diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | nss/nss_files/files-hosts.c | 395 |
2 files changed, 208 insertions, 193 deletions
@@ -1,3 +1,9 @@ +2017-10-10 Florian Weimer <fweimer@redhat.com> + + * nss/nss_files/files-hosts.c (gethostbyname3_multi): New + function. + (_nss_files_gethostbyname3_r): Call it. + 2017-10-09 Joseph Myers <joseph@codesourcery.com> * sysdeps/generic/math-type-macros.h [!declare_mgen_alias]: Give 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); } |