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8223699: cleanup perfMemory_aix.cpp O_NOFOLLOW coding on aix
Reviewed-by: lucy, mdoerr
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MBaesken committed Jan 28, 2020
1 parent 0b9ff0c commit cd01fa372e6c53911bcf4a3608c2f75234285d71
Showing with 7 additions and 116 deletions.
  1. +7 −116 src/hotspot/os/aix/perfMemory_aix.cpp
@@ -1,6 +1,6 @@
/*
* Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2018 SAP SE. All rights reserved.
* Copyright (c) 2001, 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2020 SAP SE. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -98,8 +98,8 @@ static void save_memory_to_file(char* addr, size_t size) {

int result;

RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
result);;
RESTARTABLE(os::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
result);
if (result == OS_ERR) {
if (PrintMiscellaneous && Verbose) {
warning("Could not create Perfdata save file: %s: %s\n",
@@ -248,7 +248,6 @@ static bool is_directory_secure(const char* path) {
return is_statbuf_secure(&statbuf);
}

// (Taken over from Solaris to support the O_NOFOLLOW case on AIX.)
// Check if the given directory file descriptor is considered a secure
// directory for the backing store files. Returns true if the directory
// exists and is considered a secure location. Returns false if the path
@@ -290,89 +289,6 @@ static bool is_same_fsobject(int fd1, int fd2) {
}
}

// Helper functions for open without O_NOFOLLOW which is not present on AIX 5.3/6.1.
// We use the jdk6 implementation here.
#ifndef O_NOFOLLOW
// The O_NOFOLLOW oflag doesn't exist before solaris 5.10, this is to simulate that behaviour
// was done in jdk 5/6 hotspot by Oracle this way
static int open_o_nofollow_impl(const char* path, int oflag, mode_t mode, bool use_mode) {
struct stat orig_st;
struct stat new_st;
bool create;
int error;
int fd;
int result;

create = false;

RESTARTABLE(::lstat(path, &orig_st), result);

if (result == OS_ERR) {
if (errno == ENOENT && (oflag & O_CREAT) != 0) {
// File doesn't exist, but_we want to create it, add O_EXCL flag
// to make sure no-one creates it (or a symlink) before us
// This works as we expect with symlinks, from posix man page:
// 'If O_EXCL and O_CREAT are set, and path names a symbolic
// link, open() shall fail and set errno to [EEXIST]'.
oflag |= O_EXCL;
create = true;
} else {
// File doesn't exist, and we are not creating it.
return OS_ERR;
}
} else {
// lstat success, check if existing file is a link.
if ((orig_st.st_mode & S_IFMT) == S_IFLNK) {
// File is a symlink.
errno = ELOOP;
return OS_ERR;
}
}

if (use_mode == true) {
RESTARTABLE(::open(path, oflag, mode), fd);
} else {
RESTARTABLE(::open(path, oflag), fd);
}

if (fd == OS_ERR) {
return fd;
}

// Can't do inode checks on before/after if we created the file.
if (create == false) {
RESTARTABLE(::fstat(fd, &new_st), result);
if (result == OS_ERR) {
// Keep errno from fstat, in case close also fails.
error = errno;
::close(fd);
errno = error;
return OS_ERR;
}

if (orig_st.st_dev != new_st.st_dev || orig_st.st_ino != new_st.st_ino) {
// File was tampered with during race window.
::close(fd);
errno = EEXIST;
if (PrintMiscellaneous && Verbose) {
warning("possible file tampering attempt detected when opening %s", path);
}
return OS_ERR;
}
}

return fd;
}

static int open_o_nofollow(const char* path, int oflag, mode_t mode) {
return open_o_nofollow_impl(path, oflag, mode, true);
}

static int open_o_nofollow(const char* path, int oflag) {
return open_o_nofollow_impl(path, oflag, 0, false);
}
#endif

// Open the directory of the given path and validate it.
// Return a DIR * of the open directory.
static DIR *open_directory_secure(const char* dirname) {
@@ -383,15 +299,7 @@ static DIR *open_directory_secure(const char* dirname) {
// calling opendir() and is_directory_secure() does.
int result;
DIR *dirp = NULL;

// No O_NOFOLLOW defined at buildtime, and it is not documented for open;
// so provide a workaround in this case.
#ifdef O_NOFOLLOW
RESTARTABLE(::open(dirname, O_RDONLY|O_NOFOLLOW), result);
#else
// workaround (jdk6 coding)
result = open_o_nofollow(dirname, O_RDONLY);
#endif

if (result == OS_ERR) {
// Directory doesn't exist or is a symlink, so there is nothing to cleanup.
@@ -879,15 +787,7 @@ static int create_sharedmem_resources(const char* dirname, const char* filename,
// Cannot use O_TRUNC here; truncation of an existing file has to happen
// after the is_file_secure() check below.
int result;

// No O_NOFOLLOW defined at buildtime, and it is not documented for open;
// so provide a workaround in this case.
#ifdef O_NOFOLLOW
RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_NOFOLLOW, S_IREAD|S_IWRITE), result);
#else
// workaround function (jdk6 code)
result = open_o_nofollow(filename, O_RDWR|O_CREAT, S_IREAD|S_IWRITE);
#endif
RESTARTABLE(os::open(filename, O_RDWR|O_CREAT|O_NOFOLLOW, S_IREAD|S_IWRITE), result);

if (result == OS_ERR) {
if (PrintMiscellaneous && Verbose) {
@@ -944,12 +844,8 @@ static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {

// open the file
int result;
// provide a workaround in case no O_NOFOLLOW is defined at buildtime
#ifdef O_NOFOLLOW
RESTARTABLE(::open(filename, oflags), result);
#else
result = open_o_nofollow(filename, oflags);
#endif
RESTARTABLE(os::open(filename, oflags, 0), result);

if (result == OS_ERR) {
if (errno == ENOENT) {
THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
@@ -1137,12 +1033,7 @@ static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemor
// constructs for the file and the shared memory mapping.
if (mode == PerfMemory::PERF_MODE_RO) {
mmap_prot = PROT_READ;
// No O_NOFOLLOW defined at buildtime, and it is not documented for open.
#ifdef O_NOFOLLOW
file_flags = O_RDONLY | O_NOFOLLOW;
#else
file_flags = O_RDONLY;
#endif
}
else if (mode == PerfMemory::PERF_MODE_RW) {
#ifdef LATER

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