R_API const char * r_magic_buffer(RMagic *ms, const void *buf, size_t nb) {
if (file_reset (ms) == -1)
return NULL;
/*
* The main work is done here!
* We have the file name and/or the data buffer to be identified.
*/
if (file_buffer (ms, -1, NULL, buf, nb) == -1)
return NULL;
return file_getbuffer (ms);
}
static const char *file_or_fd(RMagic *ms, const char *inname, int fd) {
int ispipe = 0, rv = -1;
unsigned char *buf;
struct stat sb;
int nbytes = 0; /* number of bytes read from a datafile */
/*
* one extra for terminating '\0', and
* some overlapping space for matches near EOF
*/
#define SLOP (1 + sizeof(union VALUETYPE))
if (!(buf = malloc (HOWMANY + SLOP))) {
return NULL;
}
if (file_reset (ms) == -1) {
goto done;
}
switch (file_fsmagic (ms, inname, &sb)) {
case -1: goto done; /* error */
case 0: break; /* nothing found */
default: rv = 0; goto done; /* matched it and printed type */
}
if (!inname) {
if (fstat (fd, &sb) == 0 && S_ISFIFO (sb.st_mode)) {
ispipe = 1;
}
} else {
int flags = O_RDONLY|O_BINARY;
if (stat (inname, &sb) == 0 && S_ISFIFO (sb.st_mode)) {
#if O_NONBLOCK
flags |= O_NONBLOCK;
#endif
ispipe = 1;
}
errno = 0;
if ((fd = open (inname, flags)) < 0) {
eprintf ("couldn't open file\n");
if (info_from_stat (ms, sb.st_mode) == -1) {
goto done;
}
rv = 0;
goto done;
}
#ifdef O_NONBLOCK
if ((flags = fcntl (fd, F_GETFL)) != -1) {
flags &= ~O_NONBLOCK;
(void)fcntl (fd, F_SETFL, flags);
}
#endif
}
/*
* try looking at the first HOWMANY bytes
*/
#ifdef O_NONBLOCK
if (ispipe) {
ssize_t r = 0;
//while ((r = sread(fd, (void *)&buf[nbytes],
while ((r = read(fd, (void *)&buf[nbytes],
(size_t)(HOWMANY - nbytes))) > 0) {
nbytes += r;
if (r < PIPE_BUF) {
break;
}
}
if (nbytes == 0) {
/* We can not read it, but we were able to stat it. */
if (info_from_stat (ms, sb.st_mode) == -1) {
goto done;
}
rv = 0;
goto done;
}
} else {
#endif
if ((nbytes = read(fd, (char *)buf, HOWMANY)) == -1) {
file_error(ms, errno, "cannot read `%s'", inname);
goto done;
}
#ifdef O_NONBLOCK
}
#endif
(void)memset (buf + nbytes, 0, SLOP); /* NUL terminate */
if (file_buffer (ms, fd, inname, buf, (size_t)nbytes) == -1) {
goto done;
}
rv = 0;
done:
free (buf);
close_and_restore (ms, inname, fd, &sb);
return rv == 0 ? file_getbuffer(ms) : NULL;
}
