git/compat/mingw.h
Jeff King 2b08101204 Makefile: add OPEN_RETURNS_EINTR knob
On some platforms, open() reportedly returns EINTR when opening regular
files and we receive a signal (usually SIGALRM from our progress meter).
This shouldn't happen, as open() should be a restartable syscall, and we
specify SA_RESTART when setting up the alarm handler. So it may actually
be a kernel or libc bug for this to happen. But it has been reported on
at least one version of Linux (on a network filesystem):

  https://lore.kernel.org/git/c8061cce-71e4-17bd-a56a-a5fed93804da@neanderfunk.de/

as well as on macOS starting with Big Sur even on a regular filesystem.

We can work around it by retrying open() calls that get EINTR, just as
we do for read(), etc. Since we don't ever _want_ to interrupt an open()
call, we can get away with just redefining open, rather than insisting
all callsites use xopen().

We actually do have an xopen() wrapper already (and it even does this
retry, though there's no indication of it being an observed problem back
then; it seems simply to have been lifted from xread(), etc). But it is
used hardly anywhere, and isn't suitable for general use because it will
die() on error. In theory we could combine the two, but it's awkward to
do so because of the variable-args interface of open().

This patch adds a Makefile knob for enabling the workaround. It's not
enabled by default for any platforms in config.mak.uname yet, as we
don't have enough data to decide how common this is (I have not been
able to reproduce on either Linux or Big Sur myself). It may be worth
enabling preemptively anyway, since the cost is pretty low (if we don't
see an EINTR, it's just an extra conditional).

However, note that we must not enable this on Windows. It doesn't do
anything there, and the macro overrides the existing mingw_open()
redirection. I've added a preemptive #undef here in the mingw header
(which is processed first) to just quietly disable it (we could also
make it an #error, but there is little point in being so aggressive).

Reported-by: Aleksey Kliger <alklig@microsoft.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-26 14:15:51 -08:00

