From 9c74856af78ac3e8aaa5f8b560e5022d2e6037d1 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 4 Oct 2012 22:48:33 -0400 Subject: [PATCH] dynamic-linked TLS support for everything but dlopen'd libs currently, only i386 is tested. x86_64 and arm should probably work. the necessary relocation types for mips and microblaze have not been added because I don't understand how they're supposed to work, and I'm not even sure if it's defined yet on microblaze. I may be able to reverse engineer the requirements out of gcc/binutils output. --- arch/arm/reloc.h | 17 +++++++- arch/i386/reloc.h | 22 +++++++++- arch/microblaze/reloc.h | 6 ++- arch/mips/reloc.h | 6 ++- arch/x86_64/reloc.h | 17 +++++++- src/ldso/dynlink.c | 96 +++++++++++++++++++++++++---------------- 6 files changed, 121 insertions(+), 43 deletions(-) diff --git a/arch/arm/reloc.h b/arch/arm/reloc.h index 10e89aa3..c37af07b 100644 --- a/arch/arm/reloc.h +++ b/arch/arm/reloc.h @@ -6,7 +6,11 @@ #define IS_COPY(x) ((x)==R_ARM_COPY) #define IS_PLT(x) ((x)==R_ARM_JUMP_SLOT) -static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, size_t sym_size, unsigned char *base_addr, size_t addend) +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_ARM_ABS32: @@ -22,5 +26,16 @@ static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, case R_ARM_COPY: memcpy(reloc_addr, (void *)sym_val, sym_size); break; + case R_ARM_TLS_DTPMOD32: + *reloc_addr = def.dso ? def.dso->tls_id : self->tls_id; + break; + case R_ARM_TLS_DTPOFF32: + *reloc_addr += def.sym->st_value; + break; + case R_ARM_TLS_TPOFF32: + *reloc_addr += def.sym + ? def.sym->st_value - def.dso->tls_offset + : 0 - self->tls_offset; + break; } } diff --git a/arch/i386/reloc.h b/arch/i386/reloc.h index 490113a0..da0bc05d 100644 --- a/arch/i386/reloc.h +++ b/arch/i386/reloc.h @@ -6,7 +6,11 @@ #define IS_COPY(x) ((x)==R_386_COPY) #define IS_PLT(x) ((x)==R_386_JMP_SLOT) -static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, size_t sym_size, unsigned char *base_addr, size_t addend) +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_386_32: @@ -25,5 +29,21 @@ static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, case R_386_COPY: memcpy(reloc_addr, (void *)sym_val, sym_size); break; + case R_386_TLS_DTPMOD32: + *reloc_addr = def.dso ? def.dso->tls_id : self->tls_id; + break; + case R_386_TLS_DTPOFF32: + *reloc_addr = def.sym->st_value; + break; + case R_386_TLS_TPOFF: + *reloc_addr += def.sym + ? def.sym->st_value - def.dso->tls_offset + : 0 - self->tls_offset; + break; + case R_386_TLS_TPOFF32: + *reloc_addr += def.sym + ? def.dso->tls_offset - def.sym->st_value + : self->tls_offset; + break; } } diff --git a/arch/microblaze/reloc.h b/arch/microblaze/reloc.h index 9f04f125..67cb3c2e 100644 --- a/arch/microblaze/reloc.h +++ b/arch/microblaze/reloc.h @@ -6,7 +6,11 @@ #define IS_COPY(x) ((x)==R_MICROBLAZE_COPY) #define IS_PLT(x) ((x)==R_MICROBLAZE_JUMP_SLOT) -static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, size_t sym_size, unsigned char *base_addr, size_t addend) +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_MICROBLAZE_32: diff --git a/arch/mips/reloc.h b/arch/mips/reloc.h index e8925264..785489ed 100644 --- a/arch/mips/reloc.h +++ b/arch/mips/reloc.h @@ -6,7 +6,11 @@ #define IS_COPY(x) ((x)==R_MIPS_COPY) #define IS_PLT(x) 1 -static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, size_t sym_size, unsigned char *base_addr, size_t addend) +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: diff --git a/arch/x86_64/reloc.h b/arch/x86_64/reloc.h index b0bbfb3e..a09df337 100644 --- a/arch/x86_64/reloc.h +++ b/arch/x86_64/reloc.h @@ -7,7 +7,11 @@ #define IS_COPY(x) ((x)==R_X86_64_COPY) #define IS_PLT(x) ((x)==R_X86_64_JUMP_SLOT) -static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, size_t sym_size, unsigned char *base_addr, size_t addend) +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_X86_64_GLOB_DAT: @@ -27,5 +31,16 @@ static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, case R_X86_64_COPY: memcpy(reloc_addr, (void *)sym_val, sym_size); break; + case R_X86_64_TLS_DTPMOD64: + *reloc_addr = def.dso ? def.dso->tls_id : self->tls_id; + break; + case R_X86_64_TLS_DTPOFF64: + *reloc_addr = def.sym->st_value + addend; + break; + case R_X86_64_TLS_TPOFF64: + *reloc_addr = (def.sym + ? def.sym->st_value - def.dso->tls_offset + : 0 - self->tls_offset) + addend; + break; } } diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index 8ff8e696..e09f0715 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -68,11 +68,16 @@ struct dso { char constructed; struct dso **deps; void *tls_image; - size_t tls_len, tls_size, tls_align, tls_id; + size_t