * - HDR zero + * - Arch section hdrs + * - String table hdr */ sizeof_shdr = dump_is_64bit(s) ? sizeof(Elf64_Shdr) : sizeof(Elf32_Shdr); len = sizeof_shdr * s->shdr_num; s->elf_section_hdrs = g_malloc0(len); + buff_hdr = s->elf_section_hdrs; /* * The first section header is ALWAYS a special initial section @@ -419,6 +452,26 @@ static void prepare_elf_section_hdrs(DumpState *s) if (s->phdr_num >= PN_XNUM) { prepare_elf_section_hdr_zero(s); } + buff_hdr += sizeof_shdr; + + /* Add architecture defined section headers */ + if (s->dump_info.arch_sections_write_hdr_fn + && s->shdr_num > 2) { + buff_hdr += s->dump_info.arch_sections_write_hdr_fn(s, buff_hdr); + + if (s->shdr_num >= SHN_LORESERVE) { + error_setg_errno(errp, EINVAL, + "dump: too many architecture defined sections"); + return false; + } + } + + /* + * String table is the last section since strings are added via + * arch_sections_write_hdr(). + */ + prepare_elf_section_hdr_string(s, buff_hdr); + return true; } static void write_elf_section_headers(DumpState *s, Error **errp) @@ -426,7 +479,9 @@ static void write_elf_section_headers(DumpState *s, Error **errp) size_t sizeof_shdr = dump_is_64bit(s) ? sizeof(Elf64_Shdr) : sizeof(Elf32_Shdr); int ret; - prepare_elf_section_hdrs(s); + if (!prepare_elf_section_hdrs(s, errp)) { + return; + } ret = fd_write_vmcore(s->elf_section_hdrs, s->shdr_num * sizeof_shdr, s); if (ret < 0) { @@ -436,6 +491,29 @@ static void write_elf_section_headers(DumpState *s, Error **errp) g_free(s->elf_section_hdrs); } +static void write_elf_sections(DumpState *s, Error **errp) +{ + int ret; + + if (s->elf_section_data_size) { + /* Write architecture section data */ + ret = fd_write_vmcore(s->elf_section_data, + s->elf_section_data_size, s); + if (ret < 0) { + error_setg_errno(errp, -ret, + "dump: failed to write architecture section data"); + return; + } + } + + /* Write string table */ + ret = fd_write_vmcore(s->string_table_buf->data, + s->string_table_buf->len, s); + if (ret < 0) { + error_setg_errno(errp, -ret, "dump: failed to write string table data"); + } +} + static void write_data(DumpState *s, void *buf, int length, Error **errp) { int ret; @@ -692,6 +770,31 @@ static void dump_iterate(DumpState *s, Error **errp) } } +static void dump_end(DumpState *s, Error **errp) +{ + int rc; + ERRP_GUARD(); + + if (s->elf_section_data_size) { + s->elf_section_data = g_malloc0(s->elf_section_data_size); + } + + /* Adds the architecture defined section data to s->elf_section_data */ + if (s->dump_info.arch_sections_write_fn && + s->elf_section_data_size) { + rc = s->dump_info.arch_sections_write_fn(s, s->elf_section_data); + if (rc) { + error_setg_errno(errp, rc, + "dump: failed to get arch section data"); + g_free(s->elf_section_data); + return; + } + } + + /* write sections to vmcore */ + write_elf_sections(s, errp); +} + static void create_vmcore(DumpState *s, Error **errp) { ERRP_GUARD(); @@ -701,7 +804,14 @@ static void create_vmcore(DumpState *s, Error **errp) return; } + /* Iterate over memory and dump it to file */ dump_iterate(s, errp); + if (*errp) { + return; + } + + /* Write the section data */ + dump_end(s, errp); } static int write_start_flat_header(int fd) @@ -1683,6 +1793,14 @@ static void dump_init(DumpState *s, int fd, bool has_format, s->filter_area_begin = begin; s->filter_area_length = length; + /* First index is 0, it's the special null name */ + s->string_table_buf = g_array_new(FALSE, TRUE, 1); + /* + * Allocate the null name, due to the clearing option set to true + * it will be 0. + */ + g_array_set_size(s->string_table_buf, 1); + memory_mapping_list_init(&s->list); guest_phys_blocks_init(&s->guest_phys_blocks); @@ -1819,26 +1937,42 @@ static void dump_init(DumpState *s, int fd, bool has_format, } /* - * calculate phdr_num + * The first section header is always a special one in which most + * fields are 0. The section header string table is also always + * set. + */ + s->shdr_num = 2; + + /* + * Adds the number of architecture sections to shdr_num and sets + * elf_section_data_size so we know the offsets and sizes of all + * parts. + */ + if (s->dump_info.arch_sections_add_fn) { + s->dump_info.arch_sections_add_fn(s); + } + + /* + * calculate shdr_num so we know the offsets and sizes of all + * parts. + * Calculate phdr_num * - * the type of ehdr->e_phnum is uint16_t, so we should avoid overflow + * The absolute maximum amount of phdrs is UINT32_MAX - 1 as + * sh_info is 32 bit. There's special handling once we go over + * UINT16_MAX - 1 but that is handled in the ehdr and section + * code. */ - s->phdr_num = 1; /* PT_NOTE */ - if (s->list.num < UINT16_MAX - 2) { - s->shdr_num = 0; + s->phdr_num = 1; /* Reserve PT_NOTE */ + if (s->list.num <= UINT32_MAX - 1) { s->phdr_num += s->list.num; } else { - /* sh_info of section 0 holds the real number of phdrs */ - s->shdr_num = 1; - - /* the type of shdr->sh_info is uint32_t, so we should avoid overflow */ - if (s->list.num <= UINT32_MAX - 1) { - s->phdr_num += s->list.num; - } else { - s->phdr_num = UINT32_MAX; - } + s->phdr_num = UINT32_MAX; } + /* + * Now that the number of section and program headers is known we + * can calculate the offsets of the headers and data. + */ if (dump_is_64bit(s)) { s->shdr_offset = sizeof(Elf64_Ehdr); s->phdr_offset = s->shdr_offset + sizeof(Elf64_Shdr) * s->shdr_num; diff --git a/include/sysemu/dump-arch.h b/include/sysemu/dump-arch.h index e25b02e99013c75316c8b79da9a3..59bbc9be38c9af0f6181743e2d5c 100644 --- a/include/sysemu/dump-arch.h +++ b/include/sysemu/dump-arch.h @@ -21,6 +21,9 @@ typedef struct ArchDumpInfo { uint32_t page_size; /* The target's page size. If it's variable and * unknown, then this should be the maximum. */ uint64_t phys_base; /* The target's physmem base. */ + void (*arch_sections_add_fn)(DumpState *s); + uint64_t (*arch_sections_write_hdr_fn)(DumpState *s, uint8_t *buff); + int (*arch_sections_write_fn)(DumpState *s, uint8_t *buff); } ArchDumpInfo; struct GuestPhysBlockList; /* memory_mapping.h */ diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h index 9ed811b31331a4c56b7cb851bd02..38ccac7190a253b6c0da3395ac16 100644 --- a/include/sysemu/dump.h +++ b/include/sysemu/dump.h @@ -180,6 +180,9 @@ typedef struct DumpState { hwaddr note_offset; void *elf_section_hdrs; /* Pointer to section header buffer */ + void *elf_section_data; /* Pointer to section data buffer */ + uint64_t elf_section_data_size; /* Size of section data */ + GArray *string_table_buf; /* String table data buffer */ uint8_t *note_buf; /* buffer for notes */ size_t note_buf_offset; /* the writing place in note_buf */
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