зеркало из https://github.com/microsoft/git.git
Win32: implement readlink()
Implement readlink() by reading NTFS reparse points. Works for symlinks and directory junctions. If symlinks are disabled, fail with ENOSYS. Signed-off-by: Karsten Blees <blees@dcon.de>
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Родитель
5f105e5e50
Коммит
8d3c55602d
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@ -4,6 +4,7 @@
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#include <sddl.h>
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#include <conio.h>
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#include <wchar.h>
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#include <winioctl.h>
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#include "../strbuf.h"
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#include "../run-command.h"
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#include "../cache.h"
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@ -2724,6 +2725,103 @@ int link(const char *oldpath, const char *newpath)
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return 0;
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}
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#ifndef _WINNT_H
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/*
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* The REPARSE_DATA_BUFFER structure is defined in the Windows DDK (in
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* ntifs.h) and in MSYS1's winnt.h (which defines _WINNT_H). So define
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* it ourselves if we are on MSYS2 (whose winnt.h defines _WINNT_).
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*/
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typedef struct _REPARSE_DATA_BUFFER {
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DWORD ReparseTag;
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WORD ReparseDataLength;
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WORD Reserved;
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#ifndef _MSC_VER
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_ANONYMOUS_UNION
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#endif
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union {
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struct {
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WORD SubstituteNameOffset;
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WORD SubstituteNameLength;
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WORD PrintNameOffset;
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WORD PrintNameLength;
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ULONG Flags;
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WCHAR PathBuffer[1];
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} SymbolicLinkReparseBuffer;
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struct {
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WORD SubstituteNameOffset;
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WORD SubstituteNameLength;
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WORD PrintNameOffset;
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WORD PrintNameLength;
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WCHAR PathBuffer[1];
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} MountPointReparseBuffer;
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struct {
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BYTE DataBuffer[1];
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} GenericReparseBuffer;
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} DUMMYUNIONNAME;
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} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
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#endif
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int readlink(const char *path, char *buf, size_t bufsiz)
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{
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HANDLE handle;
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WCHAR wpath[MAX_LONG_PATH], *wbuf;
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REPARSE_DATA_BUFFER *b = alloca(MAXIMUM_REPARSE_DATA_BUFFER_SIZE);
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DWORD dummy;
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char tmpbuf[MAX_LONG_PATH];
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int len;
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if (xutftowcs_long_path(wpath, path) < 0)
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return -1;
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/* read reparse point data */
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handle = CreateFileW(wpath, 0,
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FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
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OPEN_EXISTING,
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FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, NULL);
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if (handle == INVALID_HANDLE_VALUE) {
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errno = err_win_to_posix(GetLastError());
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return -1;
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}
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if (!DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, NULL, 0, b,
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MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &dummy, NULL)) {
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errno = err_win_to_posix(GetLastError());
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CloseHandle(handle);
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return -1;
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}
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CloseHandle(handle);
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/* get target path for symlinks or mount points (aka 'junctions') */
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switch (b->ReparseTag) {
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case IO_REPARSE_TAG_SYMLINK:
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wbuf = (WCHAR*) (((char*) b->SymbolicLinkReparseBuffer.PathBuffer)
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+ b->SymbolicLinkReparseBuffer.SubstituteNameOffset);
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*(WCHAR*) (((char*) wbuf)
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+ b->SymbolicLinkReparseBuffer.SubstituteNameLength) = 0;
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break;
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case IO_REPARSE_TAG_MOUNT_POINT:
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wbuf = (WCHAR*) (((char*) b->MountPointReparseBuffer.PathBuffer)
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+ b->MountPointReparseBuffer.SubstituteNameOffset);
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*(WCHAR*) (((char*) wbuf)
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+ b->MountPointReparseBuffer.SubstituteNameLength) = 0;
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break;
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default:
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errno = EINVAL;
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return -1;
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}
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/*
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* Adapt to strange readlink() API: Copy up to bufsiz *bytes*, potentially
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* cutting off a UTF-8 sequence. Insufficient bufsize is *not* a failure
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* condition. There is no conversion function that produces invalid UTF-8,
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* so convert to a (hopefully large enough) temporary buffer, then memcpy
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* the requested number of bytes (including '\0' for robustness).
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*/
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if ((len = xwcstoutf(tmpbuf, normalize_ntpath(wbuf), MAX_LONG_PATH)) < 0)
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return -1;
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memcpy(buf, tmpbuf, min(bufsiz, len + 1));
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return min(bufsiz, len);
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}
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pid_t waitpid(pid_t pid, int *status, int options)
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{
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HANDLE h = OpenProcess(SYNCHRONIZE | PROCESS_QUERY_INFORMATION,
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@ -125,8 +125,6 @@ struct utsname {
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* trivial stubs
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*/
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static inline int readlink(const char *path, char *buf, size_t bufsiz)
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{ errno = ENOSYS; return -1; }
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static inline int symlink(const char *oldpath, const char *newpath)
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{ errno = ENOSYS; return -1; }
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static inline int fchmod(int fildes, mode_t mode)
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@ -219,6 +217,7 @@ int setitimer(int type, struct itimerval *in, struct itimerval *out);
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int sigaction(int sig, struct sigaction *in, struct sigaction *out);
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int link(const char *oldpath, const char *newpath);
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int uname(struct utsname *buf);
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int readlink(const char *path, char *buf, size_t bufsiz);
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/*
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* replacements of existing functions
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