/****************************************************************************/ /* * linux/fs/binfmt_flat.c * * 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) */ #include <linux/export.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/mman.h> #include <linux/errno.h> #include <linux/signal.h> #include <linux/string.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/stat.h> #include <linux/fcntl.h> #include <linux/ptrace.h> #include <linux/user.h> #include <linux/slab.h> #include <linux/binfmts.h> #include <linux/personality.h> #include <linux/init.h> #include <linux/flat.h> #include <linux/syscalls.h> #include <asm/byteorder.h> #include <asm/uaccess.h> #include <asm/unaligned.h> #include <asm/cacheflush.h> #include <asm/page.h> /****************************************************************************/ #if 0 #define DEBUG 1 #endif #ifdef DEBUG #define DBG_FLT(a...) printk(a) #else #define DBG_FLT(a...) #endif /* * User data (data section and bss) needs to be aligned. * We pick 0x20 here because it is the max value elf2flt has always * used in producing FLAT files, and because it seems to be large * enough to make all the gcc alignment related tests happy. */ #define FLAT_DATA_ALIGN (0x20) /* * User data (stack) also needs to be aligned. * Here we can be a bit looser than the data sections since this * needs to only meet arch ABI requirements. */ #define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN) #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */ #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */ struct lib_info { struct { unsigned long start_code; /* Start of text segment */ unsigned long start_data; /* Start of data segment */ unsigned long start_brk; /* End of data segment */ unsigned long text_len; /* Length of text segment */ unsigned long entry; /* Start address for this module */ unsigned long build_date; /* When this one was compiled */ short loaded; /* Has this library been loaded? */ } lib_list[MAX_SHARED_LIBS]; }; #ifdef CONFIG_BINFMT_SHARED_FLAT static int load_flat_shared_library(int id, struct lib_info *p); #endif static int load_flat_binary(struct linux_binprm *, struct pt_regs * regs); static int flat_core_dump(struct coredump_params *cprm); static struct linux_binfmt flat_format = { .module = THIS_MODULE, .load_binary = load_flat_binary, .core_dump = flat_core_dump, .min_coredump = PAGE_SIZE }; /****************************************************************************/ /* * Routine writes a core dump image in the current directory. * Currently only a stub-function. */ static int flat_core_dump(struct coredump_params *cprm) { printk("Process %s:%d received signr %d and should have core dumped\n", current->comm, current->pid, (int) cprm->signr); return(1); } /****************************************************************************/ /* * 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. */ static unsigned long create_flat_tables( unsigned long pp, struct linux_binprm * bprm) { unsigned long *argv,*envp; unsigned long * sp; char * p = (char*)pp; int argc = bprm->argc; int envc = bprm->envc; char uninitialized_var(dummy); sp = (unsigned long *)p; sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0); sp = (unsigned long *) ((unsigned long)sp & -FLAT_STACK_ALIGN); argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0); envp = argv + (argc + 1); if (flat_argvp_envp_on_stack()) { put_user((unsigned long) envp, sp + 2); put_user((unsigned long) argv, sp + 1); } put_user(argc, sp); current->mm->arg_start = (unsigned long) p; while (argc-->0) { put_user((unsigned long) p, argv++); do { get_user(dummy, p); p++; } while (dummy); } put_user((unsigned long) NULL, argv); current->mm->arg_end = current->mm->env_start = (unsigned long) p; while (envc-->0) { put_user((unsigned long)p, envp); envp++; do { get_user(dummy, p); p++; } while (dummy); } put_user((unsigned long) NULL, envp); current->mm->env_end = (unsigned long) p; return (unsigned long)sp; } /****************************************************************************/ #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) { while (ret < LBUFSIZE && buf[ret++] != 0) ; if (unlikely(LBUFSIZE == ret)) { DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n"); goto out_free_buf; } } if (buf[3] & COMMENT) { while (ret < LBUFSIZE && buf[ret++] != 0) ; 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; 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); return