support runtime setting of srcmounts. closes #12

README.md

@@ -97,10 +97,15 @@ There is a pseudo file available at the mountpoint which allows for the runtime
 
 Even if xattrs are disabled the [{list,get,set}xattrs](http://linux.die.net/man/2/listxattr) calls will still work.
 
-The keys are **user.mergerfs.action**, **user.mergerfs.create**, and **user.mergerfs.search**.
+The keys are:
+* user.mergerfs.srcmounts
+* user.mergerfs.action
+* user.mergerfs.create
+* user.mergerfs.search
 
 ```
 [trapexit:/tmp/mount] $ xattr -l .mergerfs
+user.mergerfs.srcmounts: /tmp/a:/tmp/b
 user.mergerfs.action: ff
 user.mergerfs.create: epmfs
 user.mergerfs.search: ff
@@ -111,9 +116,34 @@ ff
 [trapexit:/tmp/mount] $ xattr -w user.mergerfs.action ffwp .mergerfs
 [trapexit:/tmp/mount] $ xattr -p user.mergerfs.action .mergerfs
 ffwp
+
+[trapexit:/tmp/mount] $ xattr -w user.mergerfs.srcmounts +/tmp/c .mergerfs
+[trapexit:/tmp/mount] $ xattr -p user.mergerfs.srcmounts .mergerfs
+/tmp/a:/tmp/b:/tmp/c
+
+[trapexit:/tmp/mount] $ xattr -w user.mergerfs.srcmounts =/tmp/c .mergerfs
+[trapexit:/tmp/mount] $ xattr -p user.mergerfs.srcmounts .mergerfs
+/tmp/c
+
+[trapexit:/tmp/mount] $ xattr -w user.mergerfs.srcmounts '+</tmp/a:/tmp/b' .mergerfs
+[trapexit:/tmp/mount] $ xattr -p user.mergerfs.srcmounts .mergerfs
+/tmp/a:/tmp/b:/tmp/c
 ```
 
-#### mergerfs xattrs ####
+For **user.mergerfs.srcmounts** there are several instructions available for manipulating the list. The value provided is just as the value used at mount time. A colon (':') delimited list of full path globs.
+
+| Instruction | Description |
+|--------------|-------------|
+| +[list] | append |
+| +<[list] | prepend |
+| +>[list] | append |
+| -[list] | remove all values provided |
+| -< | remove first in list |
+| -> | remove last in list |
+| =[list] | set |
+| [list] | set |
+
+#### mergerfs file xattrs ####
 
 While they won't show up when using [listxattr](http://linux.die.net/man/2/listxattr) mergerfs offers a number of special xattrs to query information about the files served. To access the values you will need to issue a [getxattr](http://linux.die.net/man/2/getxattr) for one of the following:
 
@@ -124,5 +154,7 @@ While they won't show up when using [listxattr](http://linux.die.net/man/2/listx
 [trapexit:/tmp/mount] $ ls
 A B C
 [trapexit:/tmp/mount] $ xattr -p user.mergerfs.fullpath A
-/mnt/full/path/to/A
+/mnt/a/full/path/to/A
+[trapexit:/tmp/mount] $ xattr -p user.mergerfs.basepath A
+/mnt/a
 ```

src/access.cpp

@@ -37,7 +37,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -73,6 +73,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _access(*config.search,
                      config.srcmounts,

src/chmod.cpp

@@ -31,7 +31,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -76,6 +76,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
       const config::Config      &config = config::get();
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _chmod(*config.action,
                     config.srcmounts,

src/chown.cpp

@@ -32,7 +32,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -79,6 +79,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _chown(*config.action,
                     config.srcmounts,

src/config.cpp

@@ -24,23 +24,34 @@
 
 #include <fuse.h>
 
-#include <sstream>
+#include <string>
+#include <vector>
 
 #include <unistd.h>
 #include <sys/stat.h>
 
 #include "config.hpp"
+#include "rwlock.hpp"
+#include "fs.hpp"
+
+using std::string;
+using std::vector;
 
 namespace mergerfs
 {
   namespace config
   {
     Config::Config()
-      : action(policies[0]),
-        create(policies[1]),
-        search(policies[2]),
+      : destmount(),
+        srcmounts(),
+        srcmountslock(),
+        action(policies[Category::Enum::action]),
+        create(policies[Category::Enum::create]),
+        search(policies[Category::Enum::search]),
         controlfile("/.mergerfs")
     {
+      pthread_rwlock_init(&srcmountslock,NULL);
+
       action = &Policy::ff;
       create = &Policy::epmfs;
       search = &Policy::ff;

