Commit 544a8afe authored by Nick Mathewson's avatar Nick Mathewson 🌉
Browse files

Merge remote branch 'sjmurdoch/bug1903'

parents 8f76f317 f7338d3b
......@@ -155,6 +155,7 @@
/src/test/Makefile
/src/test/Makefile.in
/src/test/test
/src/test/test-child
# /src/tools/
......
......@@ -2883,17 +2883,34 @@ load_windows_system_library(const TCHAR *library_name)
}
#endif
/** Format child_state and saved_errno as a hex string placed in hex_errno.
* Called between fork and _exit, so must be signal-handler safe */
/** Format <b>child_state</b> and <b>saved_errno</b> as a hex string placed in
* <b>hex_errno</b>. Called between fork and _exit, so must be signal-handler
* safe.
*
* <b>hex_errno</b> must have at least HEX_ERRNO_SIZE bytes available.
*
* The format of <b>hex_errno</b> is: "CHILD_STATE/ERRNO\n", left-padded
* with spaces. Note that there is no trailing \0. CHILD_STATE indicates where
* in the processs of starting the child process did the failure occur (see
* CHILD_STATE_* macros for definition), and SAVED_ERRNO is the value of
* errno when the failure occurred.
*/
void
format_helper_exit_status(unsigned char child_state, int saved_errno,
char *hex_errno)
{
/* Convert errno to be unsigned for hex conversion */
unsigned int unsigned_errno;
char *cur;
size_t i;
/* If errno is negative, negate it */
/* Fill hex_errno with spaces, and a trailing newline (memset may
not be signal handler safe, so we can't use it) */
for (i = 0; i < (HEX_ERRNO_SIZE - 1); i++)
hex_errno[i] = ' ';
hex_errno[HEX_ERRNO_SIZE - 1] = '\n';
/* Convert errno to be unsigned for hex conversion */
if (saved_errno < 0) {
unsigned_errno = (unsigned int) -saved_errno;
} else {
......@@ -2903,17 +2920,26 @@ format_helper_exit_status(unsigned char child_state, int saved_errno,
/* Convert errno to hex (start before \n) */
cur = hex_errno + HEX_ERRNO_SIZE - 2;
/* Check for overflow on first iteration of the loop */
if (cur < hex_errno)
return;
do {
*cur-- = "0123456789ABCDEF"[unsigned_errno % 16];
unsigned_errno /= 16;
} while (unsigned_errno != 0 && cur >= hex_errno);
/* Add on the minus side if errno was negative */
if (saved_errno < 0)
/* Prepend the minus sign if errno was negative */
if (saved_errno < 0 && cur >= hex_errno)
*cur-- = '-';
/* Leave a gap */
*cur-- = '/';
if (cur >= hex_errno)
*cur-- = '/';
/* Check for overflow on first iteration of the loop */
if (cur < hex_errno)
return;
/* Convert child_state to hex */
do {
......@@ -2938,13 +2964,20 @@ format_helper_exit_status(unsigned char child_state, int saved_errno,
#define SPAWN_ERROR_MESSAGE "ERR: Failed to spawn background process - code "
/** Start a program in the background. If <b>filename</b> contains a '/', then
* it will be treated as an absolute or relative path. Otherwise the system
* path will be searched for <b>filename</b>. Returns pid on success, otherwise
* returns -1.
* Some parts of this code are based on the POSIX subprocess module from Python
/** Start a program in the background. If <b>filename</b> contains a '/',
* then it will be treated as an absolute or relative path. Otherwise the
* system path will be searched for <b>filename</b>. The strings in
* <b>argv</b> will be passed as the command line arguments of the child
* program (following convention, argv[0] should normally be the filename of
* the executable). The last element of argv must be NULL. If the child
* program is launched, the PID will be returned and <b>stdout_read</b> and
* <b>stdout_err</b> will be set to file descriptors from which the stdout
* and stderr, respectively, output of the child program can be read, and the
* stdin of the child process shall be set to /dev/null. Otherwise returns
* -1. Some parts of this code are based on the POSIX subprocess module from
* Python.
