constants: increase SCTP_DIAG_INFO_LEN to accommodate longer file paths #521

tp-m · 2020-08-25T22:59:02Z

Can happen when used as a meson subproject, for example.

Fixes "‘%s’ directive output truncated writing XX bytes into
a region of size NN [-Wformat-truncation=]" compiler warnings.

tuexen · 2020-08-26T07:18:16Z

I'm using snprintf() intentionally, I want the output to be truncated. On which platform and which compiler produces a warning? What are the warnings? I thought the warning is suppressed by checking the return value of snprintf(). That is why I'm using SCTP_SNPRINTF()...

tp-m · 2020-08-26T09:14:35Z

This happens on debian sid (Linux) with gcc (Debian 10.1.0-6) 10.1.0.

Warnings are:

[3547/4426] Compiling C object subprojects/gst-plugins-bad/ext/sctp/usrsctp/libusrsctp-static.a.p/usrsctplib_netinet_sctp_input.c.o
In file included from ../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os.h:74,
                 from ../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:40:
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c: In function ‘sctp_process_control’:
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: warning: ‘%s’ directive output truncated writing 20 bytes into a region of size 6 [-Wformat-truncation=]
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:4926:5: note: in expansion of macro ‘SCTP_SNPRINTF’
 4926 |     SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |     ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: note: ‘snprintf’ output 143 bytes into a destination of size 128
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:4926:5: note: in expansion of macro ‘SCTP_SNPRINTF’
 4926 |     SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |     ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: warning: ‘%s’ directive output truncated writing 20 bytes into a region of size 6 [-Wformat-truncation=]
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:4882:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 4882 |    SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: note: ‘snprintf’ output 143 bytes into a destination of size 128
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:4882:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 4882 |    SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c: In function ‘sctp_common_input_processing’:
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: warning: ‘%s’ directive output truncated writing 28 bytes into a region of size 6 [-Wformat-truncation=]
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:5914:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 5914 |    SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: note: ‘snprintf’ output 151 bytes into a destination of size 128
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:5914:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 5914 |    SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: warning: ‘%s’ directive output truncated writing 28 bytes into a region of size 6 [-Wformat-truncation=]
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:5997:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 5997 |    SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: note: ‘snprintf’ output 151 bytes into a destination of size 128
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:5997:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 5997 |    SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: warning: ‘%s’ directive output truncated writing 28 bytes into a region of size 6 [-Wformat-truncation=]
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:6083:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 6083 |    SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: note: ‘snprintf’ output 151 bytes into a destination of size 128
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_input.c:6083:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 6083 |    SCTP_SNPRINTF(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
[3593/4426] Compiling C object subprojects/gst-plugins-bad/ext/sctp/usrsctp/libusrsctp-static.a.p/usrsctplib_netinet_sctp_output.c.o
In file included from ../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os.h:74,
                 from ../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c:40:
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c: In function ‘sctp_send_initiate_ack’:
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: warning: ‘%s’ directive output truncated writing 22 bytes into a region of size 11 [-Wformat-truncation=]
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c:6020:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 6020 |    SCTP_SNPRINTF(msg, sizeof(msg), "%s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: note: ‘snprintf’ output 140 bytes into a destination of size 128
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c:6020:4: note: in expansion of macro ‘SCTP_SNPRINTF’
 6020 |    SCTP_SNPRINTF(msg, sizeof(msg), "%s:%d at %s", __FILE__, __LINE__, __func__);
      |    ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c: In function ‘sctp_lower_sosend’:
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: warning: ‘%s’ directive output truncated writing 17 bytes into a region of size 10 [-Wformat-truncation=]
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c:14633:6: note: in expansion of macro ‘SCTP_SNPRINTF’
14633 |      SCTP_SNPRINTF(msg, sizeof(msg),
      |      ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: note: ‘snprintf’ output 136 bytes into a destination of size 128
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c:14633:6: note: in expansion of macro ‘SCTP_SNPRINTF’
14633 |      SCTP_SNPRINTF(msg, sizeof(msg),
      |      ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c: In function ‘sctp_sendall_iterator’:
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: warning: ‘%s’ directive output truncated writing 21 bytes into a region of size 11 [-Wformat-truncation=]
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c:7271:7: note: in expansion of macro ‘SCTP_SNPRINTF’
 7271 |       SCTP_SNPRINTF(msg, sizeof(msg),
      |       ^~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_os_userspace.h:809:6: note: ‘snprintf’ output 139 bytes into a destination of size 128
  809 |  if (snprintf(data, __VA_ARGS__) < 0) {     \
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../home/tpm/Devel/gst-build/subprojects/gst-plugins-bad/ext/sctp/usrsctp/usrsctplib/netinet/sctp_output.c:7271:7: note: in expansion of macro ‘SCTP_SNPRINTF’
 7271 |       SCTP_SNPRINTF(msg, sizeof(msg),
      |       ^~~~~~~~~~~~~

