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[tor-commits] [tor/master] Implement "TOR_PT_EXIT_ON_STDIN_CLOSE".
commit fda61e030e12cbd66a2be9905e6855ec6c6a3c63
Author: Yawning Angel <yawning@xxxxxxxxxxxxxxx>
Date: Thu Mar 26 12:55:12 2015 +0000
Implement "TOR_PT_EXIT_ON_STDIN_CLOSE".
Background processes spawned by Tor now will have a valid stdin.
Pluggable transports can detect this behavior with the aformentioned
enviornment variable, and exit if stdin ever gets closed.
---
changes/feature15435 | 5 +++
src/common/util.c | 81 +++++++++++++++++++++++++++++++++++++--------
src/common/util.h | 3 ++
src/or/transports.c | 5 +++
src/test/test_util_slow.c | 2 ++
5 files changed, 82 insertions(+), 14 deletions(-)
diff --git a/changes/feature15435 b/changes/feature15435
new file mode 100644
index 0000000..afe3603
--- /dev/null
+++ b/changes/feature15435
@@ -0,0 +1,5 @@
+ o Minor features (pluggable Transports):
+ - When launching managed pluggable transports, setup a valid open stdin
+ in the child process that can be used to detect if tor has terminated.
+ The "TOR_PT_EXIT_ON_STDIN_CLOSE" enviornment variable can be used by
+ implementations to detect this new behavior. Resolves ticket 15435.
diff --git a/src/common/util.c b/src/common/util.c
index 2c3a1a1..7096e24 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -3939,9 +3939,11 @@ process_handle_new(void)
process_handle_t *out = tor_malloc_zero(sizeof(process_handle_t));
#ifdef _WIN32
+ out->stdin_pipe = INVALID_HANDLE_VALUE;
out->stdout_pipe = INVALID_HANDLE_VALUE;
out->stderr_pipe = INVALID_HANDLE_VALUE;
#else
+ out->stdin_pipe = -1;
out->stdout_pipe = -1;
out->stderr_pipe = -1;
#endif
@@ -3981,7 +3983,7 @@ process_handle_waitpid_cb(int status, void *arg)
#define CHILD_STATE_FORK 3
#define CHILD_STATE_DUPOUT 4
#define CHILD_STATE_DUPERR 5
-#define CHILD_STATE_REDIRECT 6
+#define CHILD_STATE_DUPIN 6
#define CHILD_STATE_CLOSEFD 7
#define CHILD_STATE_EXEC 8
#define CHILD_STATE_FAILEXEC 9
@@ -4015,6 +4017,8 @@ tor_spawn_background(const char *const filename, const char **argv,
HANDLE stdout_pipe_write = NULL;
HANDLE stderr_pipe_read = NULL;
HANDLE stderr_pipe_write = NULL;
+ HANDLE stdin_pipe_read = NULL;
+ HANDLE stdin_pipe_write = NULL;
process_handle_t *process_handle;
int status;
@@ -4060,6 +4064,20 @@ tor_spawn_background(const char *const filename, const char **argv,
return status;
}
+ /* Set up pipe for stdin */
+ if (!CreatePipe(&stdin_pipe_read, &stdin_pipe_write, &saAttr, 0)) {
+ log_warn(LD_GENERAL,
+ "Failed to create pipe for stdin communication with child process: %s",
+ format_win32_error(GetLastError()));
+ return status;
+ }
+ if (!SetHandleInformation(stderr_pipe_write, HANDLE_FLAG_INHERIT, 0)) {
+ log_warn(LD_GENERAL,
+ "Failed to configure pipe for stdin communication with child "
+ "process: %s", format_win32_error(GetLastError()));
+ return status;
+ }
+
/* Create the child process */
/* Windows expects argv to be a whitespace delimited string, so join argv up
@@ -4074,7 +4092,7 @@ tor_spawn_background(const char *const filename, const char **argv,
siStartInfo.cb = sizeof(STARTUPINFO);
siStartInfo.hStdError = stderr_pipe_write;
siStartInfo.hStdOutput = stdout_pipe_write;