*/
static int
int
tor_spawn_background(const char *const filename, int *stdout_read,
int *stderr_read, const char **argv)
{
......@@ -2974,16 +3007,12 @@ tor_spawn_background(const char *const filename, int *stdout_read,
and we are not allowed to use unsafe functions between fork and exec */
error_message_length = strlen(error_message);
/* Fill hex_errno with spaces, and a trailing newline */
memset(hex_errno, ' ', sizeof(hex_errno) - 1);
hex_errno[sizeof(hex_errno) - 1] = '\n';
child_state = CHILD_STATE_PIPE;
/* Set up pipe for redirecting stdout and stderr of child */
retval = pipe(stdout_pipe);
if (-1 == retval) {
log_err(LD_GENERAL,
log_warn(LD_GENERAL,
"Failed to set up pipe for stdout communication with child process: %s",
strerror(errno));
return -1;
......@@ -2991,7 +3020,7 @@ tor_spawn_background(const char *const filename, int *stdout_read,
retval = pipe(stderr_pipe);
if (-1 == retval) {
log_err(LD_GENERAL,
log_warn(LD_GENERAL,
"Failed to set up pipe for stderr communication with child process: %s",
strerror(errno));
return -1;
......@@ -3043,7 +3072,8 @@ tor_spawn_background(const char *const filename, int *stdout_read,
child_state = CHILD_STATE_CLOSEFD;
/* Close all other fds, including the read end of the pipe */
/* TODO: use closefrom if available */
/* XXX: use closefrom if available, or better still set FD_CLOEXEC
on all of Tor's open files */
for (fd = STDERR_FILENO + 1; fd < max_fd; fd++)
close(fd);
......@@ -3059,7 +3089,7 @@ tor_spawn_background(const char *const filename, int *stdout_read,
child_state = CHILD_STATE_FAILEXEC;
error:
/* TODO: are we leaking fds from the pipe? */
/* XXX: are we leaking fds from the pipe? */
format_helper_exit_status(child_state, errno, hex_errno);
......@@ -3075,7 +3105,7 @@ tor_spawn_background(const char *const filename, int *stdout_read,
/* In parent */
if (-1 == pid) {
log_err(LD_GENERAL, "Failed to fork child process: %s", strerror(errno));
log_warn(LD_GENERAL, "Failed to fork child process: %s", strerror(errno));
close(stdout_pipe[0]);
close(stdout_pipe[1]);
close(stderr_pipe[0]);
......@@ -3088,7 +3118,7 @@ tor_spawn_background(const char *const filename, int *stdout_read,
retval = close(stdout_pipe[1]);
if (-1 == retval) {
log_err(LD_GENERAL,
log_warn(LD_GENERAL,
"Failed to close write end of stdout pipe in parent process: %s",
strerror(errno));
/* Do not return -1, because the child is running, so the parent
......@@ -3099,7 +3129,7 @@ tor_spawn_background(const char *const filename, int *stdout_read,
retval = close(stderr_pipe[1]);
if (-1 == retval) {
log_err(LD_GENERAL,
log_warn(LD_GENERAL,
"Failed to close write end of stderr pipe in parent process: %s",
strerror(errno));
/* Do not return -1, because the child is running, so the parent
......@@ -3152,26 +3182,27 @@ log_from_pipe(FILE *stream, int severity, const char *executable,
} else {
/* No newline; check whether we overflowed the buffer */
if (!feof(stream))
log_err(LD_GENERAL,
log_warn(LD_GENERAL,
"Line from port forwarding helper was truncated: %s", buf);
/* TODO: What to do with this error? */
}
/* Check if buf starts with SPAWN_ERROR_MESSAGE */
if (strstr(buf, SPAWN_ERROR_MESSAGE) == buf) {
if (strcmpstart(buf, SPAWN_ERROR_MESSAGE) == 0) {
/* Parse error message */
int retval, child_state, saved_errno;
retval = sscanf(buf, SPAWN_ERROR_MESSAGE "%d/%d",
&child_state, &saved_errno);
retval = tor_sscanf(buf, SPAWN_ERROR_MESSAGE "%x/%x",
&child_state, &saved_errno);
if (retval == 2) {
log_err(LD_GENERAL,
log_warn(LD_GENERAL,
"Failed to start child process \"%s\" in state %d: %s",
executable, child_state, strerror(saved_errno));
if (child_status)
*child_status = 1;
} else {
/* Failed to parse message from child process, log it as error */
log_err(LD_GENERAL,
/* Failed to parse message from child process, log it as a
warning */
log_warn(LD_GENERAL,
"Unexpected message from port forwarding helper \"%s\": %s",
executable, buf);
}
......@@ -3237,7 +3268,7 @@ tor_check_port_forwarding(const char *filename, int dir_port, int or_port,
child_pid = tor_spawn_background(filename, &fd_out, &fd_err, argv);
if (child_pid < 0) {
log_err(LD_GENERAL, "Failed to start port forwarding helper %s",
log_warn(LD_GENERAL, "Failed to start port forwarding helper %s",
filename);
child_pid = -1;
return;
......@@ -3258,7 +3289,7 @@ tor_check_port_forwarding(const char *filename, int dir_port, int or_port,
/* Read from stdout/stderr and log result */
retval = 0;
stdout_status = log_from_pipe(stdout_read, LOG_INFO, filename, &retval);
stderr_status = log_from_pipe(stderr_read, LOG_ERR, filename, &retval);
stderr_status = log_from_pipe(stderr_read, LOG_WARN, filename, &retval);
if (retval) {
/* There was a problem in the child process */
time_to_run_helper = now + TIME_TO_EXEC_FWHELPER_FAIL;
......@@ -3280,7 +3311,7 @@ tor_check_port_forwarding(const char *filename, int dir_port, int or_port,
if (1 == retval) {
log_info(LD_GENERAL, "Port forwarding helper terminated");
} else {
log_err(LD_GENERAL, "Failed to read from port forwarding helper");
log_warn(LD_GENERAL, "Failed to read from port forwarding helper");
}
/* TODO: The child might not actually be finished (maybe it failed or
......
