[v3,4/4] test: add a test for the process_vmsplice syscall

Submitted by Mike Rapoport on Nov. 22, 2017, 7:36 p.m.

Details

Message ID 1511379391-988-5-git-send-email-rppt@linux.vnet.ibm.com
State New
Series "vm: add a syscall to map a process memory into a pipe"
Headers show

Commit Message

Mike Rapoport Nov. 22, 2017, 7:36 p.m.
From: Andrei Vagin <avagin@openvz.org>

This test checks that process_vmsplice() can splice pages from a remote
process and returns EFAULT, if process_vmsplice() tries to splice pages
by an unaccessiable address.

Signed-off-by: Andrei Vagin <avagin@openvz.org>
---
 tools/testing/selftests/process_vmsplice/Makefile  |   5 +
 .../process_vmsplice/process_vmsplice_test.c       | 188 +++++++++++++++++++++
 2 files changed, 193 insertions(+)
 create mode 100644 tools/testing/selftests/process_vmsplice/Makefile
 create mode 100644 tools/testing/selftests/process_vmsplice/process_vmsplice_test.c

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diff --git a/tools/testing/selftests/process_vmsplice/Makefile b/tools/testing/selftests/process_vmsplice/Makefile
new file mode 100644
index 0000000..246d5a7
--- /dev/null
+++ b/tools/testing/selftests/process_vmsplice/Makefile
@@ -0,0 +1,5 @@ 
+CFLAGS += -I../../../../usr/include/
+
+TEST_GEN_PROGS := process_vmsplice_test
+
+include ../lib.mk
diff --git a/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c b/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c
new file mode 100644
index 0000000..8abf59b
--- /dev/null
+++ b/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c
@@ -0,0 +1,188 @@ 
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <fcntl.h>
+#include <sys/uio.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+
+#include "../kselftest.h"
+
+#ifndef __NR_process_vmsplice
+#define __NR_process_vmsplice 333
+#endif
+
+#define pr_err(fmt, ...) \
+		({ \
+			fprintf(stderr, "%s:%d:" fmt, \
+				__func__, __LINE__, ##__VA_ARGS__); \
+			KSFT_FAIL; \
+		})
+#define pr_perror(fmt, ...) pr_err(fmt ": %m\n", ##__VA_ARGS__)
+#define fail(fmt, ...) pr_err("FAIL:" fmt, ##__VA_ARGS__)
+
+static ssize_t process_vmsplice(pid_t pid, int fd, const struct iovec *iov,
+			unsigned long nr_segs, unsigned int flags)
+{
+	return syscall(__NR_process_vmsplice, pid, fd, iov, nr_segs, flags);
+
+}
+
+#define MEM_SIZE (4096 * 100)
+#define MEM_WRONLY_SIZE (4096 * 10)
+
+int main(int argc, char **argv)
+{
+	char *addr, *addr_wronly;
+	int p[2];
+	struct iovec iov[2];
+	char buf[4096];
+	int status, ret;
+	pid_t pid;
+
+	ksft_print_header();
+
+	addr = mmap(0, MEM_SIZE, PROT_READ | PROT_WRITE,
+					MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (addr == MAP_FAILED)
+		return pr_perror("Unable to create a mapping");
+
+	addr_wronly = mmap(0, MEM_WRONLY_SIZE, PROT_WRITE,
+				MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (addr_wronly == MAP_FAILED)
+		return pr_perror("Unable to create a write-only mapping");
+
+	if (pipe(p))
+		return pr_perror("Unable to create a pipe");
+
+	pid = fork();
+	if (pid < 0)
+		return pr_perror("Unable to fork");
+
+	if (pid == 0) {
+		addr[0] = 'C';
+		addr[4096 + 128] = 'A';
+		addr[4096 + 128 + 4096 - 1] = 'B';
+
+		if (prctl(PR_SET_PDEATHSIG, SIGKILL))
