implement PT_GNU_RELRO support
[musl] / src / ldso / dynlink.c
index 625f80c..de0f2ac 100644 (file)
@@ -7,12 +7,9 @@
 #include <elf.h>
 #include <sys/mman.h>
 #include <limits.h>
-#include <stdint.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <errno.h>
-#include <limits.h>
-#include <elf.h>
 #include <link.h>
 #include <setjmp.h>
 #include <pthread.h>
@@ -63,6 +60,7 @@ struct dso {
        Sym *syms;
        uint32_t *hashtab;
        uint32_t *ghashtab;
+       int16_t *versym;
        char *strings;
        unsigned char *map;
        size_t map_len;
@@ -71,9 +69,12 @@ struct dso {
        signed char global;
        char relocated;
        char constructed;
-       struct dso **deps;
+       char kernel_mapped;
+       struct dso **deps, *needed_by;
+       char *rpath_orig, *rpath;
        void *tls_image;
        size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
+       size_t relro_start, relro_end;
        void **new_dtv;
        unsigned char *new_tls;
        int new_dtv_idx, new_tls_idx;
@@ -90,20 +91,25 @@ struct symdef {
 #include "reloc.h"
 
 void __init_ssp(size_t *);
-void *__install_initial_tls(void *);
+int __init_tp(void *);
+void __init_libc(char **, char *);
+
+const char *__libc_get_version(void);
 
 static struct dso *head, *tail, *ldso, *fini_head;
-static char *env_path, *sys_path, *r_path;
+static char *env_path, *sys_path;
 static unsigned long long gencnt;
 static int ssp_used;
 static int runtime;
 static int ldd_mode;
 static int ldso_fail;
-static jmp_buf rtld_fail;
+static int noload;
+static jmp_buf *rtld_fail;
 static pthread_rwlock_t lock;
 static struct debug debug;
 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
+static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
 
 struct debug *_dl_debug_addr = &debug;
 
@@ -154,7 +160,8 @@ static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
        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))
+               if ((!dso->versym || dso->versym[i] >= 0)
+                   && (!strcmp(s, strings+syms[i].st_name)))
                        return syms+i;
        }
        return 0;
@@ -162,25 +169,24 @@ static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 
 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 {
-       Sym *sym;
-       char *strings;
+       Sym *syms = dso->syms;
+       char *strings = dso->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];
+       uint32_t i = buckets[h1 % nbuckets];
 
-       if (!n) return 0;
+       if (!i) return 0;
 
-       strings = dso->strings;
-       sym = dso->syms + n;
-       hashval = buckets + nbuckets + (n - hashtab[1]);
+       hashval = buckets + nbuckets + (i - hashtab[1]);
 
-       for (h1 |= 1; ; sym++) {
+       for (h1 |= 1; ; i++) {
                h2 = *hashval++;
-               if ((h1 == (h2|1)) && !strcmp(s, strings + sym->st_name))
-                       return sym;
+               if ((!dso->versym || dso->versym[i] >= 0)
+                   && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
+                       return syms+i;
                if (h2 & 1) break;
        }
 
@@ -188,7 +194,7 @@ static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 }
 
 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
-#define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK)
+#define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 
 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 {
@@ -249,11 +255,12 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
                        name = strings + sym->st_name;
                        ctx = IS_COPY(type) ? head->next : head;
                        def = find_sym(ctx, name, IS_PLT(type));
-                       if (!def.sym && sym->st_info>>4 != STB_WEAK) {
+                       if (!def.sym && (sym->st_shndx != SHN_UNDEF
+                           || sym->st_info>>4 != STB_WEAK)) {
                                snprintf(errbuf, sizeof errbuf,
                                        "Error relocating %s: %s: symbol not found",
                                        dso->name, name);
-                               if (runtime) longjmp(rtld_fail, 1);
+                               if (runtime) longjmp(*rtld_fail, 1);
                                dprintf(2, "%s\n", errbuf);
                                ldso_fail = 1;
                                continue;
@@ -275,27 +282,29 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
  * and "donate" them to the heap by setting up minimal malloc
  * structures and then freeing them. */
 
