1 #include "stdio_impl.h"
2 #include <errno.h>
3 #include <fcntl.h>
4 #include <stdlib.h>
5 #include <string.h>
6 #include <sys/ioctl.h>
7 #include <unistd.h>
8
__fdopen(int fd,const char * mode)9 FILE* __fdopen(int fd, const char* mode) {
10 FILE* f;
11
12 /* Check for valid initial mode character */
13 if (!strchr("rwa", *mode)) {
14 errno = EINVAL;
15 return 0;
16 }
17
18 /* Validate fd */
19 int flags = fcntl(fd, F_GETFL);
20 if (flags < 0) {
21 return 0;
22 }
23
24 /* Allocate FILE+buffer or fail */
25 if (!(f = malloc(sizeof *f + UNGET + BUFSIZ)))
26 return 0;
27
28 /* Zero-fill only the struct, not the buffer */
29 memset(f, 0, sizeof *f);
30
31 /* Impose mode restrictions */
32 if (!strchr(mode, '+'))
33 f->flags = (*mode == 'r') ? F_NOWR : F_NORD;
34
35 /* Apply close-on-exec flag */
36 if (strchr(mode, 'e'))
37 fcntl(fd, F_SETFD, FD_CLOEXEC);
38
39 /* Set append mode on fd if opened for append */
40 if (*mode == 'a') {
41 if (!(flags & O_APPEND))
42 fcntl(fd, F_SETFL, flags | O_APPEND);
43 f->flags |= F_APP;
44 }
45
46 f->fd = fd;
47 f->buf = (unsigned char*)f + sizeof *f + UNGET;
48 f->buf_size = BUFSIZ;
49
50 /* Activate line buffered mode for terminals */
51 f->lbf = EOF;
52 if (!(f->flags & F_NOWR) && isatty(fd))
53 f->lbf = '\n';
54
55 /* Initialize op ptrs. No problem if some are unneeded. */
56 f->read = __stdio_read;
57 f->write = __stdio_write;
58 f->seek = __stdio_seek;
59 f->close = __stdio_close;
60
61 /* Add new FILE to open file list */
62 return __ofl_add(f);
63 }
64
65 weak_alias(__fdopen, fdopen);
66