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Diffstat (limited to 'gdb/solib-dsbt.c')
| -rw-r--r-- | gdb/solib-dsbt.c | 1259 |
1 files changed, 1259 insertions, 0 deletions
diff --git a/gdb/solib-dsbt.c b/gdb/solib-dsbt.c new file mode 100644 index 0000000..2569395 --- /dev/null +++ b/gdb/solib-dsbt.c @@ -0,0 +1,1259 @@ +/* Handle TIC6X (DSBT) shared libraries for GDB, the GNU Debugger. + Copyright (C) 2010, 2011 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 "gdb_string.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 "exceptions.h" + +#define GOT_MODULE_OFFSET 4 + +/* Flag which indicates whether internal debug messages should be printed. */ +static 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 +{ + /* The loadmap, digested into an easier to use form. */ + struct int_elf32_dsbt_loadmap *map; +}; + +/* 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 *main_executable_lm_info; + + /* 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; + struct int_elf32_dsbt_loadmap *interp_loadmap; + + /* Cached value for lm_base, below. */ + CORE_ADDR lm_base_cache; + + /* Link map address for main module. */ + CORE_ADDR main_lm_addr; + + int enable_break2_done; + + CORE_ADDR interp_text_sect_low; + CORE_ADDR interp_text_sect_high; + CORE_ADDR interp_plt_sect_low; + CORE_ADDR interp_plt_sect_high; +}; + +/* Per-program-space data key. */ +static const struct program_space_data *solib_dsbt_pspace_data; + +static void +dsbt_pspace_data_cleanup (struct program_space *pspace, void *arg) +{ + struct dsbt_info *info; + + info = program_space_data (pspace, solib_dsbt_pspace_data); + xfree (info); +} + +/* 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 = program_space_data (current_program_space, solib_dsbt_pspace_data); + if (info != NULL) + return info; + + info = XZALLOC (struct dsbt_info); + set_program_space_data (current_program_space, solib_dsbt_pspace_data, info); + + info->enable_break2_done = 0; + info->lm_base_cache = 0; + info->main_lm_addr = 0; + + return info; +} + + +static void +dsbt_print_loadmap (struct int_elf32_dsbt_loadmap *map) +{ + int i; + + if (map == NULL) + printf_filtered ("(null)\n"); + else if (map->version != 0) + printf_filtered (_("Unsupported map version: %d\n"), map->version); + else + { + printf_filtered ("version %d\n", map->version); + + for (i = 0; i < map->nsegs; i++) + printf_filtered ("%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 (gdb_byte *buf) +{ + enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); + struct ext_elf32_dsbt_loadmap *ext_ldmbuf; + struct int_elf32_dsbt_loadmap *int_ldmbuf; + + int version, seg, nsegs; + int ext_ldmbuf_size, 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 = 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 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) +{ + gdb_byte *buf; + struct dsbt_info *info = get_dsbt_info (); + + if (0 >= target_read_alloc (¤t_target, TARGET_OBJECT_FDPIC, + "exec", (gdb_byte**) &buf)) + { + info->exec_loadmap = NULL; + error (_("Error reading DSBT exec loadmap")); + } + info->exec_loadmap = decode_loadmap (buf); + if (solib_dsbt_debug) + dsbt_print_loadmap (info->exec_loadmap); + + if (0 >= target_read_alloc (¤t_target, TARGET_OBJECT_FDPIC, + "interp", (gdb_byte**)&buf)) + { + info->interp_loadmap = NULL; + error (_("Error reading DSBT interp loadmap")); + } + info->interp_loadmap = decode_loadmap (buf); + 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 = 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 = 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_break2 (void); + +/* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is + returned and the corresponding PTR is set. */ + +static int +scan_dyntag (int dyntag, bfd *abfd, CORE_ADDR *ptr) +{ + int arch_size, step, sect_size; + long dyn_tag; + CORE_ADDR dyn_ptr, dyn_addr; + gdb_byte *bufend, *bufstart, *buf; + Elf32_External_Dyn *x_dynp_32; + Elf64_External_Dyn *x_dynp_64; + struct bfd_section *sect; + struct target_section *target_section; + + if (abfd == NULL) + return 0; + + if (bfd_get_flavour (abfd) != bfd_target_elf_flavour) + return 0; + + arch_size = bfd_get_arch_size (abfd); + if (arch_size == -1) + return 0; + + /* Find the start address of the .dynamic section. */ + sect = bfd_get_section_by_name (abfd, ".dynamic"); + if (sect == NULL) + return 0; + + for (target_section = current_target_sections->sections; + target_section < current_target_sections->sections_end; + target_section++) + if (sect == target_section->the_bfd_section) + break; + if (target_section < current_target_sections->sections_end) + dyn_addr = target_section->addr; + else + { + /* ABFD may come from OBJFILE acting only as a symbol file