@@ -1,3 +1,13 @@
+2016-10-29 Eli Zaretskii <eliz@gnu.org>
+
+ * NEWS: Mention support for redirection on MS-Windows.
+
+ * windows-nat.c (redir_open, redir_set_redirection)
+ (redirect_inferior_handles) [!__CYGWIN__]: New functions.
+ (windows_create_inferior) [!__CYGWIN__]: Use
+ 'redirect_inferior_handles' to redirect standard handles of the
+ debuggee if the command line requests that.
+
2016-10-28 Pedro Alves <palves@redhat.com>
* Makefile.in (CXX_DIALECT): Get from configure.
@@ -9,6 +9,14 @@
compiler. The --disable-build-with-cxx configure option has been
removed.
+* Native debugging on MS-Windows supports command-line redirection
+
+ Command-line arguments used for starting programs on MS-Windows can
+ now include redirection symbols supported by native Windows shells,
+ such as '<', '>', '>>', '2>&1', etc. This affects GDB commands such
+ as "run", "start", and "set args", as well as the corresponding MI
+ features.
+
* Support for thread names on MS-Windows.
GDB now catches and handles the special exception that programs
@@ -2116,6 +2116,301 @@ clear_win32_environment (char **env)
}
#endif
+#ifndef __CYGWIN__
+
+/* Redirection of inferior I/O streams for native MS-Windows programs.
+ Unlike on Unix, where this is handled by invoking the inferior via
+ the shell, on MS-Windows we need to emulate the cmd.exe shell.
+
+ The official documentation of the cmd.exe redirection features is here:
+
+ http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/redirection.mspx
+
+ (That page talks about Windows XP, but there's no newer
+ documentation, so we assume later versions of cmd.exe didn't change
+ anything.)
+
+ Caveat: the documentation on that page seems to include a few lies.
+ For example, it describes strange constructs 1<&2 and 2<&1, which
+ seem to work only when 1>&2 resp. 2>&1 would make sense, and so I
+ think the cmd.exe parser of the redirection symbols simply doesn't
+ care about the < vs > distinction in these cases. Therefore, the
+ supported features are explicitly documented below.
+
+ The emulation below aims at supporting all the valid use cases
+ supported by cmd.exe, which include:
+
+ < FILE redirect standard input from FILE
+ 0< FILE redirect standard input from FILE
+ <&N redirect standard input from file descriptor N
+ 0<&N redirect standard input from file descriptor N
+ > FILE redirect standard output to FILE
+ >> FILE append standard output to FILE
+ 1>> FILE append standard output to FILE
+ >&N redirect standard output to file descriptor N
+ 1>&N redirect standard output to file descriptor N
+ >>&N append standard output to file descriptor N
+ 1>>&N append standard output to file descriptor N
+ 2> FILE redirect standard error to FILE
+ 2>> FILE append standard error to FILE
+ 2>&N redirect standard error to file descriptor N
+ 2>>&N append standard error to file descriptor N
+
+ Note that using N > 2 in the above construct is supported, but
+ requires that the corresponding file descriptor be open by some
+ means elsewhere or outside GDB. Also note that using ">&0" or
+ "<&2" will generally fail, because the file descriptor redirected
+ from is normally open in an incompatible mode (e.g., FD 0 is open
+ for reading only). IOW, use of such tricks is not recommended;
+ you are on your own.
+
+ We do NOT support redirection of file descriptors above 2, as in
+ "3>SOME-FILE", because MinGW compiled programs don't (supporting
+ that needs special handling in the startup code that MinGW
+ doesn't have). Pipes are also not supported.
+
+ As for invalid use cases, where the redirection contains some
+ error, the emulation below will detect that and produce some
+ error and/or failure. But the behavior in those cases is not
+ bug-for-bug compatible with what cmd.exe does in those cases.
+ That's because what cmd.exe does then is not well defined, and
+ seems to be a side effect of the cmd.exe parsing of the command
+ line more than anything else. For example, try redirecting to an
+ invalid file name, as in "> foo:bar".