615 lines
17 KiB
C

#ifdef __MINGW64_VERSION_MAJOR
#include <stdint.h>
#include <wchar.h>
typedef _sigset_t sigset_t;
#endif
#include <winsock2.h>
#include <ws2tcpip.h>
/* MinGW-w64 reports to have flockfile, but it does not actually have it. */
#ifdef __MINGW64_VERSION_MAJOR
#undef _POSIX_THREAD_SAFE_FUNCTIONS
#endif
int mingw_core_config(const char *var, const char *value, void *cb);
#define platform_core_config mingw_core_config
/*
* things that are not available in header files
*/
typedef int uid_t;
typedef int socklen_t;
#ifndef __MINGW64_VERSION_MAJOR
typedef int pid_t;
#define hstrerror strerror
#endif
#define S_IFLNK 0120000 /* Symbolic link */
#define S_ISLNK(x) (((x) & S_IFMT) == S_IFLNK)
#define S_ISSOCK(x) 0
#ifndef S_IRWXG
#define S_IRGRP 0
#define S_IWGRP 0
#define S_IXGRP 0
#define S_IRWXG (S_IRGRP | S_IWGRP | S_IXGRP)
#endif
#ifndef S_IRWXO
#define S_IROTH 0
#define S_IWOTH 0
#define S_IXOTH 0
#define S_IRWXO (S_IROTH | S_IWOTH | S_IXOTH)
#endif
#define S_ISUID 0004000
#define S_ISGID 0002000
#define S_ISVTX 0001000
#define WIFEXITED(x) 1
#define WIFSIGNALED(x) 0
#define WEXITSTATUS(x) ((x) & 0xff)
#define WTERMSIG(x) SIGTERM
#ifndef EWOULDBLOCK
#define EWOULDBLOCK EAGAIN
#endif
#ifndef ELOOP
#define ELOOP EMLINK
#endif
#define SHUT_WR SD_SEND
#define SIGHUP 1
#define SIGQUIT 3
#define SIGKILL 9
#define SIGPIPE 13
#define SIGALRM 14
#define SIGCHLD 17
#define F_GETFD 1
#define F_SETFD 2
#define FD_CLOEXEC 0x1
#if !defined O_CLOEXEC && defined O_NOINHERIT
#define O_CLOEXEC O_NOINHERIT
#endif
#ifndef EAFNOSUPPORT
#define EAFNOSUPPORT WSAEAFNOSUPPORT
#endif
#ifndef ECONNABORTED
#define ECONNABORTED WSAECONNABORTED
#endif
#ifndef ENOTSOCK
#define ENOTSOCK WSAENOTSOCK
#endif
struct passwd {
char *pw_name;
char *pw_gecos;
char *pw_dir;
};
typedef void (__cdecl *sig_handler_t)(int);
struct sigaction {
sig_handler_t sa_handler;
unsigned sa_flags;
};
#define SA_RESTART 0
struct itimerval {
struct timeval it_value, it_interval;
};
#define ITIMER_REAL 0
struct utsname {
char sysname[16];
char nodename[1];
char release[16];
char version[16];
char machine[1];
};
/*
* sanitize preprocessor namespace polluted by Windows headers defining
* macros which collide with git local versions
*/
#undef HELP_COMMAND /* from winuser.h */
/*
* trivial stubs
*/
static inline int readlink(const char *path, char *buf, size_t bufsiz)
{ errno = ENOSYS; return -1; }
static inline int symlink(const char *oldpath, const char *newpath)
{ errno = ENOSYS; return -1; }
static inline int fchmod(int fildes, mode_t mode)
{ errno = ENOSYS; return -1; }
#ifndef __MINGW64_VERSION_MAJOR
static inline pid_t fork(void)
{ errno = ENOSYS; return -1; }
#endif
static inline unsigned int alarm(unsigned int seconds)
{ return 0; }
static inline int fsync(int fd)
{ return _commit(fd); }
static inline void sync(void)
{}
static inline uid_t getuid(void)
{ return 1; }
static inline struct passwd *getpwnam(const char *name)
{ return NULL; }
static inline int fcntl(int fd, int cmd, ...)
{
if (cmd == F_GETFD || cmd == F_SETFD)
return 0;
errno = EINVAL;
return -1;
}
#define sigemptyset(x) (void)0
static inline int sigaddset(sigset_t *set, int signum)
{ return 0; }
#define SIG_BLOCK 0
#define SIG_UNBLOCK 0
static inline int sigprocmask(int how, const sigset_t *set, sigset_t *oldset)
{ return 0; }
static inline pid_t getppid(void)
{ return 1; }
static inline pid_t getpgid(pid_t pid)
{ return pid == 0 ? getpid() : pid; }
static inline pid_t tcgetpgrp(int fd)
{ return getpid(); }
/*
* simple adaptors
*/
int mingw_mkdir(const char *path, int mode);
#define mkdir mingw_mkdir
#define WNOHANG 1
pid_t waitpid(pid_t pid, int *status, int options);
#define kill mingw_kill
int mingw_kill(pid_t pid, int sig);
#ifndef NO_OPENSSL
#include <openssl/ssl.h>
static inline int mingw_SSL_set_fd(SSL *ssl, int fd)
{
return SSL_set_fd(ssl, _get_osfhandle(fd));
}
#define SSL_set_fd mingw_SSL_set_fd
static inline int mingw_SSL_set_rfd(SSL *ssl, int fd)
{
return SSL_set_rfd(ssl, _get_osfhandle(fd));
}
#define SSL_set_rfd mingw_SSL_set_rfd
static inline int mingw_SSL_set_wfd(SSL *ssl, int fd)
{