......@@ -350,6 +350,8 @@ HANDLE load_windows_system_library(const TCHAR *library_name);
#ifdef UTIL_PRIVATE
/* Prototypes for private functions only used by util.c (and unit tests) */
int tor_spawn_background(const char *const filename, int *stdout_read,
int *stderr_read, const char **argv);
void format_helper_exit_status(unsigned char child_state,
int saved_errno, char *hex_errno);
......
TESTS = test
noinst_PROGRAMS = test
noinst_PROGRAMS = test test-child
AM_CPPFLAGS = -DSHARE_DATADIR="\"$(datadir)\"" \
-DLOCALSTATEDIR="\"$(localstatedir)\"" \
......
#include <stdio.h>
/** Trivial test program which prints out its command line arguments so we can
* check if tor_spawn_background() works */
int
main(int argc, char **argv)
{
int i;
fprintf(stdout, "OUT\n");
fprintf(stderr, "ERR\n");
for (i = 0; i < argc; i++)
fprintf(stdout, "%s\n", argv[i]);
fprintf(stdout, "DONE\n");
return 0;
}
......@@ -1224,14 +1224,13 @@ test_util_load_win_lib(void *ptr)
static void
clear_hex_errno(char *hex_errno)
{
memset(hex_errno, ' ', HEX_ERRNO_SIZE - 2);
hex_errno[HEX_ERRNO_SIZE - 1] = '\n';
hex_errno[HEX_ERRNO_SIZE] = '\0';
memset(hex_errno, '\0', HEX_ERRNO_SIZE + 1);
}
static void
test_util_exit_status(void *ptr)
{
/* Leave an extra byte for a \0 so we can do string comparison */
char hex_errno[HEX_ERRNO_SIZE + 1];
(void)ptr;
......@@ -1260,6 +1259,164 @@ test_util_exit_status(void *ptr)
;
}
#ifndef MS_WINDOWS
/** Check that fgets waits until a full line, and not return a partial line, on
* a EAGAIN with a non-blocking pipe */
static void
test_util_fgets_eagain(void *ptr)
{
int test_pipe[2] = {-1, -1};
int retval;
ssize_t retlen;
char *retptr;
FILE *test_stream = NULL;
char buf[10];
(void)ptr;
/* Set up a pipe to test on */
retval = pipe(test_pipe);
tt_int_op(retval, >=, 0);
/* Set up the read-end to be non-blocking */
retval = fcntl(test_pipe[0], F_SETFL, O_NONBLOCK);
tt_int_op(retval, >=, 0);
/* Open it as a stdio stream */
test_stream = fdopen(test_pipe[0], "r");
tt_ptr_op(test_stream, !=, NULL);
/* Send in a partial line */
retlen = write(test_pipe[1], "A", 1);
tt_int_op(retlen, ==, 1);
retptr = fgets(buf, sizeof(buf), test_stream);
tt_want(retptr == NULL);
tt_int_op(errno, ==, EAGAIN);
/* Send in the rest */
retlen = write(test_pipe[1], "B\n", 2);
tt_int_op(retlen, ==, 2);
retptr = fgets(buf, sizeof(buf), test_stream);
tt_ptr_op(retptr, ==, buf);
tt_str_op(buf, ==, "AB\n");
/* Send in a full line */
retlen = write(test_pipe[1], "CD\n", 3);
tt_int_op(retlen, ==, 3);
retptr = fgets(buf, sizeof(buf), test_stream);
tt_ptr_op(retptr, ==, buf);
tt_str_op(buf, ==, "CD\n");
/* Send in a partial line */
retlen = write(test_pipe[1], "E", 1);
tt_int_op(retlen, ==, 1);
retptr = fgets(buf, sizeof(buf), test_stream);
tt_ptr_op(retptr, ==, NULL);
tt_int_op(errno, ==, EAGAIN);
/* Send in the rest */
retlen = write(test_pipe[1], "F\n", 2);
tt_int_op(retlen, ==, 2);
retptr = fgets(buf, sizeof(buf), test_stream);
