Added config file.
[icmp-dn.git] / nss-icmp.c
index 305573f..b9f1013 100644 (file)
 #include <sys/types.h>
 #include <fcntl.h>
 
+#define CONFIGFILE "/etc/nss-icmp.conf"
+
+struct cache {
+    struct cache *next, *prev;
+    char *addr;
+    socklen_t addrlen;
+    int af;
+    int notfound;
+    char **names;
+};
+
+static int inited = 0;
+static int timeout = -1;
+static int usecache = 1;
+static struct cache *cache = NULL;
+
+static void readconfig(void)
+{
+    FILE *f;
+    char linebuf[1024];
+    char *p, *p2;
+    
+    if((f = fopen(CONFIGFILE, "r")) == NULL)
+       return;
+    
+    while(fgets(linebuf, sizeof(linebuf), f) != NULL) {
+       if(linebuf[0] == '#')
+           continue;
+       if((p = strchr(linebuf, '\n')) != NULL)
+           *p = 0;
+       if((p = strchr(linebuf, ' ')) != NULL) {
+           p2 = p + 1;
+           *p = 0;
+       }
+       if(!strcmp(linebuf, "timeout")) {
+           if(p2 == NULL)
+               continue;
+           timeout = atoi(p2);
+       }
+       if(!strcmp(linebuf, "nocache")) {
+           usecache = 0;
+       }
+    }
+    
+    fclose(f);
+}
+
+static void freecache(struct cache *cc)
+{
+    int i;
+    
+    if(cc->next != NULL)
+       cc->next->prev = cc->prev;
+    if(cc->prev != NULL)
+       cc->prev->next = cc->next;
+    if(cc == cache)
+       cache = cc->next;
+    if(cc->addr != NULL)
+       free(cc->addr);
+    if(cc->names != NULL) {
+       for(i = 0; cc->names[i] != NULL; i++)
+           free(cc->names[i]);
+       free(cc->names);
+    }
+    free(cc);
+}
+
+static void cachenotfound(const void *addr, socklen_t len, int af)
+{
+    struct cache *cc;
+    
+    for(cc = cache; cc != NULL; cc = cc->next) {
+       if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len))
+           break;
+    }
+    if(cc == NULL) {
+       if((cc = malloc(sizeof(*cc))) == NULL)
+           return;
+       memset(cc, 0, sizeof(*cc));
+       if((cc->addr = malloc(len)) == NULL) {
+           freecache(cc);
+           return;
+       }
+       memcpy(cc->addr, addr, len);
+       cc->addrlen = len;
+       cc->af = af;
+       
+       cc->notfound = 1;
+       
+       cc->next = cache;
+       if(cache != NULL)
+           cache->prev = cc;
+       cache = cc;
+    }
+}
+
+static void updatecache(struct hostent *he)
+{
+    int i;
+    struct cache *cc;
+    
+    for(cc = cache; cc != NULL; cc = cc->next) {
+       if((cc->af == he->h_addrtype) && (cc->addrlen == he->h_length) && !memcmp(cc->addr, he->h_addr_list[0], he->h_length))
+           break;
+    }
+    if(cc == NULL) {
+       if((cc = malloc(sizeof(*cc))) == NULL)
+           return;
+       memset(cc, 0, sizeof(*cc));
+       if((cc->addr = malloc(he->h_length)) == NULL) {
+           freecache(cc);
+           return;
+       }
+       memcpy(cc->addr, he->h_addr_list[0], he->h_length);
+       cc->addrlen = he->h_length;
+       cc->af = he->h_addrtype;
+       
+       for(i = 0; he->h_aliases[i] != NULL; i++);
+       if((cc->names = malloc(sizeof(*(cc->names)) * (i + 1))) == NULL) {
+           freecache(cc);
+           return;
+       }
+       memset(cc->names, 0, sizeof(*(cc->names)) * (i + 1));
+       for(i = 0; he->h_aliases[i] != NULL; i++) {
+           if((cc->names[i] = malloc(strlen(he->h_aliases[i]) + 1)) == NULL) {
+               freecache(cc);
+               return;
+           }
+           strcpy(cc->names[i], he->h_aliases[i]);
+       }
+       
+       cc->next = cache;
+       if(cache != NULL)
+           cache->prev = cc;
+       cache = cc;
+    }
+}
+
 enum nss_status _nss_icmp_gethostbyaddr_r(const void *addr, socklen_t len, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop)
 {
-    int ret;
+    int i, ret;
     struct retstruct {
        char *aliaslist[16];
        char *addrlist[2];
@@ -26,6 +164,12 @@ enum nss_status _nss_icmp_gethostbyaddr_r(const void *addr, socklen_t len, int a
     pid_t child;
     int pfd[2];
     int rl;
+    struct cache *cc;
+    
+    if(!inited) {
+       readconfig();
+       inited = 1;
+    }
     
