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- /* Handle TIC6X (DSBT) shared libraries for GDB, the GNU Debugger.
- Copyright (C) 2010-2022 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 3 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, see <http://www.gnu.org/licenses/>. */
- #include "defs.h"
- #include "inferior.h"
- #include "gdbcore.h"
- #include "solib.h"
- #include "solist.h"
- #include "objfiles.h"
- #include "symtab.h"
- #include "language.h"
- #include "command.h"
- #include "gdbcmd.h"
- #include "elf-bfd.h"
- #include "gdb_bfd.h"
- #define GOT_MODULE_OFFSET 4
- /* Flag which indicates whether internal debug messages should be printed. */
- static unsigned int solib_dsbt_debug = 0;
- /* TIC6X pointers are four bytes wide. */
- enum { TIC6X_PTR_SIZE = 4 };
- /* Representation of loadmap and related structs for the TIC6X DSBT. */
- /* External versions; the size and alignment of the fields should be
- the same as those on the target. When loaded, the placement of
- the bits in each field will be the same as on the target. */
- typedef gdb_byte ext_Elf32_Half[2];
- typedef gdb_byte ext_Elf32_Addr[4];
- typedef gdb_byte ext_Elf32_Word[4];
- struct ext_elf32_dsbt_loadseg
- {
- /* Core address to which the segment is mapped. */
- ext_Elf32_Addr addr;
- /* VMA recorded in the program header. */
- ext_Elf32_Addr p_vaddr;
- /* Size of this segment in memory. */
- ext_Elf32_Word p_memsz;
- };
- struct ext_elf32_dsbt_loadmap {
- /* Protocol version number, must be zero. */
- ext_Elf32_Word version;
- /* A pointer to the DSBT table; the DSBT size and the index of this
- module. */
- ext_Elf32_Word dsbt_table_ptr;
- ext_Elf32_Word dsbt_size;
- ext_Elf32_Word dsbt_index;
- /* Number of segments in this map. */
- ext_Elf32_Word nsegs;
- /* The actual memory map. */
- struct ext_elf32_dsbt_loadseg segs[1 /* nsegs, actually */];
- };
- /* Internal versions; the types are GDB types and the data in each
- of the fields is (or will be) decoded from the external struct
- for ease of consumption. */
- struct int_elf32_dsbt_loadseg
- {
- /* Core address to which the segment is mapped. */
- CORE_ADDR addr;
- /* VMA recorded in the program header. */
- CORE_ADDR p_vaddr;
- /* Size of this segment in memory. */
- long p_memsz;
- };
- struct int_elf32_dsbt_loadmap
- {
- /* Protocol version number, must be zero. */
- int version;
- CORE_ADDR dsbt_table_ptr;
- /* A pointer to the DSBT table; the DSBT size and the index of this
- module. */
- int dsbt_size, dsbt_index;
- /* Number of segments in this map. */
- int nsegs;
- /* The actual memory map. */
- struct int_elf32_dsbt_loadseg segs[1 /* nsegs, actually */];
- };
- /* External link_map and elf32_dsbt_loadaddr struct definitions. */
- typedef gdb_byte ext_ptr[4];
- struct ext_elf32_dsbt_loadaddr
- {
- ext_ptr map; /* struct elf32_dsbt_loadmap *map; */
- };
- struct ext_link_map
- {
- struct ext_elf32_dsbt_loadaddr l_addr;
- /* Absolute file name object was found in. */
- ext_ptr l_name; /* char *l_name; */
- /* Dynamic section of the shared object. */
- ext_ptr l_ld; /* ElfW(Dyn) *l_ld; */
- /* Chain of loaded objects. */
- ext_ptr l_next, l_prev; /* struct link_map *l_next, *l_prev; */
- };
- /* Link map info to include in an allocated so_list entry */
- struct lm_info_dsbt : public lm_info_base
- {
- ~lm_info_dsbt ()
- {
- xfree (this->map);
- }
- /* The loadmap, digested into an easier to use form. */
- int_elf32_dsbt_loadmap *map = NULL;
- };
- /* Per pspace dsbt specific data. */
- struct dsbt_info
- {
- /* The load map, got value, etc. are not available from the chain
- of loaded shared objects. ``main_executable_lm_info'' provides
- a way to get at this information so that it doesn't need to be
