minix3/servers/ds/store.c

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C
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2020-02-21 00:59:27 +05:30
#include "inc.h"
#include "store.h"
/* Allocate space for the data store. */
static struct data_store ds_store[NR_DS_KEYS];
static struct subscription ds_subs[NR_DS_SUBS];
/*===========================================================================*
* alloc_data_slot *
*===========================================================================*/
static struct data_store *alloc_data_slot(void)
{
/* Allocate a new data slot. */
int i;
for (i = 0; i < NR_DS_KEYS; i++) {
if (!(ds_store[i].flags & DSF_IN_USE))
return &ds_store[i];
}
return NULL;
}
/*===========================================================================*
* alloc_sub_slot *
*===========================================================================*/
static struct subscription *alloc_sub_slot(void)
{
/* Allocate a new subscription slot. */
int i;
for (i = 0; i < NR_DS_SUBS; i++) {
if (!(ds_subs[i].flags & DSF_IN_USE))
return &ds_subs[i];
}
return NULL;
}
/*===========================================================================*
* lookup_entry *
*===========================================================================*/
static struct data_store *lookup_entry(const char *key_name, int type)
{
/* Lookup an existing entry by key and type. */
int i;
for (i = 0; i < NR_DS_KEYS; i++) {
if ((ds_store[i].flags & DSF_IN_USE) /* used */
&& (ds_store[i].flags & type) /* same type*/
&& !strcmp(ds_store[i].key, key_name)) /* same key*/
return &ds_store[i];
}
return NULL;
}
/*===========================================================================*
* lookup_label_entry *
*===========================================================================*/
static struct data_store *lookup_label_entry(unsigned num)
{
/* Lookup an existing label entry by num. */
int i;
for (i = 0; i < NR_DS_KEYS; i++) {
if ((ds_store[i].flags & DSF_IN_USE)
&& (ds_store[i].flags & DSF_TYPE_LABEL)
&& (ds_store[i].u.u32 == num))
return &ds_store[i];
}
return NULL;
}
/*===========================================================================*
* lookup_sub *
*===========================================================================*/
static struct subscription *lookup_sub(const char *owner)
{
/* Lookup an existing subscription given its owner. */
int i;
for (i = 0; i < NR_DS_SUBS; i++) {
if ((ds_subs[i].flags & DSF_IN_USE) /* used */
&& !strcmp(ds_subs[i].owner, owner)) /* same key*/
return &ds_subs[i];
}
return NULL;
}
/*===========================================================================*
* ds_getprocname *
*===========================================================================*/
static char *ds_getprocname(endpoint_t e)
{
/* Get a process name given its endpoint. */
struct data_store *dsp;
static char *first_proc_name = "ds";
endpoint_t first_proc_ep = DS_PROC_NR;
if(e == first_proc_ep)
return first_proc_name;
if((dsp = lookup_label_entry(e)) != NULL)
return dsp->key;
return NULL;
}
/*===========================================================================*
* ds_getprocep *
*===========================================================================*/
static endpoint_t ds_getprocep(const char *s)
{
/* Get a process endpoint given its name. */
struct data_store *dsp;
if((dsp = lookup_entry(s, DSF_TYPE_LABEL)) != NULL)
