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Revert: Semmle: Protect against theoretical race in recursive d… (#3619) 

As discussed with @JelteF; #3559 caused consistent errors on BSD (OSX). Given a group of people use this environment to develop on it is an undesirable change.

This reverts commit ca8f7119fe.
pull/3629/head
Nils Dijk 2020-03-18 13:48:05 +01:00 committed by GitHub
parent e5a2bbb2bd
commit 6ff79c5ea9
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 84 additions and 81 deletions
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165
src/backend/distributed/worker/worker_partition_protocol.c
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@ -85,8 +85,7 @@ static uint32 RangePartitionId(Datum partitionValue, Oid partitionCollation,
static uint32 HashPartitionId(Datum partitionValue, Oid partitionCollation,
const void *context);
static StringInfo UserPartitionFilename(StringInfo directoryName, uint32 partitionId);
static bool TryUnlink(const char *filename);
static bool TryRmdir(const char *filename);
static bool FileIsLink(const char *filename, struct stat filestat);
/* exports for SQL callable functions */
@ -689,6 +688,25 @@ CitusCreateDirectory(StringInfo directoryName)
}
#ifdef WIN32
static bool
FileIsLink(char *filename, struct stat filestat)
{
return pgwin32_is_junction(filename);
}
#else
static bool
FileIsLink(const char *filename, struct stat filestat)
{
return S_ISLNK(filestat.st_mode);
}
#endif
/*
* CitusRemoveDirectory first checks if the given directory exists. If it does, the
* function recursively deletes the contents of the given directory, and then
@ -701,102 +719,87 @@ CitusRemoveDirectory(const char *filename)
/* files may be added during execution, loop when that occurs */
while (true)
{
if (TryUnlink(filename) || TryRmdir(filename))
struct stat fileStat;
int removed = 0;
int statOK = stat(filename, &fileStat);
if (statOK < 0)
{
return;
if (errno == ENOENT)
{
return; /* if file does not exist, return */
}
else
{
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m", filename)));
}
}
/*
* If both of these failed then filename is a non empty directory.
* Iterate over all its contents and for each content, recurse into
* this function. Also, make sure that we do not recurse into symbolic
* links.
* If this is a directory, iterate over all its contents and for each
* content, recurse into this function. Also, make sure that we do not
* recurse into symbolic links.
*/
const char *directoryName = filename;
if (S_ISDIR(fileStat.st_mode) && !FileIsLink(filename, fileStat))
{
const char *directoryName = filename;
DIR *directory = AllocateDir(directoryName);
if (errno == ENOENT)
{
/* If directory was removed from under us we're done */
return;
}
if (errno == ENOTDIR)
{
/* If directory changed to a file underneath us, loop again to remove it with unlink */
continue;
DIR *directory = AllocateDir(directoryName);
if (directory == NULL)
{
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
directoryName)));
}
StringInfo fullFilename = makeStringInfo();
struct dirent *directoryEntry = ReadDir(directory, directoryName);
for (; directoryEntry != NULL; directoryEntry = ReadDir(directory,
directoryName))
{
const char *baseFilename = directoryEntry->d_name;
/* if system file, skip it */
if (strncmp(baseFilename, ".", MAXPGPATH) == 0 ||
strncmp(baseFilename, "..", MAXPGPATH) == 0)
{
continue;
}
resetStringInfo(fullFilename);
appendStringInfo(fullFilename, "%s/%s", directoryName, baseFilename);
CitusRemoveDirectory(fullFilename->data);
}
FreeStringInfo(fullFilename);
FreeDir(directory);
}
/* ReadDir handles other errno from AllocateDir */
struct dirent *directoryEntry = ReadDir(directory, directoryName);
StringInfo fullFilename = makeStringInfo();
for (; directoryEntry != NULL; directoryEntry = ReadDir(directory,
directoryName))
/* we now have an empty directory or a regular file, remove it */
if (S_ISDIR(fileStat.st_mode))
{
const char *baseFilename = directoryEntry->d_name;
removed = rmdir(filename);
/* if system file, skip it */
if (strncmp(baseFilename, ".", MAXPGPATH) == 0 ||
strncmp(baseFilename, "..", MAXPGPATH) == 0)
if (errno == ENOTEMPTY || errno == EEXIST)
{
continue;
}
resetStringInfo(fullFilename);
appendStringInfo(fullFilename, "%s/%s", directoryName, baseFilename);
CitusRemoveDirectory(fullFilename->data);
}
else
{
removed = unlink(filename);
}
FreeStringInfo(fullFilename);
FreeDir(directory);
}
}
if (removed != 0 && errno != ENOENT)
{
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m", filename)));
}
/*
* TryUnlink returns true if file is removed and false if the file is a
* directory. If an error occurs trying to remove the file this function calls
* ereport.
*/
static bool
TryUnlink(const char *filename)
{
errno = 0;
int exitcode = unlink(filename);
if (exitcode == 0 || errno == ENOENT)
{
return true;
return;
}
if (errno == EISDIR)
{
return false;
}
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m", filename)));
}
/*
* TryRmdir returns true if the directory is removed. It returns false if the
* filename points to a file or symlink. It also returns false if the directory
* is not empty. The difference in these cases can be found by checking errno.
* For all other errors ereport is called.
*/
static bool
TryRmdir(const char *filename)
{
errno = 0;
int exitcode = rmdir(filename);
if (exitcode == 0 || errno == ENOENT)
{
return true;
}
if (errno == ENOTDIR || errno == ENOTEMPTY || errno == EEXIST)
{
return false;
}
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not remove directory \"%s\": %m", filename)));
}