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Overview
Comment:Cleaning up some source comments & such. Also modified a memory block to be on the heap instead of the stack.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | bad-winsymlink
Files: files | file ages | folders
SHA1:30ff96e7a5c4ff78e69655bfac0c9282bfef33d5
User & Date: sdr 2014-09-21 02:05:03
Context
2014-09-21
03:05
Merging latest updates from trunk. check-in: 0ee7e92222 user: sdr tags: bad-winsymlink
02:29
Merged updates from trunk, but somehow managed to clear execute permissions on a bunch of files. Moved to bad-winsymlink to try again. Closed-Leaf check-in: dbe7bcc7cf user: sdr tags: bad-winsymlink
02:05
Cleaning up some source comments & such. Also modified a memory block to be on the heap instead of the stack. check-in: 30ff96e7a5 user: sdr tags: bad-winsymlink
2014-09-20
18:41
Changed name of checked_symlink_create to create_symlink_or_file as it is more accurate / descriptive. Also changed some parameter names, and fixed a couple spelling errors (accidentally typed blog instead of blob and never compiled; oops). check-in: 31b0a9d737 user: sdr tags: bad-winsymlink
Changes
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Changes to src/file.c.

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    Blob content;
    blob_set(&content, zTargetFile);
    blob_write_to_file(&content, zLinkFile);
    blob_reset(&content);
  }
}













void create_symlink_or_file(int mayNeedDelete, int needLink, int mayBeLink, Blob* blob, const char* zName){
  if (mayNeedDelete && (needLink || mayBeLink))
    link_delete(zName);
  if (needLink)
    symlink_create(blob_str(blob), zName);
  else
    blob_write_to_file(blob, zName);







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    Blob content;
    blob_set(&content, zTargetFile);
    blob_write_to_file(&content, zLinkFile);
    blob_reset(&content);
  }
}

/*
** This code is used in multiple places around fossil. Rather than having
** four or five slightly different cut & paste chunks of code, this function
** does the task of deleting a (possible) link (if necessary) and then
** either creating a link or a file based on input parameters.
** mayNeedDelete is true if we might need to call link_delete, false otherwise.
** needLink is true if we need to create a symlink, false otherwise.
** mayBeLink is true if zName might be a symlink based on the state of the
** checkout and/or file system, false otherwise.
** blob is the binary data to either write as a symlink or as a file.
** zName is the name of the file or symlink to write.
*/
void create_symlink_or_file(int mayNeedDelete, int needLink, int mayBeLink, Blob* blob, const char* zName){
  if (mayNeedDelete && (needLink || mayBeLink))
    link_delete(zName);
  if (needLink)
    symlink_create(blob_str(blob), zName);
  else
    blob_write_to_file(blob, zName);

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#include <versionhelpers.h>
#include "winfile.h"

#ifndef LABEL_SECURITY_INFORMATION
#   define LABEL_SECURITY_INFORMATION (0x00000010L)
#endif

/* copy & paste from ntifs.h */









typedef struct _REPARSE_DATA_BUFFER {
  ULONG  ReparseTag;
  USHORT ReparseDataLength;
  USHORT Reserved;
  union {
    struct {
      USHORT SubstituteNameOffset;
      USHORT SubstituteNameLength;
      USHORT PrintNameOffset;
      USHORT PrintNameLength;
      ULONG  Flags;
      WCHAR  PathBuffer[1];
    } SymbolicLinkReparseBuffer;
    struct {
      USHORT SubstituteNameOffset;
      USHORT SubstituteNameLength;
      USHORT PrintNameOffset;
      USHORT PrintNameLength;
      WCHAR  PathBuffer[1];
    } MountPointReparseBuffer;
    struct {
      UCHAR DataBuffer[1];
    } GenericReparseBuffer;
  };
} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;

