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6929479: Add a system property sun.zip.disableMemoryMapping to disable mmap use in ZipFile

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System property sun.zip.disableMemoryMapping to disable mmap use

Reviewed-by: alanb
This commit is contained in:
Xueming Shen 2010-03-11 14:06:09 -08:00
parent 63a75eead0
commit 57a26502f0
4 changed files with 105 additions and 69 deletions
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19
jdk/src/share/classes/java/util/zip/ZipFile.java
View File

@ -36,6 +36,8 @@ import java.util.Enumeration;
import java.util.Set;
import java.util.HashSet;
import java.util.NoSuchElementException;
import java.security.AccessController;
import sun.security.action.GetPropertyAction;
import static java.util.zip.ZipConstants64.*;
/**
@ -78,6 +80,17 @@ class ZipFile implements ZipConstants, Closeable {
private static native void initIDs();
private static final boolean usemmap;
static {
// A system prpperty to disable mmap use to avoid vm crash when
// in-use zip file is accidently overwritten by others.
String prop = AccessController.doPrivileged(
new GetPropertyAction("sun.zip.disableMemoryMapping"));
usemmap = (prop == null ||
!(prop.length() == 0 || prop.equalsIgnoreCase("true")));
}
/**
* Opens a zip file for reading.
*
@ -196,7 +209,7 @@ class ZipFile implements ZipConstants, Closeable {
throw new NullPointerException("charset is null");
this.zc = ZipCoder.get(charset);
long t0 = System.nanoTime();
jzfile = open(name, mode, file.lastModified());
jzfile = open(name, mode, file.lastModified(), usemmap);
sun.misc.PerfCounter.getZipFileOpenTime().addElapsedTimeFrom(t0);
sun.misc.PerfCounter.getZipFileCount().increment();
this.name = name;
@ -673,8 +686,8 @@ class ZipFile implements ZipConstants, Closeable {
}
private static native long open(String name, int mode, long lastModified)
throws IOException;
private static native long open(String name, int mode, long lastModified,
boolean usemmap) throws IOException;
private static native int getTotal(long jzfile);
private static native int read(long jzfile, long jzentry,
long pos, byte[] b, int off, int len);

5
jdk/src/share/native/java/util/zip/ZipFile.c
View File

@ -81,7 +81,8 @@ ThrowZipException(JNIEnv *env, const char *msg)
JNIEXPORT jlong JNICALL
Java_java_util_zip_ZipFile_open(JNIEnv *env, jclass cls, jstring name,
jint mode, jlong lastModified)
jint mode, jlong lastModified,
jboolean usemmap)
{
const char *path = JNU_GetStringPlatformChars(env, name, 0);
char *msg = 0;
@ -109,7 +110,7 @@ Java_java_util_zip_ZipFile_open(JNIEnv *env, jclass cls, jstring name,
goto finally;
}
#endif
zip = ZIP_Put_In_Cache(path, zfd, &msg, lastModified);
zip = ZIP_Put_In_Cache0(path, zfd, &msg, lastModified, usemmap);
}
if (zip != 0) {

