X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=secnet.git;a=blobdiff_plain;f=util.c;h=6742dad52de4d000b3b2476040c1dd2cca148aaa;hp=480f6bce64915c641b7c17ca4fcf68e36daf1aee;hb=94ca562bb14422940ff1986ce8dfca87c222cb59;hpb=b2a56f7c93d221607864761c590952b9a614dc9f

diff --git a/util.c b/util.c
index 480f6bc..6742dad 100644
--- a/util.c
+++ b/util.c
@@ -32,453 +32,70 @@
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>
-#include <syslog.h>
 #include <unistd.h>
 #include <limits.h>
 #include <assert.h>
 #include <sys/wait.h>
-#include <time.h>
+#include <adns.h>
 #include "util.h"
 #include "unaligned.h"
+#include "magic.h"
+#include "ipaddr.h"
 
 #define MIN_BUFFER_SIZE 64
 #define DEFAULT_BUFFER_SIZE 4096
 #define MAX_BUFFER_SIZE 131072
 
-static char *hexdigits="0123456789abcdef";
+static const char *hexdigits="0123456789abcdef";
 
-bool_t secnet_is_daemon=False;
-uint32_t message_level=M_WARNING|M_ERROR|M_SECURITY|M_FATAL;
-struct log_if *system_log=NULL;
-static uint32_t current_phase=0;
+uint32_t current_phase=0;
 
 struct phase_hook {
     hook_fn *fn;
     void *state;
-    struct phase_hook *next;
+    LIST_ENTRY(phase_hook) entry;
 };
 
-static struct phase_hook *hooks[NR_PHASES]={NULL,};
+static LIST_HEAD(, phase_hook) hooks[NR_PHASES];
 
