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authorRoland McGrath <roland@gnu.org>1996-06-05 01:07:21 +0000
committerRoland McGrath <roland@gnu.org>1996-06-05 01:07:21 +0000
commitee188d555b8c32ad9704a7440cab400af967292f (patch)
tree037a4821d35c11f2bbf89e7e71dc43dada67b166 /elf/dl-lookup.c
parentf68b86cc7bdcee246296d49f3a3318c1b97693f0 (diff)
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Tue Jun 4 21:01:20 1996 Roland McGrath <roland@delasyd.gnu.ai.mit.edu>
* sysdeps/mach/hurd/getlogin_r.c: New file. Wed Jun 5 02:11:30 1996 Ulrich Drepper <drepper@cygnus.com> * io/Makefile (routines): Add ttyname_r. * resolv/res_debug.c, resolv/resolv.h: Update from bind-4.3.4-T4A. * sysdeps/libm-i387/e_asinl.S, sysdeps/libm-i387/e_atan2l.S, sysdeps/libm-i387/e_expl.S, sysdeps/libm-i387/e_fmodl.S, sysdeps/libm-i387/e_log10l.S, sysdeps/libm-i387/e_logl.S, sysdeps/libm-i387/e_remainderl.S, sysdeps/libm-i387/e_scalbl.S, sysdeps/libm-i387/e_sqrtl.S, sysdeps/libm-i387/s_atanl.S, sysdeps/libm-i387/s_cosl.S, sysdeps/libm-i387/s_ilogbl.S, sysdeps/libm-i387/s_log1pl.S, sysdeps/libm-i387/s_logbl.S, sysdeps/libm-i387/s_scalbnl.S, sysdeps/libm-i387/s_sinl.S, sysdeps/libm-i387/s_tanl.S: New files. i387 assembler versions of `long double' math functions. * sysdeps/libm-ieee754/k_standard.c: Add handling for errors in long double functions. * sysdeps/libm-ieee754/s_ilogbl.c, sysdeps/libm-ieee754/s_logbl.c, sysdeps/libm-ieee754/s_modfl.c: New files. Generic versions of `long double' math functions. * sysdeps/libm-ieee754/s_isinf.c [NO_LONG_DOUBLE]: Add string alias for __isinfl. * sysdeps/libm-ieee754/w_acoshl.c, sysdeps/libm-ieee754/w_acosl.c, sysdeps/libm-ieee754/w_asinl.c, sysdeps/libm-ieee754/w_atan2l.c, sysdeps/libm-ieee754/w_atanhl.c, sysdeps/libm-ieee754/w_cabsl.c, sysdeps/libm-ieee754/w_coshl.c, sysdeps/libm-ieee754/w_dreml.c, sysdeps/libm-ieee754/w_expl.c, sysdeps/libm-ieee754/w_fmodl.c, sysdeps/libm-ieee754/w_gammal.c, sysdeps/libm-ieee754/w_gammal_r.c, sysdeps/libm-ieee754/w_hypotl.c, sysdeps/libm-ieee754/w_j0l.c, sysdeps/libm-ieee754/w_j1l.c, sysdeps/libm-ieee754/w_jnl.c, sysdeps/libm-ieee754/w_lgammal.c, sysdeps/libm-ieee754/w_lgammal_r.c, sysdeps/libm-ieee754/w_log10l.c, sysdeps/libm-ieee754/w_logl.c, sysdeps/libm-ieee754/w_powl.c, sysdeps/libm-ieee754/w_remainderl.c, sysdeps/libm-ieee754/w_scalbl.c, sysdeps/libm-ieee754/w_sinhl.c, sysdeps/libm-ieee754/w_sqrtl.c: New files. Wrapper functions around long double function implementations. * sysdeps/posix/ttyname_r.c (ttyname_r): Use _D_EXACT_NAMLEN to determine length of directory entry name. * posix/Makefile (routines): Add getlogin_r. * posix/unistd.h: Add prototype for getlogin_r. * sysdeps/stub/getlogin_r.c: New file. Reentrant version of getlogin function, specified in P1003.1c/D6. Stub version. * sysdeps/unix/getlogin.c (getlogin): Use ttyname_r instead of ttyname. This avoids saving