[git commit] waitid: linux ABI takes 5 args, not 4

Mike Frysinger vapier at gentoo.org
Wed May 27 23:32:18 UTC 2009


commit: http://git.uclibc.org/uClibc/commit/?id=a282a3fb19fa952a4222a1df9cadbbe553d7169a
branch: http://git.uclibc.org/uClibc/commit/?id=refs/heads/nptl


The POSIX waitid() takes 4 args, but the Linux one takes 5 args, so make
sure we stuff the 5th arg with a NULL.  Otherwise garbage gets randomly
passed up and considering this is a pointer, that's baaaad.

Signed-off-by: Mike Frysinger <vapier at gentoo.org>
Signed-off-by: Austin Foxley <austinf at cetoncorp.com>
---
 libc/sysdeps/linux/common/waitid.c |   57 ++++++++++++++++++++++++++++++++---
 1 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/libc/sysdeps/linux/common/waitid.c b/libc/sysdeps/linux/common/waitid.c
index 2370565..b7930a0 100644
--- a/libc/sysdeps/linux/common/waitid.c
+++ b/libc/sysdeps/linux/common/waitid.c
@@ -5,12 +5,59 @@
  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
  */
 
-#include <sys/syscall.h>
+#include <features.h>
 
 #if defined __USE_SVID || defined __USE_XOPEN
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/wait.h>
+# include <string.h>
+# include <sys/types.h>
+# include <sys/wait.h>
+# include <sys/syscall.h>
+
+# ifdef __NR_waitid
+/* The waitid() POSIX interface takes 4 arguments, but the kernel function
+ * actually takes 5.  The fifth is a pointer to struct rusage.  Make sure
+ * we pass NULL rather than letting whatever was in the register bleed up.
+ */
+#define __NR_waitid5 __NR_waitid
+static _syscall5(int, waitid5, idtype_t, idtype, id_t, id, siginfo_t*, infop,
+                 int, options, struct rusage*, ru)
+# endif
+
+/* libc_hidden_proto(waitpid) */
+int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options)
+{
+# ifdef __NR_waitid
+	return waitid5(idtype, id, infop, options, NULL);
+# else
+	switch (idtype) {
+		case P_PID:
+			if (id <= 0)
+				goto invalid;
+			break;
+		case P_PGID:
+			if (id < 0 || id == 1)
+				goto invalid;
+			id = -id;
+			break;
+		case P_ALL:
+			id = -1;
+			break;
+		default:
+		invalid:
+			__set_errno(EINVAL);
+			return -1;
+	}
+
+	memset(infop, 0, sizeof *infop);
+	infop->si_pid = waitpid(id, &infop->si_status, options
+#  ifdef WEXITED
+					   &~ WEXITED
+#  endif
+					  );
+	if (infop->si_pid < 0)
+		return infop->si_pid;
+	return 0;
+# endif
+}
 
-_syscall4(int, waitid, idtype_t, idtype, id_t, id, siginfo_t*, infop, int, options)
 #endif
-- 
1.6.0.6


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