-static void vMessage(uint32_t class, char *message, va_list args)
-{
-    FILE *dest=stdout;
-#define MESSAGE_BUFLEN 1023
-    static char buff[MESSAGE_BUFLEN+1]={0,};
-    uint32_t bp;
-    char *nlp;
-
-    if (secnet_is_daemon) {
-	/* Messages go to the system log interface */
-	bp=strlen(buff);
-	vsnprintf(buff+bp,MESSAGE_BUFLEN-bp,message,args);
-	/* Each line is sent separately */
-	while ((nlp=strchr(buff,'\n'))) {
-	    *nlp=0;
-	    log(system_log,class,buff);
-	    memmove(buff,nlp+1,strlen(nlp+1)+1);
-	}
-    } else {
-	/* Messages go to stdout/stderr */
-	if (class & message_level) {
-	    if (class&M_FATAL || class&M_ERROR || class&M_WARNING) {
-		dest=stderr;
-	    }
-	    vfprintf(dest,message,args);
-	}
-    }
-}  
-
-void Message(uint32_t class, char *message, ...)
-{
-    va_list ap;
-
-    va_start(ap,message);
-    vMessage(class,message,ap);
-    va_end(ap);
-}
-
-static void vfatal(int status, bool_t perror, char *message, va_list args)
-{
-    int err;
-
-    err=errno;
-
-    enter_phase(PHASE_SHUTDOWN);
-    if (perror) {
-	Message(M_FATAL, "secnet fatal error: ");
-	vMessage(M_FATAL, message, args);
-	Message(M_FATAL, ": %s\n",strerror(err));
-    }
-    else {
-	Message(M_FATAL, "secnet fatal error: ");
-	vMessage(M_FATAL,message,args);
-    }
-    exit(status);
-}
-
-void fatal(char *message, ...)
-{
-    va_list args;
-    va_start(args,message);
-    vfatal(current_phase,False,message,args);
-    va_end(args);
-}
-
-void fatal_status(int status, char *message, ...)
-{
-    va_list args;
-    va_start(args,message);
-    vfatal(status,False,message,args);
-    va_end(args);
-}
-
-void fatal_perror(char *message, ...)
-{
-    va_list args;
-    va_start(args,message);
-    vfatal(current_phase,True,message,args);
-    va_end(args);
-}
-
-void fatal_perror_status(int status, char *message, ...)
-{
-    va_list args;
-    va_start(args,message);
-    vfatal(status,True,message,args);
-    va_end(args);
-}
-
-void cfgfatal(struct cloc loc, string_t facility, char *message, ...)
-{
-    va_list args;
-
-    va_start(args,message);
-
-    enter_phase(PHASE_SHUTDOWN);
-
-    if (loc.file && loc.line) {
-	Message(M_FATAL, "config error (%s, %s:%d): ",facility,loc.file,
-		loc.line);
-    } else if (!loc.file && loc.line) {
-	Message(M_FATAL, "config error (%s, line %d): ",facility,loc.line);
-    } else {
-	Message(M_FATAL, "config error (%s): ",facility);
-    }
-    
-    vMessage(M_FATAL,message,args);
-    va_end(args);
-    exit(current_phase);
-}
-
-/* Take a list of log closures and merge them */
-struct loglist {
-    struct log_if *l;
-    struct loglist *next;
-};
-
-static void log_vmulti(void *sst, int class, char *message, va_list args)
-{
-    struct loglist *st=sst, *i;
-
-    if (secnet_is_daemon) {
-	for (i=st; i; i=i->next) {
-	    i->l->vlog(i->l->st,class,message,args);
-	}
-    } else {
-	vMessage(class,message,args);
-	Message(class,"\n");
-    }
-}
-
-static void log_multi(void *st, int priority, char *message, ...)
-{
-    va_list ap;
-
-    va_start(ap,message);
-    log_vmulti(st,priority,message,ap);
-    va_end(ap);
-}
-
-struct log_if *init_log(list_t *ll)
-{
-    int i=0;
-    item_t *item;
-    closure_t *cl;
-    struct loglist *l=NULL, *n;
-    struct log_if *r;
-
-    if (list_length(ll)==1) {
-	item=list_elem(ll,0);
-	cl=item->data.closure;
-	if (cl->type!=CL_LOG) {
-	    cfgfatal(item->loc,"init_log","closure is not a logger");
-	}
-	return cl->interface;
-    }
-    while ((item=list_elem(ll,i++))) {
-	if (item->type!=t_closure) {
-	    cfgfatal(item->loc,"init_log","item is not a closure");
-	}
-	cl=item->data.closure;
-	if (cl->type!=CL_LOG) {
-	    cfgfatal(item->loc,"init_log","closure is not a logger");
-	}
-	n=safe_malloc(sizeof(*n),"init_log");
-	n->l=cl->interface;
-	n->next=l;
-	l=n;
-    }
-    if (!l) {
-	fatal("init_log: no log");
-    }
-    r=safe_malloc(sizeof(*r), "init_log");
-    r->st=l;
-    r->log=log_multi;
-    r->vlog=log_vmulti;
-    return r;
-}
-
-struct logfile {
-    closure_t cl;
-    struct log_if ops;
-    struct cloc loc;
-    string_t logfile;
-    uint32_t level;
-    FILE *f;
-};
-
-static string_t months[]={
-    "Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"};
-
-static void logfile_vlog(void *sst, int class, char *message, va_list args)
-{
-    struct logfile *st=sst;
-    time_t t;
-    struct tm *tm;
-
-    if (secnet_is_daemon) {
-	if (class&st->level) {
-	    t=time(NULL);
-	    tm=localtime(&t);
-	    fprintf(st->f,"%s %2d %02d:%02d:%02d ",
-		    months[tm->tm_mon],tm->tm_mday,tm->tm_hour,tm->tm_min,
-		    tm->tm_sec);
-	    vfprintf(st->f,message,args);
-	    fprintf(st->f,"\n");
-	    fflush(st->f);
-	}
-    } else {
-	vMessage(class,message,args);
-	Message(class,"\n");
-    }
-}
-
-static void logfile_log(void *state, int priority, char *message, ...)
-{
-    va_list ap;
-
-    va_start(ap,message);
-    logfile_vlog(state,priority,message,ap);
