#endif /* !SVR4_SHARED_LIBS */
}
+/* Relocate the main executable. This function should be called upon
+ stopping the inferior process at the entry point to the program.
+ The entry point from BFD is compared to the PC and if they are
+ different, the main executable is relocated by the proper amount.
+
+ As written it will only attempt to relocate executables which
+ lack interpreter sections. It seems likely that only dynamic
+ linker executables will get relocated, though it should work
+ properly for a position-independent static executable as well. */
+
+static void
+svr4_relocate_main_executable (void)
+{
+ asection *interp_sect;
+ CORE_ADDR pc = read_pc ();
+
+ /* Decide if the objfile needs to be relocated. As indicated above,
+ we will only be here when execution is stopped at the beginning
+ of the program. Relocation is necessary if the address at which
+ we are presently stopped differs from the start address stored in
+ the executable AND there's no interpreter section. The condition
+ regarding the interpreter section is very important because if
+ there *is* an interpreter section, execution will begin there
+ instead. When there is an interpreter section, the start address
+ is (presumably) used by the interpreter at some point to start
+ execution of the program.
+
+ If there is an interpreter, it is normal for it to be set to an
+ arbitrary address at the outset. The job of finding it is
+ handled in enable_break().
+
+ So, to summarize, relocations are necessary when there is no
+ interpreter section and the start address obtained from the
+ executable is different from the address at which GDB is
+ currently stopped.
+
+ [ The astute reader will note that we also test to make sure that
+ the executable in question has the DYNAMIC flag set. It is my
+ opinion that this test is unnecessary (undesirable even). It
+ was added to avoid inadvertent relocation of an executable
+ whose e_type member in the ELF header is not ET_DYN. There may
+ be a time in the future when it is desirable to do relocations
+ on other types of files as well in which case this condition
+ should either be removed or modified to accomodate the new file
+ type. (E.g, an ET_EXEC executable which has been built to be
+ position-independent could safely be relocated by the OS if
+ desired. It is true that this violates the ABI, but the ABI
+ has been known to be bent from time to time.) - Kevin, Nov 2000. ]
+ */
+
+ interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
+ if (interp_sect == NULL
+ && (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0
+ && bfd_get_start_address (exec_bfd) != pc)
+ {
+ struct cleanup *old_chain;
+ struct section_offsets *new_offsets;
+ int i, changed;
+ CORE_ADDR displacement;
+
+ /* It is necessary to relocate the objfile. The amount to
+ relocate by is simply the address at which we are stopped
+ minus the starting address from the executable.
+
+ We relocate all of the sections by the same amount. This
+ behavior is mandated by recent editions of the System V ABI.
+ According to the System V Application Binary Interface,
+ Edition 4.1, page 5-5:
+
+ ... Though the system chooses virtual addresses for
+ individual processes, it maintains the segments' relative
+ positions. Because position-independent code uses relative
+ addressesing between segments, the difference between
+ virtual addresses in memory must match the difference
+ between virtual addresses in the file. The difference
+ between the virtual address of any segment in memory and
+ the corresponding virtual address in the file is thus a
+ single constant value for any one executable or shared
+ object in a given process. This difference is the base
+ address. One use of the base address is to relocate the
+ memory image of the program during dynamic linking.
+
+ The same language also appears in Edition 4.0 of the System V
+ ABI and is left unspecified in some of the earlier editions. */
+
+ displacement = pc - bfd_get_start_address (exec_bfd);
+ changed = 0;
+
+ new_offsets = xcalloc (sizeof (struct section_offsets),
+ symfile_objfile->num_sections);
+ old_chain = make_cleanup (free, new_offsets);
+
+ for (i = 0; i < symfile_objfile->num_sections; i++)
+ {
+ if (displacement != ANOFFSET (symfile_objfile->section_offsets, i))
+ changed = 1;
+ new_offsets->offsets[i] = displacement;
+ }
+
+ if (changed)
+ objfile_relocate (symfile_objfile, new_offsets);
+
+ do_cleanups (old_chain);
+ }
+}
+
/*
GLOBAL FUNCTION
Also, what if child has exit()ed? Must exit loop somehow.
*/
-void
+static void
svr4_solib_create_inferior_hook (void)
{
+ /* Relocate the main executable if necessary. */
+ svr4_relocate_main_executable ();
+
/* 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
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