     retbuf = (struct retstruct *)buffer;
     if((buflen < sizeof(*retbuf)) || (len > sizeof(retbuf->retaddr))) {
@@ -34,92 +178,129 @@ enum nss_status _nss_icmp_gethostbyaddr_r(const void *addr, socklen_t len, int a
        return(NSS_STATUS_UNAVAIL);
     }
     
-    ap = (u_int8_t *)addr;
-    if(inet_ntop(af, addr, addrbuf, sizeof(addrbuf)) == NULL) {
-       *errnop = errno;
-       *h_errnop = NETDB_INTERNAL;
-       return(NSS_STATUS_UNAVAIL);
-    }
-    
-    if(pipe(pfd)) {
-       *errnop = errno;
-       *h_errnop = NETDB_INTERNAL;
-       return(NSS_STATUS_UNAVAIL);
-    }
-    /* I honestly don't know if it is considered OK to fork in other
-     * people's programs. We need a SUID worker, though, so there's
-     * little choice that I can see. */
-    if((child = fork()) < 0) {
-       *errnop = errno;
-       *h_errnop = NETDB_INTERNAL;
-       return(NSS_STATUS_UNAVAIL);
-    }
-    
-    if(child == 0) {
-       int i, fd;
-       
-       if((fd = open("/dev/null", O_WRONLY)) < 0)
-           exit(127);
-       close(pfd[0]);
-       dup2(pfd[1], 1);
-       dup2(fd, 2);
-       for(i = 3; i < FD_SETSIZE; i++)
-           close(i);
-       
-       execlp("idnlookup", "idnlookup", addrbuf, NULL);
-       exit(127);
+    for(cc = cache; cc != NULL; cc = cc->next) {
+       if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len))
+           break;
     }
     
