Every aligning requires at least one cast and it's hard to read. Let's make a function that makes sure the pointer is moved according to the alignment and use that to move throughout the data buffer. Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com&gt; --- v2: - Initialize @idx in _nss_libvirt_gethostbyname4_r as well tools/nss/libvirt_nss.c | 53 +++++++++++++++++++++++++++++++------------------ 1 file changed, 34 insertions(+), 19 deletions(-) diff --git a/tools/nss/libvirt_nss.c b/tools/nss/libvirt_nss.c index ba3bb31b3569..218c62a64c88 100644 --- a/tools/nss/libvirt_nss.c +++ b/tools/nss/libvirt_nss.c @@ -252,17 +252,31 @@ _nss_libvirt_gethostbyname2_r(const char *name, int af, struct hostent *result, errnop, herrnop, NULL, NULL); } +static inline void * +move_and_align(void *buf, size_t len, size_t *idx) +{ + char *buffer = buf; + size_t move = ALIGN(len); + + if (!idx) + return buffer + move; + + *idx += move; + + return buffer + *idx; +} + enum nss_status _nss_libvirt_gethostbyname3_r(const char *name, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *herrnop, int32_t *ttlp, char **canonp) { enum nss_status ret = NSS_STATUS_UNAVAIL; - char *r_name, **r_aliases, *r_addr, **r_addr_list; + char *r_name, **r_aliases, *r_addr, *r_addr_next, **r_addr_list; leaseAddress *addr = NULL; size_t naddr, i; bool found = false; - size_t nameLen, need, idx; + size_t nameLen, need, idx = 0; int alen; int r; @@ -319,23 +333,27 @@ _nss_libvirt_gethostbyname3_r(const char *name, int af, struct hostent *result, /* First, append name */ r_name = buffer; memcpy(r_name, name, nameLen + 1); - idx = ALIGN(nameLen + 1); + + r_aliases = move_and_align(buffer, nameLen + 1, &idx); /* Second, create aliases array */ - r_aliases = (char **) buffer + idx; r_aliases[0] = NULL; - idx += sizeof(char*); /* Third, append address */ - r_addr = buffer + idx; - for (i = 0; i < naddr; i++) - memcpy(r_addr + i * ALIGN(alen), addr[i].addr, alen); - idx += naddr * ALIGN(alen); + r_addr = move_and_align(buffer, sizeof(char *), &idx); + r_addr_next = r_addr; + for (i = 0; i < naddr; i++) { + memcpy(r_addr_next, addr[i].addr, alen); + r_addr_next = move_and_align(buffer, alen, &idx); + } + r_addr_list = move_and_align(buffer, 0, &idx); + r_addr_next = r_addr; /* Third, append address pointer array */ - r_addr_list = (char **) buffer + idx; - for (i = 0; i < naddr; i++) - r_addr_list[i] = r_addr + i * ALIGN(alen); + for (i = 0; i < naddr; i++) { + r_addr_list[i] = r_addr_next; + r_addr_next = move_and_align(r_addr_next, alen, NULL); + } r_addr_list[i] = NULL; idx += (naddr + 1) * sizeof(char*); @@ -375,7 +393,7 @@ _nss_libvirt_gethostbyname4_r(const char *name, struct gaih_addrtuple **pat, size_t naddr, i; bool found = false; int r; - size_t nameLen, need, idx; + size_t nameLen, need, idx = 0; struct gaih_addrtuple *r_tuple, *r_tuple_first = NULL; char *r_name; @@ -420,25 +438,22 @@ _nss_libvirt_gethostbyname4_r(const char *name, struct gaih_addrtuple **pat, /* First, append name */ r_name = buffer; memcpy(r_name, name, nameLen + 1); - idx = ALIGN(nameLen + 1); - /* Second, append addresses */ - r_tuple_first = (struct gaih_addrtuple*) (buffer + idx); + r_tuple_first = move_and_align(buffer, nameLen + 1, &idx); for (i = 0; i < naddr; i++) { int family = addr[i].af; - r_tuple = (struct gaih_addrtuple*) (buffer + idx); + r_tuple = move_and_align(buffer, 0, &idx); if (i == naddr - 1) r_tuple->next = NULL; else - r_tuple->next = (struct gaih_addrtuple*) ((char*) r_tuple + ALIGN(sizeof(struct gaih_addrtuple))); + r_tuple->next = move_and_align(buffer, sizeof(struct gaih_addrtuple), &idx); r_tuple->name = r_name; r_tuple->family = family; r_tuple->scopeid = 0; memcpy(r_tuple->addr, addr[i].addr, FAMILY_ADDRESS_SIZE(family)); - idx += ALIGN(sizeof(struct gaih_addrtuple)); } /* At this point, idx == need */ -- 2.7.3