-static void reclaim(unsigned char *base, size_t start, size_t end)
+static void reclaim(struct dso *dso, size_t start, size_t end)
 {
        size_t *a, *z;
+       if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
+       if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
        start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
        end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
        if (start>end || end-start < 4*sizeof(size_t)) return;
-       a = (size_t *)(base + start);
-       z = (size_t *)(base + end);
+       a = (size_t *)(dso->base + start);
+       z = (size_t *)(dso->base + end);
        a[-2] = 1;
        a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
        z[1] = 1;
        free(a);
 }
 
-static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
+static void reclaim_gaps(struct dso *dso, Phdr *ph, size_t phent, size_t phcnt)
 {
        for (; phcnt--; ph=(void *)((char *)ph+phent)) {
                if (ph->p_type!=PT_LOAD) continue;
                if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
-               reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
-               reclaim(base, ph->p_vaddr+ph->p_memsz,
+               reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
+               reclaim(dso, ph->p_vaddr+ph->p_memsz,
                        ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
        }
 }
@@ -303,39 +312,51 @@ static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phc
 static void *map_library(int fd, struct dso *dso)
 {
        Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
+       void *allocated_buf=0;
        size_t phsize;
        size_t addr_min=SIZE_MAX, addr_max=0, map_len;
        size_t this_min, this_max;
        off_t off_start;
        Ehdr *eh;
-       Phdr *ph;
+       Phdr *ph, *ph0;
        unsigned prot;
-       unsigned char *map, *base;
-       size_t dyn;
+       unsigned char *map=MAP_FAILED, *base;
+       size_t dyn=0;
        size_t tls_image=0;
        size_t i;
 
        ssize_t l = read(fd, buf, sizeof buf);
-       if (l<sizeof *eh) return 0;
        eh = buf;
+       if (l<0) return 0;
+       if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
+               goto noexec;
        phsize = eh->e_phentsize * eh->e_phnum;
-       if (phsize + sizeof *eh > l) return 0;
-       if (eh->e_phoff + phsize > l) {
+       if (phsize > sizeof buf - sizeof *eh) {
+               allocated_buf = malloc(phsize);
+               if (!allocated_buf) return 0;
+               l = pread(fd, allocated_buf, phsize, eh->e_phoff);
+               if (l < 0) goto error;
+               if (l != phsize) goto noexec;
+               ph = ph0 = allocated_buf;
+       } else if (eh->e_phoff + phsize > l) {
                l = pread(fd, buf+1, phsize, eh->e_phoff);
-               if (l != phsize) return 0;
-               eh->e_phoff = sizeof *eh;
+               if (l < 0) goto error;
+               if (l != phsize) goto noexec;
+               ph = ph0 = (void *)(buf + 1);
+       } else {
+               ph = ph0 = (void *)((char *)buf + eh->e_phoff);
        }
-       ph = (void *)((char *)buf + eh->e_phoff);
-       dso->phdr = ph;
-       dso->phnum = eh->e_phnum;
        for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
                if (ph->p_type == PT_DYNAMIC)
                        dyn = ph->p_vaddr;
-               if (ph->p_type == PT_TLS) {
+               else if (ph->p_type == PT_TLS) {
                        tls_image = ph->p_vaddr;
                        dso->tls_align = ph->p_align;
                        dso->tls_len = ph->p_filesz;
                        dso->tls_size = ph->p_memsz;
+               } else if (ph->p_type == PT_GNU_RELRO) {
+                       dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
+                       dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
                }
                if (ph->p_type != PT_LOAD) continue;
                if (ph->p_vaddr < addr_min) {
@@ -349,7 +370,7 @@ static void *map_library(int fd, struct dso *dso)
                        addr_max = ph->p_vaddr+ph->p_memsz;
                }
        }
-       if (!dyn) return 0;
+       if (!dyn) goto noexec;
        addr_max += PAGE_SIZE-1;
        addr_max &= -PAGE_SIZE;
        addr_min &= -PAGE_SIZE;
@@ -360,11 +381,26 @@ static void *map_library(int fd, struct dso *dso)
         * use the invalid part; we just need to reserve the right
         * amount of virtual address space to map over later. */
        map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
-       if (map==MAP_FAILED) return 0;
+       if (map==MAP_FAILED) goto error;
+       /* If the loaded file is not relocatable and the requested address is
+        * not available, then the load operation must fail. */
+       if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
+               errno = EBUSY;
+               goto error;
+       }
        base = map - addr_min;
-       ph = (void *)((char *)buf + eh->e_phoff);
-       for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
+       dso->phdr = 0;
+       dso->phnum = 0;
+       for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
                if (ph->p_type != PT_LOAD) continue;
+               /* Check if the programs headers are in this load segment, and
+                * if so, record the address for use by dl_iterate_phdr. */
+               if (!dso->phdr && eh->e_phoff >= ph->p_offset
+                   && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
+                       dso->phdr = (void *)(base + ph->p_vaddr
+                               + (eh->e_phoff-ph->p_offset));
+                       dso->phnum = eh->e_phnum;
+               }
                /* Reuse the existing mapping for the lowest-address LOAD */
                if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
                this_min = ph->p_vaddr & -PAGE_SIZE;
@@ -389,34 +425,95 @@ static void *map_library(int fd, struct dso *dso)
                                goto error;
                        break;
                }
-       if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff),
-               eh->e_phentsize, eh->e_phnum);
        dso->map = map;
        dso->map_len = map_len;
        dso->base = base;
        dso->dynv = (void *)(base+dyn);
        if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
+       if (!runtime) reclaim_gaps(dso, ph0, eh->e_phentsize, eh->e_phnum);
+       free(allocated_buf);
        return map;
+noexec:
+       errno = ENOEXEC;
 error:
-       munmap(map, map_len);
+       if (map!=MAP_FAILED) munmap(map, map_len);
+       free(allocated_buf);
        return 0;
 }
 
