Fix "comma after last element" warning.
[dss.git] / fd.c
1 /*
2 * Copyright (C) 2006-2010 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 #include <unistd.h>
8 #include <assert.h>
9 #include <string.h>
10 #include <errno.h>
11 #include <sys/types.h>
12 #include <dirent.h>
13 #include <sys/stat.h>
14 #include <fcntl.h>
15
16
17 #include "gcc-compat.h"
18 #include "error.h"
19 #include "string.h"
20
21 /**
22 * Call a function for each subdirectory of the current working directory.
23 *
24 * \param dirname The directory to traverse.
25 * \param func The function to call for each subdirecrtory.
26 * \param private_data Pointer to an arbitrary data structure.
27 *
28 * For each top-level directory under \a dirname, the supplied function \a func is
29 * called. The full path of the subdirectory and the \a private_data pointer
30 * are passed to \a func.
31 *
32 * \return This function returns immediately if \a func returned a negative
33 * value. In this case \a func must set error_txt and this negative value is
34 * returned to the caller. Otherwise the function returns when all
35 * subdirectories have been passed to \a func.
36 */
37
38 int for_each_subdir(int (*func)(const char *, void *), void *private_data)
39 {
40 struct dirent *entry;
41 int ret;
42 DIR *dir = opendir(".");
43
44 if (!dir)
45 return -ERRNO_TO_DSS_ERROR(errno);
46 while ((entry = readdir(dir))) {
47 mode_t m;
48 struct stat s;
49
50 if (!strcmp(entry->d_name, "."))
51 continue;
52 if (!strcmp(entry->d_name, ".."))
53 continue;
54 ret = lstat(entry->d_name, &s) == -1;
55 if (ret == -1) {
56 ret = -ERRNO_TO_DSS_ERROR(errno);
57 goto out;
58 }
59 m = s.st_mode;
60 if (!S_ISDIR(m))
61 continue;
62 ret = func(entry->d_name, private_data);
63 if (ret < 0)
64 goto out;
65 }
66 ret = 1;
67 out:
68 closedir(dir);
69 return ret;
70 }
71 /**
72 * Wrapper for chdir(2).
73 *
74 * \param path The specified directory.
75 *
76 * \return Standard.
77 */
78 int dss_chdir(const char *path)
79 {
80 if (chdir(path) >= 0)
81 return 1;
82 return -ERRNO_TO_DSS_ERROR(errno);
83 }
84
85 /**
86 * Set a file descriptor to non-blocking mode.
87 *
88 * \param fd The file descriptor.
89 *
90 * \return Standard.
91 */
92 __must_check int mark_fd_nonblocking(int fd)
93 {
94 int flags = fcntl(fd, F_GETFL);
95 if (flags < 0)
96 return -ERRNO_TO_DSS_ERROR(errno);
97 flags = fcntl(fd, F_SETFL, ((long)flags) | O_NONBLOCK);
98 if (flags < 0)
99 return -ERRNO_TO_DSS_ERROR(errno);
100 return 1;
101 }
102
103 /**
104 * dss' wrapper for select(2).
105 *
106 * It calls select(2) (with no exceptfds) and starts over if select() was
107 * interrupted by a signal.
108 *
109 * \param n The highest-numbered descriptor in any of the two sets, plus 1.
110 * \param readfds fds that should be checked for readability.
111 * \param writefds fds that should be checked for writablility.
112 * \param timeout_tv upper bound on the amount of time elapsed before select()
113 * returns.
114 *
115 * \return The return value of the underlying select() call on success, the
116 * negative system error code on errors.
117 *
118 * All arguments are passed verbatim to select(2).
119 * \sa select(2) select_tut(2).
120 */
121 int dss_select(int n, fd_set *readfds, fd_set *writefds,
122 struct timeval *timeout_tv)
123 {
124 int ret, err;
125 do {
126 ret = select(n, readfds, writefds, NULL, timeout_tv);
127 err = errno;
128 } while (ret < 0 && err == EINTR);
129 if (ret < 0)
130 return -ERRNO_TO_DSS_ERROR(errno);
131 return ret;
132 }