[PATCH 2/2] selftest: add a test case for PTRACE_PEEKSIGINFO

From: Andrey Vagin
Date: Wed Feb 27 2013 - 09:39:39 EST


* Dump signals from process-wide and per-thread queues with
different sizes of buffers.
* Check error paths for buffers with restricted permissions. A part of
buffer or a whole buffer is for read-only.
* Try to get nonexistent signal.

Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxx>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Pedro Alves <palves@xxxxxxxxxx>
Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
---
tools/testing/selftests/Makefile | 2 +-
tools/testing/selftests/ptrace/Makefile | 5 +
tools/testing/selftests/ptrace/peeksiginfo.c | 214 +++++++++++++++++++++++++++
3 files changed, 220 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/ptrace/Makefile
create mode 100644 tools/testing/selftests/ptrace/peeksiginfo.c

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 85baf11..379ba69 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -1,4 +1,4 @@
-TARGETS = breakpoints kcmp mqueue vm cpu-hotplug memory-hotplug
+TARGETS = breakpoints kcmp mqueue vm cpu-hotplug memory-hotplug ptrace

all:
for TARGET in $(TARGETS); do \
diff --git a/tools/testing/selftests/ptrace/Makefile b/tools/testing/selftests/ptrace/Makefile
new file mode 100644
index 0000000..82ada21
--- /dev/null
+++ b/tools/testing/selftests/ptrace/Makefile
@@ -0,0 +1,5 @@
+CFLAGS += -iquote../../../../include/uapi -Wall
+peeksiginfo: peeksiginfo.c
+
+clean:
+ rm -f peeksiginfo
diff --git a/tools/testing/selftests/ptrace/peeksiginfo.c b/tools/testing/selftests/ptrace/peeksiginfo.c
new file mode 100644
index 0000000..d46558b
--- /dev/null
+++ b/tools/testing/selftests/ptrace/peeksiginfo.c
@@ -0,0 +1,214 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <signal.h>
+#include <unistd.h>
+#include <errno.h>
+#include <linux/types.h>
+#include <sys/wait.h>
+#include <sys/syscall.h>
+#include <sys/user.h>
+#include <sys/mman.h>
+
+#include "linux/ptrace.h"
+
+static int sys_rt_sigqueueinfo(pid_t tgid, int sig, siginfo_t *uinfo)
+{
+ return syscall(SYS_rt_sigqueueinfo, tgid, sig, uinfo);
+}
+
+static int sys_rt_tgsigqueueinfo(pid_t tgid, pid_t tid,
+ int sig, siginfo_t *uinfo)
+{
+ return syscall(SYS_rt_tgsigqueueinfo, tgid, tid, sig, uinfo);
+}
+
+static int sys_ptrace(int request, pid_t pid, void *addr, void *data)
+{
+ return syscall(SYS_ptrace, request, pid, addr, data);
+}
+
+#define SIGNR 10
+#define TEST_SICODE_PRIV -1
+#define TEST_SICODE_SHARE -2
+
+#define err(fmt, ...) \
+ fprintf(stderr, \
+ "Error (%s:%d): " fmt, \
+ __FILE__, __LINE__, ##__VA_ARGS__)
+
+static int check_error_paths(pid_t child)
+{
+ struct ptrace_peeksiginfo_args arg;
+ int ret, exit_code = -1;
+ void *addr_rw, *addr_ro;
+
+ /*
+ * Allocate two contiguous pages. The first one is for read-write,
+ * another is for read-only.
+ */
+ addr_rw = mmap(NULL, 2 * PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (addr_rw == MAP_FAILED) {
+ err("mmap() failed: %m\n");
+ return 1;
+ }
+
+ addr_ro = mmap(addr_rw + PAGE_SIZE, PAGE_SIZE, PROT_READ,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+ if (addr_ro == MAP_FAILED) {
+ err("mmap() failed: %m\n");
+ goto out;
+ }
+
+ arg.nr = SIGNR;
+ arg.off = 0;
+
+ /* Unsupported flags */