-    va_end(ap);
-}
-
-static void logfile_phase_hook(void *sst, uint32_t new_phase)
-{
-    struct logfile *st=sst;
-    FILE *f;
-
-    if (background) {
-	f=fopen(st->logfile,"a");
-	if (!f) fatal_perror("logfile (%s:%d): cannot open \"%s\"",
-			     st->loc.file,st->loc.line,st->logfile);
-	st->f=f;
-    }
-}
-
-static struct flagstr message_class_table[]={
-    { "debug-config", M_DEBUG_CONFIG },
-    { "debug-phase", M_DEBUG_PHASE },
-    { "debug", M_DEBUG },
-    { "all-debug", M_DEBUG|M_DEBUG_PHASE|M_DEBUG_CONFIG },
-    { "info", M_INFO },
-    { "notice", M_NOTICE },
-    { "warning", M_WARNING },
-    { "error", M_ERROR },
-    { "security", M_SECURITY },
-    { "fatal", M_FATAL },
-    { "default", M_WARNING|M_ERROR|M_SECURITY|M_FATAL },
-    { "verbose", M_INFO|M_NOTICE|M_WARNING|M_ERROR|M_SECURITY|M_FATAL },
-    { "quiet", M_FATAL },
-    { NULL, 0 }
-};
-
-static list_t *logfile_apply(closure_t *self, struct cloc loc, dict_t *context,
-			     list_t *args)
-{
-    struct logfile *st;
-    item_t *item;
-    dict_t *dict;
-
-    /* We should defer opening the logfile until the getresources
-       phase.  We should defer writing into the logfile until after we
-       become a daemon. */
-    
-    st=safe_malloc(sizeof(*st),"logfile_apply");
-    st->cl.description="logfile";
-    st->cl.type=CL_LOG;
-    st->cl.apply=NULL;
-    st->cl.interface=&st->ops;
-    st->ops.st=st;
-    st->ops.log=logfile_log;
-    st->ops.vlog=logfile_vlog;
-    st->loc=loc;
-    st->f=stderr;
-
-    item=list_elem(args,0);
-    if (!item || item->type!=t_dict) {
-	cfgfatal(loc,"logfile","argument must be a dictionary\n");
-    }
-    dict=item->data.dict;
-
-    st->logfile=dict_read_string(dict,"filename",True,"logfile",loc);
-    st->level=string_list_to_word(dict_lookup(dict,"class"),
-				       message_class_table,"logfile");
-
-    add_hook(PHASE_GETRESOURCES,logfile_phase_hook,st);
-
-    return new_closure(&st->cl);
-}
-
-struct syslog {
-    closure_t cl;
-    struct log_if ops;
-    string_t ident;
-    int facility;
-    bool_t open;
-};
-
-static int msgclass_to_syslogpriority(uint32_t m)
-{
-    switch (m) {
-    case M_DEBUG_CONFIG: return LOG_DEBUG;
-    case M_DEBUG_PHASE: return LOG_DEBUG;
-    case M_DEBUG: return LOG_DEBUG;
-    case M_INFO: return LOG_INFO;
-    case M_NOTICE: return LOG_NOTICE;
-    case M_WARNING: return LOG_WARNING;
-    case M_ERROR: return LOG_ERR;
-    case M_SECURITY: return LOG_CRIT;
-    case M_FATAL: return LOG_EMERG;
-    default: return LOG_NOTICE;
-    }
-}
-    
-static void syslog_vlog(void *sst, int class, char *message,
-			 va_list args)
-{
-    struct syslog *st=sst;
-
-    if (st->open)
-	vsyslog(msgclass_to_syslogpriority(class),message,args);
-    else {
-	vMessage(class,message,args);
-	Message(class,"\n");
-    }
-}
-
-static void syslog_log(void *sst, int priority, char *message, ...)
-{
-    va_list ap;
-
-    va_start(ap,message);
-    syslog_vlog(sst,priority,message,ap);
-    va_end(ap);
-}
-
-static struct flagstr syslog_facility_table[]={
-    { "authpriv", LOG_AUTHPRIV },
-    { "cron", LOG_CRON },
-    { "daemon", LOG_DAEMON },
-    { "kern", LOG_KERN },
-    { "local0", LOG_LOCAL0 },
-    { "local1", LOG_LOCAL1 },
-    { "local2", LOG_LOCAL2 },
-    { "local3", LOG_LOCAL3 },
-    { "local4", LOG_LOCAL4 },
-    { "local5", LOG_LOCAL5 },
-    { "local6", LOG_LOCAL6 },
-    { "local7", LOG_LOCAL7 },
-    { "lpr", LOG_LPR },
-    { "mail", LOG_MAIL },
-    { "news", LOG_NEWS },
-    { "syslog", LOG_SYSLOG },
-    { "user", LOG_USER },
-    { "uucp", LOG_UUCP },
-    { NULL, 0 }
-};
-
-static void syslog_phase_hook(void *sst, uint32_t newphase)
-{
-    struct syslog *st=sst;
-
-    if (background) {
-	openlog(st->ident,0,st->facility);
-	st->open=True;
-    }
-}
-
-static list_t *syslog_apply(closure_t *self, struct cloc loc, dict_t *context,
-			    list_t *args)
-{
-    struct syslog *st;
-    dict_t *d;
-    item_t *item;
-    string_t facstr;
-
-    st=safe_malloc(sizeof(*st),"syslog_apply");
-    st->cl.description="syslog";
-    st->cl.type=CL_LOG;
-    st->cl.apply=NULL;
-    st->cl.interface=&st->ops;
-    st->ops.st=st;
-    st->ops.log=syslog_log;
-    st->ops.vlog=syslog_vlog;
-
-    item=list_elem(args,0);
-    if (!item || item->type!=t_dict)
-	cfgfatal(loc,"syslog","parameter must be a dictionary\n");
-    d=item->data.dict;
-
-    st->ident=dict_read_string(d, "ident", False, "syslog", loc);
-    facstr=dict_read_string(d, "facility", True, "syslog", loc);
-    st->facility=string_to_word(facstr,loc,
-				syslog_facility_table,"syslog");
-    st->open=False;
-    add_hook(PHASE_GETRESOURCES,syslog_phase_hook,st);
-
-    return new_closure(&st->cl);
-}    
-
-char *safe_strdup(char *s, char *message)
+char *safe_strdup(const char *s, const char *message)
 {
     char *d;
     d=strdup(s);
     if (!d) {
-	fatal_perror(message);
+	fatal_perror("%s",message);
     }
     return d;
 }
 
