Root/fs/binfmt_flat.c

1/****************************************************************************/
2/*
3 * linux/fs/binfmt_flat.c
4 *
5 * Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
6 * Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
7 * Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
8 * Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
9 * based heavily on:
10 *
11 * linux/fs/binfmt_aout.c:
12 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
13 * linux/fs/binfmt_flat.c for 2.0 kernel
14 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
15 * JAN/99 -- coded full program relocation (gerg@snapgear.com)
16 */
17
18#include <linux/module.h>
19#include <linux/kernel.h>
20#include <linux/sched.h>
21#include <linux/mm.h>
22#include <linux/mman.h>
23#include <linux/errno.h>
24#include <linux/signal.h>
25#include <linux/string.h>
26#include <linux/fs.h>
27#include <linux/file.h>
28#include <linux/stat.h>
29#include <linux/fcntl.h>
30#include <linux/ptrace.h>
31#include <linux/user.h>
32#include <linux/slab.h>
33#include <linux/binfmts.h>
34#include <linux/personality.h>
35#include <linux/init.h>
36#include <linux/flat.h>
37#include <linux/syscalls.h>
38
39#include <asm/byteorder.h>
40#include <asm/system.h>
41#include <asm/uaccess.h>
42#include <asm/unaligned.h>
43#include <asm/cacheflush.h>
44#include <asm/page.h>
45
46/****************************************************************************/
47
48#if 0
49#define DEBUG 1
50#endif
51
52#ifdef DEBUG
53#define DBG_FLT(a...) printk(a)
54#else
55#define DBG_FLT(a...)
56#endif
57
58/*
59 * User data (stack, data section and bss) needs to be aligned
60 * for the same reasons as SLAB memory is, and to the same amount.
61 * Avoid duplicating architecture specific code by using the same
62 * macro as with SLAB allocation:
63 */
64#ifdef ARCH_SLAB_MINALIGN
65#define FLAT_DATA_ALIGN (ARCH_SLAB_MINALIGN)
66#else
67#define FLAT_DATA_ALIGN (sizeof(void *))
68#endif
69
70#define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
71#define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */
72
73struct lib_info {
74    struct {
75        unsigned long start_code; /* Start of text segment */
76        unsigned long start_data; /* Start of data segment */
77        unsigned long start_brk; /* End of data segment */
78        unsigned long text_len; /* Length of text segment */
79        unsigned long entry; /* Start address for this module */
80        unsigned long build_date; /* When this one was compiled */
81        short loaded; /* Has this library been loaded? */
82    } lib_list[MAX_SHARED_LIBS];
83};
84
85#ifdef CONFIG_BINFMT_SHARED_FLAT
86static int load_flat_shared_library(int id, struct lib_info *p);
87#endif
88
89static int load_flat_binary(struct linux_binprm *, struct pt_regs * regs);
90static int flat_core_dump(struct coredump_params *cprm);
91
92static struct linux_binfmt flat_format = {
93    .module = THIS_MODULE,
94    .load_binary = load_flat_binary,
95    .core_dump = flat_core_dump,
96    .min_coredump = PAGE_SIZE
97};
98
99/****************************************************************************/
100/*
101 * Routine writes a core dump image in the current directory.
102 * Currently only a stub-function.
103 */
104
105static int flat_core_dump(struct coredump_params *cprm)
106{
107    printk("Process %s:%d received signr %d and should have core dumped\n",
108            current->comm, current->pid, (int) cprm->signr);
109    return(1);
110}
111
112/****************************************************************************/
113/*
114 * create_flat_tables() parses the env- and arg-strings in new user
115 * memory and creates the pointer tables from them, and puts their
116 * addresses on the "stack", returning the new stack pointer value.
