diff options
Diffstat (limited to 'src/common/util.c')
| -rw-r--r-- | src/common/util.c | 1206 |
1 files changed, 1190 insertions, 16 deletions
diff --git a/src/common/util.c b/src/common/util.c index de1ca3684d..79e09e4f59 100644 --- a/src/common/util.c +++ b/src/common/util.c @@ -14,6 +14,10 @@ #define _GNU_SOURCE #include "orconfig.h" +#ifdef HAVE_FCNTL_H +#include <fcntl.h> +#endif +#define UTIL_PRIVATE #include "util.h" #include "torlog.h" #undef log @@ -27,6 +31,7 @@ #include <direct.h> #include <process.h> #include <tchar.h> +#include <Winbase.h> #else #include <dirent.h> #include <pwd.h> @@ -42,6 +47,7 @@ #include <stdio.h> #include <string.h> #include <assert.h> +#include <signal.h> #ifdef HAVE_NETINET_IN_H #include <netinet/in.h> @@ -67,9 +73,6 @@ #ifdef HAVE_SYS_FCNTL_H #include <sys/fcntl.h> #endif -#ifdef HAVE_FCNTL_H -#include <fcntl.h> -#endif #ifdef HAVE_TIME_H #include <time.h> #endif @@ -87,6 +90,9 @@ #ifdef HAVE_MALLOC_NP_H #include <malloc_np.h> #endif +#ifdef HAVE_SYS_WAIT_H +#include <sys/wait.h> +#endif /* ===== * Memory management @@ -417,6 +423,32 @@ round_uint64_to_next_multiple_of(uint64_t number, uint64_t divisor) return number; } +/** Return the number of bits set in <b>v</b>. */ +int +n_bits_set_u8(uint8_t v) +{ + static const int nybble_table[] = { + 0, /* 0000 */ + 1, /* 0001 */ + 1, /* 0010 */ + 2, /* 0011 */ + 1, /* 0100 */ + 2, /* 0101 */ + 2, /* 0110 */ + 3, /* 0111 */ + 1, /* 1000 */ + 2, /* 1001 */ + 2, /* 1010 */ + 3, /* 1011 */ + 2, /* 1100 */ + 3, /* 1101 */ + 3, /* 1110 */ + 4, /* 1111 */ + }; + + return nybble_table[v & 15] + nybble_table[v>>4]; +} + /* ===== * String manipulation * ===== */ @@ -500,6 +532,23 @@ tor_strisnonupper(const char *s) return 1; } +/** As strcmp, except that either string may be NULL. The NULL string is + * considered to be before any non-NULL string. */ +int +strcmp_opt(const char *s1, const char *s2) +{ + if (!s1) { + if (!s2) + return 0; + else + return -1; + } else if (!s2) { + return 1; + } else { + return strcmp(s1, s2); + } +} + /** Compares the first strlen(s2) characters of s1 with s2. Returns as for * strcmp. */ @@ -722,6 +771,34 @@ find_str_at_start_of_line(const char *haystack, const char *needle) return NULL; } +/** Returns true if <b>string</b> could be a C identifier. + A C identifier must begin with a letter or an underscore and the + rest of its characters can be letters, numbers or underscores. No + length limit is imposed. */ +int +string_is_C_identifier(const char *string) +{ + size_t iter; + size_t length = strlen(string); + if (!length) + return 0; + + for (iter = 0; iter < length ; iter++) { + if (iter == 0) { + if (!(TOR_ISALPHA(string[iter]) || + string[iter] == '_')) + return 0; + } else { + if (!(TOR_ISALPHA(string[iter]) || + TOR_ISDIGIT(string[iter]) || + string[iter] == '_')) + return 0; + } + } + + return 1; +} + /** Return true iff the 'len' bytes at 'mem' are all zero. */ int tor_mem_is_zero(const char *mem, size_t len) @@ -958,7 +1035,7 @@ esc_for_log(const char *s) char *result, *outp; size_t len = 3; if (!s) { - return tor_strdup(""); + return tor_strdup("(null)"); } for (cp = s; *cp; ++cp) { @@ -1698,6 +1775,8 @@ check_private_dir(const char *dirname, cpd_check_t check, struct passwd *pw = NULL; uid_t running_uid; gid_t running_gid; +#else + (void)effective_user; #endif tor_assert(dirname); @@ -1897,7 +1976,7 @@ start_writing_to_file(const char *fname, int open_flags, int mode, if (open_flags & O_BINARY) new_file->binary = 1; - new_file->fd = open(open_name, open_flags, mode); + new_file->fd = tor_open_cloexec(open_name, open_flags, mode); if (new_file->fd < 0) { log_warn(LD_FS, "Couldn't open \"%s\" (%s) for writing: %s", open_name, fname, strerror(errno)); @@ -2118,7 +2197,7 @@ read_file_to_str(const char *filename, int flags, struct stat *stat_out) tor_assert(filename); - fd = open(filename,O_RDONLY|(bin?O_BINARY:O_TEXT),0); + fd = tor_open_cloexec(filename,O_RDONLY|(bin?O_BINARY:O_TEXT),0); if (fd<0) { int severity = LOG_WARN; int save_errno = errno; @@ -2504,18 +2583,21 @@ digit_to_num(char d) * success, store the result in <b>out</b>, advance bufp to the next * character, and return 0. On failure, return -1. */ static int -scan_unsigned(const char **bufp, unsigned *out, int width) +scan_unsigned(const char **bufp, unsigned *out, int width, int base) { unsigned result = 0; int scanned_so_far = 0; + const int hex = base==16; + tor_assert(base == 10 || base == 16); if (!bufp || !