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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/tools/lib/api/io_dir.h
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/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */

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/*

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 * Lightweight directory reading library.

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 */

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#ifndef __API_IO_DIR__

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#define __API_IO_DIR__

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#include <dirent.h>

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#include <fcntl.h>

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#include <stdlib.h>

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#include <unistd.h>

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#include <sys/stat.h>

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#include <sys/syscall.h>

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#include <linux/limits.h>

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#if !defined(SYS_getdents64)

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#if defined(__x86_64__) || defined(__arm__)

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  #define SYS_getdents64 217

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#elif defined(__i386__) || defined(__s390x__) || defined(__sh__)

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  #define SYS_getdents64 220

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#elif defined(__alpha__)

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  #define SYS_getdents64 377

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#elif defined(__mips__)

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  #define SYS_getdents64 308

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#elif defined(__powerpc64__) || defined(__powerpc__)

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  #define SYS_getdents64 202

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#elif defined(__sparc64__) || defined(__sparc__)

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  #define SYS_getdents64 154

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#elif defined(__xtensa__)

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  #define SYS_getdents64 60

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#else

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  #define SYS_getdents64 61

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#endif

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#endif /* !defined(SYS_getdents64) */

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static inline ssize_t perf_getdents64(int fd, void *dirp, size_t count)

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{

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#ifdef MEMORY_SANITIZER

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	memset(dirp, 0, count);

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#endif

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	return syscall(SYS_getdents64, fd, dirp, count);

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}

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struct io_dirent64 {

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	ino64_t        d_ino;    /* 64-bit inode number */

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	off64_t        d_off;    /* 64-bit offset to next structure */

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	unsigned short d_reclen; /* Size of this dirent */

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	unsigned char  d_type;   /* File type */

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	char           d_name[NAME_MAX + 1]; /* Filename (null-terminated) */

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};

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struct io_dir {

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	int dirfd;

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	ssize_t available_bytes;

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	struct io_dirent64 *next;

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	struct io_dirent64 buff[4];

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};

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static inline void io_dir__init(struct io_dir *iod, int dirfd)

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{

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	iod->dirfd = dirfd;

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	iod->available_bytes = 0;

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}

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static inline void io_dir__rewinddir(struct io_dir *iod)

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{

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	lseek(iod->dirfd, 0, SEEK_SET);

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	iod->available_bytes = 0;

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}

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static inline struct io_dirent64 *io_dir__readdir(struct io_dir *iod)

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{

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	struct io_dirent64 *entry;

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	if (iod->available_bytes <= 0) {

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		ssize_t rc = perf_getdents64(iod->dirfd, iod->buff, sizeof(iod->buff));

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		if (rc <= 0)

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			return NULL;

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		iod->available_bytes = rc;

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		iod->next = iod->buff;

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	}

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	entry = iod->next;

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	iod->next = (struct io_dirent64 *)((char *)entry + entry->d_reclen);

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	iod->available_bytes -= entry->d_reclen;

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	return entry;

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}

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static inline bool io_dir__is_dir(const struct io_dir *iod, struct io_dirent64 *dent)

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{

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	if (dent->d_type == DT_UNKNOWN) {

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		struct stat st;

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		if (fstatat(iod->dirfd, dent->d_name, &st, /*flags=*/0))

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			return false;

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		if (S_ISDIR(st.st_mode)) {

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			dent->d_type = DT_DIR;

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			return true;

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		}

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	}

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	return dent->d_type == DT_DIR;

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}

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#endif  /* __API_IO_DIR__ */

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