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Diffstat (limited to 'src/lib/process/subprocess.c')
| -rw-r--r-- | src/lib/process/subprocess.c | 1236 |
1 files changed, 1236 insertions, 0 deletions
diff --git a/src/lib/process/subprocess.c b/src/lib/process/subprocess.c new file mode 100644 index 0000000000..f4429d7f76 --- /dev/null +++ b/src/lib/process/subprocess.c @@ -0,0 +1,1236 @@ +/* Copyright (c) 2003, Roger Dingledine + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file subprocess.c + * \brief Launch and monitor other processes. + **/ + +#define SUBPROCESS_PRIVATE +#include "lib/process/subprocess.h" + +#include "lib/container/smartlist.h" +#include "lib/err/torerr.h" +#include "lib/log/log.h" +#include "lib/log/util_bug.h" +#include "lib/log/win32err.h" +#include "lib/malloc/malloc.h" +#include "lib/process/env.h" +#include "lib/process/waitpid.h" +#include "lib/string/compat_ctype.h" + +#ifdef HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif +#ifdef HAVE_SYS_PRCTL_H +#include <sys/prctl.h> +#endif +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif +#ifdef HAVE_SIGNAL_H +#include <signal.h> +#endif +#ifdef HAVE_FCNTL_H +#include <fcntl.h> +#endif +#ifdef HAVE_SYS_WAIT_H +#include <sys/wait.h> +#endif +#include <errno.h> +#include <string.h> + +/** Format a single argument for being put on a Windows command line. + * Returns a newly allocated string */ +static char * +format_win_cmdline_argument(const char *arg) +{ + char *formatted_arg; + char need_quotes; + const char *c; + int i; + int bs_counter = 0; + /* Backslash we can point to when one is inserted into the string */ + const char backslash = '\\'; + + /* Smartlist of *char */ + smartlist_t *arg_chars; + arg_chars = smartlist_new(); + + /* Quote string if it contains whitespace or is empty */ + need_quotes = (strchr(arg, ' ') || strchr(arg, '\t') || '\0' == arg[0]); + + /* Build up smartlist of *chars */ + for (c=arg; *c != '\0'; c++) { + if ('"' == *c) { + /* Double up backslashes preceding a quote */ + for (i=0; i<(bs_counter*2); i++) + smartlist_add(arg_chars, (void*)&backslash); + bs_counter = 0; + /* Escape the quote */ + smartlist_add(arg_chars, (void*)&backslash); + smartlist_add(arg_chars, (void*)c); + } else if ('\\' == *c) { + /* Count backslashes until we know whether to double up */ + bs_counter++; + } else { + /* Don't double up slashes preceding a non-quote */ + for (i=0; i<bs_counter; i++) + smartlist_add(arg_chars, (void*)&backslash); + bs_counter = 0; + smartlist_add(arg_chars, (void*)c); + } + } + /* Don't double up trailing backslashes */ + for (i=0; i<bs_counter; i++) + smartlist_add(arg_chars, (void*)&backslash); + + /* Allocate space for argument, quotes (if needed), and terminator */ + const size_t formatted_arg_len = smartlist_len(arg_chars) + + (need_quotes ? 2 : 0) + 1; + formatted_arg = tor_malloc_zero(formatted_arg_len); + + /* Add leading quote */ + i=0; + if (need_quotes) + formatted_arg[i++] = '"'; + + /* Add characters */ + SMARTLIST_FOREACH(arg_chars, char*, ch, + { + formatted_arg[i++] = *ch; + }); + + /* Add trailing quote */ + if (need_quotes) + formatted_arg[i++] = '"'; + formatted_arg[i] = '\0'; + + smartlist_free(arg_chars); + return formatted_arg; +} + +/** Format a command line for use on Windows, which takes the command as a + * string rather than string array. Follows the rules from "Parsing C++ + * Command-Line Arguments" in MSDN. Algorithm based on list2cmdline in the + * Python subprocess module. Returns a newly allocated string */ +char * +tor_join_win_cmdline(const char *argv[]) +{ + smartlist_t *argv_list; + char *joined_argv; + int i; + + /* Format each argument and put the result in a smartlist */ + argv_list = smartlist_new(); + for (i=0; argv[i] != NULL; i++) { + smartlist_add(argv_list, (void *)format_win_cmdline_argument(argv[i])); + } + + /* Join the arguments with whitespace */ + joined_argv = smartlist_join_strings(argv_list, " ", 0, NULL); + + /* Free the newly allocated arguments, and the smartlist */ + SMARTLIST_FOREACH(argv_list, char *, arg, + { + tor_free(arg); + }); + smartlist_free(argv_list); + + return