[PATCH 02/31] lib: Add resolv_wrapper version 1.0.0.
Andreas Schneider
asn at samba.org
Wed Dec 3 07:44:58 MST 2014
Signed-off-by: Andreas Schneider <asn at samba.org>
---
lib/resolv_wrapper/resolv_wrapper.c | 1377 +++++++++++++++++++++++++++++++++++
lib/resolv_wrapper/wscript | 94 +++
wscript | 1 +
wscript_build | 1 +
4 files changed, 1473 insertions(+)
create mode 100644 lib/resolv_wrapper/resolv_wrapper.c
create mode 100644 lib/resolv_wrapper/wscript
diff --git a/lib/resolv_wrapper/resolv_wrapper.c b/lib/resolv_wrapper/resolv_wrapper.c
new file mode 100644
index 0000000..35f426d
--- /dev/null
+++ b/lib/resolv_wrapper/resolv_wrapper.c
@@ -0,0 +1,1377 @@
+/*
+ * Copyright (c) 2014 Andreas Schneider <asn at samba.org>
+ * Copyright (c) 2014 Jakub Hrozek <jakub.hrozek at gmail.com>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the author nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include <errno.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/types.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+
+#include <resolv.h>
+
+/* GCC has printf type attribute check. */
+#ifdef HAVE_ATTRIBUTE_PRINTF_FORMAT
+#define PRINTF_ATTRIBUTE(a,b) __attribute__ ((__format__ (__printf__, a, b)))
+#else
+#define PRINTF_ATTRIBUTE(a,b)
+#endif /* HAVE_ATTRIBUTE_PRINTF_FORMAT */
+
+#ifdef HAVE_DESTRUCTOR_ATTRIBUTE
+#define DESTRUCTOR_ATTRIBUTE __attribute__ ((destructor))
+#else
+#define DESTRUCTOR_ATTRIBUTE
+#endif /* HAVE_DESTRUCTOR_ATTRIBUTE */
+
+#ifndef RWRAP_DEFAULT_FAKE_TTL
+#define RWRAP_DEFAULT_FAKE_TTL 600
+#endif /* RWRAP_DEFAULT_FAKE_TTL */
+
+enum rwrap_dbglvl_e {
+ RWRAP_LOG_ERROR = 0,
+ RWRAP_LOG_WARN,
+ RWRAP_LOG_DEBUG,
+ RWRAP_LOG_TRACE
+};
+
+#ifdef NDEBUG
+# define RWRAP_LOG(...)
+#else /* NDEBUG */
+
+static void rwrap_log(enum rwrap_dbglvl_e dbglvl, const char *func, const char *format, ...) PRINTF_ATTRIBUTE(3, 4);
+# define RWRAP_LOG(dbglvl, ...) rwrap_log((dbglvl), __func__, __VA_ARGS__)
+
+static void rwrap_log(enum rwrap_dbglvl_e dbglvl,
+ const char *func,
+ const char *format, ...)
+{
+ char buffer[1024];
+ va_list va;
+ const char *d;
+ unsigned int lvl = 0;
+ int pid = getpid();
+
+ d = getenv("RESOLV_WRAPPER_DEBUGLEVEL");
+ if (d != NULL) {
+ lvl = atoi(d);
+ }
+
+ va_start(va, format);
+ vsnprintf(buffer, sizeof(buffer), format, va);
+ va_end(va);
+
+ if (lvl >= dbglvl) {
+ switch (dbglvl) {
+ case RWRAP_LOG_ERROR:
+ fprintf(stderr,
+ "RWRAP_ERROR(%d) - %s: %s\n",
+ pid, func, buffer);
+ break;
+ case RWRAP_LOG_WARN:
+ fprintf(stderr,
+ "RWRAP_WARN(%d) - %s: %s\n",
+ pid, func, buffer);
+ break;
+ case RWRAP_LOG_DEBUG:
+ fprintf(stderr,
+ "RWRAP_DEBUG(%d) - %s: %s\n",
+ pid, func, buffer);
+ break;
+ case RWRAP_LOG_TRACE:
+ fprintf(stderr,
+ "RWRAP_TRACE(%d) - %s: %s\n",
+ pid, func, buffer);
+ break;
+ }
+ }
+}
+#endif /* NDEBUG RWRAP_LOG */
+
+#ifndef SAFE_FREE
+#define SAFE_FREE(x) do { if ((x) != NULL) {free(x); (x)=NULL;} } while(0)
+#endif
+
+#define NEXT_KEY(buf, key) do { \
+ (key) = (buf) ? strpbrk((buf), " \t") : NULL; \
+ if ((key) != NULL) { \
+ (key)[0] = '\0'; \
+ (key)++; \
+ } \
+ while ((key) != NULL \
+ && (isblank((int)(key)[0]))) { \
+ (key)++; \
+ } \
+} while(0);
+
+
+/* Prepares a fake header with a single response. Advances header_blob */
+static ssize_t rwrap_fake_header(uint8_t **header_blob, size_t remaining,
+ size_t rdata_size)
+{
+ uint8_t *hb;
+ HEADER *h;
+ int answers;
+
+ /* If rdata_size is zero, the answer is empty */
+ answers = rdata_size > 0 ? 1 : 0;
+
+ if (remaining < NS_HFIXEDSZ) {
+ RWRAP_LOG(RWRAP_LOG_ERROR, "Buffer too small!\n");
+ return -1;
+ }
+
+ hb = *header_blob;
+ memset(hb, 0, NS_HFIXEDSZ);
+
+ h = (HEADER *) hb;
+ h->id = res_randomid(); /* random query ID */
+ h->qr = 1; /* response flag */
+ h->rd = 1; /* recursion desired */
+ h->ra = 1; /* resursion available */
+
+ h->qdcount = htons(1); /* no. of questions */
+ h->ancount = htons(answers); /* no. of answers */
+
+ hb += NS_HFIXEDSZ; /* move past the header */
+ *header_blob = hb;
+
+ return NS_HFIXEDSZ;
