#include <linux/module.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/a.out.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/malloc.h>
#include <linux/binfmts.h>
#include <linux/personality.h>
#include <asm/system.h>
#include <asm/segment.h>
#include <asm/pgtable.h>
static int load_aout_binary(struct linux_binprm *, struct pt_regs
* regs);
static int load_aout_library(int fd);
static int aout_core_dump(long signr, struct pt_regs * regs);
extern void dump_thread(struct pt_regs *, struct user *);
static struct linux_binfmt aout_format = {
#ifndef MODULE
NULL, NULL, load_aout_binary, load_aout_library, aout_core_dump
#else
NULL, &mod_use_count_, load_aout_binary, load_aout_library,
aout_core_dump
#endif
};
/* set_brk przydziela pamięc o wielkości end-start od adresu danego
zm. start */
static void set_brk(unsigned long start, unsigned long end)
{
start = PAGE_ALIGN(start);
end = PAGE_ALIGN(end);
if (end <= start)
return;
do_mmap(NULL, start, end - start,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE, 0);
}
/*
* These are the only things you should do on a core-file:
use only these
* macros to write out all the necessary info.
*/
#define DUMP_WRITE(addr,nr) \
while (file.f_op->write(inode,&file,(char *)(addr),(nr)) !=
(nr)) goto close_coredump
#define DUMP_SEEK(offset) \
if (file.f_op->lseek) { \
if (file.f_op->lseek(inode,&file,(offset),0) != (offset))
\
goto close_coredump; \
} else file.f_pos = (offset)
/*
* Routine writes a core dump image in the current directory.
* Currently only a stub-function.
*
* Note that setuid/setgid files won't make a core-dump if
the uid/gid
* changed due to the set[u|g]id. It's enforced by the "current->dumpable"
* field, which also makes sure the core-dumps won't be recursive
if the
* dumping of the process results in another error..
*/
static inline int
do_aout_core_dump(long signr, struct pt_regs * regs)
{
struct inode * inode = NULL;
struct file file;
unsigned short fs;
int has_dumped = 0;
char corefile[6+sizeof(current->comm)];
unsigned long dump_start, dump_size;
struct user dump;
#ifdef __alpha__
# define START_DATA(u) (u.start_data)
#else
# define START_DATA(u) (u.u_tsize
<< PAGE_SHIFT)
#endif
if (!current->dumpable || current->mm->count != 1)
return 0;
current->dumpable = 0;
/* See if we have enough room to write the upage. */
if (current->rlim[RLIMIT_CORE].rlim_cur < PAGE_SIZE)
return 0;
fs = get_fs();
set_fs(KERNEL_DS);
memcpy(corefile,"core.",5);
#if 0
memcpy(corefile+5,current->comm,sizeof(current->comm));
#else
corefile[4] = '\0';
#endif
if (open_namei(corefile,O_CREAT | 2 | O_TRUNC,0600,&inode,NULL))
{
inode = NULL;
goto end_coredump;
}
if (!S_ISREG(inode->i_mode))
goto end_coredump;
if (!inode->i_op || !inode->i_op->default_file_ops)
goto end_coredump;
if (get_write_access(inode))
goto end_coredump;
file.f_mode = 3;
file.f_flags = 0;
file.f_count = 1;
file.f_inode = inode;
file.f_pos = 0;
file.f_reada = 0;
file.f_op = inode->i_op->default_file_ops;
if (file.f_op->open)
if (file.f_op->open(inode,&file))
goto done_coredump;
if (!file.f_op->write)
goto close_coredump;
has_dumped = 1;
current->flags |= PF_DUMPCORE;
strncpy(dump.u_comm,
current->comm, sizeof(current->comm));
dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) -
((unsigned long)(&dump)));
dump.signal = signr;
dump_thread(regs, &dump);
/* If the size of the dump file exceeds the rlimit, then see what
would happen
if we wrote the stack, but not the data area.
*/
if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
current->rlim[RLIMIT_CORE].rlim_cur)
dump.u_dsize = 0;
/* Make sure we have enough room to write the stack and data areas.
