Make "info proc cmdline" show args on GNU/Linux
Commit Message
Currently "info proc cmdline" on GNU/Linux does not show the full command
line, but only argument 0. And even a warning is shown if there are more.
This was discussed in 2014 already:
https://sourceware.org/ml/gdb-patches/2014-04/msg00212.html
Follow the advice there and avoid target_fileio_read_stralloc. Instead,
use target_fileio_read_alloc to read the whole command line and then
replace NUL characters by spaces. Also add an appropriate test case.
Note that gdbserver already handles this correctly.
gdb/ChangeLog:
* linux-tdep.c (linux_info_proc): For "info proc cmdline", print
command line args instead of emitting a warning.
gdb/testsuite/ChangeLog:
* gdb.base/info-proc.exp: Add test for "info proc cmdline".
---
gdb/linux-tdep.c | 20 ++++++++++++++++----
gdb/testsuite/gdb.base/info-proc.exp | 13 +++++++++++++
2 files changed, 29 insertions(+), 4 deletions(-)
Comments
On 2018-03-21 09:15 AM, Andreas Arnez wrote:
> Currently "info proc cmdline" on GNU/Linux does not show the full command
> line, but only argument 0. And even a warning is shown if there are more.
> This was discussed in 2014 already:
>
> https://sourceware.org/ml/gdb-patches/2014-04/msg00212.html
>
> Follow the advice there and avoid target_fileio_read_stralloc. Instead,
> use target_fileio_read_alloc to read the whole command line and then
> replace NUL characters by spaces. Also add an appropriate test case.
> Note that gdbserver already handles this correctly.
Hi Andreas,
This LGTM with two minor nits:
> gdb/ChangeLog:
>
> * linux-tdep.c (linux_info_proc): For "info proc cmdline", print
> command line args instead of emitting a warning.
>
> gdb/testsuite/ChangeLog:
>
> * gdb.base/info-proc.exp: Add test for "info proc cmdline".
> ---
> gdb/linux-tdep.c | 20 ++++++++++++++++----
> gdb/testsuite/gdb.base/info-proc.exp | 13 +++++++++++++
> 2 files changed, 29 insertions(+), 4 deletions(-)
>
> diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
> index b4b87dd..0ac78c2 100644
> --- a/gdb/linux-tdep.c
> +++ b/gdb/linux-tdep.c
> @@ -754,10 +754,22 @@ linux_info_proc (struct gdbarch *gdbarch, const char *args,
> if (cmdline_f)
> {
> xsnprintf (filename, sizeof filename, "/proc/%ld/cmdline", pid);
> - gdb::unique_xmalloc_ptr<char> cmdline
> - = target_fileio_read_stralloc (NULL, filename);
> - if (cmdline)
> - printf_filtered ("cmdline = '%s'\n", cmdline.get ());
> + gdb_byte *buffer;
> + ssize_t len = target_fileio_read_alloc (NULL, filename, &buffer);
> +
> + if (len > 0)
> + {
> + gdb::unique_xmalloc_ptr<char> cmdline ((char *) buffer);
> + ssize_t pos;
> +
> + for (pos = 0; pos < len - 1; pos++)
> + {
> + if (buffer[pos] == '\0')
> + buffer[pos] = ' ';
> + }
> + buffer[len - 1] = '\0';
> + printf_filtered ("cmdline = '%s'\n", buffer);
> + }
> else
> warning (_("unable to open /proc file '%s'"), filename);
> }
> diff --git a/gdb/testsuite/gdb.base/info-proc.exp b/gdb/testsuite/gdb.base/info-proc.exp
> index 72355bf..eadcb15 100644
> --- a/gdb/testsuite/gdb.base/info-proc.exp
> +++ b/gdb/testsuite/gdb.base/info-proc.exp
> @@ -38,6 +38,16 @@ gdb_test_multiple "info proc" "info proc without a process" {
> }
> }
>
> +# Set command line arguments to be verified later with "info proc
> +# cmdline". However, if we're using a stub, then "set args" would not
> +# have any effect, so then just skip this.
> +
> +set cmdline ""
> +if { ! [target_info exists use_gdb_stub] } {
The use_gdb_stub proc from lib/gdb.exp should be used instead (its comment
explains why).
> + set cmdline "-i foo bar -o baz 1234"
> + gdb_test_no_output "set args $cmdline" "set args"
> +}
> +
> if { ! [ runto_main ] } then {
> untested "could not run to main"
> return -1
> @@ -50,6 +60,9 @@ gdb_test "info proc mapping" \
> "info proc mapping"
>
> if {[istarget "*-*-linux*"]} {
> + if { $cmdline != "" } {
> + gdb_test "info proc cmdline" "cmdline = \'.* $cmdline\'"
The backslashes are unnecessary.
Simon
On Wed, Mar 21 2018, Simon Marchi wrote:
> On 2018-03-21 09:15 AM, Andreas Arnez wrote:
>> Currently "info proc cmdline" on GNU/Linux does not show the full command
>> line, but only argument 0. And even a warning is shown if there are more.
