add virtual filesystem support (remapping file paths)

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

config.go

@@ -13,15 +13,15 @@ import (
  */
 type ServerConfig struct {
     /* Executable Settings */
-    Env               []string
-    CgiEnv            []string
-    CgiEnabled        bool
-    MaxExecRunTime    time.Duration
+    Env                []string
+    CgiEnv             []string
+    CgiEnabled         bool
+    MaxExecRunTime     time.Duration
 
     /* Content settings */
-    CharSet           string
-    FooterText        []byte
-    PageWidth         int
+    CharSet            string
+    FooterText         []byte
+    PageWidth          int
 
     /* Regex */
     CmdParseLineRegex  *regexp.Regexp
@@ -29,13 +29,13 @@ type ServerConfig struct {
     RestrictedCommands []*regexp.Regexp
 
     /* Logging */
-    SysLog            LoggerInterface
-    AccLog            LoggerInterface
+    SysLog             LoggerInterface
+    AccLog             LoggerInterface
 
     /* Filesystem access */
-    FileSystem        *FileSystem
+    FileSystem         *FileSystem
 
-    /*  */
+    /* Buffer sizes */
     SocketWriteBufSize int
     SocketReadBufSize  int
     SocketReadMax      int

filesystem.go

@@ -24,20 +24,40 @@ type FileSystem struct {
     CacheMap     *FixedMap    /* Fixed size cache map */
     CacheMutex   sync.RWMutex /* RWMutex for safe cachemap access */
     CacheFileMax int64        /* Cache file size max */
+    Remap        map[string]string
+    ReverseRemap map[string]string
 }
 
 func (fs *FileSystem) Init(size int, fileSizeMax float64) {
     fs.CacheMap     = NewFixedMap(size)
     fs.CacheMutex   = sync.RWMutex{}
     fs.CacheFileMax = int64(BytesInMegaByte * fileSizeMax)
+    /* {,Reverse}Remap map is setup in `gophor.go`, no need to here */
+}
+
+func (fs *FileSystem) RemapRequestPath(requestPath *RequestPath) {
+    realPath, ok := fs.Remap[requestPath.Relative()]
+    if ok {
+        requestPath.RemapActual(realPath)
+    }
+}
+
+func (fs *FileSystem)ReverseRemapRequestPath(requestPath *RequestPath) {
+    virtualPath, ok := fs.Remap[requestPath.Relative()]
+    if ok {
+        requestPath.RemapVirtual(virtualPath)
+    }
 }
 
 func (fs *FileSystem) HandleRequest(responder *Responder) *GophorError {
     /* Check if restricted file */
-    if isRestrictedFile(responder.Request.AbsPath()) {
+    if isRestrictedFile(responder.Request.RelPath()) {
         return &GophorError{ IllegalPathErr, nil }
     }
 
+    /* Remap RequestPath if necessary */
+    fs.RemapRequestPath(responder.Request.Path)
+
     /* Get filesystem stat, check it exists! */
     stat, err := os.Stat(responder.Request.AbsPath())
     if err != nil {

filesystem_read.go

@@ -140,24 +140,29 @@ func listDir(responder *Responder, hidden map[string]bool) *GophorError {
     dirContents = append(dirContents, buildLine(TypeDirectory, "..", responder.Request.PathJoinSelector(".."), responder.Host.Name(), responder.Host.Port())...)
 
     /* Walk through files :D */
+    var reqPath *RequestPath
     for _, file := range files {
-        /* If regex match in restricted files || requested hidden */
-        if _, ok := hidden[file.Name()]; ok {
+        reqPath = NewRequestPath(responder.Request.RootDir(), file.Name())
+
+        /* If hidden file, or restricted file, continue! */
+        if isHiddenFile(hidden, file.Name()) || isRestrictedFile(reqPath.Relative()) {
             continue
         }
 
+        /* If requires remap, do so! */
+        Config.FileSystem.ReverseRemapRequestPath(reqPath)
+
         /* Handle file, directory or ignore others */
         switch {
             case file.Mode() & os.ModeDir != 0:
                 /* Directory -- create directory listing */
-                itemPath := responder.Request.PathJoinSelector(file.Name())
-                dirContents = append(dirContents, buildLine(TypeDirectory, file.Name(), itemPath, responder.Host.Name(), responder.Host.Port())...)
+                dirContents = append(dirContents, buildLine(TypeDirectory, file.Name(), reqPath.Selector(), responder.Host.Name(), responder.Host.Port())...)
 