- frequently recomputed. Initialized by dsbt_relocate_main_executable. */
- struct lm_info_dsbt *main_executable_lm_info = nullptr;
- /* Load maps for the main executable and the interpreter. These are obtained
- from ptrace. They are the starting point for getting into the program,
- and are required to find the solib list with the individual load maps for
- each module. */
- struct int_elf32_dsbt_loadmap *exec_loadmap = nullptr;
- struct int_elf32_dsbt_loadmap *interp_loadmap = nullptr;
- /* Cached value for lm_base, below. */
- CORE_ADDR lm_base_cache = 0;
- /* Link map address for main module. */
- CORE_ADDR main_lm_addr = 0;
- CORE_ADDR interp_text_sect_low = 0;
- CORE_ADDR interp_text_sect_high = 0;
- CORE_ADDR interp_plt_sect_low = 0;
- CORE_ADDR interp_plt_sect_high = 0;
- };
- /* Per-program-space data key. */
- static program_space_key<dsbt_info> solib_dsbt_pspace_data;
- /* Get the current dsbt data. If none is found yet, add it now. This
- function always returns a valid object. */
- static struct dsbt_info *
- get_dsbt_info (void)
- {
- struct dsbt_info *info;
- info = solib_dsbt_pspace_data.get (current_program_space);
- if (info != NULL)
- return info;
- return solib_dsbt_pspace_data.emplace (current_program_space);
- }
- static void
- dsbt_print_loadmap (struct int_elf32_dsbt_loadmap *map)
- {
- int i;
- if (map == NULL)
- gdb_printf ("(null)\n");
- else if (map->version != 0)
- gdb_printf (_("Unsupported map version: %d\n"), map->version);
- else
- {
- gdb_printf ("version %d\n", map->version);
- for (i = 0; i < map->nsegs; i++)
- gdb_printf ("%s:%s -> %s:%s\n",
- print_core_address (target_gdbarch (),
- map->segs[i].p_vaddr),
- print_core_address (target_gdbarch (),
- map->segs[i].p_vaddr
- + map->segs[i].p_memsz),
- print_core_address (target_gdbarch (), map->segs[i].addr),
- print_core_address (target_gdbarch (), map->segs[i].addr
- + map->segs[i].p_memsz));
- }
- }
- /* Decode int_elf32_dsbt_loadmap from BUF. */
- static struct int_elf32_dsbt_loadmap *
- decode_loadmap (const gdb_byte *buf)
- {
- enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
- const struct ext_elf32_dsbt_loadmap *ext_ldmbuf;
- struct int_elf32_dsbt_loadmap *int_ldmbuf;
- int version, seg, nsegs;
- int int_ldmbuf_size;
- ext_ldmbuf = (struct ext_elf32_dsbt_loadmap *) buf;
- /* Extract the version. */
- version = extract_unsigned_integer (ext_ldmbuf->version,
- sizeof ext_ldmbuf->version,
- byte_order);
- if (version != 0)
- {
- /* We only handle version 0. */
- return NULL;
- }
- /* Extract the number of segments. */
- nsegs = extract_unsigned_integer (ext_ldmbuf->nsegs,
- sizeof ext_ldmbuf->nsegs,
- byte_order);
- if (nsegs <= 0)
- return NULL;
- /* Allocate space into which to put information extract from the
- external loadsegs. I.e, allocate the internal loadsegs. */
- int_ldmbuf_size = (sizeof (struct int_elf32_dsbt_loadmap)
- + (nsegs - 1) * sizeof (struct int_elf32_dsbt_loadseg));
- int_ldmbuf = (struct int_elf32_dsbt_loadmap *) xmalloc (int_ldmbuf_size);
- /* Place extracted information in internal structs. */
- int_ldmbuf->version = version;
- int_ldmbuf->nsegs = nsegs;
- for (seg = 0; seg < nsegs; seg++)
- {
- int_ldmbuf->segs[seg].addr
- = extract_unsigned_integer (ext_ldmbuf->segs[seg].addr,
- sizeof (ext_ldmbuf->segs[seg].addr),
- byte_order);
- int_ldmbuf->segs[seg].p_vaddr
- = extract_unsigned_integer (ext_ldmbuf->segs[seg].p_vaddr,
- sizeof (ext_ldmbuf->segs[seg].p_vaddr),
- byte_order);
- int_ldmbuf->segs[seg].p_memsz
- = extract_unsigned_integer (ext_ldmbuf->segs[seg].p_memsz,
- sizeof (ext_ldmbuf->segs[seg].p_memsz),
- byte_order);
- }
- return int_ldmbuf;
- }
- static struct dsbt_info *get_dsbt_info (void);
- /* Interrogate the Linux kernel to find out where the program was loaded.