joined_argv; +} + +#ifndef _WIN32 +/** 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+1 bytes available. + * + * The format of <b>hex_errno</b> is: "CHILD_STATE/ERRNO\n", left-padded + * with spaces. CHILD_STATE indicates where + * in the process 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. + * + * On success return the number of characters added to hex_errno, not counting + * the terminating NUL; return -1 on error. + */ +STATIC int +format_helper_exit_status(unsigned char child_state, int saved_errno, + char *hex_errno) +{ + unsigned int unsigned_errno; + int written, left; + char *cur; + size_t i; + int res = -1; + + /* 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) { + // Avoid overflow on the cast to unsigned int when result is INT_MIN + // by adding 1 to the signed int negative value, + // then, after it has been negated and cast to unsigned, + // adding the original 1 back (the double-addition is intentional). + // Otherwise, the cast to signed could cause a temporary int + // to equal INT_MAX + 1, which is undefined. + unsigned_errno = ((unsigned int) -(saved_errno + 1)) + 1; + } else { + unsigned_errno = (unsigned int) saved_errno; + } + + /* + * Count how many chars of space we have left, and keep a pointer into the + * current point in the buffer. + */ + left = HEX_ERRNO_SIZE+1; + cur = hex_errno; + + /* Emit child_state */ + written = format_hex_number_sigsafe(child_state, cur, left); + + if (written <= 0) + goto err; + + /* Adjust left and cur */ + left -= written; + cur += written; + if (left <= 0) + goto err; + + /* Now the '/' */ + *cur = '/'; + + /* Adjust left and cur */ + ++cur; + --left; + if (left <= 0) + goto err; + + /* Need minus? */ + if (saved_errno < 0) { + *cur = '-'; + ++cur; + --left; + if (left <= 0) + goto err; + } + + /* Emit unsigned_errno */ + written = format_hex_number_sigsafe(unsigned_errno, cur, left); + + if (written <= 0) + goto err; + + /* Adjust left and cur */ + left -= written; + cur += written; + + /* Check that we have enough space left for a newline and a NUL */ + if (left <= 1) + goto err; + + /* Emit the newline and NUL */ + *cur++ = '\n'; + *cur++ = '\0'; + + res = (int)(cur - hex_errno - 1); + + goto done; + + err: + /* + * In error exit, just write a '\0' in the first char so whatever called + * this at least won't fall off the end. + */ + *hex_errno = '\0'; + + done: + return res; +} +#endif /* !defined(_WIN32) */ + +/* Maximum number of file descriptors, if we cannot get it via sysconf() */ +#define DEFAULT_MAX_FD 256 + +/** Terminate the process of <b>process_handle</b>, if that process has not + * already exited. + * + * Return 0 if we succeeded in terminating the process (or if the process + * already exited), and -1 if we tried to kill the process but failed. + * + * Based on code originally borrowed from Python's os.kill. */ +int +tor_terminate_process(process_handle_t *process_handle) +{ +#ifdef _WIN32 + if (tor_get_exit_code(process_handle, 0, NULL) == PROCESS_EXIT_RUNNING) { + HANDLE handle = process_handle->pid.hProcess; + + if (!TerminateProcess(handle, 0)) + return -1; + else + return 0; + } +#else /* !(defined(_WIN32)) */ + if (process_handle->waitpid_cb) { + /* We haven't got a waitpid yet, so we can just kill off the process. */ + return kill(process_handle->pid, SIGTERM); + } +#endif /* defined(_WIN32) */ + + return 0; /* We didn't need to kill the process, so report success */ +} + +/** Return the Process ID of <b>process_handle</b>. */ +int +tor_process_get_pid(process_handle_t *process_handle) +{ +#ifdef _WIN32 + return (int) process_handle->pid.dwProcessId; +#else + return (int) process_handle->pid; +#endif +} + +#ifdef _WIN32 +HANDLE +tor_process_get_stdout_pipe(process_handle_t *process_handle) +{ + return process_handle->stdout_pipe; +} +#else /* !