1# Copyright 2004-2021 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 17# The program sigstep.c creates a very simple backtrace containing one 18# signal handler and signal trampoline. A flag is set and then the 19# handler returns. This is repeated at infinitum. 20 21# This test runs the program up to the signal handler, and then 22# attempts to step/next out of the handler and back into main. 23 24if [target_info exists gdb,nosignals] { 25 verbose "Skipping sigstep.exp because of nosignals." 26 continue 27} 28 29 30standard_testfile 31 32if {[build_executable $testfile.exp $testfile $srcfile debug]} { 33 untested "failed to compile" 34 return -1 35} 36 37set clear_done [gdb_get_line_number {done = 0}] 38set infinite_loop [gdb_get_line_number {while (!done)}] 39set other_handler_location [gdb_get_line_number "other handler location"] 40 41# Restart GDB, set a display showing $PC, and run to main. 42 43proc restart {} { 44 global binfile 45 46 clean_restart $binfile 47 48 gdb_test "display/i \$pc" 49 50 runto_main 51} 52 53# Pass all the alarms straight through (but verbosely) 54# gdb_test "handle SIGALRM print pass nostop" 55# gdb_test "handle SIGVTALRM print pass nostop" 56# gdb_test "handle SIGPROF print pass nostop" 57 58# Run to the signal handler, validate the backtrace. 59 60proc validate_backtrace {} { 61 with_test_prefix "validate backtrace" { 62 restart 63 64 gdb_test "break handler" 65 gdb_test "continue" ".* handler .*" "continue to stepi handler" 66 gdb_test_sequence "bt" "backtrace for nexti" { 67 "\[\r\n\]+.0 \[^\r\n\]* handler " 68 "\[\r\n\]+.1 .signal handler called." 69 "\[\r\n\]+.2 \[^\r\n\]* main " 70 } 71 } 72} 73 74validate_backtrace 75 76# Goes to handler using ENTER_CMD, runs IN_HANDLER while in the signal 77# hander, and then steps out of the signal handler using EXIT_CMD. 78 79proc advance { enter_cmd in_handler_prefix in_handler exit_cmd } { 80 global gdb_prompt inferior_exited_re 81 global clear_done other_handler_location 82 83 set prefix "$enter_cmd to handler, $in_handler_prefix in handler, $exit_cmd from handler" 84 85 with_test_prefix $prefix { 86 restart 87 88 # Get us into the handler 89 if { $enter_cmd == "continue" } { 90 gdb_test "break handler" 91 } else { 92 gdb_test "handle SIGALRM print pass stop" 93 gdb_test "handle SIGVTALRM print pass stop" 94 gdb_test "continue" "Program received signal.*" "continue to signal" 95 } 96 gdb_test "$enter_cmd" ".*handler .*" "$enter_cmd to handler" 97 98 delete_breakpoints 99 100 uplevel 1 $in_handler 101 102 if { $exit_cmd == "continue" } { 103 gdb_test "break $clear_done" ".*" "break clear done" 104 } 105 106 set test "leave handler" 107 gdb_test_multiple "$exit_cmd" "${test}" { 108 -re "Could not insert single-step breakpoint.*$gdb_prompt $" { 109 setup_kfail gdb/8841 "sparc*-*-openbsd*" 110 fail "$test (could not insert single-step breakpoint)" 111 } 112 -re "Cannot insert breakpoint.*Cannot access memory.*$gdb_prompt $" { 113 setup_kfail gdb/8841 "nios2*-*-linux*" 114 fail "$test (could not insert single-step breakpoint)" 115 } 116 -re "done = 1;.*${gdb_prompt} $" { 117 send_gdb "$exit_cmd\n" 118 exp_continue -continue_timer 119 } 120 -re "\} .. handler .*${gdb_prompt} $" { 121 send_gdb "$exit_cmd\n" 122 exp_continue -continue_timer 123 } 124 -re "$inferior_exited_re normally.*${gdb_prompt} $" { 125 setup_kfail gdb/8744 powerpc-*-*bsd* 126 fail "$test (program exited)" 127 } 128 -re "(while ..done|done = 0).