return dsp->u.u32;
panic("ds_getprocep: process endpoint not found");
}
/*===========================================================================*
* check_auth *
*===========================================================================*/
static int check_auth(const struct data_store *p, endpoint_t ep, int perm)
{
/* Check authorization for a given type of permission. */
char *source;
if(!(p->flags & perm))
return 1;
source = ds_getprocname(ep);
return source && !strcmp(p->owner, source);
}
/*===========================================================================*
* get_key_name *
*===========================================================================*/
static int get_key_name(const message *m_ptr, char *key_name)
{
/* Get key name given an input message. */
int r;
if (m_ptr->m_ds_req.key_len > DS_MAX_KEYLEN || m_ptr->m_ds_req.key_len < 2) {
printf("DS: bogus key length (%d) from %d\n", m_ptr->m_ds_req.key_len,
m_ptr->m_source);
return EINVAL;
}
/* Copy name from caller. */
r = sys_safecopyfrom(m_ptr->m_source,
(cp_grant_id_t) m_ptr->m_ds_req.key_grant, 0,
(vir_bytes) key_name, m_ptr->m_ds_req.key_len);
if(r != OK) {
printf("DS: publish: copy failed from %d: %d\n", m_ptr->m_source, r);
return r;
}
key_name[DS_MAX_KEYLEN-1] = '\0';
return OK;
}
/*===========================================================================*
* check_sub_match *
*===========================================================================*/
static int check_sub_match(const struct subscription *subp,
struct data_store *dsp, endpoint_t ep)
{
/* Check if an entry matches a subscription. Return 1 in case of match. */
return (check_auth(dsp, ep, DSF_PRIV_SUBSCRIBE)
&& regexec(&subp->regex, dsp->key, 0, NULL, 0) == 0)
? 1 : 0;
}
/*===========================================================================*
* update_subscribers *
*===========================================================================*/
static void update_subscribers(struct data_store *dsp, int set)
{
/* If set = 1, set bit in the sub bitmap of any subscription matching the given
* entry, otherwise clear it. In both cases, notify the subscriber.
*/
int i;
int nr = dsp - ds_store;
endpoint_t ep;
for(i = 0; i < NR_DS_SUBS; i++) {
if(!(ds_subs[i].flags & DSF_IN_USE))
continue;
if(!(ds_subs[i].flags & dsp->flags & DSF_MASK_TYPE))
continue;
ep = ds_getprocep(ds_subs[i].owner);
if(!check_sub_match(&ds_subs[i], dsp, ep))
continue;
if(set == 1) {
SET_BIT(ds_subs[i].old_subs, nr);
} else {
UNSET_BIT(ds_subs[i].old_subs, nr);
}
ipc_notify(ep);
}
}
/*===========================================================================*
* map_service *
*===========================================================================*/
static int map_service(const struct rprocpub *rpub)
{
/* Map a new service by registering its label. */
struct data_store *dsp;
/* Allocate a new data slot. */
if((dsp = alloc_data_slot()) == NULL) {
return ENOMEM;
}
/* Set attributes. */
strcpy(dsp->key, rpub->label);
dsp->u.u32 = (u32_t) rpub->endpoint;
strcpy(dsp->owner, "rs");
dsp->flags = DSF_IN_USE | DSF_TYPE_LABEL;
/* Update subscribers having a matching subscription. */
update_subscribers(dsp, 1);
return(OK);
}
/*===========================================================================*
* sef_cb_init_fresh *
*===========================================================================*/
