[PATCH v4] [PR gdb/27614] gdb-add-index fails on symlinks.

[PATCH v4] [PR gdb/27614] gdb-add-index fails on symlinks.

[Lancelot SIX via Gdb-patches]

Since V3:
	- Do net rely on GDB's maintenance commands to resolve
	symlinks, revert to using readlink while maximizing portability.

Since V2:
	- Use GDB to follow symlink instead of readlink. Unlike
	readlink, GDB is guaranteed to be available.

Since V1:
	- Replace '&>/dev/null' with '>/dev/null 2>&1'

--

PR 27614 shows that gdb-add-index fails to generate the index when its
argument is a symlink.

The following one liner illustrates the reported problem:

        $ echo 'int main(){}'|gcc -g -x c -;ln -s a.out symlink;gdb-add-index symlink
        gdb-add-index: No index was created for symlink
        gdb-add-index: [Was there no debuginfo? Was there already an index?]
        $ ls -l
        -rwxr-xr-x 1 25712 Mar 19 23:05 a.out*
        -rw------- 1  8277 Mar 19 23:05 a.out.gdb-index
        lrwxrwxrwx 1     5 Mar 19 23:05 symlink -> a.out*

GDB generates the .gdb-index file with a name that matches the name of
the actual program (a.out.gdb-index here), not the symlink that
references it.  The remaining of the script is looking for a file named
after the provided argument (would be 'symlink.gdb-index' in our
example).

gdb/ChangeLog:

	PR gdb/27614
	* contrib/gdb-add-index.sh: Fix when called with a symlink as an
	argument.

gdb/testsuite/ChangeLog:

	PR gdb/27614
	* gdb.dwarf2/gdb-add-index-symlink.exp: New test.
---
 gdb/contrib/gdb-add-index.sh                  | 28 +++++++++++
 .../gdb.dwarf2/gdb-add-index-symlink.exp      | 47 +++++++++++++++++++
 2 files changed, 75 insertions(+)
 create mode 100644 gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp

diff --git a/gdb/contrib/gdb-add-index.sh b/gdb/contrib/gdb-add-index.sh
index 2ac3fddbf26..734110caa3b 100755
--- a/gdb/contrib/gdb-add-index.sh
+++ b/gdb/contrib/gdb-add-index.sh
@@ -37,6 +37,34 @@ fi
 
 file="$1"
 
+if test -L "$file"; then
+    if ! command -v readlink >/dev/null 2>&1; then
+	echo "$myname: 'readlink' missing.  Failed to follow symlink $1." 1>&2
+	exit 1
+    fi
+
+    # Count number of links followed in order to detect loops.
+    count=0
+    while test -L "$file"; do
+	target=$(readlink "$file")
+
+	case "$target" in
+	    /*)
+		file="$target"
+		;;
+	    *)
+		file="$(dirname "$file")/$target"
+		;;
+	esac
+
+	count="$((count + 1))"
+	if test "$count" -gt 10; then
+	    echo "$myname: Detected loop while following link $file"
+	    exit 1
+	fi
+    done
+fi
+
 if test ! -r "$file"; then
     echo "$myname: unable to access: $file" 1>&2
     exit 1
diff --git a/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp b/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp
new file mode 100644
index 00000000000..eaeddec0250
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp
@@ -0,0 +1,47 @@
+# Copyright 2021 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2.
+if {![dwarf2_support]} {
+    return 0
+}
+
+standard_testfile main.c
+
+if { [prepare_for_testing "failed to prepare" "${testfile}" \
+	  [list ${srcfile}]] } {
+    return -1
+}
+
+set symlink [file dirname $binfile]/symlink
+
+if { ![file exists $symlink] } {
+    file link -symbolic $symlink $binfile
+}
+
+if { [ensure_gdb_index $symlink] == -1 } {
+    fail "Unable to call gdb-add-index with a symlink to a symfile"
+    return -1
+}
+
+# Ok, we have a copy of $binfile with an index.
+# Restart gdb and verify the index was used.
+
+clean_restart $symlink
+gdb_test "mt print objfiles ${testfile}" \
+    "(gdb_index|debug_names).*" \
+    "index used"
-- 
2.30.1

Re: [PATCH v4] [PR gdb/27614] gdb-add-index fails on symlinks.

[Lancelot SIX via Gdb-patches]

Hi,

Kindly pinging.

Lancelot.

