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 (data section and bss) needs to be aligned.
60 * We pick 0x20 here because it is the max value elf2flt has always
61 * used in producing FLAT files, and because it seems to be large
62 * enough to make all the gcc alignment related tests happy.
63 */
64#define FLAT_DATA_ALIGN (0x20)
65
66/*
67 * User data (stack) also needs to be aligned.
68 * Here we can be a bit looser than the data sections since this
69 * needs to only meet arch ABI requirements.
70 */
71#define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
72
73#define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
74#define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */
75
76struct lib_info {
77    struct {
78        unsigned long start_code; /* Start of text segment */
79        unsigned long start_data; /* Start of data segment */
80        unsigned long start_brk; /* End of data segment */
81        unsigned long text_len; /* Length of text segment */
82        unsigned long entry; /* Start address for this module */
83        unsigned long build_date; /* When this one was compiled */
84        short loaded; /* Has this library been loaded? */
85    } lib_list[MAX_SHARED_LIBS];
86};
87
88#ifdef CONFIG_BINFMT_SHARED_FLAT
89static int load_flat_shared_library(int id, struct lib_info *p);
90#endif
91
92static int load_flat_binary(struct linux_binprm *, struct pt_regs * regs);
93static int flat_core_dump(struct coredump_params *cprm);
94
95static struct linux_binfmt flat_format = {
96    .module = THIS_MODULE,
97    .load_binary = load_flat_binary,
98    .core_dump = flat_core_dump,
99    .min_coredump = PAGE_SIZE
100};
101
102/****************************************************************************/
103/*
104 * Routine writes a core dump image in the current directory.
105 * Currently only a stub-function.
106 */
107
108static int flat_core_dump(struct coredump_params *cprm)
109{
110    printk("Process %s:%d received signr %d and should have core dumped\n",
111            current->comm, current->pid, (int) cprm->signr);
112    return(1);
113}
114
115/****************************************************************************/
116/*
117 * create_flat_tables() parses the env- and arg-strings in new user
118 * memory and creates the pointer tables from them, and puts their
119 * addresses on the "stack", returning the new stack pointer value.
120 */
121
122static unsigned long create_flat_tables(
123    unsigned long pp,
124    struct linux_binprm * bprm)
125{
126    unsigned long *argv,*envp;
127    unsigned long * sp;
128    char * p = (char*)pp;
129    int argc = bprm->argc;
130    int envc = bprm->envc;
131    char uninitialized_var(dummy);
132
133    sp = (unsigned long *)p;
134    sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
135    sp = (unsigned long *) ((unsigned long)sp & -FLAT_STACK_ALIGN);
136    argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
137    envp = argv + (argc + 1);
138
139    if (flat_argvp_envp_on_stack()) {
140        put_user((unsigned long) envp, sp + 2);
141        put_user((unsigned long) argv, sp + 1);
142    }
143
144    put_user(argc, sp);
145    current->mm->arg_start = (unsigned long) p;
146    while (argc-->0) {
147        put_user((unsigned long) p, argv++);
148        do {
149            get_user(dummy, p); p++;
150        } while (dummy);
151    }
152    put_user((unsigned long) NULL, argv);
153    current->mm->arg_end = current->mm->env_start = (unsigned long) p;
154    while (envc-->0) {
155        put_user((unsigned long)p, envp); envp++;
156        do {
157            get_user(dummy, p); p++;
158        } while (dummy);
159    }
160    put_user((unsigned long) NULL, envp);
161    current->mm->env_end = (unsigned long) p;
162    return (unsigned long)sp;
163}
164
165/****************************************************************************/
166
167#ifdef CONFIG_BINFMT_ZFLAT
168
169#include <linux/zlib.h>
170
171#define LBUFSIZE 4000
172
173/* gzip flag byte */
174#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
175#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
176#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
177#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
178#define COMMENT 0x10 /* bit 4 set: file comment present */
179#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
180#define RESERVED 0xC0 /* bit 6,7: reserved */
