Java example source code file (parse_manifest.c)
The parse_manifest.c Java example source code
/*
* Copyright (c) 2003, 2013, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "jli_util.h"
#include <zlib.h>
#include "manifest_info.h"
static char *manifest;
static const char *manifest_name = "META-INF/MANIFEST.MF";
/*
* Inflate the manifest file (or any file for that matter).
*
* fd: File descriptor of the jar file.
* entry: Contains the information necessary to perform the inflation
* (the compressed and uncompressed sizes and the offset in
* the file where the compressed data is located).
* size_out: Returns the size of the inflated file.
*
* Upon success, it returns a pointer to a NUL-terminated malloc'd buffer
* containing the inflated manifest file. When the caller is done with it,
* this buffer should be released by a call to free(). Upon failure,
* returns NULL.
*/
static char *
inflate_file(int fd, zentry *entry, int *size_out)
{
char *in;
char *out;
z_stream zs;
if (entry->csize == (size_t) -1 || entry->isize == (size_t) -1 )
return (NULL);
if (JLI_Lseek(fd, entry->offset, SEEK_SET) < (jlong)0)
return (NULL);
if ((in = malloc(entry->csize + 1)) == NULL)
return (NULL);
if ((size_t)(read(fd, in, (unsigned int)entry->csize)) != entry->csize) {
free(in);
return (NULL);
}
if (entry->how == STORED) {
*(char *)((size_t)in + entry->csize) = '\0';
if (size_out) {
*size_out = (int)entry->csize;
}
return (in);
} else if (entry->how == DEFLATED) {
zs.zalloc = (alloc_func)Z_NULL;
zs.zfree = (free_func)Z_NULL;
zs.opaque = (voidpf)Z_NULL;
zs.next_in = (Byte*)in;
zs.avail_in = (uInt)entry->csize;
if (inflateInit2(&zs, -MAX_WBITS) < 0) {
free(in);
return (NULL);
}
if ((out = malloc(entry->isize + 1)) == NULL) {
free(in);
return (NULL);
}
zs.next_out = (Byte*)out;
zs.avail_out = (uInt)entry->isize;
if (inflate(&zs, Z_PARTIAL_FLUSH) < 0) {
free(in);
free(out);
return (NULL);
}
*(char *)((size_t)out + entry->isize) = '\0';
free(in);
if (inflateEnd(&zs) < 0) {
free(out);
return (NULL);
}
if (size_out) {
*size_out = (int)entry->isize;
}
return (out);
}
free(in);
return (NULL);
}
static jboolean zip64_present = JNI_FALSE;
/*
* Checks to see if we have ZIP64 archive, and save
* the check for later use
*/
static int
haveZIP64(Byte *p) {
jlong cenlen, cenoff, centot;
cenlen = ENDSIZ(p);
cenoff = ENDOFF(p);
centot = ENDTOT(p);
zip64_present = (cenlen == ZIP64_MAGICVAL ||
cenoff == ZIP64_MAGICVAL ||
centot == ZIP64_MAGICCOUNT);
return zip64_present;
}
static jlong
find_end64(int fd, Byte *ep, jlong pos)
{
jlong end64pos;
jlong bytes;
if ((end64pos = JLI_Lseek(fd, pos - ZIP64_LOCHDR, SEEK_SET)) < (jlong)0)
return -1;
if ((bytes = read(fd, ep, ZIP64_LOCHDR)) < 0)
return -1;
if (GETSIG(ep) == ZIP64_LOCSIG)
return end64pos;
return -1;
}
/*
* A very little used routine to handle the case that zip file has
* a comment at the end. Believe it or not, the only way to find the
* END record is to walk backwards, byte by bloody byte looking for
* the END record signature.
*
* fd: File descriptor of the jar file.
* eb: Pointer to a buffer to receive a copy of the END header.
*
* Returns the offset of the END record in the file on success,
* -1 on failure.