117 */
118
119static unsigned long create_flat_tables(
120    unsigned long pp,
121    struct linux_binprm * bprm)
122{
123    unsigned long *argv,*envp;
124    unsigned long * sp;
125    char * p = (char*)pp;
126    int argc = bprm->argc;
127    int envc = bprm->envc;
128    char uninitialized_var(dummy);
129
130    sp = (unsigned long *)p;
131    sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
132    sp = (unsigned long *) ((unsigned long)sp & -FLAT_DATA_ALIGN);
133    argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
134    envp = argv + (argc + 1);
135
136    if (flat_argvp_envp_on_stack()) {
137        put_user((unsigned long) envp, sp + 2);
138        put_user((unsigned long) argv, sp + 1);
139    }
140
141    put_user(argc, sp);
142    current->mm->arg_start = (unsigned long) p;
143    while (argc-->0) {
144        put_user((unsigned long) p, argv++);
145        do {
146            get_user(dummy, p); p++;
147        } while (dummy);
148    }
149    put_user((unsigned long) NULL, argv);
150    current->mm->arg_end = current->mm->env_start = (unsigned long) p;
151    while (envc-->0) {
152        put_user((unsigned long)p, envp); envp++;
153        do {
154            get_user(dummy, p); p++;
155        } while (dummy);
156    }
157    put_user((unsigned long) NULL, envp);
158    current->mm->env_end = (unsigned long) p;
159    return (unsigned long)sp;
160}
161
162/****************************************************************************/
163
164#ifdef CONFIG_BINFMT_ZFLAT
165
166#include <linux/zlib.h>
167
168#define LBUFSIZE 4000
169
170/* gzip flag byte */
171#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
172#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
173#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
174#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
175#define COMMENT 0x10 /* bit 4 set: file comment present */
176#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
177#define RESERVED 0xC0 /* bit 6,7: reserved */
178
179static int decompress_exec(
180    struct linux_binprm *bprm,
181    unsigned long offset,
182    char *dst,
183    long len,
184    int fd)
185{
186    unsigned char *buf;
187    z_stream strm;
188    loff_t fpos;
189    int ret, retval;
190
191    DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
192
193    memset(&strm, 0, sizeof(strm));
194    strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
195    if (strm.workspace == NULL) {
196        DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
197        return -ENOMEM;
198    }
199    buf = kmalloc(LBUFSIZE, GFP_KERNEL);
200    if (buf == NULL) {
201        DBG_FLT("binfmt_flat: no memory for read buffer\n");
202        retval = -ENOMEM;
203        goto out_free;
204    }
205
206    /* Read in first chunk of data and parse gzip header. */
207    fpos = offset;
208    ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
209
210    strm.next_in = buf;
211    strm.avail_in = ret;
212    strm.total_in = 0;
213
214    retval = -ENOEXEC;
215
216    /* Check minimum size -- gzip header */
217    if (ret < 10) {
218        DBG_FLT("binfmt_flat: file too small?\n");
219        goto out_free_buf;
220    }
221
222    /* Check gzip magic number */
223    if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
224        DBG_FLT("binfmt_flat: unknown compression magic?\n");
225        goto out_free_buf;
226    }
227
228    /* Check gzip method */
229    if (buf[2] != 8) {
230        DBG_FLT("binfmt_flat: unknown compression method?\n");
231        goto out_free_buf;
232    }
233    /* Check gzip flags */
234    if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
235        (buf[3] & RESERVED)) {
236        DBG_FLT("binfmt_flat: unknown flags?\n");
237        goto out_free_buf;
238    }
239
240    ret = 10;
241    if (buf[3] & EXTRA_FIELD) {
242        ret += 2 + buf[10] + (buf[11] << 8);
243        if (unlikely(LBUFSIZE <= ret)) {
244            DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
245            goto out_free_buf;
246        }
247    }
248    if (buf[3] & ORIG_NAME) {
249        while (ret < LBUFSIZE && buf[ret++] != 0)
250            ;
251        if (unlikely(LBUFSIZE == ret)) {
252            DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
253            goto out_free_buf;
254        }
255    }
256    if (buf[3] & COMMENT) {
257        while (ret < LBUFSIZE && buf[ret++] != 0)
258            ;
259        if (unlikely(LBUFSIZE == ret)) {
260            DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
261            goto out_free_buf;
262        }
263    }
264
265    strm.next_in += ret;
266    strm.avail_in -= ret;
267
268    strm.next_out = dst;
269    strm.avail_out = len;
270    strm.total_out = 0;
271
272    if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
273        DBG_FLT("binfmt_flat: zlib init failed?\n");
274        goto out_free_buf;
275    }
276
277    while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
278        ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
279        if (ret <= 0)
280            break;
281        len -= ret;
282
283        strm.next_in = buf;
284        strm.avail_in = ret;
285        strm.total_in = 0;
286    }
287
288    if (ret < 0) {
289        DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