181
182static int decompress_exec(
183    struct linux_binprm *bprm,
184    unsigned long offset,
185    char *dst,
186    long len,
187    int fd)
188{
189    unsigned char *buf;
190    z_stream strm;
191    loff_t fpos;
192    int ret, retval;
193
194    DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
195
196    memset(&strm, 0, sizeof(strm));
197    strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
198    if (strm.workspace == NULL) {
199        DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
200        return -ENOMEM;
201    }
202    buf = kmalloc(LBUFSIZE, GFP_KERNEL);
203    if (buf == NULL) {
204        DBG_FLT("binfmt_flat: no memory for read buffer\n");
205        retval = -ENOMEM;
206        goto out_free;
207    }
208
209    /* Read in first chunk of data and parse gzip header. */
210    fpos = offset;
211    ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
212
213    strm.next_in = buf;
214    strm.avail_in = ret;
215    strm.total_in = 0;
216
217    retval = -ENOEXEC;
218
219    /* Check minimum size -- gzip header */
220    if (ret < 10) {
221        DBG_FLT("binfmt_flat: file too small?\n");
222        goto out_free_buf;
223    }
224
225    /* Check gzip magic number */
226    if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
227        DBG_FLT("binfmt_flat: unknown compression magic?\n");
228        goto out_free_buf;
229    }
230
231    /* Check gzip method */
232    if (buf[2] != 8) {
233        DBG_FLT("binfmt_flat: unknown compression method?\n");
234        goto out_free_buf;
235    }
236    /* Check gzip flags */
237    if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
238        (buf[3] & RESERVED)) {
239        DBG_FLT("binfmt_flat: unknown flags?\n");
240        goto out_free_buf;
241    }
242
243    ret = 10;
244    if (buf[3] & EXTRA_FIELD) {
245        ret += 2 + buf[10] + (buf[11] << 8);
246        if (unlikely(LBUFSIZE <= ret)) {
247            DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
248            goto out_free_buf;
249        }
250    }
251    if (buf[3] & ORIG_NAME) {
252        while (ret < LBUFSIZE && buf[ret++] != 0)
253            ;
254        if (unlikely(LBUFSIZE == ret)) {
255            DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
256            goto out_free_buf;
257        }
258    }
259    if (buf[3] & COMMENT) {
260        while (ret < LBUFSIZE && buf[ret++] != 0)
261            ;
262        if (unlikely(LBUFSIZE == ret)) {
263            DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
264            goto out_free_buf;
265        }
266    }
267
268    strm.next_in += ret;
269    strm.avail_in -= ret;
270
271    strm.next_out = dst;
272    strm.avail_out = len;
273    strm.total_out = 0;
274
275    if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
276        DBG_FLT("binfmt_flat: zlib init failed?\n");
277        goto out_free_buf;
278    }
279
280    while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
281        ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
282        if (ret <= 0)
283            break;
284        len -= ret;
285
286        strm.next_in = buf;
287        strm.avail_in = ret;
288        strm.total_in = 0;
289    }
290
291    if (ret < 0) {
292        DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
293            ret, strm.msg);
294        goto out_zlib;
295    }
296
297    retval = 0;
298out_zlib:
299    zlib_inflateEnd(&strm);
300out_free_buf:
301    kfree(buf);
302out_free:
303    kfree(strm.workspace);
304    return retval;
305}
306
307#endif /* CONFIG_BINFMT_ZFLAT */
308
309/****************************************************************************/
310
311static unsigned long
312calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
313{
314    unsigned long addr;
315    int id;
316    unsigned long start_brk;
317    unsigned long start_data;
318    unsigned long text_len;
319    unsigned long start_code;
320
321#ifdef CONFIG_BINFMT_SHARED_FLAT
322    if (r == 0)
323        id = curid; /* Relocs of 0 are always self referring */
324    else {
325        id = (r >> 24) & 0xff; /* Find ID for this reloc */
326        r &= 0x00ffffff; /* Trim ID off here */
327    }
328    if (id >= MAX_SHARED_LIBS) {
329        printk("BINFMT_FLAT: reference 0x%x to shared library %d",
330                (unsigned) r, id);
331        goto failed;
332    }