(defined(_WIN32)) */ +/* DOCDOC tor_process_get_stdout_pipe */ +int +tor_process_get_stdout_pipe(process_handle_t *process_handle) +{ + return process_handle->stdout_pipe; +} +#endif /* defined(_WIN32) */ + +/* DOCDOC process_handle_new */ +static process_handle_t * +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 /* defined(_WIN32) */ + + return out; +} + +#ifndef _WIN32 +/** Invoked when a process that we've launched via tor_spawn_background() has + * been found to have terminated. + */ +static void +process_handle_waitpid_cb(int status, void *arg) +{ + process_handle_t *process_handle = arg; + + process_handle->waitpid_exit_status = status; + clear_waitpid_callback(process_handle->waitpid_cb); + if (process_handle->status == PROCESS_STATUS_RUNNING) + process_handle->status = PROCESS_STATUS_NOTRUNNING; + process_handle->waitpid_cb = 0; +} +#endif /* !defined(_WIN32) */ + +/** + * @name child-process states + * + * Each of these values represents a possible state that a child process can + * be in. They're used to determine what to say when telling the parent how + * far along we were before failure. + * + * @{ + */ +#define CHILD_STATE_INIT 0 +#define CHILD_STATE_PIPE 1 +#define CHILD_STATE_MAXFD 2 +#define CHILD_STATE_FORK 3 +#define CHILD_STATE_DUPOUT 4 +#define CHILD_STATE_DUPERR 5 +#define CHILD_STATE_DUPIN 6 +#define CHILD_STATE_CLOSEFD 7 +#define CHILD_STATE_EXEC 8 +#define CHILD_STATE_FAILEXEC 9 +/** @} */ +/** + * Boolean. If true, then Tor may call execve or CreateProcess via + * tor_spawn_background. + **/ +static int may_spawn_background_process = 1; +/** + * Turn off may_spawn_background_process, so that all future calls to + * tor_spawn_background are guaranteed to fail. + **/ +void +tor_disable_spawning_background_processes(void) +{ + may_spawn_background_process = 0; +} +/** Start a program in the background. If <b>filename</b> contains a '/', then + * it will be treated as an absolute or relative path. Otherwise, on + * non-Windows systems, the system path will be searched for <b>filename</b>. + * On Windows, only the current directory will be searched. Here, to search the + * system path (as well as the application directory, current working + * directory, and system directories), set filename to NULL. + * + * 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, and this must be the case if <b>filename</b> is + * NULL). The last element of argv must be NULL. A handle to the child process + * will be returned in process_handle (which must be non-NULL). Read + * process_handle.status to find out if the process was successfully launched. + * For convenience, process_handle.status is returned by this function. + * + * Some parts of this code are based on the POSIX subprocess module from + * Python, and example code from + * http://msdn.microsoft.com/en-us/library/ms682499%28v=vs.85%29.aspx. + */ +int +tor_spawn_background(const char *const filename, const char **argv, + process_environment_t *env, + process_handle_t **process_handle_out) +{ + if (BUG(may_spawn_background_process == 0)) { + /* We should never reach this point if we're forbidden to spawn + * processes. Instead we should have caught the attempt earlier. */ + return PROCESS_STATUS_ERROR; + } + +#ifdef _WIN32 + HANDLE stdout_pipe_read = NULL; + 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; + + STARTUPINFOA siStartInfo; + BOOL retval = FALSE; + + SECURITY_ATTRIBUTES saAttr; + char *joined_argv; + + saAttr.nLength = sizeof(SECURITY_ATTRIBUTES); + saAttr.bInheritHandle = TRUE; + /* TODO: should we set explicit security attributes? (#2046, comment 5) */ + saAttr.lpSecurityDescriptor = NULL; + + /* Assume failure to start process */ + status = PROCESS_STATUS_ERROR; + + /* Set up pipe for stdout */ + if (!CreatePipe(&stdout_pipe_read, &stdout_pipe_write, &saAttr, 0)) { + log_warn(LD_GENERAL, + "Failed to create pipe for stdout communication with child process: %s", + format_win32_error(GetLastError())); + return status; + } + if (!SetHandleInformation(stdout_pipe_read, HANDLE_FLAG_INHERIT, 0)) { + log_warn(LD_GENERAL, + "Failed to configure pipe for stdout communication with child " + "process: %s", format_win32_error(GetLastError())); + return status; + } + + /* Set up pipe for stderr */ + if (!CreatePipe(&stderr_pipe_read, &stderr_pipe_write, &saAttr, 0)) { + log_warn(LD_GENERAL, + "Failed to create pipe