290            ret, strm.msg);
291        goto out_zlib;
292    }
293
294    retval = 0;
295out_zlib:
296    zlib_inflateEnd(&strm);
297out_free_buf:
298    kfree(buf);
299out_free:
300    kfree(strm.workspace);
301    return retval;
302}
303
304#endif /* CONFIG_BINFMT_ZFLAT */
305
306/****************************************************************************/
307
308static unsigned long
309calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
310{
311    unsigned long addr;
312    int id;
313    unsigned long start_brk;
314    unsigned long start_data;
315    unsigned long text_len;
316    unsigned long start_code;
317
318#ifdef CONFIG_BINFMT_SHARED_FLAT
319    if (r == 0)
320        id = curid; /* Relocs of 0 are always self referring */
321    else {
322        id = (r >> 24) & 0xff; /* Find ID for this reloc */
323        r &= 0x00ffffff; /* Trim ID off here */
324    }
325    if (id >= MAX_SHARED_LIBS) {
326        printk("BINFMT_FLAT: reference 0x%x to shared library %d",
327                (unsigned) r, id);
328        goto failed;
329    }
330    if (curid != id) {
331        if (internalp) {
332            printk("BINFMT_FLAT: reloc address 0x%x not in same module "
333                    "(%d != %d)", (unsigned) r, curid, id);
334            goto failed;
335        } else if ( ! p->lib_list[id].loaded &&
336                IS_ERR_VALUE(load_flat_shared_library(id, p))) {
337            printk("BINFMT_FLAT: failed to load library %d", id);
338            goto failed;
339        }
340        /* Check versioning information (i.e. time stamps) */
341        if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
342                p->lib_list[curid].build_date < p->lib_list[id].build_date) {
343            printk("BINFMT_FLAT: library %d is younger than %d", id, curid);
344            goto failed;
345        }
346    }
347#else
348    id = 0;
349#endif
350
351    start_brk = p->lib_list[id].start_brk;
352    start_data = p->lib_list[id].start_data;
353    start_code = p->lib_list[id].start_code;
354    text_len = p->lib_list[id].text_len;
355
356    if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
357        printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)",
358               (int) r,(int)(start_brk-start_code),(int)text_len);
359        goto failed;
360    }
361
362    if (r < text_len) /* In text segment */
363        addr = r + start_code;
364    else /* In data segment */
365        addr = r - text_len + start_data;
366
367    /* Range checked already above so doing the range tests is redundant...*/
368    return(addr);
369
370failed:
371    printk(", killing %s!\n", current->comm);
372    send_sig(SIGSEGV, current, 0);
373
374    return RELOC_FAILED;
375}
376
377/****************************************************************************/
378
379void old_reloc(unsigned long rl)
380{
381#ifdef DEBUG
382    char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
383#endif
384    flat_v2_reloc_t r;
385    unsigned long *ptr;
386    
387    r.value = rl;
388#if defined(CONFIG_COLDFIRE)
389    ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
390#else
391    ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
392#endif
393
394#ifdef DEBUG
395    printk("Relocation of variable at DATASEG+%x "
396        "(address %p, currently %x) into segment %s\n",
397        r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
398#endif
399    
400    switch (r.reloc.type) {
401    case OLD_FLAT_RELOC_TYPE_TEXT:
402        *ptr += current->mm->start_code;
403        break;
404    case OLD_FLAT_RELOC_TYPE_DATA:
405        *ptr += current->mm->start_data;
406        break;
407    case OLD_FLAT_RELOC_TYPE_BSS:
408        *ptr += current->mm->end_data;
409        break;
410    default:
411        printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
412        break;
413    }
414
415#ifdef DEBUG
416    printk("Relocation became %x\n", (int)*ptr);
417#endif
418}
419
420/****************************************************************************/
421
422static int load_flat_file(struct linux_binprm * bprm,
423        struct lib_info *libinfo, int id, unsigned long *extra_stack)
424{
425    struct flat_hdr * hdr;
426    unsigned long textpos = 0, datapos = 0, result;
427    unsigned long realdatastart = 0;
428    unsigned long text_len, data_len, bss_len, stack_len, flags;
429    unsigned long len, memp = 0;
430    unsigned long memp_size, extra, rlim;
431    unsigned long *reloc = 0, *rp;
432    struct inode *inode;
433    int i, rev, relocs = 0;
434    loff_t fpos;
435    unsigned long start_code, end_code;
436    int ret;
437
438    hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
439    inode = bprm->file->f_path.dentry->d_inode;
440
441    text_len = ntohl(hdr->data_start);
442    data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
443    bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
444    stack_len = ntohl(hdr->stack_size);
445    if (extra_stack) {
446        stack_len += *extra_stack;
447        *extra_stack = stack_len;
448    }
449    relocs = ntohl(hdr->reloc_count);
450    flags = ntohl(hdr->flags);
451    rev = ntohl(hdr->rev);
452
453    if (strncmp(hdr->magic, "bFLT", 4)) {
454        /*
455         * Previously, here was a printk to tell people
456         * "BINFMT_FLAT: bad header magic".
