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authorKevin Buettner <kevinb@redhat.com>2000-10-24 20:05:36 +0000
committerKevin Buettner <kevinb@redhat.com>2000-10-24 20:05:36 +0000
commit13437d4b4b35feeefd79067153fb01ef80db0fb2 (patch)
treede7c6b47aa66c0a2f7c3fb434ee922ec78180bd8 /gdb/solib-svr4.c
parent42f5c13f56a779a189fb00330b71fc401ad58858 (diff)
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Reorganize solib.c.
Diffstat (limited to 'gdb/solib-svr4.c')
-rw-r--r--gdb/solib-svr4.c1586
1 files changed, 1586 insertions, 0 deletions
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
new file mode 100644
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--- /dev/null
+++ b/gdb/solib-svr4.c
@@ -0,0 +1,1586 @@
+/* Handle SunOS and SVR4 shared libraries for GDB, the GNU Debugger.
+ Copyright 1990, 91, 92, 93, 94, 95, 96, 98, 1999, 2000
+ 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., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#define _SYSCALL32 /* for Sparc64 cross Sparc32 */
+#include "defs.h"
+
+
+#include <sys/types.h>
+#include <signal.h>
+#include "gdb_string.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 "elf/external.h"
+#endif
+
+#ifdef HAVE_LINK_H
+#include <link.h>
+#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 "gdb_regex.h"
+#include "inferior.h"
+#include "environ.h"
+#include "language.h"
+#include "gdbcmd.h"
+
+#include "solist.h"
+#include "solib-svr4.h"
+
+/* Link map info to include in an allocated so_list entry */
+
+struct lm_info
+ {
+ /* Pointer to copy of link map from inferior. The type is char *
+ rather than void *, so that we may use byte offsets to find the
+ various fields without the need for a cast. */
+ char *lm;
+ };
+
+/* On SVR4 systems, a list of symbols in the dynamic linker where
+ GDB can try to place a breakpoint to monitor shared library
+ events.
+
+ If none of these symbols are found, or other errors occur, then
+ SVR4 systems will fall back to using a symbol as the "startup
+ mapping complete" breakpoint address. */
+
+#ifdef SVR4_SHARED_LIBS
+static char *solib_break_names[] =
+{
+ "r_debug_state",
+ "_r_debug_state",
+ "_dl_debug_state",
+ "rtld_db_dlactivity",
+ NULL
+};
+#endif
+
+#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",
+ "_DYNAMIC__MGC",
+ NULL
+};
+#endif
+
+static char *main_name_list[] =
+{
+ "main_$main",
+ NULL
+};
+
+
+/* Fetch (and possibly build) an appropriate link_map_offsets structure
+ for native targets using struct definitions from link.h. */
+
+struct link_map_offsets *
+default_svr4_fetch_link_map_offsets (void)
+{
+#ifdef HAVE_LINK_H
+ static struct link_map_offsets lmo;
+ static struct link_map_offsets *lmp = 0;
+#if defined (HAVE_STRUCT_LINK_MAP32)
+ static struct link_map_offsets lmo32;
+ static struct link_map_offsets *lmp32 = 0;
+#endif
+
+#ifndef offsetof
+#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
+#endif
+#define fieldsize(TYPE, MEMBER) (sizeof (((TYPE *)0)->MEMBER))
