track all live threads in an AS-safe, fully-consistent linked list
[musl] / src / env / __init_tls.c
index 89d081e..f1874f2 100644 (file)
@@ -2,75 +2,82 @@
 #include <limits.h>
 #include <sys/mman.h>
 #include <string.h>
+#include <stddef.h>
 #include "pthread_impl.h"
 #include "libc.h"
 #include "atomic.h"
 #include "syscall.h"
 
+volatile int __thread_list_lock;
+
 int __init_tp(void *p)
 {
        pthread_t td = p;
        td->self = td;
-       if (__set_thread_area(TP_ADJ(p)) < 0)
-               return -1;
-       td->tid = td->pid = __syscall(SYS_set_tid_address, &td->tid);
-       td->errno_ptr = &td->errno_val;
-       /* Currently, both of these predicates depend in the same thing:
-        * successful initialization of the thread pointer. However, in
-        * the future, we may support setups where setting the thread
-        * pointer is possible but threads other than the main thread
-        * cannot work, so it's best to keep the predicates separate. */
-       libc.has_thread_pointer = 1;
-       libc.can_do_threads = 1;
+       int r = __set_thread_area(TP_ADJ(p));
+       if (r < 0) return -1;
+       if (!r) libc.can_do_threads = 1;
+       td->detach_state = DT_JOINABLE;
+       td->tid = __syscall(SYS_set_tid_address, &__thread_list_lock);
+       td->locale = &libc.global_locale;
+       td->robust_list.head = &td->robust_list.head;
+       td->next = td->prev = td;
        return 0;
 }
 
-#ifndef SHARED
-
-static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
+static struct builtin_tls {
+       char c;
+       struct pthread pt;
+       void *space[16];
+} builtin_tls[1];
+#define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 
-struct tls_image {
-       void *image;
-       size_t len, size, align;
-} __static_tls ATTR_LIBC_VISIBILITY;
-
-#define T __static_tls
+static struct tls_module main_tls;
 
 void *__copy_tls(unsigned char *mem)
 {
        pthread_t td;
-       if (!T.image) return mem;
-       void **dtv = (void *)mem;
-       dtv[0] = (void *)1;
+       struct tls_module *p;
+       size_t i;
+       uintptr_t *dtv;
+
 #ifdef TLS_ABOVE_TP
-       mem += sizeof(void *) * 2;
-       mem += -((uintptr_t)mem + sizeof(struct pthread)) & (T.align-1);
+       dtv = (uintptr_t*)(mem + libc.tls_size) - (libc.tls_cnt + 1);
+
+       mem += -((uintptr_t)mem + sizeof(struct pthread)) & (libc.tls_align-1);
        td = (pthread_t)mem;
        mem += sizeof(struct pthread);
+
+       for (i=1, p=libc.tls_head; p; i++, p=p->next) {
+               dtv[i] = (uintptr_t)(mem + p->offset) + DTP_OFFSET;
+               memcpy(mem + p->offset, p->image, p->len);
+       }
 #else
+       dtv = (uintptr_t *)mem;
+
        mem += libc.tls_size - sizeof(struct pthread);
-       mem -= (uintptr_t)mem & (T.align-1);
+       mem -= (uintptr_t)mem & (libc.tls_align-1);
        td = (pthread_t)mem;
-       mem -= T.size;
+
+       for (i=1, p=libc.tls_head; p; i++, p=p->next) {
+               dtv[i] = (uintptr_t)(mem - p->offset) + DTP_OFFSET;
+               memcpy(mem - p->offset, p->image, p->len);
+       }
 #endif
-       td->dtv = dtv;
-       dtv[1] = mem;
-       memcpy(mem, T.image, T.len);
+       dtv[0] = libc.tls_cnt;
+       td->dtv = td->dtv_copy = dtv;
        return td;
 }
 
-void *__tls_get_addr(size_t *v)
-{
-       return (char *)__pthread_self()->dtv[1]+v[1];
-}
-
 #if ULONG_MAX == 0xffffffff
 typedef Elf32_Phdr Phdr;
 #else
 typedef Elf64_Phdr Phdr;
 #endif
 
