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[libvirt] [PATCH 13/17] nss: custom parser for loading .macs file



The .macs file is currently loaded using the virMacMap class,
which in turn uses the virJSON parsing code. This pulls in a
heap of libvirt code (logging, hash tables, objects, etc) which
we do not wish to depend on.

This uses the yajl parser code directly, so the only dep is
yajl and plain libc functions.

Signed-off-by: Daniel P. Berrangé <berrange redhat com>
---
 cfg.mk                       |   6 +-
 tools/Makefile.am            |   6 +-
 tools/nss/libvirt_nss.c      |  70 ++-------
 tools/nss/libvirt_nss.h      |  23 +++
 tools/nss/libvirt_nss_macs.c | 289 +++++++++++++++++++++++++++++++++++
 tools/nss/libvirt_nss_macs.h |  27 ++++
 6 files changed, 360 insertions(+), 61 deletions(-)
 create mode 100644 tools/nss/libvirt_nss_macs.c
 create mode 100644 tools/nss/libvirt_nss_macs.h

diff --git a/cfg.mk b/cfg.mk
index 8c352d7b9a..33bf29c5b0 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -1226,10 +1226,10 @@ exclude_file_name_regexp--sc_prohibit_asprintf = \
   ^(cfg\.mk|bootstrap.conf$$|examples/|src/util/virstring\.[ch]$$|tests/vircgroupmock\.c|tools/virt-login-shell\.c|tools/nss/libvirt_nss\.c$$)
 
 exclude_file_name_regexp--sc_prohibit_strdup = \
-  ^(docs/|examples/|src/util/virstring\.c|tests/vir(netserverclient|cgroup)mock.c|tests/commandhelper\.c|tools/nss/libvirt_nss\.c$$)
+  ^(docs/|examples/|src/util/virstring\.c|tests/vir(netserverclient|cgroup)mock.c|tests/commandhelper\.c|tools/nss/libvirt_nss_macs\.c$$)
 
 exclude_file_name_regexp--sc_prohibit_close = \
-  (\.p[yl]$$|\.spec\.in$$|^docs/|^(src/util/virfile\.c|src/libvirt-stream\.c|tests/(vir.+mock\.c|commandhelper\.c|qemusecuritymock\.c))$$)
+  (\.p[yl]$$|\.spec\.in$$|^docs/|^(src/util/virfile\.c|src/libvirt-stream\.c|tests/(vir.+mock\.c|commandhelper\.c|qemusecuritymock\.c)|tools/nss/libvirt_nss_macs\.c)$$)
 
 exclude_file_name_regexp--sc_prohibit_empty_lines_at_EOF = \
   (^tests/(virhostcpu|virpcitest)data/|docs/js/.*\.js|docs/fonts/.*\.woff|\.diff|tests/virconfdata/no-newline\.conf$$)
@@ -1259,7 +1259,7 @@ exclude_file_name_regexp--sc_prohibit_canonicalize_file_name = \
   ^(cfg\.mk|tests/virfilemock\.c)$$
 
 exclude_file_name_regexp--sc_prohibit_raw_allocation = \
-  ^(docs/hacking\.html\.in|src/util/viralloc\.[ch]|examples/.*|tests/(securityselinuxhelper|(vircgroup|nss)mock|commandhelper)\.c|tools/wireshark/src/packet-libvirt\.c|tools/nss/libvirt_nss\.c)$$
+  ^(docs/hacking\.html\.in|src/util/viralloc\.[ch]|examples/.*|tests/(securityselinuxhelper|(vircgroup|nss)mock|commandhelper)\.c|tools/wireshark/src/packet-libvirt\.c|tools/nss/libvirt_nss(_macs)?\.c)$$
 
 exclude_file_name_regexp--sc_prohibit_readlink = \
   ^src/(util/virutil|lxc/lxc_container)\.c$$
diff --git a/tools/Makefile.am b/tools/Makefile.am
index 3d9461ba65..eee4226231 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -507,11 +507,15 @@ nss_libnss_libvirt_la_LIBADD = \
 