and restoring the old content. Also use setutent_r, getutline_r and endutent_r instead of accing UTMP file directly. * sysdeps/unix/getlogin_r.c: New file. Reentrant version of getlogin function, specified in P1003.1c/D6. Tue Jun 4 20:10:09 1996 J.T. Conklin <jtc@cygnus.com> * sysdeps/libm-i387/s_finitef.S: Fix mask for exponent. * elf/dl-lookup.c (_dl_lookup_symbol): Grok magical undefined symbols _GNU_libc_dl_{open,close,symbol} and resolve them to dl functions. * elf/rtld.c (rtld_map): Renamed to _dl_rtld_map, made global. * elf/link.h: Declare _dl_rtld_map. * elf/dl-lookup.c (_dl_symbol_value): New function. * elf/link.h: Declare it. stdio-common/vfscanf.c: Prepare for reentrant libio. Used in reentrant libio.
Diffstat (limited to 'elf/dl-lookup.c')
-rw-r--r--elf/dl-lookup.c50
1 files changed, 45 insertions, 5 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index 26357c2..b2e9bff 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -110,11 +110,39 @@ _dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref,
if (weak_value.s == NULL && ELF32_ST_BIND ((*ref)->st_info) != STB_WEAK)
{
- const char msg[] = "undefined symbol: ";
- char buf[sizeof msg + strlen (undef_name)];
- memcpy (buf, msg, sizeof msg - 1);
- memcpy (&buf[sizeof msg - 1], undef_name, sizeof buf - sizeof msg + 1);
- _dl_signal_error (0, reference_name, buf);
+ /* The symbol was not defined by any object in scope. To allow
+ access to dynamic linker functionality without using -ldl and
+ thereby brining the dynamic linker's symbols into scope, we
+ recognize a few magical symbol names and resolve them to the
+ addresses of functions inside the dynamic linker. */
+
+ struct magic
+ {
+ unsigned long int hash;
+ const char *name;
+ Elf32_Addr value;
+ };
+ static struct magic magic[] =
+ {
+ { 0xd6a2a5e, "_GNU_libc_dl_open", (Elf32_Addr) &_dl_open },
+ { 0x69ef845, "_GNU_libc_dl_close", (Elf32_Addr) &_dl_close },
+ { 0xae4d63c, "_GNU_libc_dl_symbol", (Elf32_Addr) &_dl_symbol_value },
+ { 0, NULL, 0 }
+ };
+ struct magic *m;
+
+ for (m = magic; m->hash; ++m)
+ if (hash == m->hash && !strcmp (name, m->name))
+ return m->value;
+
+ {
+ const char msg[] = "undefined symbol: ";
+ char buf[sizeof msg + strlen (undef_name)];
+ memcpy (buf, msg, sizeof msg - 1);
+ memcpy (&buf[sizeof msg - 1], undef_name,
+ sizeof buf - sizeof msg + 1);
+ _dl_signal_error (0, reference_name, buf);
+ }
}
*ref = weak_value.s;
@@ -135,3 +163,15 @@ _dl_setup_hash (struct link_map *map)
hash += map->l_nbuckets;
map->l_chain = hash;
}
+
+/* Look up symbol NAME in MAP's scope and return its run-time address. */
+
+Elf32_Addr
+_dl_symbol_value (struct link_map *map, const char *name)
+{
+ Elf32_Addr loadbase;
+ const Elf32_Sym *ref = NULL;
+ struct link_map *scope[2] = { map, NULL };
+ loadbase = _dl_lookup_symbol (name, &ref, scope, map->l_name, 0, 0);
+ return loadbase + ref->st_value;
+}