nscd: add cache dumper

nscd/Makefile

@@ -36,7 +36,7 @@ nscd-modules := nscd connections pwdcache getpwnam_r getpwuid_r grpcache \
 		getsrvbynm_r getsrvbypt_r servicescache \
 		dbg_log nscd_conf nscd_stat cache mem nscd_setup_thread \
 		xmalloc xstrdup aicache initgrcache gai res_hconf \
-		netgroupcache
+		netgroupcache cachedumper
 
 ifeq ($(build-nscd)$(have-thread-library),yesyes)
 

nscd/cachedumper.c

@@ -0,0 +1,373 @@
+/* Copyright (c) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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; version 2 of the License, or
+   (at your option) any later version.
+
+   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 <https://www.gnu.org/licenses/>.  */
+
+/* cachedumper - dump a human-readable representation of a cache file.  */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <libintl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <arpa/inet.h>
+#include <getopt.h>
+
+#include "nscd.h"
+#include "dbg_log.h"
+
+static void *the_cache;
+
+#define NO_REF ((ref_t)-1)
+
+/* Given a chunk of raw data CP of length LEN, print it in a hopefully
+   user-readable format, including colorizing non-readable characters.
+   STR prefixes it, if non-NULL.  If LEN is -1, CP is
+   NUL-terminated.  */
+unsigned char *
+data_string (unsigned char *cp, const char *str, int len)
+{
+  int oops = 0;
+  unsigned char *cpe = cp + len;
+  printf ("%s", str);
+  while (len == -1 || cp < cpe)
+    {
+      if (isgraph (*cp))
+	putchar (*cp);
+      else
+	printf ("\033[%dm<%02x>\033[0m", *cp % 6 + 31, *cp);
+      if (len == -1 && *cp == 0)
+	return cp + 1;
+
+      ++cp;
+      if (++oops > 1000)
+	break;
+    }
+  return cp;
+}
+
+void
+nscd_print_cache (const char *name)
+{
+  struct stat st;
+  int fd;
+  int i;
+
+  if (stat (name, &st) < 0)
+    {
+      perror (name);
+      exit (1);
+    }
+
+  fd = open (name, O_RDONLY);
+
+  the_cache = mmap (NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+
+  struct database_pers_head *dps = (struct database_pers_head *) the_cache;
+
+  /* Shortcut for "print the cache offset (address) of X in the
+     cache".  */
+#define A(x) (int)((char *)&(x)-(char *)the_cache)
+
+  /* Common code for "print field DPS->F, it's offset, and contents".  */
+#define DPS(f) printf("%08x: %24s : %10d %08x\n", A (dps->f), #f, (int)dps->f, (int)dps->f);
+
+  if (debug_level > 0)
+    {
+      DPS (version);
+      DPS (header_size);
+      DPS (gc_cycle);
+      DPS (nscd_certainly_running);
+      DPS (timestamp);
+      DPS (module);
+      DPS (data_size);
+      DPS (first_free);
+      DPS (nentries);
+      DPS (maxnentries);
+      DPS (maxnsearched);
+      DPS (poshit);
+      DPS (neghit);
+      DPS (posmiss);
+      DPS (negmiss);
+      DPS (rdlockdelayed);
+      DPS (wrlockdelayed);
+      DPS (addfailed);
+      printf ("\n");
+    }
+
+
+  char *data = (char *) &dps->array[roundup (dps->module,
+					     ALIGN / sizeof (ref_t))];
+
+  /* Loop through each entry in the hash table, which is of size
+     dps->module.  Raw data is stored after the hash table in the
+     cache file.  */
+  for (i = 0; i < dps->module; i++)
+    {
+      ref_t r = dps->array[i];
+      if (r == NO_REF)
+	continue;
+
+      if (debug_level > 2)
+	printf ("hash[%4d] = 0x%x\n", i, r);
+
+      while (r != NO_REF)
+	{
+	  struct hashentry *here = (struct hashentry *) (data + r);
+
+	  unsigned char *key = (unsigned char *) data + here->key;
+
+	  printf ("\n%08x: type %s key %p \"", A (*here),
+		  serv2str[here->type], key);
+
+	  data_string (key, "", here->len);
+
+	  struct datahead *dh = (struct datahead *) (data + here->packet);
+	  printf ("\" (len:%d)  Data %08lx\n", here->len,
+		  (char *) dh - (char *) the_cache);
+
+	  if (debug_level > 0)
+	    {
+/* Common code for printing fields in struct DATAHEAD DH.  */
+#define DH(f) printf ("%08x; %24s : %10d %08x\n", A (dh->f), #f, (int)dh->f, (int)dh->f);
+	      DH (allocsize);
+	      DH (recsize);
+	      DH (timeout);
+	      DH (notfound);
+	      DH (nreloads);
+	      DH (usable);
+	      DH (unused);
+	      DH (ttl);
+	    }
+
+	  unsigned char *cp = (unsigned char *) (&dh->data[0]);
+	  unsigned char *cpe =
+	    (unsigned char *) (&dh->data[0]) + dh->allocsize;
+
+
+	  int i;
+	  uint32_t *grplens;
+
+	  if (debug_level > 1)
+	    {
+	      data_string (cp, _(" - all data: "), cpe - cp);
+	      printf ("\n");
+	    }
+
+	  /* These two are common to all responses.  */
+	  printf ("V%d F%d",
+		  dh->data[0].pwdata.version, dh->data[0].pwdata.found);
+
+/* Shortcut for the common case where we iterate through
+   fixed-length strings stored in the data portion of the
+   cache.  CP is updated to point to the next string.  */
+#define DSTR(str, l) cp = data_string (cp, str, l)
+
+	  switch (here->type)