retval; } #endif /* CONFIG_BINFMT_ZFLAT */ /****************************************************************************/ static unsigned long calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp) { unsigned long addr; int id; unsigned long start_brk; unsigned long start_data; unsigned long text_len; unsigned long start_code; #ifdef CONFIG_BINFMT_SHARED_FLAT 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) { printk("BINFMT_FLAT: reference 0x%x to shared library %d", (unsigned) r, id); goto failed; } if (curid != id) { if (internalp) { printk("BINFMT_FLAT: reloc address 0x%x not in same module " "(%d != %d)", (unsigned) r, curid, id); goto failed; } else if ( ! p->lib_list[id].loaded && IS_ERR_VALUE(load_flat_shared_library(id, p))) { printk("BINFMT_FLAT: failed to load library %d", id); goto failed; } /* Check versioning information (i.e. time stamps) */ if (p->lib_list[id].build_date && p->lib_list[curid].build_date && p->lib_list[curid].build_date < p->lib_list[id].build_date) { printk("BINFMT_FLAT: library %d is younger than %d", id, curid); goto failed; } } #else id = 0; #endif start_brk = p->lib_list[id].start_brk; start_data = p->lib_list[id].start_data; start_code = p->lib_list[id].start_code; text_len = p->lib_list[id].text_len; if (!flat_reloc_valid(r, start_brk - start_data + text_len)) { printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)", (int) r,(int)(start_brk-start_data+text_len),(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: printk(", killing %s!\n", current->comm); send_sig(SIGSEGV, current, 0); return RELOC_FAILED; } /****************************************************************************/ void old_reloc(unsigned long rl) { #ifdef DEBUG char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; #endif flat_v2_reloc_t r; unsigned long *ptr; r.value = rl; #if defined(CONFIG_COLDFIRE) ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset); #else ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset); #endif #ifdef DEBUG printk("Relocation of variable at DATASEG+%x " "(address %p, currently %x) into segment %s\n", r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]); #endif switch (r.reloc.type) { case OLD_FLAT_RELOC_TYPE_TEXT: *ptr += current->mm->start_code; break; case OLD_FLAT_RELOC_TYPE_DATA: *ptr += current->mm->start_data; break; case OLD_FLAT_RELOC_TYPE_BSS: *ptr += current->mm->end_data; break; default: printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type); break; } #ifdef DEBUG printk("Relocation became %x\n", (int)*ptr); #endif } /****************************************************************************/ static int load_flat_file(struct linux_binprm * bprm, struct lib_info *libinfo, int id, unsigned long *extra_stack) { struct flat_hdr * hdr; unsigned long textpos = 0, datapos = 0, result; unsigned long realdatastart = 0; unsigned long text_len, data_len, bss_len, stack_len, flags; unsigned long len, memp = 0; unsigned long memp_size, extra, rlim; unsigned long *reloc = 0, *rp; struct inode *inode; int i, rev, relocs = 0; loff_t fpos; unsigned long start_code, end_code; int ret; hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ inode = bprm->file->f_path.dentry->d_inode; 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); if (strncmp(hdr->magic, "bFLT", 4)) { /* * Previously, here was a printk to tell people * "BINFMT_FLAT: bad header magic". * But for the kernel which also use ELF FD-PIC format, this * error message is confusing. * because a lot of people do not manage to produce good */ ret = -ENOEXEC; goto err; } if (flags & FLAT_FLAG_KTRACE) printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename); if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { printk("BINFMT_FLAT: bad flat file version 0x%x (supported " "0x%lx and 0x%lx)\n", rev, FLAT_VERSION, OLD_FLAT_VERSION); ret = -ENOEXEC; goto err; } /* Don't allow old format executables to use shared libraries */ if (rev == OLD_FLAT_VERSION && id != 0) { printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n", (int) FLAT_VERSION); ret = -ENOEXEC; goto err; } /* * 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)) { printk("Support for ZFLAT executables is not enabled.