#define LINK_BUFFER_SIZE 1024







int win32_lstat(const wchar_t *zFilename, struct fossilStat *buf){
  WIN32_FILE_ATTRIBUTE_DATA attr;
  int rc = GetFileAttributesExW(zFilename, GetFileExInfoStandard, &attr);
  if( rc ){





    char *tname = fossil_filename_to_utf8(zFilename);
    char tlink[LINK_BUFFER_SIZE];
    ssize_t tlen = win32_readlink(tname, tlink, sizeof(tlink));



    ULARGE_INTEGER ull;


    buf->st_mode = (tlen > 0) ? S_IFLNK :
                   ((attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ?
                     S_IFDIR : S_IFREG);
    
    buf->st_size = (((i64)attr.nFileSizeHigh)<<32) | attr.nFileSizeLow;
    
    ull.LowPart = attr.ftLastWriteTime.dwLowDateTime;
................................................................................
    ull.HighPart = attr.ftLastWriteTime.dwHighDateTime;
    buf->st_mtime = ull.QuadPart / 10000000ULL - 11644473600ULL;
  }
  return !rc;
}

/*
** Fill stat buf with information received from stat() or lstat().
** lstat() is called on Unix if isWd is TRUE and allow-symlinks setting is on.
**





*/
int win32_stat(const wchar_t *zFilename, struct fossilStat *buf){
  int rc;
  HANDLE file;
  wchar_t nextFilename[LINK_BUFFER_SIZE];
  DWORD len;

  
  while (1){

    rc = win32_lstat(zFilename, buf);

    /* exit on error or not link */
    if ((rc != 0) || (buf->st_mode != S_IFLNK))
      break;

    /* it is a link, so open the linked file */      
    file = CreateFileW(zFilename, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);
    if ((file == NULL) || (file == INVALID_HANDLE_VALUE)){
      rc = -1;
      break;
    }

    /* get the final path name and close the handle */
    len = GetFinalPathNameByHandleW(file, nextFilename, LINK_BUFFER_SIZE - 1, 0);
    CloseHandle(file);
    
    /* if any problems getting the final path name error so exit */
    if ((len <= 0) || (len > LINK_BUFFER_SIZE - 1)){
      rc = -1;
      break;
    }
    
    /* prepare to try again just in case we have a chain to follow */
    /* this shouldn't happen, but just trying to be safe */
    zFilename = nextFilename;
  }
  
  return rc;
}






ssize_t win32_readlink(const char *path, char *buf, size_t bufsiz){
  /* assume we're going to fail */
  ssize_t rv = -1;
  
  /* does path reference a reparse point? */
  WIN32_FILE_ATTRIBUTE_DATA attr;
  int rc = GetFileAttributesEx(path, GetFileExInfoStandard, &attr);
................................................................................
    /* since it is a reparse point, open it */
    HANDLE file = CreateFile(path, GENERIC_READ, 0, NULL, OPEN_EXISTING, 
      FILE_FLAG_OPEN_REPARSE_POINT, NULL);      
    if ((file != NULL) && (file != INVALID_HANDLE_VALUE)){

      /* use DeviceIoControl to get the reparse point data */
    
      union {
        REPARSE_DATA_BUFFER data;
        char buffer[sizeof(REPARSE_DATA_BUFFER) + LINK_BUFFER_SIZE * sizeof(wchar_t)];
      } u;

      DWORD bytes;
      
      u.data.ReparseTag = IO_REPARSE_TAG_SYMLINK;
      u.data.ReparseDataLength = 0;
      u.data.Reserved = 0;
    
      int rc = DeviceIoControl(file, FSCTL_GET_REPARSE_POINT, NULL, 0,
        &u, sizeof(u), &bytes, NULL);


      /* did the reparse point data fit into the desired buffer? */
      if (rc && (bytes < sizeof(u))){

        /* it fit, so setup the print name for further processing */
        USHORT
          offset = u.data.SymbolicLinkReparseBuffer.PrintNameOffset / sizeof(wchar_t),
          length = u.data.SymbolicLinkReparseBuffer.PrintNameLength / sizeof(wchar_t);
        char *temp;
        u.data.SymbolicLinkReparseBuffer.PathBuffer[offset + length] = 0;

