Revert 57921 - Pull seccomp-sandbox in via DEPS rather than using an in-tree copy

This means changes to the sandbox won't have to be committed twice, to
both trees.

BUG=none
TEST=smoke test of running chromium with --enable-seccomp-sandbox

Review URL: http://codereview.chromium.org/3249003

TBR=mseaborn@chromium.org
Review URL: http://codereview.chromium.org/3245011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@57933 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 363 insertions, 0 deletions

diff --git a/sandbox/linux/seccomp/debug.cc b/sandbox/linux/seccomp/debug.cc
new file mode 100644
index 0000000..5d6de49
--- /dev/null
+++ b/sandbox/linux/seccomp/debug.cc
@@ -0,0 +1,363 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NDEBUG
+
+#include "debug.h"
+
+namespace playground {
+
+bool Debug::enabled_;
+int  Debug::numSyscallNames_;
+const char **Debug::syscallNames_;
+std::map<int, std::string> Debug::syscallNamesMap_;
+
+Debug Debug::debug_;
+
+Debug::Debug() {
+  // Logging is disabled by default, but can be turned on by setting an
+  // appropriate environment variable. Initialize this code from a global
+  // constructor, so that it runs before the sandbox is turned on.
+  enabled_ = !!getenv("SECCOMP_SANDBOX_DEBUGGING");
+
+  // Read names of system calls from header files, if available. Symbolic
+  // names make debugging so much nicer.
+  if (enabled_) {
+    static const char *filenames[] = {
+      #if __WORDSIZE == 64
+      "/usr/include/asm/unistd_64.h",
+      #elif __WORDSIZE == 32
+      "/usr/include/asm/unistd_32.h",
+      #endif
+      "/usr/include/asm/unistd.h",
+      NULL };
+    numSyscallNames_ = 0;
+    for (const char **fn = filenames; *fn; ++fn) {
+      FILE *fp = fopen(*fn, "r");
+      if (fp) {
+        std::string baseName;
+        int         baseNum = -1;
+        char buf[80];
+        while (fgets(buf, sizeof(buf), fp)) {
+          // Check if the line starts with "#define"
+          static const char* whitespace = " \t\r\n";
+          char *token, *save;
+          token = strtok_r(buf, whitespace, &save);
+          if (token && !strcmp(token, "#define")) {
+
+            // Only parse identifiers that start with "__NR_"
+            token = strtok_r(NULL, whitespace, &save);
+            if (token) {
+              if (strncmp(token, "__NR_", 5)) {
+                continue;
+              }
+              std::string syscallName(token + 5);
+
+              // Parse the value of the symbol. Try to be forgiving in what
+              // we accept, as the file format might change over time.
+              token = strtok_r(NULL, "\r\n", &save);
+              if (token) {
+                // Some values are defined relative to previous values, we
+                // detect these examples by finding an earlier symbol name
+                // followed by a '+' plus character.
+                bool isRelative = false;
+                char *base = strstr(token, baseName.c_str());
+                if (baseNum >= 0 && base) {
+                  base += baseName.length();
+                  while (*base == ' ' || *base == '\t') {
+                    ++base;
+                  }
+                  if (*base == '+') {
+                    isRelative = true;
+                    token = base;
+                  }
+                }
+
+                // Skip any characters that are not part of the syscall number.
+                while (*token < '0' || *token > '9') {
+                  token++;
+                }
+
+                // If we now have a valid datum, enter it into our map.
+                if (*token) {
+                  int sysnum = atoi(token);
+
+                  // Deal with symbols that are defined relative to earlier
+                  // ones.
+                  if (isRelative) {
+                    sysnum += baseNum;
+                  } else {
+                    baseNum  = sysnum;
+                    baseName = syscallName;
+                  }
+
+                  // Keep track of the highest syscall number that we know
+                  // about.
+                  if (sysnum >= numSyscallNames_) {