333    if (curid != id) {
334        if (internalp) {
335            printk("BINFMT_FLAT: reloc address 0x%x not in same module "
336                    "(%d != %d)", (unsigned) r, curid, id);
337            goto failed;
338        } else if ( ! p->lib_list[id].loaded &&
339                IS_ERR_VALUE(load_flat_shared_library(id, p))) {
340            printk("BINFMT_FLAT: failed to load library %d", id);
341            goto failed;
342        }
343        /* Check versioning information (i.e. time stamps) */
344        if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
345                p->lib_list[curid].build_date < p->lib_list[id].build_date) {
346            printk("BINFMT_FLAT: library %d is younger than %d", id, curid);
347            goto failed;
348        }
349    }
350#else
351    id = 0;
352#endif
353
354    start_brk = p->lib_list[id].start_brk;
355    start_data = p->lib_list[id].start_data;
356    start_code = p->lib_list[id].start_code;
357    text_len = p->lib_list[id].text_len;
358
359    if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
360        printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)",
361               (int) r,(int)(start_brk-start_data+text_len),(int)text_len);
362        goto failed;
363    }
364
365    if (r < text_len) /* In text segment */
366        addr = r + start_code;
367    else /* In data segment */
368        addr = r - text_len + start_data;
369
370    /* Range checked already above so doing the range tests is redundant...*/
371    return(addr);
372
373failed:
374    printk(", killing %s!\n", current->comm);
375    send_sig(SIGSEGV, current, 0);
376
377    return RELOC_FAILED;
378}
379
380/****************************************************************************/
381
382void old_reloc(unsigned long rl)
383{
384#ifdef DEBUG
385    char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
386#endif
387    flat_v2_reloc_t r;
388    unsigned long *ptr;
389    
390    r.value = rl;
391#if defined(CONFIG_COLDFIRE)
392    ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
393#else
394    ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
395#endif
396
397#ifdef DEBUG
398    printk("Relocation of variable at DATASEG+%x "
399        "(address %p, currently %x) into segment %s\n",
400        r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
401#endif
402    
403    switch (r.reloc.type) {
404    case OLD_FLAT_RELOC_TYPE_TEXT:
405        *ptr += current->mm->start_code;
406        break;
407    case OLD_FLAT_RELOC_TYPE_DATA:
408        *ptr += current->mm->start_data;
409        break;
410    case OLD_FLAT_RELOC_TYPE_BSS:
411        *ptr += current->mm->end_data;
412        break;
413    default:
414        printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
415        break;
416    }
417
418#ifdef DEBUG
419    printk("Relocation became %x\n", (int)*ptr);
420#endif
421}
422
423/****************************************************************************/
424
425static int load_flat_file(struct linux_binprm * bprm,
426        struct lib_info *libinfo, int id, unsigned long *extra_stack)
427{
428    struct flat_hdr * hdr;
429    unsigned long textpos = 0, datapos = 0, result;
430    unsigned long realdatastart = 0;
431    unsigned long text_len, data_len, bss_len, stack_len, flags;
432    unsigned long len, memp = 0;
433    unsigned long memp_size, extra, rlim;
434    unsigned long *reloc = 0, *rp;
435    struct inode *inode;
436    int i, rev, relocs = 0;
437    loff_t fpos;
438    unsigned long start_code, end_code;
439    int ret;
440
441    hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
442    inode = bprm->file->f_path.dentry->d_inode;
443
444    text_len = ntohl(hdr->data_start);
445    data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
446    bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
447    stack_len = ntohl(hdr->stack_size);
448    if (extra_stack) {
449        stack_len += *extra_stack;
450        *extra_stack = stack_len;
451    }
452    relocs = ntohl(hdr->reloc_count);
453    flags = ntohl(hdr->flags);
454    rev = ntohl(hdr->rev);
455
456    if (strncmp(hdr->magic, "bFLT", 4)) {
457        /*
458         * Previously, here was a printk to tell people
459         * "BINFMT_FLAT: bad header magic".
460         * But for the kernel which also use ELF FD-PIC format, this
461         * error message is confusing.