for stderr communication with child process: %s", + format_win32_error(GetLastError())); + return status; + } + if (!SetHandleInformation(stderr_pipe_read, HANDLE_FLAG_INHERIT, 0)) { + log_warn(LD_GENERAL, + "Failed to configure pipe for stderr communication with child " + "process: %s", format_win32_error(GetLastError())); + 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(stdin_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 + */ + joined_argv = tor_join_win_cmdline(argv); + + process_handle = process_handle_new(); + process_handle->status = status; + + ZeroMemory(&(process_handle->pid), sizeof(PROCESS_INFORMATION)); + ZeroMemory(&siStartInfo, sizeof(STARTUPINFO)); + siStartInfo.cb = sizeof(STARTUPINFO); + siStartInfo.hStdError = stderr_pipe_write; + siStartInfo.hStdOutput = stdout_pipe_write; + siStartInfo.hStdInput = stdin_pipe_read; + siStartInfo.dwFlags |= STARTF_USESTDHANDLES; + + /* Create the child process */ + + retval = CreateProcessA(filename, // module name + joined_argv, // command line + /* TODO: should we set explicit security attributes? (#2046, comment 5) */ + NULL, // process security attributes + NULL, // primary thread security attributes + TRUE, // handles are inherited + /*(TODO: set CREATE_NEW CONSOLE/PROCESS_GROUP to make GetExitCodeProcess() + * work?) */ + CREATE_NO_WINDOW, // creation flags + (env==NULL) ? NULL : env->windows_environment_block, + NULL, // use parent's current directory + &siStartInfo, // STARTUPINFO pointer + &(process_handle->pid)); // receives PROCESS_INFORMATION + + tor_free(joined_argv); + + if (!retval) { + log_warn(LD_GENERAL, + "Failed to create child process %s: %s", filename?filename:argv[0], + format_win32_error(GetLastError())); + tor_free(process_handle); + } else { + /* 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; + } + + /* TODO: Close pipes on exit */ + *process_handle_out = process_handle; + return status; +#else /* !(defined(_WIN32)) */ + pid_t pid; + int stdout_pipe[2]; + int stderr_pipe[2]; + int stdin_pipe[2]; + int fd, retval; + process_handle_t *process_handle; + int status; + + const char *error_message = SPAWN_ERROR_MESSAGE; + size_t error_message_length; + + /* Represents where in the process of spawning the program is; + this is used for printing out the error message */ + unsigned char child_state = CHILD_STATE_INIT; + + char hex_errno[HEX_ERRNO_SIZE + 2]; /* + 1 should be sufficient actually */ + + static int max_fd = -1; + + status = PROCESS_STATUS_ERROR; + + /* We do the strlen here because strlen() is not signal handler safe, + and we are not allowed to use unsafe functions between fork and exec */ + error_message_length = strlen(error_message); + + // child_state = CHILD_STATE_PIPE; + + /* Set up pipe for redirecting stdout, stderr, and stdin of child */ + retval = pipe(stdout_pipe); + if (-1 == retval) { + log_warn(LD_GENERAL, + "Failed to set up pipe for stdout communication with child process: %s", + strerror(errno)); + return status; + } + + retval = pipe(stderr_pipe); + if (-1 == retval) { + log_warn(LD_GENERAL, + "Failed to set up pipe for stderr communication with child process: %s", + strerror(errno)); + + close(stdout_pipe[0]); + close(stdout_pipe[1]); + + 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 + if (-1 == max_fd) { + max_fd = (int) sysconf(_SC_OPEN_MAX); + if (max_fd == -1) { + max_fd = DEFAULT_MAX_FD; + log_warn(LD_GENERAL, + "Cannot find maximum file descriptor, assuming %d", max_fd); + } + } +#else /* !(defined(_SC_OPEN_MAX)) */ + max_fd = DEFAULT_MAX_FD; +#endif /* defined(_SC_OPEN_MAX) */ + + // child_state = CHILD_STATE_FORK; + + pid = fork(); + if (0 == pid) { + /* In child */ + +#if defined(HAVE_SYS_PRCTL_H) && defined(__linux__) + /* Attempt to have the kernel issue a SIGTERM if the parent + * goes away. Certain attributes of the binary being execve()ed + * will clear this during the execve() call, but it's better + * than nothing. + */ + prctl(PR_SET_PDEATHSIG, SIGTERM); +#endif /* defined(HAVE_SYS_PRCTL_H) && defined(__linux__) */ + + child_state = CHILD_STATE_DUPOUT; + + /* Link child stdout to the write