Add support for dup3 to syscall.stp tapset.

* tapset/aux_syscalls.stp (_dup3_flag_str): New helper function.
* tapset/syscalls.stp (syscall.dup2): Add alternatives to handle dup3 also.
* testsuite/systemtap.syscall/dup.c: New testcase.

3 files changed, 96 insertions, 0 deletions

diff --git a/tapset/aux_syscalls.stp b/tapset/aux_syscalls.stp
index 87db5abb..15a70484 100644
--- a/tapset/aux_syscalls.stp
+++ b/tapset/aux_syscalls.stp
@@ -1645,6 +1645,16 @@ function _epoll_create1_flag_str:string(f:long)
 #endif
 %}
 
+function _dup3_flag_str:string(f:long)
+%{ /* pure */
+#ifdef O_CLOEXEC
+	if (THIS->f == O_CLOEXEC)
+		strlcpy (THIS->__retvalue, "O_CLOEXEC", MAXSTRINGLEN);
+	else
+#endif
+		strlcpy (THIS->__retvalue, "UNKNOWN", MAXSTRINGLEN);
+%}
+
 %{
 #include <linux/shm.h>
 static const _stp_val_array const _stp_shmat_list[] = {
diff --git a/tapset/syscalls.stp b/tapset/syscalls.stp
index 743318b2..90cdbd0e 100644
--- a/tapset/syscalls.stp
+++ b/tapset/syscalls.stp
@@ -565,9 +565,12 @@ probe syscall.dup.return = kernel.function("SyS_dup").return !,
 
 # dup2 _______________________________________________________
 # long sys_dup2(unsigned int oldfd, unsigned int newfd)
+# Only handles corner case, others handled by dup3.
 probe syscall.dup2 = kernel.function("SyS_dup2").call !,
                      kernel.function("sys_dup2").call
 {
+	if ($oldfd != $newfd) next;
+
 	name = "dup2"
 	oldfd = $oldfd
 	newfd = $newfd
@@ -576,10 +579,50 @@ probe syscall.dup2 = kernel.function("SyS_dup2").call !,
 probe syscall.dup2.return = kernel.function("SyS_dup2").return !,
                             kernel.function("sys_dup2").return
 {
+	if ($oldfd != $newfd) next;
+
 	name = "dup2"
 	retstr = returnstr(1)
 }
 
+# dup3 (handles both dup2 and dup3 except for corner case)___________
+# long sys_dup2(unsigned int oldfd, unsigned int newfd)
+# SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
+probe syscall.dup2 = kernel.function("SyS_dup3").call !,
+                     kernel.function("sys_dup3").call !,
+                     kernel.function("SyS_dup2").call !,
+                     kernel.function("sys_dup2").call
+{
+	oldfd = $oldfd
+	newfd = $newfd
+	flags = @defined($flags) ? $flags : 0;
+
+	# Corner case handled by dup2
+	if ($oldfd == $newfd && flags == 0) next
+
+	if (flags == 0) {
+		name = "dup2";
+		argstr = sprintf("%d, %d", $oldfd, $newfd);
+	} else {
+		name = "dup3";
+		argstr = sprintf("%d, %d, %s", $oldfd, $newfd,
+				 _dup3_flag_str(flags));
+	}
+}
+probe syscall.dup2.return = kernel.function("SyS_dup3").return !,
+                            kernel.function("sys_dup3").return !,
+                            kernel.function("SyS_dup2").return !,
+                            kernel.function("sys_dup2").return
+{
+	flags = @defined($flags) ? $flags : 0;
+
+	# Corner case handled by dup2
+	if ($oldfd == $newfd && flags == 0) next
+
+	name = flags == 0 ? "dup2" : "dup3";
+	retstr = returnstr(1)
+}
+
 # epoll_create _______________________________________________
 # long sys_epoll_create(int size)
 # SYSCALL_DEFINE1(epoll_create1, int, flags)
diff --git a/testsuite/systemtap.syscall/dup.c b/testsuite/systemtap.syscall/dup.c
new file mode 100644
index 00000000..862f7e91
--- /dev/null
+++ b/testsuite/systemtap.syscall/dup.c
@@ -0,0 +1,43 @@
+/* COVERAGE: dup dup2 dup3 */
+
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+int main()
+{
+  dup(2);
+  //staptest// dup (2) = NNNN
+  
+  dup(256);
+  //staptest// dup (256) = -9 (EBADF)
+  
+  dup2(3, 4);
+  //staptest// dup2 (3, 4) = 4
+
+  dup2(255, 256);
+  //staptest// dup2 (255, 256) = -9 (EBADF)
+
+  /* weird corner case oldfd == newfd */
+  dup2(1, 1);
+  //staptest// dup2 (1, 1) = 1
+
+#ifdef O_CLOEXEC
+  dup3 (4, 5, O_CLOEXEC);
+  //staptest// dup3 (4, 5, O_CLOEXEC) = 5
+
+  dup3 (256, 255, O_CLOEXEC);
+  //staptest// dup3 (256, 255, O_CLOEXEC) = -9 (EBADF)
+  
+  dup3 (5, 6, 666);
+  //staptest// dup3 (5, 6, UNKNOWN) = -22 (EINVAL)
+
+  /* corner case not valid for dup3 */
+  dup3 (1, 1, O_CLOEXEC);
+  //staptest// dup3 (1, 1, O_CLOEXEC) = -22 (EINVAL)
+#endif
+
+  return 0;
+}