462         * because a lot of people do not manage to produce good
463         */
464        ret = -ENOEXEC;
465        goto err;
466    }
467
468    if (flags & FLAT_FLAG_KTRACE)
469        printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
470
471    if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
472        printk("BINFMT_FLAT: bad flat file version 0x%x (supported "
473            "0x%lx and 0x%lx)\n",
474            rev, FLAT_VERSION, OLD_FLAT_VERSION);
475        ret = -ENOEXEC;
476        goto err;
477    }
478    
479    /* Don't allow old format executables to use shared libraries */
480    if (rev == OLD_FLAT_VERSION && id != 0) {
481        printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n",
482                (int) FLAT_VERSION);
483        ret = -ENOEXEC;
484        goto err;
485    }
486
487    /*
488     * fix up the flags for the older format, there were all kinds
489     * of endian hacks, this only works for the simple cases
490     */
491    if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
492        flags = FLAT_FLAG_RAM;
493
494#ifndef CONFIG_BINFMT_ZFLAT
495    if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
496        printk("Support for ZFLAT executables is not enabled.\n");
497        ret = -ENOEXEC;
498        goto err;
499    }
500#endif
501
502    /*
503     * Check initial limits. This avoids letting people circumvent
504     * size limits imposed on them by creating programs with large
505     * arrays in the data or bss.
506     */
507    rlim = rlimit(RLIMIT_DATA);
508    if (rlim >= RLIM_INFINITY)
509        rlim = ~0;
510    if (data_len + bss_len > rlim) {
511        ret = -ENOMEM;
512        goto err;
513    }
514
515    /* Flush all traces of the currently running executable */
516    if (id == 0) {
517        result = flush_old_exec(bprm);
518        if (result) {
519            ret = result;
520            goto err;
521        }
522
523        /* OK, This is the point of no return */
524        set_personality(PER_LINUX_32BIT);
525        setup_new_exec(bprm);
526    }
527
528    /*
529     * calculate the extra space we need to map in
530     */
531    extra = max_t(unsigned long, bss_len + stack_len,
532            relocs * sizeof(unsigned long));
533
534    /*
535     * there are a couple of cases here, the separate code/data
536     * case, and then the fully copied to RAM case which lumps
537     * it all together.
538     */
539    if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
540        /*
541         * this should give us a ROM ptr, but if it doesn't we don't
542         * really care
543         */
544        DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
545
546        down_write(&current->mm->mmap_sem);
547        textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
548                  MAP_PRIVATE|MAP_EXECUTABLE, 0);
549        up_write(&current->mm->mmap_sem);
550        if (!textpos || IS_ERR_VALUE(textpos)) {
551            if (!textpos)
552                textpos = (unsigned long) -ENOMEM;
553            printk("Unable to mmap process text, errno %d\n", (int)-textpos);
554            ret = textpos;
555            goto err;
556        }
557
558        len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
559        len = PAGE_ALIGN(len);
560        down_write(&current->mm->mmap_sem);
561        realdatastart = do_mmap(0, 0, len,
562            PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
563        up_write(&current->mm->mmap_sem);
564
565        if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
566            if (!realdatastart)
567                realdatastart = (unsigned long) -ENOMEM;
568            printk("Unable to allocate RAM for process data, errno %d\n",
569                    (int)-realdatastart);
570            do_munmap(current->mm, textpos, text_len);
571            ret = realdatastart;
572            goto err;
573        }
574        datapos = ALIGN(realdatastart +
575                MAX_SHARED_LIBS * sizeof(unsigned long),
576                FLAT_DATA_ALIGN);
577
578        DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
579                (int)(data_len + bss_len + stack_len), (int)datapos);
580
581        fpos = ntohl(hdr->data_start);
582#ifdef CONFIG_BINFMT_ZFLAT
583        if (flags & FLAT_FLAG_GZDATA) {
584            result = decompress_exec(bprm, fpos, (char *) datapos,