>> This was discussed in 2014 already:
>>
>> https://sourceware.org/ml/gdb-patches/2014-04/msg00212.html
>>
>> Follow the advice there and avoid target_fileio_read_stralloc. Instead,
>> use target_fileio_read_alloc to read the whole command line and then
>> replace NUL characters by spaces. Also add an appropriate test case.
>> Note that gdbserver already handles this correctly.
>
> Hi Andreas,
>
> This LGTM with two minor nits:
>
[...]
>>
>> +# Set command line arguments to be verified later with "info proc
>> +# cmdline". However, if we're using a stub, then "set args" would not
>> +# have any effect, so then just skip this.
>> +
>> +set cmdline ""
>> +if { ! [target_info exists use_gdb_stub] } {
>
> The use_gdb_stub proc from lib/gdb.exp should be used instead (its comment
> explains why).
Ah, OK. There are still some occurrences of "target_info exists
use_gdb_stub" in the test suite. Should these be replaced as well?
>
>> + set cmdline "-i foo bar -o baz 1234"
>> + gdb_test_no_output "set args $cmdline" "set args"
>> +}
>> +
>> if { ! [ runto_main ] } then {
>> untested "could not run to main"
>> return -1
>> @@ -50,6 +60,9 @@ gdb_test "info proc mapping" \
>> "info proc mapping"
>>
>> if {[istarget "*-*-linux*"]} {
>> + if { $cmdline != "" } {
>> + gdb_test "info proc cmdline" "cmdline = \'.* $cmdline\'"
>
> The backslashes are unnecessary.
Right.
Thanks for your review. Pushed with these fixes.
--
Andreas
On 2018-03-22 05:04, Andreas Arnez wrote:
>>>
>>> +# Set command line arguments to be verified later with "info proc
>>> +# cmdline". However, if we're using a stub, then "set args" would
>>> not
>>> +# have any effect, so then just skip this.
>>> +
>>> +set cmdline ""
>>> +if { ! [target_info exists use_gdb_stub] } {
>>
>> The use_gdb_stub proc from lib/gdb.exp should be used instead (its
>> comment
>> explains why).
>
> Ah, OK. There are still some occurrences of "target_info exists
> use_gdb_stub" in the test suite. Should these be replaced as well?
Yes, they probably should.
>>
>>> + set cmdline "-i foo bar -o baz 1234"
>>> + gdb_test_no_output "set args $cmdline" "set args"
>>> +}
>>> +
>>> if { ! [ runto_main ] } then {
>>> untested "could not run to main"
>>> return -1
>>> @@ -50,6 +60,9 @@ gdb_test "info proc mapping" \
>>> "info proc mapping"
>>>
>>> if {[istarget "*-*-linux*"]} {
>>> + if { $cmdline != "" } {
>>> + gdb_test "info proc cmdline" "cmdline = \'.* $cmdline\'"
>>
>> The backslashes are unnecessary.
>
> Right.
>
> Thanks for your review. Pushed with these fixes.
Thanks!
Simon
@@ -754,10 +754,22 @@ linux_info_proc (struct gdbarch *gdbarch, const char *args,
if (cmdline_f)
{
xsnprintf (filename, sizeof filename, "/proc/%ld/cmdline", pid);
- gdb::unique_xmalloc_ptr<char> cmdline
- = target_fileio_read_stralloc (NULL, filename);
- if (cmdline)
- printf_filtered ("cmdline = '%s'\n", cmdline.get ());
+ gdb_byte *buffer;
+ ssize_t len = target_fileio_read_alloc (NULL, filename, &buffer);
+
+ if (len > 0)
+ {
+ gdb::unique_xmalloc_ptr<char> cmdline ((char *) buffer);
+ ssize_t pos;
+
+ for (pos = 0; pos < len - 1; pos++)
+ {
+ if (buffer[pos] == '\0')
+ buffer[pos] = ' ';
+ }
+ buffer[len - 1] = '\0';
+ printf_filtered ("cmdline = '%s'\n", buffer);
+ }
else
warning (_("unable to open /proc file '%s'"), filename);
}
@@ -38,6 +38,16 @@ gdb_test_multiple "info proc" "info proc without a process" {
}
}
+# Set command line arguments to be verified later with "info proc
+# cmdline". However, if we're using a stub, then "set args" would not
+# have any effect, so then just skip this.
+
+set cmdline ""
+if { ! [target_info exists use_gdb_stub] } {
+ set cmdline "-i foo bar -o baz 1234"
+ gdb_test_no_output "set args $cmdline" "set args"
+}
+
if { ! [ runto_main ] } then {
untested "could not run to main"
return -1
@@ -50,6 +60,9 @@ gdb_test "info proc mapping" \
"info proc mapping"
if {[istarget "*-*-linux*"]} {
+ if { $cmdline != "" } {
+ gdb_test "info proc cmdline" "cmdline = \'.* $cmdline\'"
+ }
set gcorefile [standard_output_file $testfile.gcore]
if {[gdb_gcore_cmd $gcorefile "save a core file"]} {
clean_restart $binfile