summaryrefslogtreecommitdiff
path: root/compat/mingw.c
diff options
context:
space:
mode:
authorJunio C Hamano <gitster@pobox.com>2019-12-10 21:11:42 (GMT)
committerJunio C Hamano <gitster@pobox.com>2019-12-10 21:11:42 (GMT)
commit55d607d85b4c22fe2091102ed1eb907ea29b956a (patch)
tree15d39f4c879ca2ee09353de0ea98dc86cd298bb7 /compat/mingw.c
parent7c887142621106a303a321b51b1958112ed2bf24 (diff)
parent3ba3720b3f187644ac0186a4637898f8e8f85a91 (diff)
downloadgit-55d607d85b4c22fe2091102ed1eb907ea29b956a.zip
git-55d607d85b4c22fe2091102ed1eb907ea29b956a.tar.gz
git-55d607d85b4c22fe2091102ed1eb907ea29b956a.tar.bz2
Merge branch 'js/mingw-inherit-only-std-handles'
Work around a issue where a FD that is left open when spawning a child process and is kept open in the child can interfere with the operation in the parent process on Windows. * js/mingw-inherit-only-std-handles: mingw: forbid translating ERROR_SUCCESS to an errno value mingw: do set `errno` correctly when trying to restrict handle inheritance mingw: restrict file handle inheritance only on Windows 7 and later mingw: spawned processes need to inherit only standard handles mingw: work around incorrect standard handles mingw: demonstrate that all file handles are inherited by child processes
Diffstat (limited to 'compat/mingw.c')
-rw-r--r--compat/mingw.c145
1 files changed, 134 insertions, 11 deletions
diff --git a/compat/mingw.c b/compat/mingw.c
index ae72c92..c2a4835 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -114,6 +114,7 @@ int err_win_to_posix(DWORD winerr)
case ERROR_SHARING_BUFFER_EXCEEDED: error = ENFILE; break;
case ERROR_SHARING_VIOLATION: error = EACCES; break;
case ERROR_STACK_OVERFLOW: error = ENOMEM; break;
+ case ERROR_SUCCESS: BUG("err_win_to_posix() called without an error!");
case ERROR_SWAPERROR: error = ENOENT; break;
case ERROR_TOO_MANY_MODULES: error = EMFILE; break;
case ERROR_TOO_MANY_OPEN_FILES: error = EMFILE; break;
@@ -212,6 +213,7 @@ enum hide_dotfiles_type {
HIDE_DOTFILES_DOTGITONLY
};
+static int core_restrict_inherited_handles = -1;
static enum hide_dotfiles_type hide_dotfiles = HIDE_DOTFILES_DOTGITONLY;
static char *unset_environment_variables;
@@ -231,6 +233,15 @@ int mingw_core_config(const char *var, const char *value, void *cb)
return 0;
}
+ if (!strcmp(var, "core.restrictinheritedhandles")) {
+ if (value && !strcasecmp(value, "auto"))
+ core_restrict_inherited_handles = -1;
+ else
+ core_restrict_inherited_handles =
+ git_config_bool(var, value);
+ return 0;
+ }
+
return 0;
}
@@ -1436,8 +1447,13 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
const char *dir,
int prepend_cmd, int fhin, int fhout, int fherr)
{
- STARTUPINFOW si;
+ static int restrict_handle_inheritance = -1;
+ STARTUPINFOEXW si;
PROCESS_INFORMATION pi;
+ LPPROC_THREAD_ATTRIBUTE_LIST attr_list = NULL;
+ HANDLE stdhandles[3];
+ DWORD stdhandles_count = 0;
+ SIZE_T size;
struct strbuf args;
wchar_t wcmd[MAX_PATH], wdir[MAX_PATH], *wargs, *wenvblk = NULL;
unsigned flags = CREATE_UNICODE_ENVIRONMENT;
@@ -1447,6 +1463,19 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
is_msys2_sh(cmd ? cmd : *argv) ?
quote_arg_msys2 : quote_arg_msvc;
+ /* Make sure to override previous errors, if any */
+ errno = 0;
+
+ if (restrict_handle_inheritance < 0)
+ restrict_handle_inheritance = core_restrict_inherited_handles;
+ /*
+ * The following code to restrict which handles are inherited seems
+ * to work properly only on Windows 7 and later, so let's disable it
+ * on Windows Vista and 2008.