On Mon, Mar 29, 2021 at 09:52:24PM +0100, Lancelot SIX wrote:
> Since V3:
> 	- Do net rely on GDB's maintenance commands to resolve
> 	symlinks, revert to using readlink while maximizing portability.
> 
> Since V2:
> 	- Use GDB to follow symlink instead of readlink. Unlike
> 	readlink, GDB is guaranteed to be available.
> 
> Since V1:
> 	- Replace '&>/dev/null' with '>/dev/null 2>&1'
> 
> --
> 
> PR 27614 shows that gdb-add-index fails to generate the index when its
> argument is a symlink.
> 
> The following one liner illustrates the reported problem:
> 
>         $ echo 'int main(){}'|gcc -g -x c -;ln -s a.out symlink;gdb-add-index symlink
>         gdb-add-index: No index was created for symlink
>         gdb-add-index: [Was there no debuginfo? Was there already an index?]
>         $ ls -l
>         -rwxr-xr-x 1 25712 Mar 19 23:05 a.out*
>         -rw------- 1  8277 Mar 19 23:05 a.out.gdb-index
>         lrwxrwxrwx 1     5 Mar 19 23:05 symlink -> a.out*
> 
> GDB generates the .gdb-index file with a name that matches the name of
> the actual program (a.out.gdb-index here), not the symlink that
> references it.  The remaining of the script is looking for a file named
> after the provided argument (would be 'symlink.gdb-index' in our
> example).
> 
> gdb/ChangeLog:
> 
> 	PR gdb/27614
> 	* contrib/gdb-add-index.sh: Fix when called with a symlink as an
> 	argument.
> 
> gdb/testsuite/ChangeLog:
> 
> 	PR gdb/27614
> 	* gdb.dwarf2/gdb-add-index-symlink.exp: New test.
> ---
>  gdb/contrib/gdb-add-index.sh                  | 28 +++++++++++
>  .../gdb.dwarf2/gdb-add-index-symlink.exp      | 47 +++++++++++++++++++
>  2 files changed, 75 insertions(+)
>  create mode 100644 gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp
> 
> diff --git a/gdb/contrib/gdb-add-index.sh b/gdb/contrib/gdb-add-index.sh
> index 2ac3fddbf26..734110caa3b 100755
> --- a/gdb/contrib/gdb-add-index.sh
> +++ b/gdb/contrib/gdb-add-index.sh
> @@ -37,6 +37,34 @@ fi
>  
>  file="$1"
>  
> +if test -L "$file"; then
> +    if ! command -v readlink >/dev/null 2>&1; then
> +	echo "$myname: 'readlink' missing.  Failed to follow symlink $1." 1>&2
> +	exit 1
> +    fi
> +
> +    # Count number of links followed in order to detect loops.
> +    count=0
> +    while test -L "$file"; do
> +	target=$(readlink "$file")
> +
> +	case "$target" in
> +	    /*)
> +		file="$target"
> +		;;
> +	    *)
> +		file="$(dirname "$file")/$target"
> +		;;
> +	esac
> +
> +	count="$((count + 1))"
> +	if test "$count" -gt 10; then
> +	    echo "$myname: Detected loop while following link $file"
> +	    exit 1
> +	fi
> +    done
> +fi
> +
>  if test ! -r "$file"; then
>      echo "$myname: unable to access: $file" 1>&2
>      exit 1
> diff --git a/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp b/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp
> new file mode 100644
> index 00000000000..eaeddec0250
> --- /dev/null
> +++ b/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp
> @@ -0,0 +1,47 @@
> +# Copyright 2021 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +load_lib dwarf.exp
> +
> +# This test can only be run on targets which support DWARF-2.
> +if {![dwarf2_support]} {
> +    return 0
> +}
> +
> +standard_testfile main.c
> +
> +if { [prepare_for_testing "failed to prepare" "${testfile}" \
> +	  [list ${srcfile}]] } {
> +    return -1
> +}
> +
> +set symlink [file dirname $binfile]/symlink
> +
> +if { ![file exists $symlink] } {
> +    file link -symbolic $symlink $binfile
> +}
> +
> +if { [ensure_gdb_index $symlink] == -1 } {
> +    fail "Unable to call gdb-add-index with a symlink to a symfile"
> +    return -1
> +}
> +
> +# Ok, we have a copy of $binfile with an index.
> +# Restart gdb and verify the index was used.
> +
> +clean_restart $symlink
> +gdb_test "mt print objfiles ${testfile}" \
> +    "(gdb_index|debug_names).*" \
> +    "index used"
> -- 
> 2.30.1
> 

-- 
Lancelot SIX

[PING] [PATCH v4] [PR gdb/27614] gdb-add-index fails on symlinks.

[Lancelot SIX via Gdb-patches]

Hi,

Kindly pinging,

Lancelot.