*bufp || !out) return -1; if (width<0) width=MAX_SCANF_WIDTH; - while (**bufp && TOR_ISDIGIT(**bufp) && scanned_so_far < width) { - int digit = digit_to_num(*(*bufp)++); - unsigned new_result = result * 10 + digit; + while (**bufp && (hex?TOR_ISXDIGIT(**bufp):TOR_ISDIGIT(**bufp)) + && scanned_so_far < width) { + int digit = hex?hex_decode_digit(*(*bufp)++):digit_to_num(*(*bufp)++); + unsigned new_result = result * base + digit; if (new_result > UINT32_MAX || new_result < result) return -1; /* over/underflow. */ result = new_result; @@ -2577,11 +2659,12 @@ tor_vsscanf(const char *buf, const char *pattern, va_list ap) if (!width) /* No zero-width things. */ return -1; } - if (*pattern == 'u') { + if (*pattern == 'u' || *pattern == 'x') { unsigned *u = va_arg(ap, unsigned *); + const int base = (*pattern == 'u') ? 10 : 16; if (!*buf) return n_matched; - if (scan_unsigned(&buf, u, width)<0) + if (scan_unsigned(&buf, u, width, base)<0) return n_matched; ++pattern; ++n_matched; @@ -2618,9 +2701,9 @@ tor_vsscanf(const char *buf, const char *pattern, va_list ap) /** Minimal sscanf replacement: parse <b>buf</b> according to <b>pattern</b> * and store the results in the corresponding argument fields. Differs from - * sscanf in that it: Only handles %u and %Ns. Does not handle arbitrarily - * long widths. %u does not consume any space. Is locale-independent. - * Returns -1 on malformed patterns. + * sscanf in that it: Only handles %u and %x and %Ns. Does not handle + * arbitrarily long widths. %u and %x do not consume any space. Is + * locale-independent. Returns -1 on malformed patterns. * * (As with other locale-independent functions, we need this to parse data that * is in ASCII without worrying that the C library's locale-handling will make @@ -2637,6 +2720,30 @@ tor_sscanf(const char *buf, const char *pattern, ...) return r; } +/** Append the string produced by tor_asprintf(<b>pattern</b>, <b>...</b>) + * to <b>sl</b>. */ +void +smartlist_asprintf_add(struct smartlist_t *sl, const char *pattern, ...) +{ + va_list ap; + va_start(ap, pattern); + smartlist_vasprintf_add(sl, pattern, ap); + va_end(ap); +} + +/** va_list-based backend of smartlist_asprintf_add. */ +void +smartlist_vasprintf_add(struct smartlist_t *sl, const char *pattern, + va_list args) +{ + char *str = NULL; + + tor_vasprintf(&str, pattern, args); + tor_assert(str != NULL); + + smartlist_add(sl, str); +} + /** Return a new list containing the filenames in the directory <b>dirname</b>. * Return NULL on error or if <b>dirname</b> is not a directory. */ @@ -2814,7 +2921,7 @@ finish_daemon(const char *desired_cwd) exit(1); } - nullfd = open("/dev/null", O_RDWR); + nullfd = tor_open_cloexec("/dev/null", O_RDWR, 0); if (nullfd < 0) { log_err(LD_GENERAL,"/dev/null can't be opened. Exiting."); exit(1); @@ -2885,3 +2992,1070 @@ load_windows_system_library(const TCHAR *library_name) } #endif +/** 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_create(); + + /* 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 */ + formatted_arg = tor_malloc(sizeof(char) * + (smartlist_len(arg_chars) + (need_quotes?2:0) + 1)); + + /* Add leading quote */ + i=0; + if (need_quotes) + formatted_arg[i++] = '"'; + + /* Add characters */ + SMARTLIST_FOREACH(arg_chars, char*, c, + { + formatted_arg[i++] = *c; + }); + + /* 