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(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
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(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
106{
107    printk("Process %s:%d received signr %d and should have core dumped\n",
108            current->comm, current->pid, (int) 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        if (ret >= (unsigned long) -4096)
282            break;
283        len -= ret;
284
285        strm.next_in = buf;
286        strm.avail_in = ret;
287        strm.total_in = 0;
288    }
289
290    if (ret < 0) {
291        DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
292            ret, strm.msg);
293        goto out_zlib;
294    }
295
296    retval = 0;
297out_zlib:
298    zlib_inflateEnd(&strm);
299out_free_buf:
300    kfree(buf);
301out_free:
302    kfree(strm.workspace);
303    return retval;
304}
305
306#endif /* CONFIG_BINFMT_ZFLAT */
307
308/****************************************************************************/
309
310static unsigned long
311calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
312{
313    unsigned long addr;
314    int id;
315    unsigned long start_brk;
316    unsigned long start_data;
317    unsigned long text_len;
318    unsigned long start_code;
319
320#ifdef CONFIG_BINFMT_SHARED_FLAT
321    if (r == 0)
322        id = curid; /* Relocs of 0 are always self referring */
323    else {
324        id = (r >> 24) & 0xff; /* Find ID for this reloc */
325        r &= 0x00ffffff; /* Trim ID off here */
326    }
327    if (id >= MAX_SHARED_LIBS) {
328        printk("BINFMT_FLAT: reference 0x%x to shared library %d",
329                (unsigned) r, id);
330        goto failed;
331    }
332    if (curid != id) {
333        if (internalp) {
334            printk("BINFMT_FLAT: reloc address 0x%x not in same module "
335                    "(%d != %d)", (unsigned) r, curid, id);
336            goto failed;
337        } else if ( ! p->lib_list[id].loaded &&
338                load_flat_shared_library(id, p) > (unsigned long) -4096) {
339            printk("BINFMT_FLAT: failed to load library %d", id);
340            goto failed;
341        }
342        /* Check versioning information (i.e. time stamps) */
343        if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
344                p->lib_list[curid].build_date < p->lib_list[id].build_date) {
345            printk("BINFMT_FLAT: library %d is younger than %d", id, curid);
346            goto failed;
347        }
348    }
349#else
350    id = 0;
351#endif
352
353    start_brk = p->lib_list[id].start_brk;
354    start_data = p->lib_list[id].start_data;
355    start_code = p->lib_list[id].start_code;
356    text_len = p->lib_list[id].text_len;
357
358    if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
359        printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)",
360               (int) r,(int)(start_brk-start_code),(int)text_len);
361        goto failed;
362    }
363
364    if (r < text_len) /* In text segment */
365        addr = r + start_code;
366    else /* In data segment */
367        addr = r - text_len + start_data;
368
369    /* Range checked already above so doing the range tests is redundant...*/
370    return(addr);
371
372failed:
373    printk(", killing %s!\n", current->comm);
374    send_sig(SIGSEGV, current, 0);
375
376    return RELOC_FAILED;
377}
378
379/****************************************************************************/
380
381void old_reloc(unsigned long rl)
382{
383#ifdef DEBUG
384    char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
385#endif
386    flat_v2_reloc_t r;
387    unsigned long *ptr;
388    
389    r.value = rl;
390#if defined(CONFIG_COLDFIRE)
391    ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
392#else
393    ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
394#endif
395
396#ifdef DEBUG
397    printk("Relocation of variable at DATASEG+%x "
398        "(address %p, currently %x) into segment %s\n",
399        r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
400#endif
401    
402    switch (r.reloc.type) {
403    case OLD_FLAT_RELOC_TYPE_TEXT:
404        *ptr += current->mm->start_code;
405        break;
406    case OLD_FLAT_RELOC_TYPE_DATA:
407        *ptr += current->mm->start_data;
408        break;
409    case OLD_FLAT_RELOC_TYPE_BSS:
410        *ptr += current->mm->end_data;
411        break;
412    default:
413        printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
414        break;
415    }
416
417#ifdef DEBUG
418    printk("Relocation became %x\n", (int)*ptr);
419#endif
420}
421
422/****************************************************************************/
423
424static int load_flat_file(struct linux_binprm * bprm,
425        struct lib_info *libinfo, int id, unsigned long *extra_stack)
426{
427    struct flat_hdr * hdr;
428    unsigned long textpos = 0, datapos = 0, result;
429    unsigned long realdatastart = 0;
430    unsigned long text_len, data_len, bss_len, stack_len, flags;
431    unsigned long len, memp = 0;
432    unsigned long memp_size, extra, rlim;
433    unsigned long *reloc = 0, *rp;
434    struct inode *inode;
435    int i, rev, relocs = 0;
436    loff_t fpos;
437    unsigned long start_code, end_code;
438    int ret;
439
440    hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
441    inode = bprm->file->f_path.dentry->d_inode;
442
443    text_len = ntohl(hdr->data_start);
444    data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
445    bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
446    stack_len = ntohl(hdr->stack_size);
447    if (extra_stack) {
448        stack_len += *extra_stack;
449        *extra_stack = stack_len;
450    }
451    relocs = ntohl(hdr->reloc_count);
452    flags = ntohl(hdr->flags);
453    rev = ntohl(hdr->rev);
454
455    if (strncmp(hdr->magic, "bFLT", 4)) {
456        /*
457         * Previously, here was a printk to tell people
458         * "BINFMT_FLAT: bad header magic".