without being + loaded into the target (see add_symbol_file_command). This case is + such fallback to the file VMA address without the possibility of + having the section relocated to its actual in-memory address. */ + + dyn_addr = bfd_section_vma (abfd, sect); + } + + /* Read in .dynamic from the BFD. We will get the actual value + from memory later. */ + sect_size = bfd_section_size (abfd, sect); + buf = bufstart = alloca (sect_size); + if (!bfd_get_section_contents (abfd, sect, + buf, 0, sect_size)) + return 0; + + /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ + step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) + : sizeof (Elf64_External_Dyn); + for (bufend = buf + sect_size; + buf < bufend; + buf += step) + { + if (arch_size == 32) + { + x_dynp_32 = (Elf32_External_Dyn *) buf; + dyn_tag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag); + dyn_ptr = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_un.d_ptr); + } + else + { + x_dynp_64 = (Elf64_External_Dyn *) buf; + dyn_tag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag); + dyn_ptr = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_un.d_ptr); + } + if (dyn_tag == DT_NULL) + return 0; + if (dyn_tag == dyntag) + { + /* If requested, try to read the runtime value of this .dynamic + entry. */ + if (ptr) + { + struct type *ptr_type; + gdb_byte ptr_buf[8]; + CORE_ADDR ptr_addr; + + ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; + ptr_addr = dyn_addr + (buf - bufstart) + arch_size / 8; + if (target_read_memory (ptr_addr, ptr_buf, arch_size / 8) == 0) + dyn_ptr = extract_typed_address (ptr_buf, ptr_type); + *ptr = dyn_ptr; + } + return 1; + } + } + + return 0; +} + +/* An expensive way to lookup the value of a single symbol for + bfd's that are only temporary anyway. This is used by the + shared library support to find the address of the debugger + interface structures in the shared library. + + Note that 0 is specifically allowed as an error return (no + such symbol). */ + +static CORE_ADDR +bfd_lookup_symbol (bfd *abfd, char *symname) +{ + long storage_needed; + asymbol *sym; + asymbol **symbol_table; + unsigned int number_of_symbols; + unsigned int i; + struct cleanup *back_to; + CORE_ADDR symaddr = 0; + + storage_needed = bfd_get_symtab_upper_bound (abfd); + + if (storage_needed > 0) + { + symbol_table = (asymbol **) xmalloc (storage_needed); + back_to = make_cleanup (xfree, symbol_table); + number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); + + for (i = 0; i < number_of_symbols; i++) + { + sym = *symbol_table++; + if (strcmp (sym->name, symname) == 0) + { + /* Bfd symbols are section relative. */ + symaddr = sym->value + sym->section->vma; + break; + } + } + do_cleanups (back_to); + } + + if (symaddr) + return symaddr; + + /* Look for the symbol in the dynamic string table too. */ + + storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd); + + if (storage_needed > 0) + { + symbol_table = (asymbol **) xmalloc (storage_needed); + back_to = make_cleanup (xfree, symbol_table); + number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table); + + for (i = 0; i < number_of_symbols; i++) + { + sym = *symbol_table++; + if (strcmp (sym->name, symname) == 0) + { + /* Bfd symbols are section relative. */ + symaddr = sym->value + sym->section->vma; + break; + } + } + do_cleanups (back_to); + } + + return symaddr; +} + + +/* If no open symbol file, attempt to locate and open the main symbol + file. + + If FROM_TTYP dereferences to a non-zero integer, allow messages to + be printed. This parameter is a pointer rather than an int because + open_symbol_file_object is called via catch_errors and + catch_errors requires a pointer argument. */ + +static int +open_symbol_file_object (void *from_ttyp) +{ + /* 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 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, + symfile_objfile); + + if (got_sym != 0) + { + addr = SYMBOL_VALUE_ADDRESS (got_sym); + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "lm_base: get addr %x by _GLOBAL_OFFSET_TABLE_.\n", + (unsigned int) addr); + } + else if (scan_dyntag (DT_PLTGOT, exec_bfd, &addr)) + { + struct int_elf32_dsbt_loadmap *ldm; + + dsbt_get_initial_loadmaps (); + ldm = info->exec_loadmap; + addr += displacement_from_map (ldm, addr); + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "lm_base: get addr %x by DT_PLTGOT.\n", + (unsigned int) addr); + } + else + { + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "lm_base: _GLOBAL_OFFSET_TABLE_ not found.