+
+ if (lmp == 0)
+ {
+ lmp = &lmo;
+
+#ifdef SVR4_SHARED_LIBS
+ lmo.r_debug_size = sizeof (struct r_debug);
+
+ lmo.r_map_offset = offsetof (struct r_debug, r_map);
+ lmo.r_map_size = fieldsize (struct r_debug, r_map);
+
+ lmo.link_map_size = sizeof (struct link_map);
+
+ lmo.l_addr_offset = offsetof (struct link_map, l_addr);
+ lmo.l_addr_size = fieldsize (struct link_map, l_addr);
+
+ lmo.l_next_offset = offsetof (struct link_map, l_next);
+ lmo.l_next_size = fieldsize (struct link_map, l_next);
+
+ lmo.l_prev_offset = offsetof (struct link_map, l_prev);
+ lmo.l_prev_size = fieldsize (struct link_map, l_prev);
+
+ lmo.l_name_offset = offsetof (struct link_map, l_name);
+ lmo.l_name_size = fieldsize (struct link_map, l_name);
+#else /* !SVR4_SHARED_LIBS */
+ lmo.link_map_size = sizeof (struct link_map);
+
+ lmo.l_addr_offset = offsetof (struct link_map, lm_addr);
+ lmo.l_addr_size = fieldsize (struct link_map, lm_addr);
+
+ lmo.l_next_offset = offsetof (struct link_map, lm_next);
+ lmo.l_next_size = fieldsize (struct link_map, lm_next);
+
+ lmo.l_name_offset = offsetof (struct link_map, lm_name);
+ lmo.l_name_size = fieldsize (struct link_map, lm_name);
+#endif /* SVR4_SHARED_LIBS */
+ }
+
+#if defined (HAVE_STRUCT_LINK_MAP32)
+ if (lmp32 == 0)
+ {
+ lmp32 = &lmo32;
+
+ lmo32.r_debug_size = sizeof (struct r_debug32);
+
+ lmo32.r_map_offset = offsetof (struct r_debug32, r_map);
+ lmo32.r_map_size = fieldsize (struct r_debug32, r_map);
+
+ lmo32.link_map_size = sizeof (struct link_map32);
+
+ lmo32.l_addr_offset = offsetof (struct link_map32, l_addr);
+ lmo32.l_addr_size = fieldsize (struct link_map32, l_addr);
+
+ lmo32.l_next_offset = offsetof (struct link_map32, l_next);
+ lmo32.l_next_size = fieldsize (struct link_map32, l_next);
+
+ lmo32.l_prev_offset = offsetof (struct link_map32, l_prev);
+ lmo32.l_prev_size = fieldsize (struct link_map32, l_prev);
+
+ lmo32.l_name_offset = offsetof (struct link_map32, l_name);
+ lmo32.l_name_size = fieldsize (struct link_map32, l_name);
+ }
+#endif /* defined (HAVE_STRUCT_LINK_MAP32) */
+
+#if defined (HAVE_STRUCT_LINK_MAP32)
+ if (bfd_get_arch_size (exec_bfd) == 32)
+ return lmp32;
+ else
+#endif
+ return lmp;
+
+#else
+
+ internal_error ("default_svr4_fetch_link_map_offsets called without HAVE_LINK_H defined.");
+ return 0;
+
+#endif /* HAVE_LINK_H */
+}
+
+/* Macro to extract an address from a solib structure.
+ When GDB is configured for some 32-bit targets (e.g. Solaris 2.7
+ sparc), BFD is configured to handle 64-bit targets, so CORE_ADDR is
+ 64 bits. We have to extract only the significant bits of addresses
+ to get the right address when accessing the core file BFD. */
+
+#define SOLIB_EXTRACT_ADDRESS(MEMBER) \
+ extract_address (&(MEMBER), sizeof (MEMBER))
+
+/* local data declarations */
+
+#ifndef SVR4_SHARED_LIBS
+
+/* NOTE: converted the macros LM_ADDR, LM_NEXT, LM_NAME and
+ IGNORE_FIRST_LINK_MAP_ENTRY into functions (see below).