             case file.Mode() & os.ModeType == 0:
                 /* Regular file -- find item type and creating listing */
-                itemPath := responder.Request.PathJoinSelector(file.Name())
+                itemPath := reqPath.Selector()
                 itemType := getItemType(itemPath)
-                dirContents = append(dirContents, buildLine(itemType, file.Name(), itemPath, responder.Host.Name(), responder.Host.Port())...)
+                dirContents = append(dirContents, buildLine(itemType, file.Name(), reqPath.Selector(), responder.Host.Name(), responder.Host.Port())...)
 
             default:
                 /* Ignore */
@@ -168,6 +173,11 @@ func listDir(responder *Responder, hidden map[string]bool) *GophorError {
     return responder.WriteFlush(append(dirContents, Config.FooterText...))
 }
 
+func isHiddenFile(hiddenMap map[string]bool, fileName string) bool {
+    _, ok := hiddenMap[fileName]
+    return ok
+}
+
 /* Took a leaf out of go-gopher's book here. */
 type byName []os.FileInfo
 func (s byName) Len() int           { return len(s) }

format.go

@@ -174,21 +174,21 @@ func buildLine(t ItemType, name, selector, host string, port string) []byte {
 
     /* Add name, truncate name if too long */    
     if len(name) > Config.PageWidth {
-        ret += name[:Config.PageWidth-5]+"...\t"
+        ret += name[:Config.PageWidth-5]+"..."+Tab
     } else {
-        ret += name+"\t"
+        ret += name+Tab
     }
 
     /* Add selector. If too long use err, skip if empty */
     selectorLen := len(selector)
     if selectorLen > MaxSelectorLen {
-        ret += SelectorErrorStr+"\t"
+        ret += SelectorErrorStr+Tab
     } else if selectorLen > 0 {
-        ret += selector+"\t"
+        ret += selector+Tab
     }
 
     /* Add host + port */
-    ret += host+"\t"+port+DOSLineEnd
+    ret += host+Tab+port+DOSLineEnd
 
     return []byte(ret)
 }

gophor.go

@@ -2,6 +2,7 @@ package main
 
 import (
     "os"
+    "log"
     "strconv"
     "syscall"
     "os/signal"
@@ -69,8 +70,11 @@ func setupServer() []*GophorListener {
     logOutput          := flag.String("log-output", "stderr", "Change server log file handling (disable|stderr|file)")
     logOpts            := flag.String("log-opts", "timestamp,ip", "Comma-separated list of log options (timestamp|ip)")
 
-    /* Cache settings */
+    /* File system */
     fileMonitorFreq    := flag.Duration("file-monitor-freq", time.Second*60, "Change file monitor frequency.")
+    fileSystemRemap    := flag.String("file-remap", "", "New-line separated list of file remappings of format: `/virtual/relative/path -> /actual/relative/path`")
+
+    /* Cache settings */
     cacheSize          := flag.Int("cache-size", 50, "Change file cache size, measured in file count.")
     cacheFileSizeMax   := flag.Float64("cache-file-max", 0.5, "Change maximum file size to be cached (in megabytes).")
     cacheDisabled      := flag.Bool("disable-cache", false, "Disable file caching.")
@@ -134,8 +138,6 @@ func setupServer() []*GophorListener {
     if *disableCgi {
         Config.SysLog.Info("", "CGI support disabled")
         Config.CgiEnabled = false
-
-
     } else {
         /* Enable CGI */
         Config.SysLog.Info("", "CGI support enabled")
@@ -157,7 +159,7 @@ func setupServer() []*GophorListener {
 
     /* If running as root, get ready to drop privileges */
     if syscall.Getuid() == 0 || syscall.Getgid() == 0 {
-        Config.SysLog.Fatal("", "Gophor does not support running as root!\n")
+        log.Fatalf("", "Gophor does not support running as root!\n")
     }
 
     /* Enter server dir */
@@ -176,11 +178,11 @@ func setupServer() []*GophorListener {
 
         l, err := BeginGophorListen(*serverBindAddr, *serverHostname, strconv.Itoa(*serverPort), strconv.Itoa(*serverFwdPort), *serverRoot)
         if err != nil {
-            Config.SysLog.Fatal("", "Error setting up (unencrypted) listener: %s\n", err.Error())
+            log.Fatalf("Error setting up (unencrypted) listener: %s\n", err.Error())
         }
         listeners = append(listeners, l)
     } else {
-        Config.SysLog.Fatal("", "No valid port to listen on\n")
+        log.Fatalf("No valid port to listen on\n")
     }
 
