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Diffstat (limited to 'src/lib/process/process.c')
| -rw-r--r-- | src/lib/process/process.c | 798 |
1 files changed, 798 insertions, 0 deletions
diff --git a/src/lib/process/process.c b/src/lib/process/process.c new file mode 100644 index 0000000000..12c1f9a772 --- /dev/null +++ b/src/lib/process/process.c @@ -0,0 +1,798 @@ +/* Copyright (c) 2003, Roger Dingledine + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2020, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file process.c + * \brief Module for working with other processes. + **/ + +#define PROCESS_PRIVATE +#include "lib/buf/buffers.h" +#include "lib/net/buffers_net.h" +#include "lib/container/smartlist.h" +#include "lib/log/log.h" +#include "lib/log/util_bug.h" +#include "lib/process/process.h" +#include "lib/process/process_unix.h" +#include "lib/process/process_win32.h" +#include "lib/process/env.h" + +#ifdef HAVE_STDDEF_H +#include <stddef.h> +#endif + +/** A list of all <b>process_t</b> instances currently allocated. */ +static smartlist_t *processes; + +/** + * Boolean. If true, then Tor may call execve or CreateProcess via + * tor_spawn_background. + **/ +static int may_spawn_background_process = 1; + +/** Structure to represent a child process. */ +struct process_t { + /** Process status. */ + process_status_t status; + + /** Which protocol is the process using? */ + process_protocol_t protocol; + + /** Which function to call when we have data ready from stdout? */ + process_read_callback_t stdout_read_callback; + + /** Which function to call when we have data ready from stderr? */ + process_read_callback_t stderr_read_callback; + + /** Which function call when our process terminated? */ + process_exit_callback_t exit_callback; + + /** Our exit code when the process have terminated. */ + process_exit_code_t exit_code; + + /** Name of the command we want to execute (for example: /bin/ls). */ + char *command; + + /** The arguments used for the new process. The format here is one argument + * per element of the smartlist_t. On Windows these arguments are combined + * together using the <b>tor_join_win_cmdline</b> function. On Unix the + * process name (argv[0]) and the trailing NULL is added automatically before + * the process is executed. */ + smartlist_t *arguments; + + /** The environment used for the new process. */ + smartlist_t *environment; + + /** Buffer to store data from stdout when it is read. */ + buf_t *stdout_buffer; + + /** Buffer to store data from stderr when it is read. */ + buf_t *stderr_buffer; + + /** Buffer to store data to stdin before it is written. */ + buf_t *stdin_buffer; + + /** Do we need to store some custom data with the process? */ + void *data; + +#ifndef _WIN32 + /** Our Unix process handle. */ + process_unix_t *unix_process; +#else + /** Our Win32 process handle. */ + process_win32_t *win32_process; +#endif /* !defined(_WIN32) */ +}; + +/** Convert a given process status in <b>status</b> to its string + * representation. */ +const char * +process_status_to_string(process_status_t status) +{ + switch (status) { + case PROCESS_STATUS_NOT_RUNNING: + return "not running"; + case PROCESS_STATUS_RUNNING: + return "running"; + case PROCESS_STATUS_ERROR: + return "error"; + } + + /* LCOV_EXCL_START */ + tor_assert_unreached(); + return NULL; + /* LCOV_EXCL_STOP */ +} + +/** Convert a given process protocol in <b>protocol</b> to its string + * representation. */ +const char * +process_protocol_to_string(process_protocol_t protocol) +{ + switch (protocol) { + case PROCESS_PROTOCOL_LINE: + return "Line"; + case PROCESS_PROTOCOL_RAW: + return "Raw"; + } + + /* LCOV_EXCL_START */ + tor_assert_unreached(); + return NULL; + /* LCOV_EXCL_STOP */ +} + +/** + * 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; +} + +/** Initialize the Process subsystem. This function initializes the Process + * subsystem's global state. For cleaning up, <b>process_free_all()</b> should + * be called. */ +void +process_init(void) +{ + processes = smartlist_new(); + +#ifdef _WIN32 + process_win32_init(); +#endif +} + +/** Free up all resources that is handled by the Process subsystem. Note that + * this call does not terminate already running processes. */ +void +process_free_all(void) +{ +#ifdef _WIN32 + process_win32_deinit(); +#endif + + SMARTLIST_FOREACH(processes, process_t *, x, process_free(x)); + smartlist_free(processes); +} + +/** Get a list of all processes. This function returns a smartlist of + * <b>process_t</b> containing all the currently allocated processes. */ +const smartlist_t * +process_get_all_processes(void) +{ + return processes; +} + +/** Allocate and initialize a new process. This function returns a newly + * allocated and initialized process data, which can be used to configure and + * later run a subprocess of