fix regression in pre-v7 arm on kernels with kuser helper removed

the arm atomics/TLS runtime selection code is called from
__set_thread_area and depends on having libc.auxv and __hwcap
available. commit 71f099cb7db821c51d8f39dfac622c61e54d794c moved the
first call to __set_thread_area to the top of dynamic linking stage 3,
before this data is made available, causing the runtime detection code
to always see __hwcap as zero and thereby select the atomics/TLS
implementations based on kuser helper.

upcoming work on superh will use similar runtime detection.

ideally this early-init code should be cleanly refactored and shared
between the dynamic linker and static-linked startup.

diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 42b056d2f264aef11978ebf5ebeb8e48523dde69..71252d0327cbb76c027f1e13feb988fe92773f6e 100644 (file)
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -1192,6 +1192,17 @@ _Noreturn void __dls3(size_t *sp)
        char **argv_orig = argv;
        char **envp = argv+argc+1;
 
+       /* Find aux vector just past environ[] and use it to initialize
+        * global data that may be needed before we can make syscalls. */
+       __environ = envp;
+       for (i=argc+1; argv[i]; i++);
+       libc.auxv = auxv = (void *)(argv+i+1);
+       decode_vec(auxv, aux, AUX_CNT);
+       __hwcap = aux[AT_HWCAP];
+       libc.page_size = aux[AT_PAGESZ];
+       libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
+               || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
+
        /* Setup early thread pointer in builtin_tls for ldso/libc itself to
         * use during dynamic linking. If possible it will also serve as the
         * thread pointer at runtime. */
@@ -1200,25 +1211,11 @@ _Noreturn void __dls3(size_t *sp)
                a_crash();
        }
 
-       /* 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);
-
        /* Only trust user/env if kernel says we're not suid/sgid */
-       if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
-         || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
-               env_path = 0;
-               env_preload = 0;
-               libc.secure = 1;
+       if (!libc.secure) {
+               env_path = getenv("LD_LIBRARY_PATH");
+               env_preload = getenv("LD_PRELOAD");
        }
-       libc.page_size = aux[AT_PAGESZ];
-       libc.auxv = auxv;
 
        /* If the main program was already loaded by the kernel,
         * AT_PHDR will point to some location other than the dynamic