Merge remote-tracking branch 'origin/master' into prelink

* origin/master: (32 commits)
  libubacktrace: fix backtrace support on arm-eabi, which needs libgcc_eh linked too
  getaddrinfo.c: fix incorrect check for ERANGE from gethostbyaddr_r
  getaddrinfo.c: improve code readability. No functional changes
  string: remove unused variable
  x86_64: silence warning if !TLS
  buildsys: prettify ssp.c handling
  madvise is LINUX_SPECIFIC
  test_nptl: fix expected result for tst-cputimer[123]
  test_nptl: fix expected result for tst-clock2 test
  buildsys: make $(LOCAL_INSTALL_PATH) phony
  ether_aton: reject invalid input
  tests: disable ether tests if !HAS_SOCKET
  inet: add ether_aton testcase
  sysconf: clock_getres depends on HAS_REALTIME
  __rt_sigwaitinfo: depends on HAS_REALTIME
  buildsys: minor fixes in Makefile.arch for C6X
  buildsys: minor fixes in Makefile.arch for microblaze
  libubacktrace: enabled for all archs indeed.
  sparc: don't access fp registers when configured for no fpu
  libubacktrace: generic implementation based dwarf
  ...

Conflicts:
	ldso/ldso/dl-elf.c
	ldso/ldso/mips/elfinterp.c
	ldso/ldso/x86_64/elfinterp.c

Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>

1 files changed, 70 insertions, 5 deletions

diff --git a/libubacktrace/backtrace.c b/libubacktrace/backtrace.c
index 872180028..18b91b1bb 100644
--- a/libubacktrace/backtrace.c
+++ b/libubacktrace/backtrace.c
@@ -4,16 +4,81 @@
  * User application that wants to use backtrace needs to be
  * compiled with -fexceptions option and -rdynamic to get full
  * symbols printed.
-
- * Copyright (C) 2010 STMicroelectronics Ltd
+ *
+ * Copyright (C) 2009, 2010 STMicroelectronics Ltd.
+ *
+ * Author(s): Giuseppe Cavallaro <peppe.cavallaro@st.com>
+ * - Initial implementation for glibc
+ *
  * Author(s): Carmelo Amoroso <carmelo.amoroso@st.com>
+ * - Reworked for uClibc
+ *   - use dlsym/dlopen from libdl
+ *   - rewrite initialisation to not use libc_once
+ *   - make it available in static link too
  *
  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
  *
  */
-#error "Arch specific implementation must be provided to properly work"
-int backtrace (void **array, int size)
+
+#include <execinfo.h>
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <unwind.h>
+#include <assert.h>
+#include <stdio.h>
+
+struct trace_arg
 {
-	return -1;
+  void **array;
+  int cnt, size;
+};
+
+static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
+static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
+
+static void backtrace_init (void)
+{
+	void *handle = dlopen ("libgcc_s.so.1", RTLD_LAZY);
+
+	if (handle == NULL
+		|| ((unwind_backtrace = dlsym (handle, "_Unwind_Backtrace")) == NULL)
+		|| ((unwind_getip = dlsym (handle, "_Unwind_GetIP")) == NULL)) {
+		printf("libgcc_s.so.1 must be installed for backtrace to work\n");
+		abort();
+	}
 }
 
+static _Unwind_Reason_Code
+backtrace_helper (struct _Unwind_Context *ctx, void *a)
+{
+	struct trace_arg *arg = a;
+
+	assert (unwind_getip != NULL);
+
+	/* We are first called with address in the __backtrace function. Skip it. */
+	if (arg->cnt != -1)
+		arg->array[arg->cnt] = (void *) unwind_getip (ctx);
+	if (++arg->cnt == arg->size)
+		return _URC_END_OF_STACK;
+	return _URC_NO_REASON;
+}
+
+/*
+ * Perform stack unwinding by using the _Unwind_Backtrace.
+ *
+ * User application that wants to use backtrace needs to be
+ * compiled with -fexceptions option and -rdynamic to get full
+ * symbols printed.
+ */
+int backtrace (void **array, int size)
+{
+	struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
+
+	if (unwind_backtrace == NULL)
+		backtrace_init();
+
+	if (size >= 1)
+		unwind_backtrace (backtrace_helper, &arg);
+
+	return arg.cnt != -1 ? arg.cnt : 0;
+}