tls_len, tls_size, tls_align, tls_id, tls_offset; char *shortname; char buf[]; }; +struct symdef { + Sym *sym; + struct dso *dso; +}; + #include "reloc.h" void __init_ssp(size_t *); @@ -172,13 +177,13 @@ static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso) return 0; } -#define OK_TYPES (1<ghashtab) { gh = gnu_hash(s); if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1; @@ -199,8 +204,9 @@ static void *find_sym(struct dso *dso, const char *s, int need_def) if (sym && (!need_def || sym->st_shndx) && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES) && (1<<(sym->st_info>>4) & OK_BINDS)) { - if (def && sym->st_info>>4 == STB_WEAK) continue; - def = dso->base + sym->st_value; + if (def.sym && sym->st_info>>4 == STB_WEAK) continue; + def.sym = sym; + def.dso = dso; if (sym->st_info>>4 == STB_GLOBAL) break; } } @@ -214,22 +220,20 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri char *strings = dso->strings; Sym *sym; const char *name; - size_t sym_val, sym_size; - size_t *reloc_addr; void *ctx; int type; int sym_index; + struct symdef def; for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) { - reloc_addr = (void *)(base + rel[0]); type = R_TYPE(rel[1]); sym_index = R_SYM(rel[1]); if (sym_index) { sym = syms + sym_index; name = strings + sym->st_name; ctx = IS_COPY(type) ? head->next : head; - sym_val = (size_t)find_sym(ctx, name, IS_PLT(type)); - if (!sym_val && sym->st_info>>4 != STB_WEAK) { + def = find_sym(ctx, name, IS_PLT(type)); + if (!def.sym && sym->st_info>>4 != STB_WEAK) { snprintf(errbuf, sizeof errbuf, "Error relocating %s: %s: symbol not found", dso->name, name); @@ -238,11 +242,14 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri ldso_fail = 1; continue; } - sym_size = sym->st_size; } else { - sym_val = sym_size = 0; + sym = 0; + def.sym = 0; + def.dso = 0; } - do_single_reloc(reloc_addr, type, sym_val, sym_size, base, rel[2]); + do_single_reloc(dso, base, (void *)(base + rel[0]), type, + stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def, + def.sym?(size_t)(def.dso->base+def.sym->st_value):0); } } @@ -816,9 +823,38 @@ void *__dynlink(int argc, char **argv) if (env_preload) load_preload(env_preload); load_deps(app); make_global(app); + + /* Make an initial pass setting up TLS before performing relocs. + * This provides the TP-based offset of each DSO's TLS for + * use in TP-relative relocations. After relocations, we need + * to copy the TLS images again in case they had relocs. */ + tls_size += sizeof(struct pthread) + 4*sizeof(size_t); + __libc.tls_size = tls_size; + __libc.tls_cnt = tls_cnt; + if (tls_cnt) { + struct dso *p; + void *mem = mmap(0, __libc.tls_size, PROT_READ|PROT_WRITE, + MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); + if (mem==MAP_FAILED || + !__install_initial_tls(__copy_tls(mem, tls_cnt))) { + dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n", + argv[0], tls_size); + _exit(127); + } + for (p=head; p; p=p->next) { + if (!p->tls_id) continue; + p->tls_offset = (char *)__pthread_self() + - (char *)__pthread_self()->dtv[p->tls_id]; + } + } + reloc_all(app->next); reloc_all(app); + /* The initial DTV is located at the base of the memory + * allocated for TLS. Repeat copying TLS to pick up relocs. */ + if (tls_cnt) __copy_tls((void *)__pthread_self()->dtv, tls_cnt); + if (ldso_fail) _exit(127); if (ldd_mode) _exit(0); @@ -840,19 +876,6 @@ void *__dynlink(int argc, char **argv) debug.state = 0; _dl_debug_state(); - tls_size += sizeof(struct pthread) + 4*sizeof(size_t); - __libc.tls_size = tls_size; - __libc.tls_cnt = tls_cnt; - if (tls_cnt) { - void *mem = mmap(0, __libc.tls_size, PROT_READ|PROT_WRITE, - MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); - if (mem==MAP_FAILED || - !__install_initial_tls(__copy_tls(mem, tls_cnt))) { - dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n", - argv[0], tls_size); - _exit(127); - } - } if (ssp_used) __init_ssp(auxv); do_init_fini(tail); @@ -933,17 +956,14 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra) size_t i; uint32_t h = 0, gh = 0; Sym *sym; - if (p == RTLD_NEXT) { - for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next); - if (!p) p=head; - void *res = find_sym(p->next, s, 0); - if (!res) goto failed; - return res; - } - if (p == head || p == RTLD_DEFAULT) { - void *res = find_sym(head, s, 0); - if (!res) goto failed; - return res; + if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) { + if (p == RTLD_NEXT) { + for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next); + if (!p) p=head; + } + struct symdef def = find_sym(p->next, s, 0); + if (!def.sym) goto failed; + return def.dso->base + def.sym->st_value; } if (p->ghashtab) { gh = gnu_hash(s); -- 2.25.1