-static int path_open(const char *name, const char *search, char *buf, size_t buf_size)
+static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 {
-       const char *s=search, *z;
-       int l, fd;
+       size_t l;
+       int fd;
        for (;;) {
-               while (*s==':') s++;
-               if (!*s) return -1;
-               z = strchr(s, ':');
-               l = z ? z-s : strlen(s);
-               snprintf(buf, buf_size, "%.*s/%s", l, s, name);
+               s += strspn(s, ":\n");
+               l = strcspn(s, ":\n");
+               if (l-1 >= INT_MAX) return -1;
+               if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
+                       continue;
                if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
                s += l;
        }
 }
 
+static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
+{
+       size_t n, l;
+       const char *s, *t, *origin;
+       char *d;
+       if (p->rpath) return 0;
+       if (!p->rpath_orig) return -1;
+       if (!strchr(p->rpath_orig, '$')) {
+               p->rpath = p->rpath_orig;
+               return 0;
+       }
+       n = 0;
+       s = p->rpath_orig;
+       while ((t=strchr(s, '$'))) {
+               if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
+                       return -1;
+               s = t+1;
+               n++;
+       }
+       if (n > SSIZE_MAX/PATH_MAX) return -1;
+
+       if (p->kernel_mapped) {
+               /* $ORIGIN searches cannot be performed for the main program
+                * when it is suid/sgid/AT_SECURE. This is because the
+                * pathname is under the control of the caller of execve.
+                * For libraries, however, $ORIGIN can be processed safely
+                * since the library's pathname came from a trusted source
+                * (either system paths or a call to dlopen). */
+               if (libc.secure)
+                       return -1;
+               l = readlink("/proc/self/exe", buf, buf_size);
+               if (l >= buf_size)
+                       return -1;
+               buf[l] = 0;
+               origin = buf;
+       } else {
+               origin = p->name;
+       }
+       t = strrchr(origin, '/');
+       l = t ? t-origin : 0;
+       p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
+       if (!p->rpath) return -1;
+
+       d = p->rpath;
+       s = p->rpath_orig;
+       while ((t=strchr(s, '$'))) {
+               memcpy(d, s, t-s);
+               d += t-s;
+               memcpy(d, origin, l);
+               d += l;
+               /* It was determined previously that the '$' is followed
+                * either by "ORIGIN" or "{ORIGIN}". */
+               s = t + 7 + 2*(t[1]=='{');
+       }
+       strcpy(d, s);
+       return 0;
+}
+
 static void decode_dyn(struct dso *p)
 {
        size_t dyn[DYN_CNT] = {0};
@@ -425,21 +522,25 @@ static void decode_dyn(struct dso *p)
        p->strings = (void *)(p->base + dyn[DT_STRTAB]);
        if (dyn[0]&(1<<DT_HASH))
                p->hashtab = (void *)(p->base + dyn[DT_HASH]);
+       if (dyn[0]&(1<<DT_RPATH))
+               p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
        if (search_vec(p->dynv, dyn, DT_GNU_HASH))
                p->ghashtab = (void *)(p->base + *dyn);
+       if (search_vec(p->dynv, dyn, DT_VERSYM))
+               p->versym = (void *)(p->base + *dyn);
 }
 