-void *safe_malloc(size_t size, char *message)
+void *safe_malloc(size_t size, const char *message)
 {
     void *r;
+    if (!size)
+	return 0;
     r=malloc(size);
     if (!r) {
-	fatal_perror(message);
+	fatal_perror("%s",message);
     }
     return r;
 }
+void *safe_realloc_ary(void *p, size_t size, size_t count,
+		       const char *message) {
+    if (count >= INT_MAX/size) {
+	fatal("array allocation overflow: %s", message);
+    }
+    assert(size && count);
+    p = realloc(p, size*count);
+    if (!p)
+	fatal_perror("%s", message);
+    return p;
+}
+
+void *safe_malloc_ary(size_t size, size_t count, const char *message) {
+    if (!size || !count)
+	return 0;
+    return safe_realloc_ary(0,size,count,message);
+}
 
 /* Convert a buffer into its MP_INT representation */
 void read_mpbin(MP_INT *a, uint8_t *bin, int binsize)
@@ -538,7 +155,7 @@ static uint8_t hexval(uint8_t c)
 }
 
 /* Convert a MP_INT into a buffer; return length; truncate if necessary */
-uint32_t write_mpbin(MP_INT *a, uint8_t *buffer, uint32_t buflen)
+int32_t write_mpbin(MP_INT *a, uint8_t *buffer, int32_t buflen)
 {
     char *hb;
     int i,j,l;
@@ -560,160 +177,94 @@ uint32_t write_mpbin(MP_INT *a, uint8_t *buffer, uint32_t buflen)
     return i;
 }
 
-bool_t subnet_match(struct subnet *s, uint32_t address)
-{
-    return (s->prefix==(address&s->mask));
-}
-
-bool_t subnet_matches_list(struct subnet_list *list, uint32_t address)
-{
-    uint32_t i;
-    for (i=0; i<list->entries; i++) {
-	if (list->list[i].prefix == (address&list->list[i].mask)) return True;
-    }
-    return False;
-}
-
-bool_t subnets_intersect(struct subnet a, struct subnet b)
-{
-    uint32_t mask=a.mask&b.mask;
-    return ((a.prefix&mask)==(b.prefix&mask));
-}
-
-bool_t subnet_intersects_with_list(struct subnet a, struct subnet_list *b)
-{
-    uint32_t i;
-
-    for (i=0; i<b->entries; i++) {
-	if (subnets_intersect(a,b->list[i])) return True;
-    }
-    return False;
-}
-
-bool_t subnet_lists_intersect(struct subnet_list *a, struct subnet_list *b)
-{
-    uint32_t i;
-    for (i=0; i<a->entries; i++) {
-	if (subnet_intersects_with_list(a->list[i],b)) return True;
-    }
-    return False;
-}
-
-/* The string buffer must be at least 16 bytes long */
-string_t ipaddr_to_string(uint32_t addr)
-{
-    uint8_t a,b,c,d;
-    string_t s;
-
-    s=safe_malloc(16,"ipaddr_to_string");
-    a=addr>>24;
-    b=addr>>16;
-    c=addr>>8;
-    d=addr;
-    snprintf(s, 16, "%d.%d.%d.%d", a, b, c, d);
-    return s;
-}
-
-string_t subnet_to_string(struct subnet *sn)
-{
-    uint32_t mask=sn->mask, addr=sn->prefix;
-    uint8_t a,b,c,d;
-    string_t s;
-    int i;
-
-    s=safe_malloc(19,"subnet_to_string");
-    a=addr>>24;
-    b=addr>>16;
-    c=addr>>8;
-    d=addr;
-    for (i=0; mask; i++) {
-	mask=(mask<<1);
-    }
-    if (i!=sn->len) {
-	fatal("subnet_to_string: invalid subnet structure!\n");
-    }
-    snprintf(s, 19, "%d.%d.%d.%d/%d", a, b, c, d, sn->len);
-    return s;
+#define DEFINE_SETFDFLAG(fn,FL,FLAG)					\
+void fn(int fd) {							\
+    int r=fcntl(fd, F_GET##FL);						\
+    if (r<0) fatal_perror("fcntl(,F_GET" #FL ") failed");		\
+    r=fcntl(fd, F_SET##FL, r|FLAG);					\
+    if (r<0) fatal_perror("fcntl(,F_SET" #FL ",|" #FLAG ") failed");	\
 }
 
-int sys_cmd(const char *path, char *arg, ...)
-{
-    va_list ap;
-    int rv;
-    pid_t c;
-
-    va_start(ap,arg);
-    c=fork();
-    if (c) {
-	/* Parent -> wait for child */
-	waitpid(c,&rv,0);
-    } else if (c==0) {
-	char *args[100];
-	int i;
-	/* Child -> exec command */
-	args[0]=arg;
-	i=1;
-	while ((args[i++]=va_arg(ap,char *)));
-	execvp(path,args);
-	exit(1);
-    } else {
-	/* Error */
-	fatal_perror("sys_cmd(%s,%s,...)");
-    }
+DEFINE_SETFDFLAG(setcloexec,FD,FD_CLOEXEC);
+DEFINE_SETFDFLAG(setnonblock,FL,O_NONBLOCK);
 
