Proposal: Use /usr/bin/top in about:memory...

chrome/browser/process_info_snapshot_mac.cc

Index: chrome/browser/process_info_snapshot_mac.cc
===================================================================
--- chrome/browser/process_info_snapshot_mac.cc	(revision 70404)
+++ chrome/browser/process_info_snapshot_mac.cc	(working copy)
@@ -4,17 +4,17 @@
 
 #include "chrome/browser/process_info_snapshot.h"
 
+#include <sys/sysctl.h>
+
 #include <sstream>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
+#include "base/sys_info.h"
 #include "base/threading/thread.h"
 
-// Implementation for the Mac; calls '/bin/ps' for information when
-// |Sample()| is called.
-
 // Default constructor.
 ProcessInfoSnapshot::ProcessInfoSnapshot() { }
 
@@ -25,30 +25,111 @@
 
 const size_t ProcessInfoSnapshot::kMaxPidListSize = 1000;
 
-// Capture the information by calling '/bin/ps'.
-// Note: we ignore the "tsiz" (text size) display option of ps because it's
-// always zero (tested on 10.5 and 10.6).
-bool ProcessInfoSnapshot::Sample(std::vector<base::ProcessId> pid_list) {
-  const char* kPsPathName = "/bin/ps";
-  Reset();
+static bool GetKInfoForProcessID(pid_t pid, kinfo_proc* kinfo) {
+  int mib[] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
+  size_t len = sizeof(*kinfo);
+  if (sysctl(mib, arraysize(mib), kinfo, &len, NULL, 0) != 0) {
+    PLOG(ERROR) << "sysctl() for KERN_PROC";
+    return false;
+  }
+  return true;
+}
 
-  // Nothing to do if no PIDs given.
-  if (pid_list.size() == 0)
-    return true;
-  if (pid_list.size() > kMaxPidListSize) {
-    // The spec says |pid_list| *must* not have more than this many entries.
+static bool GetExecutableNameForProcessID(
+    pid_t pid,
+    std::string* executable_name) {
+  if (!executable_name) {
     NOTREACHED();
     return false;
   }
 
+  static int s_arg_max = 0;
+  if (s_arg_max == 0) {
+    int mib[] = {CTL_KERN, KERN_ARGMAX};
+    size_t size = sizeof(s_arg_max);
+    if (sysctl(mib, arraysize(mib), &s_arg_max, &size, NULL, 0) != 0)
+      PLOG(ERROR) << "sysctl() for KERN_ARGMAX";
+  }
+
+  if (s_arg_max == 0)
+    return false;
+
+  int mib[] = {CTL_KERN, KERN_PROCARGS, pid};
+  size_t size = s_arg_max;
+  executable_name->resize(s_arg_max + 1);
+  if (sysctl(mib, arraysize(mib), &(*executable_name)[0],
+             &size, NULL, 0) != 0) {
+    // Don't log the error since it's normal for this to fail.
+    return false;
+  }
+
+  // KERN_PROCARGS returns multiple NULL terminated strings. Truncate
+  // executable_name to just the first string.
+  size_t end_pos = executable_name->find('\0');
+  if (end_pos == std::string::npos) {
+    return false;
+  }
+
+  executable_name->resize(end_pos);
+  return true;
+}
+
+// Converts a byte unit such as 'K' or 'M' into the scale for the unit.
+// The scale can then be used to calculate the number of bytes in a value.
+// The units are based on humanize_number(). See:
+// http://www.opensource.apple.com/source/libutil/libutil-21/humanize_number.c
+static bool ConvertByteUnitToScale(char unit, uint64_t* out_scale) {
+  int shift = 0;
+  switch (unit) {
+    case 'B':
+      shift = 0;
+      break;
+    case 'K':
+    case 'k':
+      shift = 1;
+      break;
+    case 'M':
+      shift = 2;
+      break;
+    case 'G':
+      shift = 3;
+      break;
+    case 'T':
+      shift = 4;
+      break;
+    case 'P':
+      shift = 5;
+      break;
+    case 'E':
+      shift = 6;
+      break;
+    default:
+      return false;
+  }
+
+  uint64_t scale = 1;
+  for (int i = 0; i < shift; i++)
+    scale *= 1024;
+  *out_scale = scale;
+
+  return true;
+}
+
+// Capture the information by calling '/bin/ps'.
+// Note: we ignore the "tsiz" (text size) display option of ps because it's
+// always zero (tested on 10.5 and 10.6).
+static bool GetProcessMemoryInfoUsingPS(
+    const std::vector<base::ProcessId>& pid_list,
+    std::map<int,ProcessInfoSnapshot::ProcInfoEntry>& proc_info_entries) {
+  const char kPsPathName[] = "/bin/ps";
   std::vector<std::string> argv;
   argv.push_back(kPsPathName);
-  // Get PID, PPID, (real) UID, effective UID, resident set size, virtual memory
-  // size, and command.
+
+  // Get resident set size, virtual memory size.
   argv.push_back("-o");
-  argv.push_back("pid=,ppid=,ruid=,uid=,rss=,vsz=,comm=");
+  argv.push_back("pid=,rss=,vsz=");

