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binutils-gdb/gdb/solib.c

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/* Handle SunOS and SVR4 shared libraries for GDB, the GNU Debugger.
Copyright 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
This file is part of GDB.
This program 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 2 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "defs.h"
#include <sys/types.h>
#include <signal.h>
#include <string.h>
#include <link.h>
#include <sys/param.h>
#include <fcntl.h>
#ifndef SVR4_SHARED_LIBS
/* SunOS shared libs need the nlist structure. */
#include <a.out.h>
#else
#include "libelf.h"
#ifndef DT_MIPS_RLD_MAP
#include "elf/mips.h"
#endif
#endif
#include "symtab.h"
#include "bfd.h"
#include "symfile.h"
#include "objfiles.h"
#include "gdbcore.h"
#include "command.h"
#include "target.h"
#include "frame.h"
#include "regex.h"
#include "inferior.h"
#include "language.h"
#define MAX_PATH_SIZE 256 /* FIXME: Should be dynamic */
/* On SVR4 systems, for the initial implementation, use some runtime startup
symbol as the "startup mapping complete" breakpoint address. The models
for SunOS and SVR4 dynamic linking debugger support are different in that
SunOS hits one breakpoint when all mapping is complete while using the SVR4
debugger support takes two breakpoint hits for each file mapped, and
there is no way to know when the "last" one is hit. Both these
mechanisms should be tied to a "breakpoint service routine" that
gets automatically executed whenever one of the breakpoints indicating
a change in mapping is hit. This is a future enhancement. (FIXME) */
#define BKPT_AT_SYMBOL 1
#if defined (BKPT_AT_SYMBOL) && defined (SVR4_SHARED_LIBS)
static char *bkpt_names[] = {
#ifdef SOLIB_BKPT_NAME
SOLIB_BKPT_NAME, /* Prefer configured name if it exists. */
#endif
"_start",
"main",
NULL
};
#endif
/* Symbols which are used to locate the base of the link map structures. */
#ifndef SVR4_SHARED_LIBS
static char *debug_base_symbols[] = {
"_DYNAMIC",
NULL
};
#endif
/* local data declarations */
#ifndef SVR4_SHARED_LIBS
#define LM_ADDR(so) ((so) -> lm.lm_addr)
#define LM_NEXT(so) ((so) -> lm.lm_next)
#define LM_NAME(so) ((so) -> lm.lm_name)
/* Test for first link map entry; first entry is a shared library. */
#define IGNORE_FIRST_LINK_MAP_ENTRY(x) (0)
static struct link_dynamic dynamic_copy;
static struct link_dynamic_2 ld_2_copy;
static struct ld_debug debug_copy;
static CORE_ADDR debug_addr;
static CORE_ADDR flag_addr;
#else /* SVR4_SHARED_LIBS */
#define LM_ADDR(so) ((so) -> lm.l_addr)
#define LM_NEXT(so) ((so) -> lm.l_next)
#define LM_NAME(so) ((so) -> lm.l_name)
/* Test for first link map entry; first entry is the exec-file. */
#define IGNORE_FIRST_LINK_MAP_ENTRY(x) ((x).l_prev == NULL)
static struct r_debug debug_copy;
char shadow_contents[BREAKPOINT_MAX]; /* Stash old bkpt addr contents */
#endif /* !SVR4_SHARED_LIBS */
struct so_list {
struct so_list *next; /* next structure in linked list */
struct link_map lm; /* copy of link map from inferior */
struct link_map *lmaddr; /* addr in inferior lm was read from */
CORE_ADDR lmend; /* upper addr bound of mapped object */
char so_name[MAX_PATH_SIZE]; /* shared object lib name (FIXME) */
char symbols_loaded; /* flag: symbols read in yet? */
char from_tty; /* flag: print msgs? */
struct objfile *objfile; /* objfile for loaded lib */
struct section_table *sections;
struct section_table *sections_end;
struct section_table *textsection;
bfd *abfd;
};
static struct so_list *so_list_head; /* List of known shared objects */
static CORE_ADDR debug_base; /* Base of dynamic linker structures */
static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */
extern int
fdmatch PARAMS ((int, int)); /* In libiberty */
/* Local function prototypes */
static void
special_symbol_handling PARAMS ((struct so_list *));
static void
sharedlibrary_command PARAMS ((char *, int));
static int
enable_break PARAMS ((void));
static int
disable_break PARAMS ((void));
static void
info_sharedlibrary_command PARAMS ((char *, int));
static int
symbol_add_stub PARAMS ((char *));
static struct so_list *
find_solib PARAMS ((struct so_list *));
static struct link_map *
first_link_map_member PARAMS ((void));
static CORE_ADDR
locate_base PARAMS ((void));
static void
solib_map_sections PARAMS ((struct so_list *));
#ifdef SVR4_SHARED_LIBS
static CORE_ADDR
elf_locate_base PARAMS ((void));
#else
static void
solib_add_common_symbols PARAMS ((struct rtc_symb *, struct objfile *));
#endif
/*
LOCAL FUNCTION
solib_map_sections -- open bfd and build sections for shared lib
SYNOPSIS
static void solib_map_sections (struct so_list *so)
DESCRIPTION
Given a pointer to one of the shared objects in our list
of mapped objects, use the recorded name to open a bfd
descriptor for the object, build a section table, and then
relocate all the section addresses by the base address at
which the shared object was mapped.
