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= Overview =
=Overview=
'''S'''igned '''P'''PU '''R'''elocatable E'''x'''ecutable (SPRX)


'''P'''laystation '''R'''elocatable E'''x'''ecutable (PRX)
=Structure=
First LOAD segment p_paddr points to module info.
==Module Info==
{| class="wikitable"
! Offset
! Type
! Description
|-
| +0
| short
| Module attributes
|-
| +2
| char[2]
| Module version
|-
| +4
| char[28]
| Module name
|-
| +32
| long
| TOC address
|-
| +36
| long
| Pointer to the start of exports section
|-
| +40
| long
| Pointer to end of exports section
|-
| +44
| long
| Points to the start of imports section
|-
| +48
| long
| Points to the end of imports section
|}


= PRX2 =
===Exports===
{| class="wikitable"
! Offset
! Type
! Description
|-
| +0
| char[2]
| Structure size (0x1C 32-bit or 0x28 64-bit), padding
|-
| +2
| short
| Version
|-
| +4
| short
| Attributes
|-
| +6
| short
| Number of functions
|-
| +8
| short
| Number of variables
|-
| +10
| short
| Number of thread local storage variables
|-
| +12
| char
| Hash info
|-
| +13
| char
| Thread local storage hash info
|-
| +14
| char[2]
| Reserved
|-
| +16
| long
| Pointer to exported library name
|-
| +20
| long
| Pointer to function NID table
|-
| +24
| long
| Pointer to function stub table
|}


PRX2 is only present on PSVita. PSP and PS3 use PRX version 1.
===Imports===
{| class="wikitable"
! Offset
! Type
! Description
|-
| +0
| char
| Structure size (0x2C)
|-
| +1
| char
| Unused
|-
| +2
| short
| Version
|-
| +4
| short
| Attributes. AUTO_EXPORT=0x0001, WEAK_EXPORT=0x0002, NOLINK_EXPORT=0x0004, WEAK_IMPORT=0x0008, 0x2000 seems to indicate a non-PRX library (like "stdc" or "allocator") that comes from somewhere else (LV2?)
|-
| +6
| short
| Number of functions
|-
| +8
| short
| Number of variables
|-
| +10
| short
| Number of thread local storage variables
|-
| +12
| byte[4]
| reserved
|-
| +16
| long
| Pointer to imported library name.
|-
| +20
| long
| Pointer to the list of NID's for the exported functions.
|-
| +24
| long
| Pointer to the list of exported functions.
|-
| +28
| long
| var_nid_table
|-
| +32
| long
| var_entry_table
|-
| +36
| long
| tls_nid_table
|-
| +40
| long
| tls_entry_table
|}


== Recognition ==
== Relocations ==
Relocations can be found in either PT_SCE_PPURELA segments or SHT_SCE_PPURELA / SHT_RELA sections. RELA relocations are standard relocations while PPURELA relocations have 2 segment (program header) indexes stored in r_sym of r_info.
*The first index can be extracted with 0x7FFFFF00 as a mask and is used as a base address for r_addend. This sum will be the value applied to the patch.
*The second index can be extracted with 0x000000FF as a mask and is used as a base address for the target segment to patch and is added to r_offset.
*The first bit (0x80000000) is also set on earlier PRX's but it is currently unknown what it is used for.


A PRX module is PRX2 format only if ehdr.e_type is ET_SCE_EXEC or ET_SCE_RELEXEC.


A Program Segment is PRX2 format only if p_type is PT_SCE_RELA or PT_SCE_COMMENT.


= Module Info =
= FNID generation =


PS3 and PSP PRX embed Module Info version 0.
== symbol name suffix ==
symbol_name_suffix: 6759659904250490566427499489741A


== Location ==
To calculate FNID value of exported/imported symbol from .PRX you need to take SHA-1 hash over concatenation of symbol's name and symbol_name_suffix and then grab first 4 bytes from it and reverse these bytes (because of little-endian).
 