*${gdb_prompt} $" { 129 # After stepping out of a function /r signal-handler, GDB will 130 # advance the inferior until it is at the first instruction of 131 # a code-line. While typically things return to the middle of 132 # the "while..." (and hence GDB advances the inferior to the 133 # "return..." line) it is also possible for the return to land 134 # on the first instruction of "while...". Accept both cases. 135 pass "$test" 136 } 137 } 138 } 139} 140 141# Map of PREFIX => "things to do within the signal handler", for the 142# advance tests. 143 144set in_handler_map { 145 "nothing" { 146 } 147 "si+advance" { 148 # Advance to the second location in handler. 149 gdb_test "si" "handler.*" "si in handler" 150 151 set test "advance in handler" 152 gdb_test_multiple "advance $other_handler_location" $test { 153 -re "Program received signal SIGTRAP.*$gdb_prompt $" { 154 # On some versions of Linux (observed on 155 # 3.16.4-200.fc20.x86_64), using PTRACE_SINGLESTEP+sig 156 # to step into a signal handler, and then issuing 157 # another PTRACE_SINGLESTEP within the handler ends up 158 # with $eflags.TF mistakenly set, which results in 159 # subsequent PTRACE_CONTINUEs trapping after each 160 # insn. 161 if {$enter_cmd != "continue"} { 162 setup_xfail "i?86-*-linux*" gdb/17511 163 setup_xfail "x86_64-*-linux*" gdb/17511 164 } 165 fail "$test (spurious SIGTRAP)" 166 return 167 } 168 -re "other handler location.*$gdb_prompt $" { 169 pass $test 170 } 171 } 172 } 173} 174 175# Check that we can step/next/continue, etc. our way in and out of a 176# signal handler. Also test that we can step, and run to a breakpoint 177# within the handler. 178 179foreach enter_cmd { "stepi" "nexti" "step" "next" "continue" } { 180 if { $enter_cmd != "continue" && ![can_single_step_to_signal_handler] } { 181 continue 182 } 183 184 foreach exit_cmd { "step" "next" "continue" } { 185 foreach {in_handler_prefix in_handler} $in_handler_map { 186 advance $enter_cmd $in_handler_prefix $in_handler $exit_cmd 187 } 188 } 189} 190 191proc advancei { cmd } { 192 global gdb_prompt inferior_exited_re 193 194 with_test_prefix "$cmd from handleri" { 195 restart 196 197 # Get us into the handler. 198 gdb_test "break handler" 199 gdb_test "continue" ".* handler .*" "continue to handler" 200 201 set program_exited 0 202 set test "leave handler" 203 gdb_test_multiple "$cmd" "${test}" { 204 -re "Cannot insert breakpoint 0.*${gdb_prompt} $" { 205 # Some platforms use a special read-only page for signal 206 # trampolines. We can't set a breakpoint there, and we 207 # don't gracefully fall back to single-stepping. 208 setup_kfail gdb/8841 "i?86-*-linux*" 209 setup_kfail gdb/8841 "*-*-openbsd*" 210 setup_kfail gdb/8841 "nios2-*-linux*" 211 fail "$test (could not set breakpoint)" 212 return 213 } 214 -re "Could not insert single-step breakpoint.*$gdb_prompt $" { 215 setup_kfail gdb/8841 "sparc*-*-openbsd*" 216 fail "$test (could not insert single-step breakpoint)" 217 } 218 -re "Breakpoint \[0-9\]*, handler .*${gdb_prompt} $" { 219 fail "$test (hit breakpoint again)" 220 } 221 -re "done = 1;.*${gdb_prompt} $" { 222 send_gdb "$cmd\n" 223 exp_continue -continue_timer 224 } 225 -re "\} .. handler .*${gdb_prompt} $" { 226 send_gdb "$cmd\n" 227 exp_continue -continue_timer 228 } 229 -re "signal handler called.*${gdb_prompt} $" { 230 pass "$test" 231 } 232 -re "main .*${gdb_prompt} $" { 233 fail "$test (in main)" 234 } 235 -re "$inferior_exited_re normally.*${gdb_prompt} $" { 236 fail "$test (program exited)" 237 set program_exited 1 238 } 239 -re "Make handler return now.*y or n. $" { 240 send_gdb "y\n" 241 exp_continue -continue_timer 242 } 243 } 244 245 set test "leave signal trampoline" 246 gdb_test_multiple "$cmd" "${test}" { 247 -re "while .