Back to index

glibc  2.9
Functions | Variables
nscd_getgr_r.c File Reference
#include <alloca.h>
#include <assert.h>
#include <errno.h>
#include <grp.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <not-cancel.h>
#include <stdio-common/_itoa.h>
#include "nscd-client.h"
#include "nscd_proto.h"

Go to the source code of this file.

Functions

static int nscd_getgr_r (const char *key, size_t keylen, request_type type, struct group *resultbuf, char *buffer, size_t buflen, struct group **result) internal_function
int __nscd_getgrnam_r (const char *name, struct group *resultbuf, char *buffer, size_t buflen, struct group **result)
int __nscd_getgrgid_r (gid_t gid, struct group *resultbuf, char *buffer, size_t buflen, struct group **result)
 libc_locked_map_ptr (__gr_map_handle)

Variables

int __nss_not_use_nscd_group

Function Documentation

int __nscd_getgrgid_r ( gid_t  gid,
struct group resultbuf,
char *  buffer,
size_t  buflen,
struct group **  result 
)

Definition at line 58 of file nscd_getgr_r.c.

{
  char buf[3 * sizeof (gid_t)];
  buf[sizeof (buf) - 1] = '\0';
  char *cp = _itoa_word (gid, buf + sizeof (buf) - 1, 10, 0);

  return nscd_getgr_r (cp, buf + sizeof (buf) - cp, GETGRBYGID, resultbuf,
                     buffer, buflen, result);
}

Here is the call graph for this function:

int __nscd_getgrnam_r ( const char *  name,
struct group resultbuf,
char *  buffer,
size_t  buflen,
struct group **  result 
)

Definition at line 49 of file nscd_getgr_r.c.

{
  return nscd_getgr_r (name, strlen (name) + 1, GETGRBYNAME, resultbuf,
                     buffer, buflen, result);
}

Here is the call graph for this function:

libc_locked_map_ptr ( __gr_map_handle  )

Definition at line 70 of file nscd_getgr_r.c.

{
  if (__gr_map_handle.mapped != NO_MAPPING)
    {
      void *p = __gr_map_handle.mapped;
      __gr_map_handle.mapped = NO_MAPPING;
      free (p);
    }
}
static int internal_function nscd_getgr_r ( const char *  key,
size_t  keylen,
request_type  type,
struct group resultbuf,
char *  buffer,
size_t  buflen,
struct group **  result 
) [static]

Definition at line 87 of file nscd_getgr_r.c.

{
  int gc_cycle;
  int nretries = 0;
  const uint32_t *len = NULL;
  size_t lensize = 0;

  /* If the mapping is available, try to search there instead of
     communicating with the nscd.  */
  struct mapped_database *mapped = __nscd_get_map_ref (GETFDGR, "group",
                                                 &__gr_map_handle,
                                                 &gc_cycle);
 retry:;
  const char *gr_name = NULL;
  size_t gr_name_len = 0;
  int retval = -1;
  const char *recend = (const char *) ~UINTMAX_C (0);
  gr_response_header gr_resp;

  if (mapped != NO_MAPPING)
    {
      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped);
      if (found != NULL)
       {
         len = (const uint32_t *) (&found->data[0].grdata + 1);
         gr_resp = found->data[0].grdata;
         gr_name = ((const char *) len
                   + gr_resp.gr_mem_cnt * sizeof (uint32_t));
         gr_name_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
         recend = (const char *) found->data + found->recsize;
         /* Now check if we can trust gr_resp fields.  If GC is
            in progress, it can contain anything.  */
         if (mapped->head->gc_cycle != gc_cycle)
           {
             retval = -2;
             goto out;
           }

         /* The alignment is always sufficient, unless GC is in progress.  */
         assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
       }
    }

  int sock = -1;
  if (gr_name == NULL)
    {
      sock = __nscd_open_socket (key, keylen, type, &gr_resp,
                             sizeof (gr_resp));
      if (sock == -1)
       {
         __nss_not_use_nscd_group = 1;
         goto out;
       }
    }

  /* No value found so far.  */
  *result = NULL;

  if (__builtin_expect (gr_resp.found == -1, 0))
    {
      /* The daemon does not cache this database.  */
      __nss_not_use_nscd_group = 1;
      goto out_close;
    }

  if (gr_resp.found == 1)
    {
      struct iovec vec[2];
      char *p = buffer;
      size_t total_len;
      uintptr_t align;
      nscd_ssize_t cnt;

      /* Now allocate the buffer the array for the group members.  We must
        align the pointer.  */
      align = ((__alignof__ (char *) - (p - ((char *) 0)))
              & (__alignof__ (char *) - 1));
      total_len = (align + (1 + gr_resp.gr_mem_cnt) * sizeof (char *)
                 + gr_resp.gr_name_len + gr_resp.gr_passwd_len);
      if (__builtin_expect (buflen < total_len, 0))
       {
       no_room:
         __set_errno (ERANGE);
         retval = ERANGE;
         goto out_close;
       }
      buflen -= total_len;

      p += align;
      resultbuf->gr_mem = (char **) p;
      p += (1 + gr_resp.gr_mem_cnt) * sizeof (char *);