*/
if ((dump.u_ssize+1) * PAGE_SIZE >
current->rlim[RLIMIT_CORE].rlim_cur)
dump.u_ssize = 0;
/* make sure we actually have a data and stack area to dump */
set_fs(USER_DS);
if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize
<< PAGE_SHIFT))
dump.u_dsize = 0;
if (verify_area(VERIFY_READ, (void *) dump.start_stack, dump.u_ssize
<< PAGE_SHIFT))
dump.u_ssize = 0;
set_fs(KERNEL_DS);
/* struct user */
DUMP_WRITE(&dump,sizeof(dump));
/* Now dump all of the user data. Include malloced stuff
as well */
DUMP_SEEK(PAGE_SIZE);
/* now we start writing out the user space info */
set_fs(USER_DS);
/* Dump the data area */
if (dump.u_dsize != 0) {
dump_start = START_DATA(dump);
dump_size = dump.u_dsize << PAGE_SHIFT;
DUMP_WRITE(dump_start,dump_size);
}
/* Now prepare to dump the stack area */
if (dump.u_ssize != 0) {
dump_start = dump.start_stack;
dump_size = dump.u_ssize << PAGE_SHIFT;
DUMP_WRITE(dump_start,dump_size);
}
/* Finally dump the task struct. Not be used by gdb, but
could be useful */
set_fs(KERNEL_DS);
DUMP_WRITE(current,sizeof(*current));
close_coredump:
if (file.f_op->release)
file.f_op->release(inode,&file);
done_coredump:
put_write_access(inode);
end_coredump:
set_fs(fs);
iput(inode);
return has_dumped;
}
static int
aout_core_dump(long signr, struct pt_regs * regs)
{
int retval;
MOD_INC_USE_COUNT;
retval = do_aout_core_dump(signr, regs);
MOD_DEC_USE_COUNT;
return retval;
}
/*
* create_aout_tables() parses the env- and arg-strings in
new user
* memory and creates the pointer tables from them, and puts
their
* addresses on the "stack", returning the new stack pointer
value.
*/
static unsigned long * create_aout_tables(char * p, struct linux_binprm
* bprm)
{
unsigned long *argv,*envp;
unsigned long * sp;
int argc = bprm->argc;
int envc = bprm->envc;
/* p - wskaźnik do początku "stosu"
powyżej p znajdują się ciągi środowiska i argumenty
oddzielone
znakami NULL */
sp = (unsigned long *) ((-(unsigned long)sizeof(char *))
& (unsigned long) p);
/* sp staje się p wyrównane do wielkości typu (char*) */
#ifdef __alpha__
/* whee.. test-programs are so much fun. */
put_user(0, --sp);
put_user(0, --sp);
if (bprm->loader) {
put_user(0, --sp);
put_user(0x3eb, --sp);
put_user(bprm->loader, --sp);
put_user(0x3ea, --sp);
}
put_user(bprm->exec, --sp);
put_user(0x3e9, --sp);
#endif
sp -= envc+1;
envp = sp;
sp -= argc+1;
argv = sp;
/* envp - początek tablicy napisów środowiska
argv - początek tablicy parametrów wywołania
sp - przesunął sie w lewo o liczbę parametrów
i rozmiar środ.*/
#if defined(__i386__) || defined(__mc68000__)
put_user(envp,--sp);
put_user(argv,--sp);
/* obliczone właśnie wskaźniki sa zapisywane do pamięci użytk.
*/
#endif
put_user(argc,--sp); /* teraz zapisujemy liczbę parametrów
*/
current->mm->arg_start = (unsigned long) p;
/* zapisujemy wskaźnik do środowiska i parametrów do task_struct
*/
while (argc-->0) { /* kopiowanie parametrów */
put_user(p,argv++);
while (get_user(p++)) /* nothing */ ; /* szukaj końca ciągu
*/
}
put_user(NULL,argv); /* znacznik końca (po co?) */
current->mm->arg_end = current->mm->env_start = (unsigned
long) p;
/* p wskazuje teraz
na początek ciągow środowiska, zapisujemy to do task_struct */
while (envc-->0) { /* kopiowanie zm. środowiska */
put_user(p,envp++);
while (get_user(p++)) /* nothing */ ;
}
put_user(NULL,envp);
current->mm->env_end = (unsigned long) p;
return sp;
}
/*
* These are the functions used to load a.out style executables
and shared
* libraries. There is no binary dependent code anywhere
else.
*/
static inline int
do_load_aout_binary(struct linux_binprm * bprm, struct pt_regs
* regs)
{
struct exec ex;
struct file * file;
int fd;
unsigned long error;
unsigned long p = bprm->p;
unsigned long fd_offset;
unsigned long rlim;
ex = *((struct exec *) bprm->buf); /* exec-header */
/* wychodzimy z błędem,
jesli rozmiar pliku nie zgadza się
lub
plik jest typu PURE_EXECUTABLE */
if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC
&&
N_MAGIC(ex) != QMAGIC) ||
N_TRSIZE(ex) || N_DRSIZE(ex) ||
bprm->inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex))
{
return -ENOEXEC;
}
current->personality = PER_LINUX;
fd_offset = N_TXTOFF(ex); /* początek czystego kodu w pliku
*/
#ifdef __i386__ /* ZMAGIC - proces ze stronicowaniem na żądanie
(demand-paged) */
if (N_MAGIC(ex) == ZMAGIC && fd_offset != BLOCK_SIZE)
{
printk(KERN_NOTICE "N_TXTOFF != BLOCK_SIZE. See a.out.h.\n");
return -ENOEXEC;
}
if (N_MAGIC(ex) == ZMAGIC && ex.a_text &&
(fd_offset < bprm->inode->i_sb->s_blocksize))
{
printk(KERN_NOTICE "N_TXTOFF < BLOCK_SIZE. Please convert
binary.\n");
return -ENOEXEC;
}
#endif
/* Check initial limits. This avoids letting people circumvent
* size limits imposed on them by creating programs with
large
* arrays in the data or bss.
