[PATCH 0/3] -Y, --decode-pids option for printing command names for PIDs

[Masatake YAMATO]

In some applications like qemu-kvm, threads change their
command names to indicate their roles in the application.
Users can access the command name via /proc/$pid/comm.
The command name can be a great hit to understand the application
behavior.

This pull request introduces -Y option that enables printing command
names where PIDs appear.

For example (without -Y option):

  # src/strace -e poll,ioctl -f -p "$(pidof qemu-system-x86_64)"
  [pid 254329] ioctl(18, KVM_RUN <unfinished ...>
  [pid 254332] ioctl(21, KVM_RUN <unfinished ...>
  [pid 254331] ioctl(20, KVM_RUN <unfinished ...>
  [pid 254330] ioctl(19, KVM_RUN <unfinished ...>
  [pid 254309] poll([{fd=9, events=POLLOUT}], 1, 0) = 1 ...
  [pid 254309] poll([{fd=9, events=POLLOUT}], 1, 0) = 1 ...

(with -Y option):

  # src/strace -e poll,ioctl -Y -f -p "$(pidof qemu-system-x86_64)"
  [pid 254329<CPU 0/KVM>] ioctl(18, KVM_RUN <unfinished ...>
  [pid 254332<CPU 3/KVM>] ioctl(21, KVM_RUN <unfinished ...>
  [pid 254331<CPU 2/KVM>] ioctl(20, KVM_RUN <unfinished ...>
  [pid 254330<CPU 1/KVM>] ioctl(19, KVM_RUN <unfinished ...>
  [pid 254309<qemu-system-x86>] poll([{fd=9, events=POLLOUT}], 1, 0) = 1 ...
  [pid 254309<qemu-system-x86>] poll([{fd=9, events=POLLOUT}], 1, 0) = 1 ...

This change considers only PIDs in the prefixes of trace lines.
Printing command names for PIDs in arguments and return values is
future work.

Masatake YAMATO (3):
  Load /proc/$pid/comm into tcb
  Implement -Y option for printing command names for PIDs
  tests: add a test for -Y option

 NEWS                              |  1 +
 doc/strace.1.in                   |  5 ++
 src/defs.h                        |  5 ++
 src/filter_seccomp.c              |  3 +-
 src/linux/32/syscallent.h         |  6 +--
 src/linux/64/syscallent.h         |  6 +--
 src/linux/alpha/syscallent.h      |  6 +--
 src/linux/arm/syscallent.h        |  6 +--
 src/linux/avr32/syscallent.h      |  6 +--
 src/linux/bfin/syscallent.h       |  6 +--
 src/linux/hppa/syscallent.h       |  6 +--
 src/linux/i386/syscallent.h       |  6 +--
 src/linux/ia64/syscallent.h       |  6 +--
 src/linux/m68k/syscallent.h       |  6 +--
 src/linux/microblaze/syscallent.h |  6 +--
 src/linux/mips/syscallent-n32.h   |  6 +--
 src/linux/mips/syscallent-n64.h   |  6 +--
 src/linux/mips/syscallent-o32.h   |  6 +--
 src/linux/powerpc/syscallent.h    |  6 +--
 src/linux/powerpc64/syscallent.h  |  6 +--
 src/linux/s390/syscallent.h       |  6 +--
 src/linux/s390x/syscallent.h      |  6 +--
 src/linux/sh/syscallent.h         |  6 +--
 src/linux/sh64/syscallent.h       |  6 +--
 src/linux/sparc/syscallent.h      |  6 +--
 src/linux/sparc64/syscallent.h    |  6 +--
 src/linux/x32/syscallent.h        |  6 +--
 src/linux/x86_64/syscallent.h     |  6 +--
 src/linux/xtensa/syscallent.h     |  6 +--
 src/strace.c                      | 62 ++++++++++++++++++++--
 src/syscall.c                     |  8 +++
 src/sysent.h                      |  1 +
 src/sysent_shorthand_defs.h       |  2 +
 src/sysent_shorthand_undefs.h     |  1 +
 tests/.gitignore                  |  1 +
 tests/Makefile.am                 |  1 +
 tests/gen_tests.in                |  1 +
 tests/strace-Y-0123456789.c       | 88 +++++++++++++++++++++++++++++++
 38 files changed, 248 insertions(+), 81 deletions(-)
 create mode 100644 tests/strace-Y-0123456789.c

-- 
2.31.1