Re: [PATCH v3 7/7] tools/proctrace: add proctrace tool

[Wei Liu <wl@xxxxxxx>]

On Mon, Jun 22, 2020 at 08:12:56PM +0200, Michał Leszczyński wrote:
> Add an demonstration tool that uses xc_vmtrace_* calls in order
> to manage external IPT monitoring for DomU.
> 
> Signed-off-by: Michal Leszczynski <michal.leszczynski@xxxxxxx>
> ---
>  tools/proctrace/COPYING     | 339 ++++++++++++++++++++++++++++++++++++
>  tools/proctrace/Makefile    |  50 ++++++
>  tools/proctrace/proctrace.c | 158 +++++++++++++++++
>  3 files changed, 547 insertions(+)
>  create mode 100644 tools/proctrace/COPYING
>  create mode 100644 tools/proctrace/Makefile
>  create mode 100644 tools/proctrace/proctrace.c
> 
> diff --git a/tools/proctrace/COPYING b/tools/proctrace/COPYING
> new file mode 100644
> index 0000000000..c0a841112c
> --- /dev/null
> +++ b/tools/proctrace/COPYING
> @@ -0,0 +1,339 @@
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> diff --git a/tools/proctrace/Makefile b/tools/proctrace/Makefile
> new file mode 100644
> index 0000000000..76d7387a64
> --- /dev/null
> +++ b/tools/proctrace/Makefile
> @@ -0,0 +1,50 @@
> +# Copyright (C) CERT Polska - NASK PIB
> +# Author: Michał Leszczyński <michal.leszczynski@xxxxxxx>
> +#
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; under version 2 of the License.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +
> +XEN_ROOT=$(CURDIR)/../..
> +include $(XEN_ROOT)/tools/Rules.mk
> +
> +CFLAGS  += -Werror
> +CFLAGS  += $(CFLAGS_libxenevtchn)
> +CFLAGS  += $(CFLAGS_libxenctrl)
> +LDLIBS  += $(LDLIBS_libxenctrl)
> +LDLIBS  += $(LDLIBS_libxenevtchn)
> +LDLIBS  += $(LDLIBS_libxenforeignmemory)
> +
> +# SCRIPTS = xenmon.py
> +

Please drop this line.

> +.PHONY: all
> +all: build
> +
> +.PHONY: build
> +build: proctrace
> +
> +.PHONY: install
> +install: build
> +     $(INSTALL_DIR) $(DESTDIR)$(sbindir)
> +     $(INSTALL_PROG) proctrace $(DESTDIR)$(sbindir)/proctrace
> +
> +.PHONY: uninstall
> +uninstall:
> +     rm -f $(DESTDIR)$(sbindir)/proctrace
> +
> +.PHONY: clean
> +clean:
> +     $(RM) -f $(DEPS_RM)
> +
> +.PHONY: distclean
> +distclean: clean
> +
> +iptlive: iptlive.o Makefile
> +     $(CC) $(LDFLAGS) $< -o $@ $(LDLIBS) $(APPEND_LDFLAGS)
> +
> +-include $(DEPS_INCLUDE)
> diff --git a/tools/proctrace/proctrace.c b/tools/proctrace/proctrace.c
> new file mode 100644
> index 0000000000..dddc6515f8
> --- /dev/null
> +++ b/tools/proctrace/proctrace.c
> @@ -0,0 +1,158 @@
> +/******************************************************************************
> + * tools/proctrace.c
> + *
> + * Demonstrative tool for collecting Intel Processor Trace data from Xen.
> + *  Could be used to externally monitor a given vCPU in given DomU.
> + *
> + * Copyright (C) 2020 by CERT Polska - NASK PIB
> + *
> + * Authors: Michał Leszczyński, michal.leszczynski@xxxxxxx
> + * Date:    June, 2020
> + * 
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; under version 2 of the License.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <time.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <sys/mman.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <errno.h>
> +#include <signal.h>
> +#include <xenevtchn.h>
> +#include <xenctrl.h>
> +#include <xen/xen.h>
> +#include <string.h>
> +#include <sys/select.h>
> +#include <getopt.h>
> +

Do yo really need so many headers? For one, I don't think you used
getopt anywhere.