int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *info)
{
/* Initialize the data store server. */
int i, r;
struct rprocpub rprocpub[NR_BOOT_PROCS];
/* Reset data store: data and subscriptions. */
for(i = 0; i < NR_DS_KEYS; i++) {
ds_store[i].flags = 0;
}
for(i = 0; i < NR_DS_SUBS; i++) {
ds_subs[i].flags = 0;
}
/* Map all the services in the boot image. */
if((r = sys_safecopyfrom(RS_PROC_NR, info->rproctab_gid, 0,
(vir_bytes) rprocpub, sizeof(rprocpub))) != OK) {
panic("sys_safecopyfrom failed: %d", r);
}
for(i=0;i < NR_BOOT_PROCS;i++) {
if(rprocpub[i].in_use) {
if((r = map_service(&rprocpub[i])) != OK) {
panic("unable to map service: %d", r);
}
}
}
return(OK);
}
/*===========================================================================*
* do_publish *
*===========================================================================*/
int do_publish(message *m_ptr)
{
struct data_store *dsp;
char key_name[DS_MAX_KEYLEN];
char *source;
int flags = m_ptr->m_ds_req.flags;
size_t length;
int r;
/* Lookup the source. */
source = ds_getprocname(m_ptr->m_source);
if(source == NULL)
return EPERM;
/* Only RS can publish labels. */
if((flags & DSF_TYPE_LABEL) && m_ptr->m_source != RS_PROC_NR)
return EPERM;
/* Get key name. */
if((r = get_key_name(m_ptr, key_name)) != OK)
return r;
/* Lookup the entry. */
dsp = lookup_entry(key_name, flags & DSF_MASK_TYPE);
/* If type is LABEL, also try to lookup the entry by num. */
if((flags & DSF_TYPE_LABEL) && (dsp == NULL))
dsp = lookup_label_entry(m_ptr->m_ds_req.val_in.ep);
if(dsp == NULL) {
/* The entry doesn't exist, allocate a new data slot. */
if((dsp = alloc_data_slot()) == NULL)
return ENOMEM;
} else if (flags & DSF_OVERWRITE) {
/* Overwrite. */
if(!check_auth(dsp, m_ptr->m_source, DSF_PRIV_OVERWRITE))
return EPERM;
} else {
/* Don't overwrite and return error. */
return EEXIST;
}
/* Store! */
switch(flags & DSF_MASK_TYPE) {
case DSF_TYPE_U32:
dsp->u.u32 = m_ptr->m_ds_req.val_in.u32;
break;
case DSF_TYPE_LABEL:
dsp->u.u32 = m_ptr->m_ds_req.val_in.ep;
break;
case DSF_TYPE_STR:
case DSF_TYPE_MEM:
length = m_ptr->m_ds_req.val_len;
/* Allocate a new data buffer if necessary. */
if(!(dsp->flags & DSF_IN_USE)) {
if((dsp->u.mem.data = malloc(length)) == NULL)
return ENOMEM;
dsp->u.mem.reallen = length;
} else if(length > dsp->u.mem.reallen) {
free(dsp->u.mem.data);
if((dsp->u.mem.data = malloc(length)) == NULL)
return ENOMEM;
dsp->u.mem.reallen = length;
}
/* Copy the memory range. */
r = sys_safecopyfrom(m_ptr->m_source, m_ptr->m_ds_req.val_in.grant,
0, (vir_bytes) dsp->u.mem.data, length);
if(r != OK) {
printf("DS: publish: memory map/copy failed from %d: %d\n",
m_ptr->m_source, r);
free(dsp->u.mem.data);
return r;
}
dsp->u.mem.length = length;
if(flags & DSF_TYPE_STR) {
((char*)dsp->u.mem.data)[length-1] = '\0';
}
break;
default:
return EINVAL;
}
/* Set attributes. */
strcpy(dsp->key, key_name);
strcpy(dsp->owner, source);
dsp->flags = DSF_IN_USE | (flags & DSF_MASK_INTERNAL);
/* Update subscribers having a matching subscription. */
update_subscribers(dsp, 1);
return(OK);
}
/*===========================================================================*
* do_retrieve *
*===========================================================================*/
int do_retrieve(message *m_ptr)
{
struct data_store *dsp;
char key_name[DS_MAX_KEYLEN];
int flags = m_ptr->m_ds_req.flags;