+ */
+ if (restrict_handle_inheritance < 0)
+ restrict_handle_inheritance = GetVersion() >> 16 >= 7601;
+
do_unset_environment_variables();
/* Determine whether or not we are associated to a console */
@@ -1474,11 +1503,23 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
CloseHandle(cons);
}
memset(&si, 0, sizeof(si));
- si.cb = sizeof(si);
- si.dwFlags = STARTF_USESTDHANDLES;
- si.hStdInput = winansi_get_osfhandle(fhin);
- si.hStdOutput = winansi_get_osfhandle(fhout);
- si.hStdError = winansi_get_osfhandle(fherr);
+ si.StartupInfo.cb = sizeof(si);
+ si.StartupInfo.hStdInput = winansi_get_osfhandle(fhin);
+ si.StartupInfo.hStdOutput = winansi_get_osfhandle(fhout);
+ si.StartupInfo.hStdError = winansi_get_osfhandle(fherr);
+
+ /* The list of handles cannot contain duplicates */
+ if (si.StartupInfo.hStdInput != INVALID_HANDLE_VALUE)
+ stdhandles[stdhandles_count++] = si.StartupInfo.hStdInput;
+ if (si.StartupInfo.hStdOutput != INVALID_HANDLE_VALUE &&
+ si.StartupInfo.hStdOutput != si.StartupInfo.hStdInput)
+ stdhandles[stdhandles_count++] = si.StartupInfo.hStdOutput;
+ if (si.StartupInfo.hStdError != INVALID_HANDLE_VALUE &&
+ si.StartupInfo.hStdError != si.StartupInfo.hStdInput &&
+ si.StartupInfo.hStdError != si.StartupInfo.hStdOutput)
+ stdhandles[stdhandles_count++] = si.StartupInfo.hStdError;
+ if (stdhandles_count)
+ si.StartupInfo.dwFlags |= STARTF_USESTDHANDLES;
if (*argv && !strcmp(cmd, *argv))
wcmd[0] = L'\0';
@@ -1511,16 +1552,98 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
wenvblk = make_environment_block(deltaenv);
memset(&pi, 0, sizeof(pi));
- ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL, TRUE,
- flags, wenvblk, dir ? wdir : NULL, &si, &pi);
+ if (restrict_handle_inheritance && stdhandles_count &&
+ (InitializeProcThreadAttributeList(NULL, 1, 0, &size) ||
+ GetLastError() == ERROR_INSUFFICIENT_BUFFER) &&
+ (attr_list = (LPPROC_THREAD_ATTRIBUTE_LIST)
+ (HeapAlloc(GetProcessHeap(), 0, size))) &&
+ InitializeProcThreadAttributeList(attr_list, 1, 0, &size) &&
+ UpdateProcThreadAttribute(attr_list, 0,
+ PROC_THREAD_ATTRIBUTE_HANDLE_LIST,
+ stdhandles,
+ stdhandles_count * sizeof(HANDLE),
+ NULL, NULL)) {
+ si.lpAttributeList = attr_list;
+ flags |= EXTENDED_STARTUPINFO_PRESENT;
+ }
+
+ ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL,
+ stdhandles_count ? TRUE : FALSE,
+ flags, wenvblk, dir ? wdir : NULL,
+ &si.StartupInfo, &pi);
+
+ /*
+ * On Windows 2008 R2, it seems that specifying certain types of handles
+ * (such as FILE_TYPE_CHAR or FILE_TYPE_PIPE) will always produce an
+ * error. Rather than playing finicky and fragile games, let's just try
+ * to detect this situation and simply try again without restricting any
+ * handle inheritance. This is still better than failing to create
+ * processes.
+ */
+ if (!ret && restrict_handle_inheritance && stdhandles_count) {
+ DWORD err = GetLastError();
+ struct strbuf buf = STRBUF_INIT;
+
+ if (err != ERROR_NO_SYSTEM_RESOURCES &&
+ /*
+ * On Windows 7 and earlier, handles on pipes and character
+ * devices are inherited automatically, and cannot be
+ * specified in the thread handle list. Rather than trying
+ * to catch each and every corner case (and running the
+ * chance of *still* forgetting a few), let's just fall
+ * back to creating the process without trying to limit the
+ * handle inheritance.
+ */
+ !(err == ERROR_INVALID_PARAMETER &&
+ GetVersion() >> 16 < 9200) &&
+ !getenv("SUPPRESS_HANDLE_INHERITANCE_WARNING")) {
+ DWORD fl = 0;
+ int i;
+
+ setenv("SUPPRESS_HANDLE_INHERITANCE_WARNING", "1", 1);
+
+ for (i = 0; i < stdhandles_count; i++) {
+ HANDLE h = stdhandles[i];
+ strbuf_addf(&buf, "handle #%d: %p (type %lx, "
+ "handle info (%d) %lx\n", i, h,
+ GetFileType(h),
+ GetHandleInformation(h, &fl),
+ fl);
+ }
+ strbuf_addstr(&buf, "\nThis is a bug; please report it "
+ "at\nhttps://github.com/git-for-windows/"
+ "git/issues/new\n\n"
+ "To suppress this warning, please set "
+ "the environment variable\n\n"
+ "\tSUPPRESS_HANDLE_INHERITANCE_WARNING=1"
+ "\n");
+ }
+ restrict_handle_inheritance = 0;
+ flags &= ~EXTENDED_STARTUPINFO_PRESENT;
+ ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL,
+ TRUE, flags, wenvblk, dir ? wdir : NULL,
+ &si.StartupInfo, &pi);
+ if (!ret)
+ errno = err_win_to_posix(GetLastError());
+ if (ret && buf.len) {
+ warning("failed to restrict file handles (%ld)\n\n%s",
+ err, buf.buf);
+ }
+ strbuf_release(&buf);
+ } else if (!ret)
+ errno = err_win_to_posix(GetLastError());
+
+ if (si.lpAttributeList)
+ DeleteProcThreadAttributeList(si.lpAttributeList);
+ if (attr_list)
+ HeapFree(GetProcessHeap(), 0, attr_list);
free(wenvblk);
free(wargs);
- if (!ret) {
- errno = ENOENT;
+ if (!ret)
return -1;
- }
+
CloseHandle(pi.hThread);
/*