459         * But for the kernel which also use ELF FD-PIC format, this
460         * error message is confusing.
461         * because a lot of people do not manage to produce good
462         */
463        ret = -ENOEXEC;
464        goto err;
465    }
466
467    if (flags & FLAT_FLAG_KTRACE)
468        printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
469
470    if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
471        printk("BINFMT_FLAT: bad flat file version 0x%x (supported "
472            "0x%lx and 0x%lx)\n",
473            rev, FLAT_VERSION, OLD_FLAT_VERSION);
474        ret = -ENOEXEC;
475        goto err;
476    }
477    
478    /* Don't allow old format executables to use shared libraries */
479    if (rev == OLD_FLAT_VERSION && id != 0) {
480        printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n",
481                (int) FLAT_VERSION);
482        ret = -ENOEXEC;
483        goto err;
484    }
485
486    /*
487     * fix up the flags for the older format, there were all kinds
488     * of endian hacks, this only works for the simple cases
489     */
490    if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
491        flags = FLAT_FLAG_RAM;
492
493#ifndef CONFIG_BINFMT_ZFLAT
494    if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
495        printk("Support for ZFLAT executables is not enabled.\n");
496        ret = -ENOEXEC;
497        goto err;
498    }
499#endif
500
501    /*
502     * Check initial limits. This avoids letting people circumvent
503     * size limits imposed on them by creating programs with large
504     * arrays in the data or bss.
505     */
506    rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
507    if (rlim >= RLIM_INFINITY)
508        rlim = ~0;
509    if (data_len + bss_len > rlim) {
510        ret = -ENOMEM;
511        goto err;
512    }
513
514    /* Flush all traces of the currently running executable */
515    if (id == 0) {
516        result = flush_old_exec(bprm);
517        if (result) {
518            ret = result;
519            goto err;
520        }
521
522        /* OK, This is the point of no return */
523        set_personality(PER_LINUX_32BIT);
524    }
525
526    /*
527     * calculate the extra space we need to map in
528     */
529    extra = max_t(unsigned long, bss_len + stack_len,
530            relocs * sizeof(unsigned long));
531
532    /*
533     * there are a couple of cases here, the separate code/data
534     * case, and then the fully copied to RAM case which lumps
535     * it all together.