+}
+
+static ssize_t rwrap_fake_question(const char *question,
+ uint16_t type,
+ uint8_t **question_ptr,
+ size_t remaining)
+{
+ uint8_t *qb = *question_ptr;
+ int n;
+
+ n = ns_name_compress(question, qb, remaining, NULL, NULL);
+ if (n < 0) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Failed to compress [%s]\n", question);
+ return -1;
+ }
+
+ qb += n;
+ remaining -= n;
+
+ if (remaining < 2 * sizeof(uint16_t)) {
+ RWRAP_LOG(RWRAP_LOG_ERROR, "Buffer too small!\n");
+ return -1;
+ }
+
+ NS_PUT16(type, qb);
+ NS_PUT16(ns_c_in, qb);
+
+ *question_ptr = qb;
+ return n + 2 * sizeof(uint16_t);
+}
+
+static ssize_t rwrap_fake_rdata_common(uint16_t type,
+ size_t rdata_size,
+ const char *key,
+ size_t remaining,
+ uint8_t **rdata_ptr)
+{
+ uint8_t *rd = *rdata_ptr;
+ ssize_t written = 0;
+
+ written = ns_name_compress(key, rd, remaining, NULL, NULL);
+ if (written < 0) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Failed to compress [%s]\n", key);
+ return -1;
+ }
+ rd += written;
+ remaining -= written;
+
+ if (remaining < 3 * sizeof(uint16_t) + sizeof(uint32_t)) {
+ RWRAP_LOG(RWRAP_LOG_ERROR, "Buffer too small\n");
+ return -1;
+ }
+
+ NS_PUT16(type, rd);
+ NS_PUT16(ns_c_in, rd);
+ NS_PUT32(RWRAP_DEFAULT_FAKE_TTL, rd);
+ NS_PUT16(rdata_size, rd);
+
+ if (remaining < rdata_size) {
+ RWRAP_LOG(RWRAP_LOG_ERROR, "Buffer too small\n");
+ return -1;
+ }
+
+ *rdata_ptr = rd;
+ return written + 3 * sizeof(uint16_t) + sizeof(uint32_t);
+}
+
+static ssize_t rwrap_fake_common(uint16_t type,
+ const char *question,
+ size_t rdata_size,
+ uint8_t **answer_ptr,
+ size_t anslen)
+{
+ uint8_t *a = *answer_ptr;
+ ssize_t written;
+ size_t remaining;
+
+ remaining = anslen;
+
+ written = rwrap_fake_header(&a, remaining, rdata_size);
+ if (written < 0) {
+ return -1;
+ }
+ remaining -= written;
+
+ written = rwrap_fake_question(question, type, &a, remaining);
+ if (written < 0) {
+ return -1;
+ }
+ remaining -= written;
+
+ /* rdata_size = 0 denotes an empty answer */
+ if (rdata_size > 0) {
+ written = rwrap_fake_rdata_common(type, rdata_size, question,
+ remaining, &a);
+ if (written < 0) {
+ return -1;
+ }
+ }
+
+ *answer_ptr = a;
+ return written;
+}
+
+static int rwrap_fake_a(const char *key,
+ const char *value,
+ uint8_t *answer_ptr,
+ size_t anslen)
+{
+ uint8_t *a = answer_ptr;
+ struct in_addr a_rec;
+ int rc;
+ int ok;
+
+ if (value == NULL) {
+ RWRAP_LOG(RWRAP_LOG_ERROR, "Malformed record, no value!\n");
+ return -1;
+ }
+
+ rc = rwrap_fake_common(ns_t_a, key, sizeof(a_rec), &a, anslen);
+ if (rc < 0) {
+ return -1;
+ }
+
+ ok = inet_pton(AF_INET, value, &a_rec);
+ if (!ok) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Failed to convert [%s] to binary\n", value);
+ return -1;
+ }
+ memcpy(a, &a_rec, sizeof(struct in_addr));
+
+ return 0;
+}
+
+static int rwrap_fake_aaaa(const char *key,
+ const char *value,
+ uint8_t *answer,
+ size_t anslen)
+{
+ uint8_t *a = answer;
+ struct in6_addr aaaa_rec;
+ int rc;
+ int ok;
+
+ if (value == NULL) {
+ RWRAP_LOG(RWRAP_LOG_ERROR, "Malformed record, no value!\n");
+ return -1;
+ }
+
+ rc = rwrap_fake_common(ns_t_aaaa, key, sizeof(aaaa_rec), &a, anslen);
+ if (rc < 0) {
+ return -1;
+ }
+
+ ok = inet_pton(AF_INET6, value, &aaaa_rec);
+ if (!ok) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Failed to convert [%s] to binary\n", value);
+ return -1;
+ }
+ memcpy(a, &aaaa_rec, sizeof(struct in6_addr));
+
+ return 0;
+}
+
+/*
+ * Priority and weight can be omitted from the hosts file, but need to be part
+ * of the output
+ */
+#define DFL_SRV_PRIO 1
+#define DFL_SRV_WEIGHT 100
+
+static int rwrap_fake_srv(const char *key,
+ const char *value,
+ uint8_t *answer,
+ size_t anslen)
+{
+ uint8_t *a = answer;
+ int rv;
+ size_t rdata_size;
+ char *str_prio;
+ char *str_weight;
+ char *str_port;
+ const char *hostname;
+ unsigned char hostname_compressed[MAXDNAME];
+ ssize_t compressed_len;
+
+ /*
+ * Parse the value into priority, weight, port and hostname
+ * and check the validity.
