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/****************************************************************************
* bfs *
* Copyright (C) 2021 Tavian Barnes <tavianator@tavianator.com> *
* *
* Permission to use, copy, modify, and/or distribute this software for any *
* purpose with or without fee is hereby granted. *
* *
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF *
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR *
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES *
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN *
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF *
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
****************************************************************************/
#include "dir.h"
#include "util.h"
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#if __linux__
# include <sys/syscall.h>
#endif // __linux__
enum bfs_type bfs_mode_to_type(mode_t mode) {
switch (mode & S_IFMT) {
#ifdef S_IFBLK
case S_IFBLK:
return BFS_BLK;
#endif
#ifdef S_IFCHR
case S_IFCHR:
return BFS_CHR;
#endif
#ifdef S_IFDIR
case S_IFDIR:
return BFS_DIR;
#endif
#ifdef S_IFDOOR
case S_IFDOOR:
return BFS_DOOR;
#endif
#ifdef S_IFIFO
case S_IFIFO:
return BFS_FIFO;
#endif
#ifdef S_IFLNK
case S_IFLNK:
return BFS_LNK;
#endif
#ifdef S_IFPORT
case S_IFPORT:
return BFS_PORT;
#endif
#ifdef S_IFREG
case S_IFREG:
return BFS_REG;
#endif
#ifdef S_IFSOCK
case S_IFSOCK:
return BFS_SOCK;
#endif
#ifdef S_IFWHT
case S_IFWHT:
return BFS_WHT;
#endif
default:
return BFS_UNKNOWN;
}
}
#if __linux__
/**
* This is not defined in the kernel headers for some reason, callers have to
* define it themselves.
*/
struct linux_dirent64 {
ino64_t d_ino;
off64_t d_off;
unsigned short d_reclen;
unsigned char d_type;
char d_name[];
};
// Make the whole allocation 64k
#define BUF_SIZE ((64 << 10) - 8)
#endif
struct bfs_dir {
#if __linux__
int fd;
unsigned short pos;
unsigned short size;
#else
DIR *dir;
struct dirent *de;
#endif
};
struct bfs_dir *bfs_opendir(int at_fd, const char *at_path) {
#if __linux__
struct bfs_dir *dir = malloc(sizeof(*dir) + BUF_SIZE);
#else
struct bfs_dir *dir = malloc(sizeof(*dir));
#endif
if (!dir) {
return NULL;
}
int fd;
if (at_path) {
fd = openat(at_fd, at_path, O_RDONLY | O_CLOEXEC | O_DIRECTORY);
} else if (at_fd >= 0) {
fd = at_fd;
} else {
free(dir);
errno = EBADF;
return NULL;
}
if (fd < 0) {
free(dir);
return NULL;
}
#if __linux__
dir->fd = fd;
dir->pos = 0;
dir->size = 0;
#else
dir->dir = fdopendir(fd);
if (!dir->dir) {
int error = errno;
close(fd);
free(dir);
errno = error;
return NULL;
}
dir->de = NULL;
#endif // __linux__
return dir;
}
int bfs_dirfd(const struct bfs_dir *dir) {
#if __linux__
return dir->fd;
#else
return dirfd(dir->dir);
#endif
}
/** Convert a dirent type to a bfs_type. */
static enum bfs_type translate_type(int d_type) {
switch (d_type) {
#ifdef DT_BLK
case DT_BLK:
return BFS_BLK;
#endif
#ifdef DT_CHR
case DT_CHR:
return BFS_CHR;
#endif
#ifdef DT_DIR
case DT_DIR:
return BFS_DIR;
#endif
#ifdef DT_DOOR
case DT_DOOR:
return BFS_DOOR;
#endif
#ifdef DT_FIFO
case DT_FIFO:
return BFS_FIFO;
#endif
#ifdef DT_LNK
case DT_LNK:
return BFS_LNK;
#endif
#ifdef DT_PORT
case DT_PORT:
return BFS_PORT;
#endif
#ifdef DT_REG
case DT_REG:
return BFS_REG;
#endif
#ifdef DT_SOCK
case DT_SOCK:
return BFS_SOCK;
#endif
#ifdef DT_WHT
case DT_WHT:
return BFS_WHT;
#endif
}
return BFS_UNKNOWN;
}
#if !__linux__
/** Get the type from a struct dirent if it exists, and convert it. */
static enum bfs_type dirent_type(const struct dirent *de) {
#if defined(_DIRENT_HAVE_D_TYPE) || defined(DT_UNKNOWN)
return translate_type(de->d_type);
#else
return BFS_UNKNOWN;
#endif
}
#endif
/** Check if a name is . or .. */
static bool is_dot(const char *name) {
return name[0] == '.' && (name[1] == '\0' || (name[1] == '.' && name[2] == '\0'));
}
int bfs_readdir(struct bfs_dir *dir, struct bfs_dirent *de) {
while (true) {
#if __linux__
char *buf = (char *)(dir + 1);
if (dir->pos >= dir->size) {
// Make sure msan knows the buffer is initialized
#if BFS_HAS_FEATURE(memory_sanitizer, false)
memset(buf, 0, BUF_SIZE);
#endif
ssize_t size = syscall(__NR_getdents64, dir->fd, buf, BUF_SIZE);
if (size <= 0) {
return size;
}
dir->pos = 0;
dir->size = size;
}
const struct linux_dirent64 *lde = (void *)(buf + dir->pos);
dir->pos += lde->d_reclen;
if (is_dot(lde->d_name)) {
continue;
}
if (de) {
de->type = translate_type(lde->d_type);
de->name = lde->d_name;
}
return 1;
#else // !__linux__
errno = 0;
dir->de = readdir(dir->dir);
if (dir->de) {
if (is_dot(dir->de->d_name)) {
continue;
}
if (de) {
de->type = dirent_type(dir->de);
de->name = dir->de->d_name;
}
return 1;
} else if (errno != 0) {
return -1;
} else {
return 0;
}
#endif // !__linux__
}
}
int bfs_closedir(struct bfs_dir *dir) {
#if __linux__
int ret = close(dir->fd);
#else
int ret = closedir(dir->dir);
#endif
free(dir);
return ret;
}
int bfs_freedir(struct bfs_dir *dir) {
#if __linux__
int ret = dir->fd;
free(dir);
return ret;
#elif __FreeBSD__
int ret = fdclosedir(dir->dir);
free(dir);
return ret;
#else
int ret = dup_cloexec(dirfd(dir->dir));
bfs_closedir(dir);
return ret;
#endif
}
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