+ MVS, June 2000 */
+
+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;
+
+#endif /* !SVR4_SHARED_LIBS */
+
+/* link map access functions */
+
+static CORE_ADDR
+LM_ADDR (struct so_list *so)
+{
+ struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
+
+ return extract_address (so->lm_info->lm + lmo->l_addr_offset, lmo->l_addr_size);
+}
+
+static CORE_ADDR
+LM_NEXT (struct so_list *so)
+{
+ struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
+
+ return extract_address (so->lm_info->lm + lmo->l_next_offset, lmo->l_next_size);
+}
+
+static CORE_ADDR
+LM_NAME (struct so_list *so)
+{
+ struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
+
+ return extract_address (so->lm_info->lm + lmo->l_name_offset, lmo->l_name_size);
+}
+
+#ifndef SVR4_SHARED_LIBS
+
+static int
+IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so)
+{
+ return 0;
+}
+
+#else /* SVR4_SHARED_LIBS */
+
+static int
+IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so)
+{
+ struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
+
+ return extract_address (so->lm_info->lm + lmo->l_prev_offset,
+ lmo->l_prev_size) == 0;
+}
+
+#endif /* !SVR4_SHARED_LIBS */
+
+
+static CORE_ADDR debug_base; /* Base of dynamic linker structures */
+static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */
+
+/* Local function prototypes */
+
+static int match_main (char *);
+
+/* If non-zero, this is a prefix that will be added to the front of the name
+ shared libraries with an absolute filename for loading. */
+static char *solib_absolute_prefix = NULL;
+
+/* If non-empty, this is a search path for loading non-absolute shared library
+ symbol files. This takes precedence over the environment variables PATH
+ and LD_LIBRARY_PATH. */
+static char *solib_search_path = NULL;
+
+
+#ifndef SVR4_SHARED_LIBS
+
+/* Allocate the runtime common object file. */
+
+static void
+allocate_rt_common_objfile (void)
+{
+ struct objfile *objfile;
+ struct objfile *last_one;
+
+ objfile = (struct objfile *) xmalloc (sizeof (struct objfile));
+ memset (objfile, 0, sizeof (struct objfile));
+ objfile->md = NULL;
+ obstack_specify_allocation (&objfile->psymbol_cache.cache, 0, 0,
+ xmalloc, free);
+ obstack_specify_allocation (&objfile->psymbol_obstack, 0, 0, xmalloc,
+ free);
+ obstack_specify_allocation (&objfile->symbol_obstack, 0, 0, xmalloc,
+ free);
+ obstack_specify_allocation (&objfile->type_obstack, 0, 0, xmalloc,
+ free);
+ objfile->name = mstrsave (objfile->md, "rt_common");
+
+ /* Add this file onto the tail of the linked list of other such files. */
+
+ objfile->next = NULL;
+ if (object_files == NULL)
+ object_files = objfile;
+ else
+ {
+ for (last_one = object_files;
+ last_one->next;
+ last_one = last_one->next);
+ last_one->next = objfile;
+ }
+
+ rt_common_objfile = objfile;
+}
+
+/* Read all dynamically loaded common symbol definitions from the inferior
+ and put them into the minimal symbol table for the runtime common
+ objfile. */
+
+static void
+solib_add_common_symbols (CORE_ADDR rtc_symp)
+{
+ struct rtc_symb inferior_rtc_symb;
+ struct nlist inferior_rtc_nlist;
+ int len;
+ char *name;
+
+ /* Remove any runtime common symbols from previous runs. */
+
+ if (rt_common_objfile != NULL && rt_common_objfile->minimal_symbol_count)
+ {
+ obstack_free (&rt_common_objfile->symbol_obstack, 0);
+ obstack_specify_allocation (&rt_common_objfile->symbol_obstack, 0, 0,
+ xmalloc, free);
+ rt_common_objfile->minimal_symbol_count = 0;
+ rt_common_objfile->msymbols = NULL;
+ }
+
+ init_minimal_symbol_collection ();
+ make_cleanup_discard_minimal_symbols ();
+
+ while (rtc_symp)
+ {
+ read_memory (rtc_symp,
+ (char *) &inferior_rtc_symb,
+ sizeof (inferior_rtc_symb));