-    va_end(ap);
-    return rv;
+void pipe_cloexec(int fd[2]) {
+    int r=pipe(fd);
+    if (r) fatal_perror("pipe");
+    setcloexec(fd[0]);
+    setcloexec(fd[1]);
 }
 
-static char *phases[NR_PHASES]={
+static const char *phases[NR_PHASES]={
     "PHASE_INIT",
     "PHASE_GETOPTS",
     "PHASE_READCONFIG",
     "PHASE_SETUP",
+    "PHASE_DAEMONIZE",
     "PHASE_GETRESOURCES",
     "PHASE_DROPPRIV",
     "PHASE_RUN",
-    "PHASE_SHUTDOWN"
+    "PHASE_SHUTDOWN",
+    "PHASE_CHILDPERSIST"
 };
 
 void enter_phase(uint32_t new_phase)
 {
     struct phase_hook *i;
 
-    if (hooks[new_phase])
+    if (!LIST_EMPTY(&hooks[new_phase]))
 	Message(M_DEBUG_PHASE,"Running hooks for %s...\n", phases[new_phase]);
     current_phase=new_phase;
 
-    for (i=hooks[new_phase]; i; i=i->next)
+    LIST_FOREACH(i, &hooks[new_phase], entry)
 	i->fn(i->state, new_phase);
     Message(M_DEBUG_PHASE,"Now in %s\n",phases[new_phase]);
 }
 
+void phase_hooks_init(void)
+{
+    int i;
+    for (i=0; i<NR_PHASES; i++)
+	LIST_INIT(&hooks[i]);
+}
+
+void clear_phase_hooks(uint32_t phase)
+{
+    struct phase_hook *h, *htmp;
+    LIST_FOREACH_SAFE(h, &hooks[phase], entry, htmp)
+	free(h);
+    LIST_INIT(&hooks[phase]);
+}
+
 bool_t add_hook(uint32_t phase, hook_fn *fn, void *state)
 {
     struct phase_hook *h;
 
-    h=safe_malloc(sizeof(*h),"add_hook");
+    NEW(h);
     h->fn=fn;
     h->state=state;
-    h->next=hooks[phase];
-    hooks[phase]=h;
+    LIST_INSERT_HEAD(&hooks[phase],h,entry);
     return True;
 }
 
 bool_t remove_hook(uint32_t phase, hook_fn *fn, void *state)
 {
-    fatal("remove_hook: not implemented\n");
+    fatal("remove_hook: not implemented");
 
     return False;
 }
 
-void log(struct log_if *lf, int priority, char *message, ...)
+void vslilog(struct log_if *lf, int priority, const char *message, va_list ap)
+{
+    lf->vlogfn(lf->st,priority,message,ap);
+}
+
+void slilog(struct log_if *lf, int priority, const char *message, ...)
 {
     va_list ap;
     
     va_start(ap,message);
-    lf->vlog(lf->st,priority,message,ap);
+    vslilog(lf,priority,message,ap);
     va_end(ap);
 }
 
@@ -722,47 +273,63 @@ struct buffer {
     struct buffer_if ops;
 };
 
-void buffer_assert_free(struct buffer_if *buffer, string_t file, uint32_t line)
+void buffer_assert_free(struct buffer_if *buffer, cstring_t file,
+			int line)
 {
     if (!buffer->free) {
-	fatal("BUF_ASSERT_FREE, %s line %d, owned by %s\n",
-	      file,line,buffer->owner);
+	fprintf(stderr,"secnet: BUF_ASSERT_FREE, %s line %d, owned by %s",
+		file,line,buffer->owner);
+	assert(!"buffer_assert_free failure");
     }
 }
 
-void buffer_assert_used(struct buffer_if *buffer, string_t file, uint32_t line)
+void buffer_assert_used(struct buffer_if *buffer, cstring_t file,
+			int line)
 {
     if (buffer->free) {
-	fatal("BUF_ASSERT_USED, %s line %d, last owned by %s\n",
-	      file,line,buffer->owner);
+	fprintf(stderr,"secnet: BUF_ASSERT_USED, %s line %d, last owned by %s",
+		file,line,buffer->owner);
+	assert(!"buffer_assert_used failure");
     }
 }
 
-void buffer_init(struct buffer_if *buffer, uint32_t max_start_pad)
+void buffer_init(struct buffer_if *buffer, int32_t max_start_pad)
 {
+    assert(max_start_pad<=buffer->alloclen);
     buffer->start=buffer->base+max_start_pad;
     buffer->size=0;
 }
 