*/
rlim = current->rlim[RLIMIT_DATA].rlim_cur;
if (rlim >= RLIM_INFINITY)
rlim = ~0;
if (ex.a_data + ex.a_bss > rlim)
return -ENOMEM;
if (flush_old_exec(bprm))
return -ENOMEM;
/* OK, This is the point of no return */
/* inicjujemy pola task_struct
wartościami z nagłówka pliku */
current->mm->end_code = ex.a_text +
(current->mm->start_code = N_TXTADDR(ex));
current->mm->end_data = ex.a_data +
(current->mm->start_data = N_DATADDR(ex));
current->mm->brk = ex.a_bss +
(current->mm->start_brk = N_BSSADDR(ex));
current->mm->rss = 0; /* liczba ramek procesu */
current->mm->mmap = NULL;
current->suid = current->euid = current->fsuid = bprm->e_uid;
current->sgid = current->egid = current->fsgid = bprm->e_gid;
current->flags &= ~PF_FORKNOEXEC;
if (N_MAGIC(ex) == OMAGIC) { /* zwykły plik wykonywalny */
#ifdef __alpha__
do_mmap(NULL, N_TXTADDR(ex) & PAGE_MASK,
ex.a_text+ex.a_data + PAGE_SIZE - 1,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FIXED|MAP_PRIVATE, 0);
read_exec(bprm->inode, fd_offset, (char *) N_TXTADDR(ex),
ex.a_text+ex.a_data, 0);
#else
do_mmap(NULL, 0, ex.a_text+ex.a_data,
/* przydział pamięci na kod i dane inicjowane wartościami z pliku
oraz ustawienie rejestru segmentowego danych na przydzielony
obszar
Od tej pory znajduje się on pod (offset: 0) (to wlasnie
oznacza do_mmap(NULL,0...)) */
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FIXED|MAP_PRIVATE, 0);
read_exec(bprm->inode, 32, (char *) 0, ex.a_text+ex.a_data,
0);
#endif
} else {
/* proces stronicowany - wielkość kodu i danych musi byc wielokrotnościa
4096 */
if (ex.a_text & 0xfff || ex.a_data & 0xfff)
printk(KERN_NOTICE "executable not page aligned\n");
fd = open_inode(bprm->inode, O_RDONLY);
if (fd < 0)
return fd;
file = current->files->fd[fd];
if (!file->f_op || !file->f_op->mmap) {
/* jesli plik nie moze byc stronicowany, tj. odwzorowany ("map")
w pamieci,
to po staremu przydzielamy segment pam. i kopiujemy
zawartość z dysku */
sys_close(fd);
do_mmap(NULL, 0, ex.a_text+ex.a_data,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FIXED|MAP_PRIVATE, 0);
read_exec(bprm->inode, fd_offset,
(char *) N_TXTADDR(ex), ex.a_text+ex.a_data,
0);
goto beyond_if;
}
/* w przeciwnym wypadku wykonujemy odwzorowanie pliku do pamięci
proces będzie miał wszystkie strony zrzucone na dysk
Wczytywanie kodu i danych z dysku będzie odbywać się
"na życzenie" - kolejne odwołania będą powodować wyjątek braku strony i
doczytanie jej przez mechanizm pamięci wirtualnej */
error = do_mmap(file, N_TXTADDR(ex), ex.a_text,
PROT_READ | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
fd_offset);
if (error != N_TXTADDR(ex)) {
sys_close(fd);
send_sig(SIGKILL, current, 0);
return error;
}
error = do_mmap(file, N_DATADDR(ex), ex.a_data,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
fd_offset + ex.a_text);
sys_close(fd);
/* jesli coś poszło nie tak, to popełniamy samobójstwo */
if (error != N_DATADDR(ex)) {
send_sig(SIGKILL, current, 0);
return error;
}
}
beyond_if: /* zmniejszamy licznik instancji o domenie wykonywania
i formacie usuniętego procesu, a zwiększamy liczniki dotyczące nowej domeny
i formatu */
if (current->exec_domain && current->exec_domain->use_count)
(*current->exec_domain->use_count)--;
if (current->binfmt && current->binfmt->use_count)
(*current->binfmt->use_count)--;
current->exec_domain = lookup_exec_domain(current->personality);
current->binfmt = &aout_format;
if (current->exec_domain && current->exec_domain->use_count)
(*current->exec_domain->use_count)++;
if (current->binfmt && current->binfmt->use_count)
(*current->binfmt->use_count)++;
/* przydział pamięci na zmienne nieinicjowane */
