diff options
Diffstat (limited to 'lib/windows-spawn.c')
| -rw-r--r-- | lib/windows-spawn.c | 727 |
1 files changed, 727 insertions, 0 deletions
diff --git a/lib/windows-spawn.c b/lib/windows-spawn.c new file mode 100644 index 0000000..a781090 --- /dev/null +++ b/lib/windows-spawn.c @@ -0,0 +1,727 @@ +/* Auxiliary functions for the creation of subprocesses. Native Windows API. + Copyright (C) 2001, 2003-2020 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2003. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> + +/* Specification. */ +#include "windows-spawn.h" + +/* Get declarations of the native Windows API functions. */ +#define WIN32_LEAN_AND_MEAN +#include <windows.h> + +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> + +/* Get _get_osfhandle(). */ +#if GNULIB_MSVC_NOTHROW +# include "msvc-nothrow.h" +#else +# include <io.h> +#endif +#include <process.h> + +#include "findprog.h" + +/* Don't assume that UNICODE is not defined. */ +#undef STARTUPINFO +#define STARTUPINFO STARTUPINFOA +#undef CreateProcess +#define CreateProcess CreateProcessA + +#define SHELL_SPECIAL_CHARS "\"\\ \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037*?" +#define SHELL_SPACE_CHARS " \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037" + +/* Returns the length of a quoted argument string. */ +static size_t +quoted_arg_length (const char *string) +{ + bool quote_around = (strpbrk (string, SHELL_SPACE_CHARS) != NULL); + size_t length; + unsigned int backslashes; + const char *s; + + length = 0; + backslashes = 0; + if (quote_around) + length++; + for (s = string; *s != '\0'; s++) + { + char c = *s; + if (c == '"') + length += backslashes + 1; + length++; + if (c == '\\') + backslashes++; + else + backslashes = 0; + } + if (quote_around) + length += backslashes + 1; + + return length; +} + +/* Produces a quoted argument string. + Stores exactly quoted_arg_length (STRING) + 1 bytes, including the final + NUL byte, at MEM. + Returns a pointer past the stored quoted argument string. */ +static char * +quoted_arg_string (const char *string, char *mem) +{ + bool quote_around = (strpbrk (string, SHELL_SPACE_CHARS) != NULL); + char *p; + unsigned int backslashes; + const char *s; + + p = mem; + backslashes = 0; + if (quote_around) + *p++ = '"'; + for (s = string; *s != '\0'; s++) + { + char c = *s; + if (c == '"') + { + unsigned int j; + for (j = backslashes + 1; j > 0; j--) + *p++ = '\\'; + } + *p++ = c; + if (c == '\\') + backslashes++; + else + backslashes = 0; + } + if (quote_around) + { + unsigned int j; + for (j = backslashes; j > 0; j--) + *p++ = '\\'; + *p++ = '"'; + } + *p++ = '\0'; + + return p; +} + +const char ** +prepare_spawn (const char * const *argv, char **mem_to_free) +{ + size_t argc; + const char **new_argv; + size_t i; + + /* Count number of arguments. */ + for (argc = 0; argv[argc] != NULL; argc++) + ; + + /* Allocate new argument vector. */ + new_argv = (const char **) malloc ((1 + argc + 1) * sizeof (const char *)); + + /* Add an element upfront that can be used when argv[0] turns out to be a + script, not a program. + On Unix, this would be "/bin/sh". On native Windows, "sh" is actually + "sh.exe". We have to omit the directory part and rely on the search in + PATH, because the mingw "mount points" are not visible inside Windows + CreateProcess(). */ + new_argv[0] = "sh.exe"; + + /* Put quoted arguments into the new argument vector. */ + size_t needed_size = 0; + for (i = 0; i < argc; i++) + { + const char *string = argv[i]; + size_t length; + + if (string[0] == '\0') + length = strlen ("\"\""); + else if (strpbrk (string, SHELL_SPECIAL_CHARS) != NULL) + length = quoted_arg_length (string); + else + length = strlen (string); + needed_size += length + 1; + } + + char *mem; + if (needed_size == 0) + mem = NULL; + else + { + mem = (char *) malloc (needed_size); + if (mem == NULL) + { + /* Memory allocation failure. */ + free (new_argv); + errno = ENOMEM; + return NULL; + } + } + *mem_to_free = mem; + + for (i = 0; i < argc; i++) + { + const char *string = argv[i]; + + new_argv[1 + i] = mem; + if (string[0] == '\0') + { + size_t length = strlen ("\"\""); + memcpy (mem, "\"\"", length + 1); + mem += length + 1; + } + else if (strpbrk (string, SHELL_SPECIAL_CHARS) != NULL) + { + mem = quoted_arg_string (string, mem); + } + else + { + size_t length = strlen (string); + memcpy (mem, string, length + 1); + mem += length + 1; + } + } + new_argv[1 + argc] = NULL; + + return new_argv; +} + +char * +compose_command (const char * const *argv) +{ + /* Just concatenate the argv[] strings, separated by spaces. */ + char *command; + + /* Determine the size of the needed block of memory. */ + size_t total_size = 0; + const char * const *ap; + const char *p; + for (ap = argv; (p = *ap) != NULL; ap++) + total_size += strlen (p) + 1; + size_t command_size = (total_size > 0 ? total_size : 1); + + /* Allocate the block of memory. */ + command = (char *) malloc (command_size); + if (command == NULL) + { + errno = ENOMEM; + return NULL; + } + + /* Fill it. */ + if (total_size > 0) + { + char *cp = command; + for (ap = argv; (p = *ap) != NULL; ap++) + { + size_t size = strlen (p) + 1; + memcpy (cp, p, size - 1); + cp += size; + cp[-1] = ' '; + } + cp[-1] = '\0'; + } + else + *command = '\0'; + + return command; +} + +char * +compose_envblock (const char * const *envp) +{ + /* This is a bit hairy, because we don't have a lock that would prevent other + threads from making modifications in ENVP. So, just make sure we don't + crash; but if other threads are making modifications, part of the result + may be wrong. */ + retry: + { + /* Guess the size of the needed block of memory. + The guess will be exact if other threads don't make modifications. */ + size_t total_size = 0; + const char * const *ep; + const char *p; + for (ep = envp; (p = *ep) != NULL; ep++) + total_size += strlen (p) + 1; + size_t envblock_size = total_size; + + /* Allocate the block of memory. */ + char *envblock = (char *) malloc (envblock_size + 1); + if (envblock == NULL) + { + errno = ENOMEM; + return NULL; + } + size_t envblock_used = 0; + for (ep = envp; (p = *ep) != NULL; ep++) + { + size_t size = strlen (p) + 1; + if (envblock_used + size > envblock_size) + { + /* Other threads did modifications. Need more memory. */ + envblock_size += envblock_size / 2; + if (envblock_used + size > envblock_size) + envblock_size = envblock_used + size; + + char *new_envblock = (char *) realloc (envblock, envblock_size + 1); + if (new_envblock == NULL) + { + free (envblock); + errno = ENOMEM; + return NULL; + } + envblock = new_envblock; + } + memcpy (envblock + envblock_used, p, size); + envblock_used += size; + if (envblock[envblock_used - 1] != '\0') + { + /* Other threads did modifications. Restart. */ + free (envblock); + goto retry; + } + } + envblock[envblock_used] = '\0'; + return envblock; + } +} + +int +init_inheritable_handles (struct inheritable_handles *inh_handles, + bool duplicate) +{ + /* Determine the minimal count of handles we need to care about. */ + size_t handles_count; + { + /* _getmaxstdio + <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/getmaxstdio> + Default value is 512. */ + unsigned int fdmax = _getmaxstdio (); + if (fdmax < 3) + fdmax = 3; + for (; fdmax > 3; fdmax--) + { + unsigned int fd = fdmax - 1; + /* _get_osfhandle + <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/get-osfhandle> */ + HANDLE handle = (HANDLE) _get_osfhandle (fd); + if (handle != INVALID_HANDLE_VALUE) + { + DWORD hflags; + /* GetHandleInformation + <https://docs.microsoft.com/en-us/windows/win32/api/handleapi/nf-handleapi-gethandleinformation> */ + if (GetHandleInformation (handle, &hflags)) + { + if ((hflags & HANDLE_FLAG_INHERIT) != 0) + /* fd denotes an inheritable descriptor. */ + break; + } + } + } + handles_count = fdmax; + } + /* Note: handles_count >= 3. */ + + /* Allocate the arrays. */ + size_t handles_allocated = handles_count; + HANDLE *handles_array = + (HANDLE *) malloc (handles_allocated * sizeof (HANDLE)); + if (handles_array == NULL) + { + errno = ENOMEM; + return -1; + } + unsigned char *flags_array = + (unsigned char *) malloc (handles_allocated * sizeof (unsigned char)); + if (flags_array == NULL) + { + free (handles_array); + errno = ENOMEM; + return -1; + } + + /* Fill in the two arrays. */ + { + HANDLE curr_process = (duplicate ? GetCurrentProcess () : INVALID_HANDLE_VALUE); + unsigned int fd; + for (fd = 0; fd < handles_count; fd++) + { + handles_array[fd] = INVALID_HANDLE_VALUE; + /* _get_osfhandle + <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/get-osfhandle> */ + HANDLE handle = (HANDLE) _get_osfhandle (fd); + if (handle != INVALID_HANDLE_VALUE) + { + DWORD hflags; + /* GetHandleInformation + <https://docs.microsoft.com/en-us/windows/win32/api/handleapi/nf-handleapi-gethandleinformation> */ + if (GetHandleInformation (handle, &hflags)) + { + if ((hflags & HANDLE_FLAG_INHERIT) != 0) + { + /* fd denotes an inheritable descriptor. */ + if (duplicate) + { + if (!DuplicateHandle (curr_process, handle, + curr_process, &handles_array[fd], + 0, TRUE, DUPLICATE_SAME_ACCESS)) + { + unsigned int i; + for (i = 0; i < fd; i++) + if (handles_array[i] != INVALID_HANDLE_VALUE) + CloseHandle (handles_array[i]); + free (flags_array); + free (handles_array); + errno = EBADF; /* arbitrary */ + return -1; + } + } + else + handles_array[fd] = handle; + + flags_array[fd] = 0; + } + } + } + } + } + + /* Return the result. */ + inh_handles->count = handles_count; + inh_handles->allocated = handles_allocated; + inh_handles->handles = handles_array; + inh_handles->flags = flags_array; + return 0; +} + +int +compose_handles_block (const struct inheritable_handles *inh_handles, + STARTUPINFO *sinfo) +{ + /* STARTUPINFO + <https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/ns-processthreadsapi-startupinfoa> */ + sinfo->dwFlags = STARTF_USESTDHANDLES; + sinfo->hStdInput = inh_handles->handles[0]; + sinfo->hStdOutput = inh_handles->handles[1]; + sinfo->hStdError = inh_handles->handles[2]; + + /* On newer versions of Windows, more file descriptors / handles than the + first three can be passed. + The format is as follows: Let N be an exclusive upper bound for the file + descriptors to be passed. Two arrays are constructed in memory: + - flags[0..N-1], of element type 'unsigned char', + - handles[0..N-1], of element type 'HANDLE' or 'intptr_t'. + For used entries, handles[i] is the handle, and flags[i] is a set of flags, + a combination of: + 1 for open file descriptors, + 64 for handles of type FILE_TYPE_CHAR, + 8 for handles of type FILE_TYPE_PIPE, + 32 for O_APPEND. + For unused entries - this may include any of the first three, since they + are already passed above -, handles[i] is INVALID_HANDLE_VALUE