+                    numSyscallNames_ = sysnum + 1;
+                  }
+
+                  syscallNamesMap_[sysnum] = syscallName;
+                }
+              }
+            }
+          }
+        }
+        fclose(fp);
+        break;
+      }
+    }
+    if (numSyscallNames_) {
+      // We cannot make system calls at the time, when we are looking up
+      // the names. So, copy them into a data structure that can be
+      // accessed without having to allocated memory (i.e. no more STL).
+      syscallNames_ = reinterpret_cast<const char **>(
+          calloc(sizeof(char *), numSyscallNames_));
+      for (std::map<int, std::string>::const_iterator iter =
+               syscallNamesMap_.begin();
+           iter != syscallNamesMap_.end();
+           ++iter) {
+        syscallNames_[iter->first] = iter->second.c_str();
+      }
+    }
+  }
+}
+
+bool Debug::enter() {
+  // Increment the recursion level in TLS storage. This allows us to
+  // make system calls from within our debugging functions, without triggering
+  // additional debugging output.
+  //
+  // This function can be called from both the sandboxed process and from the
+  // trusted process. Only the sandboxed process needs to worry about
+  // recursively calling system calls. The trusted process doesn't intercept
+  // system calls and thus doesn't have this problem. It also doesn't have
+  // a TLS. We explicitly set the segment selector to zero, when in the
+  // trusted process, so that we can avoid tracking recursion levels.
+  int level;
+  #if defined(__x86_64__)
+  asm volatile("mov  %%gs, %0\n"
+               "test %0, %0\n"
+               "jz   1f\n"
+               "movl %%gs:0x1050-0xE0, %0\n"
+               "incl %%gs:0x1050-0xE0\n"
+             "1:\n"
+               : "=r"(level)
+               :
+               : "memory");
+  #elif defined(__i386__)
+  asm volatile("mov  %%fs, %0\n"
+               "test %0, %0\n"
+               "jz   1f\n"
+               "movl %%fs:0x1034-0x58, %0\n"
+               "incl %%fs:0x1034-0x58\n"
+             "1:\n"
+               : "=r"(level)
+               :
+               : "memory");
+  #else
+  #error "Unsupported target platform"
+  #endif
+  return !level;
+}
+
+bool Debug::leave() {
+  // Decrement the recursion level in TLS storage. This allows us to
+  // make system calls from within our debugging functions, without triggering
+  // additional debugging output.
+  //
+  // This function can be called from both the sandboxed process and from the
+  // trusted process. Only the sandboxed process needs to worry about
+  // recursively calling system calls. The trusted process doesn't intercept
+  // system calls and thus doesn't have this problem. It also doesn't have
+  // a TLS. We explicitly set the segment selector to zero, when in the
+  // trusted process, so that we can avoid tracking recursion levels.
+  int level;
+  #if defined(__x86_64__)
+  asm volatile("mov  %%gs, %0\n"
+               "test %0, %0\n"
+               "jz   1f\n"
+               "decl %%gs:0x1050-0xE0\n"
+               "movl %%gs:0x1050-0xE0, %0\n"
+             "1:\n"
+               : "=r"(level)
+               :
+               : "memory");
+  #elif defined(__i386__)
+  asm volatile("mov  %%fs, %0\n"
+               "test %0, %0\n"
+               "jz   1f\n"
+               "decl %%fs:0x1034-0x58\n"
+               "movl %%fs:0x1034-0x58, %0\n"
+             "1:\n"
+               : "=r"(level)
+               :
+               : "memory");
+  #else
+  #error Unsupported target platform
+  #endif
+  return !level;
+}
+
+void Debug::_message(const char* msg) {
+  if (enabled_) {
+    Sandbox::SysCalls sys;
+    size_t len = strlen(msg);
+    if (len && msg[len-1] != '\n') {
+      // Write operations should be atomic, so that we don't interleave
+      // messages from multiple threads. Append a newline, if it is not
+      // already there.
+      char copy[len + 1];
+      memcpy(copy, msg, len);
+      copy[len] = '\n';
+      Sandbox::write(sys, 2, copy, len + 1);
+    } else {
+      Sandbox::write(sys, 2, msg, len);
+    }
+  }
+}
+
+void Debug::message(const char* msg) {
+  if (enabled_) {