int type = flags & DSF_MASK_TYPE;
size_t length;
int r;
/* Get key name. */
if((r = get_key_name(m_ptr, key_name)) != OK)
return r;
/* Lookup the entry. */
if((dsp = lookup_entry(key_name, type)) == NULL)
return ESRCH;
if(!check_auth(dsp, m_ptr->m_source, DSF_PRIV_RETRIEVE))
return EPERM;
/* Copy the requested data. */
switch(type) {
case DSF_TYPE_U32:
m_ptr->m_ds_reply.val_out.u32 = dsp->u.u32;
break;
case DSF_TYPE_LABEL:
m_ptr->m_ds_reply.val_out.ep = dsp->u.u32;
break;
case DSF_TYPE_STR:
case DSF_TYPE_MEM:
length = MIN(m_ptr->m_ds_req.val_len, dsp->u.mem.length);
r = sys_safecopyto(m_ptr->m_source, m_ptr->m_ds_req.val_in.grant, 0,
(vir_bytes) dsp->u.mem.data, length);
if(r != OK) {
printf("DS: retrieve: copy failed to %d: %d\n",
m_ptr->m_source, r);
return r;
}
m_ptr->m_ds_reply.val_len = length;
break;
default:
return EINVAL;
}
return OK;
}
/*===========================================================================*
* do_retrieve_label *
*===========================================================================*/
int do_retrieve_label(const message *m_ptr)
{
struct data_store *dsp;
int r;
/* Lookup the label entry. */
if((dsp = lookup_label_entry(m_ptr->m_ds_req.val_in.ep)) == NULL)
return ESRCH;
/* Copy the key name. */
r = sys_safecopyto(m_ptr->m_source,
(cp_grant_id_t) m_ptr->m_ds_req.key_grant, (vir_bytes) 0,
(vir_bytes) dsp->key, strlen(dsp->key) + 1);
if(r != OK) {
printf("DS: copy failed from %d: %d\n", m_ptr->m_source, r);
return r;
}
return OK;
}
/*===========================================================================*
* do_subscribe *
*===========================================================================*/
int do_subscribe(message *m_ptr)
{
char regex[DS_MAX_KEYLEN+2];
struct subscription *subp;
char errbuf[80];
char *owner;
int type_set;
int r, e, b;
/* Find the owner. */
owner = ds_getprocname(m_ptr->m_source);
if(owner == NULL)
return ESRCH;
/* See if the owner already has an existing subscription. */
if((subp = lookup_sub(owner)) == NULL) {
/* The subscription doesn't exist, allocate a new one. */
if((subp = alloc_sub_slot()) == NULL)
return EAGAIN;
} else if(!(m_ptr->m_ds_req.flags & DSF_OVERWRITE)) {
/* The subscription exists but we can't overwrite, return error. */
return EEXIST;
}
/* Copy key name from the caller. Anchor the subscription with "^regexp$" so
* substrings don't match. The caller will probably not expect this,
* and the usual case is for a complete match.
*/
regex[0] = '^';
if((r = get_key_name(m_ptr, regex+1)) != OK)
return r;
strcat(regex, "$");
/* Compile regular expression. */
if((e=regcomp(&subp->regex, regex, REG_EXTENDED)) != 0) {
regerror(e, &subp->regex, errbuf, sizeof(errbuf));
printf("DS: subscribe: regerror: %s\n", errbuf);
return EINVAL;
}
/* If type_set = 0, then subscribe all types. */
type_set = m_ptr->m_ds_req.flags & DSF_MASK_TYPE;
if(type_set == 0)
type_set = DSF_MASK_TYPE;
subp->flags = DSF_IN_USE | type_set;
strcpy(subp->owner, owner);
for(b = 0; b < BITMAP_CHUNKS(NR_DS_KEYS); b++)
subp->old_subs[b] = 0;
/* See if caller requested an instant initial list. */
if(m_ptr->m_ds_req.flags & DSF_INITIAL) {
int i, match_found = FALSE;
for(i = 0; i < NR_DS_KEYS; i++) {
if(!(ds_store[i].flags & DSF_IN_USE))
continue;
if(!(ds_store[i].flags & type_set))
continue;
if(!check_sub_match(subp, &ds_store[i], m_ptr->m_source))
continue;
SET_BIT(subp->old_subs, i);