return SSL_set_wfd(ssl, _get_osfhandle(fd));
}
#define SSL_set_wfd mingw_SSL_set_wfd
#endif
/*
* implementations of missing functions
*/
int pipe(int filedes[2]);
unsigned int sleep (unsigned int seconds);
int mkstemp(char *template);
int gettimeofday(struct timeval *tv, void *tz);
#ifndef __MINGW64_VERSION_MAJOR
struct tm *gmtime_r(const time_t *timep, struct tm *result);
struct tm *localtime_r(const time_t *timep, struct tm *result);
#endif
int getpagesize(void); /* defined in MinGW's libgcc.a */
struct passwd *getpwuid(uid_t uid);
int setitimer(int type, struct itimerval *in, struct itimerval *out);
int sigaction(int sig, struct sigaction *in, struct sigaction *out);
int link(const char *oldpath, const char *newpath);
int uname(struct utsname *buf);
/*
* replacements of existing functions
*/
int mingw_unlink(const char *pathname);
#define unlink mingw_unlink
int mingw_rmdir(const char *path);
#define rmdir mingw_rmdir
int mingw_open (const char *filename, int oflags, ...);
#define open mingw_open
#undef OPEN_RETURNS_EINTR
int mingw_fgetc(FILE *stream);
#define fgetc mingw_fgetc
FILE *mingw_fopen (const char *filename, const char *otype);
#define fopen mingw_fopen
FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream);
#define freopen mingw_freopen
int mingw_fflush(FILE *stream);
#define fflush mingw_fflush
ssize_t mingw_write(int fd, const void *buf, size_t len);
#define write mingw_write
int mingw_access(const char *filename, int mode);
#undef access
#define access mingw_access
int mingw_chdir(const char *dirname);
#define chdir mingw_chdir
int mingw_chmod(const char *filename, int mode);
#define chmod mingw_chmod
char *mingw_mktemp(char *template);
#define mktemp mingw_mktemp
char *mingw_getcwd(char *pointer, int len);
#define getcwd mingw_getcwd
#ifdef NO_UNSETENV
#error "NO_UNSETENV is incompatible with the Windows-specific startup code!"
#endif
/*
* We bind *env() routines (even the mingw_ ones) to private mingw_ versions.
* These talk to the CRT using UNICODE/wchar_t, but maintain the original
* narrow-char API.
*
* Note that the MSCRT maintains both ANSI (getenv()) and UNICODE (_wgetenv())
* routines and stores both versions of each environment variable in parallel
* (and secretly updates both when you set one or the other), but it uses CP_ACP
* to do the conversion rather than CP_UTF8.
*
* Since everything in the git code base is UTF8, we define the mingw_ routines
* to access the CRT using the UNICODE routines and manually convert them to
* UTF8. This also avoids round-trip problems.
*
* This also helps with our linkage, since "_wenviron" is publicly exported
* from the CRT. But to access "_environ" we would have to statically link
* to the CRT (/MT).
*
* We require NO_SETENV (and let gitsetenv() call our mingw_putenv).
*/
#define getenv mingw_getenv
#define putenv mingw_putenv
#define unsetenv mingw_putenv
char *mingw_getenv(const char *name);
int mingw_putenv(const char *name);
int mingw_gethostname(char *host, int namelen);
#define gethostname mingw_gethostname
struct hostent *mingw_gethostbyname(const char *host);
#define gethostbyname mingw_gethostbyname
int mingw_getaddrinfo(const char *node, const char *service,
const struct addrinfo *hints, struct addrinfo **res);
#define getaddrinfo mingw_getaddrinfo
int mingw_socket(int domain, int type, int protocol);
#define socket mingw_socket
int mingw_connect(int sockfd, struct sockaddr *sa, size_t sz);
#define connect mingw_connect
int mingw_bind(int sockfd, struct sockaddr *sa, size_t sz);
#define bind mingw_bind
int mingw_setsockopt(int sockfd, int lvl, int optname, void *optval, int optlen);
#define setsockopt mingw_setsockopt
int mingw_shutdown(int sockfd, int how);
#define shutdown mingw_shutdown
int mingw_listen(int sockfd, int backlog);
#define listen mingw_listen
int mingw_accept(int sockfd, struct sockaddr *sa, socklen_t *sz);
#define accept mingw_accept
int mingw_rename(const char*, const char*);
#define rename mingw_rename
#if defined(USE_WIN32_MMAP) || defined(_MSC_VER)
int mingw_getpagesize(void);
#define getpagesize mingw_getpagesize
#endif
struct rlimit {