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_create(); + 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; +} + +/** 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) +{ + unsigned int unsigned_errno; + char *cur; + size_t i; + + /* 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 { + unsigned_errno = (unsigned 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); + + /* Prepend the minus sign if errno was negative */ + if (saved_errno < 0 && cur >= hex_errno) + *cur-- = '-'; + + /* Leave a gap */ + 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 { + *cur-- = "0123456789ABCDEF"[child_state % 16]; + child_state /= 16; + } while (child_state != 0 && cur >= hex_errno); +} + +/* Maximum number of file descriptors, if we cannot get it via sysconf() */ +#define DEFAULT_MAX_FD 256 + +/** Terminate process running at PID <b>pid</b>. + * Code borrowed from Python's os.kill. */ +int +tor_terminate_process(pid_t pid) +{ +#ifdef MS_WINDOWS + HANDLE handle; + /* If the signal is outside of what GenerateConsoleCtrlEvent can use, + attempt to open and terminate the process. */ + handle = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid); + if (!handle) + return -1; + + if (!TerminateProcess(handle, 0)) + return -1; + else + return 0; +#else /* Unix */ + return kill(pid, SIGTERM); +#endif +} + +#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_REDIRECT 6 +#define CHILD_STATE_CLOSEFD 7 +#define CHILD_STATE_EXEC 8 +#define CHILD_STATE_FAILEXEC 9 + +/** 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, + const char **envp, + process_handle_t *process_handle) +{ +#ifdef MS_WINDOWS + HANDLE stdout_pipe_read = NULL; + HANDLE stdout_pipe_write = NULL; + HANDLE stderr_pipe_read = NULL; + HANDLE stderr_pipe_write = NULL; + + STARTUPINFO siStartInfo; + BOOL retval = FALSE; + + SECURITY_ATTRIBUTES saAttr; + char *joined_argv; + + /* process_handle must not be NULL */ + tor_assert(process_handle != NULL); + + 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 */ + memset(process_handle, 0, sizeof(process_handle_t)); + process_handle->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 process_handle->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 process_handle->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 process_handle->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 process_handle->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); + + 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 = NULL; + siStartInfo.dwFlags |= STARTF_USESTDHANDLES; + + /* Create the child process */ + + retval = CreateProcess(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?) */ + 0, // creation flags + NULL, // use parent's environment + 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())); + } 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->status = PROCESS_STATUS_RUNNING; + } + + /* TODO: Close pipes on exit */ + + return process_handle->status; +#else // MS_WINDOWS + pid_t pid; + int stdout_pipe[2]; + int stderr_pipe[2]; + int fd, retval; + ssize_t nbytes; + + 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]; + + static int max_fd = -1; + + /* Assume failure to start */ + memset(process_handle, 0, sizeof(process_handle_t)); + process_handle->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 and stderr 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 process_handle->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)); + return process_handle->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 + max_fd = DEFAULT_MAX_FD; +#endif + + child_state = CHILD_STATE_FORK; + + pid = fork(); + if (0 == pid) { + /* In child */ + + 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_REDIRECT; + + /* Link stdin to /dev/null */ + fd = open("/dev/null", O_RDONLY); /* NOT cloexec, obviously. */ + if (fd != -1) + dup2(fd, STDIN_FILENO); + else + goto error; + + child_state = CHILD_STATE_CLOSEFD; + + close(stderr_pipe[0]); + close(stderr_pipe[1]); + close(stdout_pipe[0]); + close(stdout_pipe[1]); + close(fd); + + /* 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 (envp) + execve(filename, (char *const *) argv, (char*const*)envp); + else + execvp(filename, (char *const *) argv); + + /* 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? */ + + format_helper_exit_status(child_state, errno, hex_errno); + + /* 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); + nbytes = write(STDOUT_FILENO, hex_errno, sizeof(hex_errno)); + + (void) nbytes; + + _exit(255); + /* Never reached, but avoids compiler warning */ + return process_handle->status; + } + + /* In parent */ + + if (-1 == pid) { + log_warn(LD_GENERAL, "Failed to fork child process: %s", strerror(errno)); + close(stdout_pipe[0]); + close(stdout_pipe[1]); + close(stderr_pipe[0]); + close(stderr_pipe[1]); + return process_handle->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->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)); + } + + process_handle->status = PROCESS_STATUS_RUNNING; + /* Set stdout/stderr pipes to be non-blocking */ + fcntl(process_handle->stdout_pipe, F_SETFL, O_NONBLOCK); + fcntl(process_handle->stderr_pipe, F_SETFL, O_NONBLOCK); + /* 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"); + + return process_handle->status; +#endif // MS_WINDOWS +} + +/** 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(const process_handle_t process_handle, + int block, int *exit_code) +{ +#ifdef MS_WINDOWS + 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 + int stat_loc; + int retval; + + retval = waitpid(process_handle.pid, &stat_loc, block?0:WNOHANG); + 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", process_handle.pid, + strerror(errno)); + return PROCESS_EXIT_ERROR; + } + + if (!WIFEXITED(stat_loc)) { + log_warn(LD_GENERAL, "Process %d did not exit normally", + process_handle.pid); + return PROCESS_EXIT_ERROR; + } + + if (exit_code != NULL) + *exit_code = WEXITSTATUS(stat_loc); +#endif // MS_WINDOWS + + return PROCESS_EXIT_EXITED; +} + +#ifdef MS_WINDOWS +/** 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_T_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 +/** Read from a handle <b>h</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(FILE *h, char *buf, size_t count, + const process_handle_t *process, + int *eof) +{ + size_t numread = 0; + char *retval; + + if (eof) + *eof = 0; + + if (count > SIZE_T_CEILING || count > SSIZE_T_MAX) + return -1; + + while (numread != count) { + /* Use fgets because that is what we use in log_from_pipe() */ + retval = fgets(buf+numread, (int)(count-numread), h); + if (NULL == retval) { + if (feof(h)) { + log_debug(LD_GENERAL, "fgets() reached end of file"); + fclose(h); + if (eof) + *eof = 1; + break; + } else { + if (EAGAIN == errno) { + if (process) + continue; + else + break; + } else { + log_warn(LD_GENERAL, "fgets() from handle failed: %s", + strerror(errno)); + fclose(h); + return -1; + } + } + } + tor_assert(retval != NULL); + tor_assert(strlen(retval) + numread <= count); + numread += strlen(retval); + } + + log_debug(LD_GENERAL, "fgets() read %d bytes from handle", (int)numread); + return (ssize_t)numread; +} +#endif + +/** 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 MS_WINDOWS + return tor_read_all_handle(process_handle->stdout_pipe, buf, count, + process_handle); +#else + return tor_read_all_handle(process_handle->stdout_handle, buf, count, + process_handle, NULL); +#endif +} + +/** 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 MS_WINDOWS + return tor_read_all_handle(process_handle->stderr_pipe, buf, count, + process_handle); +#else + return tor_read_all_handle(process_handle->stderr_handle, buf, count, + process_handle, NULL); +#endif +} + +/** 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 