+			return pr_perror("Unable to set PR_SET_PDEATHSIG");
+		if (write(p[1], "c", 1) != 1)
+			return pr_perror("Unable to write data into pipe");
+
+		while (1)
+			sleep(1);
+		return 1;
+	}
+	if (read(p[0], buf, 1) != 1) {
+		pr_perror("Unable to read data from pipe");
+		kill(pid, SIGKILL);
+		wait(&status);
+		return 1;
+	}
+
+	munmap(addr, MEM_SIZE);
+	munmap(addr_wronly, MEM_WRONLY_SIZE);
+
+	iov[0].iov_base = addr;
+	iov[0].iov_len = 1;
+
+	iov[1].iov_base = addr + 4096 + 128;
+	iov[1].iov_len = 4096;
+
+	/* check one iovec */
+	if (process_vmsplice(pid, p[1], iov, 1, SPLICE_F_GIFT) != 1)
+		return pr_perror("Unable to splice pages");
+
+	if (read(p[0], buf, 1) != 1)
+		return pr_perror("Unable to read from pipe");
+
+	if (buf[0] != 'C')
+		ksft_test_result_fail("Get wrong data\n");
+	else
+		ksft_test_result_pass("Check process_vmsplice with one vec\n");
+
+	/* check two iovec-s */
+	if (process_vmsplice(pid, p[1], iov, 2, SPLICE_F_GIFT) != 4097)
+		return pr_perror("Unable to spice pages\n");
+
+	if (read(p[0], buf, 1) != 1)
+		return pr_perror("Unable to read from pipe\n");
+
+	if (buf[0] != 'C')
+		ksft_test_result_fail("Get wrong data\n");
+
+	if (read(p[0], buf, 4096) != 4096)
+		return pr_perror("Unable to read from pipe\n");
+
+	if (buf[0] != 'A' || buf[4095] != 'B')
+		ksft_test_result_fail("Get wrong data\n");
+	else
+		ksft_test_result_pass("check process_vmsplice with two vecs\n");
+
+	/* check how an unreadable region in a second vec is handled */
+	iov[0].iov_base = addr;
+	iov[0].iov_len = 1;
+
+	iov[1].iov_base = addr_wronly + 5;
+	iov[1].iov_len = 1;
+
+	if (process_vmsplice(pid, p[1], iov, 2, SPLICE_F_GIFT) != 1)
+		return pr_perror("Unable to splice data");
+
+	if (read(p[0], buf, 1) != 1)
+		return pr_perror("Unable to read form pipe");
+
+	if (buf[0] != 'C')
+		ksft_test_result_fail("Get wrong data\n");
+	else
+		ksft_test_result_pass("unreadable region in a second vec\n");
+
+	/* check how an unreadable region in a first vec is handled */
+	errno = 0;
+	if (process_vmsplice(pid, p[1], iov + 1, 1, SPLICE_F_GIFT) != -1 ||
+	    errno != EFAULT)
+		ksft_test_result_fail("Got anexpected errno %d\n", errno);
+	else
+		ksft_test_result_pass("splice as much as possible\n");
+
+	iov[0].iov_base = addr;
+	iov[0].iov_len = 1;
+
+	iov[1].iov_base = addr;
+	iov[1].iov_len = MEM_SIZE;
+
+	/* splice as much as possible */
+	ret = process_vmsplice(pid, p[1], iov, 2,
+				SPLICE_F_GIFT | SPLICE_F_NONBLOCK);
+	if (ret != 4096 * 15 + 1) /* by default a pipe can fit 16 pages */
+		return pr_perror("Unable to splice pages");
+
+	while (ret > 0) {
+		int len;
+
+		len = read(p[0], buf, 4096);
+		if (len < 0)
+			return pr_perror("Unable to read data");
+		if (len > ret)
+			return pr_err("Read more than expected\n");
+		ret -= len;
+	}
+	ksft_test_result_pass("splice as much as possible\n");
+
+	if (kill(pid, SIGTERM))
+		return pr_perror("Unable to kill a child process");
+	status = -1;
+	if (wait(&status) < 0)
+		return pr_perror("Unable to wait a child process");
+	if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGTERM)
+		return pr_err("The child exited with an unexpected code %d\n",
+									status);
+
+	if (ksft_get_fail_cnt())
+		return ksft_exit_fail();
+	return ksft_exit_pass();
+}