[Mark Mentovai, 2011/01/06 21:50:04]

Why did you take the ruid and uid out for ps?

[sail, 2011/01/06 23:29:21]

I'm trying to use kinfo.kp_eproc.e_pcred.p_ruid and
kinfo.kp_eproc.e_ucred.cr_uid instead.

Maybe these items don't return the correct value if the target process is
running as root.

Dropping support for ruid and gathering that information only from ps/top seems
fine to me. Want me to do that?

   // Only display the specified PIDs.
-  for (std::vector<base::ProcessId>::iterator it = pid_list.begin();
+  for (std::vector<base::ProcessId>::const_iterator it = pid_list.begin();
       it != pid_list.end(); ++it) {
     argv.push_back("-p");
     argv.push_back(base::Int64ToString(static_cast<int64>(*it)));
@@ -67,20 +148,21 @@
 
   // Process lines until done.
   while (true) {
-    ProcInfoEntry proc_info;
-
     // The format is as specified above to ps (see ps(1)):
-    //   "-o pid=,ppid=,ruid=,uid=,rss=,vsz=,comm=".
+    //   "-o pid=,rss=,vsz=".
     // Try to read the PID; if we get it, we should be able to get the rest of
     // the line.
-    in >> proc_info.pid;
+    pid_t pid;
+    in >> pid;
     if (in.eof())
       break;
-    in >> proc_info.ppid;
-    in >> proc_info.uid;
-    in >> proc_info.euid;
+
+    ProcessInfoSnapshot::ProcInfoEntry proc_info = proc_info_entries[pid];
+    proc_info.pid = pid;
     in >> proc_info.rss;
     in >> proc_info.vsize;
+    proc_info.rss *= 1024;                // Convert from kilobytes to bytes.
+    proc_info.vsize *= 1024;
     in.ignore(1, ' ');                    // Eat the space.
     std::getline(in, proc_info.command);  // Get the rest of the line.
     if (!in.good()) {
@@ -88,24 +170,225 @@
       return false;
     }
 
-    // Make sure the new PID isn't already in our list.
-    if (proc_info_entries_.find(proc_info.pid) != proc_info_entries_.end()) {
-      LOG(ERROR) << "Duplicate PID in output from " << kPsPathName << ".";
-      return false;
-    }
-
     if (!proc_info.pid || ! proc_info.vsize) {
       LOG(WARNING) << "Invalid data from " << kPsPathName << ".";
       return false;
     }
 
     // Record the process information.
-    proc_info_entries_[proc_info.pid] = proc_info;
+    proc_info_entries[proc_info.pid] = proc_info;
   }
 
   return true;
 }
 
+static bool GetProcessMemoryInfoUsingTop(
+    std::map<int,ProcessInfoSnapshot::ProcInfoEntry>& proc_info_entries) {
+  const char kTopPathName[] = "/usr/bin/top";
+  std::vector<std::string> argv;
+  argv.push_back(kTopPathName);
+
+  // -stats tells top to print just the given fields as ordered.
+  argv.push_back("-stats");
+  argv.push_back("pid,"    // Process ID
+                 "rsize,"  // Resident memory
+                 "rshrd,"  // Resident shared memory
+                 "rprvt,"  // Resident private memory
+                 "vsize"); // Total virtual memory

[Mark Mentovai, 2011/01/06 21:50:04]

You can do uid (which gives you effective user ID), but top doesn’t seem to have
anything to give you the real user ID. That’s clearly why your test is
failing—it doesn’t have anything to do with “dropping privileges.”