- There are two load maps; one for the executable and one for the
- interpreter (only in the case of a dynamically linked executable). */
- static void
- dsbt_get_initial_loadmaps (void)
- {
- struct dsbt_info *info = get_dsbt_info ();
- gdb::optional<gdb::byte_vector> buf
- = target_read_alloc (current_inferior ()->top_target (),
- TARGET_OBJECT_FDPIC, "exec");
- if (!buf || buf->empty ())
- {
- info->exec_loadmap = NULL;
- error (_("Error reading DSBT exec loadmap"));
- }
- info->exec_loadmap = decode_loadmap (buf->data ());
- if (solib_dsbt_debug)
- dsbt_print_loadmap (info->exec_loadmap);
- buf = target_read_alloc (current_inferior ()->top_target (),
- TARGET_OBJECT_FDPIC, "exec");
- if (!buf || buf->empty ())
- {
- info->interp_loadmap = NULL;
- error (_("Error reading DSBT interp loadmap"));
- }
- info->interp_loadmap = decode_loadmap (buf->data ());
- if (solib_dsbt_debug)
- dsbt_print_loadmap (info->interp_loadmap);
- }
- /* Given address LDMADDR, fetch and decode the loadmap at that address.
- Return NULL if there is a problem reading the target memory or if
- there doesn't appear to be a loadmap at the given address. The
- allocated space (representing the loadmap) returned by this
- function may be freed via a single call to xfree. */
- static struct int_elf32_dsbt_loadmap *
- fetch_loadmap (CORE_ADDR ldmaddr)
- {
- enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
- struct ext_elf32_dsbt_loadmap ext_ldmbuf_partial;
- struct ext_elf32_dsbt_loadmap *ext_ldmbuf;
- struct int_elf32_dsbt_loadmap *int_ldmbuf;
- int ext_ldmbuf_size, int_ldmbuf_size;
- int version, seg, nsegs;
- /* Fetch initial portion of the loadmap. */
- if (target_read_memory (ldmaddr, (gdb_byte *) &ext_ldmbuf_partial,
- sizeof ext_ldmbuf_partial))
- {
- /* Problem reading the target's memory. */
- return NULL;
- }
- /* Extract the version. */
- version = extract_unsigned_integer (ext_ldmbuf_partial.version,
- sizeof ext_ldmbuf_partial.version,
- byte_order);
- if (version != 0)
- {
- /* We only handle version 0. */
- return NULL;
- }
- /* Extract the number of segments. */
- nsegs = extract_unsigned_integer (ext_ldmbuf_partial.nsegs,
- sizeof ext_ldmbuf_partial.nsegs,
- byte_order);
- if (nsegs <= 0)
- return NULL;
- /* Allocate space for the complete (external) loadmap. */
- ext_ldmbuf_size = sizeof (struct ext_elf32_dsbt_loadmap)
- + (nsegs - 1) * sizeof (struct ext_elf32_dsbt_loadseg);
- ext_ldmbuf = (struct ext_elf32_dsbt_loadmap *) xmalloc (ext_ldmbuf_size);
- /* Copy over the portion of the loadmap that's already been read. */
- memcpy (ext_ldmbuf, &ext_ldmbuf_partial, sizeof ext_ldmbuf_partial);
- /* Read the rest of the loadmap from the target. */
- if (target_read_memory (ldmaddr + sizeof ext_ldmbuf_partial,
