Re: [Crash-utility] [PATCH] Allows to change the error output direction

Hi Dave, There was a missed corner case that it doesn't work if scroll is on. The new patch is passed both scroll on and off. First, this doesn't work as you've advertised: > > crash> set stderr /dev/null > stderr: /dev/null > crash> sym 555 > sym: invalid address: 555 > crash> The new patch applied you had mentioned. I was also unhappy with name 'fp'. > > Secondly, could you change the name of the "stderr" variable? It's > kind of confusing, especially since the crash internals specifically > avoid using stderr. Perhaps use "error" instead? And then with respect > to the 3 possible options, "fp" is confusing and somewhat meaningless > to a user -- let's use "redirect", since that's what you're describing. > > Internally, please clarify/rename the "pc->stderr" and "pc->stderr_path" > member > names to be "pc->error_fp" and "pc->error_path". And in > dump_program_context(), > display both members explicitly as such, not the way you are displaying > the stderr FILE pointer as the stderr_path string: > > + fprintf(fp, " stderr: %s\n", pc->stderr_path); > > In the case of 'redirect', we have to update file pointer on the fly as it can have different value from the default stdout or current fp. > At the beginning of __error(), you've got this: > > + if (!strcmp(pc->stderr_path, "fp")) > + pc->stderr = fp; > + > > I don't understand that. What's going on there? > > Applied STREQ() for those locations. Kind regards, Daniel Kwon > And lastly, just for my own sanity, in all the places where you're > using strcmp() and !strcmp(), can you please just use STREQ() instead? > > Thanks, > Dave > > > > > > ----- Original Message ----- > > I shouldn't use that message in the previous email. Yes, I am writing > > a command that does extra actions while doing 'dis' which gives you > > some extra information to make it easy to understand the code. As a > > part of it, it is trying to find symbols for any given values. > > > > Anyway, here I put another example that just does calling 'sym' > > command in exec_crash_command(). You can try it once load 'mpykdump' > > shared object. > > > > > ----------------------------------------------------------------------------------- > > $ pwd > > /root/Work > > $ cat test_cmd.py > > from pykdump.API import * > > > > def test_cmd(): > > try: > > sym = exec_crash_command("sym 0x123") > > print("{%s}" % sym) > > except: > > pass > > > > > > if ( __name__ == '__main__'): > > test_cmd() > > > > $ ./crash > > ... > > crash> extend /root/.crash.d/mpykdump.so > > /root/.crash.d/mpykdump.so: shared object loaded > > > > crash> set stderr default > > stderr: default > > crash> epython /root/Work/test_cmd.py > > sym: invalid address: 0x123 > > {sym: invalid address: 0x123 > > } > > > > ** Execution took 0.00s (real) 0.00s (CPU) > > crash> set stderr fp > > stderr: fp > > crash> epython /root/Work/test_cmd.py > > {sym: invalid address: 0x123 > > } > > > > ** Execution took 0.00s (real) 0.00s (CPU) > > crash> set stderr /tmp/output > > stderr: /tmp/output > > crash> epython /root/Work/test_cmd.py > > crash> !cat /tmp/output > > sym: invalid address: 0x123 > > > ----------------------------------------------------------------------------------- > > > > Yes, in the above by using 'fp', we can redirect the error message > > into the same exec_crash_command() and prevent showing any messages on > > console. By doing that, we can have a full control for the messages. > > If we want to seperate error messages from the beginning, but not > > making duplicate, we could use file path instead. > > > > PS. I am attaching a new patch that has a small change as there was a > > memory leak when file open is failed. > > > > Regards, > > Daniel Kwon > > > > On Sun, Jun 30, 2019 at 1:42 AM Dave Anderson <anderson(a)redhat.com&gt; > wrote: > > > > > > > > > > > > ----- Original Message ----- > > > > I am writing an extension based on 'mpykdump' and calling > > > > 'exec_crash_command()' to find symbol details as shown below. > > > > > > > > --- > > > > def find_symbol(str): > > > > try: > > > > sym = exec_crash_command("sym %s" % str) > > > > if sym.startswith("sym:") != True: > > > > return " <" + "".join(sym.split()[2:]) + ">" > > > > except: > > > > pass > > > > > > > > return "" > > > > --- > > > > > > > > In the below example, I am trying to interpret address > > > > '0xffff92a3fba0f100' by calling 'sym' crash command, but can't handle > > > > the situation where the symbol doesn't exist. > > > > > > > > --- > > > > ... > > > > 0xffffffff92858b75 <do_sys_poll+741>: callq 0xffffffff92986f80 > > > > <__x86_indirect_thunk_rdx> > > > > sym: invalid address: 0xffff92a3fba0f100 > > > > 0xffffffff92858b7a <do_sys_poll+746>: mov 0x50(%rsp),%rcx > > > > ;0xffff92a3fba0f100 > > > > ... > > > > --- > > > > > > > > By using 'fp', I can redirect the error into the > > > > 'exec_crash_command()' result which I can use to identify the reason > > > > if there's error and can avoid showing unnecessary error on console. > > > > > > If you'll allow me to continue beating a dead horse... > > > > > > I've never used mpykdump before, and it's confusing because you are > showing > > > disassembly > > > output, with a "sym" command error message appearing in the middle. > Are > > > you calling > > > excec_crash_command() while you are parsing disassembly output from > within > > > some other > > > mypkdump execution stream? > > > > > > Anyway, are you saying that -- with the current behavior -- when you > > > redirect the exec_crash_command() > > > function, that the sym error messages do *not* go to the redirected > file or > > > pipe stream? > > > > > > It sounds like you're saying that your proposed "fp" setting would > simply > > > not display the extra > > > "unnecessary" error message on the console. > > > > > > Dave > > > > > > > > > > > > > > Regards, > > > > Daniel > > > > > > > > Kind regards, > > > > > > > > Daniel Kwon, RHCA > > > > > > > > Principle Software Maintenance Engineer, CEE > > > > > > > > Red Hat APAC > > > > > > > > > > > > > > > > On Fri, Jun 28, 2019 at 11:41 PM Dave Anderson <anderson(a)redhat.com&gt; > > > > wrote: > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > Hi Dave, > > > > > > > > > > > > Yes, that is violating the default behaviour. I recheck how it > should > > > > > > be handled and made the below rules. > > > > > > > > > > > > - 'default' : Working just like the 'crash' before this 'stderr' > > > > > > implementation. > > > > > > - 'fp' : Only goes into one destination. It can be console in > normal > > > > > > command, but will go into target file if redirection or pipe is > used. > > > > > > > > > > I still don't understand why you want to bother with this "fp" > option? > > > > > What's the problem you're trying to address? > > > > > > > > > > Dave > > > > > > > > > > > > > > > > - '<path>' : It will go into the specified file only and no > console > > > > > > output. > > > > > > > > > > > > Below is the test I have done for the test. Hope this behaviour > is > > > > > > reasonable. > > > > > > > > > > > > --------------------------- > > > > > > ## default: standard error handling behaviour. > > > > > > > > > > > > normal command: error prints on console > > > > > > > > > > > > crash> set stderr default > > > > > > stderr: default > > > > > > > > > > > > crash> sym 0x123 > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > redirect: goes into both console and redirected file. > > > > > > > > > > > > crash> sym 0x123 > /tmp/output > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > crash> !cat /tmp/output > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > > > > > > > pipe: goes into both console and piped direction. > > > > > > > > > > > > crash> sym 0x123 | cat > > > > > > sym: invalid address: 0x123 > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > crash> sym 0x123 | cat > /tmp/output > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > crash> !cat /tmp/output > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ## fp: Only to the one target such as stdout, pipe, or redirected > > > > > > file > > > > > > > > > > > > normal command: error prints on console > > > > > > > > > > > > crash> set stderr fp > > > > > > stderr: fp > > > > > > > > > > > > crash> sym 0x123 > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > redirect: goes into redirected file only. > > > > > > > > > > > > crash> sym 0x123 > /tmp/output > > > > > > crash> !cat /tmp/output > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > > > > > > > pipe: goes into piped direction only. > > > > > > > > > > > > crash> sym 0x123 | cat > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > crash> sym 0x123 | cat > /tmp/output > > > > > > > > > > > > crash> !cat /tmp/output > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > > > > > > > > > > > > > ## <file path>: Only to the specified file. > > > > > > > > > > > > normal command: error goes into the specified file only. > > > > > > > > > > > > crash> set stderr /tmp/stderr > > > > > > stderr: /tmp/stderr > > > > > > crash> sym 0x123 > > > > > > crash> !cat /tmp/stderr > > > > > > sym: invalid address: 0x123 > > > > > > > > > > > > redirect: error goes into the specified file only. > > > > > > > > > > > > crash> sym 0x124 > /tmp/output > > > > > > crash> !cat /tmp/output > > > > > > crash> !cat /tmp/stderr > > > > > > sym: invalid address: 0x123 > > > > > > sym: invalid address: 0x124 > > > > > > > > > > > > pipe: error goes into the specified file only. > > > > > > > > > > > > crash> sym 0x125 | cat > > > > > > crash> sym 0x126 | cat > /tmp/output > > > > > > crash> !cat /tmp/output > > > > > > crash> !cat /tmp/stderr > > > > > > sym: invalid address: 0x123 > > > > > > sym: invalid address: 0x124 > > > > > > sym: invalid address: 0x125 > > > > > > sym: invalid address: 0x126 > > > > > > --------------------------- > > > > > > > > > > > > Regards, > > > > > > Daniel Kwon > > > > > > > > > > > > Kind regards, > > > > > > > > > > > > Daniel Kwon, RHCA > > > > > > > > > > > > Principle Software Maintenance Engineer, CEE > > > > > > > > > > > > Red Hat APAC > > > > > > > > > > > > > > > > > > > > > > > > On Fri, Jun 28, 2019 at 5:27 AM Dave Anderson < > anderson(a)redhat.com&gt; > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > > > Hi Dave, > > > > > > > > > > > > > > > > It looks like __error() function has an extra output which > can > > > > > > > > cause > > > > > > > > of > > > > > > > > confusion. I rewrote the code to cover that as well as the > > > > > > > > changes > > > > > > > > you > > > > > > > > had > > > > > > > > asked. Please let me know how it goes. > > > > > > > > > > > > > > Hi Daniel, > > > > > > > > > > > > > > Upon initial testing, I note that your patch changes the > default > > > > > > > behavior, > > > > > > > which is unacceptable. > > > > > > > > > > > > > > By default, the idea is to get all error() messages out so that > > > > > > > they > > > > > > > are > > > > > > > seen by the user regardless of how the command's output may be > > > > > > > piped or > > > > > > > redirected. So if a command's output is redirected to a file > or > > > > > > > pipe, > > > > > > > the error message goes both to the console as well as being > > > > > > > intermingled > > > > > > > in the pipe/file command output. > > > > > > > > > > > > > > Taking your simple example, by default, command output and > error > > > > > > > messages > > > > > > > are piped (behind the scenes) to /usr/bin/less: > > > > > > > > > > > > > > crash> sym 0x523 > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> > > > > > > > > > > > > > > If the default piping is turned off, command output and error > > > > > > > messages > > > > > > > go to stdout: > > > > > > > > > > > > > > crash> set scroll off > > > > > > > scroll: off (/usr/bin/less) > > > > > > > crash> sym 0x523 > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> > > > > > > > > > > > > > > However, if the command is redirected to a file, any command > output > > > > > > > and > > > > > > > error > > > > > > > messages go to the file, but error messages also go to the > console: > > > > > > > > > > > > > > crash> sym 0x523 > /tmp/output > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> !cat /tmp/output > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> > > > > > > > > > > > > > > Similarly, if the command is piped to a command, command > output and > > > > > > > error > > > > > > > messages > > > > > > > go to the pipe, and error messages also go to the console: > > > > > > > > > > > > > > crash> sym 0x523 | cat > > > > > > > sym: invalid address: 0x523 > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> > > > > > > > > > > > > > > So