*/
static jlong
find_end(int fd, Byte *eb)
{
jlong len;
jlong pos;
jlong flen;
int bytes;
Byte *cp;
Byte *endpos;
Byte *buffer;
/*
* 99.44% (or more) of the time, there will be no comment at the
* end of the zip file. Try reading just enough to read the END
* record from the end of the file, at this time we should also
* check to see if we have a ZIP64 archive.
*/
if ((pos = JLI_Lseek(fd, -ENDHDR, SEEK_END)) < (jlong)0)
return (-1);
if ((bytes = read(fd, eb, ENDHDR)) < 0)
return (-1);
if (GETSIG(eb) == ENDSIG) {
return haveZIP64(eb) ? find_end64(fd, eb, pos) : pos;
}
/*
* Shucky-Darn,... There is a comment at the end of the zip file.
*
* Allocate and fill a buffer with enough of the zip file
* to meet the specification for a maximal comment length.
*/
if ((flen = JLI_Lseek(fd, 0, SEEK_END)) < (jlong)0)
return (-1);
len = (flen < END_MAXLEN) ? flen : END_MAXLEN;
if (JLI_Lseek(fd, -len, SEEK_END) < (jlong)0)
return (-1);
if ((buffer = malloc(END_MAXLEN)) == NULL)
return (-1);
if ((bytes = read(fd, buffer, len)) < 0) {
free(buffer);
return (-1);
}
/*
* Search backwards from the end of file stopping when the END header
* signature is found. (The first condition of the "if" is just a
* fast fail, because the GETSIG macro isn't always cheap. The
* final condition protects against false positives.)
*/
endpos = &buffer[bytes];
for (cp = &buffer[bytes - ENDHDR]; cp >= &buffer[0]; cp--)
if ((*cp == (ENDSIG & 0xFF)) && (GETSIG(cp) == ENDSIG) &&
(cp + ENDHDR + ENDCOM(cp) == endpos)) {
(void) memcpy(eb, cp, ENDHDR);
free(buffer);
pos = flen - (endpos - cp);
return haveZIP64(eb) ? find_end64(fd, eb, pos) : pos;
}
free(buffer);
return (-1);
}
#define BUFSIZE (3 * 65536 + CENHDR + SIGSIZ)
#define MINREAD 1024
/*
* Computes and positions at the start of the CEN header, ie. the central
* directory, this will also return the offset if there is a zip file comment
* at the end of the archive, for most cases this would be 0.
*/
static jlong
compute_cen(int fd, Byte *bp)
{
int bytes;
Byte *p;
jlong base_offset;
jlong offset;
char buffer[MINREAD];
p = buffer;
/*
* Read the END Header, which is the starting point for ZIP files.
* (Clearly designed to make writing a zip file easier than reading
* one. Now isn't that precious...)
*/
if ((base_offset = find_end(fd, bp)) == -1) {
return (-1);
}
p = bp;
/*
* There is a historical, but undocumented, ability to allow for
* additional "stuff" to be prepended to the zip/jar file. It seems
* that this has been used to prepend an actual java launcher
* executable to the jar on Windows. Although this is just another
* form of statically linking a small piece of the JVM to the
* application, we choose to continue to support it. Note that no
* guarantees have been made (or should be made) to the customer that
* this will continue to work.
*
* Therefore, calculate the base offset of the zip file (within the
* expanded file) by assuming that the central directory is followed
* immediately by the end record.
*/
if (zip64_present) {
if ((offset = ZIP64_LOCOFF(p)) < (jlong)0) {
return -1;
}
if (JLI_Lseek(fd, offset, SEEK_SET) < (jlong) 0) {
return (-1);
}
if ((bytes = read(fd, buffer, MINREAD)) < 0) {
return (-1);
}
if (GETSIG(buffer) != ZIP64_ENDSIG) {
return -1;
}
if ((offset = ZIP64_ENDOFF(buffer)) < (jlong)0) {
return -1;
}
if (JLI_Lseek(fd, offset, SEEK_SET) < (jlong)0) {
return (-1);
}
p = buffer;
base_offset = base_offset - ZIP64_ENDSIZ(p) - ZIP64_ENDOFF(p) - ZIP64_ENDHDR;
} else {
base_offset = base_offset - ENDSIZ(p) - ENDOFF(p);
/*
* The END Header indicates the start of the Central Directory
* Headers. Remember that the desired Central Directory Header (CEN)
* will almost always be the second one and the first one is a small
* directory entry ("META-INF/"). Keep the code optimized for
* that case.
