Re: [ERROR] perf build failure on current tip:perf/core

[Namhyung Kim <namhyung@gmail.com>]

Ingo Molnar <mingo@elte.hu> wrote:

> * Namhyung Kim <namhyung@gmail.com> wrote:
>
>> 2012-01-08 (일), 10:00 +0100, Ingo Molnar:
>> > * Namhyung Kim <namhyung@gmail.com> wrote:
>> > 
>> > > Hi,
>> > > 
>> > > When I tried to build perf, I was faced with following error:
>> > > 
>> > >     CC util/trace-event-info.o
>> > > cc1: warnings being treated as errors
>> > > util/trace-event-info.c: In function ‘record_file’:
>> > > util/trace-event-info.c:192: error: implicit declaration of function
>> > > ‘pwrite’
>> > > util/trace-event-info.c:192: error: nested extern declaration of
>> > > ‘pwrite’
>> > > make: *** [util/trace-event-info.o] Error 1
>> > > 
>> > > The code I tried was latest tip:perf/core - 9e183426bfb5 ("perf kvm: Fix
>> > > copy & paste error in description") and code in mainline (v3.2) doesn't
>> > > have this problem. Looking at the code, I couldn't find any clue to
>> > > this. Any idea?
>> > > 
>> > > FYI, my system is Ubuntu 10.04 on x86_64. gcc version is 4.4.3:
>> > 
>> > Which header does pwrite() belong to on that system - what does 
>> > 'map pwrite' say? It ought to be unistd.h, which is directly 
>> > included in util/trace-event-info.c.
>> > 
>> > My guess is that it might be related to:
>> > 
>> > tools/perf/Makefile:ALL_CFLAGS = $(CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
>> > 
>> > Which introduces pwrite64() and defines pwrite() to them.
>> > 
>> > Does the patch below help? It's only a workaround really as 
>> > pwrite() ought to exist ... Also, i have only tested this on 
>> > 64-bit.
>> > 
>> > Thanks,
>> > 
>> > 	Ingo
>> > 
>> > diff --git a/tools/perf/util/trace-event-info.c b/tools/perf/util/trace-event-info.c
>> > index ac6830d..ba8b024 100644
>> > --- a/tools/perf/util/trace-event-info.c
>> > +++ b/tools/perf/util/trace-event-info.c
>> > @@ -189,7 +189,7 @@ static void record_file(const char *file, size_t hdr_sz)
>> >  	if (bigendian())
>> >  		sizep += sizeof(u64) - hdr_sz;
>> >  
>> > -	if (hdr_sz && pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0)
>> > +	if (hdr_sz && pwrite64(output_fd, sizep, hdr_sz, hdr_pos) < 0)
>> >  		die("writing to %s", output_file);
>> >  }
>> >  
>> 
>> Hello,
>> 
>> Unfortunately, above patch doesn't work for my system:
>> 
>>       CC util/trace-event-info.o
>>   cc1: warnings being treated as errors
>>   util/trace-event-info.c: In function ‘record_file’:
>>   util/trace-event-info.c:192: error: implicit declaration of function
>> ‘pwrite64’
>>   util/trace-event-info.c:192: error: nested extern declaration of
>> ‘pwrite64’
>> 
>> And 'map pwrite' on terminal says:
>
> 'man pwrite' i wanted to say.

Ah, OK :) here it is.

PREAD(2)                  Linux Programmer's Manual                     PREAD(2)

NAME
       pread, pwrite - read from or write to a file descriptor at a given offset

SYNOPSIS
       #define _XOPEN_SOURCE 500

       #include <unistd.h>

       ssize_t pread(int fd, void *buf, size_t count, off_t offset);

       ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
...

And #defining _XOPEN_SOURCE to 500 before the #include doesn't resolve the issue.


>
>>   $ map pwrite
>>   The program 'map' is currently not installed.  You can install it by
>> typing:
>>   sudo apt-get install sgt-puzzles
>> 
>> I don't think this is the package what you said. Anyway quick grep'ing
>> pwrite tells me it's in the unistd.h:
>> 
>>   $ grep pwrite /usr/include/unistd.h
>>   extern ssize_t pwrite (int __fd, __const void *__buf, size_t __n,
>>   extern ssize_t __REDIRECT (pwrite, (int __fd, __const void *__buf,
>> 			     pwrite64) __wur;
>>   #   define pwrite pwrite64
>
> There's multiple definitions there, and we get lost somehow - as 
> unistd.h is included:
>
>   ~/tip/tools/perf> grep -n unistd.h util/trace-event-info.c
>   34:#include <unistd.h>
>
> Thanks,
>
> 	Ingo

This is the content of my /usr/include/unistd.h:

#ifdef __USE_UNIX98
# ifndef __USE_FILE_OFFSET64
extern ssize_t pread (int __fd, void *__buf, size_t __nbytes,
		      __off_t __offset) __wur;
extern ssize_t pwrite (int __fd, __const void *__buf, size_t __n,
		       __off_t __offset) __wur;
# else
#  ifdef __REDIRECT
extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes,
				   __off64_t __offset),
			   pread64) __wur;
extern ssize_t __REDIRECT (pwrite, (int __fd, __const void *__buf,
				    size_t __nbytes, __off64_t __offset),
			   pwrite64) __wur;
#  else
#   define pread pread64
#   define pwrite pwrite64
#  endif
# endif

# ifdef __USE_LARGEFILE64
extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes,
			__off64_t __offset) __wur;
extern ssize_t pwrite64 (int __fd, __const void *__buf, size_t __n,
			 __off64_t __offset) __wur;
# endif
#endif

I think all of pread/write functions are properly defined here:

  $ echo '#include <unistd.h>' | \
  > gcc -xc -E -dM -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 - | \
  > grep -e UNIX98 -e LARGEFILE64 -e FILE_OFFSET
  #define __ILP32_OFFBIG_CFLAGS "-m32 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64"
  #define _LARGEFILE64_SOURCE 1
  #define __USE_UNIX98 1
  #define __USE_LARGEFILE64 1
  #define _FILE_OFFSET_BITS 64
  #define __USE_FILE_OFFSET64 1

Thanks,
Namhyung