+    if (enter()) {
+      _message(msg);
+    }
+    leave();
+  }
+}
+
+void Debug::gettimeofday(long long* tm) {
+  if (tm) {
+    struct timeval tv;
+    #if defined(__i386__)
+    // Zero out the lastSyscallNum, so that we don't try to coalesce
+    // calls to gettimeofday(). For debugging purposes, we need the
+    // exact time.
+    asm volatile("movl $0, %fs:0x102C-0x58");
+    #elif !defined(__x86_64__)
+    #error Unsupported target platform
+    #endif
+    ::gettimeofday(&tv, NULL);
+    *tm = 1000ULL*1000ULL*static_cast<unsigned>(tv.tv_sec) +
+          static_cast<unsigned>(tv.tv_usec);
+  }
+}
+
+void Debug::syscall(long long* tm, int sysnum, const char* msg, int call) {
+  // This function gets called from the system call wrapper. Avoid calling
+  // any library functions that themselves need system calls.
+  if (enabled_) {
+    if (enter() || !tm) {
+      gettimeofday(tm);
+
+      const char *sysname = NULL;
+      if (sysnum >= 0 && sysnum < numSyscallNames_) {
+        sysname = syscallNames_[sysnum];
+      }
+      static const char kUnnamedMessage[] = "Unnamed syscall #";
+      char unnamed[40];
+      if (!sysname) {
+        memcpy(unnamed, kUnnamedMessage, sizeof(kUnnamedMessage) - 1);
+        itoa(unnamed + sizeof(kUnnamedMessage) - 1, sysnum);
+        sysname = unnamed;
+      }
+      #if defined(__NR_socketcall) || defined(__NR_ipc)
+      char extra[40];
+      *extra = '\000';
+      #if defined(__NR_socketcall)
+      if (sysnum == __NR_socketcall) {
+        static const char* socketcall_name[] = {
+          0, "socket", "bind", "connect", "listen", "accept", "getsockname",
+          "getpeername", "socketpair", "send", "recv", "sendto","recvfrom",
+          "shutdown", "setsockopt", "getsockopt", "sendmsg", "recvmsg",
+          "accept4"
+        };
+        if (call >= 1 &&
+            call < (int)(sizeof(socketcall_name)/sizeof(char *))) {
+          strcat(strcpy(extra, " "), socketcall_name[call]);
+        } else {
+          itoa(strcpy(extra, " #") + 2, call);
+        }
+      }
+      #endif
+      #if defined(__NR_ipc)
+      if (sysnum == __NR_ipc) {
+        static const char* ipc_name[] = {
+          0, "semop", "semget", "semctl", "semtimedop", 0, 0, 0, 0, 0, 0,
+          "msgsnd", "msgrcv", "msgget", "msgctl", 0, 0, 0, 0, 0, 0,
+          "shmat", "shmdt", "shmget", "shmctl" };
+        if (call >= 1 && call < (int)(sizeof(ipc_name)/sizeof(char *)) &&
+            ipc_name[call]) {
+          strcat(strcpy(extra, " "), ipc_name[call]);
+        } else {
+          itoa(strcpy(extra, " #") + 2, call);
+        }
+      }
+      #endif
+      #else
+      static const char extra[1] = { 0 };
+      #endif
+      char buf[strlen(sysname) + strlen(extra) + (msg ? strlen(msg) : 0) + 4];
+      strcat(strcat(strcat(strcat(strcpy(buf, sysname), extra), ": "),
+                    msg ? msg : ""), "\n");
+      _message(buf);
+    }
+    leave();
+  }
+}
+
+char* Debug::itoa(char* s, int n) {
+  // Remember return value
+  char *ret   = s;
+
+  // Insert sign for negative numbers
+  if (n < 0) {
+    *s++      = '-';
+    n         = -n;
+  }
+
+  // Convert to decimal (in reverse order)
+  char *start = s;
+  do {
+    *s++      = '0' + (n % 10);
+    n        /= 10;
+  } while (n);
+  *s--        = '\000';
+
+  // Reverse order of digits
+  while (start < s) {
+    char ch   = *s;
+    *s--      = *start;
+    *start++  = ch;
+  }
+
+  return ret;
+}
+
+void Debug::elapsed(long long tm, int sysnum, int call) {
+  if (enabled_) {
+    if (enter()) {
+      // Compute the time that has passed since the system call started.
+      long long delta;
+      gettimeofday(&delta);
+      delta -= tm;
+
+      // Format "Elapsed time: %d.%03dms" without using sprintf().
+      char buf[80];
+      itoa(strrchr(strcpy(buf, "Elapsed time: "), '\000'), delta/1000);
+      delta %= 1000;
+      strcat(buf, delta < 100 ? delta < 10 ? ".00" : ".0" : ".");
+      itoa(strrchr(buf, '\000'), delta);
+      strcat(buf, "ms");
+
+      // Print system call name and elapsed time.
+      syscall(NULL, sysnum, buf, call);
+    }
+    leave();
+  }
+}
+
+} // namespace
+
+#endif // NDEBUG