musl/arch/mips/reloc.h
Rich Felker f389c4984a make the dynamic linker find its path file relative to its own location
prior to this change, using a non-default syslibdir was impractical on
systems where the ordinary library paths contain musl-incompatible
library files. the file containing search paths was always taken from
/etc, which would either correspond to a system-wide musl
installation, or fail to exist at all, resulting in searching of the
default library path.

the new search strategy is safe even for suid programs because the
pathname used comes from the PT_INTERP header of the program being
run, rather than any external input.

as part of this change, I have also begun differentiating the names of
arch variants that differ by endianness or floating point calling
convention. the corresponding changes in the build system and and gcc
wrapper script (to use an alternate dynamic linker name) for these
configurations have not yet been made.
2013-07-18 19:29:44 -04:00

96 lines
2.4 KiB
C

#include <string.h>
#include <elf.h>
#include <endian.h>
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define ENDIAN_SUFFIX "el"
#else
#define ENDIAN_SUFFIX ""
#endif
#define LDSO_ARCH "mips" ENDIAN_SUFFIX
#define IS_COPY(x) ((x)==R_MIPS_COPY)
#define IS_PLT(x) 1
static inline void do_single_reloc(
struct dso *self, unsigned char *base_addr,
size_t *reloc_addr, int type, size_t addend,
Sym *sym, size_t sym_size,
struct symdef def, size_t sym_val)
{
switch(type) {
case R_MIPS_JUMP_SLOT:
*reloc_addr = sym_val;
break;
case R_MIPS_REL32:
if (sym_val) *reloc_addr += sym_val;
else *reloc_addr += (size_t)base_addr;
break;
case R_MIPS_COPY:
memcpy(reloc_addr, (void *)sym_val, sym_size);
break;
case R_MIPS_TLS_DTPMOD32:
*reloc_addr = def.dso ? def.dso->tls_id : self->tls_id;
break;
case R_MIPS_TLS_DTPREL32:
*reloc_addr += def.sym->st_value;
break;
case R_MIPS_TLS_TPREL32:
*reloc_addr += def.sym
? def.sym->st_value + def.dso->tls_offset - 0x7000
: self->tls_offset - 0x7000;
break;
}
}
void __reloc_self(int c, size_t *a, size_t *dynv, size_t *got)
{
char *base;
size_t t[20], n;
for (a+=c+1; *a; a++);
for (a++; *a; a+=2) if (*a<20) t[*a] = a[1];
base = (char *)t[AT_BASE];
if (!base) base = (char *)(t[AT_PHDR] & -4096);
for (a=dynv; *a; a+=2) if (*a-0x70000000UL<20) t[*a&31] = a[1];
n = t[DT_MIPS_LOCAL_GOTNO - 0x70000000];
for (a=got; n; a++, n--) *a += (size_t)base;
}
static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride);
static void do_arch_relocs(struct dso *this, struct dso *head)
{
unsigned char *base = this->base;
size_t *dynv = this->dynv;
size_t dyn[20] = {0};
size_t i;
size_t rel[2], got=0;
Sym *sym;
for (i=0; dynv[i]; i+=2) {
if (dynv[i]-0x70000000UL<20)
dyn[dynv[i]&31] = dynv[i+1];
else if (dynv[i] == DT_PLTGOT)
got = dynv[i+1];
}
i = dyn[DT_MIPS_LOCAL_GOTNO-0x70000000];
if (this->shortname && !strcmp(this->shortname, "libc.so")) {
got += sizeof(size_t) * i;
} else {
for (; i; i--, got+=sizeof(size_t))
*(size_t *)(base+got) += (size_t)base;
}
sym = this->syms + dyn[DT_MIPS_GOTSYM-0x70000000];
i = dyn[DT_MIPS_SYMTABNO-0x70000000] - dyn[DT_MIPS_GOTSYM-0x70000000];
for (; i; i--, got+=sizeof(size_t), sym++) {
rel[0] = got;
rel[1] = sym-this->syms << 8 | R_MIPS_JUMP_SLOT;
*(size_t *)(base+got) = 0;
do_relocs(this, rel, sizeof rel, 2);
}
}
#define NEED_ARCH_RELOCS 1
#define DYNAMIC_IS_RO 1