536     */
537    if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
538        /*
539         * this should give us a ROM ptr, but if it doesn't we don't
540         * really care
541         */
542        DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
543
544        down_write(&current->mm->mmap_sem);
545        textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
546                  MAP_PRIVATE|MAP_EXECUTABLE, 0);
547        up_write(&current->mm->mmap_sem);
548        if (!textpos || textpos >= (unsigned long) -4096) {
549            if (!textpos)
550                textpos = (unsigned long) -ENOMEM;
551            printk("Unable to mmap process text, errno %d\n", (int)-textpos);
552            ret = textpos;
553            goto err;
554        }
555
556        len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
557        len = PAGE_ALIGN(len);
558        down_write(&current->mm->mmap_sem);
559        realdatastart = do_mmap(0, 0, len,
560            PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
561        up_write(&current->mm->mmap_sem);
562
563        if (realdatastart == 0 || realdatastart >= (unsigned long)-4096) {
564            if (!realdatastart)
565                realdatastart = (unsigned long) -ENOMEM;
566            printk("Unable to allocate RAM for process data, errno %d\n",
567                    (int)-realdatastart);
568            do_munmap(current->mm, textpos, text_len);
569            ret = realdatastart;
570            goto err;
571        }
572        datapos = ALIGN(realdatastart +
573                MAX_SHARED_LIBS * sizeof(unsigned long),
574                FLAT_DATA_ALIGN);
575
576        DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
577                (int)(data_len + bss_len + stack_len), (int)datapos);
578
579        fpos = ntohl(hdr->data_start);
580#ifdef CONFIG_BINFMT_ZFLAT
581        if (flags & FLAT_FLAG_GZDATA) {
582            result = decompress_exec(bprm, fpos, (char *) datapos,
583                         data_len + (relocs * sizeof(unsigned long)), 0);
584        } else
585#endif
586        {
587            result = bprm->file->f_op->read(bprm->file, (char *) datapos,
588                    data_len + (relocs * sizeof(unsigned long)), &fpos);
589        }
590        if (result >= (unsigned long)-4096) {
591            printk("Unable to read data+bss, errno %d\n", (int)-result);
592            do_munmap(current->mm, textpos, text_len);
593            do_munmap(current->mm, realdatastart, data_len + extra);
594            ret = result;
595            goto err;
596        }
597
598        reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
599        memp = realdatastart;
600        memp_size = len;
601    } else {
602
603        len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
604        len = PAGE_ALIGN(len);
605        down_write(&current->mm->mmap_sem);
606        textpos = do_mmap(0, 0, len,
607            PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
608        up_write(&current->mm->mmap_sem);
609
610        if (!textpos || textpos >= (unsigned long) -4096) {
611            if (!textpos)
612                textpos = (unsigned long) -ENOMEM;
613            printk("Unable to allocate RAM for process text/data, errno %d\n",
614                    (int)-textpos);
615            ret = textpos;
616            goto err;
617        }
618
619        realdatastart = textpos + ntohl(hdr->data_start);
620        datapos = ALIGN(realdatastart +
621                MAX_SHARED_LIBS * sizeof(unsigned long),
622                FLAT_DATA_ALIGN);
623
624        reloc = (unsigned long *)
625            (datapos + (ntohl(hdr->reloc_start) - text_len));
626        memp = textpos;
627        memp_size = len;
628#ifdef CONFIG_BINFMT_ZFLAT
629        /*
630         * load it all in and treat it like a RAM load from now on
631         */
632        if (flags & FLAT_FLAG_GZIP) {
633            result = decompress_exec(bprm, sizeof (struct flat_hdr),
634                     (((char *) textpos) + sizeof (struct flat_hdr)),
635                     (text_len + data_len + (relocs * sizeof(unsigned long))
636                          - sizeof (struct flat_hdr)),
637                     0);
638            memmove((void *) datapos, (void *) realdatastart,
639                    data_len + (relocs * sizeof(unsigned long)));
640        } else if (flags & FLAT_FLAG_GZDATA) {
641            fpos = 0;
642            result = bprm->file->f_op->read(bprm->file,
643                    (char *) textpos, text_len, &fpos);
644            if (result < (unsigned long) -4096)
645                result = decompress_exec(bprm, text_len, (char *) datapos,
646                         data_len + (relocs * sizeof(unsigned long)), 0);
647        }
648        else
649#endif
650        {
651            fpos = 0;
652            result = bprm->file->f_op->read(bprm->file,
653                    (char *) textpos, text_len, &fpos);
654            if (result < (unsigned long) -4096) {
655                fpos = ntohl(hdr->data_start);
656                result = bprm->file->f_op->read(bprm->file, (char *) datapos,
657                    data_len + (relocs * sizeof(unsigned long)), &fpos);
658            }
659        }
660        if (result >= (unsigned long)-4096) {
661            printk("Unable to read code+data+bss, errno %d\n",(int)-result);
662            do_munmap(current->mm, textpos, text_len + data_len + extra +
663                MAX_SHARED_LIBS * sizeof(unsigned long));
664            ret = result;
665            goto err;
666        }
667    }
668
669    if (flags & FLAT_FLAG_KTRACE)
670        printk("Mapping is %x, Entry point is %x, data_start is %x\n",
671            (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
672
673    /* The main program needs a little extra setup in the task structure */
674    start_code = textpos + sizeof (struct flat_hdr);
675    end_code = textpos + text_len;
676    if (id == 0) {
677        current->mm->start_code = start_code;
678        current->mm->end_code = end_code;
679        current->mm->start_data = datapos;
680        current->mm->end_data = datapos + data_len;
681        /*
682         * set up the brk stuff, uses any slack left in data/bss/stack
683         * allocation. We put the brk after the bss (between the bss
684         * and stack) like other platforms.