457         * But for the kernel which also use ELF FD-PIC format, this
458         * error message is confusing.
459         * because a lot of people do not manage to produce good
460         */
461        ret = -ENOEXEC;
462        goto err;
463    }
464
465    if (flags & FLAT_FLAG_KTRACE)
466        printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
467
468    if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
469        printk("BINFMT_FLAT: bad flat file version 0x%x (supported "
470            "0x%lx and 0x%lx)\n",
471            rev, FLAT_VERSION, OLD_FLAT_VERSION);
472        ret = -ENOEXEC;
473        goto err;
474    }
475    
476    /* Don't allow old format executables to use shared libraries */
477    if (rev == OLD_FLAT_VERSION && id != 0) {
478        printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n",
479                (int) FLAT_VERSION);
480        ret = -ENOEXEC;
481        goto err;
482    }
483
484    /*
485     * fix up the flags for the older format, there were all kinds
486     * of endian hacks, this only works for the simple cases
487     */
488    if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
489        flags = FLAT_FLAG_RAM;
490
491#ifndef CONFIG_BINFMT_ZFLAT
492    if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
493        printk("Support for ZFLAT executables is not enabled.\n");
494        ret = -ENOEXEC;
495        goto err;
496    }
497#endif
498
499    /*
500     * Check initial limits. This avoids letting people circumvent
501     * size limits imposed on them by creating programs with large
502     * arrays in the data or bss.
503     */
504    rlim = rlimit(RLIMIT_DATA);
505    if (rlim >= RLIM_INFINITY)
506        rlim = ~0;
507    if (data_len + bss_len > rlim) {
508        ret = -ENOMEM;
509        goto err;
510    }
511
512    /* Flush all traces of the currently running executable */
513    if (id == 0) {
514        result = flush_old_exec(bprm);
515        if (result) {
516            ret = result;
517            goto err;
518        }
519
520        /* OK, This is the point of no return */
521        set_personality(PER_LINUX_32BIT);
522        setup_new_exec(bprm);
523    }
524
525    /*
526     * calculate the extra space we need to map in
527     */
528    extra = max_t(unsigned long, bss_len + stack_len,
529            relocs * sizeof(unsigned long));
530
531    /*
532     * there are a couple of cases here, the separate code/data
533     * case, and then the fully copied to RAM case which lumps
534     * it all together.
535     */
536    if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
537        /*
538         * this should give us a ROM ptr, but if it doesn't we don't
539         * really care
540         */
541        DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
542
543        down_write(&current->mm->mmap_sem);
544        textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
545                  MAP_PRIVATE|MAP_EXECUTABLE, 0);
546        up_write(&current->mm->mmap_sem);
547        if (!textpos || IS_ERR_VALUE(textpos)) {
548            if (!textpos)
549                textpos = (unsigned long) -ENOMEM;
550            printk("Unable to mmap process text, errno %d\n", (int)-textpos);
551            ret = textpos;
552            goto err;
553        }
554
555        len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
556        len = PAGE_ALIGN(len);
557        down_write(&current->mm->mmap_sem);
558        realdatastart = do_mmap(0, 0, len,
559            PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
560        up_write(&current->mm->mmap_sem);
561
562        if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
563            if (!realdatastart)
564                realdatastart = (unsigned long) -ENOMEM;
565            printk("Unable to allocate RAM for process data, errno %d\n",
566                    (int)-realdatastart);
567            do_munmap(current->mm, textpos, text_len);
568            ret = realdatastart;
569            goto err;
570        }
571        datapos = ALIGN(realdatastart +
572                MAX_SHARED_LIBS * sizeof(unsigned long),
573                FLAT_DATA_ALIGN);
574
575        DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
576                (int)(data_len + bss_len + stack_len), (int)datapos);
577
578        fpos = ntohl(hdr->data_start);
579#ifdef CONFIG_BINFMT_ZFLAT
