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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
36static 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
44struct 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
52struct io_dir {
53 int dirfd;
54 ssize_t available_bytes;
55 struct io_dirent64 *next;
56 struct io_dirent64 buff[4];
57};
58
59static inline void io_dir__init(struct io_dir *iod, int dirfd)
60{
61 iod->dirfd = dirfd;
62 iod->available_bytes = 0;
63}
64
65static inline void io_dir__rewinddir(struct io_dir *iod)
66{
67 lseek(iod->dirfd, 0, SEEK_SET);
68 iod->available_bytes = 0;
69}
70
71static 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
89static 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__ */