140
jdk/src/share/native/java/util/zip/zip_util.c
View File

@ -251,11 +251,16 @@ freeZip(jzfile *zip)
if (zip->lock != NULL) MDESTROY(zip->lock);
free(zip->name);
freeCEN(zip);
#ifdef USE_MMAP
if (zip->maddr != NULL) munmap((char *)zip->maddr, zip->mlen);
#else
free(zip->cencache.data);
if (zip->usemmap) {
if (zip->maddr != NULL)
munmap((char *)zip->maddr, zip->mlen);
} else
#endif
{
free(zip->cencache.data);
}
if (zip->comment != NULL)
free(zip->comment);
if (zip->zfd != -1) ZFILE_Close(zip->zfd);
@ -585,49 +590,53 @@ readCEN(jzfile *zip, jint knownTotal)
ZIP_FORMAT_ERROR("invalid END header (bad central directory offset)");
#ifdef USE_MMAP
/* On Solaris & Linux prior to JDK 6, we used to mmap the whole jar file to
* read the jar file contents. However, this greatly increased the perceived
* footprint numbers because the mmap'ed pages were adding into the totals shown
* by 'ps' and 'top'. We switched to mmaping only the central directory of jar
* file while calling 'read' to read the rest of jar file. Here are a list of
* reasons apart from above of why we are doing so:
* 1. Greatly reduces mmap overhead after startup complete;
* 2. Avoids dual path code maintainance;
* 3. Greatly reduces risk of address space (not virtual memory) exhaustion.
*/
if (pagesize == 0) {
pagesize = (jlong)sysconf(_SC_PAGESIZE);
if (pagesize == 0) goto Catch;
}
if (cenpos > pagesize) {
offset = cenpos & ~(pagesize - 1);
} else {
offset = 0;
}
/* When we are not calling recursively, knownTotal is -1. */
if (knownTotal == -1) {
void* mappedAddr;
/* Mmap the CEN and END part only. We have to figure
out the page size in order to make offset to be multiples of
page size.
*/
zip->mlen = cenpos - offset + cenlen + endhdrlen;
zip->offset = offset;
mappedAddr = mmap64(0, zip->mlen, PROT_READ, MAP_SHARED, zip->zfd, (off64_t) offset);
zip->maddr = (mappedAddr == (void*) MAP_FAILED) ? NULL :
(unsigned char*)mappedAddr;
if (zip->maddr == NULL) {
jio_fprintf(stderr, "mmap failed for CEN and END part of zip file\n");
goto Catch;
if (zip->usemmap) {
/* On Solaris & Linux prior to JDK 6, we used to mmap the whole jar file to
* read the jar file contents. However, this greatly increased the perceived
* footprint numbers because the mmap'ed pages were adding into the totals shown
* by 'ps' and 'top'. We switched to mmaping only the central directory of jar
* file while calling 'read' to read the rest of jar file. Here are a list of
* reasons apart from above of why we are doing so:
* 1. Greatly reduces mmap overhead after startup complete;
* 2. Avoids dual path code maintainance;
* 3. Greatly reduces risk of address space (not virtual memory) exhaustion.
*/
if (pagesize == 0) {
pagesize = (jlong)sysconf(_SC_PAGESIZE);
if (pagesize == 0) goto Catch;
}
}
cenbuf = zip->maddr + cenpos - offset;
#else
if ((cenbuf = malloc((size_t) cenlen)) == NULL ||
(readFullyAt(zip->zfd, cenbuf, cenlen, cenpos) == -1))
goto Catch;
if (cenpos > pagesize) {
offset = cenpos & ~(pagesize - 1);
} else {
offset = 0;
}
/* When we are not calling recursively, knownTotal is -1. */
if (knownTotal == -1) {
void* mappedAddr;
/* Mmap the CEN and END part only. We have to figure
out the page size in order to make offset to be multiples of
page size.
*/
zip->mlen = cenpos - offset + cenlen + endhdrlen;
zip->offset = offset;
mappedAddr = mmap64(0, zip->mlen, PROT_READ, MAP_SHARED, zip->zfd, (off64_t) offset);
zip->maddr = (mappedAddr == (void*) MAP_FAILED) ? NULL :
(unsigned char*)mappedAddr;
if (zip->maddr == NULL) {
jio_fprintf(stderr, "mmap failed for CEN and END part of zip file\n");
goto Catch;
}
}
cenbuf = zip->maddr + cenpos - offset;
} else
#endif
