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.