Prepare for radical source tree reorganization.zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 552 insertions, 0 deletions

diff --git a/REORG.TODO/nscd/pwdcache.c b/REORG.TODO/nscd/pwdcache.c
new file mode 100644
index 0000000000..721f4c617b
--- /dev/null
+++ b/REORG.TODO/nscd/pwdcache.c
@@ -0,0 +1,552 @@
+/* Cache handling for passwd lookup.
+   Copyright (C) 1998-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+   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 <http://www.gnu.org/licenses/>.  */
+
+#include <alloca.h>
+#include <assert.h>
+#include <errno.h>
+#include <error.h>
+#include <libintl.h>
+#include <pwd.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <stackinfo.h>
+
+#include "nscd.h"
+#include "dbg_log.h"
+#ifdef HAVE_SENDFILE
+# include <kernel-features.h>
+#endif
+
+/* This is the standard reply in case the service is disabled.  */
+static const pw_response_header disabled =
+{
+  .version = NSCD_VERSION,
+  .found = -1,
+  .pw_name_len = 0,
+  .pw_passwd_len = 0,
+  .pw_uid = -1,
+  .pw_gid = -1,
+  .pw_gecos_len = 0,
+  .pw_dir_len = 0,
+  .pw_shell_len = 0
+};
+
+/* This is the struct describing how to write this record.  */
+const struct iovec pwd_iov_disabled =
+{
+  .iov_base = (void *) &disabled,
+  .iov_len = sizeof (disabled)
+};
+
+
+/* This is the standard reply in case we haven't found the dataset.  */
+static const pw_response_header notfound =
+{
+  .version = NSCD_VERSION,
+  .found = 0,
+  .pw_name_len = 0,
+  .pw_passwd_len = 0,
+  .pw_uid = -1,
+  .pw_gid = -1,
+  .pw_gecos_len = 0,
+  .pw_dir_len = 0,
+  .pw_shell_len = 0
+};
+
+
+static time_t
+cache_addpw (struct database_dyn *db, int fd, request_header *req,
+	     const void *key, struct passwd *pwd, uid_t owner,
+	     struct hashentry *const he, struct datahead *dh, int errval)
+{
+  bool all_written = true;
+  ssize_t total;
+  time_t t = time (NULL);
+
+  /* We allocate all data in one memory block: the iov vector,
+     the response header and the dataset itself.  */
+  struct dataset
+  {
+    struct datahead head;
+    pw_response_header resp;
+    char strdata[0];
+  } *dataset;
+
+  assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
+
+  time_t timeout = MAX_TIMEOUT_VALUE;
+  if (pwd == NULL)
+    {
+      if (he != NULL && errval == EAGAIN)
+	{
+	  /* If we have an old record available but cannot find one
+	     now because the service is not available we keep the old
+	     record and make sure it does not get removed.  */
+	  if (reload_count != UINT_MAX && dh->nreloads == reload_count)
+	    /* Do not reset the value if we never not reload the record.  */
+	    dh->nreloads = reload_count - 1;
+
+	  /* Reload with the same time-to-live value.  */
+	  timeout = dh->timeout = t + db->postimeout;
+
+	  total = 0;
+	}
+      else
+	{
+	  /* We have no data.  This means we send the standard reply for this
+	     case.  */
+	  total = sizeof (notfound);
+
+	  if (fd != -1
+	      && TEMP_FAILURE_RETRY (send (fd, &notfound, total,
+					   MSG_NOSIGNAL)) != total)
+	    all_written = false;
+
+	  /* If we have a transient error or cannot permanently store
+	     the result, so be it.  */
+	  if (errno == EAGAIN || __builtin_expect (db->negtimeout == 0, 0))
+	    {
+	      /* Mark the old entry as obsolete.  */
+	      if (dh != NULL)
+		dh->usable = false;
+	    }
+	  else if ((dataset = mempool_alloc (db, (sizeof (struct dataset)
+						  + req->key_len), 1)) != NULL)
+	    {
+	      timeout = datahead_init_neg (&dataset->head,
+					   (sizeof (struct dataset)
+					    + req->key_len), total,
+					   db->negtimeout);
+
+	      /* This is the reply.  */
+	      memcpy (&dataset->resp, &notfound, total);
+
+	      /* Copy the key data.  */
+	      char *key_copy = memcpy (dataset->strdata, key, req->key_len);
+
+	      /* If necessary, we also propagate the data to disk.  */
+	      if (db->persistent)
+		{
+		  // XXX async OK?
