int handle_datagram(datagram *dptr, FILE *fp, uint32_t *skips)
{
int status = STATUS_CONTINUE;
// Get the length of the data portion in bytes (not including the header)
uint8_t data_length = dptr->length - sizeof(datagram);
// Get the datagram type
uint8_t type = dptr->type;
if (*skips > 0 || dptr->data.skip_bit) {
// Handle skipping N datagrams and the skip bit
if (*skips > 0) {
--(*skips);
}
return skip_datagram(fp, data_length);
}
// Make sure the version is valid
if (dptr->version < 1 || dptr->version > 3) {
printf("Invalid version: %u\n", dptr->version);
return status;
}
// Normally, we only run things once
int run_count = 1;
// When the dupe bit is set, run things twice
if (dptr->version == 2 && dptr->data.version2.dupe_bit) {
run_count = 2;
}
if (dptr->version == 2 || dptr->version == 3) {
// Skip the datagram if the checksum is invalid (ignoring the length)
if (!valid_checksum(dptr)) {
while (run_count--) {
printf("Checksum is invalid!!!\n");
}
return status;
}
}
if (dptr->length < sizeof(datagram)) {
// Make sure the length is valid
while (run_count--) {
printf("Length is invalid: %u\n", dptr->length);
}
status = STATUS_FAIL;
}
else if ((type >= 0 && type <= 3) || type == 7) {
// Handle datagram containing data
// Allocate memory to read the data
void *data = malloc(data_length);
// Read the data from the file into the buffer
size_t bytes_read = fread(data, 1, data_length, fp);
if (bytes_read == data_length) {
// Print the data read as the correct type
while (run_count--) {
print_data(type, data, data_length);
}
}
else {
while (run_count--) {
printf("Read %lu/%u bytes of the datagram.\n", bytes_read, data_length);
}
status = STATUS_FAIL;
}
// Free the memory allocated for the data
free(data);
}
else if (type == CONTROL_SKIP) {
// Handle datagram containing SKIP instruction
// Read the number of datagrams to skip from the file (store this number in skips)
size_t bytes_read = fread(skips, 1, sizeof(*skips), fp);
// Modify the skip value according to the run count.
// (This doubles the skips if the dupe bit is set.)
(*skips) *= run_count;
// If the number could not be read, then fail
if (bytes_read != sizeof(*skips)) {
status = STATUS_FAIL;
}
}
else if (type == CONTROL_BURN) {
// Handle datagram containing BURN instruction
while (run_count--) {
status = handle_burn();
}
}
else if (type == CONTROL_STOP) {
// Handle datagram containing STOP instruction
// Stop reading the file
status = STATUS_STOP;
}
else if (type == TYPE_JUNK) {
// Handle datagram containing junk data
// Skip junk data
status = skip_datagram(fp, data_length);
}
else {
// Handle datagram with unrecognized type value
printf("Unknown datagram type: %u\n", type);
status = STATUS_FAIL;
}
return status;
}
/* Tar file extraction
* gzFile in, handle of input tarball opened with gzopen
* int cm, compressionMethod
* int junkPaths, nonzero indicates to ignore stored path (don't create directories)
* enum KeepMode keep, indicates to perform if file exists
* int iCnt, char *iList[], argv style list of files to extract, {0,NULL} for all
* int xCnt, char *xList[], argv style list of files NOT to extract, {0,NULL} for none
* int failOnHardLinks, if nonzero then will treat failure to create a hard link same as
* failure to create a regular file, 0 prints a warning if fails - note that hardlinks
* will always fail on Windows prior to NT 5 (Win 2000) or later and non NTFS file systems.
