svn commit: r343093 - in head: include lib/libc/gen libexec/rtld-elf
Dag-Erling Smørgrav
des at FreeBSD.org
Wed Jan 16 12:12:41 UTC 2019
Author: des
Date: Wed Jan 16 12:12:40 2019
New Revision: 343093
URL: https://svnweb.freebsd.org/changeset/base/343093
Log:
Implement dlopenat(3).
MFC after: 3 weeks
Modified:
head/include/dlfcn.h
head/lib/libc/gen/dlopen.3
head/libexec/rtld-elf/rtld.c
Modified: head/include/dlfcn.h
==============================================================================
--- head/include/dlfcn.h Wed Jan 16 12:11:29 2019 (r343092)
+++ head/include/dlfcn.h Wed Jan 16 12:12:40 2019 (r343093)
@@ -120,6 +120,7 @@ void *dlopen(const char *, int);
void *dlsym(void * __restrict, const char * __restrict);
#if __BSD_VISIBLE
+void *dlopenat(int, const char *, int);
void *fdlopen(int, int);
int dladdr(const void * __restrict, Dl_info * __restrict);
dlfunc_t dlfunc(void * __restrict, const char * __restrict);
Modified: head/lib/libc/gen/dlopen.3
==============================================================================
--- head/lib/libc/gen/dlopen.3 Wed Jan 16 12:11:29 2019 (r343092)
+++ head/lib/libc/gen/dlopen.3 Wed Jan 16 12:12:40 2019 (r343093)
@@ -32,11 +32,12 @@
.\" @(#) dlopen.3 1.6 90/01/31 SMI
.\" $FreeBSD$
.\"
-.Dd January 2, 2019
+.Dd January 15, 2019
.Dt DLOPEN 3
.Os
.Sh NAME
.Nm dlopen ,
+.Nm dlopenat ,
.Nm fdlopen ,
.Nm dlsym ,
.Nm dlvsym ,
@@ -51,6 +52,8 @@
.Ft void *
.Fn dlopen "const char *path" "int mode"
.Ft void *
+.Fn dlopenat "int fd" "const char *path" "int mode"
+.Ft void *
.Fn fdlopen "int fd" "int mode"
.Ft void *
.Fn dlsym "void * restrict handle" "const char * restrict symbol"
@@ -169,6 +172,24 @@ If
fails, it returns a null pointer, and sets an error condition which may
be interrogated with
.Fn dlerror .
+.Pp
+The
+.Fn dlopenat
+function is equivalent to
+.Fn dlopen
+except in the case where the path specifies a relative path.
+In this case the file to be opened is determined relative to the
+directory associated with the file descriptor fd instead of the
+current working directory.
+If
+.Fn dlopenat
+is passed the special value
+.Dv AT_FDCWD
+in the
+.Fa fd
+parameter, the current working directory is used and the behavior is
+identical to a call to
+.Fn dlopen .
.Pp
The
.Fn fdlopen
Modified: head/libexec/rtld-elf/rtld.c
==============================================================================
--- head/libexec/rtld-elf/rtld.c Wed Jan 16 12:11:29 2019 (r343092)
+++ head/libexec/rtld-elf/rtld.c Wed Jan 16 12:12:40 2019 (r343093)
@@ -93,8 +93,8 @@ 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 *);
static int dlclose_locked(void *, RtldLockState *);
-static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
- int lo_flags, int mode, RtldLockState *lockstate);
+static Obj_Entry *dlopen_object(int, const char *name, int fd,
+ Obj_Entry *refobj, int lo_flags, int mode, RtldLockState *lockstate);
static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
static bool donelist_check(DoneList *, const Obj_Entry *);
@@ -118,7 +118,7 @@ static void load_filtees(Obj_Entry *, int flags, RtldL
static void unload_filtees(Obj_Entry *, RtldLockState *);
static int load_needed_objects(Obj_Entry *, int);
static int load_preload_objects(void);
-static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
+static Obj_Entry *load_object(int, const char *, int, const Obj_Entry *, int);
static void map_stacks_exec(RtldLockState *);
static int obj_disable_relro(Obj_Entry *);
static int obj_enforce_relro(Obj_Entry *);
@@ -147,7 +147,7 @@ static int relocate_objects(Obj_Entry *, bool, Obj_Ent
static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
static int rtld_dirname(const char *, char *);
static int rtld_dirname_abs(const char *, char *);