-static struct dso *load_library(const char *name)
+static struct dso *load_library(const char *name, struct dso *needed_by)
 {
        char buf[2*NAME_MAX+2];
        const char *pathname;
-       unsigned char *base, *map;
-       size_t map_len;
+       unsigned char *map;
        struct dso *p, temp_dso = {0};
        int fd;
        struct stat st;
        size_t alloc_size;
        int n_th = 0;
+       int is_self = 0;
 
        /* Catch and block attempts to reload the implementation itself */
        if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
@@ -448,17 +549,33 @@ static struct dso *load_library(const char *name)
                char *z = strchr(name, '.');
                if (z) {
                        size_t l = z-name;
-                       for (rp=reserved; *rp && memcmp(name+3, rp, l-3); rp+=strlen(rp)+1);
+                       for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
                        if (*rp) {
-                               if (!ldso->prev) {
-                                       tail->next = ldso;
-                                       ldso->prev = tail;
-                                       tail = ldso->next ? ldso->next : ldso;
+                               if (ldd_mode) {
+                                       /* Track which names have been resolved
+                                        * and only report each one once. */
+                                       static unsigned reported;
+                                       unsigned mask = 1U<<(rp-reserved);
+                                       if (!(reported & mask)) {
+                                               reported |= mask;
+                                               dprintf(1, "\t%s => %s (%p)\n",
+                                                       name, ldso->name,
+                                                       ldso->base);
+                                       }
                                }
-                               return ldso;
+                               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;
+               }
+               return ldso;
+       }
        if (strchr(name, '/')) {
                pathname = name;
                fd = open(name, O_RDONLY|O_CLOEXEC);
@@ -472,19 +589,44 @@ static struct dso *load_library(const char *name)
                }
                if (strlen(name) > NAME_MAX) return 0;
                fd = -1;
-               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 (env_path) fd = path_open(name, env_path, buf, sizeof buf);
+               for (p=needed_by; fd < 0 && p; p=p->needed_by)
+                       if (!fixup_rpath(p, buf, sizeof buf))
+                               fd = path_open(name, p->rpath, buf, sizeof buf);
                if (fd < 0) {
                        if (!sys_path) {
-                               FILE *f = fopen(ETC_LDSO_PATH, "rbe");
+                               char *prefix = 0;
+                               size_t prefix_len;
+                               if (ldso->name[0]=='/') {
+                                       char *s, *t, *z;
+                                       for (s=t=z=ldso->name; *s; s++)
+                                               if (*s=='/') z=t, t=s;
+                                       prefix_len = z-ldso->name;
+                                       if (prefix_len < PATH_MAX)
+                                               prefix = ldso->name;
+                               }
+                               if (!prefix) {
+                                       prefix = "";
+                                       prefix_len = 0;
+                               }
+                               char etc_ldso_path[prefix_len + 1
+                                       + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
+                               snprintf(etc_ldso_path, sizeof etc_ldso_path,
+                                       "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
+                                       (int)prefix_len, prefix);
+                               FILE *f = fopen(etc_ldso_path, "rbe");
                                if (f) {
-                                       if (getline(&sys_path, (size_t[1]){0}, f) > 0)
-                                               sys_path[strlen(sys_path)-1]=0;
+                                       if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
+                                               free(sys_path);
+                                               sys_path = "";
+                                       }
                                        fclose(f);
+                               } else if (errno != ENOENT) {
+                                       sys_path = "";
                                }
                        }
-                       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);
+                       if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
+                       fd = path_open(name, sys_path, buf, sizeof buf);
                }
                pathname = buf;
        }
@@ -505,7 +647,7 @@ static struct dso *load_library(const char *name)
                        return p;
                }
        }
-       map = map_library(fd, &temp_dso);
+       map = noload ? 0 : map_library(fd, &temp_dso);
        close(fd);
        if (!map) return 0;
 
