Commit Graph

41 Commits

Author SHA1 Message Date
Konstantin Belousov
ca2560bd85 rtld: fix typo in comment
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
2022-10-17 17:10:03 +03:00
Konstantin Belousov
1251cf8a30 rtld-elf/libmap.c: correct comment
There is no intent to support TLS for rtld.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2022-09-19 01:49:41 +03:00
Konstantin Belousov
33dba3bb0e rtld-elf/paths.h: Make it usable outside rtld
but still for tightly coupled things like ldd(1)

Rename paths.h to rtld_paths.h.
Add guard for rtld-specific externs declarations.
Add _COMPAT32_BASENAME_RTLD and _COMPAT32_PATH_RTLD.

Reviewed by:	arichardson, jhb
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D32464
2021-10-21 03:08:54 +03:00
Konstantin Belousov
aa68b3bb2e rtld: constify most variables holding references to the environment values
Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D31545
2021-08-17 15:06:08 +03:00
Konstantin Belousov
741d78126b rtld: call close(2) after errno is saved
to prevent obliteration of error value from the original syscall.
Also improve error message for short read.

Submitted by:	Konrad Sewiłło-Jopek
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D27864
2021-01-02 04:43:32 +02:00
Alex Richardson
b54a59f3ba Reduce size of rtld by 22% by pulling in less code from libc
Currently RTLD is linked against libc_nossp_pic which means that any libc
symbol used in rtld can pull in a lot of depedencies. This was causing
symbol such as __libc_interposing and all the pthread stubs to be included
in RTLD even though they are not required. It turns out most of these
dependencies can easily be avoided by providing overrides inside of rtld.

This change is motivated by CHERI, where we have an experimental ABI that
requires additional relocation processing to allow the use of function
pointers inside of rtld. Instead of adding this self-relocation code to
RTLD I attempted to remove most function pointers from RTLD and discovered
that most of them came from the libc dependencies instead of being actually
used inside rtld.

A nice side-effect of this change is that rtld is now 22% smaller on amd64.

   text	   data	    bss	    dec	    hex	filename
0x21eb6	  0xce0	  0xe60	 145910	  239f6	/home/alr48/ld-elf-x86.before.so.1
0x1a6ed	  0x728	  0xdd8	 113645	  1bbed	/home/alr48/ld-elf-x86.after.so.1

The number of R_X86_64_RELATIVE relocations that need to be processed on
startup has also gone down from 368 to 187 (almost 50% less).

Reviewed By:	kib
Differential Revision: https://reviews.freebsd.org/D20663
2019-06-30 11:49:58 +00:00
Alex Richardson
3ab5b6bd97 rtld-elf: fix more warnings to allow compiling with WARNS=6
Reviewed By:	kib
Approved By:	brooks (mentor)
Differential Revision: https://reviews.freebsd.org/D17154
2018-10-29 21:08:28 +00:00
Alex Richardson
903e0ffd07 rtld-elf: compile with WANRS=4 warnings other than -Wcast-align
Reviewed By:	kib
Approved By:	brooks (mentor)
Differential Revision: https://reviews.freebsd.org/D17153
2018-10-29 21:08:19 +00:00
Alex Richardson
78b648465d rtld-elf: make it compile with WARNS=3
Reviewed By:	kib
Approved By:	brooks (mentor)
Differential Revision: https://reviews.freebsd.org/D17150
2018-10-29 21:08:11 +00:00
Konstantin Belousov
6c30676522 When doing lm_add(), check for duplicates.
This is useful when lm_find() moves the match to the global mapping,
since lm_find() could be called with a same path more than once.

Reported and tested by:	Andreas Longwitz <longwitz@incore.de>
Sponsored by:	The FreeBSD Foundation
Approved by:	re (gjb)
MFC after:	1 week
2018-09-26 21:27:08 +00:00
Konstantin Belousov
c1a0a86ed4 Style cleanup. No functional changes.
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
Approved by:    re (rgrimes)
2018-09-02 15:42:37 +00:00
Edward Tomasz Napierala
152036a0f7 Plug memory leak on error case.
Reported by:	Coverity
CID:		1382112
MFC after:	2 weeks
2017-10-29 12:07:27 +00:00
Edward Tomasz Napierala
a8b31c14d2 Use xmalloc and read(2) instead of mmap(2) to read in libmap.conf(5).
This removes the need to call munmap(2) afterwards.