        /* convert the filename to utf8, copy it, and discard the converted copy */
        temp = fossil_filename_to_utf8(u.data.SymbolicLinkReparseBuffer.PathBuffer + offset);
        rv = strlen(temp);
        if (rv >= bufsiz)
          rv = bufsiz;
        memcpy(buf, temp, rv);
        fossil_filename_free(temp);
      }


      
      /* all done, close the reparse point */
      CloseHandle(file);
    }
  }

  return rv;
}










int win32_unlink_rmdir(const wchar_t *zFilename){
  int rc = -1;
  fossilStat stat;
  if (win32_stat(zFilename, &stat) == 0){
    if (stat.st_mode == S_IFDIR)
      rc = RemoveDirectoryW(zFilename) ? 0 : -1;
    else
      rc = DeleteFileW(zFilename) ? 0 : -1;
  }
  return rc;
}










int win32_symlink(const char *oldpath, const char *newpath){
  fossilStat stat;
  int created = 0;
  DWORD flags = 0;
  wchar_t *zMbcs;

  /* does oldpath exist? is it a dir or a file? */  
................................................................................
  fossil_filename_free(zMbcs);

  /* remove newpath before creating the symlink */
  zMbcs = fossil_utf8_to_filename(newpath);
  win32_unlink_rmdir(zMbcs);
  fossil_filename_free(zMbcs);

  if (CreateSymbolicLink(newpath, oldpath, flags))
    created = 1;

  /* if the symlink was not created, create a plain text file */
  if (!created){
    Blob content;
    blob_set(&content, oldpath);
    blob_write_to_file(&content, newpath);
    blob_reset(&content);
    created = 1;
  }
  
  return created ? 0 : -1;
}









int win32_symlinks_supported(){
  TOKEN_PRIVILEGES tp;
  LUID luid;
  HANDLE process, token;
  DWORD status;

  /* symlinks only supported on vista or greater */







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#include <versionhelpers.h>
#include "winfile.h"

#ifndef LABEL_SECURITY_INFORMATION
#   define LABEL_SECURITY_INFORMATION (0x00000010L)
#endif

/* a couple defines to make the borrowed struct below compile */
#define _ANONYMOUS_UNION
#define DUMMYUNIONNAME

/*
** this structure copied on 20 Sept 2014 from
** https://reactos-mirror.googlecode.com/svn-history/r54752/branches/usb-bringup/include/ddk/ntifs.h
** which is a public domain file from the ReactOS DDK package.
*/

typedef struct _REPARSE_DATA_BUFFER {
  ULONG ReparseTag;
  USHORT ReparseDataLength;
  USHORT Reserved;
  _ANONYMOUS_UNION union {
    struct {
      USHORT SubstituteNameOffset;
      USHORT SubstituteNameLength;
      USHORT PrintNameOffset;
      USHORT PrintNameLength;
      ULONG Flags;
      WCHAR PathBuffer[1];
    } SymbolicLinkReparseBuffer;
    struct {
      USHORT SubstituteNameOffset;
      USHORT SubstituteNameLength;
      USHORT PrintNameOffset;
      USHORT PrintNameLength;
      WCHAR PathBuffer[1];
    } MountPointReparseBuffer;
    struct {
      UCHAR DataBuffer[1];
    } GenericReparseBuffer;
  } DUMMYUNIONNAME;
} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;

#define LINK_BUFFER_SIZE 1024

/*
** Fill stat buf with information received from GetFileAttributesExW().
** Does not follow symbolic links, returning instead information about
** the link itself.
** Returns 0 on success, 1 on failure.
*/
int win32_lstat(const wchar_t *zFilename, struct fossilStat *buf){
  WIN32_FILE_ATTRIBUTE_DATA attr;
  int rc = GetFileAttributesExW(zFilename, GetFileExInfoStandard, &attr);
  if( rc ){
    ssize_t tlen = 0; /* assume it is not a symbolic link */
    