MS_WINDOWS +/** Read from stream, and send lines to log at the specified log level. + * Returns -1 if there is a error reading, and 0 otherwise. + * If the generated stream is flushed more often than on new lines, or + * a read exceeds 256 bytes, lines will be truncated. This should be fixed, + * along with the corresponding problem on *nix (see bug #2045). + */ +static int +log_from_handle(HANDLE *pipe, int severity) +{ + char buf[256]; + int pos; + smartlist_t *lines; + + pos = tor_read_all_handle(pipe, buf, sizeof(buf) - 1, NULL); + if (pos < 0) { + /* Error */ + log_warn(LD_GENERAL, "Failed to read data from subprocess"); + return -1; + } + + if (0 == pos) { + /* There's nothing to read (process is busy or has exited) */ + log_debug(LD_GENERAL, "Subprocess had nothing to say"); + return 0; + } + + /* End with a null even if there isn't a \r\n at the end */ + /* TODO: What if this is a partial line? */ + buf[pos] = '\0'; + log_debug(LD_GENERAL, "Subprocess had %d bytes to say", pos); + + /* Split up the buffer */ + lines = smartlist_create(); + tor_split_lines(lines, buf, pos); + + /* Log each line */ + SMARTLIST_FOREACH(lines, char *, line, + { + log_fn(severity, LD_GENERAL, "Port forwarding helper says: %s", line); + }); + smartlist_free(lines); + + return 0; +} + +#else + +/** Read from stream, and send lines to log at the specified log level. + * Returns 1 if stream is closed normally, -1 if there is a error reading, and + * 0 otherwise. Handles lines from tor-fw-helper and + * tor_spawn_background() specially. + */ +static int +log_from_pipe(FILE *stream, int severity, const char *executable, + int *child_status) +{ + char buf[256]; + enum stream_status r; + + for (;;) { + r = get_string_from_pipe(stream, buf, sizeof(buf) - 1); + + if (r == IO_STREAM_CLOSED) { + fclose(stream); + return 1; + } else if (r == IO_STREAM_EAGAIN) { + return 0; + } else if (r == IO_STREAM_TERM) { + fclose(stream); + return -1; + } + + tor_assert(r == IO_STREAM_OKAY); + + /* Check if buf starts with SPAWN_ERROR_MESSAGE */ + if (strcmpstart(buf, SPAWN_ERROR_MESSAGE) == 0) { + /* Parse error message */ + int retval, child_state, saved_errno; + retval = tor_sscanf(buf, SPAWN_ERROR_MESSAGE "%x/%x", + &child_state, &saved_errno); + if (retval == 2) { + 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 a + warning */ + log_warn(LD_GENERAL, + "Unexpected message from port forwarding helper \"%s\": %s", + executable, buf); + } + } else { + log_fn(severity, LD_GENERAL, "Port forwarding helper says: %s", buf); + } + } + + /* We should never get here */ + return -1; +} +#endif + +/** Reads from <b>stream</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(FILE *stream, char *buf_out, size_t count) +{ + char *retval; + size_t len; + + tor_assert(count <= INT_MAX); + + retval = fgets(buf_out, (int)count, stream); + + if (!retval) { + if (feof(stream)) { + /* Program has closed stream (probably it exited) */ + /* TODO: check error */ + return IO_STREAM_CLOSED; + } else { + if (EAGAIN == errno) { + /* Nothing more to read, try again next time */ + return IO_STREAM_EAGAIN; + } else { + /* There was a problem, abandon this child process */ + return IO_STREAM_TERM; + } + } + } else { + len = strlen(buf_out); + tor_assert(len>0); + + if (buf_out[len - 1] == '\n') { + /* Remove the trailing newline */ + buf_out[len - 1] = '\0'; + } else { + /* No newline; check whether we overflowed the buffer */ + if (!feof(stream)) + log_info(LD_GENERAL, + "Line from stream was truncated: %s", buf_out); + /* TODO: What to do with this error? */ + } + + return IO_STREAM_OKAY; + } + + /* We should never get here */ + return IO_STREAM_TERM; +} + +void +tor_check_port_forwarding(const char *filename, int dir_port, int or_port, + time_t now) +{ +/* When fw-helper succeeds, how long do we wait until running it again */ +#define TIME_TO_EXEC_FWHELPER_SUCCESS 