Comments

Greg KH Nov. 23, 2017, 8:01 a.m.
On Wed, Nov 22, 2017 at 09:36:31PM +0200, Mike Rapoport wrote:
> From: Andrei Vagin <avagin@openvz.org>
> 
> This test checks that process_vmsplice() can splice pages from a remote
> process and returns EFAULT, if process_vmsplice() tries to splice pages
> by an unaccessiable address.
> 
> Signed-off-by: Andrei Vagin <avagin@openvz.org>
> ---
>  tools/testing/selftests/process_vmsplice/Makefile  |   5 +
>  .../process_vmsplice/process_vmsplice_test.c       | 188 +++++++++++++++++++++
>  2 files changed, 193 insertions(+)
>  create mode 100644 tools/testing/selftests/process_vmsplice/Makefile
>  create mode 100644 tools/testing/selftests/process_vmsplice/process_vmsplice_test.c
> 
> diff --git a/tools/testing/selftests/process_vmsplice/Makefile b/tools/testing/selftests/process_vmsplice/Makefile
> new file mode 100644
> index 0000000..246d5a7
> --- /dev/null
> +++ b/tools/testing/selftests/process_vmsplice/Makefile
> @@ -0,0 +1,5 @@
> +CFLAGS += -I../../../../usr/include/
> +
> +TEST_GEN_PROGS := process_vmsplice_test
> +
> +include ../lib.mk
> diff --git a/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c b/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c
> new file mode 100644
> index 0000000..8abf59b
> --- /dev/null
> +++ b/tools/testing/selftests/process_vmsplice/process_vmsplice_test.c
> @@ -0,0 +1,188 @@
> +#define _GNU_SOURCE
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <sys/mman.h>
> +#include <sys/syscall.h>
> +#include <fcntl.h>
> +#include <sys/uio.h>
> +#include <errno.h>
> +#include <signal.h>
> +#include <sys/prctl.h>
> +#include <sys/wait.h>
> +
> +#include "../kselftest.h"
> +
> +#ifndef __NR_process_vmsplice
> +#define __NR_process_vmsplice 333
> +#endif
> +
> +#define pr_err(fmt, ...) \
> +		({ \
> +			fprintf(stderr, "%s:%d:" fmt, \
> +				__func__, __LINE__, ##__VA_ARGS__); \
> +			KSFT_FAIL; \
> +		})
> +#define pr_perror(fmt, ...) pr_err(fmt ": %m\n", ##__VA_ARGS__)
> +#define fail(fmt, ...) pr_err("FAIL:" fmt, ##__VA_ARGS__)
> +
> +static ssize_t process_vmsplice(pid_t pid, int fd, const struct iovec *iov,
> +			unsigned long nr_segs, unsigned int flags)
> +{
> +	return syscall(__NR_process_vmsplice, pid, fd, iov, nr_segs, flags);
> +
> +}
> +
> +#define MEM_SIZE (4096 * 100)
> +#define MEM_WRONLY_SIZE (4096 * 10)
> +
> +int main(int argc, char **argv)
> +{
> +	char *addr, *addr_wronly;
> +	int p[2];
> +	struct iovec iov[2];
> +	char buf[4096];
> +	int status, ret;
> +	pid_t pid;
> +
> +	ksft_print_header();
> +
> +	addr = mmap(0, MEM_SIZE, PROT_READ | PROT_WRITE,
> +					MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> +	if (addr == MAP_FAILED)
> +		return pr_perror("Unable to create a mapping");
> +
> +	addr_wronly = mmap(0, MEM_WRONLY_SIZE, PROT_WRITE,
> +				MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> +	if (addr_wronly == MAP_FAILED)
> +		return pr_perror("Unable to create a write-only mapping");
> +
> +	if (pipe(p))
> +		return pr_perror("Unable to create a pipe");
> +
> +	pid = fork();
> +	if (pid < 0)
> +		return pr_perror("Unable to fork");
> +
> +	if (pid == 0) {
> +		addr[0] = 'C';
> +		addr[4096 + 128] = 'A';
> +		addr[4096 + 128 + 4096 - 1] = 'B';
> +
> +		if (prctl(PR_SET_PDEATHSIG, SIGKILL))
> +			return pr_perror("Unable to set PR_SET_PDEATHSIG");
> +		if (write(p[1], "c", 1) != 1)
> +			return pr_perror("Unable to write data into pipe");
> +
> +		while (1)
> +			sleep(1);
> +		return 1;
> +	}
> +	if (read(p[0], buf, 1) != 1) {
> +		pr_perror("Unable to read data from pipe");
> +		kill(pid, SIGKILL);
> +		wait(&status);
> +		return 1;
> +	}
> +
> +	munmap(addr, MEM_SIZE);
> +	munmap(addr_wronly, MEM_WRONLY_SIZE);
> +
> +	iov[0].iov_base = addr;
> +	iov[0].iov_len = 1;
> +
> +	iov[1].iov_base = addr + 4096 + 128;
> +	iov[1].iov_len = 4096;
> +
> +	/* check one iovec */
> +	if (process_vmsplice(pid, p[1], iov, 1, SPLICE_F_GIFT) != 1)
> +		return pr_perror("Unable to splice pages");

Shouldn't you check to see if the syscall is even present?  You should
not error if it is not, as this test will then "fail" on kernels/arches
without the syscall enabled, which isn't the nicest.

thanks,

greg k-h
Mike Rapoport Nov. 23, 2017, 2:07 p.m.
On Thu, Nov 23, 2017 at 09:01:03AM +0100, Greg KH wrote:
> On Wed, Nov 22, 2017 at 09:36:31PM +0200, Mike Rapoport wrote:
> > From: Andrei Vagin <avagin@openvz.org>
> > 
> > This test checks that process_vmsplice() can splice pages from a remote
> > process and returns EFAULT, if process_vmsplice() tries to splice pages
> > by an unaccessiable address.
> > 
> > Signed-off-by: Andrei Vagin <avagin@openvz.org>
> > ---
> >  tools/testing/selftests/process_vmsplice/Makefile  |   5 +
> >  .../process_vmsplice/process_vmsplice_test.c       | 188 +++++++++++++++++++++
> >  2 files changed, 193 insertions(+)
> >  create mode 100644 tools/testing/selftests/process_vmsplice/Makefile
> >  create mode 100644 tools/testing/selftests/process_vmsplice/process_vmsplice_test.c
> > 

[ ... ]

> 
> Shouldn't you check to see if the syscall is even present?  You should
> not error if it is not, as this test will then "fail" on kernels/arches
> without the syscall enabled, which isn't the nicest.

Sure, will fix.

> thanks,
> 
> greg k-h
>