unsigned int rlim_cur;
};
#define RLIMIT_NOFILE 0
static inline int getrlimit(int resource, struct rlimit *rlp)
{
if (resource != RLIMIT_NOFILE) {
errno = EINVAL;
return -1;
}
rlp->rlim_cur = 2048;
return 0;
}
/*
* Use mingw specific stat()/lstat()/fstat() implementations on Windows,
* including our own struct stat with 64 bit st_size and nanosecond-precision
* file times.
*/
#ifndef __MINGW64_VERSION_MAJOR
#define off_t off64_t
#define lseek _lseeki64
#ifndef _MSC_VER
struct timespec {
time_t tv_sec;
long tv_nsec;
};
#endif
#endif
struct mingw_stat {
_dev_t st_dev;
_ino_t st_ino;
_mode_t st_mode;
short st_nlink;
short st_uid;
short st_gid;
_dev_t st_rdev;
off64_t st_size;
struct timespec st_atim;
struct timespec st_mtim;
struct timespec st_ctim;
};
#define st_atime st_atim.tv_sec
#define st_mtime st_mtim.tv_sec
#define st_ctime st_ctim.tv_sec
#ifdef stat
#undef stat
#endif
#define stat mingw_stat
int mingw_lstat(const char *file_name, struct stat *buf);
int mingw_stat(const char *file_name, struct stat *buf);
int mingw_fstat(int fd, struct stat *buf);
#ifdef fstat
#undef fstat
#endif
#define fstat mingw_fstat
#ifdef lstat
#undef lstat
#endif
#define lstat mingw_lstat
int mingw_utime(const char *file_name, const struct utimbuf *times);
#define utime mingw_utime
size_t mingw_strftime(char *s, size_t max,
const char *format, const struct tm *tm);
#define strftime mingw_strftime
pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **env,
const char *dir,
int fhin, int fhout, int fherr);
int mingw_execvp(const char *cmd, char *const *argv);
#define execvp mingw_execvp
int mingw_execv(const char *cmd, char *const *argv);
#define execv mingw_execv
static inline unsigned int git_ntohl(unsigned int x)
{ return (unsigned int)ntohl(x); }
#define ntohl git_ntohl
sig_handler_t mingw_signal(int sig, sig_handler_t handler);
#define signal mingw_signal
int mingw_raise(int sig);
#define raise mingw_raise
/*
* ANSI emulation wrappers
*/
int winansi_isatty(int fd);
#define isatty winansi_isatty
int winansi_dup2(int oldfd, int newfd);
#define dup2 winansi_dup2
void winansi_init(void);
HANDLE winansi_get_osfhandle(int fd);
/*
* git specific compatibility
*/
static inline void convert_slashes(char *path)
{
for (; *path; path++)
if (*path == '\\')
*path = '/';
}
#define PATH_SEP ';'
char *mingw_query_user_email(void);
#define query_user_email mingw_query_user_email
#if !defined(__MINGW64_VERSION_MAJOR) && (!defined(_MSC_VER) || _MSC_VER < 1800)
#define PRIuMAX "I64u"
#define PRId64 "I64d"
#else
#include <inttypes.h>
#endif
/**
* Verifies that the given path is a valid one on Windows.
*
* In particular, path segments are disallowed which
*
* - end in a period or a space (except the special directories `.` and `..`).
*
* - contain any of the reserved characters, e.g. `:`, `;`, `*`, etc
*
* - correspond to reserved names (such as `AUX`, `PRN`, etc)
*
* The `allow_literal_nul` parameter controls whether the path `NUL` should
* be considered valid (this makes sense e.g. before opening files, as it is
* perfectly legitimate to open `NUL` on Windows, just as it is to open
* `/dev/null` on Unix/Linux).
*
* Returns 1 upon success, otherwise 0.
*/
int is_valid_win32_path(const char *path, int allow_literal_nul);
#define is_valid_path(path) is_valid_win32_path(path, 0)
/**
* Converts UTF-8 encoded string to UTF-16LE.
*
* To support repositories with legacy-encoded file names, invalid UTF-8 bytes
* 0xa0 - 0xff are converted to corresponding printable Unicode chars \u00a0 -
* \u00ff, and invalid UTF-8 bytes 0x80 - 0x9f (which would make non-printable
* Unicode) are converted to hex-code.
*
* Lead-bytes not followed by an appropriate number of trail-bytes, over-long
* encodings and 4-byte encodings > \u10ffff are detected as invalid UTF-8.
*
* Maximum space requirement for the target buffer is two wide chars per UTF-8
* char (((strlen(utf) * 2) + 1) [* sizeof(wchar_t)]).
*
* The maximum space is needed only if the entire input string consists of
* invalid UTF-8 bytes in range 0x80-0x9f, as per the following table:
*
* | | UTF-8 | UTF-16 |
* Code point | UTF-8 sequence | bytes | words | ratio