On Sat, Apr 17, 2021 at 06:16:23PM +0100, Lancelot SIX via Gdb-patches wrote:
> Hi,
> 
> Kindly pinging.
> 
> Lancelot.
> 
> On Mon, Mar 29, 2021 at 09:52:24PM +0100, Lancelot SIX wrote:
> > Since V3:
> > 	- Do net rely on GDB's maintenance commands to resolve
> > 	symlinks, revert to using readlink while maximizing portability.
> > 
> > Since V2:
> > 	- Use GDB to follow symlink instead of readlink. Unlike
> > 	readlink, GDB is guaranteed to be available.
> > 
> > Since V1:
> > 	- Replace '&>/dev/null' with '>/dev/null 2>&1'
> > 
> > --
> > 
> > PR 27614 shows that gdb-add-index fails to generate the index when its
> > argument is a symlink.
> > 
> > The following one liner illustrates the reported problem:
> > 
> >         $ echo 'int main(){}'|gcc -g -x c -;ln -s a.out symlink;gdb-add-index symlink
> >         gdb-add-index: No index was created for symlink
> >         gdb-add-index: [Was there no debuginfo? Was there already an index?]
> >         $ ls -l
> >         -rwxr-xr-x 1 25712 Mar 19 23:05 a.out*
> >         -rw------- 1  8277 Mar 19 23:05 a.out.gdb-index
> >         lrwxrwxrwx 1     5 Mar 19 23:05 symlink -> a.out*
> > 
> > GDB generates the .gdb-index file with a name that matches the name of
> > the actual program (a.out.gdb-index here), not the symlink that
> > references it.  The remaining of the script is looking for a file named
> > after the provided argument (would be 'symlink.gdb-index' in our
> > example).
> > 
> > gdb/ChangeLog:
> > 
> > 	PR gdb/27614
> > 	* contrib/gdb-add-index.sh: Fix when called with a symlink as an
> > 	argument.
> > 
> > gdb/testsuite/ChangeLog:
> > 
> > 	PR gdb/27614
> > 	* gdb.dwarf2/gdb-add-index-symlink.exp: New test.
> > ---
> >  gdb/contrib/gdb-add-index.sh                  | 28 +++++++++++
> >  .../gdb.dwarf2/gdb-add-index-symlink.exp      | 47 +++++++++++++++++++
> >  2 files changed, 75 insertions(+)
> >  create mode 100644 gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp
> > 
> > diff --git a/gdb/contrib/gdb-add-index.sh b/gdb/contrib/gdb-add-index.sh
> > index 2ac3fddbf26..734110caa3b 100755
> > --- a/gdb/contrib/gdb-add-index.sh
> > +++ b/gdb/contrib/gdb-add-index.sh
> > @@ -37,6 +37,34 @@ fi
> >  
> >  file="$1"
> >  
> > +if test -L "$file"; then
> > +    if ! command -v readlink >/dev/null 2>&1; then
> > +	echo "$myname: 'readlink' missing.  Failed to follow symlink $1." 1>&2
> > +	exit 1
> > +    fi
> > +
> > +    # Count number of links followed in order to detect loops.
> > +    count=0
> > +    while test -L "$file"; do
> > +	target=$(readlink "$file")
> > +
> > +	case "$target" in
> > +	    /*)
> > +		file="$target"
> > +		;;
> > +	    *)
> > +		file="$(dirname "$file")/$target"
> > +		;;
> > +	esac
> > +
> > +	count="$((count + 1))"
> > +	if test "$count" -gt 10; then
> > +	    echo "$myname: Detected loop while following link $file"
> > +	    exit 1
> > +	fi
> > +    done
> > +fi
> > +
> >  if test ! -r "$file"; then
> >      echo "$myname: unable to access: $file" 1>&2
> >      exit 1
> > diff --git a/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp b/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp
> > new file mode 100644
> > index 00000000000..eaeddec0250
> > --- /dev/null
> > +++ b/gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp
> > @@ -0,0 +1,47 @@
> > +# Copyright 2021 Free Software Foundation, Inc.
> > +
> > +# This program is free software; you can redistribute it and/or modify
> > +# it under the terms of the GNU General Public License as published by
> > +# the Free Software Foundation; either version 3 of the License, or
> > +# (at your option) any later version.
> > +#
> > +# This program is distributed in the hope that it will be useful,
> > +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > +# GNU General Public License for more details.
> > +#
> > +# You should have received a copy of the GNU General Public License
> > +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> > +
> > +load_lib dwarf.exp
> > +
> > +# This test can only be run on targets which support DWARF-2.
> > +if {![dwarf2_support]} {
> > +    return 0
> > +}
> > +
> > +standard_testfile main.c
> > +
> > +if { [prepare_for_testing "failed to prepare" "${testfile}" \
> > +	  [list ${srcfile}]] } {
> > +    return -1
> > +}
> > +
> > +set symlink [file dirname $binfile]/symlink
> > +
> > +if { ![file exists $symlink] } {
> > +    file link -symbolic $symlink $binfile
> > +}
> > +
> > +if { [ensure_gdb_index $symlink] == -1 } {
> > +    fail "Unable to call gdb-add-index with a symlink to a symfile"
> > +    return -1
> > +}
> > +
> > +# Ok, we have a copy of $binfile with an index.
> > +# Restart gdb and verify the index was used.
> > +
> > +clean_restart $symlink
> > +gdb_test "mt print objfiles ${testfile}" \
> > +    "(gdb_index|debug_names).*" \
> > +    "index used"
> > -- 
> > 2.30.1
> > 
> 
> -- 
> Lancelot SIX

-- 
Lancelot SIX

Re: [PATCH v4] [PR gdb/27614] gdb-add-index fails on symlinks.