*${gdb_prompt} $" { 248 pass "$test (in main)" 249 } 250 -re "signal handler called.*${gdb_prompt} $" { 251 send_gdb "$cmd\n" 252 exp_continue -continue_timer 253 } 254 -re "return .*${gdb_prompt} $" { 255 fail "$test (stepped)" 256 } 257 -re "Make .*frame return now.*y or n. $" { 258 send_gdb "y\n" 259 exp_continue -continue_timer 260 } 261 -re "$inferior_exited_re normally.*${gdb_prompt} $" { 262 kfail gdb/8744 "$test (program exited)" 263 set program_exited 1 264 } 265 -re "The program is not being run.*${gdb_prompt} $" { 266 if { $program_exited } { 267 # Previously kfailed with an exit 268 pass "$test (the program is not being run)" 269 } else { 270 fail "$test (the program is not being run)" 271 } 272 } 273 } 274 } 275} 276 277# Check that we can step our way out of a signal handler, using 278# commands that first step out to the signal trampoline, and then out 279# to the mainline code. 280 281foreach cmd {"stepi" "nexti" "finish" "return"} { 282 advancei $cmd 283} 284 285# Check that we can step/next our way into / over a signal handler. 286 287# There are at least the following cases: breakpoint @pc VS breakpoint 288# in handler VS step / next / continue. 289 290 291# Try stepping when there's a signal pending, and a breakpoint at the 292# handler. Should step into the signal handler. 293 294proc skip_to_handler { cmd } { 295 global infinite_loop 296 297 with_test_prefix "$cmd to handler" { 298 restart 299 # Use the real-time itimer, as otherwize the process never gets 300 # enough time to expire the timer. 301 gdb_test_no_output "set itimer = itimer_real" 302 303 # Advance to the infinite loop. 304 gdb_test "advance $infinite_loop" ".*" "advance to infinite loop" 305 306 # Make the signal pending. 307 sleep 1 308 309 # Insert the handler breakpoint. 310 gdb_test "break handler" ".*" 311 312 # Step into the handler. 313 gdb_test "$cmd" " handler .*" "performing $cmd" 314 } 315} 316 317foreach cmd {"step" "next" "continue"} { 318 skip_to_handler $cmd 319} 320 321# Try stepping when there's a signal pending, and a breakpoint at the 322# handler's entry-point. Should step into the signal handler stopping 323# at the entry-point. 324 325# Some systems (e.x., GNU/Linux as of 2004-08-30), when delivering a 326# signal, resume the process at the first instruction of the signal 327# handler and not the first instruction of the signal trampoline. The 328# stack is constructed such that the signal handler still appears to 329# have been called by the trampoline code. This test checks that it 330# is possible to stop the inferior, even at that first instruction. 331 332proc skip_to_handler_entry { cmd } { 333 global infinite_loop 334 335 with_test_prefix "$cmd to handler entry" { 336 restart 337 # Use the real-time itimer, as otherwize the process never gets 338 # enough time to expire the timer. 339 gdb_test_no_output "set itimer = itimer_real" 340 341 # Advance to the infinite loop. 342 gdb_test "advance $infinite_loop" ".*" "advance to infinite loop" 343 344 # Make the signal pending. 345 sleep 1 346 347 # Insert / remove the handler breakpoint. 348 gdb_test "break *handler" ".*" "break handler" 349 gdb_test "$cmd" " handler .*" "performing $cmd" 350 } 351} 352 353foreach cmd {"stepi" "nexti" "step" "next" "continue"} { 354 skip_to_handler_entry $cmd 355} 356 357# Get the address of where a single-step should land. 358 359proc get_next_pc {test} { 360 global gdb_prompt 361 global hex 362 363 set next "" 364 gdb_test_multiple "x/2i \$pc" $test { 365 -re "$hex .*:\[^\r\n\]+\r\n\[ \]+($hex).*\.