* --------------+-------------------+-------+--------+-------
* 000000-00007f | 0-7f | 1 | 1 | 1
* 000080-0007ff | c2-df + 80-bf | 2 | 1 | 0.5
* 000800-00ffff | e0-ef + 2 * 80-bf | 3 | 1 | 0.33
* 010000-10ffff | f0-f4 + 3 * 80-bf | 4 | 2 (a) | 0.5
* invalid | 80-9f | 1 | 2 (b) | 2
* invalid | a0-ff | 1 | 1 | 1
*
* (a) encoded as UTF-16 surrogate pair
* (b) encoded as two hex digits
*
* Note that, while the UTF-8 encoding scheme can be extended to 5-byte, 6-byte
* or even indefinite-byte sequences, the largest valid code point \u10ffff
* encodes as only 4 UTF-8 bytes.
*
* Parameters:
* wcs: wide char target buffer
* utf: string to convert
* wcslen: size of target buffer (in wchar_t's)
* utflen: size of string to convert, or -1 if 0-terminated
*
* Returns:
* length of converted string (_wcslen(wcs)), or -1 on failure
*
* Errors:
* EINVAL: one of the input parameters is invalid (e.g. NULL)
* ERANGE: the output buffer is too small
*/
int xutftowcsn(wchar_t *wcs, const char *utf, size_t wcslen, int utflen);
/**
* Simplified variant of xutftowcsn, assumes input string is \0-terminated.
*/
static inline int xutftowcs(wchar_t *wcs, const char *utf, size_t wcslen)
{
return xutftowcsn(wcs, utf, wcslen, -1);
}
/**
* Simplified file system specific variant of xutftowcsn, assumes output
* buffer size is MAX_PATH wide chars and input string is \0-terminated,
* fails with ENAMETOOLONG if input string is too long.
*/
static inline int xutftowcs_path(wchar_t *wcs, const char *utf)
{
int result = xutftowcsn(wcs, utf, MAX_PATH, -1);
if (result < 0 && errno == ERANGE)
errno = ENAMETOOLONG;
return result;
}
/**
* Converts UTF-16LE encoded string to UTF-8.
*
* Maximum space requirement for the target buffer is three UTF-8 chars per
* wide char ((_wcslen(wcs) * 3) + 1).
*
* The maximum space is needed only if the entire input string consists of
* UTF-16 words in range 0x0800-0xd7ff or 0xe000-0xffff (i.e. \u0800-\uffff
* modulo surrogate pairs), as per the following table:
*
* | | UTF-16 | UTF-8 |
* Code point | UTF-16 sequence | words | bytes | ratio
* --------------+-----------------------+--------+-------+-------
* 000000-00007f | 0000-007f | 1 | 1 | 1
* 000080-0007ff | 0080-07ff | 1 | 2 | 2
* 000800-00ffff | 0800-d7ff / e000-ffff | 1 | 3 | 3
* 010000-10ffff | d800-dbff + dc00-dfff | 2 | 4 | 2
*
* Note that invalid code points > 10ffff cannot be represented in UTF-16.
*
* Parameters:
* utf: target buffer
* wcs: wide string to convert
* utflen: size of target buffer
*
* Returns:
* length of converted string, or -1 on failure
*
* Errors:
* EINVAL: one of the input parameters is invalid (e.g. NULL)
* ERANGE: the output buffer is too small
*/
int xwcstoutf(char *utf, const wchar_t *wcs, size_t utflen);
/*
* A critical section used in the implementation of the spawn
* functions (mingw_spawnv[p]e()) and waitpid(). Initialised in
* the replacement main() macro below.
*/
extern CRITICAL_SECTION pinfo_cs;
/*
* Git, like most portable C applications, implements a main() function. On
* Windows, this main() function would receive parameters encoded in the
* current locale, but Git for Windows would prefer UTF-8 encoded parameters.
*
* To make that happen, we still declare main() here, and then declare and
* implement wmain() (which is the Unicode variant of main()) and compile with
* -municode. This wmain() function reencodes the parameters from UTF-16 to
* UTF-8 format, sets up a couple of other things as required on Windows, and
* then hands off to the main() function.
*/
int wmain(int argc, const wchar_t **w_argv);
int main(int argc, const char **argv);
/*
* For debugging: if a problem occurs, say, in a Git process that is spawned
* from another Git process which in turn is spawned from yet another Git
* process, it can be quite daunting to figure out what is going on.
*
* Call this function to open a new MinTTY (this assumes you are in Git for
* Windows' SDK) with a GDB that attaches to the current process right away.
*/
void open_in_gdb(void);
/*
* Used by Pthread API implementation for Windows
*/
int err_win_to_posix(DWORD winerr);