FIXMES
In most (all?) cases the shared object file name recorded in the
dynamic linkage tables will be a fully qualified pathname. For
cases where it isn't, do we really mimic the systems search
mechanism correctly in the below code (particularly the tilde
expansion stuff?).
*/
static void
solib_map_sections (so)
struct so_list *so;
{
char *filename;
char *scratch_pathname;
int scratch_chan;
struct section_table *p;
struct cleanup *old_chain;
bfd *abfd;
filename = tilde_expand (so -> so_name);
old_chain = make_cleanup (free, filename);
scratch_chan = openp (getenv ("PATH"), 1, filename, O_RDONLY, 0,
&scratch_pathname);
if (scratch_chan < 0)
{
scratch_chan = openp (getenv ("LD_LIBRARY_PATH"), 1, filename,
O_RDONLY, 0, &scratch_pathname);
}
if (scratch_chan < 0)
{
perror_with_name (filename);
}
/* Leave scratch_pathname allocated. abfd->name will point to it. */
abfd = bfd_fdopenr (scratch_pathname, gnutarget, scratch_chan);
if (!abfd)
{
close (scratch_chan);
error ("Could not open `%s' as an executable file: %s",
scratch_pathname, bfd_errmsg (bfd_get_error ()));
}
/* Leave bfd open, core_xfer_memory and "info files" need it. */
so -> abfd = abfd;
abfd -> cacheable = true;
if (!bfd_check_format (abfd, bfd_object))
{
error ("\"%s\": not in executable format: %s.",
scratch_pathname, bfd_errmsg (bfd_get_error ()));
}
if (build_section_table (abfd, &so -> sections, &so -> sections_end))
{
error ("Can't find the file sections in `%s': %s",
bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ()));
}
for (p = so -> sections; p < so -> sections_end; p++)
{
/* Relocate the section binding addresses as recorded in the shared
object's file by the base address to which the object was actually
mapped. */
p -> addr += (CORE_ADDR) LM_ADDR (so);
p -> endaddr += (CORE_ADDR) LM_ADDR (so);
so -> lmend = (CORE_ADDR) max (p -> endaddr, so -> lmend);
if (STREQ (p -> the_bfd_section -> name, ".text"))
{
so -> textsection = p;
}
}
/* Free the file names, close the file now. */
do_cleanups (old_chain);
}
/* Read all dynamically loaded common symbol definitions from the inferior
and add them to the minimal symbol table for the shared library objfile. */
#ifndef SVR4_SHARED_LIBS
/* In GDB 4.9 this routine was a real performance hog. According to
some gprof data which mtranle@paris.IntelliCorp.COM (Minh Tran-Le)
sent, almost all the time spend in solib_add (up to 20 minutes with
35 shared libraries) was spent here, with 5/6 in
lookup_minimal_symbol and 1/6 in read_memory.
