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/* ISC license. */
#include <string.h>
#include <stdint.h>
#include <sys/stat.h>
#include <errno.h>
#include <unistd.h>
#include <skalibs/bytestr.h>
#include <skalibs/types.h>
#include <skalibs/cdb.h>
#include <skalibs/strerr.h>
#include <skalibs/djbunix.h>
#define USAGE "s6-accessrules-fs-from-cdb dir cdbfile"
static char const *basedir ;
size_t basedirlen ;
static void cleanup ()
{
int e = errno ;
rm_rf(basedir) ;
errno = e ;
}
static int domkdir (char const *s)
{
return mkdir(s, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH | S_ISGID) < 0 ? errno == EEXIST : 1 ;
}
static void mkdirp (char *s)
{
mode_t m = umask(0) ;
size_t len = strlen(s) ;
size_t i = basedirlen + 1 ;
for (; i < len ; i++) if (s[i] == '/')
{
s[i] = 0 ;
if (!domkdir(s)) goto err ;
s[i] = '/' ;
}
if (!domkdir(s)) goto err ;
umask(m) ;
return ;
err:
cleanup() ;
strerr_diefu2sys(111, "mkdir ", s) ;
}
static void touchtrunc (char const *file)
{
int fd = open_trunc(file) ;
if (fd < 0)
{
cleanup() ;
strerr_diefu2sys(111, "open_trunc ", file) ;
}
fd_close(fd) ;
}
static int doenv (char const *dir, size_t dirlen, char const *env, uint32_t envlen)
{
mode_t m = umask(0) ;
size_t i = 0 ;
if (!domkdir(dir))
{
cleanup() ;
strerr_diefu2sys(111, "mkdir ", dir) ;
}
umask(m) ;
while (i < envlen)
{
size_t n = byte_chr(env + i, envlen - i, 0) ;
if (i + n >= envlen) return 0 ;
{
size_t p = byte_chr(env + i, n, '=') ;
char tmp[dirlen + p + 2] ;
memcpy(tmp, dir, dirlen) ;
tmp[dirlen] = '/' ;
memcpy(tmp + dirlen + 1, env + i, p) ;
tmp[dirlen + p + 1] = 0 ;
if (p < n)
{
struct iovec v[2] = { { .iov_base = (char *)env + i + p + 1, .iov_len = n - p - 1 }, { .iov_base = "\n", .iov_len = 1 } } ;
if (!openwritevnclose_unsafe(tmp, v, 2))
{
cleanup() ;
strerr_diefu2sys(111, "openwritenclose_unsafe ", tmp) ;
}
}
else touchtrunc(tmp) ;
}
i += n + 1 ;
}
return 1 ;
}
static int doit (char const *key, uint32_t klen, char const *data, uint32_t dlen)
{
uint16_t envlen, execlen ;
char name[basedirlen + klen + 8] ;
if (!dlen || (dlen > 8201)) return 0 ;
memcpy(name, basedir, basedirlen) ;
name[basedirlen] = '/' ;
memcpy(name + basedirlen + 1, key, klen) ;
name[basedirlen + 1 + klen] = 0 ;
mkdirp(name) ;
name[basedirlen + 1 + klen] = '/' ;
if (data[0] == 'A')
{
memcpy(name + basedirlen + klen + 2, "allow", 6) ;
touchtrunc(name) ;
}
else if (data[0] == 'D')
{
memcpy(name + basedirlen + klen + 2, "deny", 5) ;
touchtrunc(name) ;
}
if (dlen < 3) return 1 ;
uint16_unpack_big(data + 1, &envlen) ;
if ((envlen > 4096U) || (3U + envlen > dlen)) return 0 ;
uint16_unpack_big(data + 3 + envlen, &execlen) ;
if ((execlen > 4096U) || (5U + envlen + execlen != dlen)) return 0 ;
if (envlen)
{
memcpy(name + basedirlen + klen + 2, "env", 4) ;
if (!doenv(name, basedirlen + klen + 5, data + 3, envlen)) return 0 ;
}
if (execlen)
{
memcpy(name + basedirlen + klen + 2, "exec", 5) ;
if (!openwritenclose_unsafe(name, data + 5 + envlen, execlen))
{
cleanup() ;
strerr_diefu2sys(111, "openwritenclose_unsafe ", name) ;
}
}
return 1 ;
}
int main (int argc, char const *const *argv)
{
cdb c = CDB_ZERO ;
uint32_t pos = CDB_TRAVERSE_INIT() ;
PROG = "s6-accessrules-fs-from-cdb" ;
if (argc < 3) strerr_dieusage(100, USAGE) ;
if (!cdb_init(&c, argv[2])) strerr_diefu1sys(111, "cdb_init") ;
basedir = argv[1] ;
basedirlen = strlen(argv[1]) ;
{
mode_t m = umask(0) ;
if (mkdir(basedir, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH | S_ISGID) < 0)
strerr_diefu2sys(111, "mkdir ", basedir) ;
umask(m) ;
}
for (;;)
{
cdb_data key, data ;
int r = cdb_traverse_next(&c, &key, &data, &pos) ;
if (r < 0)
{
cleanup() ;
strerr_diefu1x(111, "cdb_traverse_next: invalid cdb") ;
}
else if (!r) break ;
else if (!doit(key.s, key.len, data.s, data.len))
{
cleanup() ;
strerr_diefu3x(111, "handle cdb record: ", argv[2], " does not contain valid accessrules data") ;
}
}
return 0 ;
}
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