with your patch applied, and the new stderr variable set to > the > > > > > > > default > > > > > > > of "stdout": > > > > > > > > > > > > > > crash> set stderr > > > > > > > stderr: stdout > > > > > > > crash> > > > > > > > > > > > > > > Let's run the same set of commands as above: > > > > > > > > > > > > > > crash> sym 0x523 > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> set scroll off > > > > > > > scroll: off (/usr/bin/less) > > > > > > > crash> sym 0x523 > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> > > > > > > > > > > > > > > Same behavior as always. However, if a command is redirected > to a > > > > > > > file, > > > > > > > the error message only goes to the console, but it is not sent > to > > > > > > > the > > > > > > > output file: > > > > > > > > > > > > > > crash> sym 0x523 > /tmp/output > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> !cat /tmp/output > > > > > > > crash> > > > > > > > > > > > > > > Similarly, when piped to a command, the error message is only > going > > > > > > > to > > > > > > > one of the destinations: > > > > > > > > > > > > > > crash> sym 0x523 | cat > > > > > > > sym: invalid address: 0x523 > > > > > > > crash> > > > > > > > > > > > > > > So there's no way I'm going to change behavior from what it has > > > > > > > been forever. > > > > > > > > > > > > > > While I didn't test your alternative settings, it's not > entirely > > > > > > > clear > > > > > > > what you're trying to accomplish. Seemingly it would make > sense to > > > > > > > have > > > > > > > a binary setting for the new "stderr": > > > > > > > > > > > > > > (1) the current default behavior, or > > > > > > > (2) a setting allowing you to redirect all error() messages > to a > > > > > > > designated file. > > > > > > > > > > > > > > Option (2) would *not* send them to the console *or* > intermingle > > > > > > > them > > > > > > > with command output. But that's just me... > > > > > > > > > > > > > > Also, here's a minor compiler complaint: > > > > > > > > > > > > > > $ make warn > > > > > > > ... > > > > > > > cc -c -g -DX86_64 -DLZO -DSNAPPY -DGDB_7_6 main.c -Wall -O2 > > > > > > > -Wstrict-prototypes -Wmissing-prototypes -fstack-protector > > > > > > > -Wformat-security > > > > > > > main.c: In function ‘setup_environment’: > > > > > > > main.c:1088:9: warning: implicit declaration of function > > > > > > > ‘set_stderr’ > > > > > > > [-Wimplicit-function-declaration] > > > > > > > set_stderr("stdout"); > > > > > > > ^ > > > > > > > cc -c -g -DX86_64 -DLZO -DSNAPPY -DGDB_7_6 tools.c -Wall -O2 > > > > > > > -Wstrict-prototypes -Wmissing-prototypes -fstack-protector > > > > > > > -Wformat-security > > > > > > > tools.c:42:1: warning: no previous prototype for ‘set_stderr’ > > > > > > > [-Wmissing-prototypes] > > > > > > > set_stderr(char *target) > > > > > > > ^ > > > > > > > ... > > > > > > > > > > > > > > Thanks, > > > > > > > Dave > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Kind regards, > > > > > > > > Daniel Kwon > > > > > > > > > > > > > > > > On Tue, Jun 25, 2019 at 2:06 AM Dave Anderson > > > > > > > > <anderson(a)redhat.com&gt; > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > > > > > Hi Dave, > > > > > > > > > > > > > > > > > > > > Here I attach as a file for the patch. Thanks. > > > > > > > > > > > > > > > > > > > > Kind regards, > > > > > > > > > > Daniel > > > > > > > > > > > > > > > > > > Hi Daniel, > > > > > > > > > > > > > > > > > > As I mentioned before, the concept seems reasonable, which > I > > > > > > > > > thought > > > > > > > > > was to allow a user to prevent error() messages from being > > > > > > > > > intermingled > > > > > > > > > with command output by redirecting them somewhere else. > But > > > > > > > > > that's > > > > > > > > > apparently not the case, as a few simple examples show > > > > > > > > > otherwise. > > > > > > > > > > > > > > > > > > Here's the default setting, and a sample command > generating an > > > > > > > > > error: > > > > > > > > > > > > > > > > > > crash> set -v > > > > > > > > > scroll: on (/usr/bin/less) > > > > > > > > > radix: 10 (decimal) > > > > > > > > > refresh: on > > > > > > > > > print_max: 256 > > > > > > > > > print_array: off > > > > > > > > > console: (not assigned) > > > > > > > > > debug: 0 > > > > > > > > > core: off > > > > > > > > > hash: on > > > > > > > > > silent: off > > > > > > > > > edit: vi > > > > > > > > > namelist: > > > > > > > > > > /usr/lib/debug/lib/modules/3.10.0-957.21.2.el7.x86_64/vmlinux > > > > > > > > > dumpfile: (null) > > > > > > > > > unwind: off > > > > > > > > > zero_excluded: off > > > > > > > > > null-stop: off > > > > > > > > > gdb: off > > > > > > > > > scope: 0 (not set) > > > > > > > > > offline: show > > > > > > > > > redzone: on > > > > > > > > > stderr: stdout > > > > > > > > > crash> bt 33333 > > > > > > > > > bt: invalid task or pid value: 33333 > > > > > > > > > crash> > > > > > > > > > > > > > > > > > > Here I set stderr to /dev/null, which sets the new > pc->stderr, > > > > > > > > > but the behavior is still the same: > > > > > > > > > > > > > > > > > > crash> set stderr /dev/null > > > > > > > > > stderr: /dev/null > > > > > > > > > crash> set -v > > > > > > > > > scroll: on (/usr/bin/less) > > > > > > > > > radix: 10 (decimal) > > > > > > > > > refresh: on > > > > > > > > > print_max: 256 > > > > > > > > > print_array: off > > > > > > > > > console: (not assigned) > > > > > > > > > debug: 0 > > > > > > > > > core: off > > > > > > > > > hash: on > > > > > > > > > silent: off > > > > > > > > > edit: vi > > > > > > > > > namelist: > > > > > > > > > > /usr/lib/debug/lib/modules/3.10.0-957.21.2.el7.x86_64/vmlinux > > > > > > > > > dumpfile: (null) > > > > > > > > > unwind: off > > > > > > > > > zero_excluded: off > > > > > > > > > null-stop: off > > > > > > > > > gdb: off > > > > > > > > > scope: 0 (not set) > > > > > > > > > offline: show > > > > > > > > > redzone: on > > > > > > > > > stderr: /dev/null > > > > > > > > > crash> bt 33333 > > > > > > > > > bt: invalid task or pid value: 33333 > > > > > > > > > crash> > > > > > > > > > > > > > > > > > > Or if I set it to a file, the same thing happens: > > > > > > > > > > > > > > > > > > crash> set stderr /tmp/junk > > > > > > > > > stderr: /tmp/junk > > > > > > > > > crash> set -v > > > > > > > > > scroll: on (/usr/bin/less) > > > > > > > > > radix: 10 (decimal) > > > > > > > > > refresh: on > > > > > > > > > print_max: 256 > > > > > > > > > print_array: off > > > > > > > > > console: (not assigned) > > > > > > > > > debug: 0 > > > > > > > > > core: off > > > > > > > > > hash: on > > > > > > > > > silent: off > > > > > > > > > edit: vi > > > > > > > > > namelist: > > > > > > > > > > /usr/lib/debug/lib/modules/3.10.0-957.21.2.el7.x86_64/vmlinux > > > > > > > > > dumpfile: (null) > > > > > > > > > unwind: off > > > > > > > > > zero_excluded: off > > > > > > > > > null-stop: off > > > > > > > > > gdb: off > > > > > > > > > scope: 0 (not set) > > > > > > > > > offline: show > > > > > > > > > redzone: on > > > > > > > > > stderr: /tmp/junk > > > > > > > > > crash> bt 33333 > > > > > > > > > bt: invalid task or pid value: 33333 > > > > > > > > > crash> > > > > > > > > > > > > > > > > > > With your patch applied, the help page indicates: > > > > > > > > > > > > > > > > > > stderr stdout | fp | <path> set the direction of error > put. > > > > > > > > > 'stdout' > > > > > > > > > always > > > > > > > > > print on console. 'fp' > follows > > > > > > > > > the > > > > > > > > > redirection > > > > > > > > > or pipe command. '<path>' > can be > > > > > > > > > any > > > > > > > > > file > > > > > > > > > path > > > > > > > > > in the filesystem which can > save > > > > > > > > > the > > > > > > > > > output > > > > > > > > > > > > > > > > > > Is states that "<path>" can be any file path in the > filesystem > > > > > > > > > which > > > > > > > > > can > > > > > > > > > save > > > > > > > > > the output. But even I redirect a command, it still > doesn't > > > > > > > > > seem > > > > > > > > > to do > > > > > > > > > what > > > > > > > > > it states: > > > > > > > > > > > > > > > > > > crash> set stderr /dev/null > > > > > > > > > stderr: /dev/null > > > > > > > > > crash> bt 33333 > /tmp/junk > > > > > > > > > crash> !cat /tmp/junk > > > > > > > > > bt: invalid task or pid value: 33333 > > > > > > > > > crash> > > > > > > > > > > > > > > > > > > Or if I pipe it: > > > > > > > > > > > > > > > > > > crash> bt 33333 | cat > > > > > > > > > bt: invalid task or pid value: 33333 > > > > > > > > > crash> > > > > > > > > > > > > > > > > > > What am I missing? > > > > > > > > > > > > > > > > > > And also, a couple more things... > > > > > > > > > > > > > > > > > > Please make pc->stderr_path a pointer: > > > > > > > > > > > > > > > > > > --- a/defs.h > > > > > > > > > +++ b/defs.h > > > > > > > > > @@ -553,6 +553,8 @@ struct program_context { > > > > > > > > > ulong scope; /* optional text > > > > > > > > > context > > > > > > > > > address > > > > > > > > > */ > > > > > > > > > ulong nr_hash_queues; /* hash queue > head > > > > > > > > > count > > > > > > > > > */ > > > > > > > > > char *(*read_vmcoreinfo)(const char *); > > > > > > > > > + FILE *stderr; /* error() > message > > > > > > > > > direction > > > > > > > > > */ > > > > > > > > > + char stderr_path[PATH_MAX]; /* stderr path > > > > > > > > > information > > > > > > > > > */ > > > > > > > > > }; > > > > > > > > > > > > > > > > > > Since it's typically going to contain a handful of bytes, > it's > > > > > > > > > kind > > > > > > > > > of > > > > > > > > > wasteful > > > > > > > > > to use PATH_MAX (4096). Just use malloc/free to get a > buffer > > > > > > > > > of > > > > > > > > > the > > > > > > > > > correct > > > > > > > > > length. > > > > > > > > > > > > > > > > > > And please display pc->stderr and pc->stderr_path to > > > > > > > > > dump_program_context() > > > > > > > > > for use by "help -p". > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > Dave > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Sat, Jun 22, 2019 at 5:24 AM Dave Anderson < > > > > > > > > > > anderson(a)redhat.com > > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Hi Daniel, > > > > > > > > > > > > > > > > > > > > The idea seems reasonable, but the patch below is > malformed: > > > > > > > > > > > > > > > > > > > > $ patch -p1 < error.patch > > > > > > > > > > checking file defs.h > > > > > > > > > > Hunk #1 FAILED at 553. > > > > > > > > > > 1 out of 1 hunk FAILED > > > > > > > > > > checking file help.c > > > > > > > > > > patch: **** malformed patch at line 52: displayed by", > > > > > > > > > > > > > > > > > > > > $ > > > > > > > > > > > > > > > > > > > > You can see that there are a quite a few unintended line > > > > > > > > > > wraps > > > > > > > > > > in the patch below. > > > > > > > > > > > > > > > > > > > > Can you make the patch a discrete attachment to your > email? > > > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > Dave > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > > > > > > Currently, the error() is always printing the output > to the > > > > > > > > > > > console > > > > > > > > > > > through 'stdout'. This does not follow redirection > which is > > > > > > > > > > > good > > > > > > > > > > > when > > > > > > > > > > > you want to know error while redirecting commands > output to > > > > > > > > > > > a > > > > > > > > > > > file. > > > > > > > > > > > However, there are situations that you want to hide > error > > > > > > > > > > > messages > > > > > > > > > > > or > > > > > > > > > > > redirect it into somewhere else. > > > > > > > > > > > > > > > > > > > > > > Using 'set stderr' command, it can be changed to three > > > > > > > > > > > different > > > > > > > > > > > destination - fixed 'stdout', following redirection > (fp), > > > > > > > > > > > or a > > > > > > > > > > > custom > > > > > > > > > > > file path. > > > > > > > > > > > > > > > > > > > > > > crash> set stderr > > > > > > > > > > > stderr: stdout > > > > > > > > > > > crash> sym 0x523 > /dev/null > > > > > > > > > > > sym: invalid address: 0x523 > > > > > > > > > > > crash> set stderr fp > > > > > > > > > > > stderr: fp > > > > > > > > > > > crash> sym 0x523 > /dev/null > > > > > > > > > > > crash> set stderr /tmp/err.log > > > > > > > > > > > stderr: /tmp/err.log > > > > > > > > > > > crash> sym 0x523 > /dev/null > > > > > > > > > > > crash> set stderr stdout > > > > > > > > > > > stderr: stdout > > > > > > > > > > > crash> sym 0x523 > /dev/null > > > > > > > > > > > sym: invalid address: 0x523 > > > > > > > > > > > --- > > > > > > > > > > > defs.h | 2 ++ > > > > > > > > > > > help.c | 5 +++++ > > > > > > > > > > > main.c | 2 ++ > > > > > > > > > > > tools.c | 55 > > > > > > > > > > > ++++++++++++++++++++++++++++++++++++++++++++++++++++--- > > > > > > > > > > > 4 files changed, 61 insertions(+), 3 deletions(-) > > > > > > > > > > > > > > > > > > > > > > diff --git a/defs.h b/defs.h > > > > > > > > > > > index ccffe58..57850c6 100644 > > > > > > > > > > > --- a/defs.h > > > > > > > > > > > +++ b/defs.h > > > > > > > > > > > @@ -553,6 +553,8 @@ struct program_context { > > > > > > > > > > > ulong scope; /* optional text context address */ > > > > > > > > > > > ulong nr_hash_queues; /* hash queue head count */ > > > > > > > > > > > char *(*read_vmcoreinfo)(const char *); > > > > > > > > > > > + FILE *stderr; /* error() message direction */ > > > > > > > > > > > + char stderr_path[PATH_MAX]; /* stderr path > information */ > > > > > > > > > > > }; > > > > > > > > > > > > > > > > > > > > > > #define READMEM pc->readmem > > > > > > > > > > > diff --git a/help.c b/help.c > > > > > > > > > > > index 581e616..ddc8e86 100644 > > > > > > > > > > > --- a/help.c > > > > > > > > > > > +++ b/help.c > > > > > > > > > > > @@ -1093,6 +1093,10 @@ char *help_set[] = { > > > > > > > > > > > " redzone on | off if on, CONFIG_SLUB object addresses > > > > > > > > > > > displayed by", > > > > > > > > > > > " the kmem command will point to the > > > > > > > > > > > SLAB_RED_ZONE", > > > > > > > > > > > " padding inserted at the beginning of > > > > > > > > > > > the object.", > > > > > > > > > > > +" stderr stdout | fp | <path> set the direction of > error > > > > > > > > > > > put. > > > > > > > > > > > 'stdout' always", > > > > > > > > > > > +" print on console. 'fp' follows the > > > > > > > > > > > redirection", > > > > > > > > > > > +" or pipe command. '<path>' can be any > > > > > > > > > > > file path", > > > > > > > > > > > +" in the filesystem which can save the > > > > > > > > > > > output", > > > > > > > > > > > " ", > > > > > > > > > > > " Internal variables may be set in four manners:\n", > > > > > > > > > > > " 1. entering the set command in $HOME/.%src.", > > > > > > > > > > > @@ -1144,6 +1148,7 @@ char *help_set[] = { > > > > > > > > > > > " scope: (not set)", > > > > > > > > > > > " offline: show", > > > > > > > > > > > " redzone: on", > > > > > > > > > > > +" stderr: stdout", > > > > > > > > > > > " ", > > > > > > > > > > > " Show the current context:\n", > > > > > > > > > > > " %s> set", > > > > > > > > > > > diff --git a/main.c b/main.c > > > > > > > > > > > index 83ccd31..68bdec4 100644 > > > > > > > > > > > --- a/main.c > > > > > > > > > > > +++ b/main.c > > > > > > > > > > > @@ -1085,6 +1085,8 @@ setup_environment(int argc, char > > > > > > > > > > > **argv) > > > > > > > > > > > * to pipes or output files. > > > > > > > > > > > */ > > > > > > > > > > > fp = stdout; > > > > > > > > > > > + pc->stderr = stdout; > > > > > > > > > > > + strcpy(pc->stderr_path, "stdout"); > > > > > > > > > > > > > > > > > > > > > > /* > > > > > > > > > > > * Start populating the program_context structure. It's > used > > > > > > > > > > > so > > > > > > > > > > > diff --git a/tools.c b/tools.c > > > > > > > > > > > index 2d95c3a..840d07c 100644 > > > > > > > > > > > --- a/tools.c > > > > > > > > > > > +++ b/tools.c > > > > > > > > > > > @@ -58,6 +58,9 @@ __error(int type, char *fmt, ...) > > > > > > > > > > > void *retaddr[NUMBER_STACKFRAMES] = { 0 }; > > > > > > > > > > > va_list ap; > > > > > > > > > > > > > > > > > > > > > > + if (!strcmp(pc->stderr_path, "fp")) > > > > > > > > > > > + pc->stderr = fp; > > > > > > > > > > > + > > > > > > > > > > > if (CRASHDEBUG(1) || (pc->flags & DROP_CORE)) { > > > > > > > > > > > SAVE_RETURN_ADDRESS(retaddr); > > > > > > > > > > > console("error() trace: %lx => %lx => %lx => %lx\n", > > > > > > > > > > > @@ -69,7 +72,7 @@ __error(int type, char *fmt, ...) > > > > > > > > > > > va_end(ap); > > > > > > > > > > > > > > > > > > > > > > if (!fmt && FATAL_ERROR(type)) { > > > > > > > > > > > - fprintf(stdout, "\n"); > > > > > > > > > > > + fprintf(pc->stderr, "\n"); > > > > > > > > > > > clean_exit(1); > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > @@ -95,14 +98,14 @@ __error(int type, char *fmt, ...) > > > > > > > > > > > buf); > > > > > > > > > > > fflush(pc->stdpipe); > > > > > > > > > > > } else { > > > > > > > > > > > - fprintf(stdout, "%s%s%s %s%s", > > > > > > > > > > > + fprintf(pc->stderr, "%s%s%s %s%s", > > > > > > > > > > > new_line || end_of_line ? "\n" : "", > > > > > > > > > > > type == WARNING ? "WARNING" : > > > > > > > > > > > type == NOTE ? "NOTE" : > > > > > > > > > > > type == CONT ? spacebuf : pc->curcmd, > > > > > > > > > > > type == CONT ? " " : ":", > > > > > > > > > > > buf, end_of_line ? "\n" : ""); > > > > > > > > > > > - fflush(stdout); > > > > > > > > > > > + fflush(pc->stderr); > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > if ((fp != stdout) && (fp != pc->stdpipe) && (fp != > > > > > > > > > > > pc->tmpfile)) { > > > > > > > > > > > @@ -2483,6 +2486,51 @@ cmd_set(void) > > > > > > > > > > > } > > > > > > > > > > > return; > > > > > > > > > > > > > > > > > > > > > > + } else if (STREQ(args[optind], "stderr")) { > > > > > > > > > > > + if (args[optind+1]) { > > > > > > > > > > > + FILE *tmp_fp = NULL; > > > > > > > > > > > + char tmp_path[PATH_MAX]; > > > > > > > > > > > + > > > > > > > > > > > + optind++; > > > > > > > > > > > + if (STREQ(args[optind], "stdout")) { > > > > > > > > > > > + tmp_fp = stdout; > > > > > > > > > > > + strcpy(tmp_path, "stdout"); > > > > > > > > > > > + } else if (STREQ(args[optind], "fp")) { > > > > > > > > > > > + tmp_fp = fp; > > > > > > > > > > > + strcpy(tmp_path, "fp"); > > > > > > > > > > > + } else { > > > > > > > > > > > + if (strlen(args[optind]) >= > > > > > > > > > > > PATH_MAX) { > > > > > > > > > > > + error(INFO, "path > > > > > > > > > > > length %d is too long. (max=%d)\n", > > > > > > > > > > > + > > > > > > > > > > > strlen(args[optind]), PATH_MAX); > > > > > > > > > > > + return; > > > > > > > > > > > + } > > > > > > > > > > > + tmp_fp = fopen(args[optind], "a"); > > > > > > > > > > > + if (tmp_fp != NULL) { > > > > > > > > > > > + strcpy(tmp_path, > > > > > > > > > > > args[optind]); > > > > > > > > > > > + } else { > > > > > > > > > > > + error(INFO, "invalid > > > > > > > > > > > path: %s\n", > > > > > > > > > > > + args[optind]); > > > > > > > > > > > + return; > > > > > > > > > > > + } > > > > > > > > > > > + > > > > > > > > > > > + } > > > > > > > > > > > + > > > > > > > > > > > + if (strcmp(pc->stderr_path, tmp_path)) { > > > > > > > > > > > + if (strcmp(pc->stderr_path, > > > > > > > > > > > "stdout") > > > > > > > > > > > + && strcmp(pc->stderr_path, > > > > > > > > > > > "fp")) { > > > > > > > > > > > + fclose(pc->stderr); > > > > > > > > > > > + } > > > > > > > > > > > + pc->stderr = tmp_fp; > > > > > > > > > > > + strcpy(pc->stderr_path, tmp_path); > > > > > > > > > > > + } > > > > > > > > > > > + } > > > > > > > > > > > + > > > > > > > > > > > + if (runtime) { > > > > > > > > > > > + fprintf(fp, "stderr: %s\n", > > > > > > > > > > > + pc->stderr_path); > > > > > > > > > > > + } > > > > > > > > > > > + return; > > > > > > > > > > > + > > > > > > > > > > > } else if (XEN_HYPER_MODE()) { > > > > > > > > > > > error(FATAL, "invalid argument for the Xen > hypervisor\n"); > > > > > > > > > > > } else if (pc->flags & MINIMAL_MODE) { > > > > > > > > > > > @@ -2590,6 +2638,7 @@ show_options(void) > > > > > > > > > > > fprintf(fp, "(not set)\n"); > > > > > > > > > > > fprintf(fp, " offline: %s\n", pc->flags2 & > OFFLINE_HIDE ? > > > > > > > > > > > "hide" : "show"); > > > > > > > > > > > fprintf(fp, " redzone: %s\n", pc->flags2 & REDZONE ? > "on" : > > > > > > > > > > > "off"); > > > > > > > > > > > + fprintf(fp, " stderr: %s\n", pc->stderr_path); > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > > 1.8.3.1 > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > > Crash-utility mailing list > > > > > > > > > > > Crash-utility(a)redhat.com > > > > > > > > > > > https://www.redhat.com/mailman/listinfo/crash-utility > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > Crash-utility mailing list > > > > > > > > > > Crash-utility(a)redhat.com > > > > > > > > > > https://www.redhat.com/mailman/listinfo/crash-utility > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > Crash-utility mailing list > > > > > > > > > > Crash-utility(a)redhat.com > > > > > > > > > > https://www.redhat.com/mailman/listinfo/crash-utility > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >