diff --git a/arch/i386/reloc.h b/arch/i386/reloc.h index eaf5aae..95c6022 100644 --- a/arch/i386/reloc.h +++ b/arch/i386/reloc.h @@ -3,31 +3,14 @@ #define LDSO_ARCH "i386" -static int remap_rel(int type) -{ - switch(type) { - case R_386_32: - return REL_SYMBOLIC; - case R_386_PC32: - return REL_OFFSET; - case R_386_GLOB_DAT: - return REL_GOT; - case R_386_JMP_SLOT: - return REL_PLT; - case R_386_RELATIVE: - return REL_RELATIVE; - case R_386_COPY: - return REL_COPY; - case R_386_TLS_DTPMOD32: - return REL_DTPMOD; - case R_386_TLS_DTPOFF32: - return REL_DTPOFF; - case R_386_TLS_TPOFF: - return REL_TPOFF; - case R_386_TLS_TPOFF32: - return REL_TPOFF_NEG; - case R_386_TLS_DESC: - return REL_TLSDESC; - } - return 0; -} +#define REL_SYMBOLIC R_386_32 +#define REL_OFFSET R_386_PC32 +#define REL_GOT R_386_GLOB_DAT +#define REL_PLT R_386_JMP_SLOT +#define REL_RELATIVE R_386_RELATIVE +#define REL_COPY R_386_COPY +#define REL_DTPMOD R_386_TLS_DTPMOD32 +#define REL_DTPOFF R_386_TLS_DTPOFF32 +#define REL_TPOFF R_386_TLS_TPOFF +#define REL_TPOFF_NEG R_386_TLS_TPOFF32 +#define REL_TLSDESC R_386_TLS_DESC diff --git a/arch/mips/reloc.h b/arch/mips/reloc.h index 4b81d32..f77f9d1 100644 --- a/arch/mips/reloc.h +++ b/arch/mips/reloc.h @@ -18,37 +18,12 @@ #define TPOFF_K (-0x7000) -static int remap_rel(int type) -{ - switch(type) { - case R_MIPS_REL32: - return REL_SYM_OR_REL; - case R_MIPS_JUMP_SLOT: - return REL_PLT; - case R_MIPS_COPY: - return REL_COPY; - case R_MIPS_TLS_DTPMOD32: - return REL_DTPMOD; - case R_MIPS_TLS_DTPREL32: - return REL_DTPOFF; - case R_MIPS_TLS_TPREL32: - return REL_TPOFF; - } - return 0; -} - -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] & -t[AT_PAGESZ]); - 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; -} +#define REL_SYM_OR_REL R_MIPS_REL32 +#define REL_PLT R_MIPS_JUMP_SLOT +#define REL_COPY R_MIPS_COPY +#define REL_DTPMOD R_MIPS_TLS_DTPMOD32 +#define REL_DTPOFF R_MIPS_TLS_DTPREL32 +#define REL_TPOFF R_MIPS_TLS_TPREL32 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride); @@ -68,7 +43,7 @@ static void do_arch_relocs(struct dso *this, struct dso *head) got = dynv[i+1]; } i = dyn[DT_MIPS_LOCAL_GOTNO-0x70000000]; - if (this->shortname && !strcmp(this->shortname, "libc.so")) { + if (this->rel_early_relative) { got += sizeof(size_t) * i; } else { for (; i; i--, got+=sizeof(size_t)) @@ -79,11 +54,11 @@ static void do_arch_relocs(struct dso *this, struct dso *head) 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_MIPS_GOT_RELOCS #define NEED_ARCH_RELOCS 1 #define DYNAMIC_IS_RO 1 #define ARCH_SYM_REJECT_UND(s) (!((s)->st_other & STO_MIPS_PLT)) diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index f6ed801..7f19686 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -35,7 +35,7 @@ typedef Elf32_Sym Sym; typedef Elf64_Ehdr Ehdr; typedef Elf64_Phdr Phdr; typedef Elf64_Sym Sym; -#define R_TYPE(x) ((x)&0xffffffff) +#define R_TYPE(x) ((x)&0x7fffffff) #define R_SYM(x) ((x)>>32) #endif @@ -88,6 +88,7 @@ struct dso { volatile int new_dtv_idx, new_tls_idx; struct td_index *td_index; struct dso *fini_next; + int rel_early_relative, rel_update_got; char *shortname; char buf[]; }; @@ -97,9 +98,10 @@ struct symdef { struct dso *dso; }; +/* These enum constants provide unmatchable default values for + * any relocation type the arch does not use. */ enum { - REL_ERR, - REL_SYMBOLIC, + REL_SYMBOLIC = -100, REL_GOT, REL_PLT, REL_RELATIVE, @@ -107,7 +109,6 @@ enum { REL_OFFSET32, REL_COPY, REL_SYM_OR_REL, - REL_TLS, /* everything