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 <siddhesh@sourceware.org>

diff --git a/NEWS b/NEWS
index 9bef1058b5ac4cda2c63a170c3e8127197ca63a2..88815bcad13432ad0128b293a01812ccf27a634e 100644 (file)
--- 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 3e32f254c51f937de3dc69c8aea5ec2eaa377eac..e4fa19ee4eef86091918783fcb944445589ba9d0 100644 (file)
--- 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 5f089038e12ee2f2559b9635a3ebf896cb6a927d..aa18256d86d7da8c209714f96ab2f3ded08615a6 100644 (file)
--- 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 042df725eb50510af6d0230ea181ddcf7a6dfc0e..3e7bd6852d7ff603c5ec0d81e8403584b483f337 100644 (file)
--- 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 (<LOCS>) {
+    # 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 (<locs>) {
            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 = <ADDR>;
+       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 = <ADDR>;
-           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 = <ADDR>;
-           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 = <ADDR>;
-           chomp $line;
-           close (ADDR);
-           if ($line ne '??:0') {
+       if ($binary ne "") {
+           my $line = &addr2line($binary, $addr);
+           if ($line) {
                $cache{$addr} = $line;
                return $cache{$addr};
            }