- (gdb_byte *) ext_ldmbuf + sizeof ext_ldmbuf_partial,
- ext_ldmbuf_size - sizeof ext_ldmbuf_partial))
- {
- /* Couldn't read rest of the loadmap. */
- xfree (ext_ldmbuf);
- return NULL;
- }
- /* Allocate space into which to put information extract from the
- external loadsegs. I.e, allocate the internal loadsegs. */
- int_ldmbuf_size = sizeof (struct int_elf32_dsbt_loadmap)
- + (nsegs - 1) * sizeof (struct int_elf32_dsbt_loadseg);
- int_ldmbuf = (struct int_elf32_dsbt_loadmap *) xmalloc (int_ldmbuf_size);
- /* Place extracted information in internal structs. */
- int_ldmbuf->version = version;
- int_ldmbuf->nsegs = nsegs;
- for (seg = 0; seg < nsegs; seg++)
- {
- int_ldmbuf->segs[seg].addr
- = extract_unsigned_integer (ext_ldmbuf->segs[seg].addr,
- sizeof (ext_ldmbuf->segs[seg].addr),
- byte_order);
- int_ldmbuf->segs[seg].p_vaddr
- = extract_unsigned_integer (ext_ldmbuf->segs[seg].p_vaddr,
- sizeof (ext_ldmbuf->segs[seg].p_vaddr),
- byte_order);
- int_ldmbuf->segs[seg].p_memsz
- = extract_unsigned_integer (ext_ldmbuf->segs[seg].p_memsz,
- sizeof (ext_ldmbuf->segs[seg].p_memsz),
- byte_order);
- }
- xfree (ext_ldmbuf);
- return int_ldmbuf;
- }
- static void dsbt_relocate_main_executable (void);
- static int enable_break (void);
- /* See solist.h. */
- static int
- open_symbol_file_object (int from_tty)
- {
- /* Unimplemented. */
- return 0;
- }
- /* Given a loadmap and an address, return the displacement needed
- to relocate the address. */
- static CORE_ADDR
- displacement_from_map (struct int_elf32_dsbt_loadmap *map,
- CORE_ADDR addr)
- {
- int seg;
- for (seg = 0; seg < map->nsegs; seg++)
- if (map->segs[seg].p_vaddr <= addr
- && addr < map->segs[seg].p_vaddr + map->segs[seg].p_memsz)
- return map->segs[seg].addr - map->segs[seg].p_vaddr;
- return 0;
- }
- /* Return the address from which the link map chain may be found. On
- DSBT, a pointer to the start of the link map will be located at the
- word found at base of GOT + GOT_MODULE_OFFSET.
- The base of GOT may be found in a number of ways. Assuming that the
- main executable has already been relocated,
- 1 The easiest way to find this value is to look up the address of
- _GLOBAL_OFFSET_TABLE_.
- 2 The other way is to look for tag DT_PLTGOT, which contains the virtual
- address of Global Offset Table. .*/
- static CORE_ADDR
- lm_base (void)
- {
- enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
- struct bound_minimal_symbol got_sym;
- CORE_ADDR addr;
- gdb_byte buf[TIC6X_PTR_SIZE];
- struct dsbt_info *info = get_dsbt_info ();
- /* One of our assumptions is that the main executable has been relocated.
- Bail out if this has not happened. (Note that post_create_inferior
- in infcmd.c will call solib_add prior to solib_create_inferior_hook.
