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bsd-user: elfload: simplify bswap a bit.
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Reduce the number of ifdefs by always calling the swapping routine, but
making them empty when swapping isn't needed.

Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
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@bsdimp
bsdimp committed Sep 10, 2021
1 parent d8fcdad commit b62f790
Showing 1 changed file with 47 additions and 50 deletions.
97 changes: 47 additions & 50 deletions bsd-user/elfload.c
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Original file line number Diff line number Diff line change
Expand Up @@ -67,51 +67,59 @@

static inline void memcpy_fromfs(void *to, const void *from, unsigned long n)
{
memcpy(to, from, n);
memcpy(to, from, n);
}

#ifdef BSWAP_NEEDED
static void bswap_ehdr(struct elfhdr *ehdr)
{
bswap16s(&ehdr->e_type); /* Object file type */
bswap16s(&ehdr->e_type); /* Object file type */
bswap16s(&ehdr->e_machine); /* Architecture */
bswap32s(&ehdr->e_version); /* Object file version */
bswaptls(&ehdr->e_entry); /* Entry point virtual address */
bswaptls(&ehdr->e_phoff); /* Program header table file offset */
bswaptls(&ehdr->e_shoff); /* Section header table file offset */
bswap32s(&ehdr->e_flags); /* Processor-specific flags */
bswap16s(&ehdr->e_ehsize); /* ELF header size in bytes */
bswap16s(&ehdr->e_phentsize); /* Program header table entry size */
bswap16s(&ehdr->e_phentsize); /* Program header table entry size */
bswap16s(&ehdr->e_phnum); /* Program header table entry count */
bswap16s(&ehdr->e_shentsize); /* Section header table entry size */
bswap16s(&ehdr->e_shentsize); /* Section header table entry size */
bswap16s(&ehdr->e_shnum); /* Section header table entry count */
bswap16s(&ehdr->e_shstrndx); /* Section header string table index */
bswap16s(&ehdr->e_shstrndx); /* Section header string table index */
}

static void bswap_phdr(struct elf_phdr *phdr)
static void bswap_phdr(struct elf_phdr *phdr, int phnum)
{
bswap32s(&phdr->p_type); /* Segment type */
bswaptls(&phdr->p_offset); /* Segment file offset */
bswaptls(&phdr->p_vaddr); /* Segment virtual address */
bswaptls(&phdr->p_paddr); /* Segment physical address */
bswaptls(&phdr->p_filesz); /* Segment size in file */
bswaptls(&phdr->p_memsz); /* Segment size in memory */
bswap32s(&phdr->p_flags); /* Segment flags */
bswaptls(&phdr->p_align); /* Segment alignment */
int i;

for (i = 0; i < phnum; i++, phdr++) {
bswap32s(&phdr->p_type); /* Segment type */
bswap32s(&phdr->p_flags); /* Segment flags */
bswaptls(&phdr->p_offset); /* Segment file offset */
bswaptls(&phdr->p_vaddr); /* Segment virtual address */
bswaptls(&phdr->p_paddr); /* Segment physical address */
bswaptls(&phdr->p_filesz); /* Segment size in file */
bswaptls(&phdr->p_memsz); /* Segment size in memory */
bswaptls(&phdr->p_align); /* Segment alignment */
}
}

static void bswap_shdr(struct elf_shdr *shdr)
static void bswap_shdr(struct elf_shdr *shdr, int shnum)
{
bswap32s(&shdr->sh_name);
bswap32s(&shdr->sh_type);
bswaptls(&shdr->sh_flags);
bswaptls(&shdr->sh_addr);
bswaptls(&shdr->sh_offset);
bswaptls(&shdr->sh_size);
bswap32s(&shdr->sh_link);
bswap32s(&shdr->sh_info);
bswaptls(&shdr->sh_addralign);
bswaptls(&shdr->sh_entsize);
int i;

for (i = 0; i < shnum; i++, shdr++) {
bswap32s(&shdr->sh_name);
bswap32s(&shdr->sh_type);
bswaptls(&shdr->sh_flags);
bswaptls(&shdr->sh_addr);
bswaptls(&shdr->sh_offset);
bswaptls(&shdr->sh_size);
bswap32s(&shdr->sh_link);
bswap32s(&shdr->sh_info);
bswaptls(&shdr->sh_addralign);
bswaptls(&shdr->sh_entsize);
}
}

static void bswap_sym(struct elf_sym *sym)
Expand All @@ -121,7 +129,15 @@ static void bswap_sym(struct elf_sym *sym)
bswaptls(&sym->st_size);
bswap16s(&sym->st_shndx);
}
#endif

