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authorFlorian Weimer <fweimer@redhat.com>2017-10-10 11:50:41 +0200
committerFlorian Weimer <fweimer@redhat.com>2017-10-10 11:50:42 +0200
commit8ed70de2faceb4bd7b35bbdc2b7e8c83d9a297ba (patch)
tree7a265a9c8221f5c1690a8a70a1cc797cda279602 /nss
parenta8dce6197a646fcf870dd2e87069eba3c99099e1 (diff)
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nss_files: Refactor gethostbyname3 multi case into separate function
This is in preparation of further cleanup work.
Diffstat (limited to 'nss')
-rw-r--r--nss/nss_files/files-hosts.c395
1 files changed, 202 insertions, 193 deletions
diff --git a/nss/nss_files/files-hosts.c b/nss/nss_files/files-hosts.c
index bccb6a5..867c10c 100644
--- a/nss/nss_files/files-hosts.c
+++ b/nss/nss_files/files-hosts.c
@@ -115,6 +115,206 @@ DB_LOOKUP (hostbyaddr, ,,,
}, const void *addr, socklen_t len, int af)
#undef EXTRA_ARGS_VALUE
+static enum nss_status
+gethostbyname3_multi (FILE * stream, const char *name, int af,
+ struct hostent *result, char *buffer, size_t buflen,
+ int *errnop, int *herrnop, int flags)
+{
+ /* We have to get all host entries from the file. */
+ size_t tmp_buflen = MIN (buflen, 4096);
+ char tmp_buffer_stack[tmp_buflen]
+ __attribute__ ((__aligned__ (__alignof__ (struct hostent_data))));
+ char *tmp_buffer = tmp_buffer_stack;
+ struct hostent tmp_result_buf;
+ int naddrs = 1;
+ int naliases = 0;
+ char *bufferend;
+ bool tmp_buffer_malloced = false;
+ enum nss_status status;
+
+ while (result->h_aliases[naliases] != NULL)
+ ++naliases;
+
+ bufferend = (char *) &result->h_aliases[naliases + 1];
+
+ again:
+ while ((status = internal_getent (stream, &tmp_result_buf, tmp_buffer,
+ tmp_buflen, errnop, herrnop, af,
+ flags))
+ == NSS_STATUS_SUCCESS)
+ {
+ int matches = 1;
+ struct hostent *old_result = result;
+ result = &tmp_result_buf;
+ /* The following piece is a bit clumsy but we want to use the
+ `LOOKUP_NAME_CASE' value. The optimizer should do its
+ job. */
+ do
+ {
+ LOOKUP_NAME_CASE (h_name, h_aliases)
+ result = old_result;
+ }
+ while ((matches = 0));
+
+ if (matches)
+ {
+ /* We could be very clever and try to recycle a few bytes
+ in the buffer instead of generating new arrays. But
+ we are not doing this here since it's more work than
+ it's worth. Simply let the user provide a bit bigger
+ buffer. */
+ char **new_h_addr_list;
+ char **new_h_aliases;
+ int newaliases = 0;
+ size_t newstrlen = 0;
+ int cnt;
+
+ /* Count the new aliases and the length of the strings. */
+ while (tmp_result_buf.h_aliases[newaliases] != NULL)
+ {
+ char *cp = tmp_result_buf.h_aliases[newaliases];
+ ++newaliases;
+ newstrlen += strlen (cp) + 1;
+ }
+ /* If the real name is different add it also to the
+ aliases. This means that there is a duplication
+ in the alias list but this is really the user's
+ problem. */
+ if (strcmp (old_result->h_name,
+ tmp_result_buf.h_name) != 0)
+ {
+ ++newaliases;
+ newstrlen += strlen (tmp_result_buf.h_name) + 1;
+ }
+
+ /* Make sure bufferend is aligned. */
+ assert ((bufferend - (char *) 0) % sizeof (char *) == 0);
+
+ /* Now we can check whether the buffer is large enough.