+
+ There are also minor syntactic deviations from what cmd.exe does
+ in some corner cases. For example, it doesn't support the likes
+ of "> &foo" to mean redirect to file named literally "&foo"; we
+ do support that here, because that, too, sounds like some issue
+ with the cmd.exe parser. Another nicety is that we support
+ redirection targets that use file names with forward slashes,
+ something cmd.exe doesn't -- this comes in handy since GDB
+ file-name completion can be used when typing the command line for
+ the inferior. */
+
+/* Support routines for redirecting standard handles of the inferior. */
+
+/* Parse a single redirection spec, open/duplicate the specified
+ file/fd, and assign the appropriate value to one of the 3 standard
+ file descriptors. */
+static int
+redir_open (const char *redir_string, int *inp, int *out, int *err)
+{
+ int *fd, ref_fd = -2;
+ int mode;
+ const char *fname = redir_string + 1;
+ int rc = *redir_string;
+
+ switch (rc)
+ {
+ case '0':
+ fname++;
+ /* FALLTHROUGH */
+ case '<':
+ fd = inp;
+ mode = O_RDONLY;
+ break;
+ case '1': case '2':
+ fname++;
+ /* FALLTHROUGH */
+ case '>':
+ fd = (rc == '2') ? err : out;
+ mode = O_WRONLY | O_CREAT;
+ if (*fname == '>')
+ {
+ fname++;
+ mode |= O_APPEND;
+ }
+ else
+ mode |= O_TRUNC;
+ break;
+ default:
+ return -1;
+ }
+
+ if (*fname == '&' && '0' <= fname[1] && fname[1] <= '9')
+ {
+ /* A reference to a file descriptor. */
+ char *fdtail;
+ ref_fd = (int) strtol (fname + 1, &fdtail, 10);
+ if (fdtail > fname + 1 && *fdtail == '\0')
+ {
+ /* Don't allow redirection when open modes are incompatible. */
+ if ((ref_fd == 0 && (fd == out || fd == err))
+ || ((ref_fd == 1 || ref_fd == 2) && fd == inp))
+ {
+ errno = EPERM;
+ return -1;
+ }
+ if (ref_fd == 0)
+ ref_fd = *inp;
+ else if (ref_fd == 1)
+ ref_fd = *out;
+ else if (ref_fd == 2)
+ ref_fd = *err;
+ }
+ else
+ {
+ errno = EBADF;
+ return -1;
+ }
+ }
+ else
+ fname++; /* skip the separator space */
+ /* If the descriptor is already open, close it. This allows
+ multiple specs of redirections for the same stream, which is
+ somewhat nonsensical, but still valid and supported by cmd.exe.
+ (But cmd.exe only opens a single file in this case, the one
+ specified by the last redirection spec on the command line.) */
+ if (*fd >= 0)
+ _close (*fd);
+ if (ref_fd == -2)
+ {
+ *fd = _open (fname, mode, _S_IREAD | _S_IWRITE);
+ if (*fd < 0)
+ return -1;
+ }
+ else if (ref_fd == -1)
+ *fd = -1; /* reset to default destination */
+ else
+ {
+ *fd = _dup (ref_fd);
+ if (*fd < 0)
+ return -1;
+ }
+ /* _open just sets a flag for O_APPEND, which won't be passed to the
+ inferior, so we need to actually move the file pointer. */
+ if ((mode & O_APPEND) != 0)
+ _lseek (*fd, 0L, SEEK_END);
+ return 0;
+}
+
+/* Canonicalize a single redirection spec and set up the corresponding
+ file descriptor as specified. */
+static int
+redir_set_redirection (const char *s, int *inp, int *out, int *err)
+{
+ char buf[__PMAX + 2 + 5]; /* extra space for quotes & redirection string */
+ char *d = buf;
+ const char *start = s;
+ int quote = 0;
+
+ *d++ = *s++; /* copy the 1st character, < or > or a digit */
+ if ((*start == '>' || *start == '1' || *start == '2')
+ && *s == '>')
+ {
+ *d++ = *s++;
+ if (*s == '>' && *start != '>')
+ *d++ = *s++;
+ }
+ else if (*start == '0' && *s == '<')
+ *d++ = *s++;
+ /* cmd.exe recognizes "&N" only immediately after the redirection symbol. */
+ if (*s != '&')
+ {
+ while (isspace (*s)) /* skip whitespace before file name */
+ s++;
+ *d++ = ' '; /* separate file name with a single space */
+ }
+
+ /* Copy the file name. */
+ while (*s)
+ {
+ /* Remove quoting characters from the file name in buf[]. */
+ if (*s == '"') /* could support '..' quoting here */
+ {
+ if (!quote)
+ quote = *s++;
+ else if (*s == quote)
+ {
+ quote = 0;
+ s++;
+ }
+ else
+ *d++ = *s++;
+ }
+ else if (*s == '\\')
+ {
+ if (s[1] == '"') /* could support '..' here */
+ s++;
+ *d++ = *s++;
+ }
+ else if (isspace (*s) && !quote)
+ break;
+ else
+ *d++ = *s++;
+ if (d - buf >= sizeof (buf) - 1)
+ {
+ errno = ENAMETOOLONG;
+ return 0;
+ }
+ }
+ *d = '\0';
+
