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/* ISC license. */
#include <sys/stat.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/tai.h>
#include <skalibs/djbunix.h>
#include <s6/supervise.h>
static int truncit (char const *s)
{
int fd = open_trunc(s) ;
if (fd < 0) return -1 ;
fd_close(fd) ;
return 0 ;
}
ssize_t s6_dtally_read (char const *sv, s6_dtally_t *tab, size_t max)
{
int e = errno ;
size_t len = strlen(sv) ;
size_t n ;
int fd ;
struct stat st ;
char fn[len + sizeof(S6_DTALLY_FILENAME) + 1] ;
memcpy(fn, sv, len) ;
memcpy(fn + len, "/" S6_DTALLY_FILENAME, sizeof(S6_DTALLY_FILENAME) + 1) ;
fd = open_read(fn) ;
if (fd < 0) return errno == ENOENT ? truncit(fn) : -1 ;
if (fstat(fd, &st) < 0) goto err ;
if (st.st_size % S6_DTALLY_PACK)
{
fd_close(fd) ;
return truncit(fn) ;
}
n = st.st_size / S6_DTALLY_PACK ;
if (n > max) n = max ;
{
char tmp[n ? S6_DTALLY_PACK * n : 1] ;
if (lseek(fd, -(off_t)(n * S6_DTALLY_PACK), SEEK_END) < 0) goto err ;
errno = EPIPE ;
if (allread(fd, tmp, n * S6_DTALLY_PACK) < n * S6_DTALLY_PACK) goto err ;
fd_close(fd) ;
for (size_t i = 0 ; i < n ; i++) s6_dtally_unpack(tmp + i * S6_DTALLY_PACK, tab + i) ;
}
errno = e ;
return n ;
err:
fd_close(fd) ;
return -1 ;
}
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