and flags[i] + is zero. + lpReserved2 now is a pointer to the concatenation (without padding) of: + - an 'unsigned int' whose value is N, + - the contents of the flags[0..N-1] array, + - the contents of the handles[0..N-1] array. + cbReserved2 is the size (in bytes) of the object at lpReserved2. */ + + size_t handles_count = inh_handles->count; + + sinfo->cbReserved2 = + sizeof (unsigned int) + + handles_count * sizeof (unsigned char) + + handles_count * sizeof (HANDLE); + /* Add some padding, so that we can work with a properly aligned HANDLE + array. */ + char *hblock = (char *) malloc (sinfo->cbReserved2 + (sizeof (HANDLE) - 1)); + if (hblock == NULL) + { + errno = ENOMEM; + return -1; + } + unsigned char *flags = (unsigned char *) (hblock + sizeof (unsigned int)); + char *handles = (char *) (flags + handles_count); + HANDLE *handles_aligned = + (HANDLE *) (((uintptr_t) handles + (sizeof (HANDLE) - 1)) + & - (uintptr_t) sizeof (HANDLE)); + + * (unsigned int *) hblock = handles_count; + { + unsigned int fd; + for (fd = 0; fd < handles_count; fd++) + { + handles_aligned[fd] = INVALID_HANDLE_VALUE; + flags[fd] = 0; + + HANDLE handle = inh_handles->handles[fd]; + if (handle != INVALID_HANDLE_VALUE + /* The first three are possibly already passed above. + But they need to passed here as well, if they have some flags. */ + && (fd >= 3 || inh_handles->flags[fd] != 0)) + { + DWORD hflags; + /* GetHandleInformation + <https://docs.microsoft.com/en-us/windows/win32/api/handleapi/nf-handleapi-gethandleinformation> */ + if (GetHandleInformation (handle, &hflags)) + { + if ((hflags & HANDLE_FLAG_INHERIT) != 0) + { + /* fd denotes an inheritable descriptor. */ + handles_aligned[fd] = handle; + /* On Microsoft Windows, it would be sufficient to set + flags[fd] = 1. But on ReactOS or Wine, adding the bit + that indicates the handle type may be necessary. So, + just do it everywhere. */ + flags[fd] = 1 | inh_handles->flags[fd]; + switch (GetFileType (handle)) + { + case FILE_TYPE_CHAR: + flags[fd] |= 64; + break; + case FILE_TYPE_PIPE: + flags[fd] |= 8; + break; + default: + break; + } + } + else + /* We shouldn't have any non-inheritable handles in + inh_handles->handles. */ + abort (); + } + } + } + } + if (handles != (char *) handles_aligned) + memmove (handles, (char *) handles_aligned, handles_count * sizeof (HANDLE)); + + sinfo->lpReserved2 = (BYTE *) hblock; + + return 0; +} + +void +free_inheritable_handles (struct inheritable_handles *inh_handles) +{ + free (inh_handles->flags); + free (inh_handles->handles); +} + +int +convert_CreateProcess_error (DWORD error) +{ + /* Some of these errors probably cannot happen. But who knows... */ + switch (error) + { + case ERROR_FILE_NOT_FOUND: + case ERROR_PATH_NOT_FOUND: + case ERROR_BAD_PATHNAME: + case ERROR_BAD_NET_NAME: + case ERROR_INVALID_NAME: + case ERROR_DIRECTORY: + return ENOENT; + break; + + case ERROR_ACCESS_DENIED: + case ERROR_SHARING_VIOLATION: + return EACCES; + break; + + case ERROR_OUTOFMEMORY: + return ENOMEM; + break; + + case ERROR_BUFFER_OVERFLOW: + case ERROR_FILENAME_EXCED_RANGE: + return ENAMETOOLONG; + break; + + case ERROR_BAD_FORMAT: + case ERROR_BAD_EXE_FORMAT: + return ENOEXEC; + break; + + default: + return EINVAL; + break; + } +} + +intptr_t +spawnpvech (int mode, + const char *progname, const char * const *argv, + const char * const *envp, + const char *currdir, + HANDLE stdin_handle, HANDLE stdout_handle, HANDLE stderr_handle) +{ + /* Validate the arguments. */ + if (!