POSIX GNU tar read support

[jopadan]

• supporting tared csm.bin of Chasm: The Rift Remastered at https://store.steampowered.com/app/2061230/Chasm_The_Rift/
• See @Panzerschrek Chasm-Reverse pull request for a working implementation

[icculus]

This can't be merged as-is, as it contains code licensed under the GPL. Sorry.

[sezero]

Here is the working and clean build fix against your latest commit:

diff --git a/src/physfs_archiver_tar.c b/src/physfs_archiver_tar.c
index c0d5f44..41a3920 100644
--- a/src/physfs_archiver_tar.c
+++ b/src/physfs_archiver_tar.c
@@ -14,10 +14,14 @@
 
 static bool TAR_loadEntries(PHYSFS_Io *io, void *arc)
 {
-	union block zero_block = { .buffer = { 0 } };
-	union block current_block = { .buffer = { 0 } };
+	union block zero_block;
+	union block current_block;
 	PHYSFS_uint64 count = 0;
 
+
+	memset(zero_block.buffer, 0, sizeof(zero_block.buffer));
+	memset(current_block.buffer, 0, sizeof(current_block.buffer));
+
 	/* read header block until zero-only terminated block */
 	for(; __PHYSFS_readAll(io, current_block.buffer, BLOCKSIZE); count++)
 	{
@@ -25,8 +29,7 @@ static bool TAR_loadEntries(PHYSFS_Io *io, void *arc)
 			return true;
 
 		/* verify magic */
-		int format = TAR_magic(&current_block);
-		switch(format)
+		switch(TAR_magic(&current_block))
 		{
 			case POSIX_FORMAT:
 				TAR_posix_block(io, arc, &current_block, &count);
@@ -53,14 +56,15 @@ static void *TAR_openArchive(PHYSFS_Io *io, const char *name,
                               int forWriting, int *claimed)
 {
     void *unpkarc = NULL;
+    union block first;
+    enum archive_format format;
 
     assert(io != NULL);  /* shouldn't ever happen. */
 
     BAIL_IF(forWriting, PHYSFS_ERR_READ_ONLY, NULL);
 
-    union block first;
     BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, first.buffer, BLOCKSIZE), NULL);
-    int format = TAR_magic(&first);
+    format = TAR_magic(&first);
     io->seek(io, 0);
     *claimed = format == DEFAULT_FORMAT ? 0 : 1;
 
diff --git a/src/physfs_tar.h b/src/physfs_tar.h
index 30b920a..ec51f0e 100644
--- a/src/physfs_tar.h
+++ b/src/physfs_tar.h
@@ -7,6 +7,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include <ctype.h>
+#include <sys/stat.h>
 #include <fcntl.h>
 #include <time.h>
 
@@ -137,12 +138,12 @@ static bool TAR_encodeOctal(char* data, size_t size, PHYSFS_uint64 i) {
     return true;
 }
 
-static int TAR_magic(union block* block) {
+static enum archive_format TAR_magic(union block* block) {
 	if(strcmp(block->header.magic, OLDGNU_MAGIC) == 0 && strncmp(block->header.version, TVERSION, 2) == 0)
-		return (int)OLDGNU_FORMAT;
+		return OLDGNU_FORMAT;
 	if(strncmp(block->header.magic, TMAGIC, TMAGLEN - 1) == 0)
-		return (int)POSIX_FORMAT;
-	return (int)DEFAULT_FORMAT;
+		return POSIX_FORMAT;
+	return DEFAULT_FORMAT;
 }
 
 static size_t TAR_fileSize(union block* block) {

[sezero]

The mode procedures aren't used: I'm guessing that commenting them out will make windows builds succeed.

[sezero]

The following patch makes a clean-up of the whole thing:

diff --git a/src/physfs_tar.h b/src/physfs_tar.h
index e15bc68..aca7e40 100644
--- a/src/physfs_tar.h
+++ b/src/physfs_tar.h
@@ -1,15 +1,7 @@
 #ifndef _INCLUDE_PHYSFS_TAR_H_
 #define _INCLUDE_PHYSFS_TAR_H_
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
 #include <stdbool.h>
-#include <string.h>
-#include <ctype.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <time.h>
 
 #ifndef PATH_MAX
 #define PATH_MAX 1024
@@ -132,21 +124,15 @@ static PHYSFS_uint64 TAR_decodeOctal(char* data, size_t size) {
     return sum;
 }
 
-static bool TAR_encodeOctal(char* data, size_t size, PHYSFS_uint64 i) {
-    if(	snprintf(data, size, "%llo", i) < 0 )
-    	return false;
-    return true;
-}
-
 static int TAR_magic(union block* block) {
 	if(strcmp(block->header.magic, OLDGNU_MAGIC) == 0 && strncmp(block->header.version, TVERSION, 2) == 0)
-		return (int)OLDGNU_FORMAT;
+		return OLDGNU_FORMAT;
 	if(strncmp(block->header.magic, TMAGIC, TMAGLEN - 1) == 0)
-		return (int)POSIX_FORMAT;
-	return (int)DEFAULT_FORMAT;
+		return POSIX_FORMAT;
+	return DEFAULT_FORMAT;
 }
 