src/config.hpp

@@ -45,6 +45,7 @@ namespace mergerfs
     public:
       std::string              destmount;
       std::vector<std::string> srcmounts;
+      mutable pthread_rwlock_t srcmountslock;
 
       const Policy *policies[Category::Enum::END];
       const Policy *&action;

src/create.cpp

@@ -36,7 +36,7 @@
 #include "ugid.hpp"
 #include "fileinfo.hpp"
 #include "fs.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -94,6 +94,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _create(*config.search,
                      *config.create,

src/fs.cpp

@@ -38,30 +38,18 @@
 #include <sys/statvfs.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <glob.h>
+#include <fnmatch.h>
 
 #include "fs.hpp"
 #include "xattr.hpp"
+#include "str.hpp"
 
 using std::string;
 using std::vector;
 using std::map;
 using std::istringstream;
 
-template<typename Container>
-Container&
-split(Container                                  &result,
-      const typename Container::value_type       &s,
-      typename Container::value_type::value_type  delimiter)
-{
-  string        str;
-  istringstream ss(s);
-
-  while(std::getline(ss,str,delimiter))
-    result.push_back(str);
-
-  return result;
-}
-
 template <typename Iter>
 Iter
 random_element(Iter begin,
@@ -208,7 +196,7 @@ namespace fs
     if(rv != -1)
       {
         string tmp(attrs.begin(),attrs.end());
-        split(attrvector,tmp,'\0');
+        str::split(attrvector,tmp,'\0');
       }
 
     return rv;
@@ -453,6 +441,52 @@ namespace fs
     return (errno = 0);
   }
 
+  void
+  glob(const vector<string> &patterns,
+       vector<string>       &strs)
+  {
+    int flags;
+    glob_t gbuf;
+
+    flags = 0;
+    for(size_t i = 0; i < patterns.size(); i++)
+      {
+        glob(patterns[i].c_str(),flags,NULL,&gbuf);
+        flags = GLOB_APPEND;
+      }
+
+    for(size_t i = 0; i < gbuf.gl_pathc; ++i)
+      strs.push_back(gbuf.gl_pathv[i]);
+
+    globfree(&gbuf);
+  }
+
+  void
+  erase_fnmatches(const vector<string> &patterns,
+                  vector<string>       &strs)
+  {
+    vector<string>::iterator si;
+    vector<string>::const_iterator pi;
+
+    si = strs.begin();
+    while(si != strs.end())
+      {
+        int match = FNM_NOMATCH;
+
+        for(pi = patterns.begin();
+            pi != patterns.end() && match != 0;
+            ++pi)
+          {
+            match = fnmatch(pi->c_str(),si->c_str(),0);
+          }
+
+        if(match == 0)
+          si = strs.erase(si);
+        else
+          ++si;
+      }
+  }
+
   namespace find
   {
     void

src/fs.hpp

@@ -104,6 +104,12 @@ namespace fs
   int copyattr(const string from,
                const string to);
 
+  void glob(const vector<string> &patterns,
+            vector<string>       &strs);
+
+  void erase_fnmatches(const vector<string> &patterns,
+                       vector<string>       &strs);
+
   namespace find
   {
     void invalid(const vector<string> &basepaths,

src/getattr.cpp

@@ -35,7 +35,7 @@
 #include "config.hpp"
 #include "fs.hpp"
 #include "ugid.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -90,13 +90,15 @@ namespace mergerfs
     getattr(const char  *fusepath,
             struct stat *st)
     {
-      const struct fuse_context *fc     = fuse_get_context();
-      const config::Config      &config = config::get();
-      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const config::Config &config = config::get();
 
       if(fusepath == config.controlfile)
         return _getattr_controlfile(*st);
 
+      const struct fuse_context *fc = fuse_get_context();
+      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
+
       return _getattr(*config.search,
                       config.srcmounts,
                       fusepath,

src/getxattr.cpp

@@ -34,8 +34,9 @@
 #include "config.hpp"
 #include "fs.hpp"
 #include "ugid.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 #include "xattr.hpp"
+#include "str.hpp"
 
 using std::string;
 using std::vector;
@@ -57,6 +58,8 @@ _getxattr_controlfile(const Config &config,