- siStartInfo.hStdInput = NULL;
+ siStartInfo.hStdInput = stdin_pipe_read;
siStartInfo.dwFlags |= STARTF_USESTDHANDLES;
/* Create the child process */
@@ -4104,6 +4122,7 @@ tor_spawn_background(const char *const filename, const char **argv,
/* TODO: Close hProcess and hThread in process_handle->pid? */
process_handle->stdout_pipe = stdout_pipe_read;
process_handle->stderr_pipe = stderr_pipe_read;
+ process_handle->stdin_pipe = stdin_pipe_write;
status = process_handle->status = PROCESS_STATUS_RUNNING;
}
@@ -4114,6 +4133,7 @@ tor_spawn_background(const char *const filename, const char **argv,
pid_t pid;
int stdout_pipe[2];
int stderr_pipe[2];
+ int stdin_pipe[2];
int fd, retval;
ssize_t nbytes;
process_handle_t *process_handle;
@@ -4138,7 +4158,7 @@ tor_spawn_background(const char *const filename, const char **argv,
child_state = CHILD_STATE_PIPE;
- /* Set up pipe for redirecting stdout and stderr of child */
+ /* Set up pipe for redirecting stdout, stderr, and stdin of child */
retval = pipe(stdout_pipe);
if (-1 == retval) {
log_warn(LD_GENERAL,
@@ -4159,6 +4179,20 @@ tor_spawn_background(const char *const filename, const char **argv,
return status;
}
+ retval = pipe(stdin_pipe);
+ if (-1 == retval) {
+ log_warn(LD_GENERAL,
+ "Failed to set up pipe for stdin communication with child process: %s",
+ strerror(errno));
+
+ close(stdout_pipe[0]);
+ close(stdout_pipe[1]);
+ close(stderr_pipe[0]);
+ close(stderr_pipe[1]);
+
+ return status;
+ }
+
child_state = CHILD_STATE_MAXFD;
#ifdef _SC_OPEN_MAX
@@ -4194,13 +4228,11 @@ tor_spawn_background(const char *const filename, const char **argv,
if (-1 == retval)
goto error;
- child_state = CHILD_STATE_REDIRECT;
+ child_state = CHILD_STATE_DUPIN;
- /* Link stdin to /dev/null */
- fd = open("/dev/null", O_RDONLY); /* NOT cloexec, obviously. */
- if (fd != -1)
- dup2(fd, STDIN_FILENO);
- else
+ /* Link child stdin to the read end of the pipe */
+ retval = dup2(stdin_pipe[0], STDIN_FILENO);
+ if (-1 == retval)
goto error;
child_state = CHILD_STATE_CLOSEFD;
@@ -4209,7 +4241,8 @@ tor_spawn_background(const char *const filename, const char **argv,
close(stderr_pipe[1]);
close(stdout_pipe[0]);
close(stdout_pipe[1]);
- close(fd);
+ close(stdin_pipe[0]);
+ close(stdin_pipe[1]);
/* Close all other fds, including the read end of the pipe */
/* XXX: We should now be doing enough FD_CLOEXEC setting to make
@@ -4259,6 +4292,8 @@ tor_spawn_background(const char *const filename, const char **argv,
if (-1 == pid) {
log_warn(LD_GENERAL, "Failed to fork child process: %s", strerror(errno));
+ close(stdin_pipe[0]);
+ close(stdin_pipe[1]);
close(stdout_pipe[0]);
close(stdout_pipe[1]);
close(stderr_pipe[0]);
@@ -4295,16 +4330,28 @@ tor_spawn_background(const char *const filename, const char **argv,
strerror(errno));
}
+ /* Return write end of the stdin pipe to caller, and close the read end */
+ process_handle->stdin_pipe = stdin_pipe[1];
+ retval = close(stdin_pipe[0]);
+
+ if (-1 == retval) {
+ log_warn(LD_GENERAL,
+ "Failed to close read end of stdin pipe in parent process: %s",
+ strerror(errno));
+ }
+
status = process_handle->status = PROCESS_STATUS_RUNNING;
- /* Set stdout/stderr pipes to be non-blocking */
