1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 /*
3 * Lightweight directory reading library.
4 */
5 #ifndef __API_IO_DIR__
6 #define __API_IO_DIR__
7
8 #include <dirent.h>
9 #include <fcntl.h>
10 #include <stdlib.h>
11 #include <unistd.h>
12 #include <sys/stat.h>
13 #include <sys/syscall.h>
14 #include <linux/limits.h>
15
16 #if !defined(SYS_getdents64)
17 #if defined(__x86_64__) || defined(__arm__)
18 #define SYS_getdents64 217
19 #elif defined(__i386__) || defined(__s390x__) || defined(__sh__)
20 #define SYS_getdents64 220
21 #elif defined(__alpha__)
22 #define SYS_getdents64 377
23 #elif defined(__mips__)
24 #define SYS_getdents64 308
25 #elif defined(__powerpc64__) || defined(__powerpc__)
26 #define SYS_getdents64 202
27 #elif defined(__sparc64__) || defined(__sparc__)
28 #define SYS_getdents64 154
29 #elif defined(__xtensa__)
30 #define SYS_getdents64 60
31 #else
32 #define SYS_getdents64 61
33 #endif
34 #endif /* !defined(SYS_getdents64) */
35
perf_getdents64(int fd,void * dirp,size_t count)36 static inline ssize_t perf_getdents64(int fd, void *dirp, size_t count)
37 {
38 #ifdef MEMORY_SANITIZER
39 memset(dirp, 0, count);
40 #endif
41 return syscall(SYS_getdents64, fd, dirp, count);
42 }
43
44 struct io_dirent64 {
45 ino64_t d_ino; /* 64-bit inode number */
46 off64_t d_off; /* 64-bit offset to next structure */
47 unsigned short d_reclen; /* Size of this dirent */
48 unsigned char d_type; /* File type */
49 char d_name[NAME_MAX + 1]; /* Filename (null-terminated) */
50 };
51
52 struct io_dir {
53 int dirfd;
54 ssize_t available_bytes;
55 struct io_dirent64 *next;
56 struct io_dirent64 buff[4];
57 };
58
io_dir__init(struct io_dir * iod,int dirfd)59 static inline void io_dir__init(struct io_dir *iod, int dirfd)
60 {
61 iod->dirfd = dirfd;
62 iod->available_bytes = 0;
63 }
64
io_dir__rewinddir(struct io_dir * iod)65 static inline void io_dir__rewinddir(struct io_dir *iod)
66 {
67 lseek(iod->dirfd, 0, SEEK_SET);
68 iod->available_bytes = 0;
69 }
70
io_dir__readdir(struct io_dir * iod)71 static inline struct io_dirent64 *io_dir__readdir(struct io_dir *iod)
72 {
73 struct io_dirent64 *entry;
74
75 if (iod->available_bytes <= 0) {
76 ssize_t rc = perf_getdents64(iod->dirfd, iod->buff, sizeof(iod->buff));
77
78 if (rc <= 0)
79 return NULL;
80 iod->available_bytes = rc;
81 iod->next = iod->buff;
82 }
83 entry = iod->next;
84 iod->next = (struct io_dirent64 *)((char *)entry + entry->d_reclen);
85 iod->available_bytes -= entry->d_reclen;
86 return entry;
87 }
88
io_dir__is_dir(const struct io_dir * iod,struct io_dirent64 * dent)89 static inline bool io_dir__is_dir(const struct io_dir *iod, struct io_dirent64 *dent)
90 {
91 if (dent->d_type == DT_UNKNOWN) {
92 struct stat st;
93
94 if (fstatat(iod->dirfd, dent->d_name, &st, /*flags=*/0))
95 return false;
96
97 if (S_ISDIR(st.st_mode)) {
98 dent->d_type = DT_DIR;
99 return true;
100 }
101 }
102 return dent->d_type == DT_DIR;
103 }
104
105 #endif /* __API_IO_DIR__ */
106