+ */
+ hostname = value;
+ NEXT_KEY(hostname, str_port);
+ NEXT_KEY(str_port, str_prio);
+ NEXT_KEY(str_prio, str_weight);
+ if (str_port == NULL || hostname == NULL) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Malformed SRV entry [%s]\n", value);
+ return -1;
+ }
+ rdata_size = 3 * sizeof(uint16_t);
+
+ /* Prepare the data to write */
+ compressed_len = ns_name_compress(hostname,
+ hostname_compressed, MAXDNAME,
+ NULL, NULL);
+ if (compressed_len < 0) {
+ return -1;
+ }
+ rdata_size += compressed_len;
+
+ rv = rwrap_fake_common(ns_t_srv, key, rdata_size, &a, anslen);
+ if (rv < 0) {
+ return -1;
+ }
+
+ if (str_prio) {
+ NS_PUT16(atoi(str_prio), a);
+ } else {
+ NS_PUT16(DFL_SRV_PRIO, a);
+ }
+ if (str_weight) {
+ NS_PUT16(atoi(str_weight), a);
+ } else {
+ NS_PUT16(DFL_SRV_WEIGHT, a);
+ }
+ NS_PUT16(atoi(str_port), a);
+ memcpy(a, hostname_compressed, compressed_len);
+
+ return 0;
+}
+
+static int rwrap_fake_soa(const char *key,
+ const char *value,
+ uint8_t *answer,
+ size_t anslen)
+{
+ uint8_t *a = answer;
+ int rv;
+ const char *nameserver;
+ char *mailbox;
+ char *str_serial;
+ char *str_refresh;
+ char *str_retry;
+ char *str_expire;
+ char *str_minimum;
+ size_t rdata_size;
+ unsigned char nameser_compressed[MAXDNAME];
+ ssize_t compressed_ns_len;
+ unsigned char mailbox_compressed[MAXDNAME];
+ ssize_t compressed_mb_len;
+
+ /*
+ * parse the value into nameserver, mailbox, serial, refresh,
+ * retry, expire, minimum and check the validity
+ */
+ nameserver = value;
+ NEXT_KEY(nameserver, mailbox);
+ NEXT_KEY(mailbox, str_serial);
+ NEXT_KEY(str_serial, str_refresh);
+ NEXT_KEY(str_refresh, str_retry);
+ NEXT_KEY(str_retry, str_expire);
+ NEXT_KEY(str_expire, str_minimum);
+ if (nameserver == NULL || mailbox == NULL || str_serial == NULL ||
+ str_refresh == NULL || str_retry == NULL || str_expire == NULL ||
+ str_minimum == NULL)
+ {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Malformed SOA entry [%s]\n", value);
+ return -1;
+ }
+ rdata_size = 5 * sizeof(uint16_t);
+
+ compressed_ns_len = ns_name_compress(nameserver, nameser_compressed,
+ MAXDNAME, NULL, NULL);
+ if (compressed_ns_len < 0) {
+ return -1;
+ }
+ rdata_size += compressed_ns_len;
+
+ compressed_mb_len = ns_name_compress(mailbox, mailbox_compressed,
+ MAXDNAME, NULL, NULL);
+ if (compressed_mb_len < 0) {
+ return -1;
+ }
+ rdata_size += compressed_mb_len;
+
+ rv = rwrap_fake_common(ns_t_soa, key, rdata_size, &a, anslen);
+ if (rv < 0) {
+ return -1;
+ }
+
+ memcpy(a, nameser_compressed, compressed_ns_len);
+ a += compressed_ns_len;
+ memcpy(a, mailbox_compressed, compressed_mb_len);
+ a += compressed_mb_len;
+ NS_PUT32(atoi(str_serial), a);
+ NS_PUT32(atoi(str_refresh), a);
+ NS_PUT32(atoi(str_retry), a);
+ NS_PUT32(atoi(str_expire), a);
+ NS_PUT32(atoi(str_minimum), a);
+
+ return 0;
+}
+
+static int rwrap_fake_cname(const char *key,
+ const char *value,
+ uint8_t *answer,
+ size_t anslen)
+{
+ uint8_t *a = answer;
+ int rv;
+ unsigned char hostname_compressed[MAXDNAME];
+ ssize_t rdata_size;
+
+ if (value == NULL) {
+ RWRAP_LOG(RWRAP_LOG_ERROR, "Malformed record, no value!\n");
+ return -1;
+ }
+
+ /* Prepare the data to write */
+ rdata_size = ns_name_compress(value,
+ hostname_compressed, MAXDNAME,
+ NULL, NULL);
+ if (rdata_size < 0) {
+ return -1;
+ }
+
+ rv = rwrap_fake_common(ns_t_cname, key, rdata_size, &a, anslen);
+ if (rv < 0) {
+ return -1;
+ }
+
+ memcpy(a, hostname_compressed, rdata_size);
+
+ return 0;
+}
+
+static int rwrap_fake_empty_query(const char *key,
+ uint16_t type,
+ uint8_t *answer,
+ size_t anslen)
+{
+ int rc;
+
+ rc = rwrap_fake_common(type, key, 0, &answer, anslen);
+ if (rc < 0) {
+ return -1;
+ }
+
+ return 0;
+}
+
+#define RESOLV_MATCH(line, name) \
+ (strncmp(line, name, sizeof(name) - 1) == 0 && \
+ (line[sizeof(name) - 1] == ' ' || \
+ line[sizeof(name) - 1] == '\t'))
+
+#define TYPE_MATCH(type, ns_type, rec_type, str_type, key, query) \
+ ((type) == (ns_type) && \
+ (strncmp((rec_type), (str_type), sizeof(str_type)) == 0) && \
+ (strcmp(key, query)) == 0)
+
+
+/* Reads in a file in the following format:
+ * TYPE RDATA
+ *
+ * Malformed entried are silently skipped.
