[PATCH] util: fix building when glibc has a stub process_vm_readv

Mike Frysinger vapier at gentoo.org
Fri May 4 23:37:29 UTC 2012

If you have a newer glibc which provides process_vm_readv, but it is built
against older kernel headers which lack __NR_process_vm_readv, the library
will contain a stub implementation that just returns ENOSYS.  Autoconf
checks for this case explicitly and will declare it as unavailable.  So we
end up in a case where the headers provide the prototype, but autoconf has
not defined HAVE_PROCESS_VM_READV, so we hit the same build failure again:

util.c:738:16: error: static declaration of 'process_vm_readv' follows non-static declaration
/usr/include/bits/uio.h:58:16: note: previous declaration of 'process_vm_readv' was here

So rename our local function to something unique, and add a define so the
callers all hit the right place.

* util.c (strace_process_vm_readv): Rename from process_vm_readv.
(process_vm_readv): Define to strace_process_vm_readv.

Signed-off-by: Mike Frysinger <vapier at gentoo.org>
 util.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/util.c b/util.c
index d347bd8..f27acdf 100644
--- a/util.c
+++ b/util.c
@@ -735,7 +735,8 @@ static bool process_vm_readv_not_supported = 0;
 #if defined(__NR_process_vm_readv)
 static bool process_vm_readv_not_supported = 0;
-static ssize_t process_vm_readv(pid_t pid,
+/* Have to avoid duplicating with the C library headers. */
+static ssize_t strace_process_vm_readv(pid_t pid,
 		 const struct iovec *lvec,
 		 unsigned long liovcnt,
 		 const struct iovec *rvec,
@@ -744,6 +745,7 @@ static ssize_t process_vm_readv(pid_t pid,
 	return syscall(__NR_process_vm_readv, (long)pid, lvec, liovcnt, rvec, riovcnt, flags);
+#define process_vm_readv strace_process_vm_readv
 static bool process_vm_readv_not_supported = 1;
 # define process_vm_readv(...) (errno = ENOSYS, -1)

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