300 +/* When fw-helper failed to start, how long do we wait until running it again + */ +#define TIME_TO_EXEC_FWHELPER_FAIL 60 + + /* Static variables are initialized to zero, so child_handle.status=0 + * which corresponds to it not running on startup */ + static process_handle_t child_handle; + + static time_t time_to_run_helper = 0; + int stdout_status, stderr_status, retval; + const char *argv[10]; + char s_dirport[6], s_orport[6]; + + tor_assert(filename); + + /* Set up command line for tor-fw-helper */ + snprintf(s_dirport, sizeof s_dirport, "%d", dir_port); + snprintf(s_orport, sizeof s_orport, "%d", or_port); + + /* TODO: Allow different internal and external ports */ + argv[0] = filename; + argv[1] = "--internal-or-port"; + argv[2] = s_orport; + argv[3] = "--external-or-port"; + argv[4] = s_orport; + argv[5] = "--internal-dir-port"; + argv[6] = s_dirport; + argv[7] = "--external-dir-port"; + argv[8] = s_dirport; + argv[9] = NULL; + + /* Start the child, if it is not already running */ + if (child_handle.status != PROCESS_STATUS_RUNNING && + time_to_run_helper < now) { + /* Assume tor-fw-helper will succeed, start it later*/ + time_to_run_helper = now + TIME_TO_EXEC_FWHELPER_SUCCESS; + +#ifdef MS_WINDOWS + /* Passing NULL as lpApplicationName makes Windows search for the .exe */ + tor_spawn_background(NULL, argv, NULL, &child_handle); +#else + tor_spawn_background(filename, argv, NULL, &child_handle); +#endif + if (PROCESS_STATUS_ERROR == child_handle.status) { + log_warn(LD_GENERAL, "Failed to start port forwarding helper %s", + filename); + time_to_run_helper = now + TIME_TO_EXEC_FWHELPER_FAIL; + return; + } +#ifdef MS_WINDOWS + log_info(LD_GENERAL, + "Started port forwarding helper (%s)", filename); +#else + log_info(LD_GENERAL, + "Started port forwarding helper (%s) with pid %d", filename, + child_handle.pid); +#endif + } + + /* If child is running, read from its stdout and stderr) */ + if (PROCESS_STATUS_RUNNING == child_handle.status) { + /* Read from stdout/stderr and log result */ + retval = 0; +#ifdef MS_WINDOWS + stdout_status = log_from_handle(child_handle.stdout_pipe, LOG_INFO); + stderr_status = log_from_handle(child_handle.stderr_pipe, LOG_WARN); + /* If we got this far (on Windows), the process started */ + retval = 0; +#else + stdout_status = log_from_pipe(child_handle.stdout_handle, + LOG_INFO, filename, &retval); + stderr_status = log_from_pipe(child_handle.stderr_handle, + LOG_WARN, filename, &retval); +#endif + if (retval) { + /* There was a problem in the child process */ + time_to_run_helper = now + TIME_TO_EXEC_FWHELPER_FAIL; + } + + /* Combine the two statuses in order of severity */ + if (-1 == stdout_status || -1 == stderr_status) + /* There was a failure */ + retval = -1; +#ifdef MS_WINDOWS + else if (tor_get_exit_code(child_handle, 0, NULL) != + PROCESS_EXIT_RUNNING) { + /* process has exited or there was an error */ + /* TODO: Do something with the process return value */ + /* TODO: What if the process output something since + * between log_from_handle and tor_get_exit_code? */ + retval = 1; + } +#else + else if (1 == stdout_status || 1 == stderr_status) + /* stdout or stderr was closed, the process probably + * exited. It will be reaped by waitpid() in main.c */ + /* TODO: Do something with the process return value */ + retval = 1; +#endif + else + /* Both are fine */ + retval = 0; + + /* If either pipe indicates a failure, act on it */ + if (0 != retval) { + if (1 == retval) { + log_info(LD_GENERAL, "Port forwarding helper terminated"); + child_handle.status = PROCESS_STATUS_NOTRUNNING; + } else { + log_warn(LD_GENERAL, "Failed to read from port forwarding helper"); + child_handle.status = PROCESS_STATUS_ERROR; + } + + /* TODO: The child might not actually be finished (maybe it failed or + closed stdout/stderr), so maybe we shouldn't start another? */ + } + } +} + |