cosmopolitan/libc/stdio/dirstream.c
2021-02-08 04:04:42 -08:00

321 lines
9.2 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ 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 "libc/bits/bits.h"
#include "libc/calls/internal.h"
#include "libc/calls/struct/dirent.h"
#include "libc/dce.h"
#include "libc/macros.h"
#include "libc/mem/mem.h"
#include "libc/nt/enum/fileflagandattributes.h"
#include "libc/nt/enum/filetype.h"
#include "libc/nt/files.h"
#include "libc/nt/runtime.h"
#include "libc/nt/struct/win32finddata.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/dt.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
/**
* @fileoverview Directory Streams for Linux+Mac+Windows+FreeBSD+OpenBSD.
*
* System interfaces for listing the contents of file system directories
* are famously incompatible across platforms. Most native projects that
* have been around a long time implement wrappers for this. Normally it
* will only be for DOS or Windows support. So this is the first time it
* has been done for five platforms, having a remarkably tiny footprint.
*/
/**
* Directory stream object.
*/
struct dirstream {
int64_t fd;
int64_t tell;
struct dirent ent;
union {
struct {
unsigned buf_pos;
unsigned buf_end;
char buf[BUFSIZ];
};
struct {
bool isdone;
struct NtWin32FindData windata;
};
};
};
/**
* FreeBSD getdents() and XNU getdirentries() ABI.
*/
struct dirent_bsd {
uint32_t d_fileno;
uint16_t d_reclen;
uint8_t d_type;
uint8_t d_namlen;
char d_name[256];
};
/**
* OpenBSD getdents() ABI.
*/
struct dirent_openbsd {
uint64_t d_fileno;
int64_t d_off;
uint16_t d_reclen;
uint8_t d_type;
uint8_t d_namlen;
uint8_t __zomg[4];
char d_name[256];
};
/**
* NetBSD getdents().
*/
struct dirent_netbsd {
uint64_t d_fileno;
uint16_t d_reclen;
uint16_t d_namlen;
uint8_t d_type;
char d_name[512];
};
static textwindows DIR *opendir_nt_impl(char16_t name[PATH_MAX], size_t len) {
DIR *res;
if (len + 2 + 1 <= PATH_MAX) {
if (name[len - 1] != u'\\') name[len++] = u'\\';
name[len++] = u'*';
name[len] = u'\0';
if ((res = calloc(1, sizeof(DIR)))) {
if ((res->fd = FindFirstFile(name, &res->windata)) != -1) {
return res;
} else {
__winerr();
}
free(res);
}
} else {
enametoolong();
}
return NULL;
}
static textwindows noinline DIR *opendir_nt(const char *path) {
int len;
char16_t name[PATH_MAX];
if ((len = __mkntpath(path, name)) == -1) return NULL;
return opendir_nt_impl(name, len);
}
static textwindows noinline DIR *fdopendir_nt(int fd) {
DIR *res;
char16_t name[PATH_MAX];
if (__isfdkind(fd, kFdFile)) {
if ((res = opendir_nt_impl(
name, GetFinalPathNameByHandle(
g_fds.p[fd].handle, name, ARRAYLEN(name),
kNtFileNameNormalized | kNtVolumeNameDos)))) {
close(fd);
return res;
}
} else {
ebadf();
}
return NULL;
}
static textwindows noinline struct dirent *readdir_nt(DIR *dir) {
if (!dir->isdone) {
memset(&dir->ent, 0, sizeof(dir->ent));
dir->ent.d_ino = 0;
dir->ent.d_off = dir->tell++;
dir->ent.d_reclen = sizeof(dir->ent) +
tprecode16to8(dir->ent.d_name, sizeof(dir->ent.d_name),
dir->windata.cFileName)
.ax +
1;
switch (dir->windata.dwFileType) {
case kNtFileTypeDisk:
dir->ent.d_type = DT_BLK;
break;
case kNtFileTypeChar:
dir->ent.d_type = DT_CHR;
break;
case kNtFileTypePipe:
dir->ent.d_type = DT_FIFO;
break;
default:
if (dir->windata.dwFileAttributes & kNtFileAttributeDirectory) {
dir->ent.d_type = DT_DIR;
} else {
dir->ent.d_type = DT_REG;
}
break;
}
dir->isdone = !FindNextFile(dir->fd, &dir->windata);
return &dir->ent;
} else {
return NULL;
}
}
/**
* Opens directory, e.g.
