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8229872: (fs) Increase buffer size used with getmntent

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Dynamically allocate memory for getmntent

Reviewed-by: alanb
This commit is contained in:
Vladimir Kempik 2019-09-24 14:54:57 +03:00
parent 628283fe53
commit 67ad501e5b
5 changed files with 89 additions and 9 deletions
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20
src/java.base/linux/classes/sun/nio/fs/LinuxFileSystem.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2019, Oracle and/or its affiliates. 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
@ -79,10 +79,26 @@ class LinuxFileSystem extends UnixFileSystem {
ArrayList<UnixMountEntry> entries = new ArrayList<>();
try {
long fp = setmntent(Util.toBytes(fstab), Util.toBytes("r"));
int maxLineSize = 1024;
try {
for (;;) {
int lineSize = getlinelen(fp);
if (lineSize == -1)
break;
if (lineSize > maxLineSize)
maxLineSize = lineSize;
}
} catch (UnixException x) {
// nothing we need to do
} finally {
rewind(fp);
}
try {
for (;;) {
UnixMountEntry entry = new UnixMountEntry();
int res = getmntent(fp, entry);
// count in NUL character at the end
int res = getmntent(fp, entry, maxLineSize + 1);
if (res < 0)
break;
entries.add(entry);

12
src/java.base/linux/classes/sun/nio/fs/LinuxNativeDispatcher.java
View file

@ -51,7 +51,17 @@ class LinuxNativeDispatcher extends UnixNativeDispatcher {
/**
* int getmntent(FILE *fp, struct mnttab *mp, int len);
*/
static native int getmntent(long fp, UnixMountEntry entry)
static int getmntent(long fp, UnixMountEntry entry, int buflen) throws UnixException {
NativeBuffer buffer = NativeBuffers.getNativeBuffer(buflen);
try {
return getmntent0(fp, entry, buffer.address(), buflen);
} finally {
buffer.release();
}
}
static native int getmntent0(long fp, UnixMountEntry entry, long buffer, int bufLen)
throws UnixException;
/**

11
src/java.base/linux/native/libnio/fs/LinuxNativeDispatcher.c
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2019, Oracle and/or its affiliates. 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
@ -169,12 +169,11 @@ Java_sun_nio_fs_LinuxNativeDispatcher_setmntent0(JNIEnv* env, jclass this, jlong
}
JNIEXPORT jint JNICALL
Java_sun_nio_fs_LinuxNativeDispatcher_getmntent(JNIEnv* env, jclass this,
jlong value, jobject entry)
Java_sun_nio_fs_LinuxNativeDispatcher_getmntent0(JNIEnv* env, jclass this,
jlong value, jobject entry, jlong buffer, jint bufLen)
{
struct mntent ent;
char buf[1024];
int buflen = sizeof(buf);
char * buf = (char*)jlong_to_ptr(buffer);
struct mntent* m;
FILE* fp = jlong_to_ptr(value);
jsize len;
@ -184,7 +183,7 @@ Java_sun_nio_fs_LinuxNativeDispatcher_getmntent(JNIEnv* env, jclass this,
char* fstype;
char* options;
m = getmntent_r(fp, &ent, (char*)&buf, buflen);
m = getmntent_r(fp, &ent, buf, (int)bufLen);
if (m == NULL)
return -1;
name = m->mnt_fsname;