Improve ARM CPU info reporting.

This patch improves several things for Linux/ARM:

- Better detection of the number of CPUs on the target
  device. The content of /proc/cpuinfo only matches the
  number of "online" CPUs, which varies over time with
  recent Android devices.

- Reconstruct the CPUID and ELF hwcaps values from
  /proc/cpuinfo, this is useful to better identify
  target devices in minidumps.

- Make minidump_dump display the new information
  in useful ways.

- Write a small helper class to parse /proc/cpuinfo
  and also use it for x86/64.

- Write a small helper class to parse sysfds cpu lists.

- Add a my_memchr() implementation.

- Add unit tests.

Tested on a Nexus S (1 CPU), Galaxy Nexus (2 CPUs)
and a Nexus 4 (4 CPUs).

Review URL: https://breakpad.appspot.com/540003

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1160 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 130 insertions, 0 deletions

diff --git a/src/client/linux/minidump_writer/proc_cpuinfo_reader.h b/src/client/linux/minidump_writer/proc_cpuinfo_reader.h
new file mode 100644
index 00000000..d9461bf3
--- /dev/null
+++ b/src/client/linux/minidump_writer/proc_cpuinfo_reader.h
@@ -0,0 +1,130 @@
+// Copyright (c) 2013, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_
+
+#include <stdint.h>
+#include <assert.h>
+#include <string.h>
+
+#include "client/linux/minidump_writer/line_reader.h"
+#include "common/linux/linux_libc_support.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+namespace google_breakpad {
+
+// A class for reading /proc/cpuinfo without using fopen/fgets or other
+// functions which may allocate memory.
+class ProcCpuInfoReader {
+public:
+  ProcCpuInfoReader(int fd)
+    : line_reader_(fd), pop_count_(-1) {
+  }
+
+  // Return the next field name, or NULL in case of EOF.
+  // field: (output) Pointer to zero-terminated field name.
+  // Returns true on success, or false on EOF or error (line too long).
+  bool GetNextField(const char** field) {
+    for (;;) {
+      const char* line;
+      unsigned line_len;
+
+      // Try to read next line.
+      if (pop_count_ >= 0) {
+        line_reader_.PopLine(pop_count_);
+        pop_count_ = -1;
+      }
+
+      if (!line_reader_.GetNextLine(&line, &line_len))
+        return false;
+
+      pop_count_ = static_cast<int>(line_len);
+
+      const char* line_end = line + line_len;
+
+      // Expected format: <field-name> <space>+ ':' <space> <value>
+      // Note that:
+      //   - empty lines happen.
+      //   - <field-name> can contain spaces.
+      //   - some fields have an empty <value>
+      char* sep = static_cast<char*>(my_memchr(line, ':', line_len));
+      if (sep == NULL)
+        continue;
+
+      // Record the value. Skip leading space after the column to get
+      // its start.
+      const char* val = sep+1;
+      while (val < line_end && my_isspace(*val))
+        val++;
+
+      value_ = val;
+      value_len_ = static_cast<size_t>(line_end - val);
+
+      // Remove trailing spaces before the column to properly 0-terminate
+      // the field name.
+      while (sep > line && my_isspace(sep[-1]))
+        sep--;
+
+      if (sep == line)
+        continue;
+
+      // zero-terminate field name.
+      *sep = '\0';
+
+      *field = line;
+      return true;
+    }
+  }
+
+  // Return the field value. This must be called after a succesful
+  // call to GetNextField().
+  const char* GetValue() {
+    assert(value_);
+    return value_;
+  }
+
+  // Same as GetValue(), but also returns the length in characters of
+  // the value.
+  const char* GetValueAndLen(size_t* length) {
+    assert(value_);
+    *length = value_len_;
+    return value_;
+  }
+
+private:
+  LineReader line_reader_;
+  int pop_count_;
+  const char* value_;
+  size_t value_len_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_