/****************************************************************************/ /* * QEMU bFLT binary loader. Based on linux/fs/binfmt_flat.c * * 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, see <http://www.gnu.org/licenses/>. * * Copyright (C) 2006 CodeSourcery. * Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com> * Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com> * Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com> * Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com> * based heavily on: * * linux/fs/binfmt_aout.c: * Copyright (C) 1991, 1992, 1996 Linus Torvalds * linux/fs/binfmt_flat.c for 2.0 kernel * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com> * JAN/99 -- coded full program relocation (gerg@snapgear.com) */ /* ??? ZFLAT and shared library support is currently disabled. */ /****************************************************************************/ #include "qemu/osdep.h" #include "qemu.h" #include "flat.h" #include <target_flat.h> //#define DEBUG #ifdef DEBUG #define DBG_FLT(...) printf(__VA_ARGS__) #else #define DBG_FLT(...) #endif #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */ #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */ struct lib_info { abi_ulong start_code; /* Start of text segment */ abi_ulong start_data; /* Start of data segment */ abi_ulong end_data; /* Start of bss section */ abi_ulong start_brk; /* End of data segment */ abi_ulong text_len; /* Length of text segment */ abi_ulong entry; /* Start address for this module */ abi_ulong build_date; /* When this one was compiled */ short loaded; /* Has this library been loaded? */ }; #ifdef CONFIG_BINFMT_SHARED_FLAT static int load_flat_shared_library(int id, struct lib_info *p); #endif struct linux_binprm; /****************************************************************************/ /* * create_flat_tables() parses the env- and arg-strings in new user * memory and creates the pointer tables from them, and puts their * addresses on the "stack", returning the new stack pointer value. */ /* Push a block of strings onto the guest stack. */ static abi_ulong copy_strings(abi_ulong p, int n, char **s) { int len; while (n-- > 0) { len = strlen(s[n]) + 1; p -= len; memcpy_to_target(p, s[n], len); } return p; } static int target_pread(int fd, abi_ulong ptr, abi_ulong len, abi_ulong offset) { void *buf; int ret; buf = lock_user(VERIFY_WRITE, ptr, len, 0); if (!buf) { return -EFAULT; } ret = pread(fd, buf, len, offset); if (ret < 0) { ret = -errno; } unlock_user(buf, ptr, len); return ret; } /****************************************************************************/ #ifdef CONFIG_BINFMT_ZFLAT #include <linux/zlib.h> #define LBUFSIZE 4000 /* gzip flag byte */ #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ #define COMMENT 0x10 /* bit 4 set: file comment present */ #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ #define RESERVED 0xC0 /* bit 6,7: reserved */ static int decompress_exec( struct linux_binprm *bprm, unsigned long offset, char *dst, long len, int fd) { unsigned char *buf; z_stream strm; loff_t fpos; int ret, retval; DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len); memset(&strm, 0, sizeof(strm)); strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); if (strm.workspace == NULL) { DBG_FLT("binfmt_flat: no memory for decompress workspace\n"); return -ENOMEM; } buf = kmalloc(LBUFSIZE, GFP_KERNEL); if (buf == NULL) { DBG_FLT("binfmt_flat: no memory for read buffer\n"); retval = -ENOMEM; goto out_free; } /* Read in first chunk of data and parse gzip header. */ fpos = offset; ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos); strm.next_in = buf; strm.avail_in = ret; strm.total_in = 0; retval = -ENOEXEC; /* Check minimum size -- gzip header */ if (ret < 10) { DBG_FLT("binfmt_flat: file too small?\n"); goto out_free_buf; } /* Check gzip magic number */ if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { DBG_FLT("binfmt_flat: unknown compression magic?\n"); goto out_free_buf; } /* Check gzip method */ if (buf[2] != 8) { DBG_FLT("binfmt_flat: unknown compression method?