set_brk(current->mm->start_brk, current->mm->brk);
p = setup_arg_pages(p, bprm);
/* kopiuje fragment pamięci zawierający parametry i środowisko
z pam. jądra do przestrzeni adresowej procesu. Teraz nastąpi konwersja
z ciągu przedzielanego znakami NULL na tablice wskaźników typu (char*)
*/
p = (unsigned long) create_aout_tables((char *)p, bprm);
current->mm->start_stack = p;
#ifdef __alpha__
regs->gp = ex.a_gpvalue;
#endif
/* wreszcie, uruchamiamy proces */
start_thread(regs, ex.a_entry, p);
/* jesli proces jest śledzony, to zawieszamy go (praca krokowa)
*/
if (current->flags & PF_PTRACED)
send_sig(SIGTRAP, current, 0);
return 0;
}
static int
load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
int retval;
MOD_INC_USE_COUNT;
retval = do_load_aout_binary(bprm, regs);
MOD_DEC_USE_COUNT;
return retval;
}
static inline int
do_load_aout_library(int fd)
{
struct file * file;
struct exec ex;
struct inode * inode;
unsigned int len;
unsigned int bss;
unsigned int start_addr;
unsigned long error;
file = current->files->fd[fd];
inode = file->f_inode;
if (!file || !file->f_op)
return -EACCES;
/* Seek into the file */
if (file->f_op->lseek) {
if ((error = file->f_op->lseek(inode, file, 0, 0)) != 0)
return -ENOEXEC;
} else
file->f_pos = 0;
set_fs(KERNEL_DS);
/* wczytywanie nagłówka biblioteki (ex) do pamięci jądra
read wczytuje do segmentu wskazywanego
przez rejestr FS procesora,
stąd trzeba go najpierw ustawić na segment danych
jądra */
error = file->f_op->read(inode, file, (char *) &ex, sizeof(ex));
set_fs(USER_DS);
if (error != sizeof(ex))
return -ENOEXEC;
/* We come in here for the regular a.out style of shared libraries
*/
/* sprawdzenie formatu
pliku, oraz czy jego wielkosć zgadza się
z zadeklarowaną w nagłówku */
/* billioteka MUSI byc
stronicowana (ZMAGIC lub QMAGIC) */
if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC)
|| N_TRSIZE(ex) ||
N_DRSIZE(ex) || ((ex.a_entry & 0xfff)
&& N_MAGIC(ex) == ZMAGIC) ||
inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex))
{
return -ENOEXEC;
}
/* jesli nagłówek nie
jest w kodzie, to kod musi zaczynać się w
kolejnym bloku */
if (N_MAGIC(ex) == ZMAGIC && N_TXTOFF(ex) &&
(N_TXTOFF(ex) < inode->i_sb->s_blocksize))
{
printk("N_TXTOFF <
BLOCK_SIZE. Please convert library\n");
return -ENOEXEC;
}
if (N_FLAGS(ex)) return -ENOEXEC;
/* For QMAGIC, the starting address is 0x20 into the
page. We mask
this off to get the starting address for the
page */
/* nagłówek w tym przypadku ma 32 bajty, bezpośrednio dalej
- kod. */
start_addr = ex.a_entry & 0xfffff000;
/* wyrównanie do początku
strony */
/* w dół - PAGE_ALIGN(..)
wykonuje wyrównanie w górę */
/* Now use mmap to map the library into memory. */
error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
N_TXTOFF(ex));
if (error != start_addr)
return error;
len = PAGE_ALIGN(ex.a_text + ex.a_data);
/* rozmiar kodu i danych
inicjowanych wyrównany do wielkości strony */
bss = ex.a_text + ex.a_data + ex.a_bss;
/* jesli za mało na
dane nie inicjowane, to przydzielamy jeszcze */
if (bss > len) {
error = do_mmap(NULL, start_addr + len, bss-len,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED, 0);
if (error != start_addr + len)
return error;
}
return 0;}
static int
load_aout_library(int fd)
{
int retval;
MOD_INC_USE_COUNT;
retval = do_load_aout_library(fd);
MOD_DEC_USE_COUNT;
return retval;
}
/* Dodaje format a.out do listy formatow "formats" */
int init_aout_binfmt(void) {
return register_binfmt(&aout_format);
}
#ifdef MODULE
int init_module(void) {
return init_aout_binfmt();
}
/* Usuwa format a.out z listy formatow */
void cleanup_module( void) {
unregister_binfmt(&aout_format);
}
#endif