     /* Compile regex statements */
@@ -213,6 +215,9 @@ func setupServer() []*GophorListener {
         cachePolicyFiles(*serverRoot, *serverDescription, *serverAdmin, *serverGeoloc)
     }
 
+    /* Setup file remappings */
+    Config.FileSystem.Remap, Config.FileSystem.ReverseRemap = parseFileSystemRemaps(*fileSystemRemap)
+
     /* Return the created listeners slice :) */
     return listeners
 }
@@ -220,6 +225,6 @@ func setupServer() []*GophorListener {
 func enterServerDir(path string) {
     err := syscall.Chdir(path)
     if err != nil {
-        Config.SysLog.Fatal("", "Error changing dir to server root %s: %s\n", path, err.Error())
+        log.Fatalf("Error changing dir to server root %s: %s\n", path, err.Error())
     }
 }

logger.go

@@ -52,11 +52,11 @@ func (l *Logger) Fatal(prefix, format string, args ...interface{}) {
     l.Logger.Fatalf(LogPrefixFatal+prefix+format, args...)
 }
 
+/* Logger implementation that ignores the prefix (e.g. when not printing IPs) */
 type LoggerNoPrefix struct {
     Logger *log.Logger
 }
 
-/* Logger implementation that ignores the prefix (e.g. when not printing IPs) */
 func (l *LoggerNoPrefix) Info(prefix, format string, args ...interface{}) {
     /* Ignore the prefix */
     l.Logger.Printf(LogPrefixInfo+format, args...)

parse.go

@@ -2,8 +2,40 @@ package main
 
 import (
     "strings"
+    "log"
 )
 
+const (
+    FileRemapSeparator = " -> "
+)
+
+/* Parse file system remaps */
+func parseFileSystemRemaps(fileSystemRemap string) (map[string]string, map[string]string) {
+    remap := make(map[string]string)
+    reverseRemap := make(map[string]string)
+
+    for _, remapEntry := range strings.Split(fileSystemRemap, UnixLineEnd) {
+        /* Empty remap entry */
+        if len(remapEntry) == 0 {
+            continue
+        }
+
+        /* Split remap entry into virtual and actual path, then append */
+        mapSplit := strings.Split(remapEntry, FileRemapSeparator)
+        if len(mapSplit) != 2 {
+            log.Fatalf("Invalid filesystem remap entry: %s\n", remapEntry)
+        } else {
+            virtualPath := strings.TrimPrefix(mapSplit[0], "/")
+            actualPath := strings.TrimPrefix(mapSplit[1], "/")
+
+            remap[virtualPath] = actualPath
+            reverseRemap[actualPath] = virtualPath
+        }
+    }
+
+    return remap, reverseRemap
+}
+
 /* Parse a request string into a path and parameters string */
 func parseRequestString(request string) (string, []string) {
     /* Read up to first '?' and then put rest into single slice string array */

request.go

@@ -12,13 +12,23 @@ type RequestPath struct {
      * and filesystem reading
      */
 
-    Root string
-    Rel  string
-    Abs  string
+    Root   string
+    Rel    string
+    Abs    string
+    Select string
 }
 
 func NewRequestPath(rootDir, relPath string) *RequestPath {
-    return &RequestPath{ rootDir, relPath, path.Join(rootDir, strings.TrimSuffix(relPath, "/")) }
+    return &RequestPath{ rootDir, relPath, path.Join(rootDir, strings.TrimSuffix(relPath, "/")), relPath }
+}
+
+func (rp *RequestPath) RemapActual(newRel string) {
+    rp.Rel = newRel
+    rp.Abs = path.Join(rp.Root, strings.TrimSuffix(newRel, "/"))
+}
+
+func (rp *RequestPath) RemapVirtual(newSel string) {
+    rp.Select = newSel
 }
 
 func (rp *RequestPath) RootDir() string {
@@ -34,10 +44,10 @@ func (rp *RequestPath) Absolute() string {
 }
 
 func (rp *RequestPath) Selector() string {
-    if rp.Rel == "." {
+    if rp.Select == "." {
         return "/"
     } else {
-        return "/"+rp.Rel
+        return "/"+rp.Select
     }
 }