past here is TLS */ REL_DTPMOD, REL_DTPOFF, REL_TPOFF, @@ -117,6 +118,10 @@ enum { #include "reloc.h" +#define IS_RELATIVE(x) ( \ + (R_TYPE(x) == REL_RELATIVE) || \ + (R_TYPE(x) == REL_SYM_OR_REL && !R_SYM(x)) ) + int __init_tp(void *); void __init_libc(char **, char *); @@ -129,7 +134,8 @@ static struct builtin_tls { } builtin_tls[1]; #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt) -static struct dso *head, *tail, *ldso, *fini_head; +static struct dso ldso; +static struct dso *head, *tail, *fini_head; static char *env_path, *sys_path; static unsigned long long gencnt; static int runtime; @@ -148,9 +154,17 @@ struct debug *_dl_debug_addr = &debug; #define AUX_CNT 38 #define DYN_CNT 34 +static int dl_strcmp(const char *l, const char *r) +{ + for (; *l==*r && *l; l++, r++); + return *(unsigned char *)l - *(unsigned char *)r; +} +#define strcmp(l,r) dl_strcmp(l,r) + static void decode_vec(size_t *v, size_t *a, size_t cnt) { - memset(a, 0, cnt*sizeof(size_t)); + size_t i; + for (i=0; iname, astype); - continue; - } + if (dso->rel_early_relative && IS_RELATIVE(rel[1])) continue; + type = R_TYPE(rel[1]); sym_index = R_SYM(rel[1]); reloc_addr = (void *)(base + rel[0]); if (sym_index) { @@ -324,14 +330,19 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri def.dso = dso; } + int gotplt = (type == REL_GOT || type == REL_PLT); + if (dso->rel_update_got && !gotplt) continue; + addend = stride>2 ? rel[2] - : (1<base+def.sym->st_value : 0; tls_val = def.sym ? def.sym->st_value : 0; switch(type) { + case 0: + break; case REL_OFFSET: addend -= (size_t)reloc_addr; case REL_SYMBOLIC: @@ -395,6 +406,10 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri #endif } break; + default: + error("Error relocating %s: unsupported relocation type %d", + dso->name, type); + continue; } } } @@ -711,22 +726,22 @@ static struct dso *load_library(const char *name, struct dso *needed_by) if (!(reported & mask)) { reported |= mask; dprintf(1, "\t%s => %s (%p)\n", - name, ldso->name, - ldso->base); + name, ldso.name, + ldso.base); } } is_self = 1; } } } - if (!strcmp(name, ldso->name)) is_self = 1; + if (!strcmp(name, ldso.name)) is_self = 1; if (is_self) { - if (!ldso->prev) { - tail->next = ldso; - ldso->prev = tail; - tail = ldso->next ? ldso->next : ldso; + if (!ldso.prev) { + tail->next = &ldso; + ldso.prev = tail; + tail = ldso.next ? ldso.next : &ldso; } - return ldso; + return &ldso; } if (strchr(name, '/')) { pathname = name; @@ -752,13 +767,13 @@ static struct dso *load_library(const char *name, struct dso *needed_by) if (!sys_path) { char *prefix = 0; size_t prefix_len; - if (ldso->name[0]=='/') { + if (ldso.name[0]=='/') { char *s, *t, *z; - for (s=t=z=ldso->name; *s; s++) + for (s=t=z=ldso.name; *s; s++) if (*s=='/') z=t, t=s; - prefix_len = z-ldso->name; + prefix_len = z-ldso.name; if (prefix_len < PATH_MAX) - prefix = ldso->name; + prefix = ldso.name; } if (!prefix) { prefix = ""; @@ -1121,31 +1136,136 @@ static void update_tls_size() tls_align); } -void *__dynlink(int argc, char **argv) +void *__dlstart_c(size_t *sp, size_t *dynv) { - size_t aux[AUX_CNT] = {0}; + size_t i, aux[AUX_CNT], dyn[DYN_CNT]; + + int argc = *sp; + char **argv = (void *)(sp+1); + + for (i=argc+1; argv[i]; i++); + size_t *auxv = (void *)(argv+i+1); + + for (i=0; ip_type == PT_DYNAMIC) { + base = (void *)((size_t)dynv - ph->p_vaddr); + break; + } + } + } + +#ifdef NEED_MIPS_GOT_RELOCS + size_t local_cnt; + size_t *got = (void *)(base + dyn[DT_PLTGOT]); + for (i=0; dynv[i]; i+=2) if (dynv[i]==DT_MIPS_LOCAL_GOTNO) + local_cnt = dynv[i+1]; + for (i=0; ie_phnum; + ldso.phdr = (void *)(base + ehdr->e_phoff); + ldso.phentsize = ehdr->e_phentsize; + ldso.rel_early_relative = 1; + kernel_mapped_dso(&ldso); + decode_dyn(&ldso); + + head = &ldso; + reloc_all(&ldso); + + ldso.relocated = 0; + ldso.rel_update_got = 1; +} + +void *__dls3(size_t *sp, size_t *auxv, size_t *aux) +{ + static struct dso app, vdso; size_t i; - Phdr *phdr; - Ehdr *ehdr; - static struct dso builtin_dsos[3]; - struct dso *const app = builtin_dsos+0; - struct dso *const lib = builtin_dsos+1; - struct dso *const vdso = builtin_dsos+2; char *env_preload=0; size_t vdso_base; - size_t *auxv; + int argc = *sp; + char **argv = (void *)(sp+1); + char **argv_orig = argv; char **envp = argv+argc+1; void *initial_tls; - /* Find aux vector just past environ[] */ - for (i=argc+1; argv[i]; i++) - if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16)) - env_path = argv[i]+16; - else if (!memcmp(argv[i], "LD_PRELOAD=", 11)) - env_preload = argv[i]+11; - auxv = (void *)(argv+i+1); - - decode_vec(auxv, aux, AUX_CNT); + for (i=0; envp[i]; i++) { + if (!memcmp(envp[i], "LD_LIBRARY_PATH=", 16)) + env_path = envp[i]+16; + else if (!memcmp(envp[i], "LD_PRELOAD=", 11)) + env_preload = envp[i]+11; + } /* Only trust user/env if kernel says we're not suid/sgid */ if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID] @@ -1157,54 +1277,36 @@ void *__dynlink(int argc, char **argv) libc.page_size = aux[AT_PAGESZ]; libc.auxv = auxv; - /* If the dynamic linker was invoked as a program itself, AT_BASE - * will not be set. In that case, we assume the base address is - * the start of the page containing the PHDRs; I don't know any - * better approach... */ - if (!aux[AT_BASE]) { - aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE; - aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0; - } - - /* The dynamic linker load address is passed by the kernel - * in the AUX vector, so this is easy. */ - lib->base = (void *)aux[AT_BASE]; - lib->name = lib->shortname = "libc.so"; - lib->global = 1; - ehdr = (void *)lib->base; - lib->phnum = ehdr->e_phnum; - lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff); - lib->phentsize = ehdr->e_phentsize; - kernel_mapped_dso(lib); - decode_dyn(lib); - - if (aux[AT_PHDR]) { + /* If the main program was already loaded by the kernel, + * AT_PHDR will point to some location other than the dynamic + * linker's program headers. */ + if (aux[AT_PHDR] != (size_t)ldso.phdr) { size_t interp_off = 0; size_t tls_image = 0; /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */ - app->phdr = phdr = (void *)aux[AT_PHDR]; - app->phnum = aux[AT_PHNUM]; - app->phentsize = aux[AT_PHENT]; + Phdr *phdr = app.phdr = (void *)aux[AT_PHDR]; + app.phnum = aux[AT_PHNUM]; + app.phentsize = aux[AT_PHENT]; for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) { if (phdr->p_type == PT_PHDR) - app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr); + app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr); else if (phdr->p_type == PT_INTERP) interp_off = (size_t)phdr->p_vaddr; else if (phdr->p_type == PT_TLS) { tls_image = phdr->p_vaddr; - app->tls_len = phdr->p_filesz; - app->tls_size = phdr->p_memsz; - app->tls_align = phdr->p_align; + app.tls_len = phdr->p_filesz; + app.tls_size = phdr->p_memsz; + app.tls_align = phdr->p_align; } } - if (app->tls_size) app->tls_image = (char *)app->base + tls_image; - if (interp_off) lib->name = (char *)app->base + interp_off; + if (app.tls_size) app.tls_image = (char *)app.base + tls_image; + if (interp_off) ldso.name = (char *)app.base + interp_off; if ((aux[0] & (1UL<name = (char *)aux[AT_EXECFN]; + app.name = (char *)aux[AT_EXECFN]; else - app->name = argv[0]; - kernel_mapped_dso(app); + app.name = argv[0]; + kernel_mapped_dso(&app); } else { int fd; char *ldname = argv[0]; @@ -1231,6 +1333,7 @@ void *__dynlink(int argc, char **argv) } argv[-1] = (void *)-1; } + argv[-1] = (void *)(argc - (argv-argv_orig)); if (!argv[0]) { dprintf(2, "musl libc\n" "Version %s\n" @@ -1246,96 +1349,88 @@ void *__dynlink(int argc, char **argv) _exit(1); } runtime = 1; - ehdr = (void *)map_library(fd, app); + Ehdr *ehdr = (void *)map_library(fd, &app); if (!ehdr) { dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]); _exit(1); } runtime = 0; close(fd); - lib->name = ldname; - app->name = argv[0]; - aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry; + ldso.name = ldname; + app.name = argv[0]; + aux[AT_ENTRY] = (size_t)app.base + ehdr->e_entry; /* Find the name that would have been used for the dynamic * linker had ldd not taken its place. */ if (ldd_mode) { - for (i=0; iphnum; i++) { - if (app->phdr[i].p_type == PT_INTERP) - lib->name = (void *)(app->base - + app->phdr[i].p_vaddr); + for (i=0; iname, lib->base); + dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base); } } - if (app->tls_size) { - app->tls_id = tls_cnt = 1; + if (app.tls_size) { + app.tls_id = tls_cnt = 1; #ifdef TLS_ABOVE_TP - app->tls_offset = 0; - tls_offset = app->tls_size - + ( -((uintptr_t)app->tls_image + app->tls_size) - & (app->tls_align-1) ); + app.tls_offset = 0; + tls_offset = app.tls_size + + ( -((uintptr_t)app.tls_image + app.tls_size) + & (app.tls_align-1) ); #else - tls_offset = app->tls_offset = app->tls_size - + ( -((uintptr_t)app->tls_image + app->tls_size) - & (app->tls_align-1) ); + tls_offset = app.tls_offset = app.tls_size + + ( -((uintptr_t)app.tls_image + app.tls_size) + & (app.tls_align-1) ); #endif - tls_align = MAXP2(tls_align, app->tls_align); + tls_align = MAXP2(tls_align, app.tls_align); } - app->global = 1; - decode_dyn(app); + app.global = 1; + decode_dyn(&app); /* Attach to vdso, if provided by the kernel */ if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) { - ehdr = (void *)vdso_base; - vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff); - vdso->phnum = ehdr->e_phnum; - vdso->phentsize = ehdr->e_phentsize; + Ehdr *ehdr = (void *)vdso_base; + Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff); + vdso.phnum = ehdr->e_phnum; + vdso.phentsize = ehdr->e_phentsize; for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) { if (phdr->p_type == PT_DYNAMIC) - vdso->dynv = (void *)(vdso_base + phdr->p_offset); + vdso.dynv = (void *)(vdso_base + phdr->p_offset); if (phdr->p_type == PT_LOAD) - vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset); + vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset); } - vdso->name = ""; - vdso->shortname = "linux-gate.so.1"; - vdso->global = 1; - decode_dyn(vdso); - vdso->prev = lib; - lib->next = vdso; + vdso.name = ""; + vdso.shortname = "linux-gate.so.1"; + vdso.global = 1; + vdso.relocated = 1; + decode_dyn(&vdso); + vdso.prev = &ldso; + ldso.next = &vdso; } - /* Initial dso chain consists only of the app. We temporarily - * append the dynamic linker/libc so we can relocate it, then - * restore the initial chain in preparation for loading third - * party libraries (preload/needed). */ - head = tail = app; - ldso = lib; - app->next = lib; - reloc_all(lib); - app->next = 0; - - /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */ + /* Initial dso chain consists only of the app. */ + head = tail = &app; /* Donate unused parts of app and library mapping to malloc */ - reclaim_gaps(app); - reclaim_gaps(lib); + reclaim_gaps(&app); + reclaim_gaps(&ldso); /* Load preload/needed libraries, add their symbols to the global - * namespace, and perform all remaining relocations. The main - * program must be relocated LAST since it may contain copy - * relocations which depend on libraries' relocations. */ + * namespace, and perform all remaining relocations. */ if (env_preload) load_preload(env_preload); - load_deps(app); - make_global(app); + load_deps(&app); + make_global(&app); #ifndef DYNAMIC_IS_RO - for (i=0; app->dynv[i]; i+=2) - if (app->dynv[i]==DT_DEBUG) - app->dynv[i+1] = (size_t)&debug; + for (i=0; app.dynv[i]; i+=2) + if (app.dynv[i]==DT_DEBUG) + app.dynv[i+1] = (size_t)&debug; #endif - reloc_all(app->next); - reloc_all(app); + /* The main program must be relocated LAST since it may contin + * copy relocations which depend on libraries' relocations. */ + reloc_all(app.next); + reloc_all(&app); update_tls_size(); if (libc.tls_size > sizeof builtin_tls) { @@ -1359,14 +1454,13 @@ void *__dynlink(int argc, char **argv) /* Switch to runtime mode: any further failures in the dynamic * linker are a reportable failure rather than a fatal startup - * error. If the dynamic loader (dlopen) will not be used, free - * all memory used by the dynamic linker. */ + * error. */ runtime = 1; debug.ver = 1; debug.bp = _dl_debug_state; debug.head = head; - debug.base = lib->base; + debug.base = ldso.base; debug.state = 0; _dl_debug_state(); @@ -1375,6 +1469,7 @@ void *__dynlink(int argc, char **argv) errno = 0; do_init_fini(tail); + sp[-1] = (size_t)(argv-1); return (void *)aux[AT_ENTRY]; } diff --git a/src/ldso/i386/start.s b/src/ldso/i386/start.s index c37a1fa..63a20ee 100644 --- a/src/ldso/i386/start.s +++ b/src/ldso/i386/start.s @@ -1,22 +1,17 @@ .text +.hidden _DYNAMIC +.hidden __dlstart_c .global _dlstart _dlstart: xor %ebp,%ebp - pop %edi - mov %esp,%esi + mov %esp,%ebx + push %ebx and $-16,%esp - push %ebp - push %ebp - push %esi - push %edi - call __dynlink - mov %esi,%esp -1: dec %edi - pop %esi - cmp $-1,%esi - jz 1b - inc %edi - push %esi - push %edi - xor %edx,%edx + push %ebx + push %ebx + call 1f +1: addl $_DYNAMIC-1b, (%esp) + push %ebx + call __dlstart_c + mov -4(%ebx),%esp jmp *%eax diff --git a/src/ldso/mips/start.s b/src/ldso/mips/start.s index 0cadbf8..4de1d34 100644 --- a/src/ldso/mips/start.s +++ b/src/ldso/mips/start.s @@ -1,5 +1,5 @@ .hidden _DYNAMIC -.hidden __reloc_self +.hidden __dlstart_c .set noreorder .set nomacro .global _dlstart @@ -11,36 +11,20 @@ _dlstart: nop 2: .gpword 2b .gpword _DYNAMIC - .gpword __reloc_self + .gpword __dlstart_c 1: lw $gp, 0($ra) subu $gp, $ra, $gp - lw $4, 0($sp) - addiu $5, $sp, 4 - lw $6, 4($ra) - addu $6, $6, $gp - addiu $7, $gp, -0x7ff0 - subu $sp, $sp, 16 + move $4, $sp + lw $5, 4($ra) + add $5, $5, $gp lw $25, 8($ra) add $25, $25, $gp - jalr $25 - nop - lw $25, %call16(__dynlink)($gp) - lw $4, 16($sp) - addiu $5, $sp, 20 + move $16, $sp + and $sp, $sp, -8 jalr $25 - nop + subu $sp, $sp, 32 - add $sp, $sp, 16 - li $6, -1 - lw $4, ($sp) -1: lw $5, 4($sp) - bne $5, $6, 2f - nop - addu $sp, $sp, 4 - addu $4, $4, -1 - b 1b - nop -2: sw $4, ($sp) jr $2 + lw $sp, -4($16)