-void *buf_append(struct buffer_if *buf, uint32_t amount) {
+void buffer_destroy(struct buffer_if *buf)
+{
+    BUF_ASSERT_FREE(buf);
+    free(buf->base);
+    buf->start=buf->base=0;
+    buf->size=buf->alloclen=0;
+}
+
+void *buf_append(struct buffer_if *buf, int32_t amount) {
     void *p;
+    assert(amount <= buf_remaining_space(buf));
     p=buf->start + buf->size;
     buf->size+=amount;
     return p;
 }
 
-void *buf_prepend(struct buffer_if *buf, uint32_t amount) {
+void *buf_prepend(struct buffer_if *buf, int32_t amount) {
+    assert(amount <= buf->start - buf->base);
     buf->size+=amount;
     return buf->start-=amount;
 }
 
-void *buf_unappend(struct buffer_if *buf, uint32_t amount) {
+void *buf_unappend(struct buffer_if *buf, int32_t amount) {
     if (buf->size < amount) return 0;
     return buf->start+(buf->size-=amount);
 }
 
-void *buf_unprepend(struct buffer_if *buf, uint32_t amount) {
+void *buf_unprepend(struct buffer_if *buf, int32_t amount) {
     void *p;
+    if (buf->size < amount) return 0;
     p=buf->start;
     buf->start+=amount;
     buf->size-=amount;
@@ -771,16 +338,17 @@ void *buf_unprepend(struct buffer_if *buf, uint32_t amount) {
 
 /* Append a two-byte length and the string to the buffer. Length is in
    network byte order. */
-void buf_append_string(struct buffer_if *buf, string_t s)
+void buf_append_string(struct buffer_if *buf, cstring_t s)
 {
-    uint16_t len;
+    size_t len;
 
     len=strlen(s);
+    /* fixme: if string is longer than 65535, result is a corrupted packet */
     buf_append_uint16(buf,len);
-    memcpy(buf_append(buf,len),s,len);
+    BUF_ADD_BYTES(append,buf,s,len);
 }
 
-void buffer_new(struct buffer_if *buf, uint32_t len)
+void buffer_new(struct buffer_if *buf, int32_t len)
 {
     buf->free=True;
     buf->owner=NULL;
@@ -788,11 +356,39 @@ void buffer_new(struct buffer_if *buf, uint32_t len)
     buf->loc.file=NULL;
     buf->loc.line=0;
     buf->size=0;
-    buf->len=len;
+    buf->alloclen=len;
     buf->start=NULL;
     buf->base=safe_malloc(len,"buffer_new");
 }
 
+void buffer_readonly_view(struct buffer_if *buf, const void *data, int32_t len)
+{
+    buf->free=False;
+    buf->owner="READONLY";
+    buf->flags=0;
+    buf->loc.file=NULL;
+    buf->loc.line=0;
+    buf->size=buf->alloclen=len;
+    buf->base=buf->start=(uint8_t*)data;
+}
+
+void buffer_readonly_clone(struct buffer_if *out, const struct buffer_if *in)
+{
+    buffer_readonly_view(out,in->start,in->size);
+}
+
+void buffer_copy(struct buffer_if *dst, const struct buffer_if *src)
+{
+    if (dst->alloclen < src->alloclen) {
+	dst->base=realloc(dst->base,src->alloclen);
+	if (!dst->base) fatal_perror("buffer_copy");
+	dst->alloclen = src->alloclen;
+    }
+    dst->start = dst->base + (src->start - src->base);
+    dst->size = src->size;
+    memcpy(dst->start, src->start, dst->size);
+}
+
 static list_t *buffer_apply(closure_t *self, struct cloc loc, dict_t *context,
 			    list_t *args)
 {
@@ -802,7 +398,7 @@ static list_t *buffer_apply(closure_t *self, struct cloc loc, dict_t *context,
     bool_t lockdown=False;
     uint32_t len=DEFAULT_BUFFER_SIZE;
     
-    st=safe_malloc(sizeof(*st),"buffer_apply");
+    NEW(st);
     st->cl.description="buffer";
     st->cl.type=CL_BUFFER;
     st->cl.apply=NULL;
@@ -843,10 +439,277 @@ static list_t *buffer_apply(closure_t *self, struct cloc loc, dict_t *context,
     return new_closure(&st->cl);
 }
 