To fix this, we moved the call to special_symbol_handling out of the
loop in solib_add, so this only gets called once, rather than once
for every shared library, and also removed the call to lookup_minimal_symbol
in this routine. */
static void
solib_add_common_symbols (rtc_symp, objfile)
struct rtc_symb *rtc_symp;
struct objfile *objfile;
{
struct rtc_symb inferior_rtc_symb;
struct nlist inferior_rtc_nlist;
int len;
char *name;
char *origname;
init_minimal_symbol_collection ();
make_cleanup (discard_minimal_symbols, 0);
while (rtc_symp)
{
read_memory ((CORE_ADDR) rtc_symp,
(char *) &inferior_rtc_symb,
sizeof (inferior_rtc_symb));
read_memory ((CORE_ADDR) inferior_rtc_symb.rtc_sp,
(char *) &inferior_rtc_nlist,
sizeof(inferior_rtc_nlist));
if (inferior_rtc_nlist.n_type == N_COMM)
{
/* FIXME: The length of the symbol name is not available, but in the
current implementation the common symbol is allocated immediately
behind the name of the symbol. */
len = inferior_rtc_nlist.n_value - inferior_rtc_nlist.n_un.n_strx;
origname = name = xmalloc (len);
read_memory ((CORE_ADDR) inferior_rtc_nlist.n_un.n_name, name, len);
/* Don't enter the symbol twice if the target is re-run. */
if (name[0] == bfd_get_symbol_leading_char (objfile->obfd))
{
name++;
}
#if 0
/* I think this is unnecessary, GDB can probably deal with
duplicate minimal symbols, more or less. And the duplication
which used to happen because this was called for each shared
library is gone now that we are just called once. */
/* FIXME: Do we really want to exclude symbols which happen
to match symbols for other locations in the inferior's
address space, even when they are in different linkage units? */
if (lookup_minimal_symbol (name, (struct objfile *) NULL) == NULL)
#endif
{
name = obsavestring (name, strlen (name),
&objfile -> symbol_obstack);
prim_record_minimal_symbol (name, inferior_rtc_nlist.n_value,
mst_bss, objfile);
}
free (origname);
}
rtc_symp = inferior_rtc_symb.rtc_next;
}
/* Install any minimal symbols that have been collected as the current
minimal symbols for this objfile. */
install_minimal_symbols (objfile);
}
#endif /* SVR4_SHARED_LIBS */
#ifdef SVR4_SHARED_LIBS
/*
LOCAL FUNCTION
elf_locate_base -- locate the base address of dynamic linker structs
for SVR4 elf targets.
SYNOPSIS
CORE_ADDR elf_locate_base (void)
DESCRIPTION
For SVR4 elf targets the address of the dynamic linker's runtime
structure is contained within the dynamic info section in the
executable file. The dynamic section is also mapped into the
inferior address space. Because the runtime loader fills in the
real address before starting the inferior, we have to read in the
dynamic info section from the inferior address space.
If there are any errors while trying to find the address, we
silently return 0, otherwise the found address is returned.
*/
static CORE_ADDR
elf_locate_base ()
{
struct elf_internal_shdr *dyninfo_sect;
int dyninfo_sect_size;
CORE_ADDR dyninfo_addr;
char *buf;
char *bufend;
/* Find the start address of the .dynamic section. */
if (exec_bfd == NULL || bfd_get_flavour (exec_bfd) != bfd_target_elf_flavour)
return 0;
dyninfo_sect = bfd_elf_find_section (exec_bfd, ".dynamic");
if (dyninfo_sect == NULL)
return 0;
dyninfo_addr = dyninfo_sect->sh_addr;
/* Read in .dynamic section, silently ignore errors. */
dyninfo_sect_size = dyninfo_sect->sh_size;
buf = alloca (dyninfo_sect_size);
if (target_read_memory (dyninfo_addr, buf, dyninfo_sect_size))
return 0;
/* Find the DT_DEBUG entry in the the .dynamic section.
For mips elf we look for DT_MIPS_RLD_MAP, mips elf apparently has
no DT_DEBUG entries. */
/* FIXME: In lack of a 64 bit ELF ABI the following code assumes
a 32 bit ELF ABI target. */
for (bufend = buf + dyninfo_sect_size;
buf < bufend;
buf += sizeof (Elf32_External_Dyn))
{
Elf32_External_Dyn *x_dynp = (Elf32_External_Dyn *)buf;
long dyn_tag;
CORE_ADDR dyn_ptr;
dyn_tag = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_tag);
if (dyn_tag == DT_NULL)
break;
else if (dyn_tag == DT_DEBUG)
{
dyn_ptr = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_un.d_ptr);
return dyn_ptr;
}
else if (dyn_tag == DT_MIPS_RLD_MAP)
{
char pbuf[TARGET_PTR_BIT / HOST_CHAR_BIT];
/* DT_MIPS_RLD_MAP contains a pointer to the address
of the dynamic link structure. */
dyn_ptr = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_un.d_ptr);
if (target_read_memory (dyn_ptr, pbuf, sizeof (pbuf)))
return 0;
return extract_unsigned_integer (pbuf, sizeof (pbuf));
}
}
/* DT_DEBUG entry not found. */
return 0;
}
#endif /* SVR4_SHARED_LIBS */
/*
LOCAL FUNCTION
locate_base -- locate the base address of dynamic linker structs
SYNOPSIS
CORE_ADDR locate_base (void)
DESCRIPTION
For both the SunOS and SVR4 shared library implementations, if the
inferior executable has been linked dynamically, there is a single
address somewhere in the inferior's data space which is the key to
locating all of the dynamic linker's runtime structures. This
address is the value of the debug base symbol. The job of this
function is to find and return that address, or to return 0 if there
is no such address (the executable is statically linked for example).
