run: Don't kill children twice.
[dss.git] / file.c
1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #include <stdio.h>
4 #include <unistd.h>
5 #include <assert.h>
6 #include <string.h>
7 #include <errno.h>
8 #include <sys/types.h>
9 #include <dirent.h>
10 #include <sys/stat.h>
11 #include <fcntl.h>
12
13 #include "gcc-compat.h"
14 #include "err.h"
15 #include "str.h"
16 #include "file.h"
17
18 /**
19 * Call a function for each subdirectory of the current working directory.
20 *
21 * \param dirname The directory to traverse.
22 * \param func The function to call for each subdirectory.
23 * \param private_data Pointer to an arbitrary data structure.
24 *
25 * For each top-level directory under \a dirname, the supplied function \a func is
26 * called. The full path of the subdirectory and the \a private_data pointer
27 * are passed to \a func.
28 *
29 * \return This function returns immediately if \a func returned a negative
30 * value. In this case \a func must set error_txt and this negative value is
31 * returned to the caller. Otherwise the function returns when all
32 * subdirectories have been passed to \a func.
33 */
34
35 int for_each_subdir(int (*func)(const char *, void *), void *private_data)
36 {
37 struct dirent *entry;
38 int ret;
39 DIR *dir = opendir(".");
40
41 if (!dir)
42 return -ERRNO_TO_DSS_ERROR(errno);
43 while ((entry = readdir(dir))) {
44 mode_t m;
45 struct stat s;
46
47 if (!strcmp(entry->d_name, "."))
48 continue;
49 if (!strcmp(entry->d_name, ".."))
50 continue;
51 ret = lstat(entry->d_name, &s) == -1;
52 if (ret == -1) {
53 ret = -ERRNO_TO_DSS_ERROR(errno);
54 goto out;
55 }
56 m = s.st_mode;
57 if (!S_ISDIR(m))
58 continue;
59 ret = func(entry->d_name, private_data);
60 if (ret < 0)
61 goto out;
62 }
63 ret = 1;
64 out:
65 closedir(dir);
66 return ret;
67 }
68
69 /**
70 * Set a file descriptor to non-blocking mode.
71 *
72 * \param fd The file descriptor.
73 *
74 * \return Standard.
75 */
76 __must_check int mark_fd_nonblocking(int fd)
77 {
78 int flags = fcntl(fd, F_GETFL);
79 if (flags < 0)
80 return -ERRNO_TO_DSS_ERROR(errno);
81 flags = fcntl(fd, F_SETFL, ((long)flags) | O_NONBLOCK);
82 if (flags < 0)
83 return -ERRNO_TO_DSS_ERROR(errno);
84 return 1;
85 }
86
87 /**
88 * dss' wrapper for select(2).
89 *
90 * It calls select(2) (with no exceptfds) and starts over if select() was
91 * interrupted by a signal.
92 *
93 * \param n The highest-numbered descriptor in any of the two sets, plus 1.
94 * \param readfds fds that should be checked for readability.
95 * \param writefds fds that should be checked for writablility.
96 * \param timeout_tv upper bound on the amount of time elapsed before select()
97 * returns.
98 *
99 * \return The return value of the underlying select() call on success, the
100 * negative system error code on errors.
101 *
102 * All arguments are passed verbatim to select(2).
103 * \sa select(2) select_tut(2).
104 */
105 int dss_select(int n, fd_set *readfds, fd_set *writefds,
106 struct timeval *timeout_tv)
107 {
108 int ret, err;
109 do {
110 ret = select(n, readfds, writefds, NULL, timeout_tv);
111 err = errno;
112 } while (ret < 0 && err == EINTR);
113 if (ret < 0)
114 return -ERRNO_TO_DSS_ERROR(errno);
115 return ret;
116 }