(mode == P_WAIT + || mode == P_NOWAIT + || mode == P_DETACH + || mode == P_OVERLAY) + || progname == NULL || argv == NULL) + { + errno = EINVAL; + return -1; + } + + /* Implement the 'p' letter: search for PROGNAME in getenv ("PATH"). */ + const char *resolved_progname = + find_in_given_path (progname, getenv ("PATH"), NULL, false); + if (resolved_progname == NULL) + return -1; + + /* Compose the command. */ + char *command = compose_command (argv); + if (command == NULL) + goto out_of_memory_1; + + /* Copy *ENVP into a contiguous block of memory. */ + char *envblock; + if (envp == NULL) + envblock = NULL; + else + { + envblock = compose_envblock (envp); + if (envblock == NULL) + goto out_of_memory_2; + } + + /* Collect the inheritable handles. */ + struct inheritable_handles inh_handles; + if (init_inheritable_handles (&inh_handles, false) < 0) + { + int saved_errno = errno; + if (envblock != NULL) + free (envblock); + free (command); + if (resolved_progname != progname) + free ((char *) resolved_progname); + errno = saved_errno; + return -1; + } + inh_handles.handles[0] = stdin_handle; inh_handles.flags[0] = 0; + inh_handles.handles[1] = stdout_handle; inh_handles.flags[1] = 0; + inh_handles.handles[2] = stderr_handle; inh_handles.flags[2] = 0; + + /* CreateProcess + <https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessa> */ + /* <https://docs.microsoft.com/en-us/windows/win32/procthread/process-creation-flags> */ + DWORD process_creation_flags = (mode == P_DETACH ? DETACHED_PROCESS : 0); + /* STARTUPINFO + <https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/ns-processthreadsapi-startupinfoa> */ + STARTUPINFO sinfo; + sinfo.cb = sizeof (STARTUPINFO); + sinfo.lpReserved = NULL; + sinfo.lpDesktop = NULL; + sinfo.lpTitle = NULL; + if (compose_handles_block (&inh_handles, &sinfo) < 0) + { + int saved_errno = errno; + free_inheritable_handles (&inh_handles); + if (envblock != NULL) + free (envblock); + free (command); + if (resolved_progname != progname) + free ((char *) resolved_progname); + errno = saved_errno; + return -1; + } + + PROCESS_INFORMATION pinfo; + if (!CreateProcess (resolved_progname, command, NULL, NULL, TRUE, + process_creation_flags, envblock, currdir, &sinfo, + &pinfo)) + { + DWORD error = GetLastError (); + + free (sinfo.lpReserved2); + free_inheritable_handles (&inh_handles); + if (envblock != NULL) + free (envblock); + free (command); + if (resolved_progname != progname) + free ((char *) resolved_progname); + + errno = convert_CreateProcess_error (error); + return -1; + } + + if (pinfo.hThread) + CloseHandle (pinfo.hThread); + free (sinfo.lpReserved2); + free_inheritable_handles (&inh_handles); + if (envblock != NULL) + free (envblock); + free (command); + if (resolved_progname != progname) + free ((char *) resolved_progname); + + switch (mode) + { + case P_WAIT: + { + /* Wait until it terminates. Then get its exit status code. */ + switch (WaitForSingleObject (pinfo.hProcess, INFINITE)) + { + case WAIT_OBJECT_0: + break; + case WAIT_FAILED: + errno = ECHILD; + return -1; + default: + abort (); + } + + DWORD exit_code; + if (!GetExitCodeProcess (pinfo.hProcess, &exit_code)) + { + errno = ECHILD; + return -1; + } + CloseHandle (pinfo.hProcess); + return exit_code; + } + + case P_NOWAIT: + /* Return pinfo.hProcess, not pinfo.dwProcessId. */ + return (intptr_t) pinfo.hProcess; + + case P_DETACH: + case P_OVERLAY: + CloseHandle (pinfo.hProcess); + return 0; + + default: + /* Already checked above. */ + abort (); + } + + /*NOTREACHED*/ + out_of_memory_2: + free (command); + out_of_memory_1: + if (resolved_progname != progname) + free ((char *) resolved_progname); + errno = ENOMEM; + return -1; +} |