@@ -524,7 +666,7 @@ static struct dso *load_library(const char *name)
        }
        p = calloc(1, alloc_size);
        if (!p) {
-               munmap(map, map_len);
+               munmap(map, temp_dso.map_len);
                return 0;
        }
        memcpy(p, &temp_dso, sizeof temp_dso);
@@ -532,14 +674,16 @@ static struct dso *load_library(const char *name)
        p->dev = st.st_dev;
        p->ino = st.st_ino;
        p->refcnt = 1;
+       p->needed_by = needed_by;
        p->name = p->buf;
        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;
        if (p->tls_image) {
-               if (runtime && !__pthread_self_init()) {
+               if (runtime && !libc.has_thread_pointer) {
+                       munmap(map, p->map_len);
                        free(p);
-                       munmap(map, map_len);
+                       errno = ENOSYS;
                        return 0;
                }
                p->tls_id = ++tls_cnt;
@@ -563,7 +707,7 @@ static struct dso *load_library(const char *name)
        p->prev = tail;
        tail = p;
 
-       if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, base);
+       if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 
        return p;
 }
@@ -573,31 +717,26 @@ static void load_deps(struct dso *p)
        size_t i, ndeps=0;
        struct dso ***deps = &p->deps, **tmp, *dep;
        for (; p; p=p->next) {
-               for (i=0; p->dynv[i]; i+=2) {
-                       if (p->dynv[i] != DT_RPATH) continue;
-                       r_path = (void *)(p->strings + p->dynv[i+1]);
-               }
                for (i=0; p->dynv[i]; i+=2) {
                        if (p->dynv[i] != DT_NEEDED) continue;
-                       dep = load_library(p->strings + p->dynv[i+1]);
+                       dep = load_library(p->strings + p->dynv[i+1], p);
                        if (!dep) {
                                snprintf(errbuf, sizeof errbuf,
                                        "Error loading shared library %s: %m (needed by %s)",
                                        p->strings + p->dynv[i+1], p->name);
-                               if (runtime) longjmp(rtld_fail, 1);
+                               if (runtime) longjmp(*rtld_fail, 1);
                                dprintf(2, "%s\n", errbuf);
                                ldso_fail = 1;
                                continue;
                        }
                        if (runtime) {
                                tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
-                               if (!tmp) longjmp(rtld_fail, 1);
+                               if (!tmp) longjmp(*rtld_fail, 1);
                                tmp[ndeps++] = dep;
                                tmp[ndeps] = 0;
                                *deps = tmp;
                        }
                }
-               r_path = 0;
        }
 }
 
@@ -610,7 +749,7 @@ static void load_preload(char *s)
                for (z=s; *z && !isspace(*z); z++);
                tmp = *z;
                *z = 0;
-               load_library(s);
+               load_library(s, 0);
                *z = tmp;
        }
 }
@@ -633,6 +772,17 @@ static void reloc_all(struct dso *p)
                        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);
+
+               if (p->relro_start != p->relro_end &&
+                   mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
+                       snprintf(errbuf, sizeof errbuf,
+                               "Error relocating %s: RELRO protection failed",
+                               p->name);
+                       if (runtime) longjmp(*rtld_fail, 1);
+                       dprintf(2, "%s\n", errbuf);
+                       ldso_fail = 1;
+               }
+
                p->relocated = 1;
        }
 }
@@ -649,6 +799,10 @@ static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 {
        size_t min_addr = -1, max_addr = 0;
        for (; cnt--; ph = (void *)((char *)ph + stride)) {
+               if (ph->p_type == PT_GNU_RELRO) {
+                       p->relro_start = ph->p_vaddr & -PAGE_SIZE;
+                       p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
+               }
                if (ph->p_type != PT_LOAD) continue;
                if (ph->p_vaddr < min_addr)
                        min_addr = ph->p_vaddr;
@@ -668,7 +822,15 @@ static void do_fini()
        for (p=fini_head; p; p=p->fini_next) {
                if (!p->constructed) continue;
                decode_vec(p->dynv, dyn, DYN_CNT);
-               ((void (*)(void))(p->base + dyn[DT_FINI]))();
+               if (dyn[0] & (1<<DT_FINI_ARRAY)) {
+                       size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
+                       size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
+                       while (n--) ((void (*)(void))*--fn)();
+               }
+#ifndef NO_LEGACY_INITFINI
+               if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
+                       ((void (*)(void))(p->base + dyn[DT_FINI]))();
+#endif
        }
 }
 