+		  uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
+		  msync ((void *) pval,
+			 ((uintptr_t) dataset & pagesize_m1)
+			 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
+		}
+
+	      (void) cache_add (req->type, key_copy, req->key_len,
+				&dataset->head, true, db, owner, he == NULL);
+
+	      pthread_rwlock_unlock (&db->lock);
+
+	      /* Mark the old entry as obsolete.  */
+	      if (dh != NULL)
+		dh->usable = false;
+	    }
+	}
+    }
+  else
+    {
+      /* Determine the I/O structure.  */
+      size_t pw_name_len = strlen (pwd->pw_name) + 1;
+      size_t pw_passwd_len = strlen (pwd->pw_passwd) + 1;
+      size_t pw_gecos_len = strlen (pwd->pw_gecos) + 1;
+      size_t pw_dir_len = strlen (pwd->pw_dir) + 1;
+      size_t pw_shell_len = strlen (pwd->pw_shell) + 1;
+      char *cp;
+      const size_t key_len = strlen (key);
+      const size_t buf_len = 3 * sizeof (pwd->pw_uid) + key_len + 1;
+      char *buf = alloca (buf_len);
+      ssize_t n;
+
+      /* We need this to insert the `byuid' entry.  */
+      int key_offset;
+      n = snprintf (buf, buf_len, "%d%c%n%s", pwd->pw_uid, '\0',
+		    &key_offset, (char *) key) + 1;
+
+      total = (offsetof (struct dataset, strdata)
+	       + pw_name_len + pw_passwd_len
+	       + pw_gecos_len + pw_dir_len + pw_shell_len);
+
+      /* If we refill the cache, first assume the reconrd did not
+	 change.  Allocate memory on the cache since it is likely
+	 discarded anyway.  If it turns out to be necessary to have a
+	 new record we can still allocate real memory.  */
+      bool alloca_used = false;
+      dataset = NULL;
+
+      if (he == NULL)
+	{
+	  /* Prevent an INVALIDATE request from pruning the data between
+	     the two calls to cache_add.  */
+	  if (db->propagate)
+	    pthread_mutex_lock (&db->prune_run_lock);
+	  dataset = (struct dataset *) mempool_alloc (db, total + n, 1);
+	}
+
+      if (dataset == NULL)
+	{
+	  if (he == NULL && db->propagate)
+	    pthread_mutex_unlock (&db->prune_run_lock);
+
+	  /* We cannot permanently add the result in the moment.  But
+	     we can provide the result as is.  Store the data in some
+	     temporary memory.  */
+	  dataset = (struct dataset *) alloca (total + n);
+
+	  /* We cannot add this record to the permanent database.  */
+	  alloca_used = true;
+	}
+
+      timeout = datahead_init_pos (&dataset->head, total + n,
+				   total - offsetof (struct dataset, resp),
+				   he == NULL ? 0 : dh->nreloads + 1,
+				   db->postimeout);
+
+      dataset->resp.version = NSCD_VERSION;
+      dataset->resp.found = 1;
+      dataset->resp.pw_name_len = pw_name_len;
+      dataset->resp.pw_passwd_len = pw_passwd_len;
+      dataset->resp.pw_uid = pwd->pw_uid;
+      dataset->resp.pw_gid = pwd->pw_gid;
+      dataset->resp.pw_gecos_len = pw_gecos_len;
+      dataset->resp.pw_dir_len = pw_dir_len;
+      dataset->resp.pw_shell_len = pw_shell_len;
+
+      cp = dataset->strdata;
+
+      /* Copy the strings over into the buffer.  */
+      cp = mempcpy (cp, pwd->pw_name, pw_name_len);
+      cp = mempcpy (cp, pwd->pw_passwd, pw_passwd_len);
+      cp = mempcpy (cp, pwd->pw_gecos, pw_gecos_len);
+      cp = mempcpy (cp, pwd->pw_dir, pw_dir_len);
+      cp = mempcpy (cp, pwd->pw_shell, pw_shell_len);
+
+      /* Finally the stringified UID value.  */
+      memcpy (cp, buf, n);
+      char *key_copy = cp + key_offset;
+      assert (key_copy == (char *) rawmemchr (cp, '\0') + 1);
+
+      assert (cp == dataset->strdata + total - offsetof (struct dataset,
+							 strdata));
+
+      /* Now we can determine whether on refill we have to create a new
+	 record or not.  */
+      if (he != NULL)
+	{
+	  assert (fd == -1);
+
+	  if (dataset->head.allocsize == dh->allocsize
+	      && dataset->head.recsize == dh->recsize
+	      && memcmp (&dataset->resp, dh->data,
+			 dh->allocsize - offsetof (struct dataset, resp)) == 0)
+	    {