{
if ((cenbuf = malloc((size_t) cenlen)) == NULL ||
(readFullyAt(zip->zfd, cenbuf, cenlen, cenpos) == -1))
goto Catch;
}
cenend = cenbuf + cenlen;
/* Initialize zip file data structures based on the total number
@ -700,9 +709,11 @@ readCEN(jzfile *zip, jint knownTotal)
cenpos = -1;
Finally:
#ifndef USE_MMAP
free(cenbuf);
#ifdef USE_MMAP
if (!zip->usemmap)
#endif
free(cenbuf);
return cenpos;
}
@ -782,8 +793,16 @@ ZIP_Get_From_Cache(const char *name, char **pmsg, jlong lastModified)
* If a zip error occurs, then *pmsg will be set to the error message text if
* pmsg != 0. Otherwise, *pmsg will be set to NULL.
*/
jzfile *
ZIP_Put_In_Cache(const char *name, ZFILE zfd, char **pmsg, jlong lastModified)
{
return ZIP_Put_In_Cache0(name, zfd, pmsg, lastModified, JNI_TRUE);
}
jzfile *
ZIP_Put_In_Cache0(const char *name, ZFILE zfd, char **pmsg, jlong lastModified,
jboolean usemmap)
{
static char errbuf[256];
jlong len;
@ -793,6 +812,9 @@ ZIP_Put_In_Cache(const char *name, ZFILE zfd, char **pmsg, jlong lastModified)
return NULL;
}
#ifdef USE_MMAP
zip->usemmap = usemmap;
#endif
zip->refs = 1;
zip->lastModified = lastModified;
@ -877,8 +899,6 @@ ZIP_Close(jzfile *zip)
return;
}
#ifndef USE_MMAP
/* Empirically, most CEN headers are smaller than this. */
#define AMPLE_CEN_HEADER_SIZE 160
@ -928,7 +948,6 @@ sequentialAccessReadCENHeader(jzfile *zip, jlong cenpos)
cache->pos = cenpos;
return cen;
}
#endif /* not USE_MMAP */
typedef enum { ACCESS_RANDOM, ACCESS_SEQUENTIAL } AccessHint;
@ -953,14 +972,17 @@ newEntry(jzfile *zip, jzcell *zc, AccessHint accessHint)
ze->comment = NULL;
#ifdef USE_MMAP
cen = (char*) zip->maddr + zc->cenpos - zip->offset;
#else
if (accessHint == ACCESS_RANDOM)
cen = readCENHeader(zip, zc->cenpos, AMPLE_CEN_HEADER_SIZE);
else
cen = sequentialAccessReadCENHeader(zip, zc->cenpos);
if (cen == NULL) goto Catch;
if (zip->usemmap) {
cen = (char*) zip->maddr + zc->cenpos - zip->offset;
} else
#endif
{
if (accessHint == ACCESS_RANDOM)
cen = readCENHeader(zip, zc->cenpos, AMPLE_CEN_HEADER_SIZE);
else
cen = sequentialAccessReadCENHeader(zip, zc->cenpos);
if (cen == NULL) goto Catch;
}
nlen = CENNAM(cen);
elen = CENEXT(cen);
@ -976,7 +998,6 @@ newEntry(jzfile *zip, jzcell *zc, AccessHint accessHint)
if ((ze->name = malloc(nlen + 1)) == NULL) goto Catch;
memcpy(ze->name, cen + CENHDR, nlen);
ze->name[nlen] = '\0';
if (elen > 0) {
char *extra = cen + CENHDR + nlen;
@ -1037,9 +1058,10 @@ newEntry(jzfile *zip, jzcell *zc, AccessHint accessHint)
ze = NULL;
Finally:
#ifndef USE_MMAP
if (cen != NULL && accessHint == ACCESS_RANDOM) free(cen);
#ifdef USE_MMAP
if (!zip->usemmap)
#endif
if (cen != NULL && accessHint == ACCESS_RANDOM) free(cen);
return ze;
}

10
jdk/src/share/native/java/util/zip/zip_util.h
View File

@ -45,9 +45,6 @@
* Header sizes including signatures
*/
#ifdef USE_MMAP
#define SIGSIZ 4
#endif
#define LOCHDR 30
#define EXTHDR 16
#define CENHDR 46
@ -211,9 +208,9 @@ typedef struct jzfile { /* Zip file */
jlong mlen; /* length (in bytes) mmaped */
jlong offset; /* offset of the mmapped region from the
start of the file. */
#else
cencache cencache; /* CEN header cache */
jboolean usemmap; /* if mmap is used. */
#endif
cencache cencache; /* CEN header cache */
ZFILE zfd; /* open file descriptor */
void *lock; /* read lock */
char *comment; /* zip file comment */
@ -259,6 +256,9 @@ ZIP_Get_From_Cache(const char *name, char **pmsg, jlong lastModified);
jzfile *
ZIP_Put_In_Cache(const char *name, ZFILE zfd, char **pmsg, jlong lastModified);
jzfile *
ZIP_Put_In_Cache0(const char *name, ZFILE zfd, char **pmsg, jlong lastModified, jboolean usemmap);
void JNICALL
ZIP_Close(jzfile *zip);