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Collection of small llvm fixes #1305

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Merged
joe-lawrence merged 3 commits into from
Oct 4, 2022
Merged

Collection of small llvm fixes #1305

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5f6c596
kpatch-build: for clang, use .strtab if no .shstrtab
swine Sep 27, 2022
3704057
create-diff-object: ignore clang's .llvm_addrsig sections
swine Sep 27, 2022
85781b7
create-diff-object: ignore .llvm.* sections
swine Sep 27, 2022
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4 changes: 3 additions & 1 deletion kpatch-build/create-diff-object.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2717,7 +2717,9 @@ static void kpatch_mark_ignored_sections(struct kpatch_elf *kelf)
/* Ignore any discarded sections */
list_for_each_entry(sec, &kelf->sections, list) {
if (!strncmp(sec->name, ".discard", 8) ||
!strncmp(sec->name, ".rela.discard", 13))
!strncmp(sec->name, ".rela.discard", 13) ||
!strncmp(sec->name, ".llvm_addrsig", 13) ||
!strncmp(sec->name, ".llvm.", 6))
sec->ignore = 1;
}

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33 changes: 29 additions & 4 deletions kpatch-build/kpatch-elf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -607,7 +607,7 @@ void kpatch_create_shstrtab(struct kpatch_elf *kelf)

shstrtab = find_section_by_name(&kelf->sections, ".shstrtab");
if (!shstrtab)
ERROR("find_section_by_name");
return;

/* determine size of string table */
size = 1; /* for initial NULL terminator */
Expand Down Expand Up @@ -648,7 +648,7 @@ void kpatch_create_shstrtab(struct kpatch_elf *kelf)

void kpatch_create_strtab(struct kpatch_elf *kelf)
{
struct section *strtab;
struct section *strtab, *shstrtab;
struct symbol *sym;
size_t size = 0, offset = 0, len;
char *buf;
Expand All @@ -657,13 +657,24 @@ void kpatch_create_strtab(struct kpatch_elf *kelf)
if (!strtab)
ERROR("find_section_by_name");

shstrtab = find_section_by_name(&kelf->sections, ".shstrtab");

/* determine size of string table */
list_for_each_entry(sym, &kelf->symbols, list) {
if (sym->type == STT_SECTION)
continue;
size += strlen(sym->name) + 1; /* include NULL terminator */
}

/* and when covering for missing .shstrtab ... */
if (!shstrtab) {
/* factor out into common (sh)strtab feeder */
struct section *sec;

list_for_each_entry(sec, &kelf->sections, list)
size += strlen(sec->name) + 1; /* include NULL terminator */
}

/* allocate data buffer */
buf = malloc(size);
if (!buf)
Expand All @@ -682,8 +693,20 @@ void kpatch_create_strtab(struct kpatch_elf *kelf)
offset += len;
}

if (!shstrtab) {
struct section *sec;

/* populate string table and link with section header */
list_for_each_entry(sec, &kelf->sections, list) {
len = strlen(sec->name) + 1;
sec->sh.sh_name = (unsigned int)offset;
memcpy(buf + offset, sec->name, len);
offset += len;
}
}

if (offset != size)
ERROR("shstrtab size mismatch");
ERROR("strtab size mismatch");

strtab->data->d_buf = buf;
strtab->data->d_size = size;
Expand Down Expand Up @@ -928,7 +951,9 @@ void kpatch_write_output_elf(struct kpatch_elf *kelf, Elf *elf, char *outfile,

shstrtab = find_section_by_name(&kelf->sections, ".shstrtab");
if (!shstrtab)
ERROR("missing .shstrtab section");
shstrtab = find_section_by_name(&kelf->sections, ".strtab");
if (!shstrtab)
ERROR("missing .shstrtab, .strtab sections");

ehout.e_shstrndx = (unsigned short)shstrtab->index;

Expand Down