Allocating the header lets us write it at a later time and hence also
allows us to change section and segment table offsets until we
finally write it.
Signed-off-by: Janosch Frank <fran...@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com>
---
dump/dump.c | 127 +++++++++++++++++++++---------------------
include/sysemu/dump.h | 1 +
2 files changed, 64 insertions(+), 64 deletions(-)
diff --git a/dump/dump.c b/dump/dump.c
index 57558a4d4b..8a7ce95610 100644
--- a/dump/dump.c
+++ b/dump/dump.c
@@ -98,6 +98,7 @@ static int dump_cleanup(DumpState *s)
memory_mapping_list_free(&s->list);
close(s->fd);
g_free(s->guest_note);
+ g_free(s->elf_header);
s->guest_note = NULL;
if (s->resume) {
if (s->detached) {
@@ -126,73 +127,49 @@ static int fd_write_vmcore(const void *buf, size_t size,
void *opaque)
return 0;
}
-static void write_elf64_header(DumpState *s, Error **errp)
+static void prepare_elf64_header(DumpState *s)
{
- /*
- * phnum in the elf header is 16 bit, if we have more segments we
- * set phnum to PN_XNUM and write the real number of segments to a
- * special section.
- */
- uint16_t phnum = MIN(s->phdr_num, PN_XNUM);
- Elf64_Ehdr elf_header;
- int ret;
+ uint16_t phnum = s->phdr_num >= PN_XNUM ? PN_XNUM : s->phdr_num;
+ Elf64_Ehdr *elf_header = s->elf_header;
- memset(&elf_header, 0, sizeof(Elf64_Ehdr));
- memcpy(&elf_header, ELFMAG, SELFMAG);
- elf_header.e_ident[EI_CLASS] = ELFCLASS64;
- elf_header.e_ident[EI_DATA] = s->dump_info.d_endian;
- elf_header.e_ident[EI_VERSION] = EV_CURRENT;
- elf_header.e_type = cpu_to_dump16(s, ET_CORE);
- 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, s->phdr_offset);
- elf_header.e_phentsize = cpu_to_dump16(s, sizeof(Elf64_Phdr));
- elf_header.e_phnum = cpu_to_dump16(s, phnum);
+ memcpy(elf_header, ELFMAG, SELFMAG);
+ elf_header->e_ident[EI_CLASS] = ELFCLASS64;
+ elf_header->e_ident[EI_DATA] = s->dump_info.d_endian;
+ elf_header->e_ident[EI_VERSION] = EV_CURRENT;
+ elf_header->e_type = cpu_to_dump16(s, ET_CORE);
+ 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, 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);
- }
-
- ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s);
- if (ret < 0) {
- error_setg_errno(errp, -ret, "dump: failed to write elf header");
+ 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);
}
}
-static void write_elf32_header(DumpState *s, Error **errp)
+static void prepare_elf32_header(DumpState *s)
{
- /*
- * phnum in the elf header is 16 bit, if we have more segments we
- * set phnum to PN_XNUM and write the real number of segments to a
- * special section.
- */
- uint16_t phnum = MIN(s->phdr_num, PN_XNUM);
- Elf32_Ehdr elf_header;
- int ret;
+ uint16_t phnum = s->phdr_num >= PN_XNUM ? PN_XNUM : s->phdr_num;
+ Elf32_Ehdr *elf_header = s->elf_header;
- memset(&elf_header, 0, sizeof(Elf32_Ehdr));
- memcpy(&elf_header, ELFMAG, SELFMAG);
- elf_header.e_ident[EI_CLASS] = ELFCLASS32;
- elf_header.e_ident[EI_DATA] = s->dump_info.d_endian;
- elf_header.e_ident[EI_VERSION] = EV_CURRENT;
- elf_header.e_type = cpu_to_dump16(s, ET_CORE);
- 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, s->phdr_offset);
- elf_header.e_phentsize = cpu_to_dump16(s, sizeof(Elf32_Phdr));
- elf_header.e_phnum = cpu_to_dump16(s, phnum);
+ memcpy(elf_header, ELFMAG, SELFMAG);
+ elf_header->e_ident[EI_CLASS] = ELFCLASS32;
+ elf_header->e_ident[EI_DATA] = s->dump_info.d_endian;
+ elf_header->e_ident[EI_VERSION] = EV_CURRENT;
+ elf_header->e_type = cpu_to_dump16(s, ET_CORE);
+ 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, 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);
- }
-
- ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s);
- if (ret < 0) {
- error_setg_errno(errp, -ret, "dump: failed to write elf header");
+ 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);
}
}
@@ -528,6 +505,26 @@ static void write_elf_notes(DumpState *s, Error **errp)
}
}
+static void prepare_elf_header(DumpState *s)
+{
+ if (dump_is_64bit(s)) {
+ prepare_elf64_header(s);
+ } else {
+ prepare_elf32_header(s);
+ }
+}
+
+static void write_elf_header(DumpState *s, Error **errp)
+{
+ size_t size = dump_is_64bit(s) ? sizeof(Elf64_Ehdr) : sizeof(Elf32_Ehdr);
+ int ret;
+
+ ret = fd_write_vmcore(s->elf_header, size, s);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "dump: failed to write elf header");
+ }
+}
+
/* write elf header, PT_NOTE and elf note to vmcore. */
static void dump_begin(DumpState *s, Error **errp)
{
@@ -557,12 +554,11 @@ static void dump_begin(DumpState *s, Error **errp)
* vmcore.
*/
- /* write elf header to vmcore */
- if (dump_is_64bit(s)) {
- write_elf64_header(s, errp);
- } else {
- write_elf32_header(s, errp);
- }
+ /* Write elf header to buffer */
+ prepare_elf_header(s);
+
+ /* Start to write stuff into file descriptor */
+ write_elf_header(s, errp);
if (*errp) {
return;
}
@@ -1679,6 +1675,9 @@ static void dump_init(DumpState *s, int fd, bool
has_format,
goto cleanup;
}
+ s->elf_header = g_malloc0(dump_is_64bit(s) ?
+ sizeof(Elf64_Ehdr) : sizeof(Elf32_Ehdr));
+
/*
* The goal of this block is to (a) update the previously guessed
* phys_base, (b) copy the guest note out of the guest.
diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h
index 24ebb02660..7f9a848573 100644
--- a/include/sysemu/dump.h
+++ b/include/sysemu/dump.h
@@ -171,6 +171,7 @@ typedef struct DumpState {
int64_t begin; /* Start address of the chunk we want to dump */
int64_t length; /* Length of the dump we want to dump */
+ void *elf_header;
uint8_t *note_buf; /* buffer for notes */
size_t note_buf_offset; /* the writing place in note_buf */
uint32_t nr_cpus; /* number of guest's cpu */
--
2.34.1