-init_module util_module;
+void send_nak(const struct comm_addr *dest, uint32_t our_index,
+	      uint32_t their_index, uint32_t msgtype,
+	      struct buffer_if *buf, const char *logwhy)
+{
+    buffer_init(buf,calculate_max_start_pad());
+    buf_append_uint32(buf,their_index);
+    buf_append_uint32(buf,our_index);
+    buf_append_uint32(buf,LABEL_NAK);
+    if (logwhy)
+	Message(M_INFO,"%s: %08"PRIx32"<-%08"PRIx32": %08"PRIx32":"
+		" %s; sending NAK\n",
+		comm_addr_to_string(dest),
+		our_index, their_index, msgtype, logwhy);
+    dest->comm->sendmsg(dest->comm->st, buf, dest);
+}
+
+int consttime_memeq(const void *s1in, const void *s2in, size_t n)
+{
+    const uint8_t *s1=s1in, *s2=s2in;
+    register volatile uint8_t accumulator=0;
+
+    while (n-- > 0) {
+	accumulator |= (*s1++ ^ *s2++);
+    }
+    accumulator |= accumulator >> 4; /* constant-time             */
+    accumulator |= accumulator >> 2; /*  boolean canonicalisation */
+    accumulator |= accumulator >> 1;
+    accumulator &= 1;
+    accumulator ^= 1;
+    return accumulator;
+}
+
 void util_module(dict_t *dict)
 {
-    add_closure(dict,"logfile",logfile_apply);
-    add_closure(dict,"syslog",syslog_apply);
     add_closure(dict,"sysbuffer",buffer_apply);
 }
+
+void update_max_start_pad(int32_t *our_module_global, int32_t our_instance)
+{
+    if (*our_module_global < our_instance)
+	*our_module_global=our_instance;
+}
+
+int32_t	transform_max_start_pad, comm_max_start_pad;
+
+int32_t calculate_max_start_pad(void)
+{
+    return
+	site_max_start_pad +
+	transform_max_start_pad +
+	comm_max_start_pad;
+}
+
+void vslilog_part(struct log_if *lf, int priority, const char *message, va_list ap)
+{
+    char *buff=lf->buff;
+    size_t bp;
+    char *nlp;
+
+    bp=strlen(buff);
+    assert(bp < LOG_MESSAGE_BUFLEN);
+    vsnprintf(buff+bp,LOG_MESSAGE_BUFLEN-bp,message,ap);
+    buff[LOG_MESSAGE_BUFLEN-1] = '\n';
+    buff[LOG_MESSAGE_BUFLEN] = '\0';
+    /* Each line is sent separately */
+    while ((nlp=strchr(buff,'\n'))) {
+	*nlp=0;
+	slilog(lf,priority,"%s",buff);
+	memmove(buff,nlp+1,strlen(nlp+1)+1);
+    }
+}
+
+extern void slilog_part(struct log_if *lf, int priority, const char *message, ...)
+{
+    va_list ap;
+    va_start(ap,message);
+    vslilog_part(lf,priority,message,ap);
+    va_end(ap);
+}
+
+void string_item_to_iaddr(const item_t *item, uint16_t port, union iaddr *ia,
+			  const char *desc)
+{
+#ifndef CONFIG_IPV6
+
+    ia->sin.sin_family=AF_INET;
+    ia->sin.sin_addr.s_addr=string_item_to_ipaddr(item,desc);
+    ia->sin.sin_port=htons(port);
+
+#else /* CONFIG_IPV6 => we have adns_text2addr */
+
+    if (item->type!=t_string)
+	cfgfatal(item->loc,desc,"expecting a string IP (v4 or v6) address\n");
+    socklen_t salen=sizeof(*ia);
+    int r=adns_text2addr(item->data.string, port,
+			 adns_qf_addrlit_ipv4_quadonly,
+			 &ia->sa, &salen);
+    assert(r!=ENOSPC);
+    if (r) cfgfatal(item->loc,desc,"invalid IP (v4 or v6) address: %s\n",
+		    strerror(r));
+
+#endif /* CONFIG_IPV6 */
+}
+
+#define IADDR_NBUFS 8
+
+const char *iaddr_to_string(const union iaddr *ia)
+{
+#ifndef CONFIG_IPV6
+
+    SBUF_DEFINE(IADDR_NBUFS, 100);
+
+    assert(ia->sa.sa_family == AF_INET);
+
+    snprintf(SBUF, sizeof(SBUF), "[%s]:%d",
+	     inet_ntoa(ia->sin.sin_addr),
+	     ntohs(ia->sin.sin_port));
+
+#else /* CONFIG_IPV6 => we have adns_addr2text */
+
+    SBUF_DEFINE(IADDR_NBUFS, 1+ADNS_ADDR2TEXT_BUFLEN+20);
+
+    int port;
+
+    char *addrbuf = SBUF;
+    *addrbuf++ = '[';
+    int addrbuflen = ADNS_ADDR2TEXT_BUFLEN;
+
+    int r = adns_addr2text(&ia->sa, 0, addrbuf, &addrbuflen, &port);
+    if (r) {
+	const char fmt[]= "scoped IPv6 addr, error: %.*s";
+	sprintf(addrbuf, fmt,
+		(int)(ADNS_ADDR2TEXT_BUFLEN - sizeof(fmt)) /* underestimate */,
+		strerror(r));
+    }
+
