From d7703d3176d225d5743b21811d888619eba39e82 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Fri, 21 Jan 2022 10:20:50 -0300 Subject: [PATCH] malloc: Remove LD_TRACE_PRELINKING usage from mtrace The fix for BZ#22716 replacde LD_TRACE_LOADED_OBJECTS with LD_TRACE_PRELINKING so mtrace could record executable address position. To provide the same information, LD_TRACE_LOADED_OBJECTS is extended where a value or '2' also prints the executable address as well. It avoid adding another loader environment variable to be used solely for mtrace. The vDSO will be printed as a default library (with '=>' pointing the same name), which is ok since both mtrace and ldd already handles it. The mtrace script is changed to also parse the new format. To correctly support PIE and non-PIE executables, both the default mtrace address and the one calculated as used (it fixes mtrace for non-PIE exectuable as for BZ#22716 for PIE). Checked on x86_64-linux-gnu. Reviewed-by: Siddhesh Poyarekar --- NEWS | 4 ++++ elf/dl-main.h | 3 +++ elf/rtld.c | 22 +++++++++++++--------- malloc/mtrace.pl | 55 +++++++++++++++++++++++++++++++------------------------ 4 files changed, 51 insertions(+), 33 deletions(-) diff --git a/NEWS b/NEWS index 9bef105..88815bc 100644 --- a/NEWS +++ b/NEWS @@ -193,6 +193,10 @@ Deprecated and removed features, and other changes affecting compatibility: removal of the LD_TRACE_PRELINKING, and LD_USE_LOAD_BIAS, environment variables and their functionality in the dynamic loader. +* The LD_TRACE_PRELINKING environment variable has been removed. Similar + functionality to obtain the program mapping address can be achieved by + using LD_TRACE_LOADED_OBJECTS to value of 2. + Changes to build and runtime requirements: * The audit module interface version LAV_CURRENT is increased to enable diff --git a/elf/dl-main.h b/elf/dl-main.h index 3e32f25..e4fa19e 100644 --- a/elf/dl-main.h +++ b/elf/dl-main.h @@ -94,6 +94,9 @@ struct dl_main_state enum rtld_mode mode; + /* True if program should be also printed for rtld_mode_trace. */ + bool mode_trace_program; + /* True if any of the debugging options is enabled. */ bool any_debug; diff --git a/elf/rtld.c b/elf/rtld.c index 5f08903..aa18256 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -2104,18 +2104,18 @@ dl_main (const ElfW(Phdr) *phdr, _dl_printf ("\tstatically linked\n"); else { - for (l = main_map->l_next; l; l = l->l_next) + for (l = state.mode_trace_program ? main_map : main_map->l_next; + l; l = l->l_next) { if (l->l_faked) /* The library was not found. */ - _dl_printf ("\t%s => not found\n", l->l_libname->name); - else if (strcmp (l->l_libname->name, l->l_name) == 0) - _dl_printf ("\t%s (0x%0*Zx)\n", l->l_libname->name, - (int) sizeof l->l_map_start * 2, - (size_t) l->l_map_start); + _dl_printf ("\t%s => not found\n", l->l_libname->name); else - _dl_printf ("\t%s => %s (0x%0*Zx)\n", l->l_libname->name, - l->l_name, (int) sizeof l->l_map_start * 2, + _dl_printf ("\t%s => %s (0x%0*Zx)\n", + DSO_FILENAME (l->l_libname->name), + DSO_FILENAME (l->l_name), + (int) sizeof l->l_map_start * 2, (size_t) l->l_map_start); + } } if (__glibc_unlikely (state.mode != rtld_mode_trace)) @@ -2676,7 +2676,11 @@ process_envvars (struct dl_main_state *state) case 20: /* The mode of the dynamic linker can be set. */ if (memcmp (envline, "TRACE_LOADED_OBJECTS", 20) == 0) - state->mode = rtld_mode_trace; + { + state->mode = rtld_mode_trace; + state->mode_trace_program + = _dl_strtoul (&envline[21], NULL) > 1; + } break; /* We might have some extra environment variable to handle. This diff --git a/malloc/mtrace.pl b/malloc/mtrace.pl index 042df72..3e7bd68 100644 --- a/malloc/mtrace.pl +++ b/malloc/mtrace.pl @@ -74,15 +74,14 @@ if ($#ARGV == 0) { } else { $prog = "./$binary"; } - # Set the environment variable LD_TRACE_PRELINKING to an empty string so - # that we trigger tracing but do not match with the executable or any of - # its dependencies. - if (open (LOCS, "env LD_TRACE_PRELINKING= $prog |")) { - while () { + # Set the environment variable LD_TRACE_LOADED_OBJECTS to 2 so the + # executable is also printed. + if (open (locs, "env LD_TRACE_LOADED_OBJECTS=2 $prog |")) { + while () { chop; - if (/^.*=> (.*) \((0x[0123456789abcdef]*), (0x[0123456789abcdef]*).*/) { + if (/^.*=> (.*) .(0x[0123456789abcdef]*).$/) { $locs{$1} = $2; - $rel{$1} = hex($2) - hex($3); + $rel{$1} = hex($2); } } close (LOCS); @@ -91,6 +90,18 @@ if ($#ARGV == 0) { die "Wrong number of arguments, run $progname --help for help."; } +sub addr2line { + my $addr = pop(@_); + my $prog = pop(@_); + if (open (ADDR, "addr2line -e $prog $addr|")) { + my $line = ; + chomp $line; + close (ADDR); + if ($line ne '??:0') { + return $line + } + } +} sub location { my $str = pop(@_); return $str if ($str eq ""); @@ -98,11 +109,9 @@ sub location { my $addr = $1; my $fct = $2; return $cache{$addr} if (exists $cache{$addr}); - if ($binary ne "" && open (ADDR, "addr2line -e $binary $addr|")) { - my $line = ; - chomp $line; - close (ADDR); - if ($line ne '??:0') { + if ($binary ne "") { + my $line = &addr2line($binary, $addr); + if ($line) { $cache{$addr} = $line; return $cache{$addr}; } @@ -114,24 +123,22 @@ sub location { my $searchaddr; return $cache{$addr} if (exists $cache{$addr}); $searchaddr = sprintf "%#x", hex($addr) + $rel{$prog}; - if ($binary ne "" && open (ADDR, "addr2line -e $prog $searchaddr|")) { - my $line = ; - chomp $line; - close (ADDR); - if ($line ne '??:0') { - $cache{$addr} = $line; - return $cache{$addr}; + if ($binary ne "") { + for my $address ($searchaddr, $addr) { + my $line = &addr2line($prog, $address); + if ($line) { + $cache{$addr} = $line; + return $cache{$addr}; + } } } $cache{$addr} = $str = $addr; } elsif ($str =~ /^.*[[](0x[^]]*)]$/) { my $addr = $1; return $cache{$addr} if (exists $cache{$addr}); - if ($binary ne "" && open (ADDR, "addr2line -e $binary $addr|")) { - my $line = ; - chomp $line; - close (ADDR); - if ($line ne '??:0') { + if ($binary ne "") { + my $line = &addr2line($binary, $addr); + if ($line) { $cache{$addr} = $line; return $cache{$addr}; } -- 2.7.4