-static void *rtld_dlopen(const char *name, int fd, int mode);
+static void *rtld_dlopen(int, const char *name, int fd, int mode);
static void rtld_exit(void);
static char *search_library_path(const char *, const char *, const char *,
int *);
@@ -231,6 +231,7 @@ extern Elf_Dyn _DYNAMIC;
int dlclose(void *) __exported;
char *dlerror(void) __exported;
void *dlopen(const char *, int) __exported;
+void *dlopenat(int, const char *, int) __exported;
void *fdlopen(int, int) __exported;
void *dlsym(void *, const char *) __exported;
dlfunc_t dlfunc(void *, const char *) __exported;
@@ -2292,8 +2293,8 @@ load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int
{
for (; needed != NULL; needed = needed->next) {
- needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
- flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
+ needed->obj = dlopen_object(AT_FDCWD, obj->strtab + needed->name, -1,
+ obj, flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
RTLD_LOCAL, lockstate);
}
}
@@ -2316,8 +2317,8 @@ process_needed(Obj_Entry *obj, Needed_Entry *needed, i
Obj_Entry *obj1;
for (; needed != NULL; needed = needed->next) {
- obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
- flags & ~RTLD_LO_NOLOAD);
+ obj1 = needed->obj = load_object(AT_FDCWD, obj->strtab + needed->name,
+ -1, obj, flags & ~RTLD_LO_NOLOAD);
if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
return (-1);
}
@@ -2360,7 +2361,7 @@ load_preload_objects(void)
savech = p[len];
p[len] = '\0';
- obj = load_object(p, -1, NULL, 0);
+ obj = load_object(AT_FDCWD, p, -1, NULL, 0);
if (obj == NULL)
return -1; /* XXX - cleanup */
obj->z_interpose = true;
@@ -2389,7 +2390,8 @@ printable_path(const char *path)
* on failure.
*/
static Obj_Entry *
-load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
+load_object(int atfd, const char *name, int fd_u, const Obj_Entry *refobj,
+ int flags)
{
Obj_Entry *obj;
int fd;
@@ -2426,7 +2428,7 @@ load_object(const char *name, int fd_u, const Obj_Entr
* To avoid a race, we open the file and use fstat() rather than
* using stat().
*/
- if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
+ if ((fd = openat(atfd, path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
_rtld_error("Cannot open \"%s\"", path);
free(path);
return (NULL);
@@ -3255,21 +3257,28 @@ dllockinit(void *context,
}
void *
+dlopenat(int fd, const char *name, int mode)
+{
+
+ return (rtld_dlopen(fd, name, -1, mode));
+}
+
+void *
dlopen(const char *name, int mode)
{
- return (rtld_dlopen(name, -1, mode));
+ return (rtld_dlopen(AT_FDCWD, name, -1, mode));
}
void *
fdlopen(int fd, int mode)
{
- return (rtld_dlopen(NULL, fd, mode));
+ return (rtld_dlopen(AT_FDCWD, NULL, fd, mode));
}
static void *
-rtld_dlopen(const char *name, int fd, int mode)
+rtld_dlopen(int atfd, const char *name, int fd, int mode)
{
RtldLockState lockstate;
int lo_flags;
@@ -3291,7 +3300,7 @@ rtld_dlopen(const char *name, int fd, int mode)
if (ld_tracing != NULL)
lo_flags |= RTLD_LO_TRACE;
- return (dlopen_object(name, fd, obj_main, lo_flags,
+ return (dlopen_object(atfd, name, fd, obj_main, lo_flags,
mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
}
@@ -3306,8 +3315,8 @@ dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstat
}
static Obj_Entry *
-dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
- int mode, RtldLockState *lockstate)
+dlopen_object(int atfd, const char *name, int fd, Obj_Entry *refobj,
+ int lo_flags, int mode, RtldLockState *lockstate)
{
Obj_Entry *old_obj_tail;
Obj_Entry *obj;
@@ -3329,7 +3338,7 @@ dlopen_object(const char *name, int fd, Obj_Entry *ref
obj = obj_main;
obj->refcount++;
} else {
- obj = load_object(name, fd, refobj, lo_flags);
+ obj = load_object(atfd, name, fd, refobj, lo_flags);
}
if (obj) {
More information about the svn-src-all
mailing list