     attrvalue = (std::string)*config.create;
   else if(attrname == "user.mergerfs.search")
     attrvalue = (std::string)*config.search;
+  else if(attrname == "user.mergerfs.srcmounts")
+    attrvalue = str::join(config.srcmounts,':');
 
   if(attrvalue.empty())
     return -ENOATTR;
@@ -133,9 +136,7 @@ namespace mergerfs
              char       *buf,
              size_t      count)
     {
-      const struct fuse_context *fc     = fuse_get_context();
-      const config::Config      &config = config::get();
-      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const config::Config &config = config::get();
 
       if(fusepath == config.controlfile)
         return _getxattr_controlfile(config,
@@ -143,6 +144,10 @@ namespace mergerfs
                                      buf,
                                      count);
 
+      const struct fuse_context *fc = fuse_get_context();
+      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
+
       return _getxattr(*config.search,
                        config.srcmounts,
                        fusepath,

src/link.cpp

@@ -33,7 +33,7 @@
 #include "config.hpp"
 #include "fs.hpp"
 #include "ugid.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -97,6 +97,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _link(*config.action,
                    config.srcmounts,

src/listxattr.cpp

@@ -35,7 +35,7 @@
 #include "category.hpp"
 #include "fs.hpp"
 #include "ugid.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 #include "xattr.hpp"
 
 using std::string;
@@ -47,23 +47,22 @@ int
 _listxattr_controlfile(char         *list,
                        const size_t  size)
 {
-  size_t xattrssize;
-  string xattrs;
-
-  for(int i = Category::Enum::BEGIN; i < Category::Enum::END; ++i)
-    xattrs += "user.mergerfs." + (string)Category::categories[i] + '\0';
-
-  xattrssize = xattrs.size();
+  const char xattrs[] =
+    "user.mergerfs.srcmounts\0"
+    "user.mergerfs.action\0"
+    "user.mergerfs.create\0"
+    "user.mergerfs.search"
+    ;
 
   if(size == 0)
-    return xattrssize;
+    return sizeof(xattrs);
 
-  if(size < xattrssize)
+  if(size < sizeof(xattrs))
     return -ERANGE;
 
-  memcpy(list,xattrs.data(),xattrssize);
+  memcpy(list,xattrs,sizeof(xattrs));
 
-  return xattrssize;
+  return sizeof(xattrs);
 }
 
 static
@@ -99,14 +98,16 @@ namespace mergerfs
               char       *list,
               size_t      size)
     {
-      const struct fuse_context *fc = fuse_get_context();
-      const config::Config      &config = config::get();
-      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const config::Config &config = config::get();
 
       if(fusepath == config.controlfile)
         return _listxattr_controlfile(list,
                                       size);
 
+      const struct fuse_context *fc = fuse_get_context();
+      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
+
       return _listxattr(*config.search,
                         config.srcmounts,
                         fusepath,

src/mkdir.cpp

@@ -35,7 +35,7 @@
 #include "fileinfo.hpp"
 #include "fs.hpp"
 #include "config.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -84,6 +84,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _mkdir(*config.search,
                     *config.create,

src/mknod.cpp

@@ -36,7 +36,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -87,6 +87,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _mknod(*config.search,
                     *config.create,

src/open.cpp

@@ -35,7 +35,7 @@
 #include "fileinfo.hpp"
 #include "fs.hpp"
 #include "config.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -75,7 +75,8 @@ namespace mergerfs
     {
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
-      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);;
+      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _open(*config.search,
                    config.srcmounts,

src/option_parser.cpp

@@ -27,13 +27,13 @@
 #include <stddef.h>
 #include <string.h>
 #include <stdio.h>