+ arg.flags = ~0;
+ ret = sys_ptrace(PTRACE_PEEKSIGINFO, child, &arg, addr_rw);
+ if (ret != -1 || errno != EINVAL) {
+ err("sys_ptrace() returns %d (expected -1),"
+ " errno %d (expected %d): %m\n",
+ ret, errno, EINVAL);
+ goto out;
+ }
+ arg.flags = 0;
+
+ /* A part of the buffer is read-only */
+ ret = sys_ptrace(PTRACE_PEEKSIGINFO, child, &arg,
+ addr_ro - sizeof(siginfo_t) * 2);
+ if (ret != 2) {
+ err("sys_ptrace() returns %d (expected 2): %m\n", ret);
+ goto out;
+ }
+
+ /* Read-only buffer */
+ ret = sys_ptrace(PTRACE_PEEKSIGINFO, child, &arg, addr_ro);
+ if (ret != -1 && errno != EFAULT) {
+ err("sys_ptrace() returns %d (expected -1),"
+ " errno %d (expected %d): %m\n",
+ ret, errno, EFAULT);
+ goto out;
+ }
+
+ exit_code = 0;
+out:
+ munmap(addr_rw, 2 * PAGE_SIZE);
+ return exit_code;
+}
+
+int check_direct_path(pid_t child, int shared, int nr)
+{
+ struct ptrace_peeksiginfo_args arg = {.flags = 0, .nr = nr, .off = 0};
+ int i, j, ret, exit_code = -1;
+ siginfo_t siginfo[SIGNR];
+ int si_code;
+
+ if (shared == 1) {
+ arg.flags = PTRACE_PEEKSIGINFO_SHARED;
+ si_code = TEST_SICODE_SHARE;
+ } else {
+ arg.flags = 0;
+ si_code = TEST_SICODE_PRIV;
+ }
+
+ for (i = 0; i < SIGNR; ) {
+ arg.off = i;
+ ret = sys_ptrace(PTRACE_PEEKSIGINFO, child, &arg, siginfo);
+ if (ret == -1) {
+ err("ptrace() failed: %m\n");
+ goto out;
+ }
+
+ if (ret == 0)
+ break;
+
+ for (j = 0; j < ret; j++, i++) {
+ if (siginfo[j].si_code == si_code &&
+ siginfo[j].si_int == i)
+ continue;
+
+ err("%d: Wrong siginfo i=%d si_code=%d si_int=%d\n",
+ shared, i, siginfo[j].si_code, siginfo[j].si_int);
+ goto out;
+ }
+ }
+
+ if (i != SIGNR) {
+ err("Only %d signals were read\n", i);
+ goto out;
+ }
+
+ exit_code = 0;
+out:
+ return exit_code;
+}
+
+int main(int argc, char *argv[])
+{
+ siginfo_t siginfo[SIGNR];
+ int i, exit_code = 1;
+ sigset_t blockmask;
+ pid_t child;
+
+ sigemptyset(&blockmask);
+ sigaddset(&blockmask, SIGRTMIN);
+ sigprocmask(SIG_BLOCK, &blockmask, NULL);
+
+ child = fork();
+ if (child == -1) {
+ err("fork() failed: %m");
+ return 1;
+ } else if (child == 0) {
+ pid_t ppid = getppid();
+ while (1) {
+ if (ppid != getppid())
+ break;
+ sleep(1);
+ }
+ return 1;
+ }
+
+ /* Send signals in process-wide and per-thread queues */
+ for (i = 0; i < SIGNR; i++) {
+ siginfo->si_code = TEST_SICODE_SHARE;
+ siginfo->si_int = i;
+ sys_rt_sigqueueinfo(child, SIGRTMIN, siginfo);
+
+ siginfo->si_code = TEST_SICODE_PRIV;
+ siginfo->si_int = i;
+ sys_rt_tgsigqueueinfo(child, child, SIGRTMIN, siginfo);
+ }
+
+ if (sys_ptrace(PTRACE_ATTACH, child, NULL, NULL) == -1)
+ return 1;
+
+ waitpid(child, NULL, 0);
+
+ /* Dump signals one by one*/
+ if (check_direct_path(child, 0, 1))
+ goto out;
+ /* Dump all signals for one call */
+ if (check_direct_path(child, 0, SIGNR))
+ goto out;
+
+ /*
+ * Dump signal from the process-wide queue.
+ * The number of signals is not multible to the buffer size
+ */
+ if (check_direct_path(child, 1, 3))
+ goto out;
+
+ if (check_error_paths(child))
+ goto out;
+
+ printf("PASS\n");
+ exit_code = 0;
+out:
+ if (sys_ptrace(PTRACE_KILL, child, NULL, NULL) == -1)
+ return 1;
+
+ waitpid(child, NULL, 0);
+
+ return exit_code;
+}
--
1.7.11.7

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