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320054e8 DG |
1 | // Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/ |
2 | // | |
3 | // SPDX-License-Identifier: BSD-2-Clause | |
4 | ||
446cb3f1 | 5 | #include <wasi/api.h> |
a94d2d04 | 6 | #include <wasi/libc.h> |
320054e8 DG |
7 | #include <dirent.h> |
8 | #include <errno.h> | |
9 | #include <fcntl.h> | |
10 | #include <stdlib.h> | |
11 | #include <string.h> | |
12 | #include <unistd.h> | |
13 | ||
14 | #include "dirent_impl.h" | |
15 | ||
16 | static int sel_true(const struct dirent *de) { | |
17 | return 1; | |
18 | } | |
19 | ||
20 | int scandirat(int dirfd, const char *dir, struct dirent ***namelist, | |
21 | int (*sel)(const struct dirent *), | |
22 | int (*compar)(const struct dirent **, const struct dirent **)) { | |
23 | // Match all files if no select function is provided. | |
24 | if (sel == NULL) | |
25 | sel = sel_true; | |
26 | ||
27 | // Open the directory. | |
a94d2d04 | 28 | int fd = __wasilibc_openat_nomode(dirfd, dir, O_RDONLY | O_NONBLOCK | O_DIRECTORY); |
320054e8 DG |
29 | if (fd == -1) |
30 | return -1; | |
31 | ||
32 | // Allocate a read buffer for the directory entries. | |
33 | size_t buffer_size = DIRENT_DEFAULT_BUFFER_SIZE; | |
34 | char *buffer = malloc(buffer_size); | |
35 | if (buffer == NULL) { | |
36 | close(fd); | |
37 | return -1; | |
38 | } | |
39 | size_t buffer_processed = buffer_size; | |
40 | size_t buffer_used = buffer_size; | |
41 | ||
42 | // Space for the array to return to the caller. | |
43 | struct dirent **dirents = NULL; | |
44 | size_t dirents_size = 0; | |
45 | size_t dirents_used = 0; | |
46 | ||
47 | __wasi_dircookie_t cookie = __WASI_DIRCOOKIE_START; | |
48 | for (;;) { | |
49 | // Extract the next dirent header. | |
50 | size_t buffer_left = buffer_used - buffer_processed; | |
51 | if (buffer_left < sizeof(__wasi_dirent_t)) { | |
52 | // End-of-file. | |
53 | if (buffer_used < buffer_size) | |
54 | break; | |
55 | goto read_entries; | |
56 | } | |
57 | __wasi_dirent_t entry; | |
58 | memcpy(&entry, buffer + buffer_processed, sizeof(entry)); | |
59 | ||
60 | size_t entry_size = sizeof(__wasi_dirent_t) + entry.d_namlen; | |
61 | if (entry.d_namlen == 0) { | |
62 | // Invalid pathname length. Skip the entry. | |
63 | buffer_processed += entry_size; | |
64 | continue; | |
65 | } | |
66 | ||
67 | // The entire entry must be present in buffer space. If not, read | |
68 | // the entry another time. Ensure that the read buffer is large | |
69 | // enough to fit at least this single entry. | |
70 | if (buffer_left < entry_size) { | |
71 | while (buffer_size < entry_size) | |
72 | buffer_size *= 2; | |
73 | char *new_buffer = realloc(buffer, buffer_size); | |
74 | if (new_buffer == NULL) | |
75 | goto bad; | |
76 | buffer = new_buffer; | |
77 | goto read_entries; | |
78 | } | |
79 | ||
80 | // Skip entries having null bytes in the filename. | |
81 | const char *name = buffer + buffer_processed + sizeof(entry); | |
82 | buffer_processed += entry_size; | |
83 | if (memchr(name, '\0', entry.d_namlen) != NULL) | |
84 | continue; | |
85 | ||
86 | // Create the new directory entry. | |
87 | struct dirent *dirent = | |
88 | malloc(offsetof(struct dirent, d_name) + entry.d_namlen + 1); | |
89 | if (dirent == NULL) | |
90 | goto bad; | |
91 | dirent->d_ino = entry.d_ino; | |
92 | dirent->d_type = entry.d_type; | |
93 | memcpy(dirent->d_name, name, entry.d_namlen); | |
94 | dirent->d_name[entry.d_namlen] = '\0'; | |
95 | cookie = entry.d_next; | |
96 | ||
97 | if (sel(dirent)) { | |
98 | // Add the entry to the results. | |
99 | if (dirents_used == dirents_size) { | |
100 | dirents_size = dirents_size < 8 ? 8 : dirents_size * 2; | |
101 | struct dirent **new_dirents = | |
102 | realloc(dirents, dirents_size * sizeof(*dirents)); | |
103 | if (new_dirents == NULL) { | |
104 | free(dirent); | |
105 | goto bad; | |
106 | } | |
107 | dirents = new_dirents; | |
108 | } | |
109 | dirents[dirents_used++] = dirent; | |
110 | } else { | |
111 | // Discard the entry. | |
112 | free(dirent); | |
113 | } | |
114 | continue; | |
115 | ||
116 | read_entries:; | |
117 | // Load more directory entries and continue. | |
446cb3f1 DG |
118 | // TODO: Remove the cast on `buffer` once the witx is updated with char8 support. |
119 | __wasi_errno_t error = __wasi_fd_readdir(fd, (uint8_t *)buffer, buffer_size, | |
320054e8 DG |
120 | cookie, &buffer_used); |
121 | if (error != 0) { | |
122 | errno = error; | |
123 | goto bad; | |
124 | } | |
125 | buffer_processed = 0; | |
126 | } | |
127 | ||
128 | // Sort results and return them. | |
129 | free(buffer); | |
130 | close(fd); | |
131 | (qsort)(dirents, dirents_used, sizeof(*dirents), | |
132 | (int (*)(const void *, const void *))compar); | |
133 | *namelist = dirents; | |
134 | return dirents_used; | |
135 | ||
136 | bad: | |
137 | // Deallocate partially created results. | |
138 | for (size_t i = 0; i < dirents_used; ++i) | |
139 | free(dirents[i]); | |
140 | free(dirents); | |
141 | free(buffer); | |
142 | close(fd); | |
143 | return -1; | |
144 | } |