X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fldso%2Fdynlink.c;h=d7d6800238fea88d161ebdc2ac0ea8dc0b3cf167;hp=02c880b4b87ecddbc65ab5221847157b84d49e15;hb=2bd05a4fc26c297754f7ee5745a1c3b072a44b7d;hpb=4027f4e8f948c26be5e61c774f9f9ce9af8942b5 diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index 02c880b4..d7d68002 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -20,9 +20,7 @@ static int errflag; static char errbuf[128]; -#ifdef __PIC__ - -#include "reloc.h" +#ifdef SHARED #if ULONG_MAX == 0xffffffff typedef Elf32_Ehdr Ehdr; @@ -55,18 +53,22 @@ struct dso { int refcnt; Sym *syms; uint32_t *hashtab; + uint32_t *ghashtab; char *strings; unsigned char *map; size_t map_len; dev_t dev; ino_t ino; - char global; + signed char global; char relocated; char constructed; struct dso **deps; + char *shortname; char buf[]; }; +#include "reloc.h" + void __init_ssp(size_t *); static struct dso *head, *tail, *libc; @@ -74,6 +76,8 @@ static char *env_path, *sys_path, *r_path; static int rtld_used; static int ssp_used; static int runtime; +static int ldd_mode; +static int ldso_fail; static jmp_buf rtld_fail; static pthread_rwlock_t lock; static struct debug debug; @@ -92,7 +96,15 @@ static void decode_vec(size_t *v, size_t *a, size_t cnt) } } -static uint32_t hash(const char *s0) +static int search_vec(size_t *v, size_t *r, size_t key) +{ + for (; v[0]!=key; v+=2) + if (!v[0]) return 0; + *r = v[1]; + return 1; +} + +static uint32_t sysv_hash(const char *s0) { const unsigned char *s = (void *)s0; uint_fast32_t h = 0; @@ -103,9 +115,21 @@ static uint32_t hash(const char *s0) return h & 0xfffffff; } -static Sym *lookup(const char *s, uint32_t h, Sym *syms, uint32_t *hashtab, char *strings) +static uint32_t gnu_hash(const char *s0) +{ + const unsigned char *s = (void *)s0; + uint_fast32_t h = 5381; + for (; *s; s++) + h = h*33 + *s; + return h; +} + +static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso) { size_t i; + Sym *syms = dso->syms; + uint32_t *hashtab = dso->hashtab; + char *strings = dso->strings; for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) { if (!strcmp(s, strings+syms[i].st_name)) return syms+i; @@ -113,20 +137,61 @@ static Sym *lookup(const char *s, uint32_t h, Sym *syms, uint32_t *hashtab, char return 0; } +static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso) +{ + Sym *sym; + char *strings; + uint32_t *hashtab = dso->ghashtab; + uint32_t nbuckets = hashtab[0]; + uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4); + uint32_t h2; + uint32_t *hashval; + uint32_t n = buckets[h1 % nbuckets]; + + if (!n) return 0; + + strings = dso->strings; + sym = dso->syms + n; + hashval = buckets + nbuckets + (n - hashtab[1]); + + for (h1 |= 1; ; sym++) { + h2 = *hashval++; + if ((h1 == (h2|1)) && !strcmp(s, strings + sym->st_name)) + return sym; + if (h2 & 1) break; + } + + return 0; +} + #define OK_TYPES (1<ghashtab) { + gh = gnu_hash(s); + if (gh == 0xf9040207 && !strcmp(s, "dlopen")) rtld_used = 1; + if (gh == 0xf4dc4ae && !strcmp(s, "dlsym")) rtld_used = 1; + if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1; + } else { + h = sysv_hash(s); + if (h == 0x6b366be && !strcmp(s, "dlopen")) rtld_used = 1; + if (h == 0x6b3afd && !strcmp(s, "dlsym")) rtld_used = 1; + if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1; + } for (; dso; dso=dso->next) { Sym *sym; if (!dso->global) continue; - sym = lookup(s, h, dso->syms, dso->hashtab, dso->strings); + if (dso->ghashtab) { + if (!gh) gh = gnu_hash(s); + sym = gnu_lookup(s, gh, dso); + } else { + if (!h) h = sysv_hash(s); + sym = sysv_lookup(s, h, dso); + } if (sym && (!need_def || sym->st_shndx) && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES) && (1<<(sym->st_info>>4) & OK_BINDS)) { @@ -138,8 +203,11 @@ static void *find_sym(struct dso *dso, const char *s, int need_def) return def; } -static void do_relocs(unsigned char *base, size_t *rel, size_t rel_size, size_t stride, Sym *syms, char *strings, struct dso *dso) +static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride) { + unsigned char *base = dso->base; + Sym *syms = dso->syms; + char *strings = dso->strings; Sym *sym; const char *name; size_t sym_val, sym_size; @@ -155,7 +223,7 @@ static void do_relocs(unsigned char *base, size_t *rel, size_t rel_size, size_t if (sym_index) { sym = syms + sym_index; name = strings + sym->st_name; - ctx = IS_COPY(type) ? dso->next : dso; + 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) { snprintf(errbuf, sizeof errbuf, @@ -163,9 +231,12 @@ static void do_relocs(unsigned char *base, size_t *rel, size_t rel_size, size_t dso->name, name); if (runtime) longjmp(rtld_fail, 1); dprintf(2, "%s\n", errbuf); - _exit(127); + ldso_fail = 1; + continue; } sym_size = sym->st_size; + } else { + sym_val = sym_size = 0; } do_single_reloc(reloc_addr, type, sym_val, sym_size, base, rel[2]); } @@ -266,23 +337,20 @@ static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dy prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) | ((ph->p_flags&PF_W) ? PROT_WRITE: 0) | ((ph->p_flags&PF_X) ? PROT_EXEC : 0)); - if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED) { - munmap(map, map_len); - return 0; - } + if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED) + goto error; if (ph->p_memsz > ph->p_filesz) { size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz; size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE; memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1); - if (pgbrk-(size_t)base < this_max && mmap((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) { - munmap(map, map_len); - return 0; - } + if (pgbrk-(size_t)base < this_max && mmap((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) + goto error; } } for (i=0; ((size_t *)(base+dyn))[i]; i+=2) if (((size_t *)(base+dyn))[i]==DT_TEXTREL) { - mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC); + if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0) + goto error; break; } if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff), @@ -291,11 +359,13 @@ static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dy *basep = base; *dynp = dyn; return map; +error: + munmap(map, map_len); + return 0; } -static int path_open(const char *name, const char *search) +static int path_open(const char *name, const char *search, char *buf, size_t buf_size) { - char buf[2*NAME_MAX+2]; const char *s=search, *z; int l, fd; for (;;) { @@ -303,7 +373,7 @@ static int path_open(const char *name, const char *search) if (!*s) return -1; z = strchr(s, ':'); l = z ? z-s : strlen(s); - snprintf(buf, sizeof buf, "%.*s/%s", l, s, name); + snprintf(buf, buf_size, "%.*s/%s", l, s, name); if ((fd = open(buf, O_RDONLY))>=0) return fd; s += l; } @@ -314,12 +384,17 @@ static void decode_dyn(struct dso *p) size_t dyn[DYN_CNT] = {0}; decode_vec(p->dynv, dyn, DYN_CNT); p->syms = (void *)(p->base + dyn[DT_SYMTAB]); - p->hashtab = (void *)(p->base + dyn[DT_HASH]); p->strings = (void *)(p->base + dyn[DT_STRTAB]); + if (dyn[0]&(1<hashtab = (void *)(p->base + dyn[DT_HASH]); + if (search_vec(p->dynv, dyn, DT_GNU_HASH)) + p->ghashtab = (void *)(p->base + *dyn); } static struct dso *load_library(const char *name) { + char buf[2*NAME_MAX+2]; + const char *pathname; unsigned char *base, *map; size_t dyno, map_len; struct dso *p; @@ -344,20 +419,21 @@ static struct dso *load_library(const char *name) } } } - /* Search for the name to see if it's already loaded */ - for (p=head->next; p; p=p->next) { - if (!strcmp(p->name, name)) { - p->refcnt++; - return p; - } - } if (strchr(name, '/')) { + pathname = name; fd = open(name, O_RDONLY); } else { + /* Search for the name to see if it's already loaded */ + for (p=head->next; p; p=p->next) { + if (p->shortname && !strcmp(p->shortname, name)) { + p->refcnt++; + return p; + } + } if (strlen(name) > NAME_MAX) return 0; fd = -1; - if (r_path) fd = path_open(name, r_path); - if (fd < 0 && env_path) fd = path_open(name, env_path); + if (r_path) fd = path_open(name, r_path, buf, sizeof buf); + if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf); if (fd < 0) { if (!sys_path) { FILE *f = fopen(ETC_LDSO_PATH, "r"); @@ -367,9 +443,10 @@ static struct dso *load_library(const char *name) fclose(f); } } - if (sys_path) fd = path_open(name, sys_path); - else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib"); + if (sys_path) fd = path_open(name, sys_path, buf, sizeof buf); + else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib", buf, sizeof buf); } + pathname = buf; } if (fd < 0) return 0; if (fstat(fd, &st) < 0) { @@ -378,6 +455,10 @@ static struct dso *load_library(const char *name) } for (p=head->next; p; p=p->next) { if (p->dev == st.st_dev && p->ino == st.st_ino) { + /* If this library was previously loaded with a + * pathname but a search found the same inode, + * setup its shortname so it can be found by name. */ + if (!p->shortname) p->shortname = strrchr(p->name, '/')+1; close(fd); p->refcnt++; return p; @@ -386,7 +467,7 @@ static struct dso *load_library(const char *name) map = map_library(fd, &map_len, &base, &dyno); close(fd); if (!map) return 0; - p = calloc(1, sizeof *p + strlen(name) + 1); + p = calloc(1, sizeof *p + strlen(pathname) + 1); if (!p) { munmap(map, map_len); return 0; @@ -402,12 +483,16 @@ static struct dso *load_library(const char *name) p->ino = st.st_ino; p->refcnt = 1; p->name = p->buf; - strcpy(p->name, name); + strcpy(p->name, pathname); + /* Add a shortname only if name arg was not an explicit pathname. */ + if (pathname != name) p->shortname = strrchr(p->name, '/')+1; tail->next = p; p->prev = tail; tail = p; + if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, base); + return p; } @@ -429,7 +514,8 @@ static void load_deps(struct dso *p) p->strings + p->dynv[i+1], p->name); if (runtime) longjmp(rtld_fail, 1); dprintf(2, "%s\n", errbuf); - _exit(127); + ldso_fail = 1; + continue; } if (runtime) { tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2)); @@ -468,12 +554,13 @@ static void reloc_all(struct dso *p) for (; p; p=p->next) { if (p->relocated) continue; decode_vec(p->dynv, dyn, DYN_CNT); - do_relocs(p->base, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ], - 2+(dyn[DT_PLTREL]==DT_RELA), p->syms, p->strings, head); - do_relocs(p->base, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], - 2, p->syms, p->strings, head); - do_relocs(p->base, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], - 3, p->syms, p->strings, head); +#ifdef NEED_ARCH_RELOCS + do_arch_relocs(p, head); +#endif + do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ], + 2+(dyn[DT_PLTREL]==DT_RELA)); + do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2); + do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3); p->relocated = 1; } } @@ -543,10 +630,19 @@ void *__dynlink(int argc, char **argv) env_preload = 0; } + /* 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 = "libc.so"; + lib->name = lib->shortname = "libc.so"; lib->global = 1; ehdr = (void *)lib->base; lib->dynv = (void *)(lib->base + find_dyn( @@ -554,18 +650,53 @@ void *__dynlink(int argc, char **argv) ehdr->e_phnum, ehdr->e_phentsize)); decode_dyn(lib); - /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */ - app->base = 0; - phdr = (void *)aux[AT_PHDR]; - 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); + if (aux[AT_PHDR]) { + size_t interp_off = 0; + /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */ + phdr = (void *)aux[AT_PHDR]; + 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); + else if (phdr->p_type == PT_INTERP) + interp_off = (size_t)phdr->p_vaddr; + } + if (interp_off) lib->name = (char *)app->base + interp_off; + app->name = argv[0]; + app->dynv = (void *)(app->base + find_dyn( + (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT])); + } else { + int fd; + char *ldname = argv[0]; + size_t dyno, l = strlen(ldname); + if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1; + *argv++ = (void *)-1; + if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1; + if (!argv[0]) { + dprintf(2, "musl libc/dynamic program loader\n"); + dprintf(2, "usage: %s pathname%s\n", ldname, + ldd_mode ? "" : " [args]"); + _exit(1); + } + fd = open(argv[0], O_RDONLY); + if (fd < 0) { + dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno)); + _exit(1); + } + runtime = 1; + ehdr = (void *)map_library(fd, &app->map_len, &app->base, &dyno); + 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]; + app->dynv = (void *)(app->base + dyno); + aux[AT_ENTRY] = ehdr->e_entry; } - app->name = argv[0]; app->global = 1; app->constructed = 1; - app->dynv = (void *)(app->base + find_dyn( - (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT])); decode_dyn(app); /* Attach to vdso, if provided by the kernel */ @@ -580,7 +711,7 @@ void *__dynlink(int argc, char **argv) if (phdr->p_type == PT_LOAD) vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset); } - vdso->name = "linux-gate.so.1"; + vdso->name = vdso->shortname = "linux-gate.so.1"; vdso->global = 1; decode_dyn(vdso); vdso->prev = lib; @@ -616,15 +747,20 @@ void *__dynlink(int argc, char **argv) reloc_all(app->next); reloc_all(app); + if (ldso_fail) _exit(127); + if (ldd_mode) _exit(0); + /* 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. */ runtime = 1; +#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; +#endif debug.ver = 1; debug.bp = _dl_debug_state; debug.head = head; @@ -714,25 +850,37 @@ end: static void *do_dlsym(struct dso *p, const char *s, void *ra) { size_t i; - uint32_t h; + 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; - p=p->next; + 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; } - h = hash(s); - sym = lookup(s, h, p->syms, p->hashtab, p->strings); + if (p->ghashtab) { + gh = gnu_hash(s); + sym = gnu_lookup(s, gh, p); + } else { + h = sysv_hash(s); + sym = sysv_lookup(s, h, p); + } if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) return p->base + sym->st_value; if (p->deps) for (i=0; p->deps[i]; i++) { - sym = lookup(s, h, p->deps[i]->syms, - p->deps[i]->hashtab, p->deps[i]->strings); + if (p->deps[i]->ghashtab) { + if (!gh) gh = gnu_hash(s); + sym = gnu_lookup(s, h, p->deps[i]); + } else { + if (!h) h = sysv_hash(s); + sym = sysv_lookup(s, h, p->deps[i]); + } if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) return p->deps[i]->base + sym->st_value; }