 noinst_LTLIBRARIES += nss/libnss_libvirt_guest_impl.la
 nss_libnss_libvirt_guest_impl_la_SOURCES = \
-	$(LIBVIRT_NSS_SOURCES)
+	$(LIBVIRT_NSS_SOURCES) \
+	nss/libvirt_nss_macs.h \
+	nss/libvirt_nss_macs.c \
+	$(NULL)
 
 nss_libnss_libvirt_guest_impl_la_CFLAGS = \
 	-DLIBVIRT_NSS \
 	-DLIBVIRT_NSS_GUEST \
+	$(YAJL_CFLAGS) \
 	$(AM_CFLAGS) \
 	$(NULL)
 
diff --git a/tools/nss/libvirt_nss.c b/tools/nss/libvirt_nss.c
index a849b8e5f7..b3756b984a 100644
--- a/tools/nss/libvirt_nss.c
+++ b/tools/nss/libvirt_nss.c
@@ -39,32 +39,12 @@
 #include "virlease.h"
 #include "viralloc.h"
 #include "virtime.h"
-#include "virerror.h"
 #include "virsocketaddr.h"
 #include "configmake.h"
-#include "virmacmap.h"
-#include "virobject.h"
-
-#if 0
-# define ERROR(...) \
-do { \
-    char ebuf[1024]; \
-    fprintf(stderr, "ERROR %s:%d : ", __FUNCTION__, __LINE__); \
-    fprintf(stderr, __VA_ARGS__); \
-    fprintf(stderr, " : %s\n", virStrerror(errno, ebuf, sizeof(ebuf))); \
-    fprintf(stderr, "\n"); \
-} while (0)
-
-# define DEBUG(...) \
-do { \
-    fprintf(stderr, "DEBUG %s:%d : ", __FUNCTION__, __LINE__); \
-    fprintf(stderr, __VA_ARGS__); \
-    fprintf(stderr, "\n"); \
-} while (0)
-#else
-# define ERROR(...) do { } while (0)
-# define DEBUG(...) do { } while (0)
-#endif
+
+#if defined(LIBVIRT_NSS_GUEST)
+# include "libvirt_nss_macs.h"
+#endif /* !LIBVIRT_NSS_GUEST */
 
 #define LEASEDIR LOCALSTATEDIR "/lib/libvirt/dnsmasq/"
 
@@ -169,10 +149,12 @@ findLeaseInJSON(leaseAddress **tmpAddress,
                 size_t nleases,
                 const char *name,
                 const char **macs,
+                size_t nmacs,
                 int af,
                 bool *found)
 {
     size_t i;
+    size_t j;
     long long expirytime;
     time_t currtime;
 
@@ -191,7 +173,6 @@ findLeaseInJSON(leaseAddress **tmpAddress,
         }
 
         if (macs) {
-            const char **macstmp = macs;
             const char *macAddr;
             bool match = false;
 
@@ -199,10 +180,9 @@ findLeaseInJSON(leaseAddress **tmpAddress,
             if (!macAddr)
                 continue;
 
-            while (*macstmp && !match) {
-                if (STREQ(*macstmp, macAddr))
+            for (j = 0; j < nmacs && !match; j++) {
+                if (STREQ(macs[j], macAddr))
                     match = true;
-                macstmp++;
             }
             if (!match)
                 continue;
@@ -274,7 +254,6 @@ findLease(const char *name,
     ssize_t nleases;
     VIR_AUTOFREE(leaseAddress *) tmpAddress = NULL;
     size_t ntmpAddress = 0;
-    virMacMapPtr map = NULL;
     char **macs = NULL;
     size_t nmacs = 0;
     size_t i;
@@ -317,40 +296,15 @@ findLease(const char *name,
             VIR_FREE(path);
 #if defined(LIBVIRT_NSS_GUEST)
         } else if (dlen >= 5 && STREQ(entry->d_name + dlen - 5, ".macs")) {
-            const char * const *newmacs;
             if (asprintf(&path, "%s/%s", leaseDir, entry->d_name) < 0)
                 goto cleanup;
 
