From 064af42167bf4fc9aaea2702d80ce08074b889c0 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@nicira.com>
Date: Wed, 8 Jul 2009 13:19:16 -0700
Subject: Import from old repository commit
 61ef2b42a9c4ba8e1600f15bb0236765edc2ad45.

---
 lib/backtrace.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 lib/backtrace.c

(limited to 'lib/backtrace.c')

diff --git a/lib/backtrace.c b/lib/backtrace.c
new file mode 100644
index 000000000..070603900
--- /dev/null
+++ b/lib/backtrace.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2008, 2009 Nicira Networks.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <config.h>
+#include "backtrace.h"
+#include <errno.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include "compiler.h"
+
+#define THIS_MODULE VLM_backtrace
+#include "vlog.h"
+
+static uintptr_t UNUSED
+get_max_stack(void)
+{
+    static const char file_name[] = "/proc/self/maps";
+    char line[1024];
+    int line_number;
+    FILE *f;
+
+    f = fopen(file_name, "r");
+    if (f == NULL) {
+        VLOG_WARN("opening %s failed: %s", file_name, strerror(errno));
+        return -1;
+    }
+
+    for (line_number = 1; fgets(line, sizeof line, f); line_number++) {
+        if (strstr(line, "[stack]")) {
+            uintptr_t end;
+            if (sscanf(line, "%*"SCNxPTR"-%"SCNxPTR, &end) != 1) {
+                VLOG_WARN("%s:%d: parse error", file_name, line_number);
+                continue;
+            }
+            fclose(f);
+            return end;
+        }
+    }
+    fclose(f);
+
+    VLOG_WARN("%s: no stack found", file_name);
+    return -1;
+}
+
+static uintptr_t
+stack_high(void)
+{
+    static uintptr_t high;
+    if (!high) {
+        high = get_max_stack();
+    }
+    return high;
+}
+
+static uintptr_t
+stack_low(void)
+{
+#ifdef __i386__
+    uintptr_t low;
+    asm("movl %%esp,%0" : "=g" (low));
+    return low;
+#else
+    /* This causes a warning in GCC that cannot be disabled, so use it only on
+     * non-x86. */
+    int dummy;
+    return (uintptr_t) &dummy;
+#endif
+}
+
+static bool
+in_stack(void *p)
+{
+    uintptr_t address = (uintptr_t) p;
+    return address >= stack_low() && address < stack_high();
+}
+
+void
+backtrace_capture(struct backtrace *backtrace)
+{
+    void **frame;
+    size_t n;
+
+    n = 0;
+    for (frame = __builtin_frame_address(1);
+         frame != NULL && in_stack(frame) && frame[0] != NULL
+             && n < BACKTRACE_MAX_FRAMES;
+         frame = frame[0])
+    {
+        backtrace->frames[n++] = (uintptr_t) frame[1];
+    }
+    backtrace->n_frames = n;
+}
-- 
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