Maybe it’s best to collect [effective] uid (since it seems like we can do it in
all cases), never collect ruid (even when we can get it?), and just call that
the limit of the interface on the Mac?

+  // Run top in logging (non-interactive) mode.
+  argv.push_back("-l");
+  argv.push_back("1");
+

[Mark Mentovai, 2011/01/06 21:50:04]

Add |-s 0| too, to prevent top from sleeping for one second after dumping its
one and only sample.

[sail, 2011/01/06 23:29:21]

Wow, I don't know how I missed that. Thanks so much. This makes things a lot
faster.

+  std::string output;
+  CommandLine command_line(argv);
+  // Limit output read to a megabyte for safety.
+  if (!base::GetAppOutputRestricted(command_line, &output, 1024 * 1024)) {
+    LOG(ERROR) << "Failure running " << kTopPathName << " to acquire data.";
+    return false;
+  }
+
+  // Process lines until done. Lines should look something like this:
+  // PID    RSIZE  RSHRD  RPRVT  VSIZE
+  // 58539  1276K+ 336K+  740K+  2378M+
+  // 58485  1888K+ 592K+  1332K+ 2383M+
+  std::istringstream top_in(output, std::istringstream::in);
+  std::string line;
+  while (std::getline(top_in, line)) {
+    std::istringstream in(line, std::istringstream::in);
+
+    // Try to read the PID.
+    pid_t pid;
+    in >> pid;
+    if (in.fail())
+      continue;
+
+    // Make sure that caller is interested in this process.
+    if (proc_info_entries.find(pid) == proc_info_entries.end())
+      continue;
+
+    // Skip the - or + sign that top puts after the pid.
+    in.get();
+
+    uint64_t values[4];
+    size_t i;
+    for (i = 0; i < arraysize(values); i++) {
+      in >> values[i];
+      if (in.fail())
+        break;
+      std::string unit;
+      in >> unit;
+      if (in.fail())
+        break;
+
+      if (unit.size() == 0)
+        break;
+
+      uint64_t scale;
+      if (!ConvertByteUnitToScale(unit[0], &scale))
+        break;
+      values[i] *= scale;
+    }
+    if (i != arraysize(values))
+      continue;
+
+    ProcessInfoSnapshot::ProcInfoEntry proc_info = proc_info_entries[pid];
+    proc_info.rss = values[0];
+    proc_info.rshrd = values[1];
+    proc_info.rprvt = values[2];
+    proc_info.vsize = values[3];
+    // Record the process information.
+    proc_info_entries[proc_info.pid] = proc_info;
+  }
+
+  return true;
+}
+
+static bool GetProcessMemoryInfoUsingTop_10_5(
+    std::map<int,ProcessInfoSnapshot::ProcInfoEntry>& proc_info_entries) {
+  const char kTopPathName[] = "/usr/bin/top";
+  std::vector<std::string> argv;
+  argv.push_back(kTopPathName);
+
+  // -p tells top to print just the given fields as ordered.
+  argv.push_back("-p");
+  argv.push_back("^aaaaaaaaaaaaaaaaaaaa "  // Process ID (PID)
+                 "^jjjjjjjjjjjjjjjjjjjj "  // Resident memory (RSIZE)
+                 "^iiiiiiiiiiiiiiiiiiii "  // Resident shared memory (RSHRD)
+                 "^hhhhhhhhhhhhhhhhhhhh "  // Resident private memory (RPRVT)
+                 "^llllllllllllllllllll"); // Total virtual memory (VSIZE)
+  // Run top in logging (non-interactive) mode.
+  argv.push_back("-l");
+  argv.push_back("1");
+

[Mark Mentovai, 2011/01/06 21:50:04]

10.5 top seems to exit immediately even without -s 0, but you may wish to
include it anyway for consistency.

[sail, 2011/01/06 23:29:21]

Done.