- If we allow this to happen, lm_base_cache will be initialized with
- a bogus value. */
- if (info->main_executable_lm_info == 0)
- return 0;
- /* If we already have a cached value, return it. */
- if (info->lm_base_cache)
- return info->lm_base_cache;
- got_sym = lookup_minimal_symbol ("_GLOBAL_OFFSET_TABLE_", NULL,
- current_program_space->symfile_object_file);
- if (got_sym.minsym != 0)
- {
- addr = BMSYMBOL_VALUE_ADDRESS (got_sym);
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "lm_base: get addr %x by _GLOBAL_OFFSET_TABLE_.\n",
- (unsigned int) addr);
- }
- else if (gdb_bfd_scan_elf_dyntag (DT_PLTGOT,
- current_program_space->exec_bfd (),
- &addr, NULL))
- {
- struct int_elf32_dsbt_loadmap *ldm;
- dsbt_get_initial_loadmaps ();
- ldm = info->exec_loadmap;
- addr += displacement_from_map (ldm, addr);
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "lm_base: get addr %x by DT_PLTGOT.\n",
- (unsigned int) addr);
- }
- else
- {
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "lm_base: _GLOBAL_OFFSET_TABLE_ not found.\n");
- return 0;
- }
- addr += GOT_MODULE_OFFSET;
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "lm_base: _GLOBAL_OFFSET_TABLE_ + %d = %s\n",
- GOT_MODULE_OFFSET, hex_string_custom (addr, 8));
- if (target_read_memory (addr, buf, sizeof buf) != 0)
- return 0;
- info->lm_base_cache = extract_unsigned_integer (buf, sizeof buf, byte_order);
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "lm_base: lm_base_cache = %s\n",
- hex_string_custom (info->lm_base_cache, 8));
- return info->lm_base_cache;
- }
- /* Build a list of `struct so_list' objects describing the shared
- objects currently loaded in the inferior. This list does not
- include an entry for the main executable file.
- Note that we only gather information directly available from the
- inferior --- we don't examine any of the shared library files
- themselves. The declaration of `struct so_list' says which fields
- we provide values for. */
- static struct so_list *
- dsbt_current_sos (void)
- {
- enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
- CORE_ADDR lm_addr;
- struct so_list *sos_head = NULL;
- struct so_list **sos_next_ptr = &sos_head;
- struct dsbt_info *info = get_dsbt_info ();
- /* Make sure that the main executable has been relocated. This is
- required in order to find the address of the global offset table,
- which in turn is used to find the link map info. (See lm_base
- for details.)
- Note that the relocation of the main executable is also performed
- by solib_create_inferior_hook, however, in the case of core
- files, this hook is called too late in order to be of benefit to
- solib_add. solib_add eventually calls this function,
- dsbt_current_sos, and also precedes the call to
- solib_create_inferior_hook. (See post_create_inferior in
- infcmd.c.) */
- if (info->main_executable_lm_info == 0 && core_bfd != NULL)
- dsbt_relocate_main_executable ();
- /* Locate the address of the first link map struct. */
- lm_addr = lm_base ();
- /* We have at least one link map entry. Fetch the lot of them,
- building the solist chain. */
- while (lm_addr)
- {
- struct ext_link_map lm_buf;
- ext_Elf32_Word indexword;
- CORE_ADDR map_addr;
- int dsbt_index;
- int ret;
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "current_sos: reading link_map entry at %s\n",
- hex_string_custom (lm_addr, 8));
- ret = target_read_memory (lm_addr, (gdb_byte *) &lm_buf, sizeof (lm_buf));
- if (ret)
- {
- warning (_("dsbt_current_sos: Unable to read link map entry."
- " Shared object chain may be incomplete."));
- break;
- }
- /* Fetch the load map address. */
- map_addr = extract_unsigned_integer (lm_buf.l_addr.map,
- sizeof lm_buf.l_addr.map,
- byte_order);
- ret = target_read_memory (map_addr + 12, (gdb_byte *) &indexword,
- sizeof indexword);
- if (ret)
- {
- warning (_("dsbt_current_sos: Unable to read dsbt index."