match_found = TRUE;
}
/* Notify in case of match. */
if(match_found)
ipc_notify(m_ptr->m_source);
}
return OK;
}
/*===========================================================================*
* do_check *
*===========================================================================*/
int do_check(message *m_ptr)
{
struct subscription *subp;
char *owner;
endpoint_t entry_owner_e;
int r, i;
/* Find the subscription owner. */
owner = ds_getprocname(m_ptr->m_source);
if(owner == NULL)
return ESRCH;
/* Lookup the owner's subscription. */
if((subp = lookup_sub(owner)) == NULL)
return ESRCH;
/* Look for an updated entry the subscriber is interested in. */
for(i = 0; i < NR_DS_KEYS; i++) {
if(GET_BIT(subp->old_subs, i))
break;
}
if(i == NR_DS_KEYS)
return ENOENT;
/* Copy the key name. */
r = sys_safecopyto(m_ptr->m_source,
(cp_grant_id_t) m_ptr->m_ds_req.key_grant, (vir_bytes) 0,
(vir_bytes) ds_store[i].key, strlen(ds_store[i].key) + 1);
if(r != OK) {
printf("DS: check: copy failed from %d: %d\n", m_ptr->m_source, r);
return r;
}
/* Copy the type and the owner of the original entry. */
entry_owner_e = ds_getprocep(ds_store[i].owner);
m_ptr->m_ds_req.flags = ds_store[i].flags & DSF_MASK_TYPE;
m_ptr->m_ds_req.owner = entry_owner_e;
/* Mark the entry as no longer updated for the subscriber. */
UNSET_BIT(subp->old_subs, i);
return OK;
}
/*===========================================================================*
* do_delete *
*===========================================================================*/
int do_delete(message *m_ptr)
{
struct data_store *dsp;
char key_name[DS_MAX_KEYLEN];
char *source;
char *label;
int type = m_ptr->m_ds_req.flags & DSF_MASK_TYPE;
int i, r;
/* Lookup the source. */
source = ds_getprocname(m_ptr->m_source);
if(source == NULL)
return EPERM;
/* Get key name. */
if((r = get_key_name(m_ptr, key_name)) != OK)
return r;
/* Lookup the entry. */
if((dsp = lookup_entry(key_name, type)) == NULL)
return ESRCH;
/* Only the owner can delete. */
if(strcmp(dsp->owner, source))
return EPERM;
switch(type) {
case DSF_TYPE_U32:
break;
case DSF_TYPE_LABEL:
label = dsp->key;
/* Clean up subscriptions. */
for (i = 0; i < NR_DS_SUBS; i++) {
if ((ds_subs[i].flags & DSF_IN_USE)
&& !strcmp(ds_subs[i].owner, label)) {
ds_subs[i].flags = 0;
}
}
/* Clean up data entries. */
for (i = 0; i < NR_DS_KEYS; i++) {
if ((ds_store[i].flags & DSF_IN_USE)
&& !strcmp(ds_store[i].owner, label)) {
update_subscribers(&ds_store[i], 0);
ds_store[i].flags = 0;
}
}
break;
case DSF_TYPE_STR:
case DSF_TYPE_MEM:
free(dsp->u.mem.data);
break;
default:
return EINVAL;
}
/* Update subscribers having a matching subscription. */
update_subscribers(dsp, 0);
/* Clear the entry. */
dsp->flags = 0;
return OK;
}
/*===========================================================================*
* do_getsysinfo *
*===========================================================================*/
int do_getsysinfo(const message *m_ptr)
{
vir_bytes src_addr;
size_t length;
int s;
switch(m_ptr->m_lsys_getsysinfo.what) {
case SI_DATA_STORE:
src_addr = (vir_bytes)ds_store;
length = sizeof(struct data_store) * NR_DS_KEYS;
break;
default:
return EINVAL;
}
if (length != m_ptr->m_lsys_getsysinfo.size)
return EINVAL;
if (OK != (s=sys_datacopy(SELF, src_addr,
m_ptr->m_source, m_ptr->m_lsys_getsysinfo.where, length))) {
printf("DS: copy failed: %d\n", s);
return s;
}
return OK;
}