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[PATCH] Fix CMSG_DATA for non-GCC pre-C99 compilers

To: Ulrich Drepper <drepper at redhat dot com>
Subject: [PATCH] Fix CMSG_DATA for non-GCC pre-C99 compilers
From: Jakub Jelinek <jakub at redhat dot com>
Date: Tue, 25 Sep 2001 11:40:23 +0200
Cc: Glibc hackers <libc-hacker at sources dot redhat dot com>
Reply-To: Jakub Jelinek <jakub at redhat dot com>

Hi!

If we declare __cmsg_data field with __flexarr on non-GCC pre-C99 compiler,
it will be __cmsg_data[1], CMSG_DATA macro will expand to
((struct cmsghdr *) (cmsg) + 1)) where struct cmsghdr will have wrong size
because __flexarr is non-zero size array.
This patch should fix it by only defining __cmsg_data field if __flexarr
will have zero size and using the same condition to choose between CMSG_DATA
definitions.
Other solution is to kill the __GNUC__ >= 2 || __STDC_VERSION__ >= 199901L
variants, not use __flexarr at all and have just one CMSG_DATA definition.
But with __cmsg_data it is probably more clear what the intent is.

2001-09-25  Jakub Jelinek  <jakub@redhat.com>

	* sysdeps/unix/bsd/bsd4.4/bits/socket.h (struct cmsghdr): Don't
	declare __cmsg_data field if its size would be bigger than 0.
	(CMSG_DATA): Adjust accordingly.
	* sysdeps/unix/sysv/aix/bits/socket.h: Likewise.
	* sysdeps/unix/sysv/linux/alpha/bits/socket.h: Likewise.
	* sysdeps/unix/sysv/linux/ia64/bits/socket.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/bits/socket.h: Likewise.
	* sysdeps/unix/sysv/linux/bits/socket.h: Likewise.
	* sysdeps/unix/sysv/linux/mips/bits/socket.h: Likewise.
	* sysdeps/unix/sysv/linux/sparc/bits/socket.h: Likewise.

--- libc/sysdeps/unix/bsd/bsd4.4/bits/socket.h.jj	Thu Aug 23 00:29:39 2001
+++ libc/sysdeps/unix/bsd/bsd4.4/bits/socket.h	Tue Sep 25 13:28:46 2001
@@ -199,12 +199,13 @@ struct cmsghdr
 				   of cmsghdr structure.  */
     int cmsg_level;		/* Originating protocol.  */
     int cmsg_type;		/* Protocol specific type.  */
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
     __extension__ unsigned char __cmsg_data __flexarr; /* Ancillary data.  */
-    /* XXX Perhaps this should be removed.  */
+#endif
   };
 
 /* Ancillary data object manipulation macros.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
 # define CMSG_DATA(cmsg) ((cmsg)->__cmsg_data)
 #else
 # define CMSG_DATA(cmsg) ((unsigned char *) ((struct cmsghdr *) (cmsg) + 1))
--- libc/sysdeps/unix/sysv/aix/bits/socket.h.jj	Thu Aug 23 18:50:40 2001
+++ libc/sysdeps/unix/sysv/aix/bits/socket.h	Tue Sep 25 13:32:22 2001
@@ -203,14 +203,13 @@ struct cmsghdr
 				   of cmsghdr structure.  */
     int cmsg_level;		/* Originating protocol.  */
     int cmsg_type;		/* Protocol specific type.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
-    unsigned char __cmsg_data[0]; /* Ancillary data.  */
-    /* XXX Perhaps this should be removed.  */
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
+    __extension__ unsigned char __cmsg_data __flexarr; /* Ancillary data.  */
 #endif
   };
 
 /* Ancillary data object manipulation macros.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
 # define CMSG_DATA(cmsg) ((cmsg)->__cmsg_data)
 #else
 # define CMSG_DATA(cmsg) ((unsigned char *) ((struct cmsghdr *) (cmsg) + 1))
--- libc/sysdeps/unix/sysv/linux/alpha/bits/socket.h.jj	Thu Aug 23 18:50:48 2001
+++ libc/sysdeps/unix/sysv/linux/alpha/bits/socket.h	Tue Sep 25 13:30:04 2001
@@ -233,12 +233,13 @@ struct cmsghdr
 				   of cmsghdr structure.  */
     int cmsg_level;		/* Originating protocol.  */
     int cmsg_type;		/* Protocol specific type.  */
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
     __extension__ unsigned char __cmsg_data __flexarr; /* Ancillary data.  */
-    /* XXX Perhaps this should be removed.  */
+#endif
   };
 