@@ -684,12 +846,23 @@ static void do_init_fini(struct dso *p)
                if (p->constructed) continue;
                p->constructed = 1;
                decode_vec(p->dynv, dyn, DYN_CNT);
-               if (dyn[0] & (1<<DT_FINI)) {
+               if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
                        p->fini_next = fini_head;
                        fini_head = p;
                }
-               if (dyn[0] & (1<<DT_INIT))
+#ifndef NO_LEGACY_INITFINI
+               if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
                        ((void (*)(void))(p->base + dyn[DT_INIT]))();
+#endif
+               if (dyn[0] & (1<<DT_INIT_ARRAY)) {
+                       size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
+                       size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
+                       while (n--) ((void (*)(void))*fn++)();
+               }
+               if (!need_locking && libc.threads_minus_1) {
+                       need_locking = 1;
+                       pthread_mutex_lock(&init_fini_lock);
+               }
        }
        if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 }
@@ -698,15 +871,31 @@ void _dl_debug_state(void)
 {
 }
 
+void __reset_tls()
+{
+       pthread_t self = __pthread_self();
+       struct dso *p;
+       for (p=head; p; p=p->next) {
+               if (!p->tls_id || !self->dtv[p->tls_id]) continue;
+               memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
+               memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
+                       p->tls_size - p->tls_len);
+               if (p->tls_id == (size_t)self->dtv[0]) break;
+       }
+}
+
 void *__copy_tls(unsigned char *mem)
 {
        pthread_t td;
        struct dso *p;
 
-       if (!tls_cnt) return mem;
-
        void **dtv = (void *)mem;
        dtv[0] = (void *)tls_cnt;
+       if (!tls_cnt) {
+               td = (void *)(dtv+1);
+               td->dtv = dtv;
+               return td;
+       }
 
 #ifdef TLS_ABOVE_TP
        mem += sizeof(void *) * (tls_cnt+1);
@@ -737,13 +926,13 @@ void *__copy_tls(unsigned char *mem)
 void *__tls_get_addr(size_t *v)
 {
        pthread_t self = __pthread_self();
-       if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
+       if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
                return (char *)self->dtv[v[0]]+v[1];
 
        /* Block signals to make accessing new TLS async-signal-safe */
        sigset_t set;
        pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
-       if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
+       if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
                pthread_sigmask(SIG_SETMASK, &set, 0);
                return (char *)self->dtv[v[0]]+v[1];
        }
@@ -756,10 +945,10 @@ void *__tls_get_addr(size_t *v)
        for (p=head; p->tls_id != v[0]; p=p->next);
 
        /* Get new DTV space from new DSO if needed */
-       if (!self->dtv || v[0] > (size_t)self->dtv[0]) {
+       if (v[0] > (size_t)self->dtv[0]) {
                void **newdtv = p->new_dtv +
                        (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
-               if (self->dtv) memcpy(newdtv, self->dtv,
+               memcpy(newdtv, self->dtv,
                        ((size_t)self->dtv[0]+1) * sizeof(void *));
                newdtv[0] = (void *)v[0];
                self->dtv = newdtv;
@@ -798,6 +987,8 @@ void *__dynlink(int argc, char **argv)
        char *env_preload=0;
        size_t vdso_base;
        size_t *auxv;
+       char **envp = argv+argc+1;
+       void *initial_tls;
 
        /* Find aux vector just past environ[] */
        for (i=argc+1; argv[i]; i++)
@@ -814,7 +1005,9 @@ void *__dynlink(int argc, char **argv)
          || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
                env_path = 0;
                env_preload = 0;
+               libc.secure = 1;
        }
+       libc.page_size = aux[AT_PAGESZ];
 