MFC after:	2 weeks
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D12767
2017-10-24 10:48:26 +00:00
Edward Tomasz Napierala
6b61e3e47a Don't call realpath(3) from libmap rtld code. This gets rid of a few calls
to fstatat(2) at binary startup; the difference looks like this:

--- przed       2017-10-14 13:55:49.983528000 +0100
+++ po  2017-10-14 14:10:39.134343000 +0100
@@ -1,15 +1,10 @@
 mmap(0x0,32768,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANON,-1,0x0) = 34366173184 (0x800623000)
 issetugid()                                     = 0 (0x0)
-fstatat(AT_FDCWD,"/etc",{ mode=drwxr-xr-x ,inode=1364352,size=2560,blksize=32768 },AT_SYMLINK_NOFOLLOW) = 0 (0x0)
-fstatat(AT_FDCWD,"/etc/libmap.conf",{ mode=-rw-r--r-- ,inode=1373288,size=102,blksize=32768 },AT_SYMLINK_NOFOLLOW) = 0 (0x0)
 openat(AT_FDCWD,"/etc/libmap.conf",O_RDONLY|O_CLOEXEC,00) = 3 (0x3)
 fstat(3,{ mode=-rw-r--r-- ,inode=1373288,size=102,blksize=32768 }) = 0 (0x0)
 mmap(0x0,102,PROT_READ,MAP_PRIVATE,3,0x0)       = 34366205952 (0x80062b000)
 close(3)                                        = 0 (0x0)
-fstatat(AT_FDCWD,"/usr",{ mode=drwxr-xr-x ,inode=561792,size=512,blksize=32768 },AT_SYMLINK_NOFOLLOW) = 0 (0x0)
-fstatat(AT_FDCWD,"/usr/local",{ mode=drwxr-xr-x ,inode=561800,size=512,blksize=32768 },AT_SYMLINK_NOFOLLOW) = 0 (0x0)
-fstatat(AT_FDCWD,"/usr/local/etc",{ mode=drwxr-xr-x ,inode=653279,size=1536,blksize=32768 },AT_SYMLINK_NOFOLLOW) = 0 (0x0)
-fstatat(AT_FDCWD,"/usr/local/etc/libmap.d",0x7fffffffcf50,AT_SYMLINK_NOFOLLOW) ERR#2 'No such file or directory'
+open("/usr/local/etc/libmap.d",O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC,0165) ERR#2 'No such file or directory'
 munmap(0x80062b000,102)                                 = 0 (0x0)
 openat(AT_FDCWD,"/var/run/ld-elf.so.hints",O_RDONLY|O_CLOEXEC,00) = 3 (0x3)
 read(3,"Ehnt\^A\0\0\0\M^@\0\0\0\M-2\0\0"...,128) = 128 (0x80)

Reviewed by:	kib
MFC after:	2 weeks
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D12741
2017-10-22 10:32:40 +00:00
Warner Losh
3deca56f3f Rather than using the #define for path names, indirect through a char *
variable that could change for different executable types detected.
2015-10-31 04:39:55 +00:00
Warner Losh
b2a4014cbb Move all the paths into a new path.h to centralize them. 2015-10-31 04:39:28 +00:00
Pedro F. Giffuni
0fa46a4231 Always check the limits of array index variables before using them.
Obtained from:	DragonFlyBSD
MFC after:	1 week
2014-08-21 02:40:33 +00:00
Konstantin Belousov
490c68de98 Fix LD_LIBMAP.
The r232862 passed the pointer to end of string to lmc_parse() and free().

Submitted by:	Wolfgang Jenkner <wjenkner@inode.at>
MFC after:	1 week
2014-05-18 17:14:08 +00:00
Dag-Erling Smørgrav
8182b3bee1 Make the directory mapping functionality, which was previously only
available in 32-bit compatibility mode, unconditional.

Overhaul the man page, which had evolved more by accretion than by design.

Approved by:	re (gjb)
MFC after:	3 weeks
2013-09-21 21:03:52 +00:00
Jilles Tjoelker
e194282943 rtld: Fix fd leak with parallel dlopen and fork/exec.
Rtld did not set FD_CLOEXEC on its internal file descriptors; therefore,
such a file descriptor may be passed to a process created by another thread
running in parallel to dlopen() or fdlopen().

No other threads are expected to be running during parsing of the hints
and libmap files but the file descriptors need not be passed to child
processes so add O_CLOEXEC there as well.

This change will break fdlopen() (as used by OpenPAM) on kernels without
F_DUPFD_CLOEXEC (added in July). Note that running new userland on old
kernels is not supported.

Reviewed by:	kib
2012-11-04 21:42:24 +00:00
Baptiste Daroussin
5c98f30724 open the resolved path
fix debug message

Submitted by:	John Marino <draco@marino.st>
Approved by:	des (mentor)
2012-05-05 16:37:14 +00:00
Baptiste Daroussin
faf66437f8 Add two special directives to libmap.conf:
include <file>:
  Parse the contents of file before continuing with the current file.
includedir <dir>:
  Parse the contents of every file in dir that ends in .conf before continuing
  with the current file.
Any file or directory encountered while processing include or includedir
directives will be parsed exactly once, even if it is encountered multiple
times.

Reviewed by:	kib, des
Approved by:	des (mentor)
MFC after:	1 month
2012-04-30 21:26:35 +00:00
Konstantin Belousov
6fea10fb9f Rtld on diet 3.
Stop using strerror(3) in rtld, which brings in msgcat and stdio.
Directly access sys_errlist array of errno messages with private
rtld_strerror() function.

