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Bug 281222 The file copy under unix can fail and produce zero sized file in some circumstances

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patch by wbonnet@on-x.com r=timeless sr=darin
This commit is contained in:
timeless%mozdev.org 2006-11-02 21:27:37 +00:00
parent cf33d376df
commit 7a5958dbf4
1 changed files with 115 additions and 41 deletions
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156
xpcom/obsolete/nsFileSpecUnix.cpp
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@ -21,6 +21,7 @@
*
* Contributor(s):
* Henry Sobotka <sobotka@axess.com>
* William Bonnet <wbonnet@on-x.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
@ -415,57 +416,130 @@ nsresult nsFileSpec::Rename(const char* inNewName)
return NS_OK;
} // nsFileSpec::Rename
//----------------------------------------------------------------------------------------
static int CrudeFileCopy_DoCopy(PRFileDesc * pFileDescIn, PRFileDesc * pFileDescOut, char * pBuf, long bufferSize)
//----------------------------------------------------------------------------------------
{
PRInt32 rbytes, wbytes; // Number of bytes read and written in copy loop
// Copy loop
//
// If EOF is reached and no data is available, PR_Read returns 0. A negative
// return value means an error occured
rbytes = PR_Read(pFileDescIn, pBuf, bufferSize);
if (rbytes < 0) // Test if read was unsuccessfull
{ // Error case
return -1; // Return an error
}
while (rbytes > 0) // While there is data to copy
{
// Data buffer size is only 1K ! fwrite function is able to write it in
// one call. According to the man page fwrite returns a number of elements
// written if an error occured. Thus there is no need to handle this case
// as a normal case. Written data cannot be smaller than rbytes.
wbytes = PR_Write(pFileDescOut, pBuf, rbytes); // Copy data to output file
if (wbytes != rbytes) // Test if all data was written
{ // No this an error
return -1; // Return an error
}
// Write is done, we try to get more data
rbytes = PR_Read(pFileDescIn, pBuf, bufferSize);
if (rbytes < 0) // Test if read was unsuccessful
{ // Error case
return -1; // Return an error
}
}
return 0; // Still here ? ok so it worked :)
} // nsFileSpec::CrudeFileCopy_DoCopy
//----------------------------------------------------------------------------------------
static int CrudeFileCopy(const char* in, const char* out)
//----------------------------------------------------------------------------------------
{
struct stat in_stat;
int stat_result = -1;
char buf[1024]; // Used as buffer for the copy loop
PRInt32 rbytes, wbytes; // Number of bytes read and written in copy loop
struct stat in_stat; // Stores informations from the stat syscall
int stat_result = -1, ret;
PRFileDesc * pFileDescIn, * pFileDescOut; // Src and dest pointers
char buf [1024];
FILE *ifp, *ofp;
int rbytes, wbytes;
// Check if the pointers to filenames are valid
NS_ASSERTION(in && out, "CrudeFileCopy should be called with pointers to filenames...");
if (!in || !out)
return -1;
// Check if the pointers are the same, if so, no need to copy A to A
if (in == out)
return 0;
stat_result = stat (in, &in_stat);
// Check if content of the pointers are the sames, if so, no need to copy A to A
if (strcmp(in,out) == 0)
return 0;
ifp = fopen (in, "r");
if (!ifp)
{
return -1;
}
// Retrieve the 'in' file attributes
stat_result = stat(in, &in_stat);
if(stat_result != 0)
{
// test if stat failed, it can happen if the file does not exist, is not
// readable or is not available ( can happen with NFS mounts )
return -1; // Return an error
}
ofp = fopen (out, "w");
if (!ofp)
{
fclose (ifp);
return -1;
}
// Open the input file for binary read
pFileDescIn = PR_Open(in, PR_RDONLY, 0444);
if (pFileDescIn == 0)
{
return -1; // Open failed, return an error
}
while ((rbytes = fread (buf, 1, sizeof(buf), ifp)) > 0)
{
while (rbytes > 0)
{
if ( (wbytes = fwrite (buf, 1, rbytes, ofp)) < 0 )
{
fclose (ofp);
fclose (ifp);
unlink(out);
return -1;
}
rbytes -= wbytes;
}
}
fclose (ofp);
fclose (ifp);
// Open the output file for binary write
pFileDescOut = PR_Open(out, PR_WRONLY | PR_CREATE_FILE, 0600);
if (pFileDescOut == 0)
{
// Open failed, need to close input file, then return an error
PR_Close(pFileDescOut); // Close the output file
return -1; // Open failed, return an error
}
if (stat_result == 0)
chmod (out, in_stat.st_mode & 0777);
// Copy the data
if (CrudeFileCopy_DoCopy(pFileDescIn, pFileDescOut, buf, sizeof(buf)) != 0)
{ // Error case
PR_Close(pFileDescOut); // Close output file
PR_Close(pFileDescIn); // Close input file
PR_Delete(out); // Destroy output file
return -1; // Return an error
}
return 0;
} // nsFileSpec::Rename
// There is no need for error handling here. This should have worked, but even
// if it fails, the data are now copied to destination, thus there is no need
// for the function to fail on the input file error
PR_Close(pFileDescIn);
// It is better to call fsync and test return code before exiting to be sure
// data are actually written on disk. Data loss can happen with NFS mounts
if (PR_Sync(pFileDescOut) != PR_SUCCESS)
{ // Test if the fsync function succeeded
PR_Close(pFileDescOut); // Close output file
PR_Delete(out); // Destroy output file
return -1; // Return an error
}
// Copy is done, close both file
if (PR_Close(pFileDescOut) != PR_SUCCESS) // Close output file
{ // Output file was not closed :(
PR_Delete(out); // Destroy output file
return -1; // Return an error
}
ret = chmod(out, in_stat.st_mode & 0777); // Set the new file file mode
if (ret != 0) // Test if the chmod function succeeded
{
PR_Delete(out); // Destroy output file
return -1; // Return an error
}
return 0; // Still here ? ok so it worked :)
} // nsFileSpec::CrudeFileCopy
//----------------------------------------------------------------------------------------
nsresult nsFileSpec::CopyToDir(const nsFileSpec& inParentDirectory) const
@ -505,10 +579,10 @@ nsresult nsFileSpec::MoveToDir(const nsFileSpec& inNewParentDirectory)
if (result == NS_OK)
{
// cast to fix const-ness
((nsFileSpec*)this)->Delete(PR_FALSE);
((nsFileSpec*)this)->Delete(PR_FALSE);
*this = inNewParentDirectory + GetLeafName();
}
}
}
return result;
}