end of the pipe */ + retval = dup2(stdout_pipe[1], STDOUT_FILENO); + if (-1 == retval) + goto error; + + child_state = CHILD_STATE_DUPERR; + + /* Link child stderr to the write end of the pipe */ + retval = dup2(stderr_pipe[1], STDERR_FILENO); + if (-1 == retval) + goto error; + + child_state = CHILD_STATE_DUPIN; + + /* 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; + + close(stderr_pipe[0]); + close(stderr_pipe[1]); + close(stdout_pipe[0]); + close(stdout_pipe[1]); + 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 + * this needless. */ + for (fd = STDERR_FILENO + 1; fd < max_fd; fd++) { + close(fd); + } + + // child_state = CHILD_STATE_EXEC; + + /* Call the requested program. We need the cast because + execvp doesn't define argv as const, even though it + does not modify the arguments */ + if (env) + execve(filename, (char *const *) argv, env->unixoid_environment_block); + else { + static char *new_env[] = { NULL }; + execve(filename, (char *const *) argv, new_env); + } + + /* If we got here, the exec or open(/dev/null) failed */ + + child_state = CHILD_STATE_FAILEXEC; + + error: + { + /* XXX: are we leaking fds from the pipe? */ + int n, err=0; + ssize_t nbytes; + + n = format_helper_exit_status(child_state, errno, hex_errno); + + if (n >= 0) { + /* Write the error message. GCC requires that we check the return + value, but there is nothing we can do if it fails */ + /* TODO: Don't use STDOUT, use a pipe set up just for this purpose */ + nbytes = write(STDOUT_FILENO, error_message, error_message_length); + err = (nbytes < 0); + nbytes = write(STDOUT_FILENO, hex_errno, n); + err += (nbytes < 0); + } + + _exit(err?254:255); // exit ok: in child. + } + + /* Never reached, but avoids compiler warning */ + return status; // LCOV_EXCL_LINE + } + + /* In parent */ + + 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]); + close(stderr_pipe[1]); + return status; + } + + process_handle = process_handle_new(); + process_handle->status = status; + process_handle->pid = pid; + + /* TODO: If the child process forked but failed to exec, waitpid it */ + + /* Return read end of the pipes to caller, and close write end */ + process_handle->stdout_pipe = stdout_pipe[0]; + retval = close(stdout_pipe[1]); + + if (-1 == retval) { + log_warn(LD_GENERAL, + "Failed to close write end of stdout pipe in parent process: %s", + strerror(errno)); + } + + process_handle->waitpid_cb = set_waitpid_callback(pid, + process_handle_waitpid_cb, + process_handle); + + process_handle->stderr_pipe = stderr_pipe[0]; + retval = close(stderr_pipe[1]); + + if (-1 == retval) { + log_warn(LD_GENERAL, + "Failed to close write end of stderr pipe in parent process: %s", + 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 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 || + 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)); + } + + *process_handle_out = process_handle; + return status; +#endif /* defined(_WIN32) */ +} + +/** Destroy all resources allocated by the process handle in + * <b>process_handle</b>. + * If <b>also_terminate_process</b> is true, also terminate the + * process of the process handle. */ +MOCK_IMPL(void, +tor_process_handle_destroy,(process_handle_t *process_handle, + int also_terminate_process)) +{ + if (!process_handle) + return; + + if (also_terminate_process) { + if (tor_terminate_process(process_handle) < 0) { + const char *errstr = +#ifdef _WIN32 + format_win32_error(GetLastError()); +#else + strerror(errno); +#endif + log_notice(LD_GENERAL, "Failed to terminate process with " + "PID '%d' ('%s').", tor_process_get_pid(process_handle), + errstr); + } else { + log_info(LD_GENERAL, "Terminated process with PID '%d'.", + tor_process_get_pid(process_handle)); + } + } + + process_handle->status = PROCESS_STATUS_NOTRUNNING; + +#ifdef _WIN32 + if (process_handle->stdout_pipe) + CloseHandle(process_handle->stdout_pipe); + + if (process_handle->stderr_pipe) + CloseHandle(process_handle->stderr_pipe); + + if (process_handle->stdin_pipe) + CloseHandle(process_handle->stdin_pipe); +#else /* !