             DEBUG("Processing %s", path);
-            if (!(map = virMacMapNew(path))) {
-                ERROR("Unable to parse %s", path);
+            if (findMACs(path, name, &macs, &nmacs) < 0) {
                 VIR_FREE(path);
                 goto cleanup;
             }
             VIR_FREE(path);
-
-            DEBUG("Looking up macs in %p for %s", map, name);
-            newmacs = virMacMapLookup(map, name);
-            for (i = 0; newmacs && newmacs[i] != NULL; i++)
-                ;
-
-            DEBUG("Got %zu macs", i);
-            if (i > 0) {
-                if (VIR_REALLOC_N_QUIET(macs, nmacs + i + 1) < 0)
-                    goto cleanup;
-
-                for (i = 0; newmacs[i] != NULL; i++) {
-                    char *macdup;
-                    if (!(macdup = strdup(newmacs[i])))
-                        goto cleanup;
-                    DEBUG("Capture mac %s", macdup);
-                    macs[nmacs++] = macdup;
-                }
-                macs[nmacs] = NULL;
-            }
-
-            virObjectUnref(map);
-            map = NULL;
 #endif /* LIBVIRT_NSS_GUEST */
         }
 
@@ -366,11 +320,14 @@ findLease(const char *name,
     DEBUG("Finding with %zu macs", nmacs);
     if (!nmacs)
         goto cleanup;
+    for (i = 0; i < nmacs; i++)
+        DEBUG("  %s", macs[i]);
 #endif
 
     if (findLeaseInJSON(&tmpAddress, &ntmpAddress,
                         leases_array, nleases,
-                        name, (const char**)macs, af, found) < 0)
+                        name, (const char**)macs, nmacs,
+                        af, found) < 0)
         goto cleanup;
 
     DEBUG("Found %zu addresses", ntmpAddress);
@@ -383,7 +340,6 @@ findLease(const char *name,
     ret = 0;
 
  cleanup:
-    virObjectUnref(map);
     *errnop = errno;
     for (i = 0; i < nmacs; i++)
         free(macs[i]);
diff --git a/tools/nss/libvirt_nss.h b/tools/nss/libvirt_nss.h
index 75a2e4fd93..6e4be125d2 100644
--- a/tools/nss/libvirt_nss.h
+++ b/tools/nss/libvirt_nss.h
@@ -28,6 +28,29 @@
 #include <nss.h>
 #include <netdb.h>
 