> +#include <xen/xen.h>
> +#include <xen/trace.h>
> +#include <xenforeignmemory.h>
> +#define XC_WANT_COMPAT_MAP_FOREIGN_API

Would be nice if you don't use the compat API. They are for
compatibility with old code. Since you're writing new code, the
non-compat APIs are preferred.

This is something for you to consider. For simple programs like this I
won't insist.

> +#include <xenevtchn.h>
> +#include <xenctrl.h>
> +
> +#define BUF_SIZE 16384 * 4096
> +

#define BUF_SIZE (16384 * 4096)

> +volatile int interrupted = 0;
> +
> +void term_handler(int signum) {
> +    interrupted = 1;
> +}
> +
> +int main(int argc, char* argv[]) {
> +    xc_interface *xc;
> +    uint32_t domid;
> +    uint32_t vcpu_id;
> +
> +    int rc = -1;
> +    uint8_t *buf = NULL;
> +    uint64_t last_offset = 0;
> +
> +    xenforeignmemory_handle* fmem;

Please put * before fmem to be consistent.

> +    xenforeignmemory_resource_handle *fres;
> +
> +    signal(SIGINT, term_handler);

You should perhaps check the return value of signal here.

> +
> +    if (argc != 3) {
> +        fprintf(stderr, "Usage: %s <domid> <vcpu_id>\n", argv[0]);
> +        fprintf(stderr, "It's recommended to redirect this"
> +                        "program's output to file\n");
> +        fprintf(stderr, "or to pipe it's output to xxd or other program.\n");
> +        return 1;
> +    }
> +
> +    domid = atoi(argv[1]);
> +    vcpu_id = atoi(argv[2]);
> +
> +    xc = xc_interface_open(0, 0, 0);
> +
> +    fmem = xenforeignmemory_open(0, 0);
> +
> +    if (!xc) {
> +        fprintf(stderr, "Failed to open xc interface\n");
> +        return 1;
> +    }
> +
> +    rc = xc_vmtrace_pt_enable(xc, domid, vcpu_id);
> +
> +    if (rc) {
> +        fprintf(stderr, "Failed to call xc_vmtrace_pt_enable\n");
> +        return 1;
> +    }
> +
> +    fres = xenforeignmemory_map_resource(
> +        fmem, domid, XENMEM_resource_vmtrace_buf,
> +        /* vcpu: */ vcpu_id,
> +        /* frame: */ 0,
> +        /* num_frames: */ BUF_SIZE >> XC_PAGE_SHIFT,
> +        (void **)&buf,
> +        PROT_READ, 0);
> +
> +    if (!buf) {
> +        fprintf(stderr, "Failed to map trace buffer\n");
> +        return 1;
> +    }
> +
> +    while (!interrupted) {
> +        uint64_t offset;
> +        rc = xc_vmtrace_pt_get_offset(xc, domid, vcpu_id, &offset);
> +
> +        if (rc) {
> +            fprintf(stderr, "Failed to call xc_vmtrace_pt_get_offset\n");
> +            return 1;
> +        }
> +
> +        if (offset > last_offset)
> +        {
> +            fwrite(buf + last_offset, offset - last_offset, 1, stdout);
> +        }
> +        else if (offset < last_offset)
> +        {
> +            // buffer wrapped
> +            fwrite(buf + last_offset, BUF_SIZE - last_offset, 1, stdout);
> +            fwrite(buf, offset, 1, stdout);
> +        }
> +
> +        last_offset = offset;
> +        usleep(1000 * 100);
> +    }
> +
> +    rc = xenforeignmemory_unmap_resource(fmem, fres);
> +
> +    if (rc) {
> +        fprintf(stderr, "Failed to unmap resource\n");
> +        return 1;
> +    }
> +
> +    rc = xc_vmtrace_pt_disable(xc, domid, vcpu_id);
> +
> +    if (rc) {
> +        fprintf(stderr, "Failed to call xc_vmtrace_pt_disable\n");
> +        return 1;
> +    }
> +

You should close fmem and xc in the exit path.

Wei.

> +    return 0;
> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * tab-width: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> -- 
> 2.20.1
> 
>