+ read_memory (SOLIB_EXTRACT_ADDRESS (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;
+
+ name = xmalloc (len);
+ read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_nlist.n_un.n_name),
+ name, len);
+
+ /* Allocate the runtime common objfile if necessary. */
+ if (rt_common_objfile == NULL)
+ allocate_rt_common_objfile ();
+
+ prim_record_minimal_symbol (name, inferior_rtc_nlist.n_value,
+ mst_bss, rt_common_objfile);
+ free (name);
+ }
+ rtc_symp = SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_next);
+ }
+
+ /* Install any minimal symbols that have been collected as the current
+ minimal symbols for the runtime common objfile. */
+
+ install_minimal_symbols (rt_common_objfile);
+}
+
+#endif /* SVR4_SHARED_LIBS */
+
+
+#ifdef SVR4_SHARED_LIBS
+
+static CORE_ADDR bfd_lookup_symbol (bfd *, char *);
+
+/*
+
+ LOCAL FUNCTION
+
+ bfd_lookup_symbol -- lookup the value for a specific symbol
+
+ SYNOPSIS
+
+ CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)
+
+ DESCRIPTION
+
+ 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)
+{
+ unsigned int 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 (free, (PTR) symbol_table);
+ number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
+
+ for (i = 0; i < number_of_symbols; i++)
+ {
+ sym = *symbol_table++;
+ if (STREQ (sym->name, symname))
+ {
+ /* Bfd symbols are section relative. */
+ symaddr = sym->value + sym->section->vma;
+ break;
+ }
+ }
+ do_cleanups (back_to);
+ }
+
+ if (symaddr)
+ return symaddr;
+
+ /* On FreeBSD, the dynamic linker is stripped by default. So we'll
+ have to check 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 (free, (PTR) symbol_table);
+ number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table);
+
+ for (i = 0; i < number_of_symbols; i++)
+ {
+ sym = *symbol_table++;
+ if (STREQ (sym->name, symname))
+ {
+ /* Bfd symbols are section relative. */
+ symaddr = sym->value + sym->section->vma;
+ break;
+ }
+ }
+ do_cleanups (back_to);
+ }
+
+ return symaddr;
+}
+
+#ifdef HANDLE_SVR4_EXEC_EMULATORS
+
+/*
+ Solaris BCP (the part of Solaris which allows it to run SunOS4
+ a.out files) throws in another wrinkle. Solaris does not fill
+ in the usual a.out link map structures when running BCP programs,
+ the only way to get at them is via groping around in the dynamic
+ linker.
+ The dynamic linker and it's structures are located in the shared
+ C library, which gets run as the executable's "interpreter" by
+ the kernel.
+
+ Note that we can assume nothing about the process state at the time
+ we need to find these structures. We may be stopped on the first
+ instruction of the interpreter (C shared library), the first
+ instruction of the executable itself, or somewhere else entirely
+ (if we attached to the process for example).
+ */
+
+static char *debug_base_symbols[] =
+{
+ "r_debug", /* Solaris 2.3 */
+ "_r_debug", /* Solaris 2.1, 2.2 */
+ NULL
+};
+
+static int look_for_base (int, CORE_ADDR);
+
+/*
+
+ LOCAL FUNCTION
+
+ look_for_base -- examine file for each mapped address segment
+
+ SYNOPSYS
+
+ static int look_for_base (int fd, CORE_ADDR baseaddr)
+
+ DESCRIPTION
+
+ This function is passed to proc_iterate_over_mappings, which
+ causes it to get called once for each mapped address space, with
+ an open file descriptor for the file mapped to that space, and the
+ base address of that mapped space.
+
+ Our job is to find the debug base symbol in the file that this
+ fd is open on, if it exists, and if so, initialize the dynamic
+ linker structure base address debug_base.
+
+ Note that this is a computationally expensive proposition, since
+ we basically have to open a bfd on every call, so we specifically
+ avoid opening the exec file.