685         * Userspace code relies on the stack pointer starting out at
686         * an address right at the end of a page.
687         */
688        current->mm->start_brk = datapos + data_len + bss_len;
689        current->mm->brk = (current->mm->start_brk + 3) & ~3;
690        current->mm->context.end_brk = memp + memp_size - stack_len;
691    }
692
693    if (flags & FLAT_FLAG_KTRACE)
694        printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
695            id ? "Lib" : "Load", bprm->filename,
696            (int) start_code, (int) end_code,
697            (int) datapos,
698            (int) (datapos + data_len),
699            (int) (datapos + data_len),
700            (int) (((datapos + data_len + bss_len) + 3) & ~3));
701
702    text_len -= sizeof(struct flat_hdr); /* the real code len */
703
704    /* Store the current module values into the global library structure */
705    libinfo->lib_list[id].start_code = start_code;
706    libinfo->lib_list[id].start_data = datapos;
707    libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
708    libinfo->lib_list[id].text_len = text_len;
709    libinfo->lib_list[id].loaded = 1;
710    libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
711    libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
712    
713    /*
714     * We just load the allocations into some temporary memory to
715     * help simplify all this mumbo jumbo
716     *
717     * We've got two different sections of relocation entries.
718     * The first is the GOT which resides at the begining of the data segment
719     * and is terminated with a -1. This one can be relocated in place.
720     * The second is the extra relocation entries tacked after the image's
721     * data segment. These require a little more processing as the entry is
722     * really an offset into the image which contains an offset into the
723     * image.
724     */
725    if (flags & FLAT_FLAG_GOTPIC) {
726        for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
727            unsigned long addr;
728            if (*rp) {
729                addr = calc_reloc(*rp, libinfo, id, 0);
730                if (addr == RELOC_FAILED) {
731                    ret = -ENOEXEC;
732                    goto err;
733                }
734                *rp = addr;
735            }
736        }
737    }
738
739    /*
740     * Now run through the relocation entries.
741     * We've got to be careful here as C++ produces relocatable zero
742     * entries in the constructor and destructor tables which are then
743     * tested for being not zero (which will always occur unless we're
744     * based from address zero). This causes an endless loop as __start
745     * is at zero. The solution used is to not relocate zero addresses.
746     * This has the negative side effect of not allowing a global data
747     * reference to be statically initialised to _stext (I've moved
748     * __start to address 4 so that is okay).
749     */
750    if (rev > OLD_FLAT_VERSION) {
751        unsigned long persistent = 0;
752        for (i=0; i < relocs; i++) {
753            unsigned long addr, relval;
754
755            /* Get the address of the pointer to be
756               relocated (of course, the address has to be
757               relocated first). */
758            relval = ntohl(reloc[i]);
759            if (flat_set_persistent (relval, &persistent))
760                continue;
761            addr = flat_get_relocate_addr(relval);
762            rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
763            if (rp == (unsigned long *)RELOC_FAILED) {
764                ret = -ENOEXEC;
765                goto err;
766            }
767
768            /* Get the pointer's value. */
769            addr = flat_get_addr_from_rp(rp, relval, flags,
770                            &persistent);
771            if (addr != 0) {
772                /*
773                 * Do the relocation. PIC relocs in the data section are
774                 * already in target order
775                 */
776                if ((flags & FLAT_FLAG_GOTPIC) == 0)
777                    addr = ntohl(addr);
778                addr = calc_reloc(addr, libinfo, id, 0);
779                if (addr == RELOC_FAILED) {
780                    ret = -ENOEXEC;
781                    goto err;
782                }
783
784                /* Write back the relocated pointer. */
785                flat_put_addr_at_rp(rp, addr, relval);
786            }
787        }
788    } else {
789        for (i=0; i < relocs; i++)
790            old_reloc(ntohl(reloc[i]));
791    }
792    
793    flush_icache_range(start_code, end_code);
794
795    /* zero the BSS, BRK and stack areas */
796    memset((void*)(datapos + data_len), 0, bss_len +
797            (memp + memp_size - stack_len - /* end brk */
798            libinfo->lib_list[id].start_brk) + /* start brk */
799            stack_len);
800
801    return 0;
802err:
803    return ret;
804}
805
806
807/****************************************************************************/
808#ifdef CONFIG_BINFMT_SHARED_FLAT
809
810/*
811 * Load a shared library into memory. The library gets its own data
812 * segment (including bss) but not argv/argc/environ.