+ * Allocates answer buffer of size anslen that has to be freed after use.
+ */
+static int rwrap_res_fake_hosts(const char *hostfile,
+ const char *query,
+ int type,
+ unsigned char *answer,
+ size_t anslen)
+{
+ FILE *fp = NULL;
+ char buf[BUFSIZ];
+ int rc = ENOENT;
+ char *key = NULL;
+ char *value = NULL;
+
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ "Searching in fake hosts file %s\n", hostfile);
+
+ fp = fopen(hostfile, "r");
+ if (fp == NULL) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Opening %s failed: %s",
+ hostfile, strerror(errno));
+ return -1;
+ }
+
+ while (fgets(buf, sizeof(buf), fp) != NULL) {
+ char *rec_type;
+ char *q;
+
+ rec_type = buf;
+ key = value = NULL;
+
+ NEXT_KEY(rec_type, key);
+ NEXT_KEY(key, value);
+
+ q = value;
+ while(q[0] != '\n' && q[0] != '\0') {
+ q++;
+ }
+ q[0] = '\0';
+
+ if (key == NULL || value == NULL) {
+ RWRAP_LOG(RWRAP_LOG_WARN,
+ "Malformed line: not enough parts, use \"rec_type key data\n"
+ "For example \"A cwrap.org 10.10.10.10\"");
+ continue;
+ }
+
+ if (TYPE_MATCH(type, ns_t_a, rec_type, "A", key, query)) {
+ rc = rwrap_fake_a(key, value, answer, anslen);
+ break;
+ } else if (TYPE_MATCH(type, ns_t_aaaa,
+ rec_type, "AAAA", key, query)) {
+ rc = rwrap_fake_aaaa(key, value, answer, anslen);
+ break;
+ } else if (TYPE_MATCH(type, ns_t_srv,
+ rec_type, "SRV", key, query)) {
+ rc = rwrap_fake_srv(key, value, answer, anslen);
+ break;
+ } else if (TYPE_MATCH(type, ns_t_soa,
+ rec_type, "SOA", key, query)) {
+ rc = rwrap_fake_soa(key, value, answer, anslen);
+ break;
+ } else if (TYPE_MATCH(type, ns_t_cname,
+ rec_type, "CNAME", key, query)) {
+ rc = rwrap_fake_cname(key, value, answer, anslen);
+ break;
+ }
+ }
+
+ switch (rc) {
+ case 0:
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ "Successfully faked answer for [%s]\n", query);
+ break;
+ case -1:
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Error faking answer for [%s]\n", query);
+ break;
+ case ENOENT:
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ "Record for [%s] not found\n", query);
+ rc = rwrap_fake_empty_query(key, type, answer, anslen);
+ break;
+ }
+
+ fclose(fp);
+ return rc;
+}
+
+/*********************************************************
+ * RWRAP LOADING LIBC FUNCTIONS
+ *********************************************************/
+
+#include <dlfcn.h>
+
+struct rwrap_libc_fns {
+ int (*libc_res_init)(void);
+ int (*libc___res_init)(void);
+ int (*libc_res_ninit)(struct __res_state *state);
+ int (*libc___res_ninit)(struct __res_state *state);
+ void (*libc_res_nclose)(struct __res_state *state);
+ void (*libc___res_nclose)(struct __res_state *state);
+ void (*libc_res_close)(void);
+ void (*libc___res_close)(void);
+ int (*libc_res_nquery)(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen);
+ int (*libc___res_nquery)(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen);
+ int (*libc_res_nsearch)(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen);
+ int (*libc___res_nsearch)(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen);
+};
+
+struct rwrap {
+ void *libc_handle;
+ void *libresolv_handle;
+
+ bool initialised;
+ bool enabled;
+
+ char *socket_dir;
+
+ struct rwrap_libc_fns fns;
+};
+
+static struct rwrap rwrap;
+
+enum rwrap_lib {
+ RWRAP_LIBC,
+ RWRAP_LIBRESOLV
+};
+
+#ifndef NDEBUG
+static const char *rwrap_str_lib(enum rwrap_lib lib)
+{
+ switch (lib) {
+ case RWRAP_LIBC:
+ return "libc";
+ case RWRAP_LIBRESOLV:
+ return "libresolv";
+ }
+
+ /* Compiler would warn us about unhandled enum value if we get here */
+ return "unknown";
+}
+#endif
+
+static void *rwrap_load_lib_handle(enum rwrap_lib lib)
+{
+ int flags = RTLD_LAZY;
+ void *handle = NULL;
+ int i;
+
+#ifdef RTLD_DEEPBIND
+ flags |= RTLD_DEEPBIND;
+#endif
+
+ switch (lib) {
+ case RWRAP_LIBRESOLV:
+#ifdef HAVE_LIBRESOLV
+ handle = rwrap.libresolv_handle;
+ if (handle == NULL) {
+ for (i = 10; i >= 0; i--) {
+ char soname[256] = {0};
+
+ snprintf(soname, sizeof(soname), "libresolv.so.%d", i);
+ handle = dlopen(soname, flags);
+ if (handle != NULL) {
+ break;
+ }
+ }
+
+ rwrap.libresolv_handle = handle;
+ }
+ break;
+#endif
+ /* FALL TROUGH */
+ case RWRAP_LIBC:
+ handle = rwrap.libc_handle;
+#ifdef LIBC_SO