[Simon Marchi via Gdb-patches]

On 2021-03-29 4:52 p.m., Lancelot SIX via Gdb-patches wrote:
> Since V3:
> 	- Do net rely on GDB's maintenance commands to resolve
> 	symlinks, revert to using readlink while maximizing portability.
> 
> Since V2:
> 	- Use GDB to follow symlink instead of readlink. Unlike
> 	readlink, GDB is guaranteed to be available.
> 
> Since V1:
> 	- Replace '&>/dev/null' with '>/dev/null 2>&1'
> 
> --
> 
> PR 27614 shows that gdb-add-index fails to generate the index when its
> argument is a symlink.
> 
> The following one liner illustrates the reported problem:
> 
>         $ echo 'int main(){}'|gcc -g -x c -;ln -s a.out symlink;gdb-add-index symlink
>         gdb-add-index: No index was created for symlink
>         gdb-add-index: [Was there no debuginfo? Was there already an index?]
>         $ ls -l
>         -rwxr-xr-x 1 25712 Mar 19 23:05 a.out*
>         -rw------- 1  8277 Mar 19 23:05 a.out.gdb-index
>         lrwxrwxrwx 1     5 Mar 19 23:05 symlink -> a.out*
> 
> GDB generates the .gdb-index file with a name that matches the name of
> the actual program (a.out.gdb-index here), not the symlink that
> references it.  The remaining of the script is looking for a file named
> after the provided argument (would be 'symlink.gdb-index' in our
> example).
> 
> gdb/ChangeLog:
> 
> 	PR gdb/27614
> 	* contrib/gdb-add-index.sh: Fix when called with a symlink as an
> 	argument.
> 
> gdb/testsuite/ChangeLog:
> 
> 	PR gdb/27614
> 	* gdb.dwarf2/gdb-add-index-symlink.exp: New test.

This is ok, thanks!

Simon

Re: [PATCH v4] [PR gdb/27614] gdb-add-index fails on symlinks.

[Lancelot SIX via Gdb-patches]

Hi,

Thanks.  This is pushed.

Lancelot.

On Sun, May 09, 2021 at 08:14:02PM -0400, Simon Marchi wrote:
> On 2021-03-29 4:52 p.m., Lancelot SIX via Gdb-patches wrote:
> > Since V3:
> > 	- Do net rely on GDB's maintenance commands to resolve
> > 	symlinks, revert to using readlink while maximizing portability.
> > 
> > Since V2:
> > 	- Use GDB to follow symlink instead of readlink. Unlike
> > 	readlink, GDB is guaranteed to be available.
> > 
> > Since V1:
> > 	- Replace '&>/dev/null' with '>/dev/null 2>&1'
> > 
> > --
> > 
> > PR 27614 shows that gdb-add-index fails to generate the index when its
> > argument is a symlink.
> > 
> > The following one liner illustrates the reported problem:
> > 
> >         $ echo 'int main(){}'|gcc -g -x c -;ln -s a.out symlink;gdb-add-index symlink
> >         gdb-add-index: No index was created for symlink
> >         gdb-add-index: [Was there no debuginfo? Was there already an index?]
> >         $ ls -l
> >         -rwxr-xr-x 1 25712 Mar 19 23:05 a.out*
> >         -rw------- 1  8277 Mar 19 23:05 a.out.gdb-index
> >         lrwxrwxrwx 1     5 Mar 19 23:05 symlink -> a.out*
> > 
> > GDB generates the .gdb-index file with a name that matches the name of
> > the actual program (a.out.gdb-index here), not the symlink that
> > references it.  The remaining of the script is looking for a file named
> > after the provided argument (would be 'symlink.gdb-index' in our
> > example).
> > 
> > gdb/ChangeLog:
> > 
> > 	PR gdb/27614
> > 	* contrib/gdb-add-index.sh: Fix when called with a symlink as an
> > 	argument.
> > 
> > gdb/testsuite/ChangeLog:
> > 
> > 	PR gdb/27614
> > 	* gdb.dwarf2/gdb-add-index-symlink.exp: New test.
> 
> This is ok, thanks!
> 
> Simon

-- 
Lancelot SIX