+	    {
+	    case GETPWBYNAME:
+	    case GETPWBYUID:
+	      {
+		pw_response_header *pw = &(dh->data[0].pwdata);
+		cp += sizeof (*pw);
+		DSTR (" name ", pw->pw_name_len);
+		DSTR (" passwd ", pw->pw_passwd_len);
+		printf (" uid %d gid %d", pw->pw_uid, pw->pw_gid);
+		DSTR (" gecos ", pw->pw_gecos_len);
+		DSTR (" dir ", pw->pw_dir_len);
+		DSTR (" shell ", pw->pw_shell_len);
+		DSTR (" byuid ", -1);
+		DSTR (" key ", -1);
+		printf ("\n");
+	      }
+	      break;
+
+	    case GETGRBYNAME:
+	    case GETGRBYGID:
+	      {
+		gr_response_header *gr = &(dh->data[0].grdata);
+		cp += sizeof (*gr);
+		grplens = (uint32_t *) cp;
+		cp += gr->gr_mem_cnt * sizeof (uint32_t);
+		DSTR (" name ", gr->gr_name_len);
+		DSTR (" passwd ", gr->gr_passwd_len);
+		printf (" gid %d members %d [ ", (int) gr->gr_gid,
+			(int) gr->gr_mem_cnt);
+		for (i = 0; i < gr->gr_mem_cnt; i++)
+		  DSTR (" ", grplens[i]);
+		DSTR (" ] bygid ", -1);
+		DSTR (" key ", -1);
+		printf ("\n");
+	      }
+	      break;
+
+	    case GETHOSTBYADDR:
+	    case GETHOSTBYADDRv6:
+	    case GETHOSTBYNAME:
+	    case GETHOSTBYNAMEv6:
+	      {
+		hst_response_header *hst = &(dh->data[0].hstdata);
+		printf (" addrtype %d error %d", hst->h_addrtype, hst->error);
+		cp += sizeof (*hst);
+		DSTR (" name ", hst->h_name_len);
+		uint32_t *aliases_len = (uint32_t *) cp;
+		cp += hst->h_aliases_cnt * sizeof (uint32_t);
+		uint32_t *addrs = (uint32_t *) cp;
+		cp += hst->h_length * hst->h_addr_list_cnt;
+
+		if (hst->h_aliases_cnt)
+		  {
+		    printf (" aliases [");
+		    for (i = 0; i < hst->h_aliases_cnt; i++)
+		      DSTR (" ", aliases_len[i]);
+		    printf (" ]");
+		  }
+		if (hst->h_addr_list_cnt)
+		  {
+		    char buf[INET6_ADDRSTRLEN];
+		    printf (" addresses [");
+		    for (i = 0; i < hst->h_addr_list_cnt; i++)
+		      {
+			inet_ntop (hst->h_addrtype, addrs, buf, sizeof (buf));
+			printf (" %s", buf);
+			addrs += hst->h_length;
+		      }
+		    printf (" ]");
+		  }
+
+		printf ("\n");
+	      }
+	      break;
+
+	    case GETAI:
+	      {
+		ai_response_header *ai = &(dh->data[0].aidata);
+		printf (" naddrs %d addrslen %d canonlen %d error %d [",
+			ai->naddrs, ai->addrslen, ai->canonlen, ai->error);
+		cp += sizeof (*ai);
+		unsigned char *addrs = cp;
+		unsigned char *families = cp + ai->addrslen;
+		cp = families + ai->naddrs;
+		char buf[INET6_ADDRSTRLEN];
+
+		for (i = 0; i < ai->naddrs; i++)
+		  {
+		    switch (*families)
+		      {
+		      case AF_INET:
+			inet_ntop (*families, addrs, buf, sizeof (buf));
+			printf (" %s", buf);
+			addrs += 4;
+			break;
+		      case AF_INET6:
+			inet_ntop (*families, addrs, buf, sizeof (buf));
+			printf (" %s", buf);
+			addrs += 16;
+			break;
+		      }
+		    families++;
+		  }
+		DSTR (" ] canon ", ai->canonlen);
+		DSTR (" key ", -1);
+		printf ("\n");
+	      }
+	      break;
+
+	    case INITGROUPS:
+	      {
+		initgr_response_header *ig = &(dh->data[0].initgrdata);
+		printf (" nresults %d groups [", (int) ig->ngrps);
+		cp += sizeof (*ig);
+		grplens = (uint32_t *) cp;
+		cp += ig->ngrps * sizeof (uint32_t);
+		for (i = 0; i < ig->ngrps; i++)
+		  printf (" %d", grplens[i]);
+		DSTR (" ] key ", -1);
+		printf ("\n");
+	      }
+	      break;
+
+	    case GETSERVBYNAME:
+	    case GETSERVBYPORT:
+	      {
+		serv_response_header *serv = &(dh->data[0].servdata);
+		printf (" alias_cnt %d port %d (stored as %d)",
+			serv->s_aliases_cnt,
+			((serv->s_port & 0xff00) >> 8) | ((serv->
+							   s_port & 0xff) <<
+							  8), serv->s_port);
+		cp += sizeof (*serv);
+		DSTR (" name ", serv->s_name_len);
+		DSTR (" proto ", serv->s_proto_len);
+		if (serv->s_aliases_cnt)
+		  {
+		    uint32_t *alias_len = (uint32_t *) cp;
+		    printf (" aliases [");
+		    cp += sizeof (uint32_t) * serv->s_aliases_cnt;
+		    for (i = 0; i < serv->s_aliases_cnt; i++)
+		      DSTR (" ", alias_len[i]);
+		    printf (" ]");
+		  }
+		printf ("\n");
+	      }
+	      break;
+
+	    case GETNETGRENT:
+	      {
+		netgroup_response_header *ng = &(dh->data[0].netgroupdata);
+		printf (" nresults %d len %d\n",
+			(int) ng->nresults, (int) ng->result_len);
+		cp += sizeof (*ng);
+		for (i = 0; i < ng->nresults; i++)
+		  {
+		    DSTR (" (", -1);
+		    DSTR (",", -1);
+		    DSTR (",", -1);
+		    printf (")");
+		  }
+		printf ("\n");
+	      }
+	      break;
+
+	    case INNETGR:
+	      {
+		innetgroup_response_header *ing =
+		  &(dh->data[0].innetgroupdata);
+		printf (" result %d\n", ing->result);
+	      }
+	      break;
+
+	    default:
+	      break;
+	    }
+
+	  if (debug_level > 2 && cp && cp < cpe)
+	    {
+	      printf (_(" - remaining data %p: "), cp);
+	      data_string (cp, "", cpe - cp);
+	      printf ("\n");
+	    }
+
+
+	  r = here->next;
+	}
+    }
+
+  munmap (the_cache, st.st_size);
+
+  exit (0);
+}