-#include <glob.h>
 
 #include <string>
 #include <vector>
 #include <sstream>
 #include <iostream>
 
+#include "str.hpp"
 #include "config.hpp"
 #include "policy.hpp"
 
@@ -41,25 +41,6 @@ using std::string;
 using std::vector;
 using namespace mergerfs;
 
-template<typename Container>
-Container&
-split(Container                                  &result,
-      const typename Container::value_type       &s,
-      typename Container::value_type::value_type  delimiter)
-{
-  std::istringstream ss(s);
-  while(!ss.eof())
-    {
-      typename Container::value_type field;
-      std::getline(ss,field,delimiter);
-      if(field.empty())
-        continue;
-      result.push_back(field);
-    }
-
-  return result;
-}
-
 static
 int
 process_opt(config::Config    &config,
@@ -68,7 +49,7 @@ process_opt(config::Config    &config,
   int rv = 0;
   std::vector<std::string> argvalue;
 
-  split(argvalue,arg,'=');
+  str::split(argvalue,arg,'=');
   switch(argvalue.size())
     {
     case 2:
@@ -91,26 +72,27 @@ process_opt(config::Config    &config,
 }
 
 static
-void
+int
 process_srcmounts(const char     *arg,
                   config::Config &config)
 {
-  int flags;
-  glob_t gbuf;
   vector<string> paths;
 
-  flags = 0;
-  split(paths,arg,':');
-  for(size_t i = 0; i < paths.size(); i++)
-    {
-      glob(paths[i].c_str(),flags,NULL,&gbuf);
-      flags = GLOB_APPEND;
-    }
+  str::split(paths,arg,':');
+
+  fs::glob(paths,config.srcmounts);
+
+  return 0;
+}
 
-  for(size_t i = 0; i < gbuf.gl_pathc; ++i)
-    config.srcmounts.push_back(gbuf.gl_pathv[i]);
+static
+int
+process_destmounts(const char     *arg,
+                   config::Config &config)
+{
+  config.destmount = arg;
 
-  globfree(&gbuf);
+  return 1;
 }
 
 static
@@ -130,10 +112,9 @@ option_processor(void             *data,
       break;
 
     case FUSE_OPT_KEY_NONOPT:
-      if(config.srcmounts.empty())
-        process_srcmounts(arg,config);
-      else
-        rv = (config.destmount = arg,1);
+      rv = config.srcmounts.empty() ?
+        process_srcmounts(arg,config) :
+        process_destmounts(arg,config);
       break;
 
     default:
@@ -152,10 +133,7 @@ set_fsname(struct fuse_args     &args,
     {
       std::string fsname;
 
-      fsname  = "-ofsname=";
-      fsname += config.srcmounts[0];
-      for(size_t i = 1; i < config.srcmounts.size(); i++)
-        fsname += ';' + config.srcmounts[i];
+      fsname = "-ofsname=" + str::join(config.srcmounts,':');
 
       fuse_opt_insert_arg(&args,1,fsname.c_str());
     }

src/read.cpp

@@ -29,7 +29,6 @@
 #include <string.h>
 
 #include <string>
-#include <algorithm>
 
 #include "fileinfo.hpp"
 

src/readdir.cpp

@@ -35,6 +35,7 @@
 #include "config.hpp"
 #include "ugid.hpp"
 #include "fs.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -125,6 +126,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _readdir(config.srcmounts,
                       fusepath,

src/readlink.cpp

@@ -33,7 +33,7 @@
 #include "config.hpp"
 #include "ugid.hpp"
 #include "fs.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -75,6 +75,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _readlink(*config.search,
                        config.srcmounts,

src/release.cpp

@@ -54,9 +54,9 @@ namespace mergerfs
   {
     int
     release(const char            *fusepath,
-            struct fuse_file_info *fi)
+            struct fuse_file_info *ffi)
     {
-      return _release(fi->fh);
+      return _release(ffi->fh);
     }
   }
 }

src/removexattr.cpp

@@ -33,7 +33,7 @@
 #include "config.hpp"
 #include "ugid.hpp"
 #include "fs.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 #include "xattr.hpp"
 
 using std::string;
@@ -79,13 +79,15 @@ namespace mergerfs
     removexattr(const char *fusepath,
                 const char *attrname)
     {
-      const struct fuse_context *fc     = fuse_get_context();
-      const config::Config      &config = config::get();
-      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const config::Config &config = config::get();
 
