[Lldb-commits] [lldb] r181904 - Implement "platform process list" on Linux

Daniel Malea daniel.malea at intel.com
Wed May 15 10:54:07 PDT 2013


Author: dmalea
Date: Wed May 15 12:54:07 2013
New Revision: 181904

URL: http://llvm.org/viewvc/llvm-project?rev=181904&view=rev
Log:
Implement "platform process list" on Linux
- read process information from /proc
- resolves llvm.org/pr14541 :)

Patch by Mike Sartain!


Modified:
    lldb/trunk/source/Host/common/Host.cpp
    lldb/trunk/source/Host/linux/Host.cpp

Modified: lldb/trunk/source/Host/common/Host.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Host/common/Host.cpp?rev=181904&r1=181903&r2=181904&view=diff
==============================================================================
--- lldb/trunk/source/Host/common/Host.cpp (original)
+++ lldb/trunk/source/Host/common/Host.cpp Wed May 15 12:54:07 2013
@@ -1207,14 +1207,14 @@ Host::GetEffectiveGroupID ()
     return getegid();
 }
 
-#if !defined (__APPLE__)
+#if !defined (__APPLE__) && !defined(__linux__)
 uint32_t
 Host::FindProcesses (const ProcessInstanceInfoMatch &match_info, ProcessInstanceInfoList &process_infos)
 {
     process_infos.Clear();
     return process_infos.GetSize();
 }
-#endif
+#endif // #if !defined (__APPLE__) && !defined(__linux__)
 
 #if !defined (__APPLE__) && !defined (__FreeBSD__) && !defined(__linux__)
 bool

Modified: lldb/trunk/source/Host/linux/Host.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Host/linux/Host.cpp?rev=181904&r1=181903&r2=181904&view=diff
==============================================================================
--- lldb/trunk/source/Host/linux/Host.cpp (original)
+++ lldb/trunk/source/Host/linux/Host.cpp Wed May 15 12:54:07 2013
@@ -12,9 +12,9 @@
 #include <sys/utsname.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <dirent.h>
 #include <fcntl.h>
 
-
 // C++ Includes
 // Other libraries and framework includes
 // Project includes
@@ -28,56 +28,173 @@
 using namespace lldb;
 using namespace lldb_private;
 
+typedef enum ProcessStateFlags
+{
+    eProcessStateRunning           = (1u << 0), // Running
+    eProcessStateSleeping          = (1u << 1), // Sleeping in an interruptible wait
+    eProcessStateWaiting           = (1u << 2), // Waiting in an uninterruptible disk sleep
+    eProcessStateZombie            = (1u << 3), // Zombie
+    eProcessStateTracedOrStopped   = (1u << 4), // Traced or stopped (on a signal)
+    eProcessStatePaging            = (1u << 5)  // Paging
+} ProcessStateFlags;
+
+typedef struct ProcessStatInfo
+{
+    lldb::pid_t ppid;           // Parent Process ID
+    uint32_t fProcessState;     // ProcessStateFlags
+} ProcessStatInfo;
+
+// Get the process info with additional information from /proc/$PID/stat (like process state, and tracer pid).
+static bool GetProcessAndStatInfo (lldb::pid_t pid, ProcessInstanceInfo &process_info, ProcessStatInfo &stat_info, lldb::pid_t &tracerpid);
+
 namespace
 {
 
 lldb::DataBufferSP
-ReadProcPseudoFile(lldb::pid_t pid, const char *name)
+ReadProcPseudoFile (lldb::pid_t pid, const char *name)
 {
-    static const size_t path_size = 128;
-    static char path[path_size];
-    lldb::DataBufferSP buf_sp;
-
     int fd;
+    char path[PATH_MAX];
+
+    // Make sure we've got a nil terminated buffer for all the folks calling
+    // GetBytes() directly off our returned DataBufferSP if we hit an error.
+    lldb::DataBufferSP buf_sp (new DataBufferHeap(1, 0));
 