\n"); goto out_free_buf; } /* Check gzip flags */ if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || (buf[3] & RESERVED)) { DBG_FLT("binfmt_flat: unknown flags?\n"); goto out_free_buf; } ret = 10; if (buf[3] & EXTRA_FIELD) { ret += 2 + buf[10] + (buf[11] << 8); if (unlikely(LBUFSIZE == ret)) { DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n"); goto out_free_buf; } } if (buf[3] & ORIG_NAME) { for (; ret < LBUFSIZE && (buf[ret] != 0); ret++) ; if (unlikely(LBUFSIZE == ret)) { DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n"); goto out_free_buf; } } if (buf[3] & COMMENT) { for (; ret < LBUFSIZE && (buf[ret] != 0); ret++) ; if (unlikely(LBUFSIZE == ret)) { DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n"); goto out_free_buf; } } strm.next_in += ret; strm.avail_in -= ret; strm.next_out = dst; strm.avail_out = len; strm.total_out = 0; if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { DBG_FLT("binfmt_flat: zlib init failed?\n"); goto out_free_buf; } while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos); if (ret <= 0) break; if (is_error(ret)) { break; } len -= ret; strm.next_in = buf; strm.avail_in = ret; strm.total_in = 0; } if (ret < 0) { DBG_FLT("binfmt_flat: decompression failed (%d), %s\n", ret, strm.msg); goto out_zlib; } retval = 0; out_zlib: zlib_inflateEnd(&strm); out_free_buf: kfree(buf); out_free: kfree(strm.workspace); out: return retval; } #endif /* CONFIG_BINFMT_ZFLAT */ /****************************************************************************/ static abi_ulong calc_reloc(abi_ulong r, struct lib_info *p, int curid, int internalp) { abi_ulong addr; int id; abi_ulong start_brk; abi_ulong start_data; abi_ulong text_len; abi_ulong start_code; #ifdef CONFIG_BINFMT_SHARED_FLAT #error needs checking if (r == 0) id = curid; /* Relocs of 0 are always self referring */ else { id = (r >> 24) & 0xff; /* Find ID for this reloc */ r &= 0x00ffffff; /* Trim ID off here */ } if (id >= MAX_SHARED_LIBS) { fprintf(stderr, "BINFMT_FLAT: reference 0x%x to shared library %d\n", (unsigned) r, id); goto failed; } if (curid != id) { if (internalp) { fprintf(stderr, "BINFMT_FLAT: reloc address 0x%x not " "in same module (%d != %d)\n", (unsigned) r, curid, id); goto failed; } else if (!p[id].loaded && is_error(load_flat_shared_library(id, p))) { fprintf(stderr, "BINFMT_FLAT: failed to load library %d\n", id); goto failed; } /* Check versioning information (i.e. time stamps) */ if (p[id].build_date && p[curid].build_date && p[curid].build_date < p[id].build_date) { fprintf(stderr, "BINFMT_FLAT: library %d is younger than %d\n", id, curid); goto failed; } } #else id = 0; #endif start_brk = p[id].start_brk; start_data = p[id].start_data; start_code = p[id].start_code; text_len = p[id].text_len; if (!flat_reloc_valid(r, start_brk - start_data + text_len)) { fprintf(stderr, "BINFMT_FLAT: reloc outside program 0x%x " "(0 - 0x%x/0x%x)\n", (int) r,(int)(start_brk-start_code),(int)text_len); goto failed; } if (r < text_len) /* In text segment */ addr = r + start_code; else /* In data segment */ addr = r - text_len + start_data; /* Range checked already above so doing the range tests is redundant...*/ return(addr); failed: abort(); return RELOC_FAILED; } /****************************************************************************/ /* ??? This does not handle endianness correctly. */ static void old_reloc(struct lib_info *libinfo, uint32_t rl) { #ifdef DEBUG const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; #endif uint32_t *ptr; uint32_t offset; int reloc_type; offset = rl & 0x3fffffff; reloc_type = rl >> 30; /* ??? How to handle this? */ #if defined(CONFIG_COLDFIRE) ptr = (uint32_t *) ((unsigned long) libinfo->start_code + offset); #else ptr = (uint32_t *) ((unsigned long) libinfo->start_data + offset); #endif #ifdef DEBUG fprintf(stderr, "Relocation of variable at DATASEG+%x " "(address %p, currently %x) into segment %s\n", offset, ptr, (int)*ptr, segment[reloc_type]); #endif switch (reloc_type) { case OLD_FLAT_RELOC_TYPE_TEXT: *ptr += libinfo->start_code; break; case