+ 16 is the maximal size of the IP address. */
+ if (bufferend + 16 + (naddrs + 2) * sizeof (char *)
+ + roundup (newstrlen, sizeof (char *))
+ + (naliases + newaliases + 1) * sizeof (char *)
+ >= buffer + buflen)
+ {
+ *errnop = ERANGE;
+ *herrnop = NETDB_INTERNAL;
+ status = NSS_STATUS_TRYAGAIN;
+ goto out;
+ }
+
+ new_h_addr_list =
+ (char **) (bufferend
+ + roundup (newstrlen, sizeof (char *))
+ + 16);
+ new_h_aliases =
+ (char **) ((char *) new_h_addr_list
+ + (naddrs + 2) * sizeof (char *));
+
+ /* Copy the old data in the new arrays. */
+ for (cnt = 0; cnt < naddrs; ++cnt)
+ new_h_addr_list[cnt] = old_result->h_addr_list[cnt];
+
+ for (cnt = 0; cnt < naliases; ++cnt)
+ new_h_aliases[cnt] = old_result->h_aliases[cnt];
+
+ /* Store the new strings. */
+ cnt = 0;
+ while (tmp_result_buf.h_aliases[cnt] != NULL)
+ {
+ new_h_aliases[naliases++] = bufferend;
+ bufferend = (__stpcpy (bufferend,
+ tmp_result_buf.h_aliases[cnt])
+ + 1);
+ ++cnt;
+ }
+
+ if (cnt < newaliases)
+ {
+ new_h_aliases[naliases++] = bufferend;
+ bufferend = __stpcpy (bufferend,
+ tmp_result_buf.h_name) + 1;
+ }
+
+ /* Final NULL pointer. */
+ new_h_aliases[naliases] = NULL;
+
+ /* Round up the buffer end address. */
+ bufferend += (sizeof (char *)
+ - ((bufferend - (char *) 0)
+ % sizeof (char *))) % sizeof (char *);
+
+ /* Now the new address. */
+ new_h_addr_list[naddrs++] =
+ memcpy (bufferend, tmp_result_buf.h_addr,
+ tmp_result_buf.h_length);
+
+ /* Also here a final NULL pointer. */
+ new_h_addr_list[naddrs] = NULL;
+
+ /* Store the new array pointers. */
+ old_result->h_aliases = new_h_aliases;
+ old_result->h_addr_list = new_h_addr_list;
+
+ /* Compute the new buffer end. */
+ bufferend = (char *) &new_h_aliases[naliases + 1];
+ assert (bufferend <= buffer + buflen);
+
+ result = old_result;
+ }
+ }
+
+ if (status == NSS_STATUS_TRYAGAIN)
+ {
+ size_t newsize = 2 * tmp_buflen;
+ if (tmp_buffer_malloced)
+ {
+ char *newp = realloc (tmp_buffer, newsize);
+ if (newp != NULL)
+ {
+ assert ((((uintptr_t) newp)
+ & (__alignof__ (struct hostent_data) - 1))
+ == 0);
+ tmp_buffer = newp;
+ tmp_buflen = newsize;
+ goto again;
+ }
+ }
+ else if (!__libc_use_alloca (buflen + newsize))
+ {
+ tmp_buffer = malloc (newsize);
+ if (tmp_buffer != NULL)
+ {
+ assert ((((uintptr_t) tmp_buffer)
+ & (__alignof__ (struct hostent_data) - 1))
+ == 0);
+ tmp_buffer_malloced = true;
+ tmp_buflen = newsize;
+ goto again;
+ }
+ }
+ else
+ {
+ tmp_buffer
+ = extend_alloca (tmp_buffer, tmp_buflen,
+ newsize
+ + __alignof__ (struct hostent_data));
+ tmp_buffer = (char *) (((uintptr_t) tmp_buffer
+ + __alignof__ (struct hostent_data)
+ - 1)
+ & ~(__alignof__ (struct hostent_data)
+ - 1));
+ goto again;
+ }
+ }
+ else
+ status = NSS_STATUS_SUCCESS;
+ out:
+ if (tmp_buffer_malloced)
+ free (tmp_buffer);
+ return status;
+}
+
enum nss_status
_nss_files_gethostbyname3_r (const char *name, int af, struct hostent *result,
char *buffer, size_t buflen, int *errnop,
@@ -143,199 +343,8 @@ _nss_files_gethostbyname3_r (const char *name, int af, struct hostent *result,
if (status == NSS_STATUS_SUCCESS
&& _res_hconf.flags & HCONF_FLAG_MULTI)
- {
- /* We have to get all host entries from the file. */
- size_t tmp_buflen = MIN (buflen, 4096);
- char tmp_buffer_stack[tmp_buflen]
- __attribute__ ((__aligned__ (__alignof__ (struct hostent_data))));
- char *tmp_buffer = tmp_buffer_stack;
- struct hostent tmp_result_buf;
- int naddrs = 1;
- int naliases = 0;
- char *bufferend;
- bool tmp_buffer_malloced = false;
-
- while (result->h_aliases[naliases] != NULL)
- ++naliases;
-
- bufferend = (char *) &result->h_aliases[naliases + 1];
-
- again:
- while ((status = internal_getent (stream, &tmp_result_buf, tmp_buffer,
- tmp_buflen, errnop, herrnop, af,
- flags))
- == NSS_STATUS_SUCCESS)
- {
- int matches = 1;
- struct hostent *old_result = result;
- result = &tmp_result_buf;
- /* The following piece is a bit clumsy but we want to use the
- `LOOKUP_NAME_CASE' value. The optimizer should do its
- job. */
- do
- {
- LOOKUP_NAME_CASE (h_name, h_aliases)
- result = old_result;
- }
- while ((matches = 0));
-
- if (matches)
- {
- /* We could be very clever and try to recycle a few bytes
- in the buffer instead of generating new arrays. But
- we are not doing this here since it's more work than
- it's worth. Simply let the user provide a bit bigger
- buffer. */
- char **new_h_addr_list;
- char **new_h_aliases;
- int newaliases = 0;
- size_t newstrlen = 0;
- int cnt;
-
- /* Count the new aliases and the length of the strings. */
- while (tmp_result_buf.h_aliases[newaliases] != NULL)
- {
- char *cp = tmp_result_buf.h_aliases[newaliases];
- ++newaliases;
- newstrlen += strlen (cp) + 1;
- }
- /* If the real name is different add it also to the
- aliases. This means that there is a duplication
- in the alias list but this is really the user's
- problem. */
- if (strcmp (old_result->h_name,
- tmp_result_buf.h_name) != 0)
- {
- ++newaliases;
- newstrlen += strlen (tmp_result_buf.h_name) + 1;
- }
-
- /* Make sure bufferend is aligned. */
- assert ((bufferend - (char *) 0) % sizeof (char *) == 0);
-
- /* Now we can check whether the buffer is large enough.
