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Use the newly provided aux vectors to get pagesize and osreldate information.

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Use local version of getpagesize(), rtld_getpagesize() in private allocator.
Override the __getosreldate() previously fetched from libc_pic.a with
local version that uses aux value if present. Note that __getosreldate()
is used by rtld indirectly, by mmap(2) libc wrapper.

To be able to utilize aux, split digest_dynamic() for use by init_rtld()
into two parts, where the first one does not call malloc(), and the
second part uses it. init_rtld() is able to initialize global variables
before digest_dynamic2() calls. In particular, pagesize and osreldate are
set up from the aux values.

Now, rtld avoids (two) sysctl calls in startup.

Tested by:	marius (sparc64)
MFC after:	1 month
This commit is contained in:
Konstantin Belousov 2010-08-17 09:05:39 +00:00
parent ee235befcb
commit d59a6353d7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=211413
2 changed files with 84 additions and 10 deletions
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23
libexec/rtld-elf/malloc.c
View File

@ -48,6 +48,7 @@ static char *rcsid = "$FreeBSD$";
*/
#include <sys/types.h>
#include <sys/sysctl.h>
#include <err.h>
#include <paths.h>
#include <stdarg.h>
@ -152,6 +153,26 @@ botch(s)
static void xprintf(const char *, ...);
#define TRACE() xprintf("TRACE %s:%d\n", __FILE__, __LINE__)
extern int pagesize;
static int
rtld_getpagesize(void)
{
int mib[2];
size_t size;
if (pagesize != 0)
return (pagesize);
mib[0] = CTL_HW;
mib[1] = HW_PAGESIZE;
size = sizeof(pagesize);
if (sysctl(mib, 2, &pagesize, &size, NULL, 0) == -1)
return (-1);
return (pagesize);
}
void *
malloc(nbytes)
size_t nbytes;
@ -166,7 +187,7 @@ malloc(nbytes)
* align break pointer so all data will be page aligned.
*/
if (pagesz == 0) {
pagesz = n = getpagesize();
pagesz = n = rtld_getpagesize();
if (morepages(NPOOLPAGES) == 0)
return NULL;
op = (union overhead *)(pagepool_start);

71
libexec/rtld-elf/rtld.c
View File

@ -40,6 +40,7 @@
#include <sys/mount.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <sys/utsname.h>
#include <sys/ktrace.h>
@ -84,6 +85,9 @@ typedef struct Struct_DoneList {
*/
static const char *basename(const char *);
static void die(void) __dead2;
static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
const Elf_Dyn **);
static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
static void digest_dynamic(Obj_Entry *, int);
static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
static Obj_Entry *dlcheck(void *);
@ -97,7 +101,7 @@ static char *find_library(const char *, const Obj_Entry *);
static const char *gethints(void);
static void init_dag(Obj_Entry *);
static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *);
static void init_rtld(caddr_t);
static void init_rtld(caddr_t, Elf_Auxinfo **);
static void initlist_add_neededs(Needed_Entry *, Objlist *);
static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
static bool is_exported(const Elf_Sym *);
@ -188,6 +192,8 @@ extern Elf_Dyn _DYNAMIC;
#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
#endif
int osreldate, pagesize;
/*
* These are the functions the dynamic linker exports to application
* programs. They are the only symbols the dynamic linker is willing
@ -350,7 +356,7 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
/* Initialize and relocate ourselves. */
assert(aux_info[AT_BASE] != NULL);
init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
__progname = obj_rtld.path;
argv0 = argv[0] != NULL ? argv[0] : "(null)";
@ -737,14 +743,16 @@ die(void)
* information in its Obj_Entry structure.
*/
static void
digest_dynamic(Obj_Entry *obj, int early)
digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
const Elf_Dyn **dyn_soname)
{
const Elf_Dyn *dynp;
Needed_Entry **needed_tail = &obj->needed;
const Elf_Dyn *dyn_rpath = NULL;
const Elf_Dyn *dyn_soname = NULL;
int plttype = DT_REL;
*dyn_rpath = NULL;
*dyn_soname = NULL;
obj->bind_now = false;
for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
switch (dynp->d_tag) {
@ -868,11 +876,11 @@ digest_dynamic(Obj_Entry *obj, int early)
* We have to wait until later to process this, because we
* might not have gotten the address of the string table yet.
*/
dyn_rpath = dynp;
*dyn_rpath = dynp;
break;
case DT_SONAME:
dyn_soname = dynp;
*dyn_soname = dynp;
break;
case DT_INIT:
@ -961,6 +969,12 @@ digest_dynamic(Obj_Entry *obj, int early)
obj->pltrelasize = obj->pltrelsize;
obj->pltrelsize = 0;
}
}
static void
digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
const Elf_Dyn *dyn_soname)
{
if (obj->z_origin && obj->origin_path == NULL) {
obj->origin_path = xmalloc(PATH_MAX);
@ -978,6 +992,16 @@ digest_dynamic(Obj_Entry *obj, int early)
object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
}
static void
digest_dynamic(Obj_Entry *obj, int early)
{
const Elf_Dyn *dyn_rpath;
const Elf_Dyn *dyn_soname;
digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
digest_dynamic2(obj, dyn_rpath, dyn_soname);
}
/*
* Process a shared object's program header. This is used only for the
* main program, when the kernel has already loaded the main program
@ -1304,9 +1328,11 @@ init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
* this function is to relocate the dynamic linker.
*/
static void
init_rtld(caddr_t mapbase)
init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
{
Obj_Entry objtmp; /* Temporary rtld object */
const Elf_Dyn *dyn_rpath;
const Elf_Dyn *dyn_soname;
/*
* Conjure up an Obj_Entry structure for the dynamic linker.
@ -1323,7 +1349,7 @@ init_rtld(caddr_t mapbase)
#endif
if (RTLD_IS_DYNAMIC()) {
objtmp.dynamic = rtld_dynamic(&objtmp);
digest_dynamic(&objtmp, 1);
digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
assert(objtmp.needed == NULL);
#if !defined(__mips__)
/* MIPS and SH{3,5} have a bogus DT_TEXTREL. */
@ -1344,6 +1370,13 @@ init_rtld(caddr_t mapbase)
/* Now that non-local variables can be accesses, copy out obj_rtld. */
memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
if (aux_info[AT_PAGESZ] != NULL)
pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
if (aux_info[AT_OSRELDATE] != NULL)
osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
/* Replace the path with a dynamically allocated copy. */
obj_rtld.path = xstrdup(PATH_RTLD);
@ -3630,3 +3663,23 @@ fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
}
return NULL;
}
int
__getosreldate(void)
{
size_t len;
int oid[2];
int error, osrel;
if (osreldate != 0)
return (osreldate);
oid[0] = CTL_KERN;
oid[1] = KERN_OSRELDATE;
osrel = 0;
len = sizeof(osrel);
error = sysctl(oid, 2, &osrel, &len, NULL, 0);
if (error == 0 && osrel > 0 && len == sizeof(osrel))
osreldate = osrel;
return (osreldate);
}