*
* returns 0 (or positive value) on success
* returns negative value on error, where
* -1 means error reading from tarball
* -2 means error extracting file from tarball
* -3 means error creating hard link
*/
int tgz_extract(gzFile in, int cm, int junkPaths, enum KeepMode keep, int iCnt, TCHAR *iList[], int xCnt, TCHAR *xList[], int failOnHardLinks)
{
int getheader = 1; /* assume initial input has a tar header */
HANDLE outfile = INVALID_HANDLE_VALUE;
union tar_buffer buffer;
unsigned long remaining;
TCHAR fname[BLOCKSIZE]; /* must be >= BLOCKSIZE bytes */
time_t tartime;
/* do any prep work for extracting from compressed TAR file */
if (cm_init(in, cm))
{
PrintMessage(_T("tgz_extract: unable to initialize decompression method."));
cm_cleanup(cm);
return -1;
}
while (1)
{
if (readBlock(cm, &buffer) < 0) return -1;
/*
* If we have to get a tar header
*/
if (getheader >= 1)
{
/*
* if we met the end of the tar
* or the end-of-tar block,
* we are done
*/
if (/* (len == 0) || */ (buffer.header.name[0]== 0)) break;
/* compute and check header checksum, support signed or unsigned */
if (!valid_checksum(&(buffer.header)))
{
PrintMessage(_T("tgz_extract: bad header checksum"));
cm_cleanup(cm);
return -1;
}
/* store time, so we can set the timestamp on files */
tartime = (time_t)getoct(buffer.header.mtime,12);
/* copy over filename chunk from header, avoiding overruns */
if (getheader == 1) /* use normal (short or posix long) filename from header */
{
/* NOTE: prepends any prefix, including separator, and ensures terminated */
memset(fname, 0, sizeof(fname));
getFullName(&buffer, fname);
}
else /* use (GNU) long filename that preceeded this header */
{
#if 0
/* if (strncmp(fname,buffer.header.name,SHORTNAMESIZE-1) != 0) */
char fs[SHORTNAMESIZE]; /* force strings to same max len, then compare */
lstrcpyn(fs, fname, SHORTNAMESIZE);
fs[SHORTNAMESIZE-1] = '\0';
buffer.header.name[SHORTNAMESIZE-1] = '\0';
if (lstrcmp(fs, buffer.header.name) != 0)
{
PrintMessage(_T("tgz_extract: mismatched long filename"));
cm_cleanup(cm);
return -1;
}
#else
PrintMessage(_T("tgz_extract: using GNU long filename [%s]"), fname);
#endif
}
/* LogMessage("buffer.header.name is:"); LogMessage(fname); */
switch (buffer.header.typeflag)
{
case DIRTYPE:
dirEntry:
if (!junkPaths)
{
safetyStrip(fname);
makedir(fname);
}
break;
case LNKTYPE: /* hard link */
case CONTTYPE: /* contiguous file, for compatibility treat as normal */
case REGTYPE:
case AREGTYPE:
/* Note: a file ending with a / may actually be a BSD tar directory entry */
if (fname[strlen(fname)-1] == '/')
goto dirEntry;
remaining = getoct(buffer.header.size,12);
if ( /* add (remaining > 0) && to ignore 0 zero byte files */
( (iList == NULL) || (matchname(fname, iCnt, iList, junkPaths)) ) &&
(!matchname(fname, xCnt, xList, junkPaths))
)
{
if (!junkPaths) /* if we want to use paths as stored */
{
/* try creating directory */
TCHAR *p = tstrrchr(fname, '/');
if (p != NULL)
{
*p = '\0';
makedir(fname);
*p = '/';
}
}
else
{
/* try ignoring directory */
TCHAR *p = tstrrchr(fname, '/');
if (p != NULL)
{
/* be sure terminating '\0' is copied and */
/* use ansi memcpy equivalent that handles overlapping regions */
MoveMemory(fname, p+1, (strlen(p+1) + 1) * sizeof(TCHAR) );
}
}
if (*fname) /* if after stripping path a fname still exists */
{
/* Attempt to open the output file and report action taken to user */
const TCHAR szERRMsg[] = _T("Error: Could not create file "),
szSUCMsg[] = _T("Writing "),
szSKPMsg[] = _T("Skipping ");