+ /* Windows doesn't allow redirection characters in file names, so we
+ can bail out early if they use them, or if there's no target file
+ name after the redirection symbol. */
+ if (d[-1] == '>' || d[-1] == '<')
+ {
+ errno = ENOENT;
+ return 0;
+ }
+ if (redir_open (buf, inp, out, err) == 0)
+ return s - start;
+ return 0;
+}
+
+/* Parse the command line for redirection specs and prepare the file
+ descriptors for the 3 standard streams accordingly. */
+static bool
+redirect_inferior_handles (const char *cmd_orig, char *cmd,
+ int *inp, int *out, int *err)
+{
+ const char *s = cmd_orig;
+ char *d = cmd;
+ int quote = 0;
+ bool retval = false;
+
+ while (isspace (*s))
+ *d++ = *s++;
+
+ while (*s)
+ {
+ if (*s == '"') /* could also support '..' quoting here */
+ {
+ if (!quote)
+ quote = *s;
+ else if (*s == quote)
+ quote = 0;
+ }
+ else if (*s == '\\')
+ {
+ if (s[1] == '"') /* escaped quote char */
+ s++;
+ }
+ else if (!quote)
+ {
+ /* Process a single redirection candidate. */
+ if (*s == '<' || *s == '>'
+ || ((*s == '1' || *s == '2') && s[1] == '>')
+ || (*s == '0' && s[1] == '<'))
+ {
+ int skip = redir_set_redirection (s, inp, out, err);
+
+ if (skip <= 0)
+ return false;
+ retval = true;
+ s += skip;
+ }
+ }
+ if (*s)
+ *d++ = *s++;
+ }
+ *d = '\0';
+ return retval;
+}
+#endif /* !__CYGWIN__ */
+
/* Start an inferior windows child process and sets inferior_ptid to its pid.
EXEC_FILE is the file to run.
ALLARGS is a string containing the arguments to the program.
@@ -2138,20 +2433,25 @@ windows_create_inferior (struct target_ops *ops, char *exec_file,
size_t len;
int tty;
int ostdin, ostdout, ostderr;
-#else
+#else /* !__CYGWIN__ */
char real_path[__PMAX];
char shell[__PMAX]; /* Path to shell */
char *toexec;
- char *args;
- size_t args_len;
- HANDLE tty;
+ char *args, *allargs_copy;
+ size_t args_len, allargs_len;
+ int fd_inp = -1, fd_out = -1, fd_err = -1;
+ HANDLE tty = INVALID_HANDLE_VALUE;
+ HANDLE inf_stdin = INVALID_HANDLE_VALUE;
+ HANDLE inf_stdout = INVALID_HANDLE_VALUE;
+ HANDLE inf_stderr = INVALID_HANDLE_VALUE;
+ bool redirected = false;
char *w32env;
char *temp;
size_t envlen;
int i;
size_t envsize;
char **env;
-#endif
+#endif /* !__CYGWIN__ */
PROCESS_INFORMATION pi;
BOOL ret;
DWORD flags = 0;
@@ -2183,7 +2483,7 @@ windows_create_inferior (struct target_ops *ops, char *exec_file,
error (_("Error starting executable: %d"), errno);
cygallargs = (wchar_t *) alloca (len * sizeof (wchar_t));
mbstowcs (cygallargs, allargs, len);
-#else
+#else /* !__USEWIDE */
cygallargs = allargs;
#endif
}
@@ -2199,12 +2499,12 @@ windows_create_inferior (struct target_ops *ops, char *exec_file,
+ mbstowcs (NULL, allargs, 0) + 2;
cygallargs = (wchar_t *) alloca (len * sizeof (wchar_t));
swprintf (cygallargs, len, L" -c 'exec %s %s'", exec_file, allargs);
-#else
+#else /* !__USEWIDE */
len = (sizeof (" -c 'exec '") + strlen (exec_file)
+ strlen (allargs) + 2);
cygallargs = (char *) alloca (len);
xsnprintf (cygallargs, len, " -c 'exec %s %s'", exec_file, allargs);
-#endif
+#endif /* __USEWIDE */
toexec = shell;
flags |= DEBUG_PROCESS;
}
@@ -2215,12 +2515,12 @@ windows_create_inferior (struct target_ops *ops, char *exec_file,
wcscpy (args, toexec);
wcscat (args, L" ");
wcscat (args, cygallargs);
-#else
+#else /* !__USEWIDE */
args = (cygwin_buf_t *) alloca (strlen (toexec) + strlen (cygallargs) + 2);
strcpy (args, toexec);
strcat (args, " ");
strcat (args, cygallargs);
-#endif
+#endif /* !__USEWIDE */
#ifdef CW_CVT_ENV_TO_WINENV
/* First try to create a direct Win32 copy of the POSIX environment. */
@@ -2229,7 +2529,7 @@ windows_create_inferior (struct target_ops *ops, char *exec_file,
flags |= CREATE_UNICODE_ENVIRONMENT;
else
/* If that fails, fall back to old method tweaking GDB's environment. */
-#endif
+#endif /* CW_CVT_ENV_TO_WINENV */
{
/* Reset all Win32 environment variables to avoid leftover on next run. */
clear_win32_environment (environ);
@@ -2294,21 +2594,26 @@ windows_create_inferior (struct target_ops *ops, char *exec_file,
close (ostdout);
close (ostderr);
}
-#else
- toexec = exec_file;
- /* Build the command line, a space-separated list of tokens where
- the first token is the name of the module to be executed.