       if(fusepath == config.controlfile)
         return -ENOTSUP;
 
+      const struct fuse_context *fc = fuse_get_context();
+      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
+
       return _removexattr(*config.action,
                           config.srcmounts,
                           fusepath,

src/rename.cpp

@@ -34,6 +34,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -73,6 +74,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _rename(*config.search,
                      config.srcmounts,

src/rmdir.cpp

@@ -32,6 +32,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -74,6 +75,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readguard(&config.srcmountslock);
 
       return _rmdir(*config.action,
                     config.srcmounts,

src/rwlock.hpp

@@ -0,0 +1,71 @@
+/*
+   The MIT License (MIT)
+
+   Copyright (c) 2014 Antonio SJ Musumeci <trapexit@spawn.link>
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+#include <pthread.h>
+
+namespace mergerfs
+{
+  namespace rwlock
+  {
+    class ReadGuard
+    {
+    public:
+      ReadGuard(pthread_rwlock_t *lock)
+      {
+        _lock = lock;
+        pthread_rwlock_rdlock(_lock);
+      }
+
+      ~ReadGuard()
+      {
+        pthread_rwlock_unlock(_lock);
+      }
+
+      pthread_rwlock_t *_lock;
+
+    private:
+      ReadGuard();
+    };
+
+    class WriteGuard
+    {
+    public:
+      WriteGuard(pthread_rwlock_t *lock)
+      {
+        _lock = lock;
+        pthread_rwlock_wrlock(_lock);
+      }
+
+      ~WriteGuard()
+      {
+        pthread_rwlock_unlock(_lock);
+      }
+
+      pthread_rwlock_t *_lock;
+
+    private:
+      WriteGuard();
+    };
+  }
+}

src/setxattr.cpp

@@ -34,8 +34,9 @@
 #include "config.hpp"
 #include "fs.hpp"
 #include "ugid.hpp"
-#include "assert.hpp"
+#include "rwlock.hpp"
 #include "xattr.hpp"
+#include "str.hpp"
 
 using std::string;
 using std::vector;
@@ -43,45 +44,135 @@ using mergerfs::Policy;
 using mergerfs::Category;
 using namespace mergerfs;
 
-template<typename Container>
-Container&
-split(Container                                  &result,
-      const typename Container::value_type       &s,
-      typename Container::value_type::value_type  delimiter)
+static
+int
+_add_srcmounts(vector<string>           &srcmounts,
+               pthread_rwlock_t         &srcmountslock,
+               const string              destmount,
+               const string              values,
+               vector<string>::iterator  pos)
 {
-  std::string        str;
-  std::istringstream ss(s);
+  vector<string> patterns;
+  vector<string> additions;
 
-  while(std::getline(ss,str,delimiter))
-    result.push_back(str);
+  str::split(patterns,values,':');
+  fs::glob(patterns,additions);
 
-  return result;
+  if(!additions.empty())
+    {
+      const rwlock::WriteGuard wrg(&srcmountslock);
+
+      srcmounts.insert(pos,
+                       additions.begin(),
+                       additions.end());
+    }
+
+  return 0;
 }
 
 static
 int
-_setxattr_controlfile(config::Config &config,
-                      const string    attrname,
-                      const string    attrval,
-                      const size_t    attrvalsize,
-                      const int       flags)
+_erase_srcmounts(vector<string>   &srcmounts,
+                 pthread_rwlock_t  srcmountslock,
+                 const string     &values)
 {
-  const Category *cat;
-  const Policy   *policy;
-  vector<string>  nameparts;
+  if(srcmounts.empty())
+    return 0;
 
-  split(nameparts,attrname,'.');
+  vector<string> patterns;
 
-  if(nameparts.size() != 3)
-    return -EINVAL;
+  str::split(patterns,values,':');
 
-  if(nameparts[0] != "user")
-    return -ENOATTR;
+  const rwlock::WriteGuard wrg(&srcmountslock);
 
-  if(nameparts[1] != "mergerfs")
-    return -ENOATTR;
+  fs::erase_fnmatches(patterns,srcmounts);
+
+  return 0;
+}
+
+static
+int
+_replace_srcmounts(vector<string>   &srcmounts,
+                   pthread_rwlock_t  srcmountslock,
+                   const string      destmount,