const TCHAR * szMsg = szSUCMsg;
safetyStrip(fname);
if (buffer.header.typeflag == LNKTYPE)
{
outfile = INVALID_HANDLE_VALUE;
/* create a hardlink if possible, else produce just a warning unless failOnHardLinks is true */
if (!MakeHardLink(fname, buffer.header.linkname))
{
PrintMessage(_T("Warning: unable to create hard link %s [%d]"), fname, GetLastError());
if (failOnHardLinks)
{
cm_cleanup(cm);
return -3;
}
}
else
{
outfile = CreateFile(fname,GENERIC_WRITE,FILE_SHARE_READ,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
goto setTimeAndCloseFile;
}
} else
{
/* Open the file for writing mode, creating if doesn't exist and truncating if exists and overwrite mode */
outfile = CreateFile(fname,GENERIC_WRITE,FILE_SHARE_READ,NULL,(keep==OVERWRITE)?CREATE_ALWAYS:CREATE_NEW,FILE_ATTRIBUTE_NORMAL,NULL);
/* failed to open file, either valid error (like open) or it already exists and in a keep mode */
if (outfile == INVALID_HANDLE_VALUE)
{
/* if skip existing or only update existing and failed to open becauses exists */
if ((keep!=OVERWRITE) && (GetLastError()==ERROR_FILE_EXISTS))
{
/* assume skipping initially (mode==SKIP or ==UPDATE with existing file newer) */
szMsg = szSKPMsg; /* and update output message accordingly */
/* if in update mode, check filetimes and reopen in overwrite mode */
if (keep == UPDATE)
{
FILETIME ftm_a;
HANDLE h;
WIN32_FIND_DATA ffData;
cnv_tar2win_time(tartime, &ftm_a); /* archive file time */
h = FindFirstFile(fname, &ffData); /* existing file time */
if (h!=INVALID_HANDLE_VALUE)
FindClose(h); /* cleanup search handle */
else
goto ERR_OPENING;
/* compare date+times, is one in tarball newer? */
if (*((LONGLONG *)&ftm_a) > *((LONGLONG *)&(ffData.ftLastWriteTime)))
{
outfile = CreateFile(fname,GENERIC_WRITE,FILE_SHARE_READ,NULL,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);
if (outfile == INVALID_HANDLE_VALUE) goto ERR_OPENING;
szMsg = szSUCMsg;
}
}
}
else /* in overwrite mode or failed for some other error than exists */
{
ERR_OPENING:
PrintMessage(_T("%s%s [%d]"), szERRMsg, fname, GetLastError());
cm_cleanup(cm);
return -2;
}
}
/* Inform user of current extraction action (writing, skipping file XYZ) */
PrintMessage(_T("%s%s"), szMsg, fname);
}
}
}
else
outfile = INVALID_HANDLE_VALUE;
/*
* could have no contents, in which case we close the file and set the times
*/
if (remaining > 0)
getheader = 0;
else
{
setTimeAndCloseFile:
getheader = 1;
if (outfile != INVALID_HANDLE_VALUE)
{
FILETIME ftm;
cnv_tar2win_time(tartime, &ftm);
SetFileTime(outfile,&ftm,NULL,&ftm);
CloseHandle(outfile);
outfile = INVALID_HANDLE_VALUE;
}
}
break;
case GNUTYPE_LONGLINK:
case GNUTYPE_LONGNAME:
{
remaining = getoct(buffer.header.size,12);
if (readBlock(cm, fname) < 0) return -1;
fname[BLOCKSIZE-1] = '\0';
if ((remaining >= BLOCKSIZE) || ((unsigned)strlen(fname) > remaining))
{
PrintMessage(_T("tgz_extract: invalid long name"));
cm_cleanup(cm);
return -1;
}
getheader = 2;
break;
}
default:
/*
if (action == TGZ_LIST)
printf(" %s <---> %s\n",strtime(&tartime),fname);
*/
break;
}
}
else /* (getheader == 0) */
{
unsigned int bytes = (remaining > BLOCKSIZE) ? BLOCKSIZE : remaining;
unsigned long bwritten;
if (outfile != INVALID_HANDLE_VALUE)
{
WriteFile(outfile,buffer.buffer,bytes,&bwritten,NULL);
if (bwritten != bytes)
{
PrintMessage(_T("Error: write failed for %s"), fname);
CloseHandle(outfile);
DeleteFile(fname);
cm_cleanup(cm);
return -2;
}
}
remaining -= bytes;
if (remaining == 0) goto setTimeAndCloseFile;
}
} /* while(1) */
cm_cleanup(cm);
return 0;
}