*
* Seek to the beginning of the Central Directory.
*/
if (JLI_Lseek(fd, base_offset + ENDOFF(p), SEEK_SET) < (jlong) 0) {
return (-1);
}
}
return base_offset;
}
/*
* Locate the manifest file with the zip/jar file.
*
* fd: File descriptor of the jar file.
* entry: To be populated with the information necessary to perform
* the inflation (the compressed and uncompressed sizes and
* the offset in the file where the compressed data is located).
*
* Returns zero upon success. Returns a negative value upon failure.
*
* The buffer for reading the Central Directory if the zip/jar file needs
* to be large enough to accommodate the largest possible single record
* and the signature of the next record which is:
*
* 3*2**16 + CENHDR + SIGSIZ
*
* Each of the three variable sized fields (name, comment and extension)
* has a maximum possible size of 64k.
*
* Typically, only a small bit of this buffer is used with bytes shuffled
* down to the beginning of the buffer. It is one thing to allocate such
* a large buffer and another thing to actually start faulting it in.
*
* In most cases, all that needs to be read are the first two entries in
* a typical jar file (META-INF and META-INF/MANIFEST.MF). Keep this factoid
* in mind when optimizing this code.
*/
static int
find_file(int fd, zentry *entry, const char *file_name)
{
int bytes;
int res;
int entry_size;
int read_size;
jlong base_offset;
Byte *p;
Byte *bp;
Byte *buffer;
Byte locbuf[LOCHDR];
if ((buffer = (Byte*)malloc(BUFSIZE)) == NULL) {
return(-1);
}
bp = buffer;
base_offset = compute_cen(fd, bp);
if (base_offset == -1) {
free(buffer);
return -1;
}
if ((bytes = read(fd, bp, MINREAD)) < 0) {
free(buffer);
return (-1);
}
p = bp;
/*
* Loop through the Central Directory Headers. Note that a valid zip/jar
* must have an ENDHDR (with ENDSIG) after the Central Directory.
*/
while (GETSIG(p) == CENSIG) {
/*
* If a complete header isn't in the buffer, shift the contents
* of the buffer down and refill the buffer. Note that the check
* for "bytes < CENHDR" must be made before the test for the entire
* size of the header, because if bytes is less than CENHDR, the
* actual size of the header can't be determined. The addition of
* SIGSIZ guarantees that the next signature is also in the buffer
* for proper loop termination.
*/
if (bytes < CENHDR) {
p = memmove(bp, p, bytes);
if ((res = read(fd, bp + bytes, MINREAD)) <= 0) {
free(buffer);
return (-1);
}
bytes += res;
}
entry_size = CENHDR + CENNAM(p) + CENEXT(p) + CENCOM(p);
if (bytes < entry_size + SIGSIZ) {
if (p != bp)
p = memmove(bp, p, bytes);
read_size = entry_size - bytes + SIGSIZ;
read_size = (read_size < MINREAD) ? MINREAD : read_size;
if ((res = read(fd, bp + bytes, read_size)) <= 0) {
free(buffer);
return (-1);
}
bytes += res;
}
/*
* Check if the name is the droid we are looking for; the jar file
* manifest. If so, build the entry record from the data found in
* the header located and return success.
*/
if ((size_t)CENNAM(p) == JLI_StrLen(file_name) &&
memcmp((p + CENHDR), file_name, JLI_StrLen(file_name)) == 0) {
if (JLI_Lseek(fd, base_offset + CENOFF(p), SEEK_SET) < (jlong)0) {
free(buffer);
return (-1);
}
if (read(fd, locbuf, LOCHDR) < 0) {
free(buffer);
return (-1);
}
if (GETSIG(locbuf) != LOCSIG) {
free(buffer);
return (-1);
}
entry->isize = CENLEN(p);
entry->csize = CENSIZ(p);
entry->offset = base_offset + CENOFF(p) + LOCHDR +
LOCNAM(locbuf) + LOCEXT(locbuf);
entry->how = CENHOW(p);
free(buffer);
return (0);
}
/*
* Point to the next entry and decrement the count of valid remaining
* bytes.