+ */
+
+static int
+look_for_base (int fd, CORE_ADDR baseaddr)
+{
+ bfd *interp_bfd;
+ CORE_ADDR address = 0;
+ char **symbolp;
+
+ /* If the fd is -1, then there is no file that corresponds to this
+ mapped memory segment, so skip it. Also, if the fd corresponds
+ to the exec file, skip it as well. */
+
+ if (fd == -1
+ || (exec_bfd != NULL
+ && fdmatch (fileno ((FILE *) (exec_bfd->iostream)), fd)))
+ {
+ return (0);
+ }
+
+ /* Try to open whatever random file this fd corresponds to. Note that
+ we have no way currently to find the filename. Don't gripe about
+ any problems we might have, just fail. */
+
+ if ((interp_bfd = bfd_fdopenr ("unnamed", gnutarget, fd)) == NULL)
+ {
+ return (0);
+ }
+ if (!bfd_check_format (interp_bfd, bfd_object))
+ {
+ /* FIXME-leak: on failure, might not free all memory associated with
+ interp_bfd. */
+ bfd_close (interp_bfd);
+ return (0);
+ }
+
+ /* Now try to find our debug base symbol in this file, which we at
+ least know to be a valid ELF executable or shared library. */
+
+ for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++)
+ {
+ address = bfd_lookup_symbol (interp_bfd, *symbolp);
+ if (address != 0)
+ {
+ break;
+ }
+ }
+ if (address == 0)
+ {
+ /* FIXME-leak: on failure, might not free all memory associated with
+ interp_bfd. */
+ bfd_close (interp_bfd);
+ return (0);
+ }
+
+ /* Eureka! We found the symbol. But now we may need to relocate it
+ by the base address. If the symbol's value is less than the base
+ address of the shared library, then it hasn't yet been relocated
+ by the dynamic linker, and we have to do it ourself. FIXME: Note
+ that we make the assumption that the first segment that corresponds
+ to the shared library has the base address to which the library
+ was relocated. */
+
+ if (address < baseaddr)
+ {
+ address += baseaddr;
+ }
+ debug_base = address;
+ /* FIXME-leak: on failure, might not free all memory associated with
+ interp_bfd. */
+ bfd_close (interp_bfd);
+ return (1);
+}
+#endif /* HANDLE_SVR4_EXEC_EMULATORS */
+
+/*
+
+ 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 (void)
+{
+ sec_ptr dyninfo_sect;
+ int dyninfo_sect_size;
+ CORE_ADDR dyninfo_addr;
+ char *buf;
+ char *bufend;
+ int arch_size;
+
+ /* Find the start address of the .dynamic section. */
+ dyninfo_sect = bfd_get_section_by_name (exec_bfd, ".dynamic");
+ if (dyninfo_sect == NULL)
+ return 0;
+ dyninfo_addr = bfd_section_vma (exec_bfd, dyninfo_sect);
+
+ /* Read in .dynamic section, silently ignore errors. */
+ dyninfo_sect_size = bfd_section_size (exec_bfd, dyninfo_sect);
+ 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. */
+
+ arch_size = bfd_get_arch_size (exec_bfd);
+ if (arch_size == -1) /* failure */
+ return 0;
+
+ if (arch_size == 32)
+ { /* 32-bit elf */
+ 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;
+ }
+#ifdef DT_MIPS_RLD_MAP
+ else if (dyn_tag == DT_MIPS_RLD_MAP)
+ {
+ char *pbuf;
+
+ pbuf = alloca (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));
+ }
+#endif
+ }
+ }
+ else /* 64-bit elf */
+ {
+ for (bufend = buf + dyninfo_sect_size;
+ buf < bufend;
+ buf += sizeof (Elf64_External_Dyn))
+ {
+ Elf64_External_Dyn *x_dynp = (Elf64_External_Dyn *) buf;
+ long dyn_tag;
+ CORE_ADDR dyn_ptr;
+
+ dyn_tag = bfd_h_get_64 (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_64 (exec_bfd,
+ (bfd_byte *) x_dynp->d_un.d_ptr);
+ return dyn_ptr;
+ }
+ }
+ }
+
+ /* 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 (void)
+{
+
+#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, NULL, 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 for ELF executables. */
+
+ if (debug_base == 0)
+ {
+ if (exec_bfd != NULL
+ && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
+ debug_base = elf_locate_base ();
+#ifdef HANDLE_SVR4_EXEC_EMULATORS
+ /* Try it the hard way for emulated executables. */