+	      /* The data has not changed.  We will just bump the
+		 timeout value.  Note that the new record has been
+		 allocated on the stack and need not be freed.  */
+	      dh->timeout = dataset->head.timeout;
+	      ++dh->nreloads;
+	    }
+	  else
+	    {
+	      /* We have to create a new record.  Just allocate
+		 appropriate memory and copy it.  */
+	      struct dataset *newp
+		= (struct dataset *) mempool_alloc (db, total + n, 1);
+	      if (newp != NULL)
+		{
+		  /* Adjust pointer into the memory block.  */
+		  cp = (char *) newp + (cp - (char *) dataset);
+		  key_copy = (char *) newp + (key_copy - (char *) dataset);
+
+		  dataset = memcpy (newp, dataset, total + n);
+		  alloca_used = false;
+		}
+
+	      /* Mark the old record as obsolete.  */
+	      dh->usable = false;
+	    }
+	}
+      else
+	{
+	  /* We write the dataset before inserting it to the database
+	     since while inserting this thread might block and so would
+	     unnecessarily let the receiver wait.  */
+	  assert (fd != -1);
+
+#ifdef HAVE_SENDFILE
+	  if (__builtin_expect (db->mmap_used, 1) && !alloca_used)
+	    {
+	      assert (db->wr_fd != -1);
+	      assert ((char *) &dataset->resp > (char *) db->data);
+	      assert ((char *) dataset - (char *) db->head
+		      + total
+		      <= (sizeof (struct database_pers_head)
+			  + db->head->module * sizeof (ref_t)
+			  + db->head->data_size));
+	      ssize_t written = sendfileall (fd, db->wr_fd,
+					     (char *) &dataset->resp
+					     - (char *) db->head,
+					     dataset->head.recsize);
+	      if (written != dataset->head.recsize)
+		{
+# ifndef __ASSUME_SENDFILE
+		  if (written == -1 && errno == ENOSYS)
+		    goto use_write;
+# endif
+		  all_written = false;
+		}
+	    }
+	  else
+# ifndef __ASSUME_SENDFILE
+	  use_write:
+# endif
+#endif
+	    if (writeall (fd, &dataset->resp, dataset->head.recsize)
+		!= dataset->head.recsize)
+	      all_written = false;
+	}
+
+
+      /* Add the record to the database.  But only if it has not been
+	 stored on the stack.  */
+      if (! alloca_used)
+	{
+	  /* If necessary, we also propagate the data to disk.  */
+	  if (db->persistent)
+	    {
+	      // XXX async OK?
+	      uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
+	      msync ((void *) pval,
+		     ((uintptr_t) dataset & pagesize_m1) + total + n,
+		     MS_ASYNC);
+	    }
+
+	  /* NB: in the following code we always must add the entry
+	     marked with FIRST first.  Otherwise we end up with
+	     dangling "pointers" in case a latter hash entry cannot be
+	     added.  */
+	  bool first = true;
+
+	  /* If the request was by UID, add that entry first.  */
+	  if (req->type == GETPWBYUID)
+	    {
+	      if (cache_add (GETPWBYUID, cp, key_offset, &dataset->head, true,
+			     db, owner, he == NULL) < 0)
+		goto out;
+
+	      first = false;
+	    }
+	  /* If the key is different from the name add a separate entry.  */
+	  else if (strcmp (key_copy, dataset->strdata) != 0)
+	    {
+	      if (cache_add (GETPWBYNAME, key_copy, key_len + 1,
+			     &dataset->head, true, db, owner, he == NULL) < 0)
+		goto out;
+
+	      first = false;
+	    }
+
+	  /* We have to add the value for both, byname and byuid.  */
+	  if ((req->type == GETPWBYNAME || db->propagate)
+	      && __builtin_expect (cache_add (GETPWBYNAME, dataset->strdata,
+					      pw_name_len, &dataset->head,
+					      first, db, owner, he == NULL)
+				   == 0, 1))
+	    {
+	      if (req->type == GETPWBYNAME && db->propagate)
+		(void) cache_add (GETPWBYUID, cp, key_offset, &dataset->head,
+				  false, db, owner, false);
+	    }
+
+	out:
+	  pthread_rwlock_unlock (&db->lock);
+	  if (he == NULL && db->propagate)
+	    pthread_mutex_unlock (&db->prune_run_lock);
+	}
+    }
+
+  if (__builtin_expect (!all_written, 0) && debug_level > 0)
+    {
+      char buf[256];
+      dbg_log (_("short write in %s: %s"),  __FUNCTION__,
