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author | Tony Puccinelli | 2010-06-19 02:39:11 +0000 |
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committer | Tony Puccinelli | 2010-06-19 02:39:11 +0000 |
commit | df6359d7435e7410488fd29555996b7230b88ac0 (patch) | |
tree | 1708ee53b0815c722c64b8f28a86464a457c650c /backends/platform/gp2xwiz/gp2xwiz-loader.cpp | |
parent | 1d714c0694eaf7ac7290eab93f6f99e67439ca6b (diff) | |
download | scummvm-rg350-df6359d7435e7410488fd29555996b7230b88ac0.tar.gz scummvm-rg350-df6359d7435e7410488fd29555996b7230b88ac0.tar.bz2 scummvm-rg350-df6359d7435e7410488fd29555996b7230b88ac0.zip |
added pretty skeletal loader
svn-id: r50036
Diffstat (limited to 'backends/platform/gp2xwiz/gp2xwiz-loader.cpp')
-rw-r--r-- | backends/platform/gp2xwiz/gp2xwiz-loader.cpp | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/backends/platform/gp2xwiz/gp2xwiz-loader.cpp b/backends/platform/gp2xwiz/gp2xwiz-loader.cpp new file mode 100644 index 0000000000..7acc4ee0d0 --- /dev/null +++ b/backends/platform/gp2xwiz/gp2xwiz-loader.cpp @@ -0,0 +1,255 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + + * This program 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 for more details. + + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * $URL$ + * $Id$ + * + */ + +#if defined(DYNAMIC_MODULES) && defined(__GP2X__) + +#include <string.h> +#include <stdarg.h> +#include <stdarg.h> +#include <stdio.h> +#include <malloc.h> +#include <unistd.h> + +#include "gp2xwiz-loader.h" + +#ifdef __WIZ_DEBUG_PLUGINS__ +#define DBG(x) printf(x, ## __VA_ARGS__) +#else +#define DBG(x) +#endif + +#define seterror(x,...) fprintf(stderr,x, ## __VA_ARGS__) + +// Expel the symbol table from memory +void DLObject::discard_symtab() +{ + free(_symtab); + free(_strtab); + _symtab = NULL; + _strtab = NULL; + _symbol_cnt = 0; +} + +// Unload all objects from memory +void DLObject::unload() +{ + discard_symtab(); + free(_segment); + segment = NULL; +} + +/** + * Follow the instruction of a relocation section. + * + * @param fd File Descriptor + * @param offset Offset into the File + * @param size Size of relocation section + * + */ +bool DLObject::relocate(int fd, unsigned long offset, unsigned long size) +{ + Elf32_Rela *rela; //relocation entry + + // Allocate memory for relocation table + if (!(rela = (Elf32_Rela *)malloc(size))) { + seterror("Out of memory."); + return false; + } + + // Read in our relocation table + if (lseek(fd, offset, SEEK_SET)<0 || + read(fd, rela, size) != (ssize_t)size) { + seterror("Relocation table load failed."); + free(rela); + return false; + } + + // Treat each relocation entry. Loop over all of them + int cnt = size / sizeof(*rela); + + // TODO: Loop over relocation entries + for (int i=0; i<cnt; i++) { + + Elf32_Sym *sym = ???; + + void *target = ???; + + switch(/*relocation type*/) { + case ???: + //TODO: Cases for each relocation type. + break; + default: + seterror("Unknown relocation type %d.", ???); + free(rela); + return false; + } + + } + + free(rela); + return true; +} + + +bool DLObject::load(int fd) +{ + Elf32_Ehdr ehdr; // ELF header + Elf32_Phdr phdr; // Program header + Elf32_Shdr *shdr; // Section header + + //TODO: fill this out! + + free(shdr); + + return true; +} + +bool DLObject::open(const char *path) +{ + int fd; + void *ctors_start, *ctors_end; + + DBG(("open(\"%s\")\n", path)); + + if ((fd = ::open(path, O_RDONLY))<0) { + seterror("%s not found.", path); + return false; + } + + // Try to load and relocate + if (!load(fd)) { + ::close(fd); + unload(); + return false; + } + + ::close(fd); + + //TODO: flush data cache + + ctors_start = symbol("___plugin_ctors"); + ctors_end = symbol("___plugin_ctors_end"); + _dtors_start = symbol("___plugin_dtors"); + _dtors_end = symbol("___plugin_dtors_end"); + + if (ctors_start == NULL || ctors_end == NULL || _dtors_start == NULL || + _dtors_end == NULL) { + seterror("Missing ctors/dtors."); + _dtors_start = _dtors_end = NULL; + unload(); + return false; + } + + DBG(("Calling constructors.\n")); + for (void (**f)(void) = (void (**)(void))ctors_start; f != ctors_end; f++) + (**f)(); + + DBG(("%s opened ok.\n", path)); + return true; +} + +bool DLObject::close() +{ + if (_dtors_start != NULL && _dtors_end != NULL) + for (void (**f)(void) = (void (**)(void))_dtors_start; f != _dtors_end; f++) + (**f)(); + _dtors_start = _dtors_end = NULL; + unload(); + return true; +} + +void *DLObject::symbol(const char *name) +{ + DBG(("symbol(\"%s\")\n", name)); + + if (_symtab == NULL || _strtab == NULL || _symbol_cnt < 1) { + seterror("No symbol table loaded."); + return NULL; + } + + Elf32_Sym *s = (Elf32_Sym *)_symtab; + for (int c = symbol_cnt; c--; s++) + + //TODO: Figure out which symbols should be detected here + if ((s->st_info>>4 == 1 || s->st_info>>4 == 2) && + strtab[s->st_name] == '_' && !strcmp(name, strtab+s->st_name+1)) { + + // We found the symbol + DBG(("=> %p\n", (void*)s->st_value)); + return (void*)s->st_value; + } + + // We didn't find the symbol + seterror("Symbol \"%s\" not found.", name); + return NULL; +} + + +static char dlerr[MAXDLERRLEN]; + +void *dlopen(const char *filename, int flags) +{ + DLObject *obj = new DLObject(dlerr); + if (obj->open(filename)) + return (void *)obj; + delete obj; + return NULL; +} + +int dlclose(void *handle) +{ + DLObject *obj = (DLObject *)handle; + if (obj == NULL) { + strcpy(dlerr, "Handle is NULL."); + return -1; + } + if (obj->close()) { + delete obj; + return 0; + } + return -1; +} + +void *dlsym(void *handle, const char *symbol) +{ + if (handle == NULL) { + strcpy(dlerr, "Handle is NULL."); + return NULL; + } + return ((DLObject *)handle)->symbol(symbol); +} + +const char *dlerror() +{ + return dlerr; +} + +void dlforgetsyms(void *handle) +{ + if (handle != NULL) + ((DLObject *)handle)->discard_symtab(); +} + +#endif /* DYNAMIC_MODULES && __GP2X__WIZ__ */ |