*/
bytes -= entry_size;
p += entry_size;
}
free(buffer);
return (-1); /* Fell off the end the loop without a Manifest */
}
/*
* Parse a Manifest file header entry into a distinct "name" and "value".
* Continuation lines are joined into a single "value". The documented
* syntax for a header entry is:
*
* header: name ":" value
*
* name: alphanum *headerchar
*
* value: SPACE *otherchar newline *continuation
*
* continuation: SPACE *otherchar newline
*
* newline: CR LF | LF | CR (not followed by LF)
*
* alphanum: {"A"-"Z"} | {"a"-"z"} | {"0"-"9"}
*
* headerchar: alphanum | "-" | "_"
*
* otherchar: any UTF-8 character except NUL, CR and LF
*
* Note that a manifest file may be composed of multiple sections,
* each of which may contain multiple headers.
*
* section: *header +newline
*
* nonempty-section: +header +newline
*
* (Note that the point of "nonempty-section" is unclear, because it isn't
* referenced elsewhere in the full specification for the Manifest file.)
*
* Arguments:
* lp pointer to a character pointer which points to the start
* of a valid header.
* name pointer to a character pointer which will be set to point
* to the name portion of the header (nul terminated).
* value pointer to a character pointer which will be set to point
* to the value portion of the header (nul terminated).
*
* Returns:
* 1 Successful parsing of an NV pair. lp is updated to point to the
* next character after the terminating newline in the string
* representing the Manifest file. name and value are updated to
* point to the strings parsed.
* 0 A valid end of section indicator was encountered. lp, name, and
* value are not modified.
* -1 lp does not point to a valid header. Upon return, the values of
* lp, name, and value are undefined.
*/
static int
parse_nv_pair(char **lp, char **name, char **value)
{
char *nl;
char *cp;
/*
* End of the section - return 0. The end of section condition is
* indicated by either encountering a blank line or the end of the
* Manifest "string" (EOF).
*/
if (**lp == '\0' || **lp == '\n' || **lp == '\r')
return (0);
/*
* Getting to here, indicates that *lp points to an "otherchar".
* Turn the "header" into a string on its own.
*/
nl = JLI_StrPBrk(*lp, "\n\r");
if (nl == NULL) {
nl = JLI_StrChr(*lp, (int)'\0');
} else {
cp = nl; /* For merging continuation lines */
if (*nl == '\r' && *(nl+1) == '\n')
*nl++ = '\0';
*nl++ = '\0';
/*
* Process any "continuation" line(s), by making them part of the
* "header" line. Yes, I know that we are "undoing" the NULs we
* just placed here, but continuation lines are the fairly rare
* case, so we shouldn't unnecessarily complicate the code above.
*
* Note that an entire continuation line is processed each iteration
* through the outer while loop.
*/
while (*nl == ' ') {
nl++; /* First character to be moved */
while (*nl != '\n' && *nl != '\r' && *nl != '\0')
*cp++ = *nl++; /* Shift string */
if (*nl == '\0')
return (-1); /* Error: newline required */
*cp = '\0';
if (*nl == '\r' && *(nl+1) == '\n')
*nl++ = '\0';
*nl++ = '\0';
}
}
/*
* Separate the name from the value;
*/
cp = JLI_StrChr(*lp, (int)':');
if (cp == NULL)
return (-1);
*cp++ = '\0'; /* The colon terminates the name */
if (*cp != ' ')
return (-1);
*cp++ = '\0'; /* Eat the required space */
*name = *lp;
*value = cp;
*lp = nl;
return (1);
}
/*
* Read the manifest from the specified jar file and fill in the manifest_info
* structure with the information found within.