Let's take, for example, ''_sys_sprintf'':
For PS3 (?and PSP?), it is located in text segment (first LOAD segment) at offset Elf32_Phdrs[text_seg_id].p_paddr - Elf32_Phdrs[text_seg_id].p_offset. Or more simply: at offset Elf32_Phdrs[text_seg_id].p_paddr in the ELF file.
  ''SHA1''('_sys_sprintf' + '\x67\x59\x65\x99\x04\x25\x04\x90\x56\x64\x27\x49\x94\x89\x74\x1A') = '''FEEAF9A1'''23D7D1A7619B40CD52500F9735A852A4
 
   ''FNID''('_sys_sprintf') = ''swap_uint32''('''0xFEEAF9A1''') = '''0xA1F9EAFE'''.
== Structure ==
 
<source lang="C">
#define MODULE_NAME_MAX_LEN 27
 
typedef struct sceModuleInfo_common { // size is 0x20
   unsigned short modattr;
  unsigned char modver[2];
  char modname[MODULE_NAME_MAX_LEN];
  unsigned char infover;
} sceModuleInfo_common;
 
typedef struct sceModuleInfo_v0 { // size is 0x34
  sceModuleInfo_common c;
  Elf32_Addr gp_value;
  Elf32_Addr libent_top;
  Elf32_Addr libent_btm;
  Elf32_Addr libstub_top;
  Elf32_Addr libstub_btm;
} sceModuleInfo_v0;
</source>
 
= Exports =
 
PS3 uses exports structure of size 0x1C ?or 0x28 in 64bits?.
 
<source lang="C">
typedef struct _scelibent_common { // size is 0x10
unsigned char size;
unsigned char auxattribute;
unsigned short version;
unsigned short attribute;
unsigned short nfunc;
unsigned short nvar;
unsigned short ntls;
unsigned char hashinfo;
unsigned char hashinfotls;
unsigned char reserved;
unsigned char nidaltsets;
} sceKernelLibraryEntryTable_common;
 
typedef struct _scelibent_1C { // size is 0x1C
sceKernelLibraryEntryTable_common c;
Elf32_Addr libname;
Elf32_Addr nid_table;
Elf32_Addr entry_table;
} sceKernelLibraryEntryTable_1C;
</source>
 
= Imports =
 
PS3 use imports structures of size 0x2C.
 
<source lang="C">
typedef struct _scelibstub_common { // size is 0xC
unsigned short size;
unsigned short version;
unsigned short attribute;
unsigned short nfunc;
unsigned short nvar;
unsigned short ntls;
} sceKernelLibraryStubTable_common;
 
typedef struct _scelibstub_2C { // size is 0x2C
sceKernelLibraryStubTable_common c;
unsigned char reserved[4];
Elf32_Addr libname;
Elf32_Addr func_nid_table;
Elf32_Addr func_entry_table;
Elf32_Addr var_nid_table;
Elf32_Addr var_entry_table;
Elf32_Addr tls_nid_table;
Elf32_Addr tls_entry_table;
} sceKernelLibraryStubTable_2C;
</source>
 
= Relocations =
 
== PS3 ==
 
Relocations can be found in either PT_SCE_PPURELA segments or SHT_SCE_PPURELA / SHT_RELA sections. RELA relocations are standard relocations while PPURELA relocations have 2 segment (program header) indexes stored in r_sym of r_info.
*The first index can be extracted with 0x7FFFFF00 as a mask and is used as a base address for r_addend. This sum will be the value applied to the patch.
*The second index can be extracted with 0x000000FF as a mask and is used as a base address for the target segment to patch and is added to r_offset.
*The first bit (0x80000000) is also set on earlier PRXs but it is currently unknown what it is used for.


For C++ functions you should use mangled representation of symbol's name.
For example, mangled name of ''std::runtime_error::what() const'' is ''_ZNKSt13runtime_error4whatEv'' and FNID('_ZNKSt13runtime_error4whatEv') = '''0x5333BDC9'''.
More complex example:
FNID(mangle('std::basic_filebuf<wchar_t, std::char_traits<wchar_t> >::seekpos(std::fpos<std::
_Mbstatet>, std::_Iosb<int>::_Openmode)')) = FNID('_ZNSt13basic_filebufIwSt11char_traitsIwEE7seekposESt4fposISt9_MbstatetENSt5_IosbIiE9_OpenmodeE') = '''0xB6A4D760'''


noname_nid_suffix: 0xbc5eba9e042504905b64274994d9c41f
For import stub's with no names, you must use SHA1 over concatenation of symbol's name and noname_nid_suffix as an ascii string. Some examples of noname imports are module_start, module_info, and module_stop.
  ''SHA1''('module_info' + '0xbc5eba9e042504905b64274994d9c41f') = '''1630f4d7'''0bf3df419db9d481983411fd3130482a = '''0xD7F43016'''


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<noinclude>[[Category:Main]]</noinclude>
<noinclude>[[Category:Main]]</noinclude>
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