*
* DIR *d;
* struct dirent *e;
* CHECK((d = opendir(path)));
* while ((e = readdir(d))) {
* printf("%s/%s\n", path, e->d_name);
* }
* LOGIFNEG1(closedir(d));
*
* @returns newly allocated DIR object, or NULL w/ errno
* @errors ENOENT, ENOTDIR, EACCES, EMFILE, ENFILE, ENOMEM
* @see glob()
*/
DIR *opendir(const char *name) {
int fd;
DIR *res;
if (!IsWindows()) {
res = NULL;
if ((fd = open(name, O_RDONLY | O_DIRECTORY | O_CLOEXEC)) != -1) {
if (!(res = fdopendir(fd))) close(fd);
}
return res;
} else {
return opendir_nt(name);
}
}
/**
* Creates directory object for file descriptor.
*
* @param fd gets owned by this function, if it succeeds
* @return new directory object, which must be freed by closedir(),
* or NULL w/ errno
* @errors ENOMEM and fd is closed
*/
DIR *fdopendir(int fd) {
DIR *dir;
if (!IsWindows()) {
if (!(dir = calloc(1, sizeof(*dir)))) return NULL;
dir->fd = fd;
return dir;
} else {
return fdopendir_nt(fd);
}
}
/**
* Reads next entry from directory stream.
*
* This API doesn't define any particular ordering.
*
* @param dir is the object opendir() or fdopendir() returned
* @return next entry or NULL on end or error, which can be
* differentiated by setting errno to 0 beforehand
*/
struct dirent *readdir(DIR *dir) {
int rc;
long basep;
struct dirent *ent;
struct dirent_bsd *bsd;
struct dirent_netbsd *nbsd;
struct dirent_openbsd *obsd;
if (!IsWindows()) {
if (dir->buf_pos >= dir->buf_end) {
basep = dir->tell; /* TODO(jart): what does xnu do */
rc = getdents(dir->fd, dir->buf, sizeof(dir->buf) - 256, &basep);
if (!rc || rc == -1) return NULL;
dir->buf_pos = 0;
dir->buf_end = rc;
}
if (IsLinux()) {
ent = (struct dirent *)(dir->buf + dir->buf_pos);
dir->buf_pos += ent->d_reclen;
dir->tell = ent->d_off;
} else if (IsOpenbsd()) {
obsd = (struct dirent_openbsd *)(dir->buf + dir->buf_pos);
dir->buf_pos += obsd->d_reclen;
ent = &dir->ent;
ent->d_ino = obsd->d_fileno;
ent->d_off = obsd->d_off;
ent->d_reclen = obsd->d_reclen;
ent->d_type = obsd->d_type;
memcpy(ent->d_name, obsd->d_name, obsd->d_namlen + 1);
} else if (IsNetbsd()) {
nbsd = (struct dirent_netbsd *)(dir->buf + dir->buf_pos);
dir->buf_pos += nbsd->d_reclen;
ent = &dir->ent;
ent->d_ino = nbsd->d_fileno;
ent->d_off = dir->tell++;
ent->d_reclen = nbsd->d_reclen;
ent->d_type = nbsd->d_type;
memcpy(ent->d_name, nbsd->d_name, MAX(256, nbsd->d_namlen + 1));
} else {
bsd = (struct dirent_bsd *)(dir->buf + dir->buf_pos);
dir->buf_pos += bsd->d_reclen;
ent = &dir->ent;
ent->d_ino = bsd->d_fileno;
ent->d_off = IsXnu() ? (dir->tell = basep) : dir->tell++;
ent->d_reclen = bsd->d_reclen;
ent->d_type = bsd->d_type;
memcpy(ent->d_name, bsd->d_name, bsd->d_namlen + 1);
}
return ent;
} else {
return readdir_nt(dir);
}
}
/**
* Closes directory object returned by opendir().
* @return 0 on success or -1 w/ errno
*/
int closedir(DIR *dir) {
int rc;
if (dir) {
if (!IsWindows()) {
rc = close(dir->fd);
} else {
rc = FindClose(dir->fd) ? 0 : __winerr();
}
free(dir);
} else {
rc = 0;
}
return rc;
}
/**
* Returns offset into directory data.
*/
long telldir(DIR *dir) {
return dir->tell;
}
/**
* Returns file descriptor associated with DIR object.
*/
int dirfd(DIR *dir) {
if (IsWindows()) return eopnotsupp();
return dir->fd;
}