For SunOS, the job is almost trivial, since the dynamic linker and
all of it's structures are statically linked to the executable at
link time. Thus the symbol for the address we are looking for has
already been added to the minimal symbol table for the executable's
objfile at the time the symbol file's symbols were read, and all we
have to do is look it up there. Note that we explicitly do NOT want
to find the copies in the shared library.
The SVR4 version is a bit more complicated because the address
is contained somewhere in the dynamic info section. We have to go
to a lot more work to discover the address of the debug base symbol.
Because of this complexity, we cache the value we find and return that
value on subsequent invocations. Note there is no copy in the
executable symbol tables.
*/
static CORE_ADDR
locate_base ()
{
#ifndef SVR4_SHARED_LIBS
struct minimal_symbol *msymbol;
CORE_ADDR address = 0;
char **symbolp;
/* For SunOS, we want to limit the search for the debug base symbol to the
executable being debugged, since there is a duplicate named symbol in the
shared library. We don't want the shared library versions. */
for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++)
{
msymbol = lookup_minimal_symbol (*symbolp, symfile_objfile);
if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
{
address = SYMBOL_VALUE_ADDRESS (msymbol);
return (address);
}
}
return (0);
#else /* SVR4_SHARED_LIBS */
/* Check to see if we have a currently valid address, and if so, avoid
doing all this work again and just return the cached address. If
we have no cached address, try to locate it in the dynamic info
section. */
if (debug_base == 0)
{
debug_base = elf_locate_base ();
}
return (debug_base);
#endif /* !SVR4_SHARED_LIBS */
}
/*
LOCAL FUNCTION
first_link_map_member -- locate first member in dynamic linker's map
SYNOPSIS
static struct link_map *first_link_map_member (void)
DESCRIPTION
Read in a copy of the first member in the inferior's dynamic
link map from the inferior's dynamic linker structures, and return
a pointer to the copy in our address space.
*/
static struct link_map *
first_link_map_member ()
{
struct link_map *lm = NULL;
#ifndef SVR4_SHARED_LIBS
read_memory (debug_base, (char *) &dynamic_copy, sizeof (dynamic_copy));
if (dynamic_copy.ld_version >= 2)
{
/* It is a version that we can deal with, so read in the secondary
structure and find the address of the link map list from it. */
read_memory ((CORE_ADDR) dynamic_copy.ld_un.ld_2, (char *) &ld_2_copy,
sizeof (struct link_dynamic_2));
lm = ld_2_copy.ld_loaded;
}
#else /* SVR4_SHARED_LIBS */
read_memory (debug_base, (char *) &debug_copy, sizeof (struct r_debug));
/* FIXME: Perhaps we should validate the info somehow, perhaps by
checking r_version for a known version number, or r_state for
RT_CONSISTENT. */
lm = debug_copy.r_map;
#endif /* !SVR4_SHARED_LIBS */
return (lm);
}
/*
LOCAL FUNCTION
find_solib -- step through list of shared objects
SYNOPSIS
struct so_list *find_solib (struct so_list *so_list_ptr)
DESCRIPTION
This module contains the routine which finds the names of any
loaded "images" in the current process. The argument in must be
NULL on the first call, and then the returned value must be passed
in on subsequent calls. This provides the capability to "step" down
the list of loaded objects. On the last object, a NULL value is
returned.
The arg and return value are "struct link_map" pointers, as defined
in <link.h>.