OLD_FLAT_RELOC_TYPE_DATA: *ptr += libinfo->start_data; break; case OLD_FLAT_RELOC_TYPE_BSS: *ptr += libinfo->end_data; break; default: fprintf(stderr, "BINFMT_FLAT: Unknown relocation type=%x\n", reloc_type); break; } DBG_FLT("Relocation became %x\n", (int)*ptr); } /****************************************************************************/ static int load_flat_file(struct linux_binprm * bprm, struct lib_info *libinfo, int id, abi_ulong *extra_stack) { struct flat_hdr * hdr; abi_ulong textpos = 0, datapos = 0; abi_long result; abi_ulong realdatastart = 0; abi_ulong text_len, data_len, bss_len, stack_len, flags; abi_ulong extra; abi_ulong reloc = 0, rp; int i, rev, relocs = 0; abi_ulong fpos; abi_ulong start_code; abi_ulong indx_len; hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ text_len = ntohl(hdr->data_start); data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); stack_len = ntohl(hdr->stack_size); if (extra_stack) { stack_len += *extra_stack; *extra_stack = stack_len; } relocs = ntohl(hdr->reloc_count); flags = ntohl(hdr->flags); rev = ntohl(hdr->rev); DBG_FLT("BINFMT_FLAT: Loading file: %s\n", bprm->filename); if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { fprintf(stderr, "BINFMT_FLAT: bad magic/rev (0x%x, need 0x%x)\n", rev, (int) FLAT_VERSION); return -ENOEXEC; } /* Don't allow old format executables to use shared libraries */ if (rev == OLD_FLAT_VERSION && id != 0) { fprintf(stderr, "BINFMT_FLAT: shared libraries are not available\n"); return -ENOEXEC; } /* * fix up the flags for the older format, there were all kinds * of endian hacks, this only works for the simple cases */ if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags)) flags = FLAT_FLAG_RAM; #ifndef CONFIG_BINFMT_ZFLAT if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { fprintf(stderr, "Support for ZFLAT executables is not enabled\n"); return -ENOEXEC; } #endif /* * calculate the extra space we need to map in */ extra = relocs * sizeof(abi_ulong); if (extra < bss_len + stack_len) extra = bss_len + stack_len; /* Add space for library base pointers. Make sure this does not misalign the doesn't misalign the data segment. */ indx_len = MAX_SHARED_LIBS * sizeof(abi_ulong); indx_len = (indx_len + 15) & ~(abi_ulong)15; /* * there are a couple of cases here, the separate code/data * case, and then the fully copied to RAM case which lumps * it all together. */ if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) { /* * this should give us a ROM ptr, but if it doesn't we don't * really care */ DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n"); textpos = target_mmap(0, text_len, PROT_READ|PROT_EXEC, MAP_PRIVATE, bprm->fd, 0); if (textpos == -1) { fprintf(stderr, "Unable to mmap process text\n"); return -1; } realdatastart = target_mmap(0, data_len + extra + indx_len, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (realdatastart == -1) { fprintf(stderr, "Unable to allocate RAM for process data\n"); return realdatastart; } datapos = realdatastart + indx_len; DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n", (int)(data_len + bss_len + stack_len), (int)datapos); fpos = ntohl(hdr->data_start); #ifdef CONFIG_BINFMT_ZFLAT if (flags & FLAT_FLAG_GZDATA) { result = decompress_exec(bprm, fpos, (char *) datapos, data_len + (relocs * sizeof(abi_ulong))) } else #endif { result = target_pread(bprm->fd, datapos, data_len + (relocs * sizeof(abi_ulong)), fpos); } if (result < 0) { fprintf(stderr, "Unable to read data+bss\n"); return result; } reloc = datapos + (ntohl(hdr->reloc_start) - text_len); } else { textpos = target_mmap(0, text_len + data_len + extra + indx_len, PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (textpos == -1 ) { fprintf(stderr, "Unable to allocate RAM for process text/data\n"); return -1; } realdatastart = textpos + ntohl(hdr->data_start); datapos = realdatastart + indx_len; reloc = (textpos + ntohl(hdr->reloc_start) + indx_len); #ifdef CONFIG_BINFMT_ZFLAT #error code needs checking /* * load it all in and treat it like a RAM load from now on */ if (flags & FLAT_FLAG_GZIP) { result = decompress_exec(bprm, sizeof (struct flat_hdr), (((char *) textpos) + sizeof (struct flat_hdr)), (text_len + data_len + (relocs * sizeof(unsigned long)) - sizeof (struct flat_hdr)), 0); memmove((void *) datapos, (void *) realdatastart, data_len + (relocs * sizeof(unsigned long))); } else if (flags & FLAT_FLAG_GZDATA) { fpos = 0; result = bprm->file->f_op->read(bprm->file, (char *) textpos, text_len, &fpos); if (!is_error(result)) { result = decompress_exec(bprm, text_len, (char *) datapos, data_len + (relocs * sizeof(unsigned long)), 0); } } else #endif { result = target_pread(bprm->fd, textpos, text_len, 0); if (result >= 0) { result = target_pread(bprm->fd, datapos, data_len + (relocs * sizeof(abi_ulong)), ntohl(hdr->data_start)); } } if (result < 0) { fprintf(stderr, "Unable to read code+data+bss\n"); return result; } } DBG_FLT("Mapping is 0x%x, Entry point is 0x%x, data_start is 0x%x\n", (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); /* The main program needs a little extra setup in the task structure */ start_code = textpos + sizeof (struct flat_hdr); DBG_FLT("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n", id ? "Lib" : "Load", bprm->filename, (int) start_code, (int) (textpos + text_len), (int) datapos, (int) (datapos + data_len), (int) (datapos + data_len), (int) (((datapos + data_len + bss_len) + 3) & ~3)); text_len -= sizeof(struct flat_hdr); /* the real code len */ /* Store the current module values into the global library structure */ libinfo[id].start_code = start_code; libinfo[id].start_data = datapos; libinfo[id].end_data = datapos + data_len; libinfo[id].start_brk = datapos + data_len + bss_len; libinfo[id].text_len = text_len; libinfo[id].loaded = 1; libinfo[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; libinfo[id].build_date = ntohl(hdr->build_date); /* * We just load the allocations into some temporary memory to * help simplify all this mumbo jumbo * * We've got two different sections of relocation entries. * The first is the GOT which resides at the beginning of the data segment * and is terminated with a -1. This one can be relocated in place. * The second is the extra relocation entries tacked after the image's * data segment. These require a little more processing as the entry is * really an offset into the image which contains an offset into the * image. */ if (flags & FLAT_FLAG_GOTPIC) { rp = datapos; while (1) { abi_ulong addr; if (get_user_ual(addr, rp)) return -EFAULT; if (addr == -1) break; if (addr) { addr = calc_reloc(addr, libinfo, id, 0); if (addr == RELOC_FAILED) return -ENOEXEC; if (put_user_ual(addr, rp)) return -EFAULT; } rp += sizeof(abi_ulong); } } /* * Now run through the relocation entries. * We've got to be careful here as C++ produces relocatable zero * entries in the constructor and destructor tables which are then * tested for being not zero (which will always occur unless we're * based from address zero). This causes an endless loop as __start * is at zero. The solution used is to not relocate zero addresses. * This has the negative side effect of not allowing a global data * reference to be statically initialised to _stext (I've moved * __start to address 4 so that is okay). */ if (rev > OLD_FLAT_VERSION) { abi_ulong persistent = 0; for (i = 0; i < relocs; i++) { abi_ulong addr, relval; /* Get the address of the pointer to be relocated (of course, the address has to be relocated first). */ if (get_user_ual(relval, reloc + i * sizeof(abi_ulong))) return -EFAULT; relval = ntohl(relval); if (flat_set_persistent(relval, &persistent)) continue; addr = flat_get_relocate_addr(relval); rp = calc_reloc(addr, libinfo, id, 1); if (rp == RELOC_FAILED) return -ENOEXEC; /* Get the pointer's value. */ if (get_user_ual(addr, rp)) return -EFAULT; addr = flat_get_addr_from_rp(addr, relval, flags, &persistent); if (addr != 0) { /* * Do the relocation. PIC relocs in the data section are * already in target order */ if ((flags & FLAT_FLAG_GOTPIC) == 0) addr = ntohl(addr); addr = calc_reloc(addr, libinfo, id, 0); if (addr == RELOC_FAILED) return -ENOEXEC; /* Write back the