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author | peter <peter@FreeBSD.org> | 2001-06-13 10:58:39 +0000 |
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committer | peter <peter@FreeBSD.org> | 2001-06-13 10:58:39 +0000 |
commit | f10fa038c14063eaf2da32ed734e644e5f569694 (patch) | |
tree | 88aef8097c80f09c2f725d61b6da4d433a595a61 /sys/kern/link_elf_obj.c | |
parent | 2514663dd721b9ac234d35a4dac65dfc457ff6bc (diff) | |
download | FreeBSD-src-f10fa038c14063eaf2da32ed734e644e5f569694.zip FreeBSD-src-f10fa038c14063eaf2da32ed734e644e5f569694.tar.gz |
With this commit, I hereby pronounce gensetdefs past its use-by date.
Replace the a.out emulation of 'struct linker_set' with something
a little more flexible. <sys/linker_set.h> now provides macros for
accessing elements and completely hides the implementation.
The linker_set.h macros have been on the back burner in various
forms since 1998 and has ideas and code from Mike Smith (SET_FOREACH()),
John Polstra (ELF clue) and myself (cleaned up API and the conversion
of the rest of the kernel to use it).
The macros declare a strongly typed set. They return elements with the
type that you declare the set with, rather than a generic void *.
For ELF, we use the magic ld symbols (__start_<setname> and
__stop_<setname>). Thanks to Richard Henderson <rth@redhat.com> for the
trick about how to force ld to provide them for kld's.
For a.out, we use the old linker_set struct.
NOTE: the item lists are no longer null terminated. This is why
the code impact is high in certain areas.
The runtime linker has a new method to find the linker set
boundaries depending on which backend format is in use.
linker sets are still module/kld unfriendly and should never be used
for anything that may be modular one day.
Reviewed by: eivind
Diffstat (limited to 'sys/kern/link_elf_obj.c')
-rw-r--r-- | sys/kern/link_elf_obj.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/sys/kern/link_elf_obj.c b/sys/kern/link_elf_obj.c index 32f45ce..da7462a 100644 --- a/sys/kern/link_elf_obj.c +++ b/sys/kern/link_elf_obj.c @@ -108,6 +108,8 @@ static int link_elf_search_symbol(linker_file_t, caddr_t value, static void link_elf_unload_file(linker_file_t); static void link_elf_unload_preload(linker_file_t); +static int link_elf_lookup_set(linker_file_t, const char *, + void ***, void ***, int *); static kobj_method_t link_elf_methods[] = { KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), @@ -117,6 +119,7 @@ static kobj_method_t link_elf_methods[] = { KOBJMETHOD(linker_load_file, link_elf_load_file), KOBJMETHOD(linker_link_preload, link_elf_link_preload), KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), + KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), { 0, 0 } }; @@ -1075,3 +1078,61 @@ link_elf_search_symbol(linker_file_t lf, caddr_t value, return 0; } + +/* + * Look up a linker set on an ELF system. + */ +static int +link_elf_lookup_set(linker_file_t lf, const char *name, + void ***startp, void ***stopp, int *countp) +{ + c_linker_sym_t sym; + linker_symval_t symval; + char *setsym; + void **start, **stop; + int len, error = 0, count; + + len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ + setsym = malloc(len, M_LINKER, M_WAITOK); + if (setsym == NULL) + return ENOMEM; + + /* get address of first entry */ + snprintf(setsym, len, "%s%s", "__start_set_", name); + error = link_elf_lookup_symbol(lf, setsym, &sym); + if (error) + goto out; + link_elf_symbol_values(lf, sym, &symval); + if (symval.value == 0) { + error = ESRCH; + goto out; + } + start = (void **)symval.value; + + /* get address of last entry */ + snprintf(setsym, len, "%s%s", "__stop_set_", name); + error = link_elf_lookup_symbol(lf, setsym, &sym); + if (error) + goto out; + link_elf_symbol_values(lf, sym, &symval); + if (symval.value == 0) { + error = ESRCH; + goto out; + } + stop = (void **)symval.value; + + /* and the number of entries */ + count = stop - start; + + /* and copy out */ + if (startp) + *startp = start; + if (stopp) + *stopp = stop; + if (countp) + *countp = count; + +out: + free(setsym, M_LINKER); + return error; +} |