*/
static struct so_list *
find_solib (so_list_ptr)
struct so_list *so_list_ptr; /* Last lm or NULL for first one */
{
struct so_list *so_list_next = NULL;
struct link_map *lm = NULL;
struct so_list *new;
if (so_list_ptr == NULL)
{
/* We are setting up for a new scan through the loaded images. */
if ((so_list_next = so_list_head) == NULL)
{
/* We have not already read in the dynamic linking structures
from the inferior, lookup the address of the base structure. */
debug_base = locate_base ();
if (debug_base != 0)
{
/* Read the base structure in and find the address of the first
link map list member. */
lm = first_link_map_member ();
}
}
}
else
{
/* We have been called before, and are in the process of walking
the shared library list. Advance to the next shared object. */
if ((lm = LM_NEXT (so_list_ptr)) == NULL)
{
/* We have hit the end of the list, so check to see if any were
added, but be quiet if we can't read from the target any more. */
int status = target_read_memory ((CORE_ADDR) so_list_ptr -> lmaddr,
(char *) &(so_list_ptr -> lm),
sizeof (struct link_map));
if (status == 0)
{
lm = LM_NEXT (so_list_ptr);
}
else
{
lm = NULL;
}
}
so_list_next = so_list_ptr -> next;
}
if ((so_list_next == NULL) && (lm != NULL))
{
/* Get next link map structure from inferior image and build a local
abbreviated load_map structure */
new = (struct so_list *) xmalloc (sizeof (struct so_list));
memset ((char *) new, 0, sizeof (struct so_list));
new -> lmaddr = lm;
/* Add the new node as the next node in the list, or as the root
node if this is the first one. */
if (so_list_ptr != NULL)
{
so_list_ptr -> next = new;
}
else
{
so_list_head = new;
}
so_list_next = new;
read_memory ((CORE_ADDR) lm, (char *) &(new -> lm),
sizeof (struct link_map));
/* For SVR4 versions, the first entry in the link map is for the
inferior executable, so we must ignore it. For some versions of
SVR4, it has no name. For others (Solaris 2.3 for example), it
does have a name, so we can no longer use a missing name to
decide when to ignore it. */
if (!IGNORE_FIRST_LINK_MAP_ENTRY (new -> lm))
{
int errcode;
char *buffer;
target_read_string ((CORE_ADDR) LM_NAME (new), &buffer,
MAX_PATH_SIZE - 1, &errcode);
if (errcode != 0)
error ("find_solib: Can't read pathname for load map: %s\n",
safe_strerror (errcode));
strncpy (new -> so_name, buffer, MAX_PATH_SIZE - 1);
new -> so_name[MAX_PATH_SIZE - 1] = '\0';
free (buffer);
solib_map_sections (new);
}
}
return (so_list_next);
}
/* A small stub to get us past the arg-passing pinhole of catch_errors. */
static int
symbol_add_stub (arg)
char *arg;
{
register struct so_list *so = (struct so_list *) arg; /* catch_errs bogon */
so -> objfile = symbol_file_add (so -> so_name, so -> from_tty,
(unsigned int) so -> textsection -> addr,
0, 0, 0);
return (1);
}
/*
GLOBAL FUNCTION
solib_add -- add a shared library file to the symtab and section list
SYNOPSIS
void solib_add (char *arg_string, int from_tty,
struct target_ops *target)
DESCRIPTION
*/
void
solib_add (arg_string, from_tty, target)
char *arg_string;
int from_tty;
struct target_ops *target;
{
register struct so_list *so = NULL; /* link map state variable */
/* Last shared library that we read. */
struct so_list *so_last = NULL;
char *re_err;
int count;
int old;
if ((re_err = re_comp (arg_string ? arg_string : ".")) != NULL)
{
error ("Invalid regexp: %s", re_err);
}
/* Add the shared library sections to the section table of the
specified target, if any. We have to do this before reading the
symbol files as symbol_file_add calls reinit_frame_cache and
creating a new frame might access memory in the shared library. */
if (target)
{
/* Count how many new section_table entries there are. */
so = NULL;
count = 0;
while ((so = find_solib (so)) != NULL)
{
if (so -> so_name[0])
{
count += so -> sections_end - so -> sections;
}
}
if (count)
{
/* Reallocate the target's section table including the new size. */
if (target -> to_sections)
{
old = target -> to_sections_end - target -> to_sections;
target -> to_sections = (struct section_table *)
xrealloc ((char *)target -> to_sections,
(sizeof (struct section_table)) * (count + old));
}
else
{
old = 0;
target -> to_sections = (struct section_table *)
xmalloc ((sizeof (struct section_table)) * count);
}
target -> to_sections_end = target -> to_sections + (count + old);
/* Add these section table entries to the target's table. */
while ((so = find_solib (so)) != NULL)
{
if (so -> so_name[0])
{
count = so -> sections_end - so -> sections;
memcpy ((char *) (target -> to_sections + old),
so -> sections,
(sizeof (struct section_table)) * count);
old += count;
}
}
}
}
/* Now add the symbol files. */
while ((so = find_solib (so)) != NULL)
{
if (so -> so_name[0] && re_exec (so -> so_name))
{
so -> from_tty = from_tty;
if (so -> symbols_loaded)
{
if (from_tty)
{
printf_unfiltered ("Symbols already loaded for %s\n", so -> so_name);
}
}
else if (catch_errors
(symbol_add_stub, (char *) so,
"Error while reading shared library symbols:\n",
RETURN_MASK_ALL))
{
so_last = so;
so -> symbols_loaded = 1;
}
}
}
/* Calling this once at the end means that we put all the minimal
symbols for commons into the objfile for the last shared library.