+                   const string      values)
+{
+  vector<string> patterns;
+  vector<string> newmounts;
+
+  str::split(patterns,values,':');
+  fs::glob(patterns,newmounts);
+
+  {
+    const rwlock::WriteGuard wrg(&srcmountslock);
+
+    srcmounts.swap(newmounts);
+  }
+
+  return 0;
+}
+
+static
+void
+_split_attrval(const string  attrval,
+               string       &instruction,
+               string       &values)
+{
+  size_t offset;
+
+  offset = attrval.find_first_of('/');
+  instruction = attrval.substr(0,offset);
+  if(offset != string::npos)
+    values = attrval.substr(offset);
+}
+
+static
+int
+_setxattr_srcmounts(vector<string>   &srcmounts,
+                    pthread_rwlock_t &srcmountslock,
+                    const string      destmount,
+                    const string      attrval,
+                    const int         flags)
+{
+  string instruction;
+  string values;
+
+  if((flags & XATTR_CREATE) == XATTR_CREATE)
+    return -EEXIST;
+
+  _split_attrval(attrval,instruction,values);
+
+  if(instruction == "+")
+    return _add_srcmounts(srcmounts,srcmountslock,destmount,values,srcmounts.end());
+  else if(instruction == "+<")
+    return _add_srcmounts(srcmounts,srcmountslock,destmount,values,srcmounts.begin());
+  else if(instruction == "+>")
+    return _add_srcmounts(srcmounts,srcmountslock,destmount,values,srcmounts.end());
+  else if(instruction == "-")
+    return _erase_srcmounts(srcmounts,srcmountslock,values);
+  else if(instruction == "-<")
+    return _erase_srcmounts(srcmounts,srcmountslock,srcmounts.front());
+  else if(instruction == "->")
+    return _erase_srcmounts(srcmounts,srcmountslock,srcmounts.back());
+  else if(instruction == "=")
+    return _replace_srcmounts(srcmounts,srcmountslock,destmount,values);
+  else if(instruction.empty())
+    return _replace_srcmounts(srcmounts,srcmountslock,destmount,values);
+
+  return -EINVAL;
+}
+
+static
+int
+_setxattr_policy(const Policy *policies[],
+                 const string  attrname,
+                 const string  attrval,
+                 const int     flags)
+{
+  const Category *cat;
+  const Policy   *policy;
 
-  cat = Category::find(nameparts[2]);
+  cat = Category::find(attrname);
   if(cat == Category::invalid)
     return -ENOATTR;
 
@@ -92,11 +183,43 @@ _setxattr_controlfile(config::Config &config,
   if(policy == Policy::invalid)
     return -EINVAL;
 
-  config.policies[*cat] = policy;
+  policies[*cat] = policy;
 
   return 0;
 }
 
+static
+int
+_setxattr_controlfile(config::Config &config,
+                      const string    attrname,
+                      const string    attrval,
+                      const int       flags)
+{
+  vector<string>  nameparts;
+
+  str::split(nameparts,attrname,'.');
+
+  if(nameparts.size() != 3      ||
+     nameparts[0]     != "user" ||
+     nameparts[1]     != "mergerfs")
+    return -ENOATTR;
+
+  if(attrval.empty())
+    return -EINVAL;
+
+  if(nameparts[2] == "srcmounts")
+    return _setxattr_srcmounts(config.srcmounts,
+                               config.srcmountslock,
+                               config.destmount,
+                               attrval,
+                               flags);
+
+  return _setxattr_policy(config.policies,
+                          nameparts[2],
+                          attrval,
+                          flags);
+}
+
 static
 int
 _setxattr(const fs::SearchFunc  searchFunc,
@@ -142,24 +265,27 @@ namespace mergerfs
              size_t      attrvalsize,
              int         flags)
     {
-      const struct fuse_context *fc     = fuse_get_context();
-      const config::Config      &config = config::get();
-      const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const config::Config &config = config::get();
 
       if(fusepath == config.controlfile)
         return _setxattr_controlfile(config::get_writable(),
                                      attrname,
                                      string(attrval,attrvalsize),
-                                     attrvalsize,
