diff options
Diffstat (limited to 'fs/binfmt_flat.c')
| -rw-r--r-- | fs/binfmt_flat.c | 953 |
1 files changed, 953 insertions, 0 deletions
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c new file mode 100644 index 000000000..f723cd3a4 --- /dev/null +++ b/fs/binfmt_flat.c @@ -0,0 +1,953 @@ +/****************************************************************************/ +/* + * 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 *); +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->siginfo->si_signo); + 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 = kernel_read(bprm->file, offset, buf, LBUFSIZE); + + strm.next_in = buf; + strm.avail_in = ret; + strm.total_in = 0; + fpos += ret; + + 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 = kernel_read(bprm->file, fpos, buf, LBUFSIZE); + if (ret <= 0) + break; + len -= ret; + + strm.next_in = buf; + strm.avail_in = ret; + strm.total_in = 0; + fpos += ret; + } + + 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; +} + +/****************************************************************************/ + +static 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 full_data; + 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 = file_inode(bprm->file); + + 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); + full_data = data_len + relocs * sizeof(unsigned long); + + 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); + vm_munmap(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, + full_data, 0); + } else +#endif + { + result = read_code(bprm->file, datapos, fpos, + full_data); + } + if (IS_ERR_VALUE(result)) { + printk("Unable to read data+bss, errno %d\n", (int)-result); + vm_munmap(textpos, text_len); + vm_munmap(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 + full_data + - sizeof (struct flat_hdr)), + 0); + memmove((void *) datapos, (void *) realdatastart, + full_data); + } else if (flags & FLAT_FLAG_GZDATA) { + result = read_code(bprm->file, textpos, 0, text_len); + if (!IS_ERR_VALUE(result)) + result = decompress_exec(bprm, text_len, (char *) datapos, + full_data, 0); + } + else +#endif + { + result = read_code(bprm->file, textpos, 0, text_len); + if (!IS_ERR_VALUE(result)) + result = read_code(bprm->file, datapos, + ntohl(hdr->data_start), + full_data); + } + if (IS_ERR_VALUE(result)) { + printk("Unable to read code+data+bss, errno %d\n",(int)-result); + vm_munmap(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 lib_info libinfo; + struct pt_regs *regs = current_pt_regs(); + 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); + +/****************************************************************************/ |