- " Shared object chain may be incomplete."));
- break;
- }
- dsbt_index = extract_unsigned_integer (indexword, sizeof indexword,
- byte_order);
- /* If the DSBT index is zero, then we're looking at the entry
- for the main executable. By convention, we don't include
- this in the list of shared objects. */
- if (dsbt_index != 0)
- {
- struct int_elf32_dsbt_loadmap *loadmap;
- struct so_list *sop;
- CORE_ADDR addr;
- loadmap = fetch_loadmap (map_addr);
- if (loadmap == NULL)
- {
- warning (_("dsbt_current_sos: Unable to fetch load map."
- " Shared object chain may be incomplete."));
- break;
- }
- sop = XCNEW (struct so_list);
- lm_info_dsbt *li = new lm_info_dsbt;
- sop->lm_info = li;
- li->map = loadmap;
- /* Fetch the name. */
- addr = extract_unsigned_integer (lm_buf.l_name,
- sizeof (lm_buf.l_name),
- byte_order);
- gdb::unique_xmalloc_ptr<char> name_buf
- = target_read_string (addr, SO_NAME_MAX_PATH_SIZE - 1);
- if (name_buf == nullptr)
- warning (_("Can't read pathname for link map entry."));
- else
- {
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog, "current_sos: name = %s\n",
- name_buf.get ());
- strncpy (sop->so_name, name_buf.get (), SO_NAME_MAX_PATH_SIZE - 1);
- sop->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
- strcpy (sop->so_original_name, sop->so_name);
- }
- *sos_next_ptr = sop;
- sos_next_ptr = &sop->next;
- }
- else
- {
- info->main_lm_addr = lm_addr;
- }
- lm_addr = extract_unsigned_integer (lm_buf.l_next,
- sizeof (lm_buf.l_next), byte_order);
- }
- return sos_head;
- }
- /* Return 1 if PC lies in the dynamic symbol resolution code of the
- run time loader. */
- static int
- dsbt_in_dynsym_resolve_code (CORE_ADDR pc)
- {
- struct dsbt_info *info = get_dsbt_info ();
- return ((pc >= info->interp_text_sect_low && pc < info->interp_text_sect_high)
- || (pc >= info->interp_plt_sect_low && pc < info->interp_plt_sect_high)
- || in_plt_section (pc));
- }
- /* Print a warning about being unable to set the dynamic linker
- breakpoint. */
- static void
- enable_break_failure_warning (void)
- {
- warning (_("Unable to find dynamic linker breakpoint function.\n"
- "GDB will be unable to debug shared library initializers\n"
- "and track explicitly loaded dynamic code."));
- }
- /* Helper function for gdb_bfd_lookup_symbol. */
- static int
- cmp_name (const asymbol *sym, const void *data)
- {
- return (strcmp (sym->name, (const char *) data) == 0);
- }
- /* The dynamic linkers has, as part of its debugger interface, support
- for arranging for the inferior to hit a breakpoint after mapping in
- the shared libraries. This function enables that breakpoint.