813 */
814
815static int load_flat_shared_library(int id, struct lib_info *libs)
816{
817    struct linux_binprm bprm;
818    int res;
819    char buf[16];
820
821    /* Create the file name */
822    sprintf(buf, "/lib/lib%d.so", id);
823
824    /* Open the file up */
825    bprm.filename = buf;
826    bprm.file = open_exec(bprm.filename);
827    res = PTR_ERR(bprm.file);
828    if (IS_ERR(bprm.file))
829        return res;
830
831    bprm.cred = prepare_exec_creds();
832    res = -ENOMEM;
833    if (!bprm.cred)
834        goto out;
835
836    res = prepare_binprm(&bprm);
837
838    if (res <= (unsigned long)-4096)
839        res = load_flat_file(&bprm, libs, id, NULL);
840
841    abort_creds(bprm.cred);
842
843out:
844    allow_write_access(bprm.file);
845    fput(bprm.file);
846
847    return(res);
848}
849
850#endif /* CONFIG_BINFMT_SHARED_FLAT */
851/****************************************************************************/
852
853/*
854 * These are the functions used to load flat style executables and shared
855 * libraries. There is no binary dependent code anywhere else.
856 */
857
858static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
859{
860    struct lib_info libinfo;
861    unsigned long p = bprm->p;
862    unsigned long stack_len;
863    unsigned long start_addr;
864    unsigned long *sp;
865    int res;
866    int i, j;
867
868    memset(&libinfo, 0, sizeof(libinfo));
869    /*
870     * We have to add the size of our arguments to our stack size
871     * otherwise it's too easy for users to create stack overflows
872     * by passing in a huge argument list. And yes, we have to be
873     * pedantic and include space for the argv/envp array as it may have
874     * a lot of entries.
875     */
876#define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
877    stack_len = TOP_OF_ARGS - bprm->p; /* the strings */
878    stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
879    stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
880    stack_len += FLAT_DATA_ALIGN - 1; /* reserve for upcoming alignment */
881    
882    res = load_flat_file(bprm, &libinfo, 0, &stack_len);
883    if (res > (unsigned long)-4096)
884        return res;
885    
886    /* Update data segment pointers for all libraries */
887    for (i=0; i<MAX_SHARED_LIBS; i++)
888        if (libinfo.lib_list[i].loaded)
889            for (j=0; j<MAX_SHARED_LIBS; j++)
890                (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] =
891                    (libinfo.lib_list[j].loaded)?
892                        libinfo.lib_list[j].start_data:UNLOADED_LIB;
893
894    install_exec_creds(bprm);
895     current->flags &= ~PF_FORKNOEXEC;
896
897    set_binfmt(&flat_format);
898
899    p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
900    DBG_FLT("p=%x\n", (int)p);
901
902    /* copy the arg pages onto the stack, this could be more efficient :-) */
903    for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
904        * (char *) --p =
905            ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
906
907    sp = (unsigned long *) create_flat_tables(p, bprm);
908    
909    /* Fake some return addresses to ensure the call chain will
910     * initialise library in order for us. We are required to call
911     * lib 1 first, then 2, ... and finally the main program (id 0).
912     */
913    start_addr = libinfo.lib_list[0].entry;
914
915#ifdef CONFIG_BINFMT_SHARED_FLAT
916    for (i = MAX_SHARED_LIBS-1; i>0; i--) {
917        if (libinfo.lib_list[i].loaded) {
918            /* Push previos first to call address */
919            --sp; put_user(start_addr, sp);
920            start_addr = libinfo.lib_list[i].entry;
921        }
922    }
923#endif
924    
925    /* Stash our initial stack pointer into the mm structure */
926    current->mm->start_stack = (unsigned long )sp;
927
928#ifdef FLAT_PLAT_INIT
929    FLAT_PLAT_INIT(regs);
930#endif
931    DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
932        (int)regs, (int)start_addr, (int)current->mm->start_stack);
933    
934    start_thread(regs, start_addr, current->mm->start_stack);
935
936    return 0;
937}
938
939/****************************************************************************/
940
941static int __init init_flat_binfmt(void)
942{
943    return register_binfmt(&flat_format);
944}
945
946/****************************************************************************/
947
948core_initcall(init_flat_binfmt);
949
950/****************************************************************************/
951

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