File: pipe2.c

package info (click to toggle)
sharutils 1:4.15.2-4
  • links: PTS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 10,936 kB
  • sloc: ansic: 53,545; sh: 6,933; makefile: 726; yacc: 291; sed: 16
file content (168 lines) | stat: -rw-r--r-- 4,321 bytes parent folder | download | duplicates (6)
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
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/* Create a pipe, with specific opening flags.
   Copyright (C) 2009-2015 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with this program; if not, see <http://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include <unistd.h>

#include <errno.h>
#include <fcntl.h>

#include "binary-io.h"
#include "verify.h"

#if GNULIB_defined_O_NONBLOCK
# include "nonblocking.h"
#endif

#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Native Windows API.  */

# include <io.h>

#endif

int
pipe2 (int fd[2], int flags)
{
  /* Mingw _pipe() corrupts fd on failure; also, if we succeed at
     creating the pipe but later fail at changing fcntl, we want
     to leave fd unchanged: http://austingroupbugs.net/view.php?id=467  */
  int tmp[2];
  tmp[0] = fd[0];
  tmp[1] = fd[1];

#if HAVE_PIPE2
# undef pipe2
  /* Try the system call first, if it exists.  (We may be running with a glibc
     that has the function but with an older kernel that lacks it.)  */
  {
    /* Cache the information whether the system call really exists.  */
    static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
    if (have_pipe2_really >= 0)
      {
        int result = pipe2 (fd, flags);
        if (!(result < 0 && errno == ENOSYS))
          {
            have_pipe2_really = 1;
            return result;
          }
        have_pipe2_really = -1;
      }
  }
#endif

  /* Check the supported flags.  */
  if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_BINARY | O_TEXT)) != 0)
    {
      errno = EINVAL;
      return -1;
    }

#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Native Windows API.  */

  if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0)
    {
      fd[0] = tmp[0];
      fd[1] = tmp[1];
      return -1;
    }

  /* O_NONBLOCK handling.
     On native Windows platforms, O_NONBLOCK is defined by gnulib.  Use the
     functions defined by the gnulib module 'nonblocking'.  */
# if GNULIB_defined_O_NONBLOCK
  if (flags & O_NONBLOCK)
    {
      if (set_nonblocking_flag (fd[0], true) != 0
          || set_nonblocking_flag (fd[1], true) != 0)
        goto fail;
    }
# else
  {
    verify (O_NONBLOCK == 0);
  }
# endif

  return 0;

#else
/* Unix API.  */

  if (pipe (fd) < 0)
    return -1;

  /* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/pipe.html>
     says that initially, the O_NONBLOCK and FD_CLOEXEC flags are cleared on
     both fd[0] and fd[1].  */

  /* O_NONBLOCK handling.
     On Unix platforms, O_NONBLOCK is defined by the system.  Use fcntl().  */
  if (flags & O_NONBLOCK)
    {
      int fcntl_flags;

      if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0
          || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
          || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
          || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
        goto fail;
    }

  if (flags & O_CLOEXEC)
    {
      int fcntl_flags;

      if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0
          || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
          || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
          || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
        goto fail;
    }

# if O_BINARY
  if (flags & O_BINARY)
    {
      set_binary_mode (fd[1], O_BINARY);
      set_binary_mode (fd[0], O_BINARY);
    }
  else if (flags & O_TEXT)
    {
      set_binary_mode (fd[1], O_TEXT);
      set_binary_mode (fd[0], O_TEXT);
    }
# endif

  return 0;

#endif

#if GNULIB_defined_O_NONBLOCK || \
  !((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__)
 fail:
  {
    int saved_errno = errno;
    close (fd[0]);
    close (fd[1]);
    fd[0] = tmp[0];
    fd[1] = tmp[1];
    errno = saved_errno;
    return -1;
  }
#endif
}