- On the TIC6X, using the shared library (DSBT), GDB can try to place
- a breakpoint on '_dl_debug_state' to monitor the shared library
- event. */
- static int
- enable_break (void)
- {
- asection *interp_sect;
- struct dsbt_info *info;
- if (current_program_space->exec_bfd () == NULL)
- return 0;
- if (!target_has_execution ())
- return 0;
- info = get_dsbt_info ();
- info->interp_text_sect_low = 0;
- info->interp_text_sect_high = 0;
- info->interp_plt_sect_low = 0;
- info->interp_plt_sect_high = 0;
- /* Find the .interp section; if not found, warn the user and drop
- into the old breakpoint at symbol code. */
- interp_sect = bfd_get_section_by_name (current_program_space->exec_bfd (),
- ".interp");
- if (interp_sect)
- {
- unsigned int interp_sect_size;
- char *buf;
- CORE_ADDR addr;
- struct int_elf32_dsbt_loadmap *ldm;
- int ret;
- /* Read the contents of the .interp section into a local buffer;
- the contents specify the dynamic linker this program uses. */
- interp_sect_size = bfd_section_size (interp_sect);
- buf = (char *) alloca (interp_sect_size);
- bfd_get_section_contents (current_program_space->exec_bfd (),
- interp_sect, buf, 0, interp_sect_size);
- /* Now we need to figure out where the dynamic linker was
- loaded so that we can load its symbols and place a breakpoint
- in the dynamic linker itself. */
- gdb_bfd_ref_ptr tmp_bfd;
- try
- {
- tmp_bfd = solib_bfd_open (buf);
- }
- catch (const gdb_exception &ex)
- {
- }
- if (tmp_bfd == NULL)
- {
- enable_break_failure_warning ();
- return 0;
- }
- dsbt_get_initial_loadmaps ();
- ldm = info->interp_loadmap;
- /* Record the relocated start and end address of the dynamic linker
- text and plt section for dsbt_in_dynsym_resolve_code. */
- interp_sect = bfd_get_section_by_name (tmp_bfd.get (), ".text");
- if (interp_sect)
- {
- info->interp_text_sect_low = bfd_section_vma (interp_sect);
- info->interp_text_sect_low
- += displacement_from_map (ldm, info->interp_text_sect_low);
- info->interp_text_sect_high
- = info->interp_text_sect_low + bfd_section_size (interp_sect);
- }
- interp_sect = bfd_get_section_by_name (tmp_bfd.get (), ".plt");
- if (interp_sect)
- {
- info->interp_plt_sect_low = bfd_section_vma (interp_sect);
- info->interp_plt_sect_low
- += displacement_from_map (ldm, info->interp_plt_sect_low);
- info->interp_plt_sect_high
- = info->interp_plt_sect_low + bfd_section_size (interp_sect);
- }
- addr = gdb_bfd_lookup_symbol (tmp_bfd.get (), cmp_name,
- "_dl_debug_state");
- if (addr != 0)
- {
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "enable_break: _dl_debug_state (prior to relocation) = %s\n",
- hex_string_custom (addr, 8));
- addr += displacement_from_map (ldm, addr);
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "enable_break: _dl_debug_state (after relocation) = %s\n",
- hex_string_custom (addr, 8));
- /* Now (finally!) create the solib breakpoint. */
- create_solib_event_breakpoint (target_gdbarch (), addr);
- ret = 1;
- }
- else
- {
- if (solib_dsbt_debug)
- gdb_printf (gdb_stdlog,
- "enable_break: _dl_debug_state is not found\n");
- ret = 0;
- }
- /* We're done with the loadmap. */
- xfree (ldm);
- return ret;
- }
- /* Tell the user we couldn't set a dynamic linker breakpoint. */
- enable_break_failure_warning ();
- /* Failure return. */
- return 0;
- }
- static void
- dsbt_relocate_main_executable (void)
- {
- struct int_elf32_dsbt_loadmap *ldm;
- int changed;
- struct obj_section *osect;
- struct dsbt_info *info = get_dsbt_info ();
- dsbt_get_initial_loadmaps ();
- ldm = info->exec_loadmap;
- delete info->main_executable_lm_info;
- info->main_executable_lm_info = new lm_info_dsbt;
- info->main_executable_lm_info->map = ldm;
- objfile *objf = current_program_space->symfile_object_file;
- section_offsets new_offsets (objf->section_offsets.size ());
- changed = 0;
- ALL_OBJFILE_OSECTIONS (objf, osect)
- {
- CORE_ADDR orig_addr, addr, offset;
- int osect_idx;
- int seg;
- osect_idx = osect - objf->sections;
- /* Current address of section. */
- addr = osect->addr ();
- /* Offset from where this section started. */
- offset = objf->section_offsets[osect_idx];
- /* Original address prior to any past relocations. */
- orig_addr = addr - offset;
- for (seg = 0; seg < ldm->nsegs; seg++)
- {
- if (ldm->segs[seg].p_vaddr <= orig_addr
- && orig_addr < ldm->segs[seg].p_vaddr + ldm->segs[seg].p_memsz)
- {
- new_offsets[osect_idx]
- = ldm->segs[seg].addr - ldm->segs[seg].p_vaddr;
- if (new_offsets[osect_idx] != offset)
- changed = 1;
- break;
- }
- }
- }
- if (changed)
- objfile_relocate (objf, new_offsets);
- /* Now that OBJF has been relocated, we can compute the GOT value
- and stash it away. */
- }
- /* 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 solib_create_inferior_hook.