*
* Error returns are as follows:
* 0 Success
* -1 Unable to open jarfile
* -2 Error accessing the manifest from within the jarfile (most likely
* a manifest is not present, or this isn't a valid zip/jar file).
*/
int
JLI_ParseManifest(char *jarfile, manifest_info *info)
{
int fd;
zentry entry;
char *lp;
char *name;
char *value;
int rc;
char *splashscreen_name = NULL;
if ((fd = open(jarfile, O_RDONLY
#ifdef O_LARGEFILE
| O_LARGEFILE /* large file mode */
#endif
#ifdef O_BINARY
| O_BINARY /* use binary mode on windows */
#endif
)) == -1) {
return (-1);
}
info->manifest_version = NULL;
info->main_class = NULL;
info->jre_version = NULL;
info->jre_restrict_search = 0;
info->splashscreen_image_file_name = NULL;
if (rc = find_file(fd, &entry, manifest_name) != 0) {
close(fd);
return (-2);
}
manifest = inflate_file(fd, &entry, NULL);
if (manifest == NULL) {
close(fd);
return (-2);
}
lp = manifest;
while ((rc = parse_nv_pair(&lp, &name, &value)) > 0) {
if (JLI_StrCaseCmp(name, "Manifest-Version") == 0)
info->manifest_version = value;
else if (JLI_StrCaseCmp(name, "Main-Class") == 0)
info->main_class = value;
else if (JLI_StrCaseCmp(name, "JRE-Version") == 0)
info->jre_version = value;
else if (JLI_StrCaseCmp(name, "JRE-Restrict-Search") == 0) {
if (JLI_StrCaseCmp(value, "true") == 0)
info->jre_restrict_search = 1;
} else if (JLI_StrCaseCmp(name, "Splashscreen-Image") == 0) {
info->splashscreen_image_file_name = value;
}
}
close(fd);
if (rc == 0)
return (0);
else
return (-2);
}
/*
* Opens the jar file and unpacks the specified file from its contents.
* Returns NULL on failure.
*/
void *
JLI_JarUnpackFile(const char *jarfile, const char *filename, int *size) {
int fd;
zentry entry;
void *data = NULL;
if ((fd = open(jarfile, O_RDONLY
#ifdef O_LARGEFILE
| O_LARGEFILE /* large file mode */
#endif
#ifdef O_BINARY
| O_BINARY /* use binary mode on windows */
#endif
)) == -1) {
return NULL;
}
if (find_file(fd, &entry, filename) == 0) {
data = inflate_file(fd, &entry, size);
}
close(fd);
return (data);
}
/*
* Specialized "free" function.
*/
void
JLI_FreeManifest()
{
if (manifest)
free(manifest);
}
/*
* Iterate over the manifest of the specified jar file and invoke the provided
* closure function for each attribute encountered.
*
* Error returns are as follows:
* 0 Success
* -1 Unable to open jarfile
* -2 Error accessing the manifest from within the jarfile (most likely
* this means a manifest is not present, or it isn't a valid zip/jar file).
*/
int
JLI_ManifestIterate(const char *jarfile, attribute_closure ac, void *user_data)
{
int fd;
zentry entry;
char *mp; /* manifest pointer */
char *lp; /* pointer into manifest, updated during iteration */
char *name;
char *value;
int rc;
if ((fd = open(jarfile, O_RDONLY
#ifdef O_LARGEFILE
| O_LARGEFILE /* large file mode */
#endif
#ifdef O_BINARY
| O_BINARY /* use binary mode on windows */
#endif
)) == -1) {
return (-1);
}
if (rc = find_file(fd, &entry, manifest_name) != 0) {
close(fd);
return (-2);
}
mp = inflate_file(fd, &entry, NULL);
if (mp == NULL) {
close(fd);
return (-2);
}
lp = mp;
while ((rc = parse_nv_pair(&lp, &name, &value)) > 0) {
(*ac)(name, value, user_data);
}
free(mp);
close(fd);
return (rc == 0) ? 0 : -2;
}
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