+ if (handle == NULL) {
+ handle = dlopen(LIBC_SO, flags);
+
+ rwrap.libc_handle = handle;
+ }
+#endif
+ if (handle == NULL) {
+ for (i = 10; i >= 0; i--) {
+ char soname[256] = {0};
+
+ snprintf(soname, sizeof(soname), "libc.so.%d", i);
+ handle = dlopen(soname, flags);
+ if (handle != NULL) {
+ break;
+ }
+ }
+
+ rwrap.libc_handle = handle;
+ }
+ break;
+ }
+
+ if (handle == NULL) {
+#ifdef RTLD_NEXT
+ handle = rwrap.libc_handle = rwrap.libresolv_handle = RTLD_NEXT;
+#else
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Failed to dlopen library: %s\n",
+ dlerror());
+ exit(-1);
+#endif
+ }
+
+ return handle;
+}
+
+static void *_rwrap_load_lib_function(enum rwrap_lib lib, const char *fn_name)
+{
+ void *handle;
+ void *func;
+
+ handle = rwrap_load_lib_handle(lib);
+
+ func = dlsym(handle, fn_name);
+ if (func == NULL) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Failed to find %s: %s\n",
+ fn_name, dlerror());
+ exit(-1);
+ }
+
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ "Loaded %s from %s",
+ fn_name, rwrap_str_lib(lib));
+ return func;
+}
+
+#define rwrap_load_lib_function(lib, fn_name) \
+ if (rwrap.fns.libc_##fn_name == NULL) { \
+ *(void **) (&rwrap.fns.libc_##fn_name) = \
+ _rwrap_load_lib_function(lib, #fn_name); \
+ }
+
+/*
+ * IMPORTANT
+ *
+ * Functions especially from libc need to be loaded individually, you can't load
+ * all at once or gdb will segfault at startup. The same applies to valgrind and
+ * has probably something todo with with the linker.
+ * So we need load each function at the point it is called the first time.
+ */
+#if 0
+static int libc_res_init(void)
+{
+#if defined(HAVE_RES_INIT)
+ rwrap_load_lib_function(RWRAP_LIBRESOLV, res_init);
+
+ return rwrap.fns.libc_res_init();
+#elif defined(HAVE___RES_INIT)
+ rwrap_load_lib_function(RWRAP_LIBRESOLV, __res_init);
+
+ return rwrap.fns.libc___res_init();
+#endif
+}
+#endif
+
+static int libc_res_ninit(struct __res_state *state)
+{
+#if defined(HAVE_RES_NINIT)
+
+#if defined(HAVE_RES_NINIT_IN_LIBRESOLV)
+ rwrap_load_lib_function(RWRAP_LIBRESOLV, res_ninit);
+#else /* HAVE_RES_NINIT_IN_LIBRESOLV */
+ rwrap_load_lib_function(RWRAP_LIBC, res_ninit);
+#endif /* HAVE_RES_NINIT_IN_LIBRESOLV */
+
+ return rwrap.fns.libc_res_ninit(state);
+#elif defined(HAVE___RES_NINIT)
+ rwrap_load_lib_function(RWRAP_LIBC, __res_ninit);
+
+ return rwrap.fns.libc___res_ninit(state);
+#else
+#error "No res_ninit function"
+#endif
+}
+
+static void libc_res_nclose(struct __res_state *state)
+{
+#if defined(HAVE_RES_NCLOSE)
+
+#if defined(HAVE_RES_NCLOSE_IN_LIBRESOLV)
+ rwrap_load_lib_function(RWRAP_LIBRESOLV, res_nclose);
+#else /* HAVE_RES_NCLOSE_IN_LIBRESOLV */
+ rwrap_load_lib_function(RWRAP_LIBC, res_nclose);
+#endif /* HAVE_RES_NCLOSE_IN_LIBRESOLV */
+
+ rwrap.fns.libc_res_nclose(state);
+#elif defined(HAVE___RES_NCLOSE)
+ rwrap_load_lib_function(RWRAP_LIBC, __res_nclose);
+
+ rwrap.fns.libc___res_nclose(state);
+#else
+#error "No res_nclose function"
+#endif
+}
+
+static int libc_res_nquery(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+{
+#if defined(HAVE_RES_NQUERY)
+ rwrap_load_lib_function(RWRAP_LIBRESOLV, res_nquery);
+
+ return rwrap.fns.libc_res_nquery(state,
+ dname,
+ class,
+ type,
+ answer,
+ anslen);
+#elif defined(HAVE___RES_NQUERY)
+ rwrap_load_lib_function(RWRAP_LIBRESOLV, __res_nquery);
+
+ return rwrap.fns.libc___res_nquery(state,
+ dname,
+ class,
+ type,
+ answer,
+ anslen);
+#else
+#error "No res_nquery function"
+#endif
+}
+
+static int libc_res_nsearch(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+{
+#if defined(HAVE_RES_NSEARCH)
+ rwrap_load_lib_function(RWRAP_LIBRESOLV, res_nsearch);
+
+ return rwrap.fns.libc_res_nsearch(state,
+ dname,
+ class,
+ type,
+ answer,
+ anslen);
+#elif defined(HAVE___RES_NSEARCH)
+ rwrap_load_lib_function(RWRAP_LIBRESOLV, __res_nsearch);
+
+ return rwrap.fns.libc___res_nsearch(state,
+ dname,
+ class,
+ type,
+ answer,
+ anslen);
+#else
+#error "No res_nsearch function"
+#endif
+}
+
+/****************************************************************************
+ * RES_HELPER
+ ***************************************************************************/
+
+static int rwrap_parse_resolv_conf(struct __res_state *state,