relocated pointer. */ if (flat_put_addr_at_rp(rp, addr, relval)) return -EFAULT; } } } else { for (i = 0; i < relocs; i++) { abi_ulong relval; if (get_user_ual(relval, reloc + i * sizeof(abi_ulong))) return -EFAULT; old_reloc(&libinfo[0], relval); } } /* zero the BSS. */ memset(g2h(datapos + data_len), 0, bss_len); return 0; } /****************************************************************************/ #ifdef CONFIG_BINFMT_SHARED_FLAT /* * Load a shared library into memory. The library gets its own data * segment (including bss) but not argv/argc/environ. */ static int load_flat_shared_library(int id, struct lib_info *libs) { struct linux_binprm bprm; int res; char buf[16]; /* Create the file name */ sprintf(buf, "/lib/lib%d.so", id); /* Open the file up */ bprm.filename = buf; bprm.file = open_exec(bprm.filename); res = PTR_ERR(bprm.file); if (IS_ERR(bprm.file)) return res; res = prepare_binprm(&bprm); if (!is_error(res)) { res = load_flat_file(&bprm, libs, id, NULL); } if (bprm.file) { allow_write_access(bprm.file); fput(bprm.file); bprm.file = NULL; } return(res); } #endif /* CONFIG_BINFMT_SHARED_FLAT */ int load_flt_binary(struct linux_binprm *bprm, struct image_info *info) { struct lib_info libinfo[MAX_SHARED_LIBS]; abi_ulong p; abi_ulong stack_len; abi_ulong start_addr; abi_ulong sp; int res; int i, j; memset(libinfo, 0, sizeof(libinfo)); /* * We have to add the size of our arguments to our stack size * otherwise it's too easy for users to create stack overflows * by passing in a huge argument list. And yes, we have to be * pedantic and include space for the argv/envp array as it may have * a lot of entries. */ stack_len = 0; for (i = 0; i < bprm->argc; ++i) { /* the argv strings */ stack_len += strlen(bprm->argv[i]); } for (i = 0; i < bprm->envc; ++i) { /* the envp strings */ stack_len += strlen(bprm->envp[i]); } stack_len += (bprm->argc + 1) * 4; /* the argv array */ stack_len += (bprm->envc + 1) * 4; /* the envp array */ res = load_flat_file(bprm, libinfo, 0, &stack_len); if (is_error(res)) { return res; } /* Update data segment pointers for all libraries */ for (i=0; i<MAX_SHARED_LIBS; i++) { if (libinfo[i].loaded) { abi_ulong p; p = libinfo[i].start_data; for (j=0; j<MAX_SHARED_LIBS; j++) { p -= 4; /* FIXME - handle put_user() failures */ if (put_user_ual(libinfo[j].loaded ? libinfo[j].start_data : UNLOADED_LIB, p)) return -EFAULT; } } } p = ((libinfo[0].start_brk + stack_len + 3) & ~3) - 4; DBG_FLT("p=%x\n", (int)p); /* Copy argv/envp. */ p = copy_strings(p, bprm->envc, bprm->envp); p = copy_strings(p, bprm->argc, bprm->argv); /* Align stack. */ sp = p & ~(abi_ulong)(sizeof(abi_ulong) - 1); /* Enforce final stack alignment of 16 bytes. This is sufficient for all current targets, and excess alignment is harmless. */ stack_len = bprm->envc + bprm->argc + 2; stack_len += 3; /* argc, arvg, argp */ stack_len *= sizeof(abi_ulong); if ((sp + stack_len) & 15) sp -= 16 - ((sp + stack_len) & 15); sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p, flat_argvp_envp_on_stack()); /* Fake some return addresses to ensure the call chain will * initialise library in order for us. We are required to call * lib 1 first, then 2, ... and finally the main program (id 0). */ start_addr = libinfo[0].entry; #ifdef CONFIG_BINFMT_SHARED_FLAT #error here for (i = MAX_SHARED_LIBS-1; i>0; i--) { if (libinfo[i].loaded) { /* Push previos first to call address */ --sp; if (put_user_ual(start_addr, sp)) return -EFAULT; start_addr = libinfo[i].entry; } } #endif /* Stash our initial stack pointer into the mm structure */ info->start_code = libinfo[0].start_code; info->end_code = libinfo[0].start_code = libinfo[0].text_len; info->start_data = libinfo[0].start_data; info->end_data = libinfo[0].end_data; info->start_brk = libinfo[0].start_brk; info->start_stack = sp; info->stack_limit = libinfo[0].start_brk; info->entry = start_addr; info->code_offset = info->start_code; info->data_offset = info->start_data - libinfo[0].text_len; DBG_FLT("start_thread(entry=0x%x, start_stack=0x%x)\n", (int)info->entry, (int)info->start_stack); return 0; }