585                         data_len + (relocs * sizeof(unsigned long)), 0);
586        } else
587#endif
588        {
589            result = bprm->file->f_op->read(bprm->file, (char *) datapos,
590                    data_len + (relocs * sizeof(unsigned long)), &fpos);
591        }
592        if (IS_ERR_VALUE(result)) {
593            printk("Unable to read data+bss, errno %d\n", (int)-result);
594            do_munmap(current->mm, textpos, text_len);
595            do_munmap(current->mm, realdatastart, len);
596            ret = result;
597            goto err;
598        }
599
600        reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
601        memp = realdatastart;
602        memp_size = len;
603    } else {
604
605        len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
606        len = PAGE_ALIGN(len);
607        down_write(&current->mm->mmap_sem);
608        textpos = do_mmap(0, 0, len,
609            PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
610        up_write(&current->mm->mmap_sem);
611
612        if (!textpos || IS_ERR_VALUE(textpos)) {
613            if (!textpos)
614                textpos = (unsigned long) -ENOMEM;
615            printk("Unable to allocate RAM for process text/data, errno %d\n",
616                    (int)-textpos);
617            ret = textpos;
618            goto err;
619        }
620
621        realdatastart = textpos + ntohl(hdr->data_start);
622        datapos = ALIGN(realdatastart +
623                MAX_SHARED_LIBS * sizeof(unsigned long),
624                FLAT_DATA_ALIGN);
625
626        reloc = (unsigned long *)
627            (datapos + (ntohl(hdr->reloc_start) - text_len));
628        memp = textpos;
629        memp_size = len;
630#ifdef CONFIG_BINFMT_ZFLAT
631        /*
632         * load it all in and treat it like a RAM load from now on
633         */
634        if (flags & FLAT_FLAG_GZIP) {
635            result = decompress_exec(bprm, sizeof (struct flat_hdr),
636                     (((char *) textpos) + sizeof (struct flat_hdr)),
637                     (text_len + data_len + (relocs * sizeof(unsigned long))
638                          - sizeof (struct flat_hdr)),
639                     0);
640            memmove((void *) datapos, (void *) realdatastart,
641                    data_len + (relocs * sizeof(unsigned long)));
642        } else if (flags & FLAT_FLAG_GZDATA) {
643            fpos = 0;
644            result = bprm->file->f_op->read(bprm->file,
645                    (char *) textpos, text_len, &fpos);
646            if (!IS_ERR_VALUE(result))
647                result = decompress_exec(bprm, text_len, (char *) datapos,
648                         data_len + (relocs * sizeof(unsigned long)), 0);
649        }
650        else
651#endif
652        {
653            fpos = 0;
654            result = bprm->file->f_op->read(bprm->file,
655                    (char *) textpos, text_len, &fpos);
656            if (!IS_ERR_VALUE(result)) {
657                fpos = ntohl(hdr->data_start);
658                result = bprm->file->f_op->read(bprm->file, (char *) datapos,
659                    data_len + (relocs * sizeof(unsigned long)), &fpos);
660            }
661        }
662        if (IS_ERR_VALUE(result)) {
663            printk("Unable to read code+data+bss, errno %d\n",(int)-result);
664            do_munmap(current->mm, textpos, text_len + data_len + extra +
665                MAX_SHARED_LIBS * sizeof(unsigned long));
666            ret = result;
667            goto err;
668        }
669    }
670
671    if (flags & FLAT_FLAG_KTRACE)
672        printk("Mapping is %x, Entry point is %x, data_start is %x\n",
673            (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
674
675    /* The main program needs a little extra setup in the task structure */
676    start_code = textpos + sizeof (struct flat_hdr);
677    end_code = textpos + text_len;
678    if (id == 0) {
679        current->mm->start_code = start_code;
680        current->mm->end_code = end_code;
681        current->mm->start_data = datapos;
682        current->mm->end_data = datapos + data_len;
683        /*
684         * set up the brk stuff, uses any slack left in data/bss/stack
685         * allocation. We put the brk after the bss (between the bss
686         * and stack) like other platforms.
687         * Userspace code relies on the stack pointer starting out at
688         * an address right at the end of a page.