-void __init_tls(size_t *aux)
+extern weak hidden const size_t _DYNAMIC[];
+
+static void static_init_tls(size_t *aux)
 {
        unsigned char *p;
        size_t n;
@@ -78,35 +85,54 @@ void __init_tls(size_t *aux)
        size_t base = 0;
        void *mem;
 
-       libc.tls_size = sizeof(struct pthread);
-
        for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
                phdr = (void *)p;
                if (phdr->p_type == PT_PHDR)
                        base = aux[AT_PHDR] - phdr->p_vaddr;
+               if (phdr->p_type == PT_DYNAMIC && _DYNAMIC)
+                       base = (size_t)_DYNAMIC - phdr->p_vaddr;
                if (phdr->p_type == PT_TLS)
                        tls_phdr = phdr;
+               if (phdr->p_type == PT_GNU_STACK &&
+                   phdr->p_memsz > __default_stacksize)
+                       __default_stacksize =
+                               phdr->p_memsz < DEFAULT_STACK_MAX ?
+                               phdr->p_memsz : DEFAULT_STACK_MAX;
        }
 
        if (tls_phdr) {
-               T.image = (void *)(base + tls_phdr->p_vaddr);
-               T.len = tls_phdr->p_filesz;
-               T.size = tls_phdr->p_memsz;
-               T.align = tls_phdr->p_align;
+               main_tls.image = (void *)(base + tls_phdr->p_vaddr);
+               main_tls.len = tls_phdr->p_filesz;
+               main_tls.size = tls_phdr->p_memsz;
+               main_tls.align = tls_phdr->p_align;
+               libc.tls_cnt = 1;
+               libc.tls_head = &main_tls;
        }
 
-       T.size += (-T.size - (uintptr_t)T.image) & (T.align-1);
-       if (T.align < 4*sizeof(size_t)) T.align = 4*sizeof(size_t);
+       main_tls.size += (-main_tls.size - (uintptr_t)main_tls.image)
+               & (main_tls.align-1);
+#ifdef TLS_ABOVE_TP
+       main_tls.offset = GAP_ABOVE_TP;
+       main_tls.offset += -GAP_ABOVE_TP & (main_tls.align-1);
+#else
+       main_tls.offset = main_tls.size;
+#endif
+       if (main_tls.align < MIN_TLS_ALIGN) main_tls.align = MIN_TLS_ALIGN;
 
-       libc.tls_size = 2*sizeof(void *)+T.size+T.align+sizeof(struct pthread);
+       libc.tls_align = main_tls.align;
+       libc.tls_size = 2*sizeof(void *) + sizeof(struct pthread)
+#ifdef TLS_ABOVE_TP
+               + main_tls.offset
+#endif
+               + main_tls.size + main_tls.align
+               + MIN_TLS_ALIGN-1 & -MIN_TLS_ALIGN;
 
        if (libc.tls_size > sizeof builtin_tls) {
+#ifndef SYS_mmap2
+#define SYS_mmap2 SYS_mmap
+#endif
                mem = (void *)__syscall(
-#ifdef SYS_mmap2
                        SYS_mmap2,
-#else
-                       SYS_mmap,
-#endif
                        0, libc.tls_size, PROT_READ|PROT_WRITE,
                        MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
                /* -4095...-1 cast to void * will crash on dereference anyway,
@@ -116,10 +142,9 @@ void __init_tls(size_t *aux)
                mem = builtin_tls;
        }
 
-       /* Failure to initialize thread pointer is fatal if TLS is used. */
-       if (__init_tp(__copy_tls(mem)) < 0 && tls_phdr)
+       /* Failure to initialize thread pointer is always fatal. */
+       if (__init_tp(__copy_tls(mem)) < 0)
                a_crash();
 }
-#else
-void __init_tls(size_t *auxv) { }
-#endif
+
+weak_alias(static_init_tls, __init_tls);