+ else if (inferior_pid != 0 && target_has_execution)
+ proc_iterate_over_mappings (look_for_base);
+#endif
+ }
+ return (debug_base);
+
+#endif /* !SVR4_SHARED_LIBS */
+
+}
+
+/*
+
+ LOCAL FUNCTION
+
+ first_link_map_member -- locate first member in dynamic linker's map
+
+ SYNOPSIS
+
+ static CORE_ADDR first_link_map_member (void)
+
+ DESCRIPTION
+
+ Find the first element in the inferior's dynamic link map, and
+ return its address in the inferior. This function doesn't copy the
+ link map entry itself into our address space; current_sos actually
+ does the reading. */
+
+static CORE_ADDR
+first_link_map_member (void)
+{
+ CORE_ADDR lm = 0;
+
+#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 (SOLIB_EXTRACT_ADDRESS (dynamic_copy.ld_un.ld_2),
+ (char *) &ld_2_copy, sizeof (struct link_dynamic_2));
+ lm = SOLIB_EXTRACT_ADDRESS (ld_2_copy.ld_loaded);
+ }
+
+#else /* SVR4_SHARED_LIBS */
+ struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
+ char *r_map_buf = xmalloc (lmo->r_map_size);
+ struct cleanup *cleanups = make_cleanup (free, r_map_buf);
+
+ read_memory (debug_base + lmo->r_map_offset, r_map_buf, lmo->r_map_size);
+
+ lm = extract_address (r_map_buf, lmo->r_map_size);
+
+ /* FIXME: Perhaps we should validate the info somehow, perhaps by
+ checking r_version for a known version number, or r_state for
+ RT_CONSISTENT. */
+
+ do_cleanups (cleanups);
+
+#endif /* !SVR4_SHARED_LIBS */
+
+ return (lm);
+}
+
+#ifdef SVR4_SHARED_LIBS
+/*
+
+ LOCAL FUNCTION
+
+ open_symbol_file_object
+
+ SYNOPSIS
+
+ void open_symbol_file_object (void *from_tty)
+
+ DESCRIPTION
+
+ If no open symbol file, attempt to locate and open the main symbol
+ file. On SVR4 systems, this is the first link map entry. If its
+ name is here, we can open it. Useful when attaching to a process
+ without first loading its 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)
+{
+ CORE_ADDR lm, l_name;
+ char *filename;
+ int errcode;
+ int from_tty = *(int *)from_ttyp;
+ struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
+ char *l_name_buf = xmalloc (lmo->l_name_size);
+ struct cleanup *cleanups = make_cleanup (free, l_name_buf);
+
+ if (symfile_objfile)
+ if (!query ("Attempt to reload symbols from process? "))
+ return 0;
+
+ if ((debug_base = locate_base ()) == 0)
+ return 0; /* failed somehow... */
+
+ /* First link map member should be the executable. */
+ if ((lm = first_link_map_member ()) == 0)
+ return 0; /* failed somehow... */
+
+ /* Read address of name from target memory to GDB. */
+ read_memory (lm + lmo->l_name_offset, l_name_buf, lmo->l_name_size);
+
+ /* Convert the address to host format. */
+ l_name = extract_address (l_name_buf, lmo->l_name_size);
+
+ /* Free l_name_buf. */
+ do_cleanups (cleanups);
+
+ if (l_name == 0)
+ return 0; /* No filename. */
+
+ /* Now fetch the filename from target memory. */
+ target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode);
+
+ if (errcode)
+ {
+ warning ("failed to read exec filename from attached file: %s",
+ safe_strerror (errcode));
+ return 0;
+ }
+
+ make_cleanup (free, filename);
+ /* Have a pathname: read the symbol file. */
+ symbol_file_command (filename, from_tty);
+
+ return 1;
+}
+#else
+
+static int
+open_symbol_file_object (int *from_ttyp)
+{
+ return 1;
+}
+
+#endif /* SVR4_SHARED_LIBS */
+
+
+/* LOCAL FUNCTION
+
+ current_sos -- build a list of currently loaded shared objects
+
+ SYNOPSIS
+
+ struct so_list *current_sos ()
+
+ DESCRIPTION
+
+ 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 *
+svr4_current_sos (void)
+{
+ CORE_ADDR lm;
+ struct so_list *head = 0;
+ struct so_list **link_ptr = &head;
+
+ /* Make sure we've looked up the inferior's dynamic linker's base
+ structure. */
+ if (! debug_base)
+ {
+ debug_base = locate_base ();
+
+ /* If we can't find the dynamic linker's base structure, this