        /* 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
@@ -830,12 +1023,13 @@ void *__dynlink(int argc, char **argv)
        lib->base = (void *)aux[AT_BASE];
        lib->name = lib->shortname = "libc.so";
        lib->global = 1;
+       lib->kernel_mapped = 1;
        ehdr = (void *)lib->base;
        lib->phnum = ehdr->e_phnum;
        lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
        find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
        lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
-                    ehdr->e_phnum, ehdr->e_phentsize));
+               ehdr->e_phnum, ehdr->e_phentsize));
        decode_dyn(lib);
 
        if (aux[AT_PHDR]) {
@@ -858,7 +1052,12 @@ void *__dynlink(int argc, char **argv)
                }
                if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
                if (interp_off) lib->name = (char *)app->base + interp_off;
-               app->name = argv[0];
+               if ((aux[0] & (1UL<<AT_EXECFN))
+                   && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
+                       app->name = (char *)aux[AT_EXECFN];
+               else
+                       app->name = argv[0];
+               app->kernel_mapped = 1;
                app->dynv = (void *)(app->base + find_dyn(
                        (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
                find_map_range((void *)aux[AT_PHDR],
@@ -871,8 +1070,11 @@ void *__dynlink(int argc, char **argv)
                *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,
+                       dprintf(2, "musl libc\n"
+                               "Version %s\n"
+                               "Dynamic Program Loader\n"
+                               "Usage: %s [--] pathname%s\n",
+                               __libc_get_version(), ldname,
                                ldd_mode ? "" : " [args]");
                        _exit(1);
                }
@@ -891,9 +1093,17 @@ void *__dynlink(int argc, char **argv)
                close(fd);
                lib->name = ldname;
                app->name = argv[0];
-               app->phnum = ehdr->e_phnum;
-               app->phdr = (void *)(app->base + ehdr->e_phoff);
-               aux[AT_ENTRY] = ehdr->e_entry;
+               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; i<app->phnum; i++) {
+                               if (app->phdr[i].p_type == PT_INTERP)
+                                       lib->name = (void *)(app->base
+                                               + app->phdr[i].p_vaddr);
+                       }
+                       dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
+               }
        }
        if (app->tls_size) {
                app->tls_id = tls_cnt = 1;
@@ -910,7 +1120,6 @@ void *__dynlink(int argc, char **argv)
                tls_align = MAXP2(tls_align, app->tls_align);
        }
        app->global = 1;
-       app->constructed = 1;
        decode_dyn(app);
 
        /* Attach to vdso, if provided by the kernel */
@@ -924,7 +1133,8 @@ 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 = vdso->shortname = "linux-gate.so.1";
+               vdso->name = "";
+               vdso->shortname = "linux-gate.so.1";
                vdso->global = 1;
                decode_dyn(vdso);
                vdso->prev = lib;
@@ -944,9 +1154,9 @@ void *__dynlink(int argc, char **argv)
        /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
 
        /* Donate unused parts of app and library mapping to malloc */
-       reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
+       reclaim_gaps(app, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
        ehdr = (void *)lib->base;
-       reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
+       reclaim_gaps(lib, (void *)(lib->base+ehdr->e_phoff),
                ehdr->e_phentsize, ehdr->e_phnum);
 
        /* Load preload/needed libraries, add their symbols to the global
@@ -957,19 +1167,29 @@ void *__dynlink(int argc, char **argv)
        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;
+#endif
+
        reloc_all(app->next);
        reloc_all(app);
 
        update_tls_size();
-       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))) {
+       if (libc.tls_size > sizeof builtin_tls) {
+               initial_tls = calloc(libc.tls_size, 1);
+               if (!initial_tls) {
                        dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
                                argv[0], libc.tls_size);
                        _exit(127);
                }
+       } else {
+               initial_tls = builtin_tls;
+       }
+       if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
+               dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
+               _exit(127);
        }
 
        if (ldso_fail) _exit(127);
@@ -981,11 +1201,6 @@ void *__dynlink(int argc, char **argv)
         * 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;
@@ -994,11 +1209,11 @@ void *__dynlink(int argc, char **argv)
        _dl_debug_state();
 
        if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
-
+       __init_libc(envp, argv[0]);
        atexit(do_fini);
+       errno = 0;
        do_init_fini(tail);
 