 /* Ancillary data object manipulation macros.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
 # define CMSG_DATA(cmsg) ((cmsg)->__cmsg_data)
 #else
 # define CMSG_DATA(cmsg) ((unsigned char *) ((struct cmsghdr *) (cmsg) + 1))
--- libc/sysdeps/unix/sysv/linux/ia64/bits/socket.h.jj	Thu Aug 23 18:51:06 2001
+++ libc/sysdeps/unix/sysv/linux/ia64/bits/socket.h	Tue Sep 25 13:30:40 2001
@@ -233,12 +233,13 @@ struct cmsghdr
 				   of cmsghdr structure.  */
     int cmsg_level;		/* Originating protocol.  */
     int cmsg_type;		/* Protocol specific type.  */
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
     __extension__ unsigned char __cmsg_data __flexarr; /* Ancillary data.  */
-    /* XXX Perhaps this should be removed.  */
+#endif
   };
 
 /* Ancillary data object manipulation macros.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
 # define CMSG_DATA(cmsg) ((cmsg)->__cmsg_data)
 #else
 # define CMSG_DATA(cmsg) ((unsigned char *) ((struct cmsghdr *) (cmsg) + 1))
--- libc/sysdeps/unix/sysv/linux/s390/s390-64/bits/socket.h.jj	Thu Aug 23 18:51:29 2001
+++ libc/sysdeps/unix/sysv/linux/s390/s390-64/bits/socket.h	Tue Sep 25 13:31:03 2001
@@ -233,12 +233,13 @@ struct cmsghdr
 				   of cmsghdr structure.  */
     int cmsg_level;		/* Originating protocol.  */
     int cmsg_type;		/* Protocol specific type.  */
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
     __extension__ unsigned char __cmsg_data __flexarr; /* Ancillary data.  */
-    /* XXX Perhaps this should be removed.  */
+#endif
   };
 
 /* Ancillary data object manipulation macros.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
 # define CMSG_DATA(cmsg) ((cmsg)->__cmsg_data)
 #else
 # define CMSG_DATA(cmsg) ((unsigned char *) ((struct cmsghdr *) (cmsg) + 1))
--- libc/sysdeps/unix/sysv/linux/bits/socket.h.jj	Thu Aug 23 18:50:53 2001
+++ libc/sysdeps/unix/sysv/linux/bits/socket.h	Tue Sep 25 13:31:27 2001
@@ -233,12 +233,13 @@ struct cmsghdr
 				   of cmsghdr structure.  */
     int cmsg_level;		/* Originating protocol.  */
     int cmsg_type;		/* Protocol specific type.  */
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
     __extension__ unsigned char __cmsg_data __flexarr; /* Ancillary data.  */
-    /* XXX Perhaps this should be removed.  */
+#endif
   };
 
 /* Ancillary data object manipulation macros.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
 # define CMSG_DATA(cmsg) ((cmsg)->__cmsg_data)
 #else
 # define CMSG_DATA(cmsg) ((unsigned char *) ((struct cmsghdr *) (cmsg) + 1))
--- libc/sysdeps/unix/sysv/linux/mips/bits/socket.h.jj	Thu Aug 23 18:51:19 2001
+++ libc/sysdeps/unix/sysv/linux/mips/bits/socket.h	Tue Sep 25 13:31:41 2001
@@ -233,12 +233,13 @@ struct cmsghdr
 				   of cmsghdr structure.  */
     int cmsg_level;		/* Originating protocol.  */
     int cmsg_type;		/* Protocol specific type.  */
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
     __extension__ unsigned char __cmsg_data __flexarr; /* Ancillary data.  */
-    /* XXX Perhaps this should be removed.  */
+#endif
   };
 
 /* Ancillary data object manipulation macros.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
 # define CMSG_DATA(cmsg) ((cmsg)->__cmsg_data)
 #else
 # define CMSG_DATA(cmsg) ((unsigned char *) ((struct cmsghdr *) (cmsg) + 1))
--- libc/sysdeps/unix/sysv/linux/sparc/bits/socket.h.jj	Thu Aug 23 18:51:33 2001
+++ libc/sysdeps/unix/sysv/linux/sparc/bits/socket.h	Tue Sep 25 13:31:54 2001
@@ -239,12 +239,13 @@ struct cmsghdr
 				   of cmsghdr structure.  */
     int cmsg_level;		/* Originating protocol.  */
     int cmsg_type;		/* Protocol specific type.  */
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
     __extension__ unsigned char __cmsg_data __flexarr; /* Ancillary data.  */
-    /* XXX Perhaps this should be removed.  */
+#endif
   };
 
 /* Ancillary data object manipulation macros.  */
-#if !defined __STRICT_ANSI__ && defined __GNUC__ && __GNUC__ >= 2
+#if (!defined __STRICT_ANSI__ && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L
 # define CMSG_DATA(cmsg) ((cmsg)->__cmsg_data)
 #else
 # define CMSG_DATA(cmsg) ((unsigned char *) ((struct cmsghdr *) (cmsg) + 1))

	Jakub

Follow-Ups:
- Re: [PATCH] Fix CMSG_DATA for non-GCC pre-C99 compilers
  - From: Ulrich Drepper

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