\n"); ret = -ENOEXEC; goto err; } #endif /* * Check initial limits. This avoids letting people circumvent * size limits imposed on them by creating programs with large * arrays in the data or bss. */ rlim = rlimit(RLIMIT_DATA); if (rlim >= RLIM_INFINITY) rlim = ~0; if (data_len + bss_len > rlim) { ret = -ENOMEM; goto err; } /* Flush all traces of the currently running executable */ if (id == 0) { result = flush_old_exec(bprm); if (result) { ret = result; goto err; } /* OK, This is the point of no return */ set_personality(PER_LINUX_32BIT); setup_new_exec(bprm); } /* * calculate the extra space we need to map in */ extra = max_t(unsigned long, bss_len + stack_len, relocs * sizeof(unsigned long)); /* * 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 = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_EXECUTABLE, 0); if (!textpos || IS_ERR_VALUE(textpos)) { if (!textpos) textpos = (unsigned long) -ENOMEM; printk("Unable to mmap process text, errno %d\n", (int)-textpos); ret = textpos; goto err; } len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); len = PAGE_ALIGN(len); realdatastart = vm_mmap(0, 0, len, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { if (!realdatastart) realdatastart = (unsigned long) -ENOMEM; printk("Unable to allocate RAM for process data, errno %d\n", (int)-realdatastart); do_munmap(current->mm, textpos, text_len); ret = realdatastart; goto err; } datapos = ALIGN(realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long), FLAT_DATA_ALIGN); 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(unsigned long)), 0); } else #endif { result = bprm->file->f_op->read(bprm->file, (char *) datapos, data_len + (relocs * sizeof(unsigned long)), &fpos); } if (IS_ERR_VALUE(result)) { printk("Unable to read data+bss, errno %d\n", (int)-result); do_munmap(current->mm, textpos, text_len); do_munmap(current->mm, realdatastart, len); ret = result; goto err; } reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len)); memp = realdatastart; memp_size = len; } else { len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); len = PAGE_ALIGN(len); textpos = vm_mmap(0, 0, len, PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); if (!textpos || IS_ERR_VALUE(textpos)) { if (!textpos) textpos = (unsigned long) -ENOMEM; printk("Unable to allocate RAM for process text/data, errno %d\n", (int)-textpos); ret = textpos; goto err; } realdatastart = textpos + ntohl(hdr->data_start); datapos = ALIGN(realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long), FLAT_DATA_ALIGN); reloc = (unsigned long *) (datapos + (ntohl(hdr->reloc_start) - text_len)); memp = textpos; memp_size = len; #ifdef CONFIG_BINFMT_ZFLAT /* * 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_ERR_VALUE(result)) result = decompress_exec(bprm, text_len, (char *) datapos, data_len + (relocs * sizeof(unsigned long)), 0); } else #endif { fpos = 0; result = bprm->file->f_op->read(bprm->file, (char *) textpos, text_len, &fpos); if (!IS_ERR_VALUE(result)) { fpos = ntohl(hdr->data_start); result = bprm->file->f_op->read(bprm->file, (char *) datapos, data_len + (relocs * sizeof(unsigned long)), &fpos); } } if (IS_ERR_VALUE(result)) { printk("Unable to read code+data+bss, errno %d\n",(int)-result); do_munmap(current->mm, textpos, text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long)); ret = result; goto err; } } if (flags & FLAT_FLAG_KTRACE) printk("Mapping is %x, Entry point is %x, data_start is %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); end_code = textpos + text_len; if (id == 0) { current->mm->start_code = start_code; current->mm->end_code = end_code; current->mm->start_data = datapos; current->mm->end_data = datapos + data_len; /* * set up the brk stuff, uses any slack left in data/bss/stack * allocation. We put the brk after the bss (between the bss * and stack) like other platforms. * Userspace code relies on the stack pointer starting out at * an address right at the end of a page. */ current->mm->start_brk = datapos + data_len + bss_len; current->mm->brk = (current->mm->start_brk + 3) & ~3; current->mm->context.end_brk = memp + memp_size - stack_len; } if (flags & FLAT_FLAG_KTRACE) printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n", id ? "Lib" : "Load", bprm->filename, (int) start_code, (int) end_code, (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->lib_list[id].start_code = start_code; libinfo->lib_list[id].start_data = datapos; libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; libinfo->lib_list[id].text_len = text_len; libinfo->lib_list[id].loaded = 1; libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; libinfo->lib_list[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) { for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) { unsigned