Ruby 2.7.0p0(2019-12-25revision647ee6f091eafcce70ffb75ddf7e121e192ab217)

dup2.c
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1 /*
2 * Public domain dup2() lookalike
3 * by Curtis Jackson @ AT&T Technologies, Burlington, NC
4 * electronic address: burl!rcj
5 *
6 * dup2 performs the following functions:
7 *
8 * Check to make sure that fd1 is a valid open file descriptor.
9 * Check to see if fd2 is already open; if so, close it.
10 * Duplicate fd1 onto fd2; checking to make sure fd2 is a valid fd.
11 * Return fd2 if all went well; return BADEXIT otherwise.
12 */
13
14 #include "ruby/config.h"
15
16 #if defined(HAVE_FCNTL)
17 # include <fcntl.h>
18 #endif
19
20 #if !defined(HAVE_FCNTL) || !defined(F_DUPFD)
21 # include <errno.h>
22 #endif
23
24 #define BADEXIT -1
25
26 int
27 dup2(int fd1, int fd2)
28 {
29 #if defined(HAVE_FCNTL) && defined(F_DUPFD)
30 if (fd1 != fd2) {
31 #ifdef F_GETFL
32 if (fcntl(fd1, F_GETFL) < 0)
33 return BADEXIT;
34 if (fcntl(fd2, F_GETFL) >= 0)
35 close(fd2);
36 #else
37 close(fd2);
38 #endif
39 if (fcntl(fd1, F_DUPFD, fd2) < 0)
40 return BADEXIT;
41 }
42 return fd2;
43 #else
44 extern int errno;
45 int i, fd, fds[256];
46
47 if (fd1 == fd2) return 0;
48 close(fd2);
49 for (i=0; i<256; i++) {
50 fd = fds[i] = dup(fd1);
51 if (fd == fd2) break;
52 }
53 while (i) {
54 close(fds[i--]);
55 }
56 if (fd == fd2) return 0;
57 errno = EMFILE;
58 return BADEXIT;
59 #endif
60 }
BADEXIT
#define BADEXIT
Definition: dup2.c:24
close
int close(int __fildes)
F_DUPFD
#define F_DUPFD
Definition: win32.h:602
fcntl
int fcntl(int, int,...)
Definition: win32.c:4282
i
uint32_t i
Definition: rb_mjit_min_header-2.7.0.h:5464
dup2
int dup2(int fd1, int fd2)
Definition: dup2.c:27
errno
int errno
dup
int dup(int __fildes)
EMFILE
#define EMFILE
Definition: rb_mjit_min_header-2.7.0.h:10961