     // Ideally, we would simply create a FileSpec and call ReadFileContents.
     // However, files in procfs have zero size (since they are, in general,
     // dynamically generated by the kernel) which is incompatible with the
-    // current ReadFileContents implementation.  Therefore we simply stream the
+    // current ReadFileContents implementation. Therefore we simply stream the
     // data into a DataBuffer ourselves.
-    if (snprintf(path, path_size, "/proc/%" PRIu64 "/%s", pid, name) < 0)
-        return buf_sp;
+    if (snprintf (path, PATH_MAX, "/proc/%" PRIu64 "/%s", pid, name) > 0)
+    {
+        if ((fd = open (path, O_RDONLY, 0)) >= 0)
+        {
+            size_t bytes_read = 0;
+            std::unique_ptr<DataBufferHeap> buf_ap(new DataBufferHeap(1024, 0));
+
+            for (;;) 
+            {
+                size_t avail = buf_ap->GetByteSize() - bytes_read;
+                ssize_t status = read (fd, buf_ap->GetBytes() + bytes_read, avail);
+
+                if (status < 0) 
+                    break;
+
+                if (status == 0) 
+                {
+                    buf_ap->SetByteSize (bytes_read);
+                    buf_sp.reset (buf_ap.release());
+                    break;
+                }
+
+                bytes_read += status;
+
+                if (avail - status == 0)
+                    buf_ap->SetByteSize (2 * buf_ap->GetByteSize());
+            }
+
+            close (fd);
+        }
+    }
 
-    if ((fd = open(path, O_RDONLY, 0)) < 0)
-        return buf_sp;
+    return buf_sp;
+}
+
+} // anonymous namespace
 
-    size_t bytes_read = 0;
-    std::unique_ptr<DataBufferHeap> buf_ap(new DataBufferHeap(1024, 0));
-    for (;;) 
+static bool
+ReadProcPseudoFileStat (lldb::pid_t pid, ProcessStatInfo& stat_info)
+{
+    // Read the /proc/$PID/stat file.
+    lldb::DataBufferSP buf_sp = ReadProcPseudoFile (pid, "stat");
+
+    // The filename of the executable is stored in parenthesis right after the pid. We look for the closing
+    // parenthesis for the filename and work from there in case the name has something funky like ')' in it.
+    const char *filename_end = strrchr ((const char *)buf_sp->GetBytes(), ')');
+    if (filename_end)
     {
-        size_t avail = buf_ap->GetByteSize() - bytes_read;
-        ssize_t status = read(fd, buf_ap->GetBytes() + bytes_read, avail);
+        char state = '\0';
+        int ppid = LLDB_INVALID_PROCESS_ID;
 
-        if (status < 0) 
-            break;
+        // Read state and ppid.
+        sscanf (filename_end + 1, " %c %d", &state, &ppid);
 
-        bytes_read += status;
+        stat_info.ppid = ppid;
 
-        if (status == 0) 
+        switch (state)
         {
-            buf_ap->SetByteSize(bytes_read);
-            buf_sp.reset(buf_ap.release());
-            break;
+            case 'R':
+                stat_info.fProcessState |= eProcessStateRunning;
+                break;
+            case 'S':
+                stat_info.fProcessState |= eProcessStateSleeping;
+                break;
+            case 'D':
+                stat_info.fProcessState |= eProcessStateWaiting;
+                break;
+            case 'Z':
+                stat_info.fProcessState |= eProcessStateZombie;
+                break;
+            case 'T':
+                stat_info.fProcessState |= eProcessStateTracedOrStopped;
+                break;
+            case 'W':
+                stat_info.fProcessState |= eProcessStatePaging;
+                break;
         }
 
-        if (avail - status == 0)
-            buf_ap->SetByteSize(2 * buf_ap->GetByteSize());
+        return true;
     }
 