+ must not be a dynamically linked executable. Hmm. */
+ if (! debug_base)
+ return 0;
+ }
+
+ /* Walk the inferior's link map list, and build our list of
+ `struct so_list' nodes. */
+ lm = first_link_map_member ();
+ while (lm)
+ {
+ struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
+ struct so_list *new
+ = (struct so_list *) xmalloc (sizeof (struct so_list));
+ struct cleanup *old_chain = make_cleanup (free, new);
+
+ memset (new, 0, sizeof (*new));
+
+ new->lm_info = xmalloc (sizeof (struct lm_info));
+ make_cleanup (free, new->lm_info);
+
+ new->lm_info->lm = xmalloc (lmo->link_map_size);
+ make_cleanup (free, new->lm_info->lm);
+ memset (new->lm_info->lm, 0, lmo->link_map_size);
+
+ read_memory (lm, new->lm_info->lm, lmo->link_map_size);
+
+ lm = LM_NEXT (new);
+
+ /* 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))
+ free_so (new);
+ else
+ {
+ int errcode;
+ char *buffer;
+
+ /* Extract this shared object's name. */
+ target_read_string (LM_NAME (new), &buffer,
+ SO_NAME_MAX_PATH_SIZE - 1, &errcode);
+ if (errcode != 0)
+ {
+ warning ("current_sos: Can't read pathname for load map: %s\n",
+ safe_strerror (errcode));
+ }
+ else
+ {
+ strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1);
+ new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
+ free (buffer);
+ strcpy (new->so_original_name, new->so_name);
+ }
+
+ /* If this entry has no name, or its name matches the name
+ for the main executable, don't include it in the list. */
+ if (! new->so_name[0]
+ || match_main (new->so_name))
+ free_so (new);
+ else
+ {
+ new->next = 0;
+ *link_ptr = new;
+ link_ptr = &new->next;
+ }
+ }
+
+ discard_cleanups (old_chain);
+ }
+
+ return head;
+}
+
+
+/* On some systems, the only way to recognize the link map entry for
+ the main executable file is by looking at its name. Return
+ non-zero iff SONAME matches one of the known main executable names. */
+
+static int
+match_main (char *soname)
+{
+ char **mainp;
+
+ for (mainp = main_name_list; *mainp != NULL; mainp++)
+ {
+ if (strcmp (soname, *mainp) == 0)
+ return (1);
+ }
+
+ return (0);
+}
+
+
+#ifdef SVR4_SHARED_LIBS
+
+/* Return 1 if PC lies in the dynamic symbol resolution code of the
+ SVR4 run time loader. */
+
+static CORE_ADDR interp_text_sect_low;
+static CORE_ADDR interp_text_sect_high;
+static CORE_ADDR interp_plt_sect_low;
+static CORE_ADDR interp_plt_sect_high;
+
+int
+in_svr4_dynsym_resolve_code (CORE_ADDR pc)
+{
+ return ((pc >= interp_text_sect_low && pc < interp_text_sect_high)
+ || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high)
+ || in_plt_section (pc, NULL));
+}
+#endif
+
+/*
+
+ 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.
+
+ */
+
+#ifndef SVR4_SHARED_LIBS
+
+static int
+disable_break (void)
+{
+ int status = 1;
+
+ 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 = SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_bp_addr);
+ write_memory (breakpoint_addr, (char *) &debug_copy.ldd_bp_inst,
+ sizeof (debug_copy.ldd_bp_inst));
+
+ /* 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);
+}
+
+#endif /* #ifdef SVR4_SHARED_LIBS */
+
+/*
+
+ 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 (void)
+{
+ 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 = SOLIB_EXTRACT_ADDRESS (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;
+ asection *interp_sect;
+
+ /* First, remove all the solib event breakpoints. Their addresses
+ may have changed since the last time we ran the program. */
+ remove_solib_event_breakpoints ();
+
+#ifdef SVR4_SHARED_LIBS
+ interp_text_sect_low = interp_text_sect_high = 0;
+ interp_plt_sect_low = 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;
+ char *buf;
+ CORE_ADDR load_addr;
+ bfd *tmp_bfd;
+ CORE_ADDR sym_addr = 0;
+
+ /* 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.