Since they are in common, this should not be a problem. If we
delete the objfile with the minimal symbols, we can put all the
symbols into a new objfile (and will on the next call to solib_add).
An alternate approach would be to create an objfile just for
common minsyms, thus not needing any objfile argument to
solib_add_common_symbols. */
if (so_last)
special_symbol_handling (so_last);
}
/*
LOCAL FUNCTION
info_sharedlibrary_command -- code for "info sharedlibrary"
SYNOPSIS
static void info_sharedlibrary_command ()
DESCRIPTION
Walk through the shared library list and print information
about each attached library.
*/
static void
info_sharedlibrary_command (ignore, from_tty)
char *ignore;
int from_tty;
{
register struct so_list *so = NULL; /* link map state variable */
int header_done = 0;
if (exec_bfd == NULL)
{
printf_unfiltered ("No exec file.\n");
return;
}
while ((so = find_solib (so)) != NULL)
{
if (so -> so_name[0])
{
if (!header_done)
{
printf_unfiltered("%-12s%-12s%-12s%s\n", "From", "To", "Syms Read",
"Shared Object Library");
header_done++;
}
/* FIXME-32x64: need print_address_numeric with field width or
some such. */
printf_unfiltered ("%-12s",
local_hex_string_custom ((unsigned long) LM_ADDR (so),
"08l"));
printf_unfiltered ("%-12s",
local_hex_string_custom ((unsigned long) so -> lmend,
"08l"));
printf_unfiltered ("%-12s", so -> symbols_loaded ? "Yes" : "No");
printf_unfiltered ("%s\n", so -> so_name);
}
}
if (so_list_head == NULL)
{
printf_unfiltered ("No shared libraries loaded at this time.\n");
}
}
/*
GLOBAL FUNCTION
solib_address -- check to see if an address is in a shared lib
SYNOPSIS
int solib_address (CORE_ADDR address)
DESCRIPTION
Provides a hook for other gdb routines to discover whether or
not a particular address is within the mapped address space of
a shared library. Any address between the base mapping address
and the first address beyond the end of the last mapping, is
considered to be within the shared library address space, for
our purposes.
For example, this routine is called at one point to disable
breakpoints which are in shared libraries that are not currently
mapped in.
*/
int
solib_address (address)
CORE_ADDR address;
{
register struct so_list *so = 0; /* link map state variable */
while ((so = find_solib (so)) != NULL)
{
if (so -> so_name[0])
{
if ((address >= (CORE_ADDR) LM_ADDR (so)) &&
(address < (CORE_ADDR) so -> lmend))
{
return (1);
}
}
}
return (0);
}
/* Called by free_all_symtabs */
void
clear_solib()
{
struct so_list *next;
char *bfd_filename;
while (so_list_head)
{
if (so_list_head -> sections)
{
free ((PTR)so_list_head -> sections);
}
if (so_list_head -> abfd)
{
bfd_filename = bfd_get_filename (so_list_head -> abfd);
bfd_close (so_list_head -> abfd);
}
else
/* This happens for the executable on SVR4. */
bfd_filename = NULL;
next = so_list_head -> next;
if (bfd_filename)
free ((PTR)bfd_filename);
free ((PTR)so_list_head);
so_list_head = next;
}
debug_base = 0;
}
/*
LOCAL FUNCTION
disable_break -- remove the "mapping changed" breakpoint
SYNOPSIS
static int disable_break ()
DESCRIPTION
Removes the breakpoint that gets hit when the dynamic linker
completes a mapping change.
*/
static int
disable_break ()
{
int status = 1;
#ifndef SVR4_SHARED_LIBS
int in_debugger = 0;
/* Read the debugger structure from the inferior to retrieve the
address of the breakpoint and the original contents of the
breakpoint address. Remove the breakpoint by writing the original
contents back. */
read_memory (debug_addr, (char *) &debug_copy, sizeof (debug_copy));
/* Set `in_debugger' to zero now. */
write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger));
breakpoint_addr = (CORE_ADDR) debug_copy.ldd_bp_addr;
write_memory (breakpoint_addr, (char *) &debug_copy.ldd_bp_inst,
sizeof (debug_copy.ldd_bp_inst));
#else /* SVR4_SHARED_LIBS */
/* Note that breakpoint address and original contents are in our address
space, so we just need to write the original contents back. */
if (memory_remove_breakpoint (breakpoint_addr, shadow_contents) != 0)
{
status = 0;
}
#endif /* !SVR4_SHARED_LIBS */
/* For the SVR4 version, we always know the breakpoint address. For the
SunOS version we don't know it until the above code is executed.