\n"); + return 0; + } + addr += GOT_MODULE_OFFSET; + + if (solib_dsbt_debug) + fprintf_unfiltered (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) + fprintf_unfiltered (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 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) + fprintf_unfiltered (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) + { + int errcode; + char *name_buf; + 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 = xcalloc (1, sizeof (struct so_list)); + sop->lm_info = xcalloc (1, sizeof (struct lm_info)); + sop->lm_info->map = loadmap; + /* Fetch the name. */ + addr = extract_unsigned_integer (lm_buf.l_name, + sizeof (lm_buf.l_name), + byte_order); + target_read_string (addr, &name_buf, SO_NAME_MAX_PATH_SIZE - 1, + &errcode); + + if (errcode != 0) + warning (_("Can't read pathname for link map entry: %s."), + safe_strerror (errcode)); + else + { + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, "current_sos: name = %s\n", + name_buf); + + strncpy (sop->so_name, name_buf, SO_NAME_MAX_PATH_SIZE - 1); + sop->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; + xfree (name_buf); + 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); + } + + enable_break2 (); + + 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, NULL)); +} + +/* 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.")); +} + +/* 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), the symbol + _dl_debug_addr points to the r_debug struct which contains + a field called r_brk. r_brk is the address of the function + descriptor upon which a breakpoint must be placed. Being a + function descriptor, we must extract the entry point in order + to set the breakpoint. + + Our strategy will be to get the .interp section from the + executable. This section will provide us with the name of the + interpreter. We'll open the interpreter and then look up + the address of _dl_debug_addr. We then relocate this address + using the interpreter's loadmap. Once the relocated address + is known, we fetch the value (address) corresponding to r_brk + and then use that value to fetch the entry point of the function + we're interested in. */ + +static int +enable_break2 (void) +{ + enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); + int success = 0; + char **bkpt_namep; + asection *interp_sect; + struct dsbt_info *info = get_dsbt_info (); + + if (exec_bfd == NULL) + return 0; + + if (!target_has_execution) + return 0; + + if (info->enable_break2_done) + return 1; + + 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 (exec_bfd, ".interp"); + if (interp_sect) + { + unsigned int interp_sect_size; + gdb_byte *buf; + bfd *tmp_bfd = NULL; + int status; + CORE_ADDR addr, interp_loadmap_addr; + gdb_byte addr_buf[TIC6X_PTR_SIZE]; + struct int_elf32_dsbt_loadmap *ldm; + volatile struct gdb_exception ex; + + /* 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 (exec_bfd, interp_sect); + buf = alloca (interp_sect_size); + bfd_get_section_contents (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. */ + + TRY_CATCH (ex, RETURN_MASK_ALL) + { + tmp_bfd = solib_bfd_open (buf); + } + 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, ".text"); + if (interp_sect) + { + info->interp_text_sect_low + = bfd_section_vma (tmp_bfd, 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 (tmp_bfd, interp_sect); + } + interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); + if (interp_sect) + { + info->interp_plt_sect_low = + bfd_section_vma (tmp_bfd, 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 (tmp_bfd, interp_sect); + } + + addr = bfd_lookup_symbol (tmp_bfd, "_dl_debug_addr"); + if (addr == 0) + { + warning (_("Could not find symbol _dl_debug_addr in dynamic linker")); + enable_break_failure_warning (); + bfd_close (tmp_bfd); + return 0; + } + + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "enable_break: _dl_debug_addr (prior to relocation) = %s\n", + hex_string_custom (addr, 8)); + + addr += displacement_from_map (ldm, addr); + + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "enable_break: _dl_debug_addr (after relocation) = %s\n", + hex_string_custom (addr, 8)); + + /* Fetch the address of the r_debug struct. */ + if (target_read_memory (addr, addr_buf, sizeof addr_buf) != 0) + { + warning (_("Unable to fetch contents of _dl_debug_addr " + "(at address %s) from dynamic linker"), + hex_string_custom (addr, 8)); + } + addr = extract_unsigned_integer (addr_buf, sizeof addr_buf, byte_order); + + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "enable_break: _dl_debug_addr[0..3] = %s\n", + hex_string_custom (addr, 8)); + + /* If it's zero, then the ldso hasn't initialized yet, and so + there are no shared libs yet loaded. */ + if (addr == 0) + { + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "enable_break: ldso not yet initialized\n"); + /* Do not warn, but mark to run again. */ + return 