30623d1b321b8dfed84b07c33034fc20e05dd351
2 * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
19 /** \file fd.c helper functions for file descriptor handling */
24 #include <sys/select.h>
28 * check whether a file exists
30 * \param fn the file name
32 * \return Non-zero iff file exists.
34 int file_exists(const char *fn
)
38 return !stat(fn
, &statbuf
);
42 * paraslash's wrapper for select(2)
44 * It calls select(2) (with no exceptfds) and starts over if select() was
45 * interrupted by a signal.
47 * \param n the highest-numbered descriptor in any of the two sets, plus 1
48 * \param readfds fds that should be checked for readability
49 * \param writefds fds that should be checked for writablility
50 * \param timeout_tv upper bound on the amount of time elapsed before select()
53 * \return The return value of the underlying select() call.
55 * All arguments are passed verbatim to select(2).
56 * \sa select(2) select_tut(2)
58 int para_select(int n
, fd_set
*readfds
, fd_set
*writefds
,
59 struct timeval
*timeout_tv
)
63 ret
= select(n
, readfds
, writefds
, NULL
, timeout_tv
);
65 } while (ret
< 0 && err
== EINTR
);
67 PARA_CRIT_LOG("select error: %s, max_fileno: %d\n",
73 * set a file descriptor to non-blocking mode
75 * \param fd The file descriptor
77 * \returns 1 on success, -E_F_GETFL, -E_F_SETFL, on errors.
79 int mark_fd_nonblock(int fd
)
81 int flags
= fcntl(fd
, F_GETFL
);
84 if (fcntl(fd
, F_SETFL
, ((long)flags
) | O_NONBLOCK
) < 0)
90 * set a file descriptor in a fd_set
92 * \param fd the file descriptor to be set
93 * \param fds the file descriptor set
94 * \param max_fileno highest-numbered file descriptor
96 * This wrapper for FD_SET() passes its first two arguments to \p FD_SET. Upon
97 * return, \a max_fileno contains the maximum of the old_value and \a fd.
101 void para_fd_set(int fd
, fd_set
*fds
, int *max_fileno
)
104 if (fd
< 0 || fd
>= FD_SETSIZE
) {
105 PARA_EMERG_LOG("fatal: tried to add invalid fd %d\n", fd
);
110 int flags
= fcntl(fd
, F_GETFL
);
111 if (!(flags
& O_NONBLOCK
)) {
112 PARA_EMERG_LOG("fd %d is a blocking file descriptor\n", fd
);
118 *max_fileno
= PARA_MAX(*max_fileno
, fd
);
122 * paraslash's wrapper for fread(3)
124 * \param dest destination pointer
125 * \param nbytes size of one element
126 * \param nmemb number of elements to write
127 * \param stream the input stream
129 * \return negative on errors, zero on end of file, and the number of bytes
130 * (not elements) read on success.
134 __must_check
int para_fread(void *dest
, size_t nbytes
, size_t nmemb
, FILE *stream
)
136 size_t res
= fread(dest
, nbytes
, nmemb
, stream
);
138 return nbytes
* nmemb
;
144 * paraslash's wrapper for fgets(3)
145 * \param line pointer to the buffer to store the line
146 * \param size the size of the buffer given by \a line
147 * \param f the stream to read from
149 * \return Unlike the standard fgets() function, an integer value
150 * is returned. On success, this function returns 1. On errors, -E_FGETS
151 * is returned. A zero return value indicates an end of file condition.
153 __must_check
int para_fgets(char *line
, int size
, FILE *f
)
156 if (fgets(line
, size
, f
))
162 if (errno
!= EINTR
) {
163 PARA_ERROR_LOG("%s\n", strerror(errno
));
171 * paralash's wrapper for fseek(3)
173 * \param stream stream to seek
174 * \param offset added to the position specified by whence
175 * \param whence \p SEEK_SET, \p SEEK_CUR, or \p SEEK_END
177 * \return positive on success, -E_FSEEK on errors.
181 int para_fseek(FILE *stream
, long offset
, int whence
)
183 int ret
= fseek(stream
, offset
, whence
);
184 return ret
< 0? -E_FSEEK
: 1;
188 * *paraslash's wrapper for mmap
190 * \param length number of bytes to mmap
191 * \param prot either PROT_NONE or the bitwise OR of one or more of
192 * PROT_EXEC PROT_READ PROT_WRITE
193 * \param flags exactly one of MAP_SHARED and MAP_PRIVATE
194 * \param fd the file to mmap from
195 * \param offset mmap start
197 * \return This function either returns a valid pointer to the mapped area
198 * or calls exit() on errors.
200 void *para_mmap(size_t length
, int prot
, int flags
, int fd
, off_t offset
)
202 void *ret
= mmap(NULL
, length
, prot
, flags
, fd
, offset
);
203 if (ret
!= MAP_FAILED
)
205 PARA_EMERG_LOG("mmap failed: %s", strerror(errno
));