+
+ This address is stored on the stack. However, I've been unable
+ to find any magic formula to find it for Solaris (appears to
+ be trivial on GNU/Linux). Therefore, we have to try an alternate
+ mechanism to find the dynamic linker's base address. */
+ tmp_bfd = bfd_openr (buf, gnutarget);
+ if (tmp_bfd == NULL)
+ goto bkpt_at_symbol;
+
+ /* Make sure the dynamic linker's really a useful object. */
+ if (!bfd_check_format (tmp_bfd, bfd_object))
+ {
+ warning ("Unable to grok dynamic linker %s as an object file", buf);
+ bfd_close (tmp_bfd);
+ goto bkpt_at_symbol;
+ }
+
+ /* We find the dynamic linker's base address by examining the
+ current pc (which point at the entry point for the dynamic
+ linker) and subtracting the offset of the entry point. */
+ load_addr = read_pc () - tmp_bfd->start_address;
+
+ /* Record the relocated start and end address of the dynamic linker
+ text and plt section for in_svr4_dynsym_resolve_code. */
+ interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
+ if (interp_sect)
+ {
+ interp_text_sect_low =
+ bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
+ interp_text_sect_high =
+ interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+ }
+ interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
+ if (interp_sect)
+ {
+ interp_plt_sect_low =
+ bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
+ interp_plt_sect_high =
+ interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+ }
+
+ /* Now try to set a breakpoint in the dynamic linker. */
+ for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
+ {
+ sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep);
+ if (sym_addr != 0)
+ break;
+ }
+
+ /* We're done with the temporary bfd. */
+ bfd_close (tmp_bfd);
+
+ if (sym_addr != 0)
+ {
+ create_solib_event_breakpoint (load_addr + sym_addr);
+ return 1;
+ }
+
+ /* For whatever reason we couldn't set a breakpoint in the dynamic
+ linker. Warn and drop into the old code. */
+ bkpt_at_symbol:
+ warning ("Unable to find dynamic linker breakpoint function.\nGDB will be unable to debug shared library initializers\nand track explicitly loaded dynamic code.");
+ }
+#endif
+
+ /* 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, NULL, symfile_objfile);
+ if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
+ {
+ create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol));
+ return 1;
+ }
+ }
+
+ /* Nothing good happened. */
+ success = 0;
+
+#endif /* BKPT_AT_SYMBOL */
+
+#endif /* !SVR4_SHARED_LIBS */
+
+ return (success);
+}
+
+/*
+
+ LOCAL FUNCTION
+
+ special_symbol_handling -- additional shared library symbol handling
+
+ SYNOPSIS
+
+ void special_symbol_handling ()
+
+ 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 SunOS4, 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 runtime common
+ objfile.
+
+ */
+
+static void
+svr4_special_symbol_handling (void)
+{
+#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 = SOLIB_EXTRACT_ADDRESS (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 (SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_cp));
+ }
+
+#endif /* !SVR4_SHARED_LIBS */
+}
+
+/*
+
+ GLOBAL FUNCTION
+
+ svr4_solib_create_inferior_hook -- shared library startup support
+
+ SYNOPSIS
+
+ void svr4_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
+svr4_solib_create_inferior_hook (void)
+{
+ /* 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. current_sos 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;
+ }
+
+#if !defined(SVR4_SHARED_LIBS) || defined(_SCO_DS)
+ /* SCO and SunOS need the loop below, other systems should be using the
+ special shared library breakpoints and the shared library breakpoint
+ service routine.
+
+ 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;
+
+#if !defined(_SCO_DS)
+ /* 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");
+ }
+
+ if (auto_solib_add)
+ solib_add ((char *) 0, 0, (struct target_ops *) 0);
+#endif /* ! _SCO_DS */
+#endif
+}
+
+static void
+svr4_clear_solib (void)
+{
+ debug_base = 0;
+}
+
+static void
+svr4_free_so (struct so_list *so)
+{
+ free (so->lm_info->lm);
+ free (so->lm_info);
+}
+
+static struct target_so_ops svr4_so_ops;
+
+void
+_initialize_svr4_solib (void)
+{
+ svr4_so_ops.lm_addr = LM_ADDR;
+ svr4_so_ops.free_so = svr4_free_so;
+ svr4_so_ops.clear_solib = svr4_clear_solib;
+ svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook;
+ svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling;
+ svr4_so_ops.current_sos = svr4_current_sos;
+ svr4_so_ops.open_symbol_file_object = open_symbol_file_object;
+
+ /* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */
+ current_target_so_ops = &svr4_so_ops;
+}
+