- For the DSBT shared library, the main executable needs to be relocated.
- The shared library breakpoints also need to be enabled. */
- static void
- dsbt_solib_create_inferior_hook (int from_tty)
- {
- /* Relocate main executable. */
- dsbt_relocate_main_executable ();
- /* Enable shared library breakpoints. */
- if (!enable_break ())
- {
- warning (_("shared library handler failed to enable breakpoint"));
- return;
- }
- }
- static void
- dsbt_clear_solib (void)
- {
- struct dsbt_info *info = get_dsbt_info ();
- info->lm_base_cache = 0;
- info->main_lm_addr = 0;
- delete info->main_executable_lm_info;
- info->main_executable_lm_info = NULL;
- }
- static void
- dsbt_free_so (struct so_list *so)
- {
- lm_info_dsbt *li = (lm_info_dsbt *) so->lm_info;
- delete li;
- }
- static void
- dsbt_relocate_section_addresses (struct so_list *so,
- struct target_section *sec)
- {
- int seg;
- lm_info_dsbt *li = (lm_info_dsbt *) so->lm_info;
- int_elf32_dsbt_loadmap *map = li->map;
- for (seg = 0; seg < map->nsegs; seg++)
- {
- if (map->segs[seg].p_vaddr <= sec->addr
- && sec->addr < map->segs[seg].p_vaddr + map->segs[seg].p_memsz)
- {
- CORE_ADDR displ = map->segs[seg].addr - map->segs[seg].p_vaddr;
- sec->addr += displ;
- sec->endaddr += displ;
- break;
- }
- }
- }
- static void
- show_dsbt_debug (struct ui_file *file, int from_tty,
- struct cmd_list_element *c, const char *value)
- {
- gdb_printf (file, _("solib-dsbt debugging is %s.\n"), value);
- }
- struct target_so_ops dsbt_so_ops;
- void _initialize_dsbt_solib ();
- void
- _initialize_dsbt_solib ()
- {
- dsbt_so_ops.relocate_section_addresses = dsbt_relocate_section_addresses;
- dsbt_so_ops.free_so = dsbt_free_so;
- dsbt_so_ops.clear_solib = dsbt_clear_solib;
- dsbt_so_ops.solib_create_inferior_hook = dsbt_solib_create_inferior_hook;
- dsbt_so_ops.current_sos = dsbt_current_sos;
- dsbt_so_ops.open_symbol_file_object = open_symbol_file_object;
- dsbt_so_ops.in_dynsym_resolve_code = dsbt_in_dynsym_resolve_code;
- dsbt_so_ops.bfd_open = solib_bfd_open;
- /* Debug this file's internals. */
- add_setshow_zuinteger_cmd ("solib-dsbt", class_maintenance,
- &solib_dsbt_debug, _("\
- Set internal debugging of shared library code for DSBT ELF."), _("\
- Show internal debugging of shared library code for DSBT ELF."), _("\
- When non-zero, DSBT solib specific internal debugging is enabled."),
- NULL,
- show_dsbt_debug,
- &setdebuglist, &showdebuglist);
- }
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