diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | nss/nss_files/files-hosts.c | 294 |
2 files changed, 144 insertions, 156 deletions
diff --git a/ChangeLog b/ChangeLog index f8914f35e5..26e272e25d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2017-10-11 Florian Weimer <fweimer@redhat.com> + + [BZ #18023] + * nss/nss_files/files-hosts.c (gethostbyname3_multi): Use struct + scratch_buffer. Eliminate gotos. + 2017-10-11 Joseph Myers <joseph@codesourcery.com> * sysdeps/ieee754/ldbl-opt/s_clog10l.c: Use diff --git a/nss/nss_files/files-hosts.c b/nss/nss_files/files-hosts.c index 867c10c2ef..763fa39a47 100644 --- a/nss/nss_files/files-hosts.c +++ b/nss/nss_files/files-hosts.c @@ -22,6 +22,7 @@ #include <arpa/nameser.h> #include <netdb.h> #include <resolv/resolv-internal.h> +#include <scratch_buffer.h> /* Get implementation for some internal functions. */ @@ -121,15 +122,12 @@ gethostbyname3_multi (FILE * stream, const char *name, int af, 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 scratch_buffer tmp_buffer; + scratch_buffer_init (&tmp_buffer); 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) @@ -137,181 +135,165 @@ gethostbyname3_multi (FILE * stream, const char *name, int af, 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) + while (true) { - 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 + status = internal_getent (stream, &tmp_result_buf, tmp_buffer.data, + tmp_buffer.length, errnop, herrnop, af, + flags); + /* Enlarge the buffer if necessary. */ + if (status == NSS_STATUS_TRYAGAIN && *herrnop == NETDB_INTERNAL + && *errnop == ERANGE) { - LOOKUP_NAME_CASE (h_name, h_aliases) - result = old_result; + if (!scratch_buffer_grow (&tmp_buffer)) + { + *errnop = ENOMEM; + /* *herrnop and status already have the right value. */ + break; + } + /* Loop around and retry with a larger buffer. */ } - while ((matches = 0)); - - if (matches) + else if (status == NSS_STATUS_SUCCESS) { - /* 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) + /* A line was read. Check that it matches the search + criteria. */ + + 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 { - char *cp = tmp_result_buf.h_aliases[newaliases]; - ++newaliases; - newstrlen += strlen (cp) + 1; + LOOKUP_NAME_CASE (h_name, h_aliases) + result = old_result; } - /* 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) + while ((matches = 0)); + + if (matches) { - ++newaliases; - newstrlen += strlen (tmp_result_buf.h_name) + 1; - } + /* 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); + /* 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; - } + /* 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; + break; + } - new_h_addr_list = - (char **) (bufferend - + roundup (newstrlen, sizeof (char *)) - + 16); - new_h_aliases = - (char **) ((char *) new_h_addr_list - + (naddrs + 2) * sizeof (char *)); + 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]; + /* 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]; + 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; - } + /* 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; - } + 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; + /* Final NULL pointer. */ + new_h_aliases[naliases] = NULL; - /* Round up the buffer end address. */ - bufferend += (sizeof (char *) - - ((bufferend - (char *) 0) - % sizeof (char *))) % sizeof (char *); + /* 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); + /* 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; + /* 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; + /* 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); + /* Compute the new buffer end. */ + bufferend = (char *) &new_h_aliases[naliases + 1]; + assert (bufferend <= buffer + buflen); - result = old_result; - } - } + result = old_result; + } /* If match was found. */ - 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; - } - } + /* If no match is found, loop around and fetch another + line. */ + + } /* status == NSS_STATUS_SUCCESS. */ 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 + /* internal_getent returned an error. */ + break; + } /* while (true) */ + + /* Propagate the NSS_STATUS_TRYAGAIN error to the caller. It means + that we may not have loaded the complete result. + NSS_STATUS_NOTFOUND, however, means that we reached the end of + the file successfully. */ + if (status != NSS_STATUS_TRYAGAIN) status = NSS_STATUS_SUCCESS; - out: - if (tmp_buffer_malloced) - free (tmp_buffer); + + scratch_buffer_free (&tmp_buffer); return status; } |