blob: b9d65babfc10f94fa5ff97dc8015d5560eddee85 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
/* portability.c - code to workaround the deficiencies of various platforms.
*
* Copyright 2012 Rob Landley <rob@landley.net>
* Copyright 2012 Georgi Chorbadzhiyski <gf@unixsol.org>
*/
#include "toys.h"
// We can't fork() on nommu systems, and vfork() requires an exec() or exit()
// before resuming the parent (because they share a heap until then). And no,
// we can't implement our own clone() call that does the equivalent of fork()
// because nommu heaps use physical addresses so if we copy the heap all our
// pointers are wrong. (You need an mmu in order to map two heaps to the same
// address range without interfering with each other.) In the absence of
// a portable way to tell malloc() to start a new heap without freeing the old
// one, you pretty much need the exec().)
// So we exec ourselves (via /proc/self/exe, if anybody knows a way to
// re-exec self without depending on the filesystem, I'm all ears),
// and use the arguments to signal reentry.
#if CFG_TOYBOX_FORK
pid_t xfork(void)
{
pid_t pid = fork();
if (pid < 0) perror_exit("fork");
return pid;
}
#endif
void xgetrandom(void *buf, unsigned buflen, unsigned flags)
{
int fd;
#if CFG_TOYBOX_GETRANDOM
if (buflen == getrandom(buf, buflen, flags)) return;
if (!CFG_TOYBOX_ON_ANDROID || errno!=ENOSYS) perror_exit("getrandom");
#endif
fd = xopen(flags ? "/dev/random" : "/dev/urandom", O_RDONLY);
xreadall(fd, buf, buflen);
close(fd);
}
#if defined(__APPLE__)
extern char **environ;
int clearenv(void)
{
*environ = NULL;
return 0;
}
#endif
|