      /* Set pointers for strings.  */
      resultbuf->gr_name = p;
      p += gr_resp.gr_name_len;
      resultbuf->gr_passwd = p;
      p += gr_resp.gr_passwd_len;

      /* Fill in what we know now.  */
      resultbuf->gr_gid = gr_resp.gr_gid;

      /* Read the length information, group name, and password.  */
      if (gr_name == NULL)
       {
         /* Handle a simple, usual case: no group members.  */
         if (__builtin_expect (gr_resp.gr_mem_cnt == 0, 1))
           {
             size_t n = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
             if (__builtin_expect (__readall (sock, resultbuf->gr_name, n)
                                != (ssize_t) n, 0))
              goto out_close;
           }
         else
           {
             /* Allocate array to store lengths.  */
             if (lensize == 0)
              {
                lensize = gr_resp.gr_mem_cnt * sizeof (uint32_t);
                len = (uint32_t *) alloca (lensize);
              }
             else if (gr_resp.gr_mem_cnt * sizeof (uint32_t) > lensize)
              len = extend_alloca (len, lensize,
                                 gr_resp.gr_mem_cnt * sizeof (uint32_t));

             vec[0].iov_base = (void *) len;
             vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t);
             vec[1].iov_base = resultbuf->gr_name;
             vec[1].iov_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
             total_len = vec[0].iov_len + vec[1].iov_len;

             /* Get this data.  */
             size_t n = __readvall (sock, vec, 2);
             if (__builtin_expect (n != total_len, 0))
              goto out_close;
           }
       }
      else
       /* We already have the data.  Just copy the group name and
          password.  */
       memcpy (resultbuf->gr_name, gr_name,
              gr_resp.gr_name_len + gr_resp.gr_passwd_len);

      /* Clear the terminating entry.  */
      resultbuf->gr_mem[gr_resp.gr_mem_cnt] = NULL;

      /* Prepare reading the group members.  */
      total_len = 0;
      for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
       {
         resultbuf->gr_mem[cnt] = p;
         total_len += len[cnt];
         p += len[cnt];
       }

      if (__builtin_expect (gr_name + gr_name_len + total_len > recend, 0))
       {
         /* len array might contain garbage during nscd GC cycle,
            retry rather than fail in that case.  */
         if (gr_name != NULL && mapped->head->gc_cycle != gc_cycle)
           retval = -2;
         goto out_close;
       }
      if (__builtin_expect (total_len > buflen, 0))
       {
         /* len array might contain garbage during nscd GC cycle,
            retry rather than fail in that case.  */
         if (gr_name != NULL && mapped->head->gc_cycle != gc_cycle)
           {
             retval = -2;
             goto out_close;
           }
         else
           goto no_room;
       }

      retval = 0;

      /* If there are no group members TOTAL_LEN is zero.  */
      if (gr_name == NULL)
       {
         if (total_len > 0
             && __builtin_expect (__readall (sock, resultbuf->gr_mem[0],
                                         total_len) != total_len, 0))
           {
             /* The `errno' to some value != ERANGE.  */
             __set_errno (ENOENT);
             retval = ENOENT;
           }
         else
           *result = resultbuf;
       }
      else
       {
         /* Copy the group member names.  */
         memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);

         /* Try to detect corrupt databases.  */
         if (resultbuf->gr_name[gr_name_len - 1] != '\0'
             || resultbuf->gr_passwd[gr_resp.gr_passwd_len - 1] != '\0'
             || ({for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
                  if (resultbuf->gr_mem[cnt][len[cnt] - 1] != '\0')
                    break;
                cnt < gr_resp.gr_mem_cnt; }))
           {
             /* We cannot use the database.  */
             retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
             goto out_close;
           }

         *result = resultbuf;
       }
    }
  else
    {
      /* Set errno to 0 to indicate no error, just no found record.  */
      __set_errno (0);
      /* Even though we have not found anything, the result is zero.  */
      retval = 0;
    }

 out_close:
  if (sock != -1)
    close_not_cancel_no_status (sock);
 out:
  if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
    {
      /* When we come here this means there has been a GC cycle while we
        were looking for the data.  This means the data might have been
        inconsistent.  Retry if possible.  */
      if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
       {
         /* nscd is just running gc now.  Disable using the mapping.  */
         if (atomic_decrement_val (&mapped->counter) == 0)
           __nscd_unmap (mapped);
         mapped = NO_MAPPING;
       }

      if (retval != -1)
       goto retry;
    }

  return retval;
}

Here is the call graph for this function:

Here is the caller graph for this function:


Variable Documentation

Definition at line 40 of file nscd_getgr_r.c.