+	       strerror_r (errno, buf, sizeof (buf)));
+    }
+
+  return timeout;
+}
+
+
+union keytype
+{
+  void *v;
+  uid_t u;
+};
+
+
+static int
+lookup (int type, union keytype key, struct passwd *resultbufp, char *buffer,
+	size_t buflen, struct passwd **pwd)
+{
+  if (type == GETPWBYNAME)
+    return __getpwnam_r (key.v, resultbufp, buffer, buflen, pwd);
+  else
+    return __getpwuid_r (key.u, resultbufp, buffer, buflen, pwd);
+}
+
+
+static time_t
+addpwbyX (struct database_dyn *db, int fd, request_header *req,
+	  union keytype key, const char *keystr, uid_t c_uid,
+	  struct hashentry *he, struct datahead *dh)
+{
+  /* Search for the entry matching the key.  Please note that we don't
+     look again in the table whether the dataset is now available.  We
+     simply insert it.  It does not matter if it is in there twice.  The
+     pruning function only will look at the timestamp.  */
+  size_t buflen = 1024;
+  char *buffer = (char *) alloca (buflen);
+  struct passwd resultbuf;
+  struct passwd *pwd;
+  bool use_malloc = false;
+  int errval = 0;
+
+  if (__glibc_unlikely (debug_level > 0))
+    {
+      if (he == NULL)
+	dbg_log (_("Haven't found \"%s\" in password cache!"), keystr);
+      else
+	dbg_log (_("Reloading \"%s\" in password cache!"), keystr);
+    }
+
+  while (lookup (req->type, key, &resultbuf, buffer, buflen, &pwd) != 0
+	 && (errval = errno) == ERANGE)
+    {
+      errno = 0;
+
+      if (__glibc_unlikely (buflen > 32768))
+	{
+	  char *old_buffer = buffer;
+	  buflen *= 2;
+	  buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
+	  if (buffer == NULL)
+	    {
+	      /* We ran out of memory.  We cannot do anything but
+		 sending a negative response.  In reality this should
+		 never happen.  */
+	      pwd = NULL;
+	      buffer = old_buffer;
+
+	      /* We set the error to indicate this is (possibly) a
+		 temporary error and that it does not mean the entry
+		 is not available at all.  */
+	      errval = EAGAIN;
+	      break;
+	    }
+	  use_malloc = true;
+	}
+      else
+	/* Allocate a new buffer on the stack.  If possible combine it
+	   with the previously allocated buffer.  */
+	buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
+    }
+
+  /* Add the entry to the cache.  */
+  time_t timeout = cache_addpw (db, fd, req, keystr, pwd, c_uid, he, dh,
+				errval);
+
+  if (use_malloc)
+    free (buffer);
+
+  return timeout;
+}
+
+
+void
+addpwbyname (struct database_dyn *db, int fd, request_header *req,
+	     void *key, uid_t c_uid)
+{
+  union keytype u = { .v = key };
+
+  addpwbyX (db, fd, req, u, key, c_uid, NULL, NULL);
+}
+
+
+time_t
+readdpwbyname (struct database_dyn *db, struct hashentry *he,
+	       struct datahead *dh)
+{
+  request_header req =
+    {
+      .type = GETPWBYNAME,
+      .key_len = he->len
+    };
+  union keytype u = { .v = db->data + he->key };
+
+  return addpwbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
+}
+
+
+void
+addpwbyuid (struct database_dyn *db, int fd, request_header *req,
+	    void *key, uid_t c_uid)
+{
+  char *ep;
+  uid_t uid = strtoul ((char *) key, &ep, 10);
+
+  if (*(char *) key == '\0' || *ep != '\0')  /* invalid numeric uid */
+    {
+      if (debug_level > 0)
+	dbg_log (_("Invalid numeric uid \"%s\"!"), (char *) key);
+
+      errno = EINVAL;
+      return;
+    }
+
+  union keytype u = { .u = uid };
+
+  addpwbyX (db, fd, req, u, key, c_uid, NULL, NULL);
+}
+
+
+time_t
+readdpwbyuid (struct database_dyn *db, struct hashentry *he,
+	      struct datahead *dh)
+{
+  char *ep;
+  uid_t uid = strtoul (db->data + he->key, &ep, 10);
+
+  /* Since the key has been added before it must be OK.  */
+  assert (*(db->data + he->key) != '\0' && *ep == '\0');
+
+  request_header req =
+    {
+      .type = GETPWBYUID,
+      .key_len = he->len
+    };
+  union keytype u = { .u = uid };
+
+  return addpwbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
+}