Fix Mac OS X build - alternate fdatasync() implementation

[GoogleCodeExporter]

Mac OS X does not implement fdatasync.  The closest equivalent would seem to be 
fcntl(fd, F_FULLFSYNC)

Index: cstdlib/unistd.c
===================================================================
--- cstdlib/unistd.c    (revision 572)
+++ cstdlib/unistd.c    (working copy)
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <limits.h>
+#include <fcntl.h>
 #include "../interpreter.h"

 #ifndef BUILTIN_MINI_STDLIB
@@ -82,7 +83,12 @@

 void UnistdFdatasync(struct ParseState *Parser, struct Value *ReturnValue, struct Value **Param, int NumArgs)
 {
+#ifdef F_FULLFSYNC
+    /* this is a Mac OS X system which does not implement fdatasync as such */
+    ReturnValue->Val->Integer = fcntl(Param[0]->Val->Integer, F_FULLFSYNC);
+#else
     ReturnValue->Val->Integer = fdatasync(Param[0]->Val->Integer);
+#endif
 }

 void UnistdFork(struct ParseState *Parser, struct Value *ReturnValue, struct Value **Param, int NumArgs)

Original issue reported on code.google.com by [email protected] on 13 Nov 2011 at 2:55

[GoogleCodeExporter]

fdatasync() appears to be implemented in current Mac OS X.

Original comment by [email protected] on 1 Mar 2014 at 4:36

• Changed state: WontFix

[GoogleCodeExporter]

It isn't. The only mention of fdatasync() is in <sys/sysproto.h>, as a system 
call; it is not implemented at the library level.

Please re-consider not fixing this; the patch included above has worked well 
for me, and it is correct for both current and older OS X versions.

Original comment by [email protected] on 1 Mar 2014 at 7:55

[GoogleCodeExporter]

picoc compiles without modification on my mac. Here's what I see:

$ make
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o picoc.o 
picoc.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o table.o 
table.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o lex.o lex.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o parse.o 
parse.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
expression.o expression.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o heap.o 
heap.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o type.o 
type.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o variable.o 
variable.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o clibrary.o 
clibrary.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o platform.o 
platform.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o include.o 
include.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o debug.o 
debug.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
platform/platform_unix.o platform/platform_unix.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
platform/library_unix.o platform/library_unix.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/stdio.o cstdlib/stdio.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/math.o cstdlib/math.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/string.o cstdlib/string.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/stdlib.o cstdlib/stdlib.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/time.o cstdlib/time.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/errno.o cstdlib/errno.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/ctype.o cstdlib/ctype.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/stdbool.o cstdlib/stdbool.c
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\"   -c -o 
cstdlib/unistd.o cstdlib/unistd.c
cstdlib/unistd.c:85:33: warning: implicit declaration of function 'fdatasync' 
is invalid in C99 [-Wimplicit-function-declaration]
    ReturnValue->Val->Integer = fdatasync(Param[0]->Val->Integer);
                                ^
cstdlib/unistd.c:266:33: warning: 'sbrk' is deprecated 
[-Wdeprecated-declarations]
    ReturnValue->Val->Pointer = sbrk(Param[0]->Val->Integer);
                                ^
/usr/include/unistd.h:582:7: note: 'sbrk' declared here
void    *sbrk(int);
         ^
2 warnings generated.
gcc -Wall -pedantic -g -DUNIX_HOST -DVER=\"`svnversion -n`\" -o picoc picoc.o 
table.o lex.o parse.o expression.o heap.o type.o variable.o clibrary.o 
platform.o include.o debug.o platform/platform_unix.o platform/library_unix.o 
cstdlib/stdio.o cstdlib/math.o cstdlib/string.o cstdlib/stdlib.o cstdlib/time.o 
cstdlib/errno.o cstdlib/ctype.o cstdlib/stdbool.o cstdlib/unistd.o -lm 
-lreadline


Am I missing something here?

Original comment by [email protected] on 2 Mar 2014 at 12:09

• Changed state: New

[GoogleCodeExporter]

As I noted above, fdatasync isn't implemented at the library level, it's a 
system call and it doesn't take the arguments you're assuming it does.

You don't have a prototype in scope (see the warning, which should be an error) 
and what you're actually linking against is the system call stub:

_fdatasync:
00000000000161d8        movl    $0x20000bb, %eax
00000000000161dd        movq    %rcx, %r10
00000000000161e0        syscall
00000000000161e2        jae     0x161ec
00000000000161e4        movq    %rax, %rdi
00000000000161e7        jmpq    _cerror
00000000000161ec        ret

from <sys/sysproto.h>

struct fdatasync_args {
        char fd_l_[PADL_(int)]; int fd; char fd_r_[PADR_(int)];
};
...
int fdatasync(struct proc *, struct fdatasync_args *, int *);


For whatever reason, it's not surfaced anywhere in a user-callable fashion. The 
F_FULLFSYNC fcntl is the standard mechanism for achieving the equivalent 
functionality on OS X.

Original comment by [email protected] on 2 Mar 2014 at 12:48

[GoogleCodeExporter]

Oh I see. Thanks for that.

Fixed in r608.

Original comment by [email protected] on 2 Mar 2014 at 1:34

• Changed state: Fixed

[GoogleCodeExporter]

Thanks!

Original comment by [email protected] on 2 Mar 2014 at 1:35