- To avoid ambiguities introduced by spaces in the module name,
- we quote it. */
- args_len = strlen (toexec) + 2 /* quotes */ + strlen (allargs) + 2;
- args = (char *) alloca (args_len);
- xsnprintf (args, args_len, "\"%s\" %s", toexec, allargs);
-
- flags |= DEBUG_ONLY_THIS_PROCESS;
-
- if (!inferior_io_terminal)
- tty = INVALID_HANDLE_VALUE;
- else
+#else /* !__CYGWIN__ */
+ allargs_len = strlen (allargs);
+ allargs_copy = strcpy ((char *) alloca (allargs_len + 1), allargs);
+ if (strpbrk (allargs_copy, "<>") != NULL)
+ {
+ int e = errno;
+ errno = 0;
+ redirected =
+ redirect_inferior_handles (allargs, allargs_copy,
+ &fd_inp, &fd_out, &fd_err);
+ if (errno)
+ warning (_("Error in redirection: %s."), strerror (errno));
+ else
+ errno = e;
+ allargs_len = strlen (allargs_copy);
+ }
+ /* If not all the standard streams are redirected by the command
+ line, use inferior_io_terminal for those which aren't. */
+ if (inferior_io_terminal
+ && !(fd_inp >= 0 && fd_out >= 0 && fd_err >= 0))
{
SECURITY_ATTRIBUTES sa;
sa.nLength = sizeof(sa);
@@ -2319,15 +2624,41 @@ windows_create_inferior (struct target_ops *ops, char *exec_file,
if (tty == INVALID_HANDLE_VALUE)
warning (_("Warning: Failed to open TTY %s, error %#x."),
inferior_io_terminal, (unsigned) GetLastError ());
+ }
+ if (redirected || tty != INVALID_HANDLE_VALUE)
+ {
+ if (fd_inp >= 0)
+ si.hStdInput = (HANDLE) _get_osfhandle (fd_inp);
+ else if (tty != INVALID_HANDLE_VALUE)
+ si.hStdInput = tty;
else
- {
- si.hStdInput = tty;
- si.hStdOutput = tty;
- si.hStdError = tty;
- si.dwFlags |= STARTF_USESTDHANDLES;
- }
+ si.hStdInput = GetStdHandle (STD_INPUT_HANDLE);
+ if (fd_out >= 0)
+ si.hStdOutput = (HANDLE) _get_osfhandle (fd_out);
+ else if (tty != INVALID_HANDLE_VALUE)
+ si.hStdOutput = tty;
+ else
+ si.hStdOutput = GetStdHandle (STD_OUTPUT_HANDLE);
+ if (fd_err >= 0)
+ si.hStdError = (HANDLE) _get_osfhandle (fd_err);
+ else if (tty != INVALID_HANDLE_VALUE)
+ si.hStdError = tty;
+ else
+ si.hStdError = GetStdHandle (STD_ERROR_HANDLE);
+ si.dwFlags |= STARTF_USESTDHANDLES;
}
+ toexec = exec_file;
+ /* Build the command line, a space-separated list of tokens where
+ the first token is the name of the module to be executed.
+ To avoid ambiguities introduced by spaces in the module name,
+ we quote it. */
+ args_len = strlen (toexec) + 2 /* quotes */ + allargs_len + 2;
+ args = (char *) alloca (args_len);
+ xsnprintf (args, args_len, "\"%s\" %s", toexec, allargs_copy);
+
+ flags |= DEBUG_ONLY_THIS_PROCESS;
+
/* CreateProcess takes the environment list as a null terminated set of
strings (i.e. two nulls terminate the list). */
@@ -2366,7 +2697,13 @@ windows_create_inferior (struct target_ops *ops, char *exec_file,
&pi);
if (tty != INVALID_HANDLE_VALUE)
CloseHandle (tty);
-#endif
+ if (fd_inp >= 0)
+ _close (fd_inp);
+ if (fd_out >= 0)
+ _close (fd_out);
+ if (fd_err >= 0)
+ _close (fd_err);
+#endif /* !__CYGWIN__ */
if (!ret)
error (_("Error creating process %s, (error %u)."),