+
+#if 0
+# include "virerror.h"
+# define ERROR(...) \
+do { \
+    char ebuf[1024]; \
+    fprintf(stderr, "ERROR %s:%d : ", __FUNCTION__, __LINE__); \
+    fprintf(stderr, __VA_ARGS__); \
+    fprintf(stderr, " : %s\n", virStrerror(errno, ebuf, sizeof(ebuf))); \
+    fprintf(stderr, "\n"); \
+} while (0)
+
+# define DEBUG(...) \
+do { \
+    fprintf(stderr, "DEBUG %s:%d : ", __FUNCTION__, __LINE__); \
+    fprintf(stderr, __VA_ARGS__); \
+    fprintf(stderr, "\n"); \
+} while (0)
+#else
+# define ERROR(...) do { } while (0)
+# define DEBUG(...) do { } while (0)
+#endif
+
 #if !defined(LIBVIRT_NSS_GUEST)
 # define NSS_NAME(s) _nss_libvirt_##s##_r
 #else
diff --git a/tools/nss/libvirt_nss_macs.c b/tools/nss/libvirt_nss_macs.c
new file mode 100644
index 0000000000..0d0b6b1eaa
--- /dev/null
+++ b/tools/nss/libvirt_nss_macs.c
@@ -0,0 +1,289 @@
+/*
+ * libvirt_nss_macs.c: Name Service Switch plugin MAC file parser
+ *
+ * Copyright (C) 2019 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+#include <yajl/yajl_gen.h>
+#include <yajl/yajl_parse.h>
+
+#include "internal.h"
+
+#include "libvirt_nss.h"
+#include "libvirt_nss_macs.h"
+
+enum {
+    FIND_MACS_STATE_START,
+    FIND_MACS_STATE_LIST,
+    FIND_MACS_STATE_ENTRY,
+    FIND_MACS_STATE_ENTRY_MACS,
+};
+
+typedef struct {
+    const char *name;
+    char ***macs;
+    size_t *nmacs;
+    int state;
+
+    char *key;
+    struct {
+        char *name;
+        char **macs;
+        size_t nmacs;
+    } entry;
+} findMACsParser;
+
+
+static int
+findMACsParserString(void *ctx,
+                    const unsigned char *stringVal,
+                    size_t stringLen)
+{
+    findMACsParser *parser = ctx;
+
+    DEBUG("Parse string state=%d '%.*s' (map key '%s')",
+          parser->state, (int)stringLen, (const char *)stringVal,
+          NULLSTR(parser->key));
+    if (!parser->key)
+        return 0;
+
+    if (parser->state == FIND_MACS_STATE_ENTRY) {
+        if (STRNEQ(parser->key, "domain"))
+            return 0;
+
+        if (!(parser->entry.name = strndup((char *)stringVal, stringLen)))
+            return 0;
+    } else if (parser->state == FIND_MACS_STATE_ENTRY_MACS) {
+        char **macs;
+        if (STRNEQ(parser->key, "macs"))
+            return 0;
+
+        if (!(macs = realloc(parser->entry.macs,
+                             sizeof(char *) * (parser->entry.nmacs + 1))))
+            return 0;
+
+        parser->entry.macs = macs;
+        if (!(macs[parser->entry.nmacs++] = strndup((char *)stringVal, stringLen)))
+            return 0;
+    } else {
+        return 0;
+    }
+    return 1;
+}
+
+
+static int
+findMACsParserMapKey(void *ctx,
+                    const unsigned char *stringVal,
+                    size_t stringLen)
+{
+    findMACsParser *parser = ctx;
+
+    DEBUG("Parse map key state=%d '%.*s'",
+          parser->state, (int)stringLen, (const char *)stringVal);
+
+    free(parser->key);
+    if (!(parser->key = strndup((char *)stringVal, stringLen)))
+        return 0;
+
+    return 1;
+}
+
+
+static int
+findMACsParserStartMap(void *ctx)
+{
+    findMACsParser *parser = ctx;
+
+    DEBUG("Parse start map state=%d", parser->state);
+
+    if (parser->state != FIND_MACS_STATE_LIST)
+        return 0;
+
+    free(parser->key);
+    parser->key = NULL;
+    parser->state = FIND_MACS_STATE_ENTRY;
+
+    return 1;
+}
+
+
+static int
+findMACsParserEndMap(void *ctx)
+{
+    findMACsParser *parser = ctx;
+    size_t i;
+
+    DEBUG("Parse end map state=%d", parser->state);
+
+    if (parser->entry.name == NULL)
+        return 0;
+
+    if (parser->state != FIND_MACS_STATE_ENTRY)
+        return 0;
+
+    if (STREQ(parser->entry.name, parser->name)) {
+        char **macs = realloc(*parser->macs,
+                              sizeof(char *) * ((*parser->nmacs) + parser->entry.nmacs));
+        if (!macs)
+            return 0;