Grumble if we are stopped anywhere besides the breakpoint address. */
if (stop_pc != breakpoint_addr)
{
warning ("stopped at unknown breakpoint while handling shared libraries");
}
return (status);
}
/*
LOCAL FUNCTION
enable_break -- arrange for dynamic linker to hit breakpoint
SYNOPSIS
int enable_break (void)
DESCRIPTION
Both the SunOS and the SVR4 dynamic linkers have, as part of their
debugger interface, support for arranging for the inferior to hit
a breakpoint after mapping in the shared libraries. This function
enables that breakpoint.
For SunOS, there is a special flag location (in_debugger) which we
set to 1. When the dynamic linker sees this flag set, it will set
a breakpoint at a location known only to itself, after saving the
original contents of that place and the breakpoint address itself,
in it's own internal structures. When we resume the inferior, it
will eventually take a SIGTRAP when it runs into the breakpoint.
We handle this (in a different place) by restoring the contents of
the breakpointed location (which is only known after it stops),
chasing around to locate the shared libraries that have been
loaded, then resuming.
For SVR4, the debugger interface structure contains a member (r_brk)
which is statically initialized at the time the shared library is
built, to the offset of a function (_r_debug_state) which is guaran-
teed to be called once before mapping in a library, and again when
the mapping is complete. At the time we are examining this member,
it contains only the unrelocated offset of the function, so we have
to do our own relocation. Later, when the dynamic linker actually
runs, it relocates r_brk to be the actual address of _r_debug_state().
The debugger interface structure also contains an enumeration which
is set to either RT_ADD or RT_DELETE prior to changing the mapping,
depending upon whether or not the library is being mapped or unmapped,
and then set to RT_CONSISTENT after the library is mapped/unmapped.
*/
static int
enable_break ()
{
int success = 0;
#ifndef SVR4_SHARED_LIBS
int j;
int in_debugger;
/* Get link_dynamic structure */
j = target_read_memory (debug_base, (char *) &dynamic_copy,
sizeof (dynamic_copy));
if (j)
{
/* unreadable */
return (0);
}
/* Calc address of debugger interface structure */
debug_addr = (CORE_ADDR) dynamic_copy.ldd;
/* Calc address of `in_debugger' member of debugger interface structure */
flag_addr = debug_addr + (CORE_ADDR) ((char *) &debug_copy.ldd_in_debugger -
(char *) &debug_copy);
/* Write a value of 1 to this member. */
in_debugger = 1;
write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger));
success = 1;
#else /* SVR4_SHARED_LIBS */
#ifdef BKPT_AT_SYMBOL
struct minimal_symbol *msymbol;
char **bkpt_namep;
CORE_ADDR bkpt_addr;
/* Scan through the list of symbols, trying to look up the symbol and
set a breakpoint there. Terminate loop when we/if we succeed. */
breakpoint_addr = 0;
for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
{
msymbol = lookup_minimal_symbol (*bkpt_namep, symfile_objfile);
if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
{
bkpt_addr = SYMBOL_VALUE_ADDRESS (msymbol);
if (target_insert_breakpoint (bkpt_addr, shadow_contents) == 0)
{
breakpoint_addr = bkpt_addr;
success = 1;
break;
}
}
}
#else /* !BKPT_AT_SYMBOL */
struct symtab_and_line sal;
/* Read the debugger interface structure directly. */
read_memory (debug_base, (char *) &debug_copy, sizeof (debug_copy));
/* Set breakpoint at the debugger interface stub routine that will
be called just prior to each mapping change and again after the
mapping change is complete. Set up the (nonexistent) handler to
deal with hitting these breakpoints. (FIXME). */
warning ("'%s': line %d: missing SVR4 support code", __FILE__, __LINE__);
success = 1;
#endif /* BKPT_AT_SYMBOL */
#endif /* !SVR4_SHARED_LIBS */
return (success);
}
/*
GLOBAL FUNCTION
solib_create_inferior_hook -- shared library startup support
SYNOPSIS
void solib_create_inferior_hook()
DESCRIPTION
When gdb starts up the inferior, it nurses it along (through the
shell) until it is ready to execute it's first instruction. At this
point, this function gets called via expansion of the macro
SOLIB_CREATE_INFERIOR_HOOK.
For SunOS executables, this first instruction is typically the
one at "_start", or a similar text label, regardless of whether
the executable is statically or dynamically linked. The runtime
startup code takes care of dynamically linking in any shared
libraries, once gdb allows the inferior to continue.
