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/* ISC license. */
#include <skalibs/bsdsnowflake.h>
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
#include <skalibs/stat.h>
#include <skalibs/posixplz.h>
#include <skalibs/uint16.h>
#include <skalibs/buffer.h>
#include <skalibs/cdb.h>
#include <skalibs/cdbmake.h>
#include <skalibs/stralloc.h>
#include <skalibs/djbtime.h>
#include <skalibs/djbunix.h>
#include <smtpd-starttls-proxy/config.h>
#include "qmailr.h"
/*
qmail-remote uses a "constmap" for smtproutes, which is
basically a cdb in RAM. Every instance of qmail-remote
parses control/smtproutes to make the constmap.
We replace it with a real cdb, stored in the filesystem.
It saves CPU (N-1 instances of qmail-remote use the cdb
directly) and RAM (the cdb is read-only and shared).
The cdb is updated whenever control/smtproutes is newer.
We have to lock around the test to avoid several
concurrent compilations; the lock feels a bit too big,
the crit section can probably be made smaller, but the
current behaviour is safe and avoids retry heuristics.
*/
/*
Key to the control/smtproutes parser:
0 1 2 3 4 5
st\ev EOF # \n : 0-9 other
0 h n n
START END COMMENT START RELAY HOST HOST
1
COMMENT END COMMENT START COMMENT COMMENT COMMENT
2 n h n n
HOST X HOST X RELAY HOST HOST
3 ra n ra r n n
RELAY END RELAY START PORT RELAY RELAY
4 pa pa n
PORT END X START X PORT X
END=5, X=6
0x08 n push character
0x10 h compute host length
0x20 r compute relay length
0x40 p compute port
0x80 a add route entry
*/
static inline uint8_t cclass (char c)
{
switch (c)
{
case 0 : return 0 ;
case '#' : return 1 ;
case '\n' : return 2 ;
case ':' : return 3 ;
case '0' :
case '1' :
case '2' :
case '3' :
case '4' :
case '5' :
case '6' :
case '7' :
case '8' :
case '9' : return 4 ;
default : break ;
}
return 5 ;
}
static inline char getnext (buffer *b)
{
char c ;
ssize_t r = buffer_get(b, &c, 1) ;
if (r == -1) qmailr_tempsys("unable to read from control/smtproutes") ;
return r ? c : 0 ;
}
static inline void smtproutes_compile (int fdr, int fdw)
{
static uint8_t const table[5][6] =
{
{ 0x05, 0x01, 0x00, 0x13, 0x0a, 0x0a },
{ 0x05, 0x01, 0x00, 0x01, 0x01, 0x01 },
{ 0x06, 0x0a, 0x06, 0x13, 0x0a, 0x0a },
{ 0xa5, 0x0b, 0xa0, 0x24, 0x0b, 0x0b },
{ 0xc5, 0x06, 0xc0, 0x06, 0x0c, 0x06 }
} ;
cdbmaker cm = CDBMAKER_ZERO ;
stralloc sa = STRALLOC_ZERO ;
char buf[2048] ;
buffer b = BUFFER_INIT(&buffer_read, fdr, buf, 2048) ;
uint32_t relaypos = 0, relayend = 0 ;
uint8_t state = 0 ;
if (!cdbmake_start(&cm, fdw)) qmailr_tempsys("Unable to cdbmake_start") ;
while (state < 5)
{
char c = getnext(&b) ;
uint8_t val = table[state][cclass(c)] ;
state = val & 0x07 ;
if (val & 0x08)
{
if (!stralloc_catb(&sa, &c, 1)) qmailr_tempsys("Unable to grow stralloc") ;
}
if (val & 0x10)
{
relaypos = sa.len + 1 ;
if (!stralloc_catb(&sa, "\0\0\31", 3)) qmailr_tempsys("Unable to grow stralloc") ;
}
if (val & 0x20)
{
if (!stralloc_0(&sa)) qmailr_tempsys("Unable to grow stralloc") ;
relayend = sa.len ;
}
if (val & 0x40)
{
uint16_t port ;
if (!stralloc_0(&sa)) qmailr_tempsys("Unable to grow stralloc") ;
if (!uint160_scan(sa.s + relayend, &port)) qmailr_temp("Invalid port in control/smtproutes") ;
uint16_pack_big(sa.s + relaypos, port) ;
}
if (val & 0x80)
{
if (!cdbmake_add(&cm, sa.s, relaypos, sa.s + relaypos, relayend - relaypos))
qmailr_tempsys("Unable to cdbmake_add") ;
sa.len = 0 ;
}
}
if (state != 5) qmailr_temp("Syntax error in control/smtproutes") ;
stralloc_free(&sa) ;
if (!cdbmake_finish(&cm)) qmailr_tempsys("Unable to cdbmake_finish") ;
}
int smtproutes_init (cdb *c)
{
static char const *cdbfile = SMTPD_STARTTLS_PROXY_QMAIL_HOME "/run/qmail-remote/smtproutes.cdb" ;
static char const *lckfile = SMTPD_STARTTLS_PROXY_QMAIL_HOME "/run/qmail-remote/smtproutes.lock" ;
static char const *txtfile = SMTPD_STARTTLS_PROXY_QMAIL_HOME "/control/smtproutes" ;
static size_t const cdblen = sizeof(cdbfile) - 1 ;
int fdl = openc_create(lckfile) ;
if (fdl == -1) qmailr_tempsys("Unable to open run/qmail-remote/smtproutes.lock") ;
if (fd_lock(fdl, 1, 0) == -1) qmailr_tempsys("Unable to lock run/qmail-remote/smtproutes.lock") ;
int fdc = openc_read(cdbfile) ;
if (fdc >= 0)
{
struct stat stc, str ;
if (fstat(fdc, &stc) == -1) qmailr_tempsys("Unable to fstat run/qmail-remote/smtproutes.cdb") ;
if (stat(txtfile, &str) == -1)
{
if (errno != ENOENT) qmailr_tempsys("Unable to fstat control/smtproutes") ;
unlink_void(cdbfile) ;
fd_close(fdc) ;
goto zero ;
}
if (timespec_cmp(&stc.st_mtim, &str.st_mtim) > 0) goto useit ;
fd_close(fdc) ;
}
int fdr = openc_read(txtfile) ;
if (fdr == -1)
{
if (errno != ENOENT) qmailr_tempsys("Unable to open control/smtproutes") ;
goto zero ;
}
{
char tmp[cdblen + 8] ;
memcpy(tmp, cdbfile, cdblen) ;
memcpy(tmp + cdblen, ":XXXXXX", 8) ;
fdc = mkstemp(tmp) ;
if (fdc == -1) qmailr_tempsys("Unable to mkstemp") ;
smtproutes_compile(fdr, fdc) ;
if (lseek(fdc, 0, SEEK_SET) == -1) qmailr_tempsys("Unable to lseek") ;
if (fsync(fdc) == -1) qmailr_tempsys("Unable to fsync run/qmail-remote/smtproutes.cdb") ;
fd_close(fdr) ;
if (rename(tmp, cdbfile) == -1) unlink_void(tmp) ;
}
useit:
if (!cdb_init_fromfd(c, fdc)) qmailr_tempsys("Unable to mmap run/qmail-remote/smtproutes.cdb") ;
fd_close(fdc) ;
fd_close(fdl) ;
return 1 ;
zero:
fd_close(fdl) ;
errno = 0 ;
return 0 ;
}
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