don't crash if TLS library is loaded into process with no thread pointer

[musl] / src / env / __init_tls.c

diff --git a/src/env/__init_tls.c b/src/env/__init_tls.c
index 4a840cf..6b3cd28 100644 (file)
--- a/src/env/__init_tls.c
+++ b/src/env/__init_tls.c
@@ -7,13 +7,27 @@
 #ifndef SHARED
 
 static void *image;
-static size_t len, bss, align;
+static size_t len, size, align;
 
-void *__copy_tls(unsigned char *mem, size_t cnt)
+void *__copy_tls(unsigned char *mem)
 {
-       mem += ((uintptr_t)image - (uintptr_t)mem) & (align-1);
+       pthread_t td;
+       if (!image) return mem;
+       void **dtv = (void *)mem;
+       dtv[0] = (void *)1;
+       mem += __libc.tls_size - sizeof(struct pthread);
+       mem -= (uintptr_t)mem & (align-1);
+       td = (pthread_t)mem;
+       td->dtv = dtv;
+       mem -= size;
+       dtv[1] = mem;
        memcpy(mem, image, len);
-       return mem + len + bss;
+       return td;
+}
+
+void *__tls_get_addr(size_t *v)
+{
+       return (char *)__pthread_self()->dtv[1]+v[1];
 }
 
 static void *simple(void *p)
@@ -53,18 +67,21 @@ void __init_tls(size_t *auxv)
        }
        if (!tls_phdr) return;
 
-       libc.tls_size = len+bss+align+4*sizeof(size_t)+sizeof(struct pthread);
-
        image = (void *)(base + tls_phdr->p_vaddr);
        len = tls_phdr->p_filesz;
-       bss = tls_phdr->p_memsz - len;
+       size = tls_phdr->p_memsz;
        align = tls_phdr->p_align;
+
+       size += (-size - (uintptr_t)image) & (align-1);
        if (align < 4*sizeof(size_t)) align = 4*sizeof(size_t);
+
+       libc.tls_size = 2*sizeof(void *)+size+align+sizeof(struct pthread);
+
        mem = __mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
                MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
        if (mem == MAP_FAILED) a_crash();
 
-       if (!__install_initial_tls(__copy_tls(mem, 0))) a_crash();
+       if (!__install_initial_tls(__copy_tls(mem))) a_crash();
 }
 #else
 void __init_tls(size_t *auxv) { }