1# Copyright (C) 2010-2020 Free Software Foundation, Inc.
2
3# This program is free software; you can redistribute it and/or modify
4# it under the terms of the GNU General Public License as published by
5# the Free Software Foundation; either version 3 of the License, or
6# (at your option) any later version.
7#
8# This program is distributed in the hope that it will be useful,
9# but WITHOUT ANY WARRANTY; without even the implied warranty of
10# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11# GNU General Public License for more details.
12#
13# You should have received a copy of the GNU General Public License
14# along with this program.  If not, see <http://www.gnu.org/licenses/>.
15
16# Return nul-terminated string read from section SECTION of EXEC.  Return ""
17# if no such section or nul-terminated string was found.  Function is useful
18# for sections ".interp" or ".gnu_debuglink".
19
20proc section_get {exec section} {
21    global subdir
22    set tmp [standard_output_file section_get.tmp]
23    set objcopy_program [gdb_find_objcopy]
24
25    set command "exec $objcopy_program -O binary --set-section-flags $section=A --change-section-address $section=0 -j $section $exec $tmp"
26    verbose -log "command is $command"
27    set result [catch $command output]
28    verbose -log "result is $result"
29    verbose -log "output is $output"
30    if {$result == 1} {
31	return ""
32    }
33    set fi [open $tmp]
34    fconfigure $fi -translation binary
35    set data [read $fi]
36    close $fi
37    file delete $tmp
38    # .interp has size $len + 1 but .gnu_debuglink contains garbage after \000.
39    set len [string first \000 $data]
40    if {$len < 0} {
41	verbose -log "section $section not found"
42	return ""
43    }
44    set retval [string range $data 0 [expr $len - 1]]
45    verbose -log "section $section is <$retval>"
46    return $retval
47}
48
49# Resolve symlinks.
50
51proc symlink_resolve {file} {
52    set loop 0
53    while {[file type $file] == "link"} {
54	set target [file readlink $file]
55	if {[file pathtype $target] == "relative"} {
56	    set src2 [file dirname $file]/$target
57	} else {
58	    set src2 $target
59	}
60	verbose -log "Resolved symlink $file targetting $target as $src2"
61	set file $src2
62
63	set loop [expr $loop + 1]
64	if {$loop > 30} {
65	    fail "looping symlink resolution for $file"
66	    return ""
67	}
68    }
69    return $file
70}
71
72# Copy SRC to DEST, resolving any symlinks in SRC.  Return nonzero iff
73# the copy was succesful.
74#
75# This function is guaranteed to never raise any exception, even when the copy
76# fails.
77
78proc file_copy {src dest} {
79    set src [symlink_resolve $src]
80    # Test name would contain unstable directory name for symlink-unresolved
81    # $src.
82    set test "copy [file tail $src] to [file tail $dest]"
83    set command "file copy -force -- $src $dest"
84    verbose -log "command is $command"
85    if [catch $command] {
86	fail $test
87	return 0
88    } else {
89    	pass $test
90	return 1
91    }
92}
93
94# Wrap function build_executable so that the resulting executable is fully
95# self-sufficient (without dependencies on system libraries).  Parameter
96# INTERP may be used to specify a loader (ld.so) to be used that is
97# different from the default system one.  INTERP can be set to "no" if no ld.so
98# copy should be made.  Libraries on which the executable depends are copied
99# into directory DIR.  Default DIR value to
100# `${objdir}/${subdir}/${EXECUTABLE}.d'.
101#
102# In case of success, return a string containing the arguments to be used
103# in order to perform a prelink of the executable obtained.  Return the
104# empty string in case of failure.
105#
106# This can be useful when trying to prelink an executable which might
107# depend on system libraries.  To properly prelink an executable, all
108# of its dynamically linked libraries must be prelinked as well.  If
109# the executable depends on some system libraries, we may not have
110# sufficient write priviledges on these files to perform the prelink.
111# This is why we make a copy of these shared libraries, and link the
112# executable against these copies instead.
113#
114# Function recognizes only libraries listed by `ldd' after
115# its ` => ' separator.  That means $INTERP and any libraries not being linked
116# with -Wl,-soname,NAME.so are not copied.
117
118proc build_executable_own_libs {testname executable sources options {interp ""} {dir ""}} {
119    global subdir
120
121    if { ![isnative] } {
122	error "This proc can be only used for native target."
123    }
124
125    if {[build_executable $testname $executable $sources $options] == -1} {
126	return ""
127    }
128    set binfile [standard_output_file ${executable}]
129
130    set ldd [gdb_find_ldd]
131    set command "$ldd $binfile"
132    set test "ldd $executable"
133    set result [catch "exec $command" output]
134    verbose -log "result of $command is $result"
135    verbose -log "output of $command is $output"
136    if {$result != 0 || $output == ""} {
137	fail $test
138    } else {
139	pass $test
140    }
141
142    # gdb testsuite will put there also needless -lm.
143    set test "$test output contains libs"
144    set libs [regexp -all -inline -line {^.* => (/[^ ]+).*$} $output]
145    if {[llength $libs] == 0} {
146	fail $test
147    } else {
148	pass $test
149    }
150
151    if {$dir == ""} {
152	set dir ${binfile}.d
153    }
154    file delete -force -- $dir
155    file mkdir $dir
156
157    if {$interp == ""} {
158	set interp_system [section_get $binfile .interp]
159	if {$interp_system == ""} {
160	    fail "$test could not find .interp"
161	} else {
162	    set interp ${dir}/[file tail $interp_system]
163	    file_copy $interp_system $interp
164	}
165    }
166    if {$interp == "no"} {
167	set interp ""
168    }
169
170    set dests {}
171    foreach {trash abspath} $libs {
172	set dest "$dir/[file tail $abspath]"
173	file_copy $abspath $dest
174	lappend dests $dest
175    }
176
177    # Do not lappend it so that "-rpath $dir" overrides any possible "-rpath"s
178    # specified by the caller to be able to link it for ldd" above.