#else /* ! BSWAP_NEEDED */

static void bswap_ehdr(struct elfhdr *ehdr) { }
static void bswap_phdr(struct elf_phdr *phdr, int phnum) { }
static void bswap_shdr(struct elf_shdr *shdr, int shnum) { }
static void bswap_sym(struct elf_sym *sym) { }

#endif /* ! BSWAP_NEEDED */

/*
* 'copy_elf_strings()' copies argument/envelope strings from user
Expand Down Expand Up @@ -367,9 +383,7 @@ static abi_ulong load_elf_interp(struct elfhdr *interp_elf_ex,
last_bss = 0;
error = 0;

#ifdef BSWAP_NEEDED
bswap_ehdr(interp_elf_ex);
#endif
/* First of all, some simple consistency checks */
if ((interp_elf_ex->e_type != ET_EXEC &&
interp_elf_ex->e_type != ET_DYN) ||
Expand Down Expand Up @@ -410,12 +424,7 @@ static abi_ulong load_elf_interp(struct elfhdr *interp_elf_ex,
free(elf_phdata);
return retval;
}
#ifdef BSWAP_NEEDED
eppnt = elf_phdata;
for (i = 0; i<interp_elf_ex->e_phnum; i++, eppnt++) {
bswap_phdr(eppnt);
}
#endif
bswap_phdr(elf_phdata, interp_elf_ex->e_phnum);

if (interp_elf_ex->e_type == ET_DYN) {
/* in order to avoid hardcoding the interpreter load
Expand Down Expand Up @@ -560,19 +569,15 @@ static void load_symbols(struct elfhdr *hdr, int fd)
for (i = 0; i < hdr->e_shnum; i++) {
if (read(fd, &sechdr, sizeof(sechdr)) != sizeof(sechdr))
return;
#ifdef BSWAP_NEEDED
bswap_shdr(&sechdr);
#endif
bswap_shdr(&sechdr, 1);
if (sechdr.sh_type == SHT_SYMTAB) {
symtab = sechdr;
lseek(fd, hdr->e_shoff
+ sizeof(sechdr) * sechdr.sh_link, SEEK_SET);
if (read(fd, &strtab, sizeof(strtab))
!= sizeof(strtab))
return;
#ifdef BSWAP_NEEDED
bswap_shdr(&strtab);
#endif
bswap_shdr(&strtab, 1);
goto found;
}
}
Expand Down Expand Up @@ -605,9 +610,7 @@ static void load_symbols(struct elfhdr *hdr, int fd)

i = 0;
while (i < nsyms) {
#ifdef BSWAP_NEEDED
bswap_sym(syms + i);
#endif
// Throw away entries which we do not need.
if (syms[i].st_shndx == SHN_UNDEF ||
syms[i].st_shndx >= SHN_LORESERVE ||
Expand Down Expand Up @@ -679,9 +682,7 @@ int load_elf_binary(struct bsd_binprm *bprm, struct target_pt_regs *regs,
load_addr = 0;
load_bias = 0;
elf_ex = *((struct elfhdr *) bprm->buf); /* exec-header */
#ifdef BSWAP_NEEDED
bswap_ehdr(&elf_ex);
#endif

/* First of all, some simple consistency checks */
if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
Expand Down Expand Up @@ -715,12 +716,8 @@ int load_elf_binary(struct bsd_binprm *bprm, struct target_pt_regs *regs,
return -errno;
}

#ifdef BSWAP_NEEDED
elf_ppnt = elf_phdata;
for (i = 0; i < elf_ex.e_phnum; i++, elf_ppnt++) {
bswap_phdr(elf_ppnt);
}
#endif
bswap_phdr(elf_phdata, elf_ex.e_phnum);

elf_ppnt = elf_phdata;

elf_bss = 0;
Expand Down

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