- 16 is the maximal size of the IP address. */
- if (bufferend + 16 + (naddrs + 2) * sizeof (char *)
- + roundup (newstrlen, sizeof (char *))
- + (naliases + newaliases + 1) * sizeof (char *)
- >= buffer + buflen)
- {
- *errnop = ERANGE;
- *herrnop = NETDB_INTERNAL;
- status = NSS_STATUS_TRYAGAIN;
- goto out;
- }
-
- new_h_addr_list =
- (char **) (bufferend
- + roundup (newstrlen, sizeof (char *))
- + 16);
- new_h_aliases =
- (char **) ((char *) new_h_addr_list
- + (naddrs + 2) * sizeof (char *));
-
- /* Copy the old data in the new arrays. */
- for (cnt = 0; cnt < naddrs; ++cnt)
- new_h_addr_list[cnt] = old_result->h_addr_list[cnt];
-
- for (cnt = 0; cnt < naliases; ++cnt)
- new_h_aliases[cnt] = old_result->h_aliases[cnt];
-
- /* Store the new strings. */
- cnt = 0;
- while (tmp_result_buf.h_aliases[cnt] != NULL)
- {
- new_h_aliases[naliases++] = bufferend;
- bufferend = (__stpcpy (bufferend,
- tmp_result_buf.h_aliases[cnt])
- + 1);
- ++cnt;
- }
-
- if (cnt < newaliases)
- {
- new_h_aliases[naliases++] = bufferend;
- bufferend = __stpcpy (bufferend,
- tmp_result_buf.h_name) + 1;
- }
-
- /* Final NULL pointer. */
- new_h_aliases[naliases] = NULL;
-
- /* Round up the buffer end address. */
- bufferend += (sizeof (char *)
- - ((bufferend - (char *) 0)
- % sizeof (char *))) % sizeof (char *);
-
- /* Now the new address. */
- new_h_addr_list[naddrs++] =
- memcpy (bufferend, tmp_result_buf.h_addr,
- tmp_result_buf.h_length);
-
- /* Also here a final NULL pointer. */
- new_h_addr_list[naddrs] = NULL;
-
- /* Store the new array pointers. */
- old_result->h_aliases = new_h_aliases;
- old_result->h_addr_list = new_h_addr_list;
-
- /* Compute the new buffer end. */
- bufferend = (char *) &new_h_aliases[naliases + 1];
- assert (bufferend <= buffer + buflen);
-
- result = old_result;
- }
- }
-
- if (status == NSS_STATUS_TRYAGAIN)
- {
- size_t newsize = 2 * tmp_buflen;
- if (tmp_buffer_malloced)
- {
- char *newp = realloc (tmp_buffer, newsize);
- if (newp != NULL)
- {
- assert ((((uintptr_t) newp)
- & (__alignof__ (struct hostent_data) - 1))
- == 0);
- tmp_buffer = newp;
- tmp_buflen = newsize;
- goto again;
- }
- }
- else if (!__libc_use_alloca (buflen + newsize))
- {
- tmp_buffer = malloc (newsize);
- if (tmp_buffer != NULL)
- {
- assert ((((uintptr_t) tmp_buffer)
- & (__alignof__ (struct hostent_data) - 1))
- == 0);
- tmp_buffer_malloced = true;
- tmp_buflen = newsize;
- goto again;
- }
- }
- else
- {
- tmp_buffer
- = extend_alloca (tmp_buffer, tmp_buflen,
- newsize
- + __alignof__ (struct hostent_data));
- tmp_buffer = (char *) (((uintptr_t) tmp_buffer
- + __alignof__ (struct hostent_data)
- - 1)
- & ~(__alignof__ (struct hostent_data)
- - 1));
- goto again;
- }
- }
- else
- status = NSS_STATUS_SUCCESS;
- out:
- if (tmp_buffer_malloced)
- free (tmp_buffer);
- }
+ status = gethostbyname3_multi
+ (stream, name, af, result, buffer, buflen, errnop, herrnop, flags);
internal_endent (&stream);
}