+ const char *resolv_conf)
+{
+ FILE *fp;
+ char buf[BUFSIZ];
+ int nserv = 0;
+
+ fp = fopen(resolv_conf, "r");
+ if (fp == NULL) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Opening %s failed: %s",
+ resolv_conf, strerror(errno));
+ return -1;
+ }
+
+ while(fgets(buf, sizeof(buf), fp) != NULL) {
+ char *p;
+
+ /* Ignore comments */
+ if (buf[0] == '#' || buf[0] == ';') {
+ continue;
+ }
+
+ if (RESOLV_MATCH(buf, "nameserver") && nserv < MAXNS) {
+ struct in_addr a;
+ char *q;
+ int ok;
+
+ p = buf + strlen("nameserver");
+
+ /* Skip spaces and tabs */
+ while(isblank((int)p[0])) {
+ p++;
+ }
+
+ q = p;
+ while(q[0] != '\n' && q[0] != '\0') {
+ q++;
+ }
+ q[0] = '\0';
+
+ ok = inet_pton(AF_INET, p, &a);
+ if (ok) {
+ state->nsaddr_list[state->nscount] = (struct sockaddr_in) {
+ .sin_family = AF_INET,
+ .sin_addr = a,
+ .sin_port = htons(53),
+ .sin_zero = { 0 },
+ };
+
+ state->nscount++;
+ nserv++;
+ } else {
+#ifdef HAVE_RESOLV_IPV6_NSADDRS
+ /* IPv6 */
+ struct in6_addr a6;
+ ok = inet_pton(AF_INET6, p, &a6);
+ if (ok) {
+ struct sockaddr_in6 *sa6;
+
+ sa6 = malloc(sizeof(*sa6));
+ if (sa6 == NULL) {
+ fclose(fp);
+ return -1;
+ }
+
+ sa6->sin6_family = AF_INET6;
+ sa6->sin6_port = htons(53);
+ sa6->sin6_flowinfo = 0;
+ sa6->sin6_addr = a6;
+
+ state->_u._ext.nsaddrs[state->_u._ext.nscount] = sa6;
+ state->_u._ext.nssocks[state->_u._ext.nscount] = -1;
+ state->_u._ext.nsmap[state->_u._ext.nscount] = MAXNS + 1;
+
+ state->_u._ext.nscount++;
+ nserv++;
+ } else {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Malformed DNS server");
+ continue;
+ }
+#else /* !HAVE_RESOLV_IPV6_NSADDRS */
+ /*
+ * BSD uses an opaque structure to store the
+ * IPv6 addresses. So we can not simply store
+ * these addresses the same way as above.
+ */
+ RWRAP_LOG(RWRAP_LOG_WARN,
+ "resolve_wrapper does not support "
+ "IPv6 on this platform");
+ continue;
+#endif
+ }
+ continue;
+ } /* TODO: match other keywords */
+ }
+
+ if (ferror(fp)) {
+ RWRAP_LOG(RWRAP_LOG_ERROR,
+ "Reading from %s failed",
+ resolv_conf);
+ fclose(fp);
+ return -1;
+ }
+
+ fclose(fp);
+ return 0;
+}
+
+/****************************************************************************
+ * RES_NINIT
+ ***************************************************************************/
+
+static int rwrap_res_ninit(struct __res_state *state)
+{
+ int rc;
+
+ rc = libc_res_ninit(state);
+ if (rc == 0) {
+ const char *resolv_conf = getenv("RESOLV_WRAPPER_CONF");
+
+ if (resolv_conf != NULL) {
+ uint16_t i;
+
+ (void)i; /* maybe unused */
+
+ /* Delete name servers */
+ state->nscount = 0;
+ memset(state->nsaddr_list, 0, sizeof(state->nsaddr_list));
+
+ state->_u._ext.nscount = 0;
+#ifdef HAVE_RESOLV_IPV6_NSADDRS
+ for (i = 0; i < state->_u._ext.nscount; i++) {
+ SAFE_FREE(state->_u._ext.nsaddrs[i]);
+ }
+#endif
+
+ rc = rwrap_parse_resolv_conf(state, resolv_conf);
+ }
+ }
+
+ return rc;
+}
+
+#if defined(HAVE_RES_NINIT)
+int res_ninit(struct __res_state *state)
+#elif defined(HAVE___RES_NINIT)
+int __res_ninit(struct __res_state *state)
+#endif
+{
+ return rwrap_res_ninit(state);
+}
+
+/****************************************************************************
+ * RES_INIT
+ ***************************************************************************/
+
+static struct __res_state rwrap_res_state;
+
+static int rwrap_res_init(void)
+{
+ int rc;
+
+ rc = rwrap_res_ninit(&rwrap_res_state);
+
+ return rc;
+}
+
+#if defined(HAVE_RES_INIT)
+int res_init(void)
+#elif defined(HAVE___RES_INIT)
+int __res_init(void)
+#endif
+{
+ return rwrap_res_init();
+}
+
+/****************************************************************************
+ * RES_NCLOSE
+ ***************************************************************************/
+
+static void rwrap_res_nclose(struct __res_state *state)
+{
+#ifdef HAVE_RESOLV_IPV6_NSADDRS
+ int i;
+#endif
+
+ libc_res_nclose(state);
+
+#ifdef HAVE_RESOLV_IPV6_NSADDRS
+ if (state != NULL) {
+ for (i = 0; i < state->_u._ext.nscount; i++) {
+ SAFE_FREE(state->_u._ext.nsaddrs[i]);
+ }
+ }
+#endif
+}
+
+#if defined(HAVE_RES_NCLOSE)
+void res_nclose(struct __res_state *state)
+#elif defined(HAVE___RES_NCLOSE)
+void __res_nclose(struct __res_state *state)
+#endif
+{
+ rwrap_res_nclose(state);
+}
+