689         */
690        current->mm->start_brk = datapos + data_len + bss_len;
691        current->mm->brk = (current->mm->start_brk + 3) & ~3;
692        current->mm->context.end_brk = memp + memp_size - stack_len;
693    }
694
695    if (flags & FLAT_FLAG_KTRACE)
696        printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
697            id ? "Lib" : "Load", bprm->filename,
698            (int) start_code, (int) end_code,
699            (int) datapos,
700            (int) (datapos + data_len),
701            (int) (datapos + data_len),
702            (int) (((datapos + data_len + bss_len) + 3) & ~3));
703
704    text_len -= sizeof(struct flat_hdr); /* the real code len */
705
706    /* Store the current module values into the global library structure */
707    libinfo->lib_list[id].start_code = start_code;
708    libinfo->lib_list[id].start_data = datapos;
709    libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
710    libinfo->lib_list[id].text_len = text_len;
711    libinfo->lib_list[id].loaded = 1;
712    libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
713    libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
714    
715    /*
716     * We just load the allocations into some temporary memory to
717     * help simplify all this mumbo jumbo
718     *
719     * We've got two different sections of relocation entries.
720     * The first is the GOT which resides at the beginning of the data segment
721     * and is terminated with a -1. This one can be relocated in place.
722     * The second is the extra relocation entries tacked after the image's
723     * data segment. These require a little more processing as the entry is
724     * really an offset into the image which contains an offset into the
725     * image.
726     */
727    if (flags & FLAT_FLAG_GOTPIC) {
728        for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
729            unsigned long addr;
730            if (*rp) {
731                addr = calc_reloc(*rp, libinfo, id, 0);
732                if (addr == RELOC_FAILED) {
733                    ret = -ENOEXEC;
734                    goto err;
735                }
736                *rp = addr;
737            }
738        }
739    }
740
741    /*
742     * Now run through the relocation entries.
743     * We've got to be careful here as C++ produces relocatable zero
744     * entries in the constructor and destructor tables which are then
745     * tested for being not zero (which will always occur unless we're
746     * based from address zero). This causes an endless loop as __start
747     * is at zero. The solution used is to not relocate zero addresses.
748     * This has the negative side effect of not allowing a global data
749     * reference to be statically initialised to _stext (I've moved
750     * __start to address 4 so that is okay).
751     */
752    if (rev > OLD_FLAT_VERSION) {
753        unsigned long persistent = 0;
754        for (i=0; i < relocs; i++) {
755            unsigned long addr, relval;
756
757            /* Get the address of the pointer to be
758               relocated (of course, the address has to be
759               relocated first). */
760            relval = ntohl(reloc[i]);
761            if (flat_set_persistent (relval, &persistent))
762                continue;
763            addr = flat_get_relocate_addr(relval);
764            rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
765            if (rp == (unsigned long *)RELOC_FAILED) {
766                ret = -ENOEXEC;
767                goto err;
768            }
769
770            /* Get the pointer's value. */
771            addr = flat_get_addr_from_rp(rp, relval, flags,
772                            &persistent);
773            if (addr != 0) {
774                /*
775                 * Do the relocation. PIC relocs in the data section are
776                 * already in target order
777                 */
778                if ((flags & FLAT_FLAG_GOTPIC) == 0)
779                    addr = ntohl(addr);
780                addr = calc_reloc(addr, libinfo, id, 0);
781                if (addr == RELOC_FAILED) {
782                    ret = -ENOEXEC;
783                    goto err;
784                }
785
786                /* Write back the relocated pointer. */
787                flat_put_addr_at_rp(rp, addr, relval);
788            }
789        }
790    } else {
791        for (i=0; i < relocs; i++)
792            old_reloc(ntohl(reloc[i]));
793    }
794    
795    flush_icache_range(start_code, end_code);
796
797    /* zero the BSS, BRK and stack areas */
798    memset((void*)(datapos + data_len), 0, bss_len +
799            (memp + memp_size - stack_len - /* end brk */
800            libinfo->lib_list[id].start_brk) + /* start brk */
801            stack_len);
802
803    return 0;
804err:
805    return ret;
806}
807
808
809/****************************************************************************/
810#ifdef CONFIG_BINFMT_SHARED_FLAT
811
812/*
813 * Load a shared library into memory. The library gets its own data
814 * segment (including bss) but not argv/argc/environ.