-    return buf_sp;
+    return false;
 }
 
-} // anonymous namespace
+static void
+GetLinuxProcessUserAndGroup (lldb::pid_t pid, ProcessInstanceInfo &process_info, lldb::pid_t &tracerpid)
+{
+    tracerpid = 0;
+    uint32_t rUid = UINT32_MAX;     // Real User ID
+    uint32_t eUid = UINT32_MAX;     // Effective User ID
+    uint32_t rGid = UINT32_MAX;     // Real Group ID
+    uint32_t eGid = UINT32_MAX;     // Effective Group ID
+
+    // Read the /proc/$PID/status file and parse the Uid:, Gid:, and TracerPid: fields.
+    lldb::DataBufferSP buf_sp = ReadProcPseudoFile (pid, "status");
+
+    static const char uid_token[] = "Uid:";
+    char *buf_uid = strstr ((char *)buf_sp->GetBytes(), uid_token);
+    if (buf_uid)
+    {
+        // Real, effective, saved set, and file system UIDs. Read the first two.
+        buf_uid += sizeof(uid_token);
+        rUid = strtol (buf_uid, &buf_uid, 10);
+        eUid = strtol (buf_uid, &buf_uid, 10);
+    }
+
+    static const char gid_token[] = "Gid:";
+    char *buf_gid = strstr ((char *)buf_sp->GetBytes(), gid_token);
+    if (buf_gid)
+    {
+        // Real, effective, saved set, and file system GIDs. Read the first two.
+        buf_gid += sizeof(gid_token);
+        rGid = strtol (buf_gid, &buf_gid, 10);
+        eGid = strtol (buf_gid, &buf_gid, 10);
+    }
+
+    static const char tracerpid_token[] = "TracerPid:";
+    char *buf_tracerpid = strstr((char *)buf_sp->GetBytes(), tracerpid_token);
+    if (buf_tracerpid)
+    {
+        // Tracer PID. 0 if we're not being debugged.
+        buf_tracerpid += sizeof(tracerpid_token);
+        tracerpid = strtol (buf_tracerpid, &buf_tracerpid, 10);
+    }
+
+    process_info.SetUserID (rUid);
+    process_info.SetEffectiveUserID (eUid);
+    process_info.SetGroupID (rGid);
+    process_info.SetEffectiveGroupID (eGid);
+}
 
 bool
 Host::GetOSVersion(uint32_t &major,
@@ -108,12 +225,79 @@ Host::GetAuxvData(lldb_private::Process
     return ReadProcPseudoFile(process->GetID(), "auxv");
 }
 
+static bool
+IsDirNumeric(const char *dname)
+{
+    for (; *dname; dname++)
+    {
+        if (!isdigit (*dname))
+            return false;
+    }
+    return true;
+}
 
-bool
-Host::GetProcessInfo (lldb::pid_t pid, ProcessInstanceInfo &process_info)
+uint32_t
+Host::FindProcesses (const ProcessInstanceInfoMatch &match_info, ProcessInstanceInfoList &process_infos)
+{
+    static const char procdir[] = "/proc/";
+
+    DIR *dirproc = opendir (procdir);
+    if (dirproc)
+    {
+        struct dirent *direntry = NULL;
+        const uid_t our_uid = getuid();
+        const lldb::pid_t our_pid = getpid();
+        bool all_users = match_info.GetMatchAllUsers();
+
+        while ((direntry = readdir (dirproc)) != NULL)
+        {
+            if (direntry->d_type != DT_DIR || !IsDirNumeric (direntry->d_name))
+                continue;
+
+            lldb::pid_t pid = atoi (direntry->d_name);
+
+            // Skip this process.
+            if (pid == our_pid)
+                continue;
+
+            lldb::pid_t tracerpid;
+            ProcessStatInfo stat_info;
+            ProcessInstanceInfo process_info;
+
+            if (!GetProcessAndStatInfo (pid, process_info, stat_info, tracerpid))
+                continue;
+
+            // Skip if process is being debugged.
+            if (tracerpid != 0)
+                continue;
+
+            // Skip zombies.
+            if (stat_info.fProcessState & eProcessStateZombie)
+                continue;
+
+            // Check for user match if we're not matching all users and not running as root.
+            if (!all_users && (our_uid != 0) && (process_info.GetUserID() != our_uid))
+                continue;
+
+            if (match_info.Matches (process_info))
+            {
+                process_infos.Append (process_info);
+            }
+        }
+
+        closedir (dirproc);
+    }
+
+    return process_infos.GetSize();
+}
+
+static bool
+GetProcessAndStatInfo (lldb::pid_t pid, ProcessInstanceInfo &process_info, ProcessStatInfo &stat_info, lldb::pid_t &tracerpid)
 {
+    tracerpid = 0;
     process_info.Clear();
-    process_info.SetProcessID(pid);
+    ::memset (&stat_info, 0, sizeof(stat_info));
+    stat_info.ppid = LLDB_INVALID_PROCESS_ID;
 
