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[PATCH v3 5/9] dump: Add more offset variables
From: |
Janosch Frank |
Subject: |
[PATCH v3 5/9] dump: Add more offset variables |
Date: |
Wed, 30 Mar 2022 12:35:59 +0000 |
Offset calculations are easy enough to get wrong. Let's add a few
variables to make moving around elf headers and data sections easier.
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
dump/dump.c | 35 +++++++++++++++--------------------
include/sysemu/dump.h | 4 ++++
2 files changed, 19 insertions(+), 20 deletions(-)
diff --git a/dump/dump.c b/dump/dump.c
index bdff651da4..4be4dcab24 100644
--- a/dump/dump.c
+++ b/dump/dump.c
@@ -137,13 +137,11 @@ static void write_elf64_header(DumpState *s, Error **errp)
elf_header.e_machine = cpu_to_dump16(s, s->dump_info.d_machine);
elf_header.e_version = cpu_to_dump32(s, EV_CURRENT);
elf_header.e_ehsize = cpu_to_dump16(s, sizeof(elf_header));
- elf_header.e_phoff = cpu_to_dump64(s, sizeof(Elf64_Ehdr));
+ 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) {
- uint64_t shoff = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) * s->phdr_num;
-
- elf_header.e_shoff = cpu_to_dump64(s, shoff);
+ 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);
}
@@ -169,13 +167,11 @@ static void write_elf32_header(DumpState *s, Error **errp)
elf_header.e_machine = cpu_to_dump16(s, s->dump_info.d_machine);
elf_header.e_version = cpu_to_dump32(s, EV_CURRENT);
elf_header.e_ehsize = cpu_to_dump16(s, sizeof(elf_header));
- elf_header.e_phoff = cpu_to_dump32(s, sizeof(Elf32_Ehdr));
+ 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) {
- uint32_t shoff = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr) * s->phdr_num;
-
- elf_header.e_shoff = cpu_to_dump32(s, shoff);
+ 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);
}
@@ -238,12 +234,11 @@ static void write_elf32_load(DumpState *s, MemoryMapping
*memory_mapping,
static void write_elf64_note(DumpState *s, Error **errp)
{
Elf64_Phdr phdr;
- hwaddr begin = s->memory_offset - s->note_size;
int ret;
memset(&phdr, 0, sizeof(Elf64_Phdr));
phdr.p_type = cpu_to_dump32(s, PT_NOTE);
- phdr.p_offset = cpu_to_dump64(s, begin);
+ phdr.p_offset = cpu_to_dump64(s, s->note_offset);
phdr.p_paddr = 0;
phdr.p_filesz = cpu_to_dump64(s, s->note_size);
phdr.p_memsz = cpu_to_dump64(s, s->note_size);
@@ -303,13 +298,12 @@ static void write_elf64_notes(WriteCoreDumpFunction f,
DumpState *s,
static void write_elf32_note(DumpState *s, Error **errp)
{
- hwaddr begin = s->memory_offset - s->note_size;
Elf32_Phdr phdr;
int ret;
memset(&phdr, 0, sizeof(Elf32_Phdr));
phdr.p_type = cpu_to_dump32(s, PT_NOTE);
- phdr.p_offset = cpu_to_dump32(s, begin);
+ phdr.p_offset = cpu_to_dump32(s, s->note_offset);
phdr.p_paddr = 0;
phdr.p_filesz = cpu_to_dump32(s, s->note_size);
phdr.p_memsz = cpu_to_dump32(s, s->note_size);
@@ -1808,15 +1802,16 @@ static void dump_init(DumpState *s, int fd, bool
has_format,
}
if (s->dump_info.d_class == ELFCLASS64) {
- s->memory_offset = sizeof(Elf64_Ehdr) +
- sizeof(Elf64_Phdr) * s->phdr_num +
- sizeof(Elf64_Shdr) * s->shdr_num +
- s->note_size;
+ s->phdr_offset = sizeof(Elf64_Ehdr);
+ s->shdr_offset = s->phdr_offset + sizeof(Elf64_Phdr) * s->phdr_num;
+ s->note_offset = s->shdr_offset + sizeof(Elf64_Shdr) * s->shdr_num;
+ s->memory_offset = s->note_offset + s->note_size;
} else {
- s->memory_offset = sizeof(Elf32_Ehdr) +
- sizeof(Elf32_Phdr) * s->phdr_num +
- sizeof(Elf32_Shdr) * s->shdr_num +
- s->note_size;
+
+ s->phdr_offset = sizeof(Elf32_Ehdr);
+ s->shdr_offset = s->phdr_offset + sizeof(Elf32_Phdr) * s->phdr_num;
+ s->note_offset = s->shdr_offset + sizeof(Elf32_Shdr) * s->shdr_num;
+ s->memory_offset = s->note_offset + s->note_size;
}
return;
diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h
index 19458bffbd..ffc2ea1072 100644
--- a/include/sysemu/dump.h
+++ b/include/sysemu/dump.h
@@ -159,6 +159,10 @@ typedef struct DumpState {
bool resume;
bool detached;
ssize_t note_size;
+ hwaddr shdr_offset;
+ hwaddr phdr_offset;
+ hwaddr section_offset;
+ hwaddr note_offset;
hwaddr memory_offset;
int fd;
--
2.32.0
[PATCH v3 6/9] dump: Introduce dump_is_64bit() helper function, Janosch Frank, 2022/03/30
[PATCH v3 9/9] dump: Consolidate elf note function, Janosch Frank, 2022/03/30
[PATCH v3 8/9] dump: Cleanup dump_begin write functions, Janosch Frank, 2022/03/30