Fix requirement for PATH_MAX

POSIX says PATH_MAX *may* be defined and on GNU Hurd it is in fact not
defined. This commit uses dynamic allocation to avoid relying on
PATH_MAX being defined.

Author: Thomas Preud'homme <robotux@debian.org>
Forwarded: https://github.com/alphaonex86/Ultracopier/pull/51
Applied-Upstream: commit:02afb78e2345f5c6fd0891fad554dca13179a0cd
Last-Update: 2020-08-31

3 files changed, 35 insertions, 20 deletions

diff --git a/plugins/CopyEngine/Ultracopier-Spec/ScanFileOrFolder.cpp b/plugins/CopyEngine/Ultracopier-Spec/ScanFileOrFolder.cpp
index 014585d..940dddb 100755
--- a/plugins/CopyEngine/Ultracopier-Spec/ScanFileOrFolder.cpp
+++ b/plugins/CopyEngine/Ultracopier-Spec/ScanFileOrFolder.cpp
@@ -331,9 +331,14 @@ void ScanFileOrFolder::run()
 INTERNALTYPEPATH ScanFileOrFolder::resolvDestination(const INTERNALTYPEPATH &destination)
 {
     INTERNALTYPEPATH temp(destination);
-    char buf[PATH_MAX];
+    std::vector<char> buf(512);
     ssize_t nbytes=0;
-    nbytes=readlink(TransferThread::internalStringTostring(destination).c_str(), buf, sizeof(buf));
+    do {
+      buf.resize(buf.size()*2);
+      nbytes=readlink(TransferThread::internalStringTostring(destination).c_str(), buf.data(), buf.size());
+    } while (nbytes == buf.size());
+    if (nbytes!=-1)
+      buf.resize(nbytes);
     while(nbytes!=-1) {
         temp=FSabsolutePath(temp);
         if(!stringEndsWith(destination,'/')
@@ -342,14 +347,19 @@ INTERNALTYPEPATH ScanFileOrFolder::resolvDestination(const INTERNALTYPEPATH &des
             #endif
                 )
             temp+=TransferThread::stringToInternalString("/");
-        temp+=TransferThread::stringToInternalString(std::string(buf,nbytes));
+        temp+=TransferThread::stringToInternalString(std::string(buf.data(), buf.size()));
         /// \todo change for pure c++ code
         #ifdef WIDESTRING
         temp=QFileInfo(QString::fromStdWString(temp)).absoluteFilePath().toStdWString();
         #else
         temp=QFileInfo(QString::fromStdString(temp)).absoluteFilePath().toStdString();
         #endif
-        nbytes=readlink(TransferThread::internalStringTostring(temp).c_str(), buf, sizeof(buf));
+        do {
+          buf.resize(buf.size() * 2);
+          nbytes=readlink(TransferThread::internalStringTostring(temp).c_str(), buf.data(), buf.size());
+        } while (nbytes == buf.size());
+        if (nbytes!=-1)
+          buf.resize(nbytes);
     }
     return temp;
     /*do
diff --git a/plugins/CopyEngine/Ultracopier-Spec/TransferThread.cpp b/plugins/CopyEngine/Ultracopier-Spec/TransferThread.cpp
index 9cbad5a..d986b49 100755
--- a/plugins/CopyEngine/Ultracopier-Spec/TransferThread.cpp
+++ b/plugins/CopyEngine/Ultracopier-Spec/TransferThread.cpp
@@ -737,8 +737,7 @@ bool TransferThread::mkpath(const INTERNALTYPEPATH &path)
     } while(!pathSplit.empty());
     return true;
     #else
-    char pathC[PATH_MAX];
-    strcpy(pathC,TransferThread::internalStringTostring(path).c_str());
+    std::string pathC(TransferThread::internalStringTostring(path));
     if(!mkdir(path))
         if(errno==EEXIST)
             return true;
@@ -748,8 +747,7 @@ bool TransferThread::mkpath(const INTERNALTYPEPATH &path)
     std::string::size_type previouspos=path.size();
     std::string::size_type lastpos=std::string::npos;
 
-    char pathCedit[PATH_MAX];
-    strcpy(pathCedit,pathC);
+    std::string pathCedit(pathC);
     std::vector<std::string::size_type> pathSplit;
     pathSplit.push_back(path.size());
     do
@@ -773,14 +771,14 @@ bool TransferThread::mkpath(const INTERNALTYPEPATH &path)
             return false;
         #endif
 
-        pathCedit[lastpos]='\0';
+	pathCedit.resize(lastpos);
         previouspos=lastpos;
 
         errno=0;
         #ifdef Q_OS_UNIX
-        if(::mkdir(pathCedit, mode)==-1)
+        if(::mkdir(pathCedit.c_str(), mode)==-1)
         #else
-        if(::mkdir(pathCedit)==-1)
+        if(::mkdir(pathCedit.c_str())==-1)
         #endif
             if(errno!=EEXIST && errno!=ENOENT)
                 return false;
@@ -791,14 +789,14 @@ bool TransferThread::mkpath(const INTERNALTYPEPATH &path)
 
     do
     {
-        strcpy(pathCedit,pathC);
+        pathCedit = pathC;
         lastpos=pathSplit.back();
         pathSplit.pop_back();
-        pathCedit[lastpos]='\0';
+        pathCedit.resize(lastpos);
         #ifdef Q_OS_UNIX
-        if(::mkdir(pathCedit, mode)==-1)
+        if(::mkdir(pathCedit.c_str(), mode)==-1)
         #else
-        if(::mkdir(pathCedit)==-1)
+        if(::mkdir(pathCedit.c_str())==-1)
         #endif
             if(errno!=EEXIST)
                 return false;
diff --git a/plugins/CopyEngine/Ultracopier-Spec/async/TransferThreadAsync.cpp b/plugins/CopyEngine/Ultracopier-Spec/async/TransferThreadAsync.cpp
index b5af928..b291b21 100755
--- a/plugins/CopyEngine/Ultracopier-Spec/async/TransferThreadAsync.cpp
+++ b/plugins/CopyEngine/Ultracopier-Spec/async/TransferThreadAsync.cpp
@@ -620,9 +620,16 @@ void TransferThreadAsync::ifCanStartTransfer()
                         return;
                     }
                 }
-            char buf[PATH_MAX];
-            const ssize_t s=readlink(TransferThread::internalStringTostring(source).c_str(),buf,sizeof(buf));
-            buf[s]=0x00;
+            std::vector<char> buf(512);
+            ssize_t s=0;
+            do {
+              buf.resize(buf.size()*2);
+              s=readlink(TransferThread::internalStringTostring(source).c_str(),buf.data(),buf.size());
+            } while (s == buf.size());
+            if (s!=-1) {
+              buf.resize(s + 1);
+              buf[s]='\0';
+            }
             if(s<0)
             {
                 const int terr=errno;
@@ -638,12 +645,12 @@ void TransferThreadAsync::ifCanStartTransfer()
             }
             else
             {
-                if(symlink(buf,TransferThread::internalStringTostring(destination).c_str())!=0)
+                if(symlink(buf.data(),TransferThread::internalStringTostring(destination).c_str())!=0)
                 {
                     const int terr=errno;
                     const std::string &strError=strerror(terr);
                     ULTRACOPIER_DEBUGCONSOLE(Ultracopier::DebugLevel_Warning,"["+std::to_string(id)+"] stop copy in error "+
-                                             buf+"->"+TransferThread::internalStringTostring(destination)+
+                                             buf.data()+"->"+TransferThread::internalStringTostring(destination)+
                                              " "+strError+"("+std::to_string(terr)+")"
                                              );
                     readError=true;