-    close(pfd[1]);
-    
-    rl = 0;
-    do {
-       ret = read(pfd[0], addrbuf + rl, sizeof(addrbuf) - rl);
-       if(ret < 0) {
+    if(cc == NULL) {
+       ap = (u_int8_t *)addr;
+       if(inet_ntop(af, addr, addrbuf, sizeof(addrbuf)) == NULL) {
            *errnop = errno;
            *h_errnop = NETDB_INTERNAL;
-           close(pfd[0]);
            return(NSS_STATUS_UNAVAIL);
        }
-       rl += ret;
-       if(rl >= sizeof(addrbuf) - 1) {
-           *errnop = ENOMEM;
+    
+       if(pipe(pfd)) {
+           *errnop = errno;
            *h_errnop = NETDB_INTERNAL;
-           close(pfd[0]);
            return(NSS_STATUS_UNAVAIL);
        }
-    } while(ret != 0);
-    addrbuf[rl] = 0;
-    close(pfd[0]);
-    
-    an = 0;
-    p = addrbuf;
-    p3 = buffer + sizeof(*retbuf);
-    while((p2 = strchr(p, '\n')) != NULL) {
-       *p2 = 0;
-       thislen = p2 - p;
-       if(thislen == 0)
-           continue;
-       if((p3 - buffer) + thislen + 1 > buflen) {
-           *errnop = ENOMEM;
+       /* I honestly don't know if it is considered OK to fork in other
+        * people's programs. We need a SUID worker, though, so there's
+        * little choice that I can see. */
+       if((child = fork()) < 0) {
+           *errnop = errno;
            *h_errnop = NETDB_INTERNAL;
            return(NSS_STATUS_UNAVAIL);
        }
-       memcpy(p3, p, thislen + 1);
-       retbuf->aliaslist[an] = p3;
-       p3 += thislen + 1;
-       p = p2 + 1;
-       if(++an == 16) {
-           *errnop = ENOMEM;
-           *h_errnop = NETDB_INTERNAL;
-           return(NSS_STATUS_UNAVAIL);
+    
+       if(child == 0) {
+           int i, fd;
+           char timeoutbuf[128];
+       
+           if((fd = open("/dev/null", O_WRONLY)) < 0)
+               exit(127);
+           close(pfd[0]);
+           dup2(pfd[1], 1);
+           dup2(fd, 2);
+           for(i = 3; i < FD_SETSIZE; i++)
+               close(i);
+       
+           if(timeout != -1) {
+               snprintf(timeoutbuf, sizeof(timeoutbuf), "%i", timeout);
+               execlp("idnlookup", "idnlookup", "-t", timeoutbuf, addrbuf, NULL);
+           } else {
+               execlp("idnlookup", "idnlookup", addrbuf, NULL);
+           }
+           exit(127);
+       }
+    
+       close(pfd[1]);
+    
+       rl = 0;
+       do {
+           ret = read(pfd[0], addrbuf + rl, sizeof(addrbuf) - rl);
+           if(ret < 0) {
+               *errnop = errno;
+               *h_errnop = NETDB_INTERNAL;
+               close(pfd[0]);
+               return(NSS_STATUS_UNAVAIL);
+           }
+           rl += ret;
+           if(rl >= sizeof(addrbuf) - 1) {
+               *errnop = ENOMEM;
+               *h_errnop = NETDB_INTERNAL;
+               close(pfd[0]);
+               return(NSS_STATUS_UNAVAIL);
+           }
+       } while(ret != 0);
+       addrbuf[rl] = 0;
+       close(pfd[0]);
+    
+       an = 0;
+       p = addrbuf;
+       p3 = buffer + sizeof(*retbuf);
+       while((p2 = strchr(p, '\n')) != NULL) {
+           *p2 = 0;
+           thislen = p2 - p;
+           if(thislen == 0)
+               continue;
+           if((p3 - buffer) + thislen + 1 > buflen) {
+               *errnop = ENOMEM;
+               *h_errnop = NETDB_INTERNAL;
+               return(NSS_STATUS_UNAVAIL);
+           }
+           memcpy(p3, p, thislen + 1);
+           retbuf->aliaslist[an] = p3;
+           p3 += thislen + 1;
+           p = p2 + 1;
+           if(++an == 16) {
+               *errnop = ENOMEM;
+               *h_errnop = NETDB_INTERNAL;
+               return(NSS_STATUS_UNAVAIL);
+           }
+       }
+       if(an == 0) {
+           cachenotfound(addr, len, af);
+           *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */
+           return(NSS_STATUS_NOTFOUND);
+       }
+       retbuf->aliaslist[an] = NULL;
+    } else {
+       if(cc->notfound) {
+           *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */
+           return(NSS_STATUS_NOTFOUND);
+       }
+       
+       p3 = buffer + sizeof(*retbuf);
+       for(i = 0; cc->names[i] != NULL; i++) {
+           thislen = strlen(cc->names[i]);
+           if((p3 - buffer) + thislen + 1 > buflen) {
+               *errnop = ENOMEM;
+               *h_errnop = NETDB_INTERNAL;
+               return(NSS_STATUS_UNAVAIL);
+           }
+           memcpy(p3, cc->names[i], thislen + 1);
+           retbuf->aliaslist[an] = p3;
+           p3 += thislen + 1;
+           if(++an == 16) {
+               *errnop = ENOMEM;
+               *h_errnop = NETDB_INTERNAL;
+               return(NSS_STATUS_UNAVAIL);
+           }
        }
     }
-    if(an == 0) {
-       *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */
-       return(NSS_STATUS_NOTFOUND);
-    }
-    retbuf->aliaslist[an] = NULL;
     
     memcpy(retbuf->retaddr, addr, len);
     retbuf->addrlist[0] = retbuf->retaddr;
@@ -130,6 +311,9 @@ enum nss_status _nss_icmp_gethostbyaddr_r(const void *addr, socklen_t len, int a
     result->h_addrtype = af;
     result->h_length = len;
     
+    if(cc == NULL)
+       updatecache(result);
+    
     *h_errnop = NETDB_SUCCESS;
     return(NSS_STATUS_SUCCESS);
 }