580        if (flags & FLAT_FLAG_GZDATA) {
581            result = decompress_exec(bprm, fpos, (char *) datapos,
582                         data_len + (relocs * sizeof(unsigned long)), 0);
583        } else
584#endif
585        {
586            result = bprm->file->f_op->read(bprm->file, (char *) datapos,
587                    data_len + (relocs * sizeof(unsigned long)), &fpos);
588        }
589        if (IS_ERR_VALUE(result)) {
590            printk("Unable to read data+bss, errno %d\n", (int)-result);
591            do_munmap(current->mm, textpos, text_len);
592            do_munmap(current->mm, realdatastart, data_len + extra);
593            ret = result;
594            goto err;
595        }
596
597        reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
598        memp = realdatastart;
599        memp_size = len;
600    } else {
601
602        len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
603        len = PAGE_ALIGN(len);
604        down_write(&current->mm->mmap_sem);
605        textpos = do_mmap(0, 0, len,
606            PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
607        up_write(&current->mm->mmap_sem);
608
609        if (!textpos || IS_ERR_VALUE(textpos)) {
610            if (!textpos)
611                textpos = (unsigned long) -ENOMEM;
612            printk("Unable to allocate RAM for process text/data, errno %d\n",
613                    (int)-textpos);
614            ret = textpos;
615            goto err;
616        }
617
618        realdatastart = textpos + ntohl(hdr->data_start);
619        datapos = ALIGN(realdatastart +
620                MAX_SHARED_LIBS * sizeof(unsigned long),
621                FLAT_DATA_ALIGN);
622
623        reloc = (unsigned long *)
624            (datapos + (ntohl(hdr->reloc_start) - text_len));
625        memp = textpos;
626        memp_size = len;
627#ifdef CONFIG_BINFMT_ZFLAT
628        /*
629         * load it all in and treat it like a RAM load from now on
630         */
631        if (flags & FLAT_FLAG_GZIP) {
632            result = decompress_exec(bprm, sizeof (struct flat_hdr),
633                     (((char *) textpos) + sizeof (struct flat_hdr)),
634                     (text_len + data_len + (relocs * sizeof(unsigned long))
635                          - sizeof (struct flat_hdr)),
636                     0);
637            memmove((void *) datapos, (void *) realdatastart,
638                    data_len + (relocs * sizeof(unsigned long)));
639        } else if (flags & FLAT_FLAG_GZDATA) {
640            fpos = 0;
641            result = bprm->file->f_op->read(bprm->file,
642                    (char *) textpos, text_len, &fpos);
643            if (!IS_ERR_VALUE(result))
644                result = decompress_exec(bprm, text_len, (char *) datapos,
645                         data_len + (relocs * sizeof(unsigned long)), 0);
646        }
647        else
648#endif
649        {
650            fpos = 0;
651            result = bprm->file->f_op->read(bprm->file,
652                    (char *) textpos, text_len, &fpos);
653            if (!IS_ERR_VALUE(result)) {
654                fpos = ntohl(hdr->data_start);
655                result = bprm->file->f_op->read(bprm->file, (char *) datapos,
656                    data_len + (relocs * sizeof(unsigned long)), &fpos);
657            }
658        }
659        if (IS_ERR_VALUE(result)) {
660            printk("Unable to read code+data+bss, errno %d\n",(int)-result);
661            do_munmap(current->mm, textpos, text_len + data_len + extra +
662                MAX_SHARED_LIBS * sizeof(unsigned long));
663            ret = result;
664            goto err;
665        }
666    }
667
668    if (flags & FLAT_FLAG_KTRACE)
669        printk("Mapping is %x, Entry point is %x, data_start is %x\n",
670            (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
671
672    /* The main program needs a little extra setup in the task structure */
673    start_code = textpos + sizeof (struct flat_hdr);
674    end_code = textpos + text_len;
675    if (id == 0) {
676        current->mm->start_code = start_code;
677        current->mm->end_code = end_code;
678        current->mm->start_data = datapos;
679        current->mm->end_data = datapos + data_len;
680        /*
681         * set up the brk stuff, uses any slack left in data/bss/stack
682         * allocation. We put the brk after the bss (between the bss
683         * and stack) like other platforms.