Now,
$ size /libexec/ld-elf.so.1
   text    data     bss     dec     hex filename
  96983    2480    8744  108207   1a6af /libexec/ld-elf.so.1

Reviewed by:	dim, kan
MFC after:	2 weeks
2012-03-14 15:39:59 +00:00
Konstantin Belousov
68f1db20b3 Rtld on diet part 2:
Do not use stdio for libmap.conf read.  Directly map the file and
parse lines from the mappings.

Reviewed by:	kan
MFC after:	3 weeks
2012-03-12 12:16:08 +00:00
Sergey Kandaurov
44976acae3 Cosmetic nit:
- rename isspace1() macro to the more appropriate rtld_isspace().

Discussed with:	kib
2012-03-06 09:34:30 +00:00
Konstantin Belousov
b36070f555 The libmap.conf initialization is performed before TLS is functional.
Since after r232498 the ctype macros require working access to
thread-local variables, rtld crashes when libmap.conf is present.

Use hand-made isspace1() macro which is enough to detect spaces in
libmap.conf.

Reported by:	alc, lme, many on current@
Tested by:	lme
Reviewed by:	dim, kan
MFC after:	1 week
2012-03-05 20:43:06 +00:00
Peter Wemm
8c6a035ead Fix a malloc overrun in 32-bit compat libmap lookup code. 2006-01-31 06:08:28 +00:00
Matthew N. Dodd
5b08cb0449 Description from Dan:
Another handy libmap patch.  Lets you do stuff like this:

	LD_LIBMAP="libpthread.so.1=libthr.so.1" mythreadedapp

	If you already have a program-specific override in libmap.conf, note
	that you must use a program-specific override in LD_LIBMAP:

	LD_LIBMAP="[mythreadedapp],libpthread.so.1=libthr.so.1" mythreadedapp

PR:		bin/74471
Submitted by:	Dan Nelson <dnelson AT allantgroup.com>
MFC after:	2 weeks
2005-02-04 02:46:41 +00:00
Matthew N. Dodd
d33da23f4c style(9) 2005-02-04 02:13:37 +00:00
Matthew N. Dodd
966efcc767 Support basename and path based constrained matches.
eg:
	[foo]
	...

	matches any executable 'foo'

	[/usr/bin/foo/]
	...

	matches any executable under the directory /usr/bin/foo/

Exact matches continue to function as before.

PR:		 bin/66769
Submitted-by:	 Dan Nelson
2004-05-24 01:24:13 +00:00
Peter Wemm
c905e45dc0 Add initial support for compiling a special 32 bit version of
ld-elf.so.1 on 64 bit systems.  Most of this involves using alternate
paths, environment variables and diagnostic messages.

The build glue is seperate.
2004-03-21 01:21:26 +00:00
Max Khon
6e918a4d5e Fix "warning: value computed is not used".
Found by:	gcc 2.95.4 [FreeBSD]
2004-02-03 18:53:40 +00:00
Matthew N. Dodd
4402996dea Change libmap.c:lm_init() to return a status value; 0 for success
(libmap available) and 1 for failure.  Assign this return to the
global 'libmap_disable' variable in rtld.c.

This totally prevents any libmap functions from being called after
lm_init() if no config file is present.
2003-09-13 21:43:08 +00:00
Matthew N. Dodd
7227105f74 Include libmap.h for prototypes. 2003-06-18 05:31:08 +00:00
Matthew N. Dodd
1aac1ed634 Provide function entry debugging messages. 2003-05-31 14:46:38 +00:00
Matthew N. Dodd
1340fc1015 Don't post-increment pointers inside a loop conditional.
While I'm here:
- Let lm_add() call strdup() on its own behalf.
- Use a temporary pointer when parsing constraints; only set the
  constraint pointer on a totally successful match.

PR:		 bin/52783
Submitted by:	 David P. Reese Jr. <daver@gomerbud.com>
Approved by:	 re (rwatson)
2003-05-30 00:49:16 +00:00
Alexander Kabaev
6d5d786f80 Allow threading libraries to register their own locking
implementation in case default one provided by rtld is
not suitable.

Consolidate various identical MD lock implementation into
a single file using appropriate machine/atomic.h.

Approved by:	re (scottl)
2003-05-29 22:58:26 +00:00
Matthew N. Dodd
3467e8b8a0 - Use xmalloc() and xstrdup() instead of malloc() and strdup().
- Add a global mapping if we have a successful constrained match.

Approved by:	re
2003-05-19 07:10:12 +00:00
Alexander Kabaev
486089f00c Remove redundant strlen checks, do not check the same
symbol twice.
2003-04-30 19:05:53 +00:00
Matthew N. Dodd
623b6bd2f9 Code cleanups and sanity checking for config file parser. 2003-04-10 01:44:19 +00:00
Matthew N. Dodd
29ade36225 Dynamic object dependency mapping: libmap.
This is an optional feature, disabled by default.

This will be useful to people testing the various POSIX threading
libraries under -CURRENT but can easily serve other needs.
2003-04-07 16:21:26 +00:00