(defined(_WIN32)) */ + close(process_handle->stdout_pipe); + close(process_handle->stderr_pipe); + close(process_handle->stdin_pipe); + + clear_waitpid_callback(process_handle->waitpid_cb); +#endif /* defined(_WIN32) */ + + memset(process_handle, 0x0f, sizeof(process_handle_t)); + tor_free(process_handle); +} + +/** Get the exit code of a process specified by <b>process_handle</b> and store + * it in <b>exit_code</b>, if set to a non-NULL value. If <b>block</b> is set + * to true, the call will block until the process has exited. Otherwise if + * the process is still running, the function will return + * PROCESS_EXIT_RUNNING, and exit_code will be left unchanged. Returns + * PROCESS_EXIT_EXITED if the process did exit. If there is a failure, + * PROCESS_EXIT_ERROR will be returned and the contents of exit_code (if + * non-NULL) will be undefined. N.B. Under *nix operating systems, this will + * probably not work in Tor, because waitpid() is called in main.c to reap any + * terminated child processes.*/ +int +tor_get_exit_code(process_handle_t *process_handle, + int block, int *exit_code) +{ +#ifdef _WIN32 + DWORD retval; + BOOL success; + + if (block) { + /* Wait for the process to exit */ + retval = WaitForSingleObject(process_handle->pid.hProcess, INFINITE); + if (retval != WAIT_OBJECT_0) { + log_warn(LD_GENERAL, "WaitForSingleObject() failed (%d): %s", + (int)retval, format_win32_error(GetLastError())); + return PROCESS_EXIT_ERROR; + } + } else { + retval = WaitForSingleObject(process_handle->pid.hProcess, 0); + if (WAIT_TIMEOUT == retval) { + /* Process has not exited */ + return PROCESS_EXIT_RUNNING; + } else if (retval != WAIT_OBJECT_0) { + log_warn(LD_GENERAL, "WaitForSingleObject() failed (%d): %s", + (int)retval, format_win32_error(GetLastError())); + return PROCESS_EXIT_ERROR; + } + } + + if (exit_code != NULL) { + success = GetExitCodeProcess(process_handle->pid.hProcess, + (PDWORD)exit_code); + if (!success) { + log_warn(LD_GENERAL, "GetExitCodeProcess() failed: %s", + format_win32_error(GetLastError())); + return PROCESS_EXIT_ERROR; + } + } +#else /* !(defined(_WIN32)) */ + int stat_loc; + int retval; + + if (process_handle->waitpid_cb) { + /* We haven't processed a SIGCHLD yet. */ + retval = waitpid(process_handle->pid, &stat_loc, block?0:WNOHANG); + if (retval == process_handle->pid) { + clear_waitpid_callback(process_handle->waitpid_cb); + process_handle->waitpid_cb = NULL; + process_handle->waitpid_exit_status = stat_loc; + } + } else { + /* We already got a SIGCHLD for this process, and handled it. */ + retval = process_handle->pid; + stat_loc = process_handle->waitpid_exit_status; + } + + if (!block && 0 == retval) { + /* Process has not exited */ + return PROCESS_EXIT_RUNNING; + } else if (retval != process_handle->pid) { + log_warn(LD_GENERAL, "waitpid() failed for PID %d: %s", + (int)process_handle->pid, strerror(errno)); + return PROCESS_EXIT_ERROR; + } + + if (!WIFEXITED(stat_loc)) { + log_warn(LD_GENERAL, "Process %d did not exit normally", + (int)process_handle->pid); + return PROCESS_EXIT_ERROR; + } + + if (exit_code != NULL) + *exit_code = WEXITSTATUS(stat_loc); +#endif /* defined(_WIN32) */ + + return PROCESS_EXIT_EXITED; +} + +#ifdef _WIN32 +/** Read from a handle <b>h</b> into <b>buf</b>, up to <b>count</b> bytes. If + * <b>hProcess</b> is NULL, the function will return immediately if there is + * nothing more to read. Otherwise <b>hProcess</b> should be set to the handle + * to the process owning the <b>h</b>. In this case, the function will exit + * only once the process has exited, or <b>count</b> bytes are read. Returns + * the number of bytes read, or -1 on error. */ +ssize_t +tor_read_all_handle(HANDLE h, char *buf, size_t count, + const process_handle_t *process) +{ + size_t numread = 0; + BOOL retval; + DWORD byte_count; + BOOL process_exited = FALSE; + + if (count > SIZE_T_CEILING || count > SSIZE_MAX) + return -1; + + while (numread < count) { + /* Check if there is anything to read */ + retval = PeekNamedPipe(h, NULL, 0, NULL, &byte_count, NULL); + if (!retval) { + log_warn(LD_GENERAL, + "Failed to peek from handle: %s", + format_win32_error(GetLastError())); + return -1; + } else if (0 == byte_count) { + /* Nothing available: process exited or it is busy */ + + /* Exit if we don't know whether the process is running */ + if (NULL == process) + break; + + /* The process exited and there's nothing left to read from it */ + if (process_exited) + break; + + /* If process is not running, check for output one more time in case + it wrote something after the peek was performed. Otherwise keep on + waiting for output */ + tor_assert(process != NULL); + byte_count = WaitForSingleObject(process->pid.hProcess, 0); + if (WAIT_TIMEOUT != byte_count) + process_exited = TRUE; + + continue; + } + + /* There is data to read; read it */ + retval = ReadFile(h, buf+numread, count-numread, &byte_count, NULL); + tor_assert(byte_count + numread <= count); + if (!retval) { + log_warn(LD_GENERAL, "Failed to read from handle: %s", + format_win32_error(GetLastError())); + return -1; + } else if (0 == byte_count) { + /* End of file */ + break; + } + numread += byte_count; + } + return (ssize_t)numread; +} +#else /* !(defined(_WIN32)) */ +/** Read from a handle <b>fd</b> into <b>buf</b>, up to <b>count</b> bytes. If + * <b>process</b> is NULL, the function will return immediately if there is + * nothing more to read. Otherwise data will be read until end of file, or + * <b>count</b> bytes are read. Returns the number of bytes read, or -1 on + * error. Sets <b>eof</b> to true if <b>eof</b> is not NULL and the end of the + * file has been reached. */ +ssize_t +tor_read_all_handle(int fd, char *buf, size_t count, + const process_handle_t *process, + int *eof) +{ + size_t numread = 0; + ssize_t result; + + if (eof) + *eof = 0; + + if (count > SIZE_T_CEILING || count > SSIZE_MAX) + return -1; + + while (numread < count) { + result = read(fd, buf+numread, count-numread); + + if (result == 0) { + log_debug(LD_GENERAL, "read() reached end of file"); + if (eof) + *eof = 1; + break; + } else if (result < 0 && errno == EAGAIN) { + if (process) + continue; + else + break; + } else if (result < 0) { + log_warn(LD_GENERAL, "read() failed: %s", strerror(errno)); + return -1; + } + + numread += result; + } + + log_debug(LD_GENERAL, "read() read %d bytes from handle", (int)numread); + return (ssize_t)numread; +} +#endif /* defined(_WIN32) */ + +/** Read from stdout of a process until the process exits. */ +ssize_t +tor_read_all_from_process_stdout(const process_handle_t *process_handle, + char *buf, size_t count) +{ +#ifdef _WIN32 + return tor_read_all_handle(process_handle->stdout_pipe, buf, count, + process_handle); +#else + return tor_read_all_handle(process_handle->stdout_pipe, buf, count, + process_handle, NULL); +#endif /* defined(_WIN32) */ +} + +/** Read from stdout of a process until the process exits. */ +ssize_t +tor_read_all_from_process_stderr(const process_handle_t *process_handle, + char *buf, size_t count) +{ +#ifdef _WIN32 + return tor_read_all_handle(process_handle->stderr_pipe, buf, count, + process_handle); +#else + return tor_read_all_handle(process_handle->stderr_pipe, buf, count, + process_handle, NULL); +#endif /* defined(_WIN32) */ +} + +/** Return a string corresponding to <b>stream_status</b>. */ +const char * +stream_status_to_string(enum stream_status stream_status) +{ + switch (stream_status) { + case IO_STREAM_OKAY: + return "okay"; + case IO_STREAM_EAGAIN: + return "temporarily unavailable"; + case IO_STREAM_TERM: + return "terminated"; + case IO_STREAM_CLOSED: + return "closed"; + default: + tor_fragile_assert(); + return "unknown"; + } +} + +/** Split buf into lines, and add to smartlist. The buffer <b>buf</b> will be + * modified. The resulting smartlist will consist of pointers to buf, so there + * is no need to free the contents of sl. <b>buf</b> must be a NUL-terminated + * string. <b>len</b> should be set to the length of the buffer excluding the + * NUL. Non-printable characters (including NUL) will be replaced with "." */ +int +tor_split_lines(smartlist_t *sl, char *buf, int len) +{ + /* Index in buf of the start of the current line */ + int start = 0; + /* Index in