binutils-gdb/gdb/exec.c

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1991-03-28 17:26:26 +01:00
/* Work with executable files, for GDB.
Copyright (C) 1988, 1989 Free Software Foundation, Inc.
This file is part of GDB.
GDB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.
GDB is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GDB; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <stdio.h>
#include "defs.h"
#include "param.h"
#include "frame.h"
#include "inferior.h"
#include "target.h"
#ifdef USG
#include <sys/types.h>
#endif
#include <sys/param.h>
#include <fcntl.h>
#include "gdbcore.h"
#ifdef STILL_NEEDED_FOR_DECSTATION
#include <sys/dir.h> /* For DECstations */
#include <sys/user.h> /* After a.out.h */
#include <sys/file.h>
#endif
#include <sys/stat.h>
extern char *getenv();
extern void child_create_inferior (), child_attach ();
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extern void add_syms_addr_command ();
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extern void symbol_file_command ();
/* The Binary File Descriptor handle for the executable file. */
bfd *exec_bfd = NULL;
/* The base and bounds of the table of the exec file's sections. */
struct section_table *exec_sections, *exec_sections_end;
/* Forward decl */
extern struct target_ops exec_ops;
void
exec_close (quitting)
int quitting;
{
if (exec_bfd) {
bfd_close (exec_bfd);
exec_bfd = NULL;
}
}
void
exec_file_command (filename, from_tty)
char *filename;
int from_tty;
{
/* Remove any previous exec file. */
unpush_target (&exec_ops);
/* Now open and digest the file the user requested, if any. */
if (filename)
{
char *scratch_pathname;
int scratch_chan;
filename = tilde_expand (filename);
make_cleanup (free, filename);
/* FIXME, if writeable is set, open for read/write. */
scratch_chan = openp (getenv ("PATH"), 1, filename, O_RDONLY, 0,
&scratch_pathname);
if (scratch_chan < 0)
perror_with_name (filename);
exec_bfd = bfd_fdopenr (scratch_pathname, NULL, scratch_chan);
if (!exec_bfd)
error ("Could not open `%s' as an executable file: %s",
scratch_pathname, bfd_errmsg (bfd_error));
if (!bfd_check_format (exec_bfd, bfd_object))
error ("\"%s\": not in executable format: %s.",
scratch_pathname, bfd_errmsg (bfd_error));
#if FIXME
/* This code needs to be incorporated into BFD */
#ifdef COFF_ENCAPSULATE
/* If we have a coff header, it can give us better values for
text_start and exec_data_start. This is particularly useful
for remote debugging of embedded systems. */
if (N_FLAGS(exec_aouthdr) & N_FLAGS_COFF_ENCAPSULATE)
{
struct coffheader ch;
int val;
val = lseek (execchan, -(sizeof (AOUTHDR) + sizeof (ch)), 1);
if (val == -1)
perror_with_name (filename);
val = myread (execchan, &ch, sizeof (ch));
if (val < 0)
perror_with_name (filename);
text_start = ch.text_start;
exec_data_start = ch.data_start;
} else
#endif
{
text_start =
IS_OBJECT_FILE (exec_aouthdr) ? 0 : N_TXTADDR (exec_aouthdr);
exec_data_start = IS_OBJECT_FILE (exec_aouthdr)
? exec_aouthdr.a_text : N_DATADDR (exec_aouthdr);
}
#endif FIXME
if (build_section_table (exec_bfd, &exec_sections, &exec_sections_end))
error ("Can't find the file sections in `%s': %s",
exec_bfd->filename, bfd_errmsg (bfd_error));
validate_files ();
push_target (&exec_ops);
/* Tell display code (if any) about the changed file name. */
if (exec_file_display_hook)
(*exec_file_display_hook) (filename);
}
else if (from_tty)
printf ("No exec file now.\n");
}
/* Set both the exec file and the symbol file, in one command.
What a novelty. Why did GDB go through four major releases before this
command was added? */
void
file_command (arg, from_tty)
char *arg;
int from_tty;
{
/* FIXME, if we lose on reading the symbol file, we should revert
the exec file, but that's rough. */
exec_file_command (arg, from_tty);
symbol_file_command (arg, from_tty);
}
/* Locate all mappable sections of a BFD file. */
void
add_to_section_table (abfd, asect, table_pp)
bfd *abfd;
sec_ptr asect;
struct section_table **table_pp;
{
flagword aflag;
aflag = bfd_get_section_flags (abfd, asect);
/* FIXME, we need to handle BSS segment here...it alloc's but doesn't load */
if (!(aflag & SEC_LOAD))
return;
(*table_pp)->sec_ptr = asect;
(*table_pp)->addr = bfd_section_vma (abfd, asect);
(*table_pp)->endaddr = (*table_pp)->addr + bfd_section_size (abfd, asect);
(*table_pp)++;
}
int
build_section_table (some_bfd, start, end)
bfd *some_bfd;
struct section_table **start, **end;
{
unsigned count;
count = bfd_count_sections (some_bfd);
if (count == 0)
abort(); /* return 1? */
*start = (struct section_table *) xmalloc (count * sizeof (**start));
*end = *start;
bfd_map_over_sections (some_bfd, add_to_section_table, end);
if (*end > *start + count)
abort();
/* We could realloc the table, but it probably loses for most files. */
return 0;
}
/* Read or write the exec file.