+ /* Set stdin/stdout/stderr pipes to be non-blocking */
if (fcntl(process_handle->stdout_pipe, F_SETFL, O_NONBLOCK) < 0 ||
- fcntl(process_handle->stderr_pipe, F_SETFL, O_NONBLOCK) < 0) {
- log_warn(LD_GENERAL, "Failed to set stderror/stdout pipes nonblocking "
- "in parent process: %s", strerror(errno));
+ fcntl(process_handle->stderr_pipe, F_SETFL, O_NONBLOCK) < 0 ||
+ fcntl(process_handle->stdin_pipe, F_SETFL, O_NONBLOCK) < 0) {
+ log_warn(LD_GENERAL, "Failed to set stderror/stdout/stdin pipes "
+ "nonblocking in parent process: %s", strerror(errno));
}
/* Open the buffered IO streams */
process_handle->stdout_handle = fdopen(process_handle->stdout_pipe, "r");
process_handle->stderr_handle = fdopen(process_handle->stderr_pipe, "r");
+ process_handle->stdin_handle = fdopen(process_handle->stdin_pipe, "r");
*process_handle_out = process_handle;
return process_handle->status;
@@ -4347,6 +4394,9 @@ tor_process_handle_destroy,(process_handle_t *process_handle,
if (process_handle->stderr_pipe)
CloseHandle(process_handle->stderr_pipe);
+
+ if (process_handle->stdin_pipe)
+ CloseHandle(process_handle->stdin_pipe);
#else
if (process_handle->stdout_handle)
fclose(process_handle->stdout_handle);
@@ -4354,6 +4404,9 @@ tor_process_handle_destroy,(process_handle_t *process_handle,
if (process_handle->stderr_handle)
fclose(process_handle->stderr_handle);
+ if (process_handle->stdin_handle)
+ fclose(process_handle->stdin_handle);
+
clear_waitpid_callback(process_handle->waitpid_cb);
#endif
diff --git a/src/common/util.h b/src/common/util.h
index 3584a87..21ac5b3 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -474,12 +474,15 @@ struct process_handle_t {
/** One of the PROCESS_STATUS_* values */
int status;
#ifdef _WIN32
+ HANDLE stdin_pipe;
HANDLE stdout_pipe;
HANDLE stderr_pipe;
PROCESS_INFORMATION pid;
#else
+ int stdin_pipe;
int stdout_pipe;
int stderr_pipe;
+ FILE *stdin_handle;
FILE *stdout_handle;
FILE *stderr_handle;
pid_t pid;
diff --git a/src/or/transports.c b/src/or/transports.c
index 6f07054..ba2c784 100644
--- a/src/or/transports.c
+++ b/src/or/transports.c
@@ -1388,6 +1388,11 @@ create_managed_proxy_environment(const managed_proxy_t *mp)
} else {
smartlist_add_asprintf(envs, "TOR_PT_EXTENDED_SERVER_PORT=");
}
+
+ /* All new versions of tor will keep stdin open, so PTs can use it
+ * as a reliable termination detection mechanism.
+ */
+ smartlist_add_asprintf(envs, "TOR_PT_EXIT_ON_STDIN_CLOSE=1");
} else {
/* If ClientTransportPlugin has a HTTPS/SOCKS proxy configured, set the
* TOR_PT_PROXY line.
diff --git a/src/test/test_util_slow.c b/src/test/test_util_slow.c
index a597ef3..dcd0c9a 100644
--- a/src/test/test_util_slow.c
+++ b/src/test/test_util_slow.c
@@ -107,9 +107,11 @@ run_util_spawn_background(const char *argv[], const char *expected_out,
#ifdef _WIN32
tt_assert(process_handle->stdout_pipe != INVALID_HANDLE_VALUE);
tt_assert(process_handle->stderr_pipe != INVALID_HANDLE_VALUE);
+ tt_assert(process_handle->stdin_pipe != INVALID_HANDLE_VALUE);
#else
tt_assert(process_handle->stdout_pipe >= 0);
tt_assert(process_handle->stderr_pipe >= 0);
+ tt_assert(process_handle->stdin_pipe >= 0);
#endif
/* Check stdout */
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