+/****************************************************************************
+ * RES_CLOSE
+ ***************************************************************************/
+
+static void rwrap_res_close(void)
+{
+ rwrap_res_nclose(&rwrap_res_state);
+}
+
+#if defined(HAVE_RES_CLOSE)
+void res_close(void)
+#elif defined(HAVE___RES_CLOSE)
+void __res_close(void)
+#endif
+{
+ rwrap_res_close();
+}
+
+/****************************************************************************
+ * RES_NQUERY
+ ***************************************************************************/
+
+static int rwrap_res_nquery(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+{
+ int rc;
+ const char *fake_hosts;
+#ifndef NDEBUG
+ int i;
+#endif
+
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ "Resolve the domain name [%s] - class=%d, type=%d",
+ dname, class, type);
+#ifndef NDEBUG
+ for (i = 0; i < state->nscount; i++) {
+ char ip[INET6_ADDRSTRLEN];
+
+ inet_ntop(AF_INET, &state->nsaddr_list[i].sin_addr, ip, sizeof(ip));
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ " nameserver: %s",
+ ip);
+ }
+#endif
+
+ fake_hosts = getenv("RESOLV_WRAPPER_HOSTS");
+ if (fake_hosts != NULL) {
+ rc = rwrap_res_fake_hosts(fake_hosts, dname, type, answer, anslen);
+ } else {
+ rc = libc_res_nquery(state, dname, class, type, answer, anslen);
+ }
+
+
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ "The returned response length is: %d",
+ rc);
+
+ return rc;
+}
+
+#if defined(HAVE_RES_NQUERY)
+int res_nquery(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+#elif defined(HAVE___RES_NQUERY)
+int __res_nquery(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+#endif
+{
+ return rwrap_res_nquery(state, dname, class, type, answer, anslen);
+}
+
+/****************************************************************************
+ * RES_QUERY
+ ***************************************************************************/
+
+static int rwrap_res_query(const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+{
+ int rc;
+
+ rc = rwrap_res_ninit(&rwrap_res_state);
+ if (rc != 0) {
+ return rc;
+ }
+
+ rc = rwrap_res_nquery(&rwrap_res_state,
+ dname,
+ class,
+ type,
+ answer,
+ anslen);
+
+ return rc;
+}
+
+#if defined(HAVE_RES_QUERY)
+int res_query(const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+#elif defined(HAVE___RES_QUERY)
+int __res_query(const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+#endif
+{
+ return rwrap_res_query(dname, class, type, answer, anslen);
+}
+
+/****************************************************************************
+ * RES_NSEARCH
+ ***************************************************************************/
+
+static int rwrap_res_nsearch(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+{
+ int rc;
+ const char *fake_hosts;
+#ifndef NDEBUG
+ int i;
+#endif
+
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ "Resolve the domain name [%s] - class=%d, type=%d",
+ dname, class, type);
+#ifndef NDEBUG
+ for (i = 0; i < state->nscount; i++) {
+ char ip[INET6_ADDRSTRLEN];
+
+ inet_ntop(AF_INET, &state->nsaddr_list[i].sin_addr, ip, sizeof(ip));
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ " nameserver: %s",
+ ip);
+ }
+#endif
+
+ fake_hosts = getenv("RESOLV_WRAPPER_HOSTS");
+ if (fake_hosts != NULL) {
+ rc = rwrap_res_fake_hosts(fake_hosts, dname, type, answer, anslen);
+ } else {
+ rc = libc_res_nsearch(state, dname, class, type, answer, anslen);
+ }
+
+ RWRAP_LOG(RWRAP_LOG_TRACE,
+ "The returned response length is: %d",
+ rc);
+
+ return rc;
+}
+
+#if defined(HAVE_RES_NSEARCH)
+int res_nsearch(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+#elif defined(HAVE___RES_NSEARCH)
+int __res_nsearch(struct __res_state *state,
+ const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+#endif
+{
+ return rwrap_res_nsearch(state, dname, class, type, answer, anslen);
+}
+
+/****************************************************************************
+ * RES_QUERY
+ ***************************************************************************/
+
+static int rwrap_res_search(const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+{
+ int rc;
+
+ rc = rwrap_res_ninit(&rwrap_res_state);
+ if (rc != 0) {
+ return rc;
+ }
+
+ rc = rwrap_res_nsearch(&rwrap_res_state,