buf of the current character being processed */ + int cur = 0; + /* Are we currently in a line */ + char in_line = 0; + + /* Loop over string */ + while (cur < len) { + /* Loop until end of line or end of string */ + for (; cur < len; cur++) { + if (in_line) { + if ('\r' == buf[cur] || '\n' == buf[cur]) { + /* End of line */ + buf[cur] = '\0'; + /* Point cur to the next line */ + cur++; + /* Line starts at start and ends with a nul */ + break; + } else { + if (!TOR_ISPRINT(buf[cur])) + buf[cur] = '.'; + } + } else { + if ('\r' == buf[cur] || '\n' == buf[cur]) { + /* Skip leading vertical space */ + ; + } else { + in_line = 1; + start = cur; + if (!TOR_ISPRINT(buf[cur])) + buf[cur] = '.'; + } + } + } + /* We are at the end of the line or end of string. If in_line is true there + * is a line which starts at buf+start and ends at a NUL. cur points to + * the character after the NUL. */ + if (in_line) + smartlist_add(sl, (void *)(buf+start)); + in_line = 0; + } + return smartlist_len(sl); +} + +#ifdef _WIN32 + +/** Return a smartlist containing lines outputted from + * <b>handle</b>. Return NULL on error, and set + * <b>stream_status_out</b> appropriately. */ +MOCK_IMPL(smartlist_t *, +tor_get_lines_from_handle, (HANDLE *handle, + enum stream_status *stream_status_out)) +{ + int pos; + char stdout_buf[600] = {0}; + smartlist_t *lines = NULL; + + tor_assert(stream_status_out); + + *stream_status_out = IO_STREAM_TERM; + + pos = tor_read_all_handle(handle, stdout_buf, sizeof(stdout_buf) - 1, NULL); + if (pos < 0) { + *stream_status_out = IO_STREAM_TERM; + return NULL; + } + if (pos == 0) { + *stream_status_out = IO_STREAM_EAGAIN; + return NULL; + } + + /* End with a null even if there isn't a \r\n at the end */ + /* TODO: What if this is a partial line? */ + stdout_buf[pos] = '\0'; + + /* Split up the buffer */ + lines = smartlist_new(); + tor_split_lines(lines, stdout_buf, pos); + + /* Currently 'lines' is populated with strings residing on the + stack. Replace them with their exact copies on the heap: */ + SMARTLIST_FOREACH(lines, char *, line, + SMARTLIST_REPLACE_CURRENT(lines, line, tor_strdup(line))); + + *stream_status_out = IO_STREAM_OKAY; + + return lines; +} + +#else /* !(defined(_WIN32)) */ + +/** Return a smartlist containing lines outputted from + * <b>fd</b>. Return NULL on error, and set + * <b>stream_status_out</b> appropriately. */ +MOCK_IMPL(smartlist_t *, +tor_get_lines_from_handle, (int fd, enum stream_status *stream_status_out)) +{ + enum stream_status stream_status; + char stdout_buf[400]; + smartlist_t *lines = NULL; + + while (1) { + memset(stdout_buf, 0, sizeof(stdout_buf)); + + stream_status = get_string_from_pipe(fd, + stdout_buf, sizeof(stdout_buf) - 1); + if (stream_status != IO_STREAM_OKAY) + goto done; + + if (!lines) lines = smartlist_new(); + smartlist_split_string(lines, stdout_buf, "\n", 0, 0); + } + + done: + *stream_status_out = stream_status; + return lines; +} + +#endif /* defined(_WIN32) */ + +/** Reads from <b>fd</b> and stores input in <b>buf_out</b> making + * sure it's below <b>count</b> bytes. + * If the string has a trailing newline, we strip it off. + * + * This function is specifically created to handle input from managed + * proxies, according to the pluggable transports spec. Make sure it + * fits your needs before using it. + * + * Returns: + * IO_STREAM_CLOSED: If the stream is closed. + * IO_STREAM_EAGAIN: If there is nothing to read and we should check back + * later. + * IO_STREAM_TERM: If something is wrong with the stream. + * IO_STREAM_OKAY: If everything went okay and we got a string + * in <b>buf_out</b>. */ +enum stream_status +get_string_from_pipe(int fd, char *buf_out, size_t count) +{ + ssize_t ret; + + tor_assert(count <= INT_MAX); + + ret = read(fd, buf_out, count); + + if (ret == 0) + return IO_STREAM_CLOSED; + else if (ret < 0 && errno == EAGAIN) + return IO_STREAM_EAGAIN; + else if (ret < 0) + return IO_STREAM_TERM; + + if (buf_out[ret - 1] == '\n') { + /* Remove the trailing newline */ + buf_out[ret - 1] = '\0'; + } else + buf_out[ret] = '\0'; + + return IO_STREAM_OKAY; +} |