-       errno = 0;
        return (void *)aux[AT_ENTRY];
 }
 
@@ -1008,6 +1223,7 @@ void *dlopen(const char *file, int mode)
        size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
        size_t i;
        int cs;
+       jmp_buf jb;
 
        if (!file) return head;
 
@@ -1020,8 +1236,10 @@ void *dlopen(const char *file, int mode)
        orig_tls_offset = tls_offset;
        orig_tls_align = tls_align;
        orig_tail = tail;
+       noload = mode & RTLD_NOLOAD;
 
-       if (setjmp(rtld_fail)) {
+       rtld_fail = &jb;
+       if (setjmp(*rtld_fail)) {
                /* Clean up anything new that was (partially) loaded */
                if (p && p->deps) for (i=0; p->deps[i]; i++)
                        if (p->deps[i]->global < 0)
@@ -1040,11 +1258,13 @@ void *dlopen(const char *file, int mode)
                p = 0;
                errflag = 1;
                goto end;
-       } else p = load_library(file);
+       } else p = load_library(file, head);
 
        if (!p) {
-               snprintf(errbuf, sizeof errbuf,
-                       "Error loading shared library %s: %m", file);
+               snprintf(errbuf, sizeof errbuf, noload ?
+                       "Library %s is not already loaded" :
+                       "Error loading shared library %s: %m",
+                       file);
                errflag = 1;
                goto end;
        }
@@ -1084,6 +1304,15 @@ end:
        return p;
 }
 
+static int invalid_dso_handle(void *h)
+{
+       struct dso *p;
+       for (p=head; p; p=p->next) if (h==p) return 0;
+       snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
+       errflag = 1;
+       return 1;
+}
+
 static void *do_dlsym(struct dso *p, const char *s, void *ra)
 {
        size_t i;
@@ -1103,6 +1332,8 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra)
                        return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
                return def.dso->base + def.sym->st_value;
        }
+       if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
+               return 0;
        if (p->ghashtab) {
                gh = gnu_hash(s);
                sym = gnu_lookup(s, gh, p);
@@ -1133,7 +1364,7 @@ failed:
        return 0;
 }
 
-int __dladdr(void *addr, Dl_info *info)
+int __dladdr(const void *addr, Dl_info *info)
 {
        struct dso *p;
        Sym *sym;
@@ -1158,7 +1389,7 @@ int __dladdr(void *addr, Dl_info *info)
                uint32_t *hashval;
                buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
                sym += p->ghashtab[1];
-               for (i = 0; i < p->ghashtab[0]; i++) {
+               for (i = nsym = 0; i < p->ghashtab[0]; i++) {
                        if (buckets[i] > nsym)
                                nsym = buckets[i];
                }
@@ -1171,7 +1402,7 @@ int __dladdr(void *addr, Dl_info *info)
        }
 
        for (; nsym; nsym--, sym++) {
-               if (sym->st_shndx && sym->st_value
+               if (sym->st_value
                 && (1<<(sym->st_info&0xf) & OK_TYPES)
                 && (1<<(sym->st_info>>4) & OK_BINDS)) {
                        void *symaddr = p->base + sym->st_value;
@@ -1229,6 +1460,12 @@ int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void
        return ret;
 }
 #else
+static int invalid_dso_handle(void *h)
+{
+       snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
+       errflag = 1;
+       return 1;
+}
 void *dlopen(const char *file, int mode)
 {
        return 0;
@@ -1237,12 +1474,24 @@ void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
 {
        return 0;
 }
-int __dladdr (void *addr, Dl_info *info)
+int __dladdr (const void *addr, Dl_info *info)
 {
        return 0;
 }
 #endif
 
+int __dlinfo(void *dso, int req, void *res)
+{
+       if (invalid_dso_handle(dso)) return -1;
+       if (req != RTLD_DI_LINKMAP) {
+               snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
+               errflag = 1;
+               return -1;
+       }
+       *(struct link_map **)res = dso;
+       return 0;
+}
+
 char *dlerror()
 {
        if (!errflag) return 0;
@@ -1252,5 +1501,5 @@ char *dlerror()
 
 int dlclose(void *p)
 {
-       return 0;
+       return invalid_dso_handle(p);
 }