179    set options [linsert $options 0 "ldflags=-Wl,-rpath,$dir"]
180    if {$interp != ""} {
181	set options [linsert $options 0 "ldflags=-Wl,--dynamic-linker,$interp"]
182    }
183
184    if {[build_executable $testname $executable $sources $options] == -1} {
185	return ""
186    }
187
188    set prelink_args "--ld-library-path=$dir $binfile [concat $dests]"
189    if {$interp != ""} {
190	set prelink_args "--dynamic-linker=$interp $prelink_args $interp"
191    }
192    return $prelink_args
193}
194
195# Unprelink ARG.  Reported test name can be specified by NAME.  Return non-zero
196# on success, zero on failure.
197
198proc prelink_no {arg {name {}}} {
199    if {$name == ""} {
200	set name [file tail $arg]
201    }
202    set test "unprelink $name"
203    set command "exec /usr/sbin/prelink -uN $arg"
204    verbose -log "command is $command"
205    set result [catch $command output]
206    verbose -log "result is $result"
207    verbose -log "output is $output"
208    if {$result == 1 && [regexp {^(couldn't execute "/usr/sbin/prelink[^\r\n]*": no such file or directory\n?)*$} $output]} {
209	# Without prelink, at least verify that all the binaries do not
210	# contain the  ".gnu.prelink_undo" section (which would mean that they
211	# have already been prelinked).
212	set test "$test (missing /usr/sbin/prelink)"
213	foreach bin [split $arg] {
214	    if [string match "-*" $bin] {
215		# Skip prelink options.
216		continue
217	    }
218	    set readelf_program [gdb_find_readelf]
219	    set command "exec $readelf_program -WS $bin"
220	    verbose -log "command is $command"
221	    set result [catch $command output]
222	    verbose -log "result is $result"
223	    verbose -log "output is $output"
224	    if {$result != 0 || [string match {* .gnu.prelink_undo *} $output]} {
225		fail "$test ($bin is already prelinked)"
226		return 0
227	    }
228	}
229	pass $test
230	return 1
231    }
232    if {$result == 0 && $output == ""} {
233	verbose -log "$name has been now unprelinked"
234	set command "exec /usr/sbin/prelink -uN $arg"
235	verbose -log "command is $command"
236	set result [catch $command output]
237	verbose -log "result is $result"
238	verbose -log "output is $output"
239    }
240    # Last line does miss the trailing \n.  There can be multiple such messages
241    # as ARG may list multiple files.
242    if {$result == 1 && [regexp {^([^\r\n]*prelink[^\r\n]*: [^ ]* does not have .gnu.prelink_undo section\n?)*$} $output]} {
243	pass $test
244	return 1
245    } else {
246	fail $test
247	return 0
248    }
249}
250
251# Prelink ARG.  Reported test name can be specified by NAME.  Return non-zero
252# on success, zero on failure.
253
254proc prelink_yes {arg {name ""}} {
255    if {$name == ""} {
256	set name [file tail $arg]
257    }
258
259    # Try to unprelink it first so that, if it has been already prelinked
260    # before, we get a different address now, making the new result unaffected
261    # by any previous prelinking.
262    if ![prelink_no $arg "$name pre-unprelink"] {
263	return 0
264    }
265
266    set test "prelink $name"
267
268    # `--no-exec-shield' is for i386, where prelink in the exec-shield mode is
269    # forced to push all the libraries tight together, in order to fit into
270    # the first two memory areas (either the ASCII Shield area or at least
271    # below the executable).  If the prelink was performed in exec-shield
272    # mode, prelink could have no choice on how to randomize the single new
273    # unprelinked library address without wasting space in the first one/two
274    # memory areas.  In such case prelink could place $ARG repeatedly at the
275    # same place and we could have false prelink results on
276    # gdb.base/prelink.exp and others.  To prevent this from happening, we use
277    # the --no-exec-shield switch.  This may have some consequences in terms
278    # of security, but we do not care in our case.
279
280    set command "exec /usr/sbin/prelink -qNR --no-exec-shield $arg"
281
282    verbose -log "command is $command"
283    set result [catch $command output]
284    verbose -log "result is $result"
285    verbose -log "output is $output"
286    if {$result == 1 && [regexp {^(couldn't execute "/usr/sbin/prelink[^\r\n]*": no such file or directory\n?)*$} $output]} {
287	set test "$test (missing /usr/sbin/prelink)"
288
289	# We could not find prelink.  We could check whether $args is already
290	# prelinked but we don't, because:
291	#   - It is unlikely that someone uninstalls prelink after having
292	#     prelinked the system ld.so;
293	#   - We still cannot change its prelinked address.
294	# Therefore, we just skip the test.
295
296	xfail $test
297	return 0
298    }
299    if {$result == 1 && [regexp {DWARF [^\r\n]* unhandled} $output]} {
300	# Prelink didn't understand the version of dwarf present.
301	unsupported "$test (dwarf version unhandled)"
302	return 0
303    }
304    if {$result == 0 && $output == ""} {
305	pass $test
306	return 1
307    } elseif {$result == 1 \
308	      && [string match -nocase "*: Not enough room to add .dynamic entry" $output]} {
309	# Linker should have reserved some entries for prelink.
310	xfail $test
311	return 0
312    } else {
313	fail $test
314	return 0
315    }
316}
317