long addr; if (*rp) { addr = calc_reloc(*rp, libinfo, id, 0); if (addr == RELOC_FAILED) { ret = -ENOEXEC; goto err; } *rp = addr; } } } /* * 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) { unsigned long persistent = 0; for (i=0; i < relocs; i++) { unsigned long addr, relval; /* Get the address of the pointer to be relocated (of course, the address has to be relocated first). */ relval = ntohl(reloc[i]); if (flat_set_persistent (relval, &persistent)) continue; addr = flat_get_relocate_addr(relval); rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1); if (rp == (unsigned long *)RELOC_FAILED) { ret = -ENOEXEC; goto err; } /* Get the pointer's value. */ addr = flat_get_addr_from_rp(rp, 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) { ret = -ENOEXEC; goto err; } /* Write back the relocated pointer. */ flat_put_addr_at_rp(rp, addr, relval); } } } else { for (i=0; i < relocs; i++) old_reloc(ntohl(reloc[i])); } flush_icache_range(start_code, end_code); /* zero the BSS, BRK and stack areas */ memset((void*)(datapos + data_len), 0, bss_len + (memp + memp_size - stack_len - /* end brk */ libinfo->lib_list[id].start_brk) + /* start brk */ stack_len); return 0; err: return ret; } /****************************************************************************/ #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]; memset(&bprm, 0, sizeof(bprm)); /* 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; bprm.cred = prepare_exec_creds(); res = -ENOMEM; if (!bprm.cred) goto out; /* We don't really care about recalculating credentials at this point * as we're past the point of no return and are dealing with shared * libraries. */ bprm.cred_prepared = 1; res = prepare_binprm(&bprm); if (!IS_ERR_VALUE(res)) res = load_flat_file(&bprm, libs, id, NULL); abort_creds(bprm.cred); out: allow_write_access(bprm.file); fput(bprm.file); return(res); } #endif /* CONFIG_BINFMT_SHARED_FLAT */ /****************************************************************************/ /* * These are the functions used to load flat style executables and shared * libraries. There is no binary dependent code anywhere else. */ static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs) { struct lib_info libinfo; unsigned long p = bprm->p; unsigned long stack_len; unsigned long start_addr; unsigned long *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. */ #define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *)) stack_len = TOP_OF_ARGS - bprm->p; /* the strings */ stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ stack_len += FLAT_STACK_ALIGN - 1; /* reserve for upcoming alignment */ res = load_flat_file(bprm, &libinfo, 0, &stack_len); if (IS_ERR_VALUE(res)) return res; /* Update data segment pointers for all libraries */ for (i=0; i<MAX_SHARED_LIBS; i++) if (libinfo.lib_list[i].loaded) for (j=0; j<MAX_SHARED_LIBS; j++) (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] = (libinfo.lib_list[j].loaded)? libinfo.lib_list[j].start_data:UNLOADED_LIB; install_exec_creds(bprm); set_binfmt(&flat_format); p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4; DBG_FLT("p=%x\n", (int)p); /* copy the arg pages onto the stack, this could be more efficient :-) */ for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--) * (char *) --p = ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE]; sp = (unsigned long *) create_flat_tables(p, bprm); /* 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.lib_list[0].entry; #ifdef CONFIG_BINFMT_SHARED_FLAT for (i = MAX_SHARED_LIBS-1; i>0; i--) { if (libinfo.lib_list[i].loaded) { /* Push previos first to call address */ --sp; put_user(start_addr, sp); start_addr = libinfo.lib_list[i].entry; } } #endif /* Stash our initial stack pointer into the mm structure */ current->mm->start_stack = (unsigned long )sp; #ifdef FLAT_PLAT_INIT FLAT_PLAT_INIT(regs); #endif DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n", (int)regs, (int)start_addr, (int)current->mm->start_stack); start_thread(regs, start_addr, current->mm->start_stack); return 0; } /****************************************************************************/ static int __init init_flat_binfmt(void) { register_binfmt(&flat_format); return 0; } /****************************************************************************/ core_initcall(init_flat_binfmt); /****************************************************************************/