    /* if it is a reparse point it *might* be a symbolic link */
    /* so defer to win32_readlink to actually check */
    if (attr.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT){
      char *tname = fossil_filename_to_utf8(zFilename);
      char tlink[LINK_BUFFER_SIZE];
      tlen = win32_readlink(tname, tlink, sizeof(tlink));
      fossil_filename_free(tname);
    }
    
    ULARGE_INTEGER ull;

    /* if a link was retrieved, it is a symlink, otherwise a dir or file */
    buf->st_mode = (tlen > 0) ? S_IFLNK :
                   ((attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ?
                     S_IFDIR : S_IFREG);
    
    buf->st_size = (((i64)attr.nFileSizeHigh)<<32) | attr.nFileSizeLow;
    
    ull.LowPart = attr.ftLastWriteTime.dwLowDateTime;
................................................................................
    ull.HighPart = attr.ftLastWriteTime.dwHighDateTime;
    buf->st_mtime = ull.QuadPart / 10000000ULL - 11644473600ULL;
  }
  return !rc;
}

/*
** Fill stat buf with information received from win32_lstat().
** If a symbolic link is found, follow it and return information about
** the target, repeating until an actual target is found.
** Limit the number of loop iterations so as to avoid an infinite loop
** due to circular links. This should never happen because 
** GetFinalPathNameByHandleW() should always preclude that need, but being
** prepared to loop seems prudent, or at least not harmful.
** Returns 0 on success, 1 on failure.
*/
int win32_stat(const wchar_t *zFilename, struct fossilStat *buf){
  int rc;
  HANDLE file;
  wchar_t nextFilename[LINK_BUFFER_SIZE];
  DWORD len;
  int iterationsRemaining = 8; /* 8 is arbitrary, can be modified as needed */
  

  while (iterationsRemaining-- > 0){
    rc = win32_lstat(zFilename, buf);

    /* exit on error or not link */
    if ((rc != 0) || (buf->st_mode != S_IFLNK))
      break;

    /* it is a link, so open the linked file */      
    file = CreateFileW(zFilename, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);
    if ((file == NULL) || (file == INVALID_HANDLE_VALUE)){
      rc = 1;
      break;
    }

    /* get the final path name and close the handle */
    len = GetFinalPathNameByHandleW(file, nextFilename, LINK_BUFFER_SIZE - 1, 0);
    CloseHandle(file);
    
    /* if any problems getting the final path name error so exit */
    if ((len <= 0) || (len > LINK_BUFFER_SIZE - 1)){
      rc = 1;
      break;
    }
    
    /* prepare to try again just in case we have a chain to follow */
    /* this shouldn't happen, but just trying to be safe */
    zFilename = nextFilename;
  }
  
  return rc;
}

/*
** An implementation of a posix-like readlink function for win32.
** Copies the target of a symbolic link to buf if possible.
** Returns the length of the link copied to buf on success, -1 on failure.
*/
ssize_t win32_readlink(const char *path, char *buf, size_t bufsiz){
  /* assume we're going to fail */
  ssize_t rv = -1;
  
  /* does path reference a reparse point? */
  WIN32_FILE_ATTRIBUTE_DATA attr;
  int rc = GetFileAttributesEx(path, GetFileExInfoStandard, &attr);
................................................................................
    /* since it is a reparse point, open it */
    HANDLE file = CreateFile(path, GENERIC_READ, 0, NULL, OPEN_EXISTING, 
      FILE_FLAG_OPEN_REPARSE_POINT, NULL);      
    if ((file != NULL) && (file != INVALID_HANDLE_VALUE)){

      /* use DeviceIoControl to get the reparse point data */
    


      int data_size = sizeof(REPARSE_DATA_BUFFER) + LINK_BUFFER_SIZE * sizeof(wchar_t);