For SVR4 executables, this first instruction is either the first
instruction in the dynamic linker (for dynamically linked
executables) or the instruction at "start" for statically linked
executables. For dynamically linked executables, the system
first exec's /lib/libc.so.N, which contains the dynamic linker,
and starts it running. The dynamic linker maps in any needed
shared libraries, maps in the actual user executable, and then
jumps to "start" in the user executable.
For both SunOS shared libraries, and SVR4 shared libraries, we
can arrange to cooperate with the dynamic linker to discover the
names of shared libraries that are dynamically linked, and the
base addresses to which they are linked.
This function is responsible for discovering those names and
addresses, and saving sufficient information about them to allow
their symbols to be read at a later time.
FIXME
Between enable_break() and disable_break(), this code does not
properly handle hitting breakpoints which the user might have
set in the startup code or in the dynamic linker itself. Proper
handling will probably have to wait until the implementation is
changed to use the "breakpoint handler function" method.
Also, what if child has exit()ed? Must exit loop somehow.
*/
void
solib_create_inferior_hook()
{
/* If we are using the BKPT_AT_SYMBOL code, then we don't need the base
yet. In fact, in the case of a SunOS4 executable being run on
Solaris, we can't get it yet. find_solib will get it when it needs
it. */
#if !(defined (SVR4_SHARED_LIBS) && defined (BKPT_AT_SYMBOL))
if ((debug_base = locate_base ()) == 0)
{
/* Can't find the symbol or the executable is statically linked. */
return;
}
#endif
if (!enable_break ())
{
warning ("shared library handler failed to enable breakpoint");
return;
}
/* Now run the target. It will eventually hit the breakpoint, at
which point all of the libraries will have been mapped in and we
can go groveling around in the dynamic linker structures to find
out what we need to know about them. */
clear_proceed_status ();
stop_soon_quietly = 1;
stop_signal = TARGET_SIGNAL_0;
do
{
target_resume (-1, 0, stop_signal);
wait_for_inferior ();
}
while (stop_signal != TARGET_SIGNAL_TRAP);
stop_soon_quietly = 0;
/* We are now either at the "mapping complete" breakpoint (or somewhere
else, a condition we aren't prepared to deal with anyway), so adjust
the PC as necessary after a breakpoint, disable the breakpoint, and
add any shared libraries that were mapped in. */
if (DECR_PC_AFTER_BREAK)
{
stop_pc -= DECR_PC_AFTER_BREAK;
write_register (PC_REGNUM, stop_pc);
}
if (!disable_break ())
{
warning ("shared library handler failed to disable breakpoint");
}
solib_add ((char *) 0, 0, (struct target_ops *) 0);
}
/*
LOCAL FUNCTION
special_symbol_handling -- additional shared library symbol handling
SYNOPSIS
void special_symbol_handling (struct so_list *so)
DESCRIPTION
Once the symbols from a shared object have been loaded in the usual
way, we are called to do any system specific symbol handling that
is needed.
For Suns, this consists of grunging around in the dynamic linkers
structures to find symbol definitions for "common" symbols and
adding them to the minimal symbol table for the corresponding
objfile.
*/
static void
special_symbol_handling (so)
struct so_list *so;
{
#ifndef SVR4_SHARED_LIBS
int j;
if (debug_addr == 0)
{
/* Get link_dynamic structure */
j = target_read_memory (debug_base, (char *) &dynamic_copy,
sizeof (dynamic_copy));
if (j)
{
/* unreadable */
return;
}
/* Calc address of debugger interface structure */
/* FIXME, this needs work for cross-debugging of core files
(byteorder, size, alignment, etc). */
debug_addr = (CORE_ADDR) dynamic_copy.ldd;
}
/* Read the debugger structure from the inferior, just to make sure
we have a current copy. */
j = target_read_memory (debug_addr, (char *) &debug_copy,
sizeof (debug_copy));
if (j)
return; /* unreadable */
/* Get common symbol definitions for the loaded object. */
if (debug_copy.ldd_cp)
{
solib_add_common_symbols (debug_copy.ldd_cp, so -> objfile);
}
#endif /* !SVR4_SHARED_LIBS */
}
/*
LOCAL FUNCTION
sharedlibrary_command -- handle command to explicitly add library
SYNOPSIS
static void sharedlibrary_command (char *args, int from_tty)
DESCRIPTION
*/
static void
sharedlibrary_command (args, from_tty)
char *args;
int from_tty;
{
dont_repeat ();
solib_add (args, from_tty, (struct target_ops *) 0);
}
void
_initialize_solib()
{
add_com ("sharedlibrary", class_files, sharedlibrary_command,
"Load shared object library symbols for files matching REGEXP.");
add_info ("sharedlibrary", info_sharedlibrary_command,
"Status of loaded shared object libraries.");
}
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