+ dname,
+ class,
+ type,
+ answer,
+ anslen);
+
+ return rc;
+}
+
+#if defined(HAVE_RES_SEARCH)
+int res_search(const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+#elif defined(HAVE___RES_SEARCH)
+int __res_search(const char *dname,
+ int class,
+ int type,
+ unsigned char *answer,
+ int anslen)
+#endif
+{
+ return rwrap_res_search(dname, class, type, answer, anslen);
+}
diff --git a/lib/resolv_wrapper/wscript b/lib/resolv_wrapper/wscript
new file mode 100644
index 0000000..d72ec18
--- /dev/null
+++ b/lib/resolv_wrapper/wscript
@@ -0,0 +1,94 @@
+#!/usr/bin/env python
+
+import os
+
+VERSION="1.0.0"
+
+def configure(conf):
+ if conf.CHECK_BUNDLED_SYSTEM('resolv_wrapper', minversion=VERSION, set_target=False):
+ conf.DEFINE('USING_SYSTEM_RESOLV_WRAPPER', 1)
+ libresolv_wrapper_so_path = 'libresolv_wrapper.so'
+ else:
+ # check HAVE_GCC_THREAD_LOCAL_STORAGE
+ conf.CHECK_CODE('''
+ __thread int tls;
+
+ int main(void) {
+ return 0;
+ }
+ ''',
+ 'HAVE_GCC_THREAD_LOCAL_STORAGE',
+ addmain=False,
+ msg='Checking for thread local storage')
+
+ # check HAVE_DESTRUCTOR_ATTRIBUTE
+ conf.CHECK_CODE('''
+ void test_destructor_attribute(void) __attribute__ ((destructor));
+
+ void test_destructor_attribute(void)
+ {
+ return;
+ }
+
+ int main(void) {
+ return 0;
+ }
+ ''',
+ 'HAVE_DESTRUCTOR_ATTRIBUTE',
+ addmain=False,
+ msg='Checking for library destructor support')
+
+ # check HAVE_FUNCTION_ATTRIBUTE_FORMAT
+ conf.CHECK_CODE('''
+ void log_fn(const char *format, ...) __attribute__ ((format (printf, 1, 2)));
+
+ int main(void) {
+ return 0;
+ }
+ ''',
+ 'HAVE_FUNCTION_ATTRIBUTE_FORMAT',
+ addmain=False,
+ msg='Checking for printf format validation support')
+
+ conf.CHECK_HEADERS('resolv.h')
+
+ conf.CHECK_STRUCTURE_MEMBER('struct _res_state',
+ '_u._ext.nsaddrs',
+ headers='resolv.h',
+ define='HAVE_RESOLV_IPV6_NSADDRS')
+
+ conf.CHECK_FUNCS_IN('res_ninit', 'resolv')
+ if conf.CONFIG_SET('HAVE_RES_NINIT'):
+ conf.DEFINE('HAVE_RES_NINIT_IN_LIBRESOLV', 1)
+
+ conf.CHECK_FUNCS_IN('res_nclose', 'resolv')
+ if conf.CONFIG_SET('HAVE_RES_NCLOSE'):
+ conf.DEFINE('HAVE_RES_NCLOSE_IN_LIBRESOLV', 1)
+
+ conf.CHECK_FUNCS_IN('res_init __res_init', 'resolv', checklibc=True)
+ conf.CHECK_FUNCS_IN('res_ninit __res_ninit', 'resolv', checklibc=True)
+ conf.CHECK_FUNCS_IN('res_close __res_close', 'resolv', checklibc=True)
+ conf.CHECK_FUNCS_IN('res_nclose __res_nclose', 'resolv', checklibc=True)
+ conf.CHECK_FUNCS_IN('res_query __res_query', 'resolv', checklibc=True)
+ conf.CHECK_FUNCS_IN('res_nquery __res_nquery', 'resolv', checklibc=True)
+ conf.CHECK_FUNCS_IN('res_search __res_search', 'resolv', checklibc=True)
+ conf.CHECK_FUNCS_IN('res_nsearch __res_nsearch', 'resolv', checklibc=True)
+
+ # Create full path to resolv_wrapper
+ srcdir = os.path.realpath(conf.srcdir)
+ libresolv_wrapper_so_path = srcdir + '/bin/default/lib/resolv_wrapper/libresolv-wrapper.so'
+
+ conf.DEFINE('LIBRESOLV_WRAPPER_SO_PATH', libresolv_wrapper_so_path)
+ conf.DEFINE('RESOLV_WRAPPER', 1)
+
+def build(bld):
+ if bld.CONFIG_SET("HAVE_RESOLV_H") and not bld.CONFIG_SET("USING_SYSTEM_RESOLV_WRAPPER"):
+ # We need to do it this way or the library wont work.
+ # Using private_library=True will add symbol version which
+ # breaks preloading!
+ bld.SAMBA_LIBRARY('resolv_wrapper',
+ source='resolv_wrapper.c',
+ cflags='-DNDEBUG',
+ deps='dl resolv',
+ install=False,
+ realname='libresolv-wrapper.so')
diff --git a/wscript b/wscript
index 872177e..d851885 100644
--- a/wscript
+++ b/wscript
@@ -158,6 +158,7 @@ def configure(conf):
conf.RECURSE('source4/auth')
conf.RECURSE('lib/nss_wrapper')
conf.RECURSE('nsswitch')
+ conf.RECURSE('lib/resolv_wrapper')
conf.RECURSE('lib/socket_wrapper')
conf.RECURSE('lib/uid_wrapper')
conf.RECURSE('lib/subunit/c')
diff --git a/wscript_build b/wscript_build
index e74841e..fc41974 100644
--- a/wscript_build
+++ b/wscript_build
@@ -71,6 +71,7 @@ bld.RECURSE('source4/lib/events')
bld.RECURSE('source4/lib/cmdline')
bld.RECURSE('source4/lib/http')
bld.RECURSE('lib/socket_wrapper')
+bld.RECURSE('lib/resolv_wrapper')
bld.RECURSE('lib/nss_wrapper')
bld.RECURSE('lib/uid_wrapper')
if bld.CHECK_FOR_THIRD_PARTY():
--
2.1.3
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