+
+        *parser->macs = macs;
+        for (i = 0; i < parser->entry.nmacs; i++)
+            (*parser->macs)[(*parser->nmacs)++] = parser->entry.macs[i];
+    } else {
+        for (i = 0; i < parser->entry.nmacs; i++)
+            free(parser->entry.macs[i]);
+    }
+    free(parser->entry.macs);
+    parser->entry.macs = NULL;
+    parser->entry.nmacs = 0;
+
+    parser->state = FIND_MACS_STATE_LIST;
+
+    return 1;
+}
+
+
+static int
+findMACsParserStartArray(void *ctx)
+{
+    findMACsParser *parser = ctx;
+
+    DEBUG("Parse start array state=%d", parser->state);
+
+    if (parser->state == FIND_MACS_STATE_START)
+        parser->state = FIND_MACS_STATE_LIST;
+    else if (parser->state == FIND_MACS_STATE_ENTRY)
+        parser->state = FIND_MACS_STATE_ENTRY_MACS;
+    else
+        return 0;
+
+    return 1;
+}
+
+
+static int
+findMACsParserEndArray(void *ctx)
+{
+    findMACsParser *parser = ctx;
+
+    DEBUG("Parse end array state=%d", parser->state);
+
+    if (parser->state == FIND_MACS_STATE_LIST)
+        parser->state = FIND_MACS_STATE_START;
+    else if (parser->state == FIND_MACS_STATE_ENTRY_MACS)
+        parser->state = FIND_MACS_STATE_ENTRY;
+    else
+        return 0;
+
+    return 1;
+}
+
+
+int
+findMACs(const char *file,
+         const char *name,
+         char ***macs,
+         size_t *nmacs)
+{
+    int fd = -1;
+    int ret = -1;
+    const yajl_callbacks parserCallbacks = {
+        NULL, /* null */
+        NULL, /* bool */
+        NULL, /* integer */
+        NULL, /* double */
+        NULL, /* number */
+        findMACsParserString,
+        findMACsParserStartMap,
+        findMACsParserMapKey,
+        findMACsParserEndMap,
+        findMACsParserStartArray,
+        findMACsParserEndArray,
+    };
+    findMACsParser parserState = {
+        .name = name,
+        .macs = macs,
+        .nmacs = nmacs,
+    };
+    yajl_handle parser;
+    char line[1024];
+    size_t i;
+    int rv;
+
+    if ((fd = open(file, O_RDONLY)) < 0) {
+        ERROR("Cannot open %s", file);
+        goto cleanup;
+    }
+
+    parser = yajl_alloc(&parserCallbacks, NULL, &parserState);
+    if (!parser) {
+        ERROR("Unable to create JSON parser");
+        goto cleanup;
+    }
+
+    while (1) {
+        rv = read(fd, line, sizeof(line));
+        if (rv < 0)
+            goto cleanup;
+        if (rv == 0)
+            break;
+
+        if (yajl_parse(parser, (const unsigned char *)line, rv)  !=
+            yajl_status_ok) {
+            ERROR("Parse failed %s",
+                  yajl_get_error(parser, 1,
+                                 (const unsigned char*)line, rv));
+            goto cleanup;
+        }
+    }
+
+    if (yajl_complete_parse(parser) != yajl_status_ok) {
+        ERROR("Parse failed %s",
+              yajl_get_error(parser, 1, NULL, 0));
+        goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+    if (ret != 0) {
+        for (i = 0; i < *nmacs; i++) {
+            char *mac = (*macs)[i];
+            free(mac);
+        }
+        free(*macs);
+        *macs = NULL;
+        *nmacs = 0;
+    }
+    for (i = 0; i < parserState.entry.nmacs; i++)
+        free(parserState.entry.macs[i]);
+    free(parserState.entry.macs);
+    free(parserState.entry.name);
+    free(parserState.key);
+    if (fd != -1)
+        close(fd);
+    return ret;
+}
diff --git a/tools/nss/libvirt_nss_macs.h b/tools/nss/libvirt_nss_macs.h
new file mode 100644
index 0000000000..c504a8cf1f
--- /dev/null
+++ b/tools/nss/libvirt_nss_macs.h
@@ -0,0 +1,27 @@
+/*
+ * libvirt_nss_macs.h: Name Service Switch plugin MAC file parser
+ *
+ * Copyright (C) 2019 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+int
+findMACs(const char *file,
+         const char *name,
+         char ***macs,
+         size_t *nmacs);
-- 
2.21.0


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