      REPARSE_DATA_BUFFER* data = fossil_malloc(data_size);
      DWORD data_used;
    
      data->ReparseTag = IO_REPARSE_TAG_SYMLINK;
      data->ReparseDataLength = 0;
      data->Reserved = 0;
    
      int rc = DeviceIoControl(file, FSCTL_GET_REPARSE_POINT, NULL, 0,

        data, data_size, &data_used, NULL);

      /* did the reparse point data fit into the desired buffer? */

      if (rc && (data_used < data_size)){
        /* it fit, so setup the print name for further processing */
        USHORT
          offset = data->SymbolicLinkReparseBuffer.PrintNameOffset / sizeof(wchar_t),
          length = data->SymbolicLinkReparseBuffer.PrintNameLength / sizeof(wchar_t);
        char *temp;
        data->SymbolicLinkReparseBuffer.PathBuffer[offset + length] = 0;

        /* convert the filename to utf8, copy it, and discard the converted copy */
        temp = fossil_filename_to_utf8(data->SymbolicLinkReparseBuffer.PathBuffer + offset);
        rv = strlen(temp);
        if (rv >= bufsiz)
          rv = bufsiz;
        memcpy(buf, temp, rv);
        fossil_filename_free(temp);
      }
      
      fossil_free(data);
      
      /* all done, close the reparse point */
      CloseHandle(file);
    }
  }

  return rv;
}

/*
** Either unlink a file or remove a directory on win32 systems.
** To delete a symlink on a posix system, you simply unlink the entry.
** Unfortunately for our purposes, win32 differentiates between symlinks for
** files and for directories. Thus you must unlink a file symlink or rmdir a
** directory symlink. This is a convenience function used when we know we're
** deleting a symlink of some type.
** Returns 0 on success, 1 on failure.
*/
int win32_unlink_rmdir(const wchar_t *zFilename){
  int rc = 0;
  fossilStat stat;
  if (win32_stat(zFilename, &stat) == 0){
    if (stat.st_mode == S_IFDIR)
      rc = RemoveDirectoryW(zFilename);
    else
      rc = DeleteFileW(zFilename);
  }
  return !rc;
}

/*
** An implementation of a posix-like symlink function for win32.
** Attempts to create a file or directory symlink based on the target.
** Defaults to a file symlink if the target does not exist / can't be checked.
** Finally, if the symlink cannot be created for whatever reason (perhaps
** newpath is on a network share or a FAT derived file system), default to
** creation of a text file with the context of the link.
** Returns 0 on success, 1 on failure.
*/
int win32_symlink(const char *oldpath, const char *newpath){
  fossilStat stat;
  int created = 0;
  DWORD flags = 0;
  wchar_t *zMbcs;

  /* does oldpath exist? is it a dir or a file? */  
................................................................................
  fossil_filename_free(zMbcs);

  /* remove newpath before creating the symlink */
  zMbcs = fossil_utf8_to_filename(newpath);
  win32_unlink_rmdir(zMbcs);
  fossil_filename_free(zMbcs);

  created = CreateSymbolicLink(newpath, oldpath, flags);


  /* if the symlink was not created, create a plain text file */
  if (!created){
    Blob content;
    blob_set(&content, oldpath);
    blob_write_to_file(&content, newpath);
    blob_reset(&content);
    created = 1;
  }
  
  return !created;
}

/*
** Check if symlinks are potentially supported on the current OS.
** Theoretically this code should work on any NT based version of windows
** but I have no way of testing that. The initial check for
** IsWindowsVistaOrGreater() should in theory eliminate any system prior to
** Windows Vista, but I have no way to test that at this time.
** Return 1 if supported, 0 if not.
*/
int win32_symlinks_supported(){
  TOKEN_PRIVILEGES tp;
  LUID luid;
  HANDLE process, token;
  DWORD status;

  /* symlinks only supported on vista or greater */