+    char *portbuf = addrbuf;
+    int addrl = strlen(addrbuf);
+    portbuf += addrl;
+
+    snprintf(portbuf, sizeof(SBUF)-addrl, "]:%d", port);
+
+#endif /* CONFIG_IPV6 */
+
+    return SBUF;
+}
+
+bool_t iaddr_equal(const union iaddr *ia, const union iaddr *ib,
+		   bool_t ignoreport)
+{
+    if (ia->sa.sa_family != ib->sa.sa_family)
+	return 0;
+    switch (ia->sa.sa_family) {
+    case AF_INET:
+	return ia->sin.sin_addr.s_addr == ib->sin.sin_addr.s_addr
+           && (ignoreport ||
+	       ia->sin.sin_port        == ib->sin.sin_port);
+#ifdef CONFIG_IPV6
+    case AF_INET6:
+	return !memcmp(&ia->sin6.sin6_addr, &ib->sin6.sin6_addr, 16)
+	   &&  ia->sin6.sin6_scope_id  == ib->sin6.sin6_scope_id
+           && (ignoreport ||
+	       ia->sin6.sin6_port      == ib->sin6.sin6_port)
+	    /* we ignore the flowinfo field */;
+#endif /* CONFIG_IPV6 */
+    default:
+	abort();
+    }
+}
+
+int iaddr_socklen(const union iaddr *ia)
+{
+    switch (ia->sa.sa_family) {
+    case AF_INET:  return sizeof(ia->sin);
+#ifdef CONFIG_IPV6
+    case AF_INET6: return sizeof(ia->sin6);
+#endif /* CONFIG_IPV6 */
+    default:       abort();
+    }
+}
+
+const char *pollbadbit(int revents)
+{
+#define BADBIT(b) \
+    if ((revents & b)) return #b
+    BADBIT(POLLERR);
+    BADBIT(POLLHUP);
+    /* POLLNVAL is handled by the event loop - see afterpoll_fn comment */
+#undef BADBIT
+    return 0;
+}
+
+enum async_linebuf_result
+async_linebuf_read(struct pollfd *pfd, struct buffer_if *buf,
+		   const char **emsg_out)
+{
+    int revents=pfd->revents;
+
+#define BAD(m) do{ *emsg_out=(m); return async_linebuf_broken; }while(0)
+
+    const char *badbit=pollbadbit(revents);
+    if (badbit) BAD(badbit);
+
+    if (!(revents & POLLIN))
+	return async_linebuf_nothing;
+
+    /*
+     * Data structure: A line which has been returned to the user is
+     * stored in buf at base before start.  But we retain the usual
+     * buffer meaning of size.  So:
+     *
+     *   | returned :    | input read,   |    unused    |
+     *   |  to user : \0 |  awaiting     |     buffer   |
+     *   |          :    |  processing   |      space   |
+     *   |          :    |               |              |
+     *   ^base           ^start          ^start+size    ^base+alloclen
+     */
+
+    BUF_ASSERT_USED(buf);
+
+    /* firstly, eat any previous */
+    if (buf->start != buf->base) {
+	memmove(buf->base,buf->start,buf->size);
+	buf->start=buf->base;
+    }
+
+    uint8_t *searched=buf->base;
+
+    /*
+     * During the workings here we do not use start.  We set start
+     * when we return some actual data.  So we have this:
+     *
+     *   | searched     | read, might   |  unused      |
+     *   |  for \n      |  contain \n   |   buffer     |
+     *   |  none found  |  but not \0   |    space     |
+     *   |              |               |              |
+     *   ^base          ^searched       ^base+size     ^base+alloclen
+     *  [^start]                        ^dataend
+     *
+     */
+    for (;;) {
+	uint8_t *dataend=buf->base+buf->size;
+	char *newline=memchr(searched,'\n',dataend-searched);
+	if (newline) {
+	    *newline=0;
+	    buf->start=newline+1;
+	    buf->size=dataend-buf->start;
+	    return async_linebuf_ok;
+	}
+	searched=dataend;
+	ssize_t space=(buf->base+buf->alloclen)-dataend;
+	if (!space) BAD("input line too long");
+	ssize_t r=read(pfd->fd,searched,space);
+	if (r==0) {
+	    *searched=0;
+	    *emsg_out=buf->size?"no newline at eof":0;
+	    buf->start=searched+1;
+	    buf->size=0;
+	    return async_linebuf_eof;
+	}
+	if (r<0) {
+	    if (errno==EINTR)
+		continue;
+	    if (iswouldblock(errno))
+		return async_linebuf_nothing;
+	    BAD(strerror(errno));
+	}
+	assert(r<=space);
+	if (memchr(searched,0,r)) BAD("nul in input data");
+	buf->size+=r;
+    }
+
+#undef BAD
+}