684         * Userspace code relies on the stack pointer starting out at
685         * an address right at the end of a page.
686         */
687        current->mm->start_brk = datapos + data_len + bss_len;
688        current->mm->brk = (current->mm->start_brk + 3) & ~3;
689        current->mm->context.end_brk = memp + memp_size - stack_len;
690    }
691
692    if (flags & FLAT_FLAG_KTRACE)
693        printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
694            id ? "Lib" : "Load", bprm->filename,
695            (int) start_code, (int) end_code,
696            (int) datapos,
697            (int) (datapos + data_len),
698            (int) (datapos + data_len),
699            (int) (((datapos + data_len + bss_len) + 3) & ~3));
700
701    text_len -= sizeof(struct flat_hdr); /* the real code len */
702
703    /* Store the current module values into the global library structure */
704    libinfo->lib_list[id].start_code = start_code;
705    libinfo->lib_list[id].start_data = datapos;
706    libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
707    libinfo->lib_list[id].text_len = text_len;
708    libinfo->lib_list[id].loaded = 1;
709    libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
710    libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
711    
712    /*
713     * We just load the allocations into some temporary memory to
714     * help simplify all this mumbo jumbo
715     *
716     * We've got two different sections of relocation entries.
717     * The first is the GOT which resides at the begining of the data segment
718     * and is terminated with a -1. This one can be relocated in place.
719     * The second is the extra relocation entries tacked after the image's
720     * data segment. These require a little more processing as the entry is
721     * really an offset into the image which contains an offset into the
722     * image.
723     */
724    if (flags & FLAT_FLAG_GOTPIC) {
725        for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
726            unsigned long addr;
727            if (*rp) {
728                addr = calc_reloc(*rp, libinfo, id, 0);
729                if (addr == RELOC_FAILED) {
730                    ret = -ENOEXEC;
731                    goto err;
732                }
733                *rp = addr;
734            }
735        }
736    }
737
738    /*
739     * Now run through the relocation entries.
740     * We've got to be careful here as C++ produces relocatable zero
741     * entries in the constructor and destructor tables which are then
742     * tested for being not zero (which will always occur unless we're
743     * based from address zero). This causes an endless loop as __start
744     * is at zero. The solution used is to not relocate zero addresses.
745     * This has the negative side effect of not allowing a global data
746     * reference to be statically initialised to _stext (I've moved
747     * __start to address 4 so that is okay).
748     */
749    if (rev > OLD_FLAT_VERSION) {
750        unsigned long persistent = 0;
751        for (i=0; i < relocs; i++) {
752            unsigned long addr, relval;
753
754            /* Get the address of the pointer to be
755               relocated (of course, the address has to be
756               relocated first). */
757            relval = ntohl(reloc[i]);
758            if (flat_set_persistent (relval, &persistent))
759                continue;
760            addr = flat_get_relocate_addr(relval);
761            rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
762            if (rp == (unsigned long *)RELOC_FAILED) {
763                ret = -ENOEXEC;
764                goto err;
765            }
766
767            /* Get the pointer's value. */
768            addr = flat_get_addr_from_rp(rp, relval, flags,
769                            &persistent);
770            if (addr != 0) {
771                /*
772                 * Do the relocation. PIC relocs in the data section are
773                 * already in target order
774                 */
775                if ((flags & FLAT_FLAG_GOTPIC) == 0)
776                    addr = ntohl(addr);
777                addr = calc_reloc(addr, libinfo, id, 0);
778                if (addr == RELOC_FAILED) {
779                    ret = -ENOEXEC;
780                    goto err;
781                }
782
783                /* Write back the relocated pointer. */
784                flat_put_addr_at_rp(rp, addr, relval);
785            }
786        }
787    } else {
788        for (i=0; i < relocs; i++)
789            old_reloc(ntohl(reloc[i]));
790    }
791    
792    flush_icache_range(start_code, end_code);
793
794    /* zero the BSS, BRK and stack areas */
795    memset((void*)(datapos + data_len), 0, bss_len +
796            (memp + memp_size - stack_len - /* end brk */
797            libinfo->lib_list[id].start_brk) + /* start brk */
798            stack_len);
799
800    return 0;
801err:
802    return ret;
803}
804
805
806/****************************************************************************/
807#ifdef CONFIG_BINFMT_SHARED_FLAT
808
809/*
810 * Load a shared library into memory. The library gets its own data
811 * segment (including bss) but not argv/argc/environ.