                                      flags);
 
-      return _setxattr(*config.action,
-                       config.srcmounts,
-                       fusepath,
-                       attrname,
-                       attrval,
-                       attrvalsize,
-                       flags);
+      {
+        const struct fuse_context *fc = fuse_get_context();
+        const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+        const rwlock::ReadGuard    readlock(&config.srcmountslock);
+
+        return _setxattr(*config.action,
+                         config.srcmounts,
+                         fusepath,
+                         attrname,
+                         attrval,
+                         attrvalsize,
+                         flags);
+      }
     }
   }
 }

src/statfs.cpp

@@ -34,6 +34,7 @@
 
 #include "ugid.hpp"
 #include "config.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -126,6 +127,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _statfs(config.srcmounts,
                      *stat);

src/str.cpp

@@ -0,0 +1,60 @@
+/*
+   The MIT License (MIT)
+
+   Copyright (c) 2014 Antonio SJ Musumeci <trapexit@spawn.link>
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+#include <string>
+#include <vector>
+#include <sstream>
+
+using std::string;
+using std::vector;
+using std::istringstream;
+
+namespace str
+{
+  void
+  split(vector<string> &result,
+        const string    str,
+        const char      delimiter)
+  {
+    string part;
+    istringstream ss(str);
+
+    while(std::getline(ss,part,delimiter))
+      result.push_back(part);
+  }
+
+  string
+  join(const vector<string> &vec,
+       const char            sep)
+  {
+    if(vec.empty())
+      return string();
+
+    string rv = vec[0];
+    for(size_t i = 1; i < vec.size(); i++)
+      rv += sep + vec[i];
+
+    return rv;
+  }
+}

src/str.hpp

@@ -0,0 +1,36 @@
+/*
+   The MIT License (MIT)
+
+   Copyright (c) 2014 Antonio SJ Musumeci <trapexit@spawn.link>
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+#include <string>
+#include <vector>
+
+namespace str
+{
+  void split(std::vector<std::string> &result,
+             const std::string         str,
+             const char                delimiter);
+
+  std::string join(const std::vector<std::string> &vec,
+                   const char                      sep);
+}

src/symlink.cpp

@@ -32,6 +32,7 @@
 #include "fs.hpp"
 #include "config.hpp"
 #include "ugid.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -67,6 +68,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _symlink(config.srcmounts,
                       oldpath,

src/truncate.cpp

@@ -34,6 +34,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -77,6 +78,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _truncate(*config.action,
                        config.srcmounts,

src/unlink.cpp

@@ -33,6 +33,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -74,6 +75,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _unlink(*config.action,
                      config.srcmounts,

src/utimens.cpp

@@ -34,6 +34,7 @@
 #include "ugid.hpp"
 #include "fs.hpp"
 #include "config.hpp"
+#include "rwlock.hpp"
 
 using std::string;
 using std::vector;
@@ -77,6 +78,7 @@ namespace mergerfs
       const struct fuse_context *fc     = fuse_get_context();
       const config::Config      &config = config::get();
       const ugid::SetResetGuard  ugid(fc->uid,fc->gid);
+      const rwlock::ReadGuard    readlock(&config.srcmountslock);
 
       return _utimens(*config.action,
                       config.srcmounts,

src/write.cpp

@@ -52,9 +52,9 @@ namespace mergerfs
           const char            *buf,
           size_t                 count,
           off_t                  offset,
-          struct fuse_file_info *fi)
+          struct fuse_file_info *ffi)
     {
-      return _write(((FileInfo*)fi->fh)->fd,
+      return _write(((FileInfo*)ffi->fh)->fd,
                     buf,
                     count,
                     offset);