tt_ptr_op(retptr, ==, buf);
tt_str_op(buf, ==, "EF\n");
/* Send in a full line and close */
retlen = write(test_pipe[1], "GH", 2);
tt_int_op(retlen, ==, 2);
retval = close(test_pipe[1]);
test_pipe[1] = -1;
tt_int_op(retval, ==, 0);
retptr = fgets(buf, sizeof(buf), test_stream);
tt_ptr_op(retptr, ==, buf);
tt_str_op(buf, ==, "GH");
/* Check for EOF */
retptr = fgets(buf, sizeof(buf), test_stream);
tt_ptr_op(retptr, ==, NULL);
tt_int_op(feof(test_stream), >, 0);
done:
if (test_stream != NULL)
fclose(test_stream);
if (test_pipe[0] != -1)
close(test_pipe[0]);
if (test_pipe[1] != -1)
close(test_pipe[1]);
}
#endif
#ifndef MS_WINDOWS
/** Helper function for testing tor_spawn_background */
static void
run_util_spawn_background(const char *argv[], const char *expected_out,
const char *expected_err, int expected_exit)
{
int stdout_pipe=-1, stderr_pipe=-1;
int retval, stat_loc;
pid_t pid;
ssize_t pos;
char stdout_buf[100], stderr_buf[100];
/* Start the program */
retval = tor_spawn_background(argv[0], &stdout_pipe, &stderr_pipe, argv);
tt_int_op(retval, >, 0);
tt_int_op(stdout_pipe, >, 0);
tt_int_op(stderr_pipe, >, 0);
pid = retval;
/* Check stdout */
pos = read(stdout_pipe, stdout_buf, sizeof(stdout_buf) - 1);
stdout_buf[pos] = '\0';
tt_int_op(pos, ==, strlen(expected_out));
tt_str_op(stdout_buf, ==, expected_out);
/* Check it terminated correctly */
retval = waitpid(pid, &stat_loc, 0);
tt_int_op(retval, ==, pid);
tt_assert(WIFEXITED(stat_loc));
tt_int_op(WEXITSTATUS(stat_loc), ==, expected_exit);
tt_assert(!WIFSIGNALED(stat_loc));
tt_assert(!WIFSTOPPED(stat_loc));
/* Check stderr */
pos = read(stderr_pipe, stderr_buf, sizeof(stderr_buf) - 1);
stderr_buf[pos] = '\0';
tt_int_op(pos, ==, strlen(expected_err));
tt_str_op(stderr_buf, ==, expected_err);
done:
;
}
/** Check that we can launch a process and read the output */
static void
test_util_spawn_background_ok(void *ptr)
{
const char *argv[] = {"src/test/test-child", "--test", NULL};
const char *expected_out = "OUT\nsrc/test/test-child\n--test\nDONE\n";
const char *expected_err = "ERR\n";
(void)ptr;
run_util_spawn_background(argv, expected_out, expected_err, 0);
}
/** Check that failing to find the executable works as expected */
static void
test_util_spawn_background_fail(void *ptr)
{
const char *argv[] = {"src/test/no-such-file", "--test", NULL};
const char *expected_out = "ERR: Failed to spawn background process "
"- code 9/2\n";
const char *expected_err = "";
(void)ptr;
run_util_spawn_background(argv, expected_out, expected_err, 255);
}
#endif
#define UTIL_LEGACY(name) \
{ #name, legacy_test_helper, 0, &legacy_setup, test_util_ ## name }
......@@ -1287,6 +1444,11 @@ struct testcase_t util_tests[] = {
UTIL_TEST(load_win_lib, 0),
#endif
UTIL_TEST(exit_status, 0),
#ifndef MS_WINDOWS
UTIL_TEST(fgets_eagain, TT_SKIP),
UTIL_TEST(spawn_background_ok, 0),
UTIL_TEST(spawn_background_fail, 0),
#endif
END_OF_TESTCASES
};
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