+  std::string output;
+  CommandLine command_line(argv);
+  // Limit output read to a megabyte for safety.
+  if (!base::GetAppOutputRestricted(command_line, &output, 1024 * 1024)) {
+    LOG(ERROR) << "Failure running " << kTopPathName << " to acquire data.";
+    return false;
+  }
+
+  // Process lines until done. Lines should look something like this:
+  // PID      RSIZE     RSHRD     RPRVT     VSIZE
+  // 16943    815104    262144    290816    18489344
+  // 16922    954368    720896    278528    18976768
+  std::istringstream top_in(output, std::istringstream::in);
+  std::string line;
+  while (std::getline(top_in, line)) {
+    std::istringstream in(line, std::istringstream::in);
+
+    // Try to read the PID.
+    pid_t pid;
+    in >> pid;
+    if (in.fail())
+      continue;
+
+    // Make sure that caller is interested in this process.
+    if (proc_info_entries.find(pid) == proc_info_entries.end())
+      continue;
+
+    uint64_t values[4];
+    size_t i;
+    for (i = 0; i < arraysize(values); i++) {
+      in >> values[i];
+      if (in.fail())
+        break;
+    }
+    if (i != arraysize(values))
+      continue;
+
+    ProcessInfoSnapshot::ProcInfoEntry proc_info = proc_info_entries[pid];
+    proc_info.rss = values[0];
+    proc_info.rshrd = values[1];
+    proc_info.rprvt = values[2];
+    proc_info.vsize = values[3];
+    // Record the process information.
+    proc_info_entries[proc_info.pid] = proc_info;
+  }
+
+  return true;
+}
+
+
+bool ProcessInfoSnapshot::Sample(std::vector<base::ProcessId> pid_list) {
+  Reset();
+
+  // Nothing to do if no PIDs given.
+  if (pid_list.size() == 0)
+    return true;
+  if (pid_list.size() > kMaxPidListSize) {
+    // The spec says |pid_list| *must* not have more than this many entries.
+    NOTREACHED();
+    return false;
+  }
+
+  // Get basic process info from KERN_PROC.
+  for (std::vector<base::ProcessId>::iterator it = pid_list.begin();
+       it != pid_list.end(); ++it) {
+    ProcInfoEntry proc_info;
+    proc_info.pid = *it;
+
+    kinfo_proc kinfo;
+    if (!GetKInfoForProcessID(*it, &kinfo))
+      return false;
+
+    proc_info.ppid = kinfo.kp_eproc.e_ppid;
+    proc_info.uid = kinfo.kp_eproc.e_pcred.p_ruid;
+    proc_info.euid = kinfo.kp_eproc.e_ucred.cr_uid;
+    // Note, p_comm is truncated to 16 characters.
+    proc_info.command = kinfo.kp_proc.p_comm;
+    proc_info_entries_[*it] = proc_info;
+  }
+
+  // Use KERN_PROCARGS to get the full executable name. This may fail if this
+  // process doesn't have privileges to inspect the target process.
+  for (std::vector<base::ProcessId>::iterator it = pid_list.begin();
+       it != pid_list.end(); ++it) {
+    std::string exectuable_name;
+    if (GetExecutableNameForProcessID(*it, &exectuable_name)) {
+      ProcInfoEntry proc_info = proc_info_entries_[*it];
+      proc_info.command = exectuable_name;
+    }
+  }
+
+  // Get memory information using top.
+  bool memory_info_success = false;
+  int32 major, minor, bugfix;
+  base::SysInfo::OperatingSystemVersionNumbers(&major, &minor, &bugfix);
+  if (major == 10 && minor == 5)
+    memory_info_success = GetProcessMemoryInfoUsingTop_10_5(proc_info_entries_);
+  else if ((major == 10 && minor >= 6) || major > 10)
+    memory_info_success = GetProcessMemoryInfoUsingTop(proc_info_entries_);
+
+  // If top didn't work then fall back to ps.
+  if (!memory_info_success) {
+    memory_info_success = GetProcessMemoryInfoUsingPS(pid_list,
+                                                      proc_info_entries_);
+  }
+
+  return memory_info_success;
+}
+
 // Clear all the stored information.
 void ProcessInfoSnapshot::Reset() {
   proc_info_entries_.clear();
@@ -139,7 +422,7 @@
     return false;
   }
 
-  usage->priv = proc_info.vsize;
+  usage->priv = proc_info.vsize / 1024;
   usage->mapped = 0;
   usage->image = 0;
   return true;
@@ -163,8 +446,8 @@
     return false;
   }
 
-  ws_usage->priv = 0;
-  ws_usage->shareable = proc_info.rss;
-  ws_usage->shared = 0;
+  ws_usage->priv = proc_info.rprvt / 1024;
+  ws_usage->shareable = proc_info.rss / 1024;
+  ws_usage->shared = proc_info.rshrd / 1024;
   return true;
 }