nscd/nscd.c

@@ -77,6 +77,8 @@ static run_modes run_mode = RUN_DAEMONIZE;
 
 static const char *conffile = _PATH_NSCDCONF;
 
+static const char *print_cache = NULL;
+
 time_t start_time;
 
 uintptr_t pagesize_m1;
@@ -106,6 +108,8 @@ static const struct argp_option options[] =
     N_("Read configuration data from NAME") },
   { "debug", 'd', NULL, 0,
     N_("Do not fork and display messages on the current tty") },
+  { "print", 'p', N_("NAME"), 0,
+    N_("Print contents of the offline cache file NAME") },
   { "foreground", 'F', NULL, 0,
     N_("Do not fork, but otherwise behave like a daemon") },
   { "nthreads", 't', N_("NUMBER"), 0, N_("Start NUMBER threads") },
@@ -157,6 +161,11 @@ main (int argc, char **argv)
       exit (1);
     }
 
+  /* Print the contents of the indicated cache file.  */
+  if (print_cache != NULL)
+    /* Does not return.  */
+    nscd_print_cache (print_cache);
+
   /* Read the configuration file.  */
   if (nscd_parse_file (conffile, dbs) != 0)
     /* We couldn't read the configuration file.  We don't start the
@@ -404,6 +413,10 @@ parse_opt (int key, char *arg, struct argp_state *state)
       run_mode = RUN_DEBUG;
       break;
 
+    case 'p':
+      print_cache = arg;
+      break;
+
     case 'F':
       run_mode = RUN_FOREGROUND;
       break;

nscd/nscd.h

@@ -364,6 +364,8 @@ extern void gc (struct database_dyn *db);
 /* nscd_setup_thread.c */
 extern int setup_thread (struct database_dyn *db);
 
+/* cachedumper.c */
+extern void nscd_print_cache (const char *name);
 
 /* Special version of TEMP_FAILURE_RETRY for functions returning error
    values.  */