\r\n$gdb_prompt $" { 366 set next $expect_out(1,string) 367 pass $test 368 } 369 } 370 371 return $next 372} 373 374# Test that the command skipped over the handler. 375 376proc test_skip_handler {cmd} { 377 if {$cmd == "stepi" || $cmd == "nexti"} { 378 set next_pc [get_next_pc "get next PC"] 379 gdb_test "$cmd" "dummy = 0.*" "performing $cmd" 380 gdb_test "p /x \$pc" " = $next_pc" "advanced" 381 } else { 382 gdb_test "$cmd" "done = 0.*" "performing $cmd" 383 } 384} 385 386# Try stepping when there's a signal pending but no breakpoints. 387# Should skip the handler advancing to the next line. 388 389proc skip_over_handler { cmd } { 390 global infinite_loop 391 global clear_done 392 393 with_test_prefix "$cmd over handler" { 394 restart 395 # Use the real-time itimer, as otherwize the process never gets 396 # enough time to expire the timer. 397 gdb_test_no_output "set itimer = itimer_real" 398 399 gdb_test "break $clear_done" ".*" "break clear done" 400 401 # Advance to the infinite loop. 402 gdb_test "advance $infinite_loop" ".*" "advance to infinite loop" 403 404 # Make the signal pending. 405 sleep 1 406 407 test_skip_handler $cmd 408 } 409} 410 411foreach cmd {"stepi" "nexti" "step" "next" "continue"} { 412 skip_over_handler $cmd 413} 414 415# Try stepping when there's a signal pending, a pre-existing 416# breakpoint at the current instruction, and a breakpoint in the 417# handler. Should advance to the signal handler. DISPLACED indicates 418# whether to try with or without displaced stepping (to exercise the 419# different techniques of stepping over the breakpoint at the current 420# instruction). 421 422proc breakpoint_to_handler { displaced cmd } { 423 global infinite_loop 424 425 with_test_prefix "displaced=$displaced: $cmd on breakpoint, to handler" { 426 restart 427 428 gdb_test_no_output "set displaced-stepping $displaced" 429 430 # Use the real-time itimer, as otherwize the process never gets 431 # enough time to expire the timer. 432 gdb_test_no_output "set itimer = itimer_real" 433 434 gdb_test "break $infinite_loop" ".*" "break infinite loop" 435 gdb_test "break handler" ".*" 436 437 # Continue to the infinite loop. 438 gdb_test "continue" "while ..done.*" "continue to infinite loop" 439 440 # Make the signal pending. 441 sleep 1 442 443 gdb_test "$cmd" " handler .*" "performing $cmd" 444 445 # Make sure we the displaced stepping scratch pad isn't in the 446 # backtrace. 447 gdb_test_sequence "bt" "backtrace" { 448 "\[\r\n\]+.0 \[^\r\n\]* handler " 449 "\[\r\n\]+.1 .signal handler called." 450 "\[\r\n\]+.2 \[^\r\n\]* main " 451 } 452 } 453} 454 455foreach displaced {"off" "on"} { 456 foreach cmd {"step" "next" "continue"} { 457 breakpoint_to_handler $displaced $cmd 458 } 459} 460 461# Try stepping when there's a signal pending, and a breakpoint at the 462# handler's entry instruction and a breakpoint at the current 463# instruction. Should step into the signal handler and breakpoint at 464# that entry instruction. 465 466# Some systems (e.x., GNU/Linux as of 2004-08-30), when delivering a 467# signal, resume the process at the first instruction of the signal 468# handler and not the first instruction of the signal trampoline. The 469# stack is constructed such that the signal handler still appears to 470# have been called by the trampoline code. This test checks that it 471# is possible to stop the inferior, even at that first instruction. 472 473# DISPLACED indicates whether to try with or without displaced 474# stepping (to exercise the different techniques of stepping over the 475# breakpoint at the current instruction). 