815 */
816
817static int load_flat_shared_library(int id, struct lib_info *libs)
818{
819    struct linux_binprm bprm;
820    int res;
821    char buf[16];
822
823    memset(&bprm, 0, sizeof(bprm));
824
825    /* Create the file name */
826    sprintf(buf, "/lib/lib%d.so", id);
827
828    /* Open the file up */
829    bprm.filename = buf;
830    bprm.file = open_exec(bprm.filename);
831    res = PTR_ERR(bprm.file);
832    if (IS_ERR(bprm.file))
833        return res;
834
835    bprm.cred = prepare_exec_creds();
836    res = -ENOMEM;
837    if (!bprm.cred)
838        goto out;
839
840    /* We don't really care about recalculating credentials at this point
841     * as we're past the point of no return and are dealing with shared
842     * libraries.
843     */
844    bprm.cred_prepared = 1;
845
846    res = prepare_binprm(&bprm);
847
848    if (!IS_ERR_VALUE(res))
849        res = load_flat_file(&bprm, libs, id, NULL);
850
851    abort_creds(bprm.cred);
852
853out:
854    allow_write_access(bprm.file);
855    fput(bprm.file);
856
857    return(res);
858}
859
860#endif /* CONFIG_BINFMT_SHARED_FLAT */
861/****************************************************************************/
862
863/*
864 * These are the functions used to load flat style executables and shared
865 * libraries. There is no binary dependent code anywhere else.
866 */
867
868static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
869{
870    struct lib_info libinfo;
871    unsigned long p = bprm->p;
872    unsigned long stack_len;
873    unsigned long start_addr;
874    unsigned long *sp;
875    int res;
876    int i, j;
877
878    memset(&libinfo, 0, sizeof(libinfo));
879    /*
880     * We have to add the size of our arguments to our stack size
881     * otherwise it's too easy for users to create stack overflows
882     * by passing in a huge argument list. And yes, we have to be
883     * pedantic and include space for the argv/envp array as it may have
884     * a lot of entries.
885     */
886#define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
887    stack_len = TOP_OF_ARGS - bprm->p; /* the strings */
888    stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
889    stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
890    stack_len += FLAT_STACK_ALIGN - 1; /* reserve for upcoming alignment */
891    
892    res = load_flat_file(bprm, &libinfo, 0, &stack_len);
893    if (IS_ERR_VALUE(res))
894        return res;
895    
896    /* Update data segment pointers for all libraries */
897    for (i=0; i<MAX_SHARED_LIBS; i++)
898        if (libinfo.lib_list[i].loaded)
899            for (j=0; j<MAX_SHARED_LIBS; j++)
900                (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] =
901                    (libinfo.lib_list[j].loaded)?
902                        libinfo.lib_list[j].start_data:UNLOADED_LIB;
903
904    install_exec_creds(bprm);
905     current->flags &= ~PF_FORKNOEXEC;
906
907    set_binfmt(&flat_format);
908
909    p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
910    DBG_FLT("p=%x\n", (int)p);
911
912    /* copy the arg pages onto the stack, this could be more efficient :-) */
913    for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
914        * (char *) --p =
915            ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
916
917    sp = (unsigned long *) create_flat_tables(p, bprm);
918    
919    /* Fake some return addresses to ensure the call chain will
920     * initialise library in order for us. We are required to call
921     * lib 1 first, then 2, ... and finally the main program (id 0).
922     */
923    start_addr = libinfo.lib_list[0].entry;
924
925#ifdef CONFIG_BINFMT_SHARED_FLAT
926    for (i = MAX_SHARED_LIBS-1; i>0; i--) {
927        if (libinfo.lib_list[i].loaded) {
928            /* Push previos first to call address */
929            --sp; put_user(start_addr, sp);
930            start_addr = libinfo.lib_list[i].entry;
931        }
932    }
933#endif
934    
935    /* Stash our initial stack pointer into the mm structure */
936    current->mm->start_stack = (unsigned long )sp;
937
938#ifdef FLAT_PLAT_INIT
939    FLAT_PLAT_INIT(regs);
940#endif
941    DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
942        (int)regs, (int)start_addr, (int)current->mm->start_stack);
943    
944    start_thread(regs, start_addr, current->mm->start_stack);
945
946    return 0;
947}
948
949/****************************************************************************/
950
951static int __init init_flat_binfmt(void)
952{
953    return register_binfmt(&flat_format);
954}
955
956/****************************************************************************/
957
958core_initcall(init_flat_binfmt);
959
960/****************************************************************************/
961

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