     // Architecture is intentionally omitted because that's better resolved
     // in other places (see ProcessPOSIX::DoAttachWithID().
@@ -121,19 +305,26 @@ Host::GetProcessInfo (lldb::pid_t pid, P
     // Use special code here because proc/[pid]/exe is a symbolic link.
     char link_path[PATH_MAX];
     char exe_path[PATH_MAX] = "";
-    if (snprintf(link_path, PATH_MAX, "/proc/%" PRIu64 "/exe", pid) > 0)
+    if (snprintf (link_path, PATH_MAX, "/proc/%" PRIu64 "/exe", pid) <= 0)
+        return false;
+
+    ssize_t len = readlink (link_path, exe_path, sizeof(exe_path) - 1);
+    if (len <= 0)
+        return false;
+
+    // readlink does not append a null byte.
+    exe_path[len] = 0;
+
+    // If the binary has been deleted, the link name has " (deleted)" appended.
+    //  Remove if there.
+    static const ssize_t deleted_len = strlen(" (deleted)");
+    if (len > deleted_len &&
+        !strcmp(exe_path + len - deleted_len, " (deleted)"))
     {
-        ssize_t len = readlink(link_path, exe_path, sizeof(exe_path) - 1);
-        if (len > 0)
-            exe_path[len] = 0;
-
-        static const ssize_t deleted_len = strlen(" (deleted)");
-        if (len > deleted_len &&
-            !strcmp(exe_path + len - deleted_len, " (deleted)"))
-        {
-            exe_path[len - deleted_len] = 0;
-        }
+        exe_path[len - deleted_len] = 0;
     }
+
+    process_info.SetProcessID(pid);
     process_info.GetExecutableFile().SetFile(exe_path, false);
 
     lldb::DataBufferSP buf_sp;
@@ -166,11 +357,27 @@ Host::GetProcessInfo (lldb::pid_t pid, P
         next_arg += strlen(next_arg) + 1;
     }
 
-    // FIXME: Parse /proc/<pid>/status to get uid, gid, euid, egid and parent_pid
+    // Read /proc/$PID/stat to get our parent pid.
+    if (ReadProcPseudoFileStat (pid, stat_info))
+    {
+        process_info.SetParentProcessID (stat_info.ppid);
+    }
+
+    // Get User and Group IDs and get tracer pid.
+    GetLinuxProcessUserAndGroup (pid, process_info, tracerpid);
 
     return true;
 }
 
+bool
+Host::GetProcessInfo (lldb::pid_t pid, ProcessInstanceInfo &process_info)
+{
+    lldb::pid_t tracerpid;
+    ProcessStatInfo stat_info;
+
+    return GetProcessAndStatInfo (pid, process_info, stat_info, tracerpid);
+}
+
 void
 Host::ThreadCreated (const char *thread_name)
 {





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