0; + } + + /* Fetch the r_brk field. It's 8 bytes from the start of + _dl_debug_addr. */ + if (target_read_memory (addr + 8, addr_buf, sizeof addr_buf) != 0) + { + warning (_("Unable to fetch _dl_debug_addr->r_brk " + "(at address %s) from dynamic linker"), + hex_string_custom (addr + 8, 8)); + enable_break_failure_warning (); + bfd_close (tmp_bfd); + return 0; + } + addr = extract_unsigned_integer (addr_buf, sizeof addr_buf, byte_order); + + /* We're done with the temporary bfd. */ + bfd_close (tmp_bfd); + + /* We're also done with the loadmap. */ + xfree (ldm); + + /* Remove all the solib event breakpoints. Their addresses + may have changed since the last time we ran the program. */ + remove_solib_event_breakpoints (); + + /* Now (finally!) create the solib breakpoint. */ + create_solib_event_breakpoint (target_gdbarch, addr); + + info->enable_break2_done = 1; + + return 1; + } + + /* Tell the user we couldn't set a dynamic linker breakpoint. */ + enable_break_failure_warning (); + + /* Failure return. */ + return 0; +} + +static int +enable_break (void) +{ + asection *interp_sect; + struct minimal_symbol *start; + + /* Check for the presence of a .interp section. If there is no + such section, the executable is statically linked. */ + + interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); + + if (interp_sect == NULL) + { + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "enable_break: No .interp section found.\n"); + return 0; + } + + start = lookup_minimal_symbol ("_start", NULL, symfile_objfile); + if (start == NULL) + { + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "enable_break: symbol _start is not found.\n"); + return 0; + } + + create_solib_event_breakpoint (target_gdbarch, + SYMBOL_VALUE_ADDRESS (start)); + + if (solib_dsbt_debug) + fprintf_unfiltered (gdb_stdlog, + "enable_break: solib event breakpoint placed at : %s\n", + hex_string_custom (SYMBOL_VALUE_ADDRESS (start), 8)); + return 1; +} + +/* 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. */ + +static void +dsbt_special_symbol_handling (void) +{ +} + +static void +dsbt_relocate_main_executable (void) +{ + int status; + CORE_ADDR exec_addr, interp_addr; + struct int_elf32_dsbt_loadmap *ldm; + struct cleanup *old_chain; + struct section_offsets *new_offsets; + int changed; + struct obj_section *osect; + struct dsbt_info *info = get_dsbt_info (); + + dsbt_get_initial_loadmaps (); + ldm = info->exec_loadmap; + + xfree (info->main_executable_lm_info); + info->main_executable_lm_info = xcalloc (1, sizeof (struct lm_info)); + info->main_executable_lm_info->map = ldm; + + new_offsets = xcalloc (symfile_objfile->num_sections, + sizeof (struct section_offsets)); + old_chain = make_cleanup (xfree, new_offsets); + changed = 0; + + ALL_OBJFILE_OSECTIONS (symfile_objfile, osect) + { + CORE_ADDR orig_addr, addr, offset; + int osect_idx; + int seg; + + osect_idx = osect->the_bfd_section->index; + + /* Current address of section. */ + addr = obj_section_addr (osect); + /* Offset from where this section started. */ + offset = ANOFFSET (symfile_objfile->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->offsets[osect_idx] + = ldm->segs[seg].addr - ldm->segs[seg].p_vaddr; + + if (new_offsets->offsets[osect_idx] != offset) + changed = 1; + break; + } + } + } + + if (changed) + objfile_relocate (symfile_objfile, new_offsets); + + do_cleanups (old_chain); + + /* Now that symfile_objfile 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 expansion of the macro + 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->enable_break2_done = 0; + info->main_lm_addr = 0; + if (info->main_executable_lm_info != 0) + { + xfree (info->main_executable_lm_info->map); + xfree (info->main_executable_lm_info); + info->main_executable_lm_info = 0; + } +} + +static void +dsbt_free_so (struct so_list *so) +{ + xfree (so->lm_info->map); + xfree (so->lm_info); +} + +static void +dsbt_relocate_section_addresses (struct so_list *so, + struct target_section *sec) +{ + int seg; + struct int_elf32_dsbt_loadmap *map; + + map = so->lm_info->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) +{ + fprintf_filtered (file, _("solib-dsbt debugging is %s.\n"), value); +} + +struct target_so_ops dsbt_so_ops; + +/* Provide a prototype to silence -Wmissing-prototypes. */ +extern initialize_file_ftype _initialize_dsbt_solib; + +void +_initialize_dsbt_solib (void) +{ + solib_dsbt_pspace_data + = register_program_space_data_with_cleanup (dsbt_pspace_data_cleanup); + + 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.special_symbol_handling = dsbt_special_symbol_handling; + 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_zinteger_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); +} |