812 */
813
814static int load_flat_shared_library(int id, struct lib_info *libs)
815{
816    struct linux_binprm bprm;
817    int res;
818    char buf[16];
819
820    /* Create the file name */
821    sprintf(buf, "/lib/lib%d.so", id);
822
823    /* Open the file up */
824    bprm.filename = buf;
825    bprm.file = open_exec(bprm.filename);
826    res = PTR_ERR(bprm.file);
827    if (IS_ERR(bprm.file))
828        return res;
829
830    bprm.cred = prepare_exec_creds();
831    res = -ENOMEM;
832    if (!bprm.cred)
833        goto out;
834
835    res = prepare_binprm(&bprm);
836
837    if (!IS_ERR_VALUE(res))
838        res = load_flat_file(&bprm, libs, id, NULL);
839
840    abort_creds(bprm.cred);
841
842out:
843    allow_write_access(bprm.file);
844    fput(bprm.file);
845
846    return(res);
847}
848
849#endif /* CONFIG_BINFMT_SHARED_FLAT */
850/****************************************************************************/
851
852/*
853 * These are the functions used to load flat style executables and shared
854 * libraries. There is no binary dependent code anywhere else.
855 */
856
857static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
858{
859    struct lib_info libinfo;
860    unsigned long p = bprm->p;
861    unsigned long stack_len;
862    unsigned long start_addr;
863    unsigned long *sp;
864    int res;
865    int i, j;
866
867    memset(&libinfo, 0, sizeof(libinfo));
868    /*
869     * We have to add the size of our arguments to our stack size
870     * otherwise it's too easy for users to create stack overflows
871     * by passing in a huge argument list. And yes, we have to be
872     * pedantic and include space for the argv/envp array as it may have
873     * a lot of entries.
874     */
875#define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
876    stack_len = TOP_OF_ARGS - bprm->p; /* the strings */
877    stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
878    stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
879    stack_len += FLAT_DATA_ALIGN - 1; /* reserve for upcoming alignment */
880    
881    res = load_flat_file(bprm, &libinfo, 0, &stack_len);
882    if (IS_ERR_VALUE(res))
883        return res;
884    
885    /* Update data segment pointers for all libraries */
886    for (i=0; i<MAX_SHARED_LIBS; i++)
887        if (libinfo.lib_list[i].loaded)
888            for (j=0; j<MAX_SHARED_LIBS; j++)
889                (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] =
890                    (libinfo.lib_list[j].loaded)?
891                        libinfo.lib_list[j].start_data:UNLOADED_LIB;
892
893    install_exec_creds(bprm);
894     current->flags &= ~PF_FORKNOEXEC;
895
896    set_binfmt(&flat_format);
897
898    p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
899    DBG_FLT("p=%x\n", (int)p);
900
901    /* copy the arg pages onto the stack, this could be more efficient :-) */
902    for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
903        * (char *) --p =
904            ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
905
906    sp = (unsigned long *) create_flat_tables(p, bprm);
907    
908    /* Fake some return addresses to ensure the call chain will
909     * initialise library in order for us. We are required to call
910     * lib 1 first, then 2, ... and finally the main program (id 0).
911     */
912    start_addr = libinfo.lib_list[0].entry;
913
914#ifdef CONFIG_BINFMT_SHARED_FLAT
915    for (i = MAX_SHARED_LIBS-1; i>0; i--) {
916        if (libinfo.lib_list[i].loaded) {
917            /* Push previos first to call address */
918            --sp; put_user(start_addr, sp);
919            start_addr = libinfo.lib_list[i].entry;
920        }
921    }
922#endif
923    
924    /* Stash our initial stack pointer into the mm structure */
925    current->mm->start_stack = (unsigned long )sp;
926
927#ifdef FLAT_PLAT_INIT
928    FLAT_PLAT_INIT(regs);
929#endif
930    DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
931        (int)regs, (int)start_addr, (int)current->mm->start_stack);
932    
933    start_thread(regs, start_addr, current->mm->start_stack);
934
935    return 0;
936}
937
938/****************************************************************************/
939
940static int __init init_flat_binfmt(void)
941{
942    return register_binfmt(&flat_format);
943}
944
945/****************************************************************************/
946
947core_initcall(init_flat_binfmt);
948
949/****************************************************************************/
950

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