Args are address within exec file, address within gdb address-space,
length, and a flag indicating whether to read or write.
Result is a length:
0: We cannot handle this address and length.
> 0: We have handled N bytes starting at this address.
(If N == length, we did it all.) We might be able
to handle more bytes beyond this length, but no
promises.
< 0: We cannot handle this address, but if somebody
else handles (-N) bytes, we can start from there.
The same routine is used to handle both core and exec files;
we just tail-call it with more arguments to select between them. */
int
xfer_memory (memaddr, myaddr, len, write, abfd, sections, sections_end)
CORE_ADDR memaddr;
char *myaddr;
int len;
int write;
bfd *abfd;
struct section_table *sections, *sections_end;
{
boolean res;
struct section_table *p;
CORE_ADDR nextsectaddr, memend;
boolean (*xfer_fn) ();
if (len <= 0)
abort();
memend = memaddr + len;
xfer_fn = write? bfd_set_section_contents: bfd_get_section_contents;
nextsectaddr = memend;
for (p = sections; p < sections_end; p++)
{
if (p->addr <= memaddr)
if (p->endaddr >= memend)
{
/* Entire transfer is within this section. */
res = xfer_fn (abfd, p->sec_ptr, myaddr, memaddr - p->addr, len);
return (res != false)? len: 0;
}
else if (p->endaddr <= memaddr)
{
/* This section ends before the transfer starts. */
continue;
}
else
{
/* This section overlaps the transfer. Just do half. */
len = p->endaddr - memaddr;
res = xfer_fn (abfd, p->sec_ptr, myaddr, memaddr - p->addr, len);
return (res != false)? len: 0;
}
else if (p->addr < nextsectaddr)
nextsectaddr = p->addr;
}
if (nextsectaddr >= memend)
return 0; /* We can't help */
else
return - (nextsectaddr - memaddr); /* Next boundary where we can help */
}
/* The function called by target_xfer_memory via our target_ops */
int
exec_xfer_memory (memaddr, myaddr, len, write)
CORE_ADDR memaddr;
char *myaddr;
int len;
int write;
{
return xfer_memory (memaddr, myaddr, len, write,
exec_bfd, exec_sections, exec_sections_end);
}
#ifdef FIXME
#ifdef REG_STACK_SEGMENT
/* MOVE TO BFD... */
/* Pyramids and AM29000s have an extra segment in the virtual address space
for the (control) stack of register-window frames. The AM29000 folk
call it the "register stack" rather than the "memory stack". */
else if (memaddr >= reg_stack_start && memaddr < reg_stack_end)
{
i = min (len, reg_stack_end - memaddr);
fileptr = memaddr - reg_stack_start + reg_stack_offset;
wanna_xfer = coredata;
}
#endif /* REG_STACK_SEGMENT */
#endif FIXME
static void
exec_files_info ()
{
struct section_table *p;
printf ("\tExecutable file `%s'.\n", bfd_get_filename(exec_bfd));
for (p = exec_sections; p < exec_sections_end; p++)
printf("\texecutable from 0x%08x to 0x%08x is %s\n",
p->addr, p->endaddr,
bfd_section_name (exec_bfd, p->sec_ptr));
}
struct target_ops exec_ops = {
"exec", "Local exec file",
exec_file_command, exec_close, /* open, close */
child_attach, 0, 0, 0, /* attach, detach, resume, wait, */
0, 0, /* fetch_registers, store_registers, */
0, 0, 0, /* prepare_to_store, conv_to, conv_from, */
exec_xfer_memory, exec_files_info,
0, 0, /* insert_breakpoint, remove_breakpoint, */
0, 0, 0, 0, 0, /* terminal stuff */
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0, 0, /* kill, load */
add_syms_addr_command,
0, 0, /* call fn, lookup sym */
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child_create_inferior,
0, /* mourn_inferior */
file_stratum, 0, /* next */
0, 1, 0, 0, 0, /* all mem, mem, stack, regs, exec */
OPS_MAGIC, /* Always the last thing */
};
void
_initialize_exec()
{
add_com ("file", class_files, file_command,
"Use FILE as program to be debugged.\n\
It is read for its symbols, for getting the contents of pure memory,\n\
and it is the program executed when you use the `run' command.\n\
If FILE cannot be found as specified, your execution directory path\n\
($PATH) is searched for a command of that name.\n\
No arg means to have no executable file and no symbols.");
add_com ("exec-file", class_files, exec_file_command,
"Use FILE as program for getting contents of pure memory.\n\
If FILE cannot be found as specified, your execution directory path\n\
is searched for a command of that name.\n\
No arg means have no executable file.");
add_target (&exec_ops);
}