[compiler-rt] r288624 - [sanitizer] Make atos stdin a non-tty pipe to make sure it's not stuck waiting for user input
Kuba Mracek via llvm-commits
llvm-commits at lists.llvm.org
Sun Dec 4 13:52:22 PST 2016
Author: kuba.brecka
Date: Sun Dec 4 15:52:21 2016
New Revision: 288624
URL: http://llvm.org/viewvc/llvm-project?rev=288624&view=rev
Log:
[sanitizer] Make atos stdin a non-tty pipe to make sure it's not stuck waiting for user input
On macOS, we often symbolicate using atos (when llvm-symbolizer is not found). The current way we invoke atos involves creating a pseudo-terminal to make sure atos doesn't buffer its output. This however also makes atos think that it's stdin is interactive and in some error situations it will ask the user to enter some input instead of just printing out an error message. For example, when Developer Mode isn't enabled on a machine, atos cannot examine processes, and it will ask the user to enter an administrator's password, which will make the sanitized process get stuck. This patch only connects the pseudo-terminal to the stdout of atos, and uses a regular pipe as its stdin.
Differential Revision: https://reviews.llvm.org/D27239
Modified:
compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc?rev=288624&r1=288623&r2=288624&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc Sun Dec 4 15:52:21 2016
@@ -101,6 +101,46 @@ const char *DemangleSwiftAndCXX(const ch
return DemangleCXXABI(name);
}
+static bool CreateTwoHighNumberedPipes(int *infd_, int *outfd_) {
+ int *infd = NULL;
+ int *outfd = NULL;
+ // The client program may close its stdin and/or stdout and/or stderr
+ // thus allowing socketpair to reuse file descriptors 0, 1 or 2.
+ // In this case the communication between the forked processes may be
+ // broken if either the parent or the child tries to close or duplicate
+ // these descriptors. The loop below produces two pairs of file
+ // descriptors, each greater than 2 (stderr).
+ int sock_pair[5][2];
+ for (int i = 0; i < 5; i++) {
+ if (pipe(sock_pair[i]) == -1) {
+ for (int j = 0; j < i; j++) {
+ internal_close(sock_pair[j][0]);
+ internal_close(sock_pair[j][1]);
+ }
+ return false;
+ } else if (sock_pair[i][0] > 2 && sock_pair[i][1] > 2) {
+ if (infd == NULL) {
+ infd = sock_pair[i];
+ } else {
+ outfd = sock_pair[i];
+ for (int j = 0; j < i; j++) {
+ if (sock_pair[j] == infd) continue;
+ internal_close(sock_pair[j][0]);
+ internal_close(sock_pair[j][1]);
+ }
+ break;
+ }
+ }
+ }
+ CHECK(infd);
+ CHECK(outfd);
+ infd_[0] = infd[0];
+ infd_[1] = infd[1];
+ outfd_[0] = outfd[0];
+ outfd_[1] = outfd[1];
+ return true;
+}
+
bool SymbolizerProcess::StartSymbolizerSubprocess() {
if (!FileExists(path_)) {
if (!reported_invalid_path_) {
@@ -110,7 +150,16 @@ bool SymbolizerProcess::StartSymbolizerS
return false;
}
- int pid;
+ int pid = -1;
+
+ int infd[2] = {};
+ int outfd[2] = {};
+ if (!CreateTwoHighNumberedPipes(infd, outfd)) {
+ Report("WARNING: Can't create a socket pair to start "
+ "external symbolizer (errno: %d)\n", errno);
+ return false;
+ }
+
if (use_forkpty_) {
#if SANITIZER_MAC
fd_t fd = kInvalidFd;
@@ -121,6 +170,10 @@ bool SymbolizerProcess::StartSymbolizerS
int saved_stderr = dup(STDERR_FILENO);
CHECK_GE(saved_stderr, 0);
+ // We only need one pipe, for stdin of the child.
+ close(outfd[0]);
+ close(outfd[1]);
+
// Use forkpty to disable buffering in the new terminal.
pid = internal_forkpty(&fd);
if (pid == -1) {
@@ -131,6 +184,13 @@ bool SymbolizerProcess::StartSymbolizerS
} else if (pid == 0) {
// Child subprocess.
+ // infd[0] is the child's reading end.
+ close(infd[1]);
+
+ // Set up stdin to read from the pipe.
+ CHECK_GE(dup2(infd[0], STDIN_FILENO), 0);
+ close(infd[0]);
+
// Restore stderr.
CHECK_GE(dup2(saved_stderr, STDERR_FILENO), 0);
close(saved_stderr);
@@ -141,8 +201,12 @@ bool SymbolizerProcess::StartSymbolizerS
internal__exit(1);
}
+ // Input for the child, infd[1] is our writing end.
+ output_fd_ = infd[1];
+ close(infd[0]);
+
// Continue execution in parent process.
- input_fd_ = output_fd_ = fd;
+ input_fd_ = fd;
close(saved_stderr);
@@ -156,41 +220,6 @@ bool SymbolizerProcess::StartSymbolizerS
UNIMPLEMENTED();
#endif // SANITIZER_MAC
} else {
- int *infd = NULL;
- int *outfd = NULL;
- // The client program may close its stdin and/or stdout and/or stderr
- // thus allowing socketpair to reuse file descriptors 0, 1 or 2.
- // In this case the communication between the forked processes may be
- // broken if either the parent or the child tries to close or duplicate
- // these descriptors. The loop below produces two pairs of file
- // descriptors, each greater than 2 (stderr).
- int sock_pair[5][2];
- for (int i = 0; i < 5; i++) {
- if (pipe(sock_pair[i]) == -1) {
- for (int j = 0; j < i; j++) {
- internal_close(sock_pair[j][0]);
- internal_close(sock_pair[j][1]);
- }
- Report("WARNING: Can't create a socket pair to start "
- "external symbolizer (errno: %d)\n", errno);
- return false;
- } else if (sock_pair[i][0] > 2 && sock_pair[i][1] > 2) {
- if (infd == NULL) {
- infd = sock_pair[i];
- } else {
- outfd = sock_pair[i];
- for (int j = 0; j < i; j++) {
- if (sock_pair[j] == infd) continue;
- internal_close(sock_pair[j][0]);
- internal_close(sock_pair[j][1]);
- }
- break;
- }
- }
- }
- CHECK(infd);
- CHECK(outfd);
-
const char *argv[kArgVMax];
GetArgV(path_, argv);
pid = StartSubprocess(path_, argv, /* stdin */ outfd[0],
@@ -205,6 +234,8 @@ bool SymbolizerProcess::StartSymbolizerS
output_fd_ = outfd[1];
}
+ CHECK_GT(pid, 0);
+
// Check that symbolizer subprocess started successfully.
SleepForMillis(kSymbolizerStartupTimeMillis);
if (!IsProcessRunning(pid)) {
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