476proc breakpoint_to_handler_entry { displaced cmd } { 477 global infinite_loop 478 479 with_test_prefix "displaced=$displaced: $cmd on breakpoint, to handler entry" { 480 restart 481 482 gdb_test_no_output "set displaced-stepping $displaced" 483 484 # Use the real-time itimer, as otherwize the process never gets 485 # enough time to expire the timer. 486 gdb_test_no_output "set itimer = itimer_real" 487 488 gdb_test "break $infinite_loop" ".*" "break infinite loop" 489 gdb_test "break *handler" ".*" "break handler" 490 491 # Continue to the infinite loop. 492 gdb_test "continue" "while ..done.*" "continue to infinite loop" 493 494 # Make the signal pending. 495 sleep 1 496 497 gdb_test "$cmd" " handler .*" "performing $cmd" 498 499 # Make sure we the displaced stepping scratch pad isn't in the 500 # backtrace. 501 gdb_test_sequence "bt" "backtrace" { 502 "\[\r\n\]+.0 \[^\r\n\]* handler " 503 "\[\r\n\]+.1 .signal handler called." 504 "\[\r\n\]+.2 \[^\r\n\]* main " 505 } 506 } 507} 508 509foreach displaced {"off" "on"} { 510 foreach cmd {"step" "next" "continue"} { 511 breakpoint_to_handler_entry $displaced $cmd 512 } 513} 514 515# Try stepping when there's a signal pending, and a pre-existing 516# breakpoint at the current instruction, and no breakpoint in the 517# handler. Should advance to the next line/instruction. DISPLACED 518# indicates whether to try with or without displaced stepping (to 519# exercise the different techniques of stepping over the breakpoint at 520# the current instruction). If SW_WATCH is true, set a software 521# watchpoint, which exercises stepping the breakpoint instruction 522# while delivering a signal at the same time. If NO_HANDLER, arrange 523# for the signal's handler be SIG_IGN, thus when the software 524# watchpoint is also set, testing stepping a breakpoint instruction 525# and immediately triggering the breakpoint (exercises 526# adjust_pc_after_break logic). 527 528proc breakpoint_over_handler { displaced cmd with_sw_watch no_handler } { 529 global infinite_loop 530 global clear_done 531 532 set prefix "$cmd on breakpoint, skip handler" 533 if { $with_sw_watch } { 534 append prefix ", with sw-watchpoint" 535 } 536 if { $no_handler } { 537 append prefix ", no handler" 538 } 539 540 with_test_prefix "displaced=$displaced: $prefix" { 541 restart 542 543 gdb_test_no_output "set displaced-stepping $displaced" 544 545 # Use the real-time itimer, as otherwize the process never gets 546 # enough time to expire the timer. 547 gdb_test_no_output "set itimer = itimer_real" 548 549 if {$no_handler} { 550 gdb_test "print no_handler = 1" " = 1" \ 551 "set no_handler" 552 } 553 554 gdb_test "break $infinite_loop" ".*" "break infinite loop" 555 556 gdb_test "break $clear_done" ".*" "break clear done" 557 558 # Continue to the infinite loop 559 gdb_test "continue" "while ..done.*" "continue to infinite loop" 560 561 # Make the signal pending 562 sleep 1 563 564 if { $with_sw_watch } { 565 # A watchpoint on a convenience variable is always a 566 # software watchpoint. 567 gdb_test "watch \$convenience" "Watchpoint .*: \\\$convenience" 568 } 569 570 if {$no_handler} { 571 # With no handler, we need to set the global ourselves 572 # manually. 573 gdb_test "print done = 1" " = 1" "set done" 574 } 575 576 test_skip_handler $cmd 577 } 578} 579 580foreach displaced {"off" "on"} { 581 foreach cmd {"stepi" "nexti" "step" "next" "continue"} { 582 foreach with_sw_watch {0 1} { 583 foreach no_handler {0 1} { 584 breakpoint_over_handler $displaced $cmd $with_sw_watch $no_handler 585 } 586 } 587 } 588} 589