tuexen · 2020-08-26T09:26:53Z

I guess it is time to disable the warning... It doesn't make sense, since I want to output to be truncated if it is too long...

tp-m · 2020-08-26T10:08:37Z

I guess it is time to disable the warning... It doesn't make sense, since I want to output to be truncated if it is too long...

Is there a reason to keep the message buffer length so small though? I mean, why not enlarge it? Performance concerns or?

tuexen · 2020-08-26T10:31:58Z

The buffer is (often) allocated on the stack and the sources are shared with the FreeBSD kernel stack. At least in the kernel, the space on the stack is limited.

I'm fine with the string being truncated, that is why I'm using snprintf(). gcc seems not to like this, don't know why. At some point of time, it was OK to check the return code to avoid this warning. However, in the FreeBSD kernel, snprintf() never fails. So I introduced a macro to deal with this. But newer gcc versions seem not to support the usage of snprintf() with truncation intended...

tp-m · 2020-08-26T10:40:34Z

Ah, I see. Thanks for the explanation.

One could allow a larger buffer #if defined(__Userspace__) but I guess that wouldn't really solve the issue in general, just for my use case :)
The paths for kernel builds are not that long. So it fixes it in the general case, I guess...

tuexen · 2020-08-26T10:42:14Z

We could change it for the userland stack...

Can you use something like

#if defined(__Userspace__)
#define SCTP_DIAG_INFO_LEN 256
#else
#define SCTP_DIAG_INFO_LEN 128
#endif

.. but only for the userspace stack. Can happen when used as a meson subproject, for example. Fixes "‘%s’ directive output truncated writing XX bytes into a region of size NN [-Wformat-truncation=]" compiler warnings with gcc10 on Linux.

tuexen · 2020-08-26T10:53:36Z

Thanks for the patch.

tp-m force-pushed the sctp-diag-info-len branch from 91c55fd to 46c8221 Compare August 26, 2020 10:48

tuexen merged commit df3fb4b into sctplab:master Aug 26, 2020

tp-m deleted the sctp-diag-info-len branch August 26, 2020 10:57

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constants: increase SCTP_DIAG_INFO_LEN to accommodate longer file paths #521

constants: increase SCTP_DIAG_INFO_LEN to accommodate longer file paths #521

tp-m commented Aug 25, 2020

tuexen commented Aug 26, 2020

tp-m commented Aug 26, 2020

tuexen commented Aug 26, 2020

tp-m commented Aug 26, 2020

tuexen commented Aug 26, 2020

tp-m commented Aug 26, 2020 •

edited by tuexen

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tuexen commented Aug 26, 2020

tuexen commented Aug 26, 2020

constants: increase SCTP_DIAG_INFO_LEN to accommodate longer file paths #521

constants: increase SCTP_DIAG_INFO_LEN to accommodate longer file paths #521

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tp-m commented Aug 25, 2020

tuexen commented Aug 26, 2020

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tuexen commented Aug 26, 2020

tp-m commented Aug 26, 2020 •

edited by tuexen

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