-static size_t TAR_fileSize(union block* block) {
+static PHYSFS_uint64 TAR_fileSize(union block* block) {
 	return TAR_decodeOctal(block->header.size, sizeof(block->header.size));
 }
 
@@ -169,12 +155,12 @@ static bool TAR_checksum(union block* block) {
 	return (reference_chksum == unsigned_sum || reference_chksum == signed_sum);
 }
 
-time_t TAR_time(union block* block)
+static PHYSFS_uint64 TAR_time(union block* block)
 {
 	return TAR_decodeOctal(block->header.mtime, 12);
 }
 
-bool TAR_posix_block(PHYSFS_Io* io, void* arc, union block* block, PHYSFS_uint64* count)
+static bool TAR_posix_block(PHYSFS_Io* io, void* arc, union block* block, PHYSFS_uint64* count)
 {
 	static bool long_name = false;
 	const PHYSFS_Allocator* allocator = PHYSFS_getAllocator();

long_name having persistent storage in TAR_posix_block is a problem.
Haven't tried to follow the logic much, but if you truly want following
it then I suggest passing it as a reference from its caller, e.g. like
below: (compile-tested only !!)

diff --git a/src/physfs_archiver_tar.c b/src/physfs_archiver_tar.c
index e9ad4f0..03dcab6 100644
--- a/src/physfs_archiver_tar.c
+++ b/src/physfs_archiver_tar.c
@@ -17,6 +17,7 @@ static bool TAR_loadEntries(PHYSFS_Io *io, void *arc)
 	union block zero_block;
 	union block current_block;
 	PHYSFS_uint64 count = 0;
+	bool long_name = false;
 
 	memset(zero_block.buffer, 0, sizeof(BLOCKSIZE));
 	memset(current_block.buffer, 0, sizeof(BLOCKSIZE));
@@ -31,7 +32,7 @@ static bool TAR_loadEntries(PHYSFS_Io *io, void *arc)
 		switch(TAR_magic(&current_block))
 		{
 			case POSIX_FORMAT:
-				TAR_posix_block(io, arc, &current_block, &count);
+				TAR_posix_block(io, arc, &current_block, &count, &long_name);
 				break;
 			case OLDGNU_FORMAT:
 				break;
diff --git a/src/physfs_tar.h b/src/physfs_tar.h
index aca7e40..63f2974 100644
--- a/src/physfs_tar.h
+++ b/src/physfs_tar.h
@@ -160,9 +160,8 @@ static PHYSFS_uint64 TAR_time(union block* block)
 	return TAR_decodeOctal(block->header.mtime, 12);
 }
 
-static bool TAR_posix_block(PHYSFS_Io* io, void* arc, union block* block, PHYSFS_uint64* count)
+static bool TAR_posix_block(PHYSFS_Io* io, void* arc, union block* block, PHYSFS_uint64* count, bool *long_name)
 {
-	static bool long_name = false;
 	const PHYSFS_Allocator* allocator = PHYSFS_getAllocator();
         char name[PATH_MAX] = { 0 };
 	PHYSFS_sint64 time  = 0;
@@ -190,10 +189,10 @@ static bool TAR_posix_block(PHYSFS_Io* io, void* arc, union block* block, PHYSFS
 	/* add file type entry */
 	if (block->header.typeflag == REGTYPE || block->header.typeflag == 0) {
 		/* support long file names */
-		if(long_name) {
+		if(*long_name) {
 			strcpy(&name[0], block->header.name);
 			BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, block->buffer, BLOCKSIZE), 0);
-			long_name = false;
+			*long_name = false;
 			(*count)++;
 		}
 		size = TAR_fileSize(block);
@@ -214,7 +213,7 @@ static bool TAR_posix_block(PHYSFS_Io* io, void* arc, union block* block, PHYSFS
 	/* long name mode */
 	else if(block->header.typeflag == GNUTYPE_LONGNAME)
 	{
-		long_name = true;
+		*long_name = true;
 	}
 	else
 	{

The rest is up to @icculus.

[jopadan]

@sezero: Thanks for the changes and hints I've integrated them into the pull request.

[sezero]

@sezero: Thanks for the changes and hints I've integrated them into the pull request.

Thanks: all my change requests are addressed. It's in @icculus hands now.

[jopadan]

This can't be merged as-is, as it contains code licensed under the GPL. Sorry.

@icculus
I've modified the code not to contain the original code licensed under the GPL now.
zlib license seems to be compatible with GPL but not the other way around.