Tor. Use the various <b>process_set_*()</b> + * methods to configure it and run the process using <b>process_exec()</b>. Use + * <b>command</b> to specify the path to the command to run. You can either + * specify an absolute path to the command or relative where Tor will use the + * underlying operating system's functionality for finding the command to run. + * */ +process_t * +process_new(const char *command) +{ + tor_assert(command); + + process_t *process; + process = tor_malloc_zero(sizeof(process_t)); + + /* Set our command. */ + process->command = tor_strdup(command); + + /* By default we are not running. */ + process->status = PROCESS_STATUS_NOT_RUNNING; + + /* Prepare process environment. */ + process->arguments = smartlist_new(); + process->environment = smartlist_new(); + + /* Prepare the buffers. */ + process->stdout_buffer = buf_new(); + process->stderr_buffer = buf_new(); + process->stdin_buffer = buf_new(); + +#ifndef _WIN32 + /* Prepare our Unix process handle. */ + process->unix_process = process_unix_new(); +#else + /* Prepare our Win32 process handle. */ + process->win32_process = process_win32_new(); +#endif /* !defined(_WIN32) */ + + smartlist_add(processes, process); + + return process; +} + +/** Deallocate the given process in <b>process</b>. */ +void +process_free_(process_t *process) +{ + if (! process) + return; + + /* Cleanup parameters. */ + tor_free(process->command); + + /* Cleanup arguments and environment. */ + SMARTLIST_FOREACH(process->arguments, char *, x, tor_free(x)); + smartlist_free(process->arguments); + + SMARTLIST_FOREACH(process->environment, char *, x, tor_free(x)); + smartlist_free(process->environment); + + /* Cleanup the buffers. */ + buf_free(process->stdout_buffer); + buf_free(process->stderr_buffer); + buf_free(process->stdin_buffer); + +#ifndef _WIN32 + /* Cleanup our Unix process handle. */ + process_unix_free(process->unix_process); +#else + /* Cleanup our Win32 process handle. */ + process_win32_free(process->win32_process); +#endif /* !defined(_WIN32) */ + + smartlist_remove(processes, process); + + tor_free(process); +} + +/** Execute the given process. This function executes the given process as a + * subprocess of Tor. Returns <b>PROCESS_STATUS_RUNNING</b> upon success. */ +process_status_t +process_exec(process_t *process) +{ + tor_assert(process); + + if (BUG(may_spawn_background_process == 0)) + return PROCESS_STATUS_ERROR; + + process_status_t status = PROCESS_STATUS_NOT_RUNNING; + + log_info(LD_PROCESS, "Starting new process: %s", process->command); + +#ifndef _WIN32 + status = process_unix_exec(process); +#else + status = process_win32_exec(process); +#endif + + /* Update our state. */ + process_set_status(process, status); + + if (status != PROCESS_STATUS_RUNNING) { + log_warn(LD_PROCESS, "Failed to start process: %s", + process_get_command(process)); + } + + return status; +} + +/** Terminate the given process. Returns true on success, + * otherwise false. */ +bool +process_terminate(process_t *process) +{ + tor_assert(process); + + /* Terminating a non-running process isn't going to work. */ + if (process_get_status(process) != PROCESS_STATUS_RUNNING) + return false; + + log_debug(LD_PROCESS, "Terminating process"); + +#ifndef _WIN32 + return process_unix_terminate(process); +#else + return process_win32_terminate(process); +#endif +} + +/** Returns the unique process identifier for the given <b>process</b>. */ +process_pid_t +process_get_pid(process_t *process) +{ + tor_assert(process); + +#ifndef _WIN32 + return process_unix_get_pid(process); +#else + return process_win32_get_pid(process); +#endif +} + +/** Set the callback function for output from the child process's standard out + * handle. This function sets the callback function which is called every time + * the child process have written output to its standard out file handle. + * + * Use <b>process_set_protocol(process, PROCESS_PROTOCOL_LINE)</b> if you want + * the callback to only contain complete "\n" or "\r\n" terminated lines. */ +void +process_set_stdout_read_callback(process_t *process, + process_read_callback_t callback) +{ + tor_assert(process); + process->stdout_read_callback = callback; +} + +/** Set the callback function for output from the child process's standard + * error handle. This function sets the callback function which is called + * every time the child process have written output to its standard error file + * handle. + * + * Use <b>process_set_protocol(process, PROCESS_PROTOCOL_LINE)</b> if you want + * the callback to only contain complete "\n" or "\r\n" terminated lines. */ +void +process_set_stderr_read_callback(process_t *process, + process_read_callback_t callback) +{ + tor_assert(process); + process->stderr_read_callback = callback; +} + +/** Set the callback function for process exit notification. The + * <b>callback</b> function will be called every time your child process have + * terminated. */ +void +process_set_exit_callback(process_t *process, + process_exit_callback_t callback) +{ + tor_assert(process); + process->exit_callback = callback; +} + +/** Get the current command of the given process. */ +const char * +process_get_command(const process_t *process) +{ + tor_assert(process); + return process->command; +} + +void +process_set_protocol(process_t *process, process_protocol_t protocol) +{ + tor_assert(process); + process->protocol = protocol; +} + +/** Get the currently used protocol of the given process. */ +process_protocol_t +process_get_protocol(const process_t *process) +{ + tor_assert(process); + return process->protocol; +} + +/** Set opague pointer to data. This function allows you to store a pointer to + * your own data in the given process. Use <b>process_get_data()</b> in the + * various callback functions to retrieve the data again. + * + * Note that the given process does NOT take ownership of the data and you are + * responsible for freeing up any resources allocated by the given data. + * */ +void +process_set_data(process_t *process, void *data) +{ + tor_assert(process); + process->data = data; +} + +/** Get the opaque pointer to callback data from the given process. This + * function allows you get the data you stored with <b>process_set_data()</b> + * in the different callback functions. */ +void * +process_get_data(const process_t *process) +{ + tor_assert(process); + return process->data; +} + +/** Set the status of a given process. */ +void +process_set_status(process_t *process, process_status_t status) +{ + tor_assert(process); + process->status = status; +} + +/** Get the status of the given process. */ +process_status_t +process_get_status(const process_t *process) +{ + tor_assert(process); + return process->status; +} + +/** Append an argument to the list of arguments in the given process. */ +void +process_append_argument(process_t *process, const char *argument) +{ + tor_assert(process); + tor_assert(argument); + + smartlist_add(process->arguments, tor_strdup(argument)); +} + +/** Returns a list of arguments (excluding the command itself) from the + * given process. */ +const smartlist_t * +process_get_arguments(const process_t *process) +{ + tor_assert(process); + return process->arguments; +} + +/** Returns a newly allocated Unix style argument vector. Use <b>tor_free()</b> + * to deallocate it after use. */ +char ** +process_get_argv(const process_t *process) +{ + tor_assert(process); + + /** Generate a Unix style process argument vector from our process's + * arguments smartlist_t. */ + char **argv = NULL; + + char *filename = process->command; + const smartlist_t *arguments = process->arguments; + const size_t size = smartlist_len(arguments); + + /* Make space for the process filename as argv[0] and a trailing NULL. */ + argv = tor_malloc_zero(sizeof(char *) * (size + 2)); + + /* Set our filename as first argument. */ + argv[0] = filename; + + /* Put in the rest of the values from arguments. */ + SMARTLIST_FOREACH_BEGIN(arguments, char *, arg_val) { + tor_assert(arg_val != NULL); + + argv[arg_val_sl_idx + 1] = arg_val; + } SMARTLIST_FOREACH_END(arg_val); + + return argv; +} + +/** This function clears the internal environment and copies over every string + * from <b>env</b> as the new environment. */ +void +process_reset_environment(process_t *process, const smartlist_t *env) +{ + tor_assert(process); + tor_assert(env); + + /* Cleanup old environment. */ + SMARTLIST_FOREACH(process->environment, char *, x, tor_free(x)); + smartlist_free(process->environment); + process->environment = smartlist_new(); + + SMARTLIST_FOREACH(env, char *, x, + smartlist_add(process->environment, tor_strdup(x))); +} + +/** Set the given <b>key</b>/<b>value</b> pair as environment variable in the + * given process. */ +void +process_set_environment(process_t *process, + const char *key, + const char *value) +{ + tor_assert(process); + tor_assert(key); + tor_assert(value); + + smartlist_add_asprintf(process->environment, "%s=%s", key, value); +} + +/** Returns a newly allocated <b>process_environment_t</b> containing the + * environment variables for the given process. */ +process_environment_t * +process_get_environment(const process_t *process) +{ + tor_assert(process); + return process_environment_make(process->environment); +} + +#ifndef _WIN32 +/** Get the internal handle for the Unix backend. */ +process_unix_t * +process_get_unix_process(const process_t *process) +{ + tor_assert(process); + tor_assert(process->unix_process); + return process->unix_process; +} +#else /* defined(_WIN32) */ +/** Get the internal handle for Windows backend. */ +process_win32_t * +process_get_win32_process(const process_t *process) +{ + tor_assert(process); + tor_assert(process->win32_process); + return process->win32_process; +} +#endif /* !defined(_WIN32) */ + +/** Write <b>size</b> bytes of <b>data</b> to the given process's standard + * input. */ +void +process_write(process_t *process, + const uint8_t *data, size_t size) +{ + tor_assert(process); + tor_assert(data); + + buf_add(process->stdin_buffer, (char *)data, size); + process_write_stdin(process, process->stdin_buffer); +} + +/** As tor_vsnprintf(), but write the data to the given process's standard + * input. */ +void +process_vprintf(process_t *process, + const char *format, va_list args) +{ + tor_assert(process); + tor_assert(format); + + int size; + char *data; + + size = tor_vasprintf(&data, format, args); + tor_assert(data != NULL); + process_write(process, (uint8_t *)data, size); + tor_free(data); +} + +/** As tor_snprintf(), but write the data to the given process's standard + * input. */ +void +process_printf(process_t *process, + const char *format, ...) +{ + tor_assert(process); + tor_assert(format); + + va_list ap; + va_start(ap, format); + process_vprintf(process, format, ap); + va_end(ap); +} + +/** This function is called by the Process backend when a given process have + * data that is ready to be read from the child process's standard output + * handle. */ +void +process_notify_event_stdout(process_t *process) +{ + tor_assert(process); + + int ret; + ret = process_read_stdout(process, process->stdout_buffer); + + if (ret > 0) + process_read_data(process, + process->stdout_buffer, + process->stdout_read_callback); +} + +/** This function is called by the Process backend when a given process have + * data that is ready to be read from the child process's standard error + * handle. */ +void +process_notify_event_stderr(process_t *process) +{ + tor_assert(process); + + int ret; + ret = process_read_stderr(process, process->stderr_buffer); + + if (ret > 0) + process_read_data(process, + process->stderr_buffer, + process->stderr_read_callback); +} + +/** This function is called by the Process backend when a given process is + * allowed to begin writing data to the standard input of the child process. */ +void +process_notify_event_stdin(process_t *process) +{ + tor_assert(process); + + process_write_stdin(process, process->stdin_buffer); +} + +/** This function is called by the Process backend when a given process have + * terminated. The exit status code is passed in <b>exit_code</b>. We mark the + * process as no longer running and calls the <b>exit_callback</b> with + * information about the process termination. The given <b>process</b> is + * free'd iff the exit_callback returns true. */ +void +process_notify_event_exit(process_t *process, process_exit_code_t exit_code) +{ + tor_assert(process); + + log_debug(LD_PROCESS, + "Process terminated with exit code: %"PRIu64, exit_code); + + /* Update our state. */ + process_set_status(process, PROCESS_STATUS_NOT_RUNNING); + process->exit_code = exit_code; + + /* Call our exit callback, if it exists. */ + bool free_process_handle = false; + + /* The exit callback will tell us if we should process_free() our handle. */ + if (process->exit_callback) + free_process_handle = process->exit_callback(process, exit_code); + + if (free_process_handle) + process_free(process); +} + +/** This function is called whenever the Process backend have notified us that + * there is data to be read from its standard out handle. Returns the number of + * bytes that have been put into the given buffer. */ +MOCK_IMPL(STATIC int, process_read_stdout, (process_t *process, buf_t *buffer)) +{ + tor_assert(process); + tor_assert(buffer); + +#ifndef _WIN32 + return process_unix_read_stdout(process, buffer); +#else + return process_win32_read_stdout(process, buffer); +#endif +} + +/** This function is called whenever the Process backend have notified us that + * there is data to be read from its standard error handle. Returns the number + * of bytes that have been put into the given buffer. */ +MOCK_IMPL(STATIC int, process_read_stderr, (process_t *process, buf_t *buffer)) +{ + tor_assert(process); + tor_assert(buffer); + +#ifndef _WIN32 + return process_unix_read_stderr(process, buffer); +#else + return process_win32_read_stderr(process, buffer); +#endif +} + +/** This function calls the backend function for the given process whenever + * there is data to be written to the backends' file handles. */ +MOCK_IMPL(STATIC void, process_write_stdin, + (process_t *process, buf_t *buffer)) +{ + tor_assert(process); + tor_assert(buffer); + +#ifndef _WIN32 + process_unix_write(process, buffer); +#else + process_win32_write(process, buffer); +#endif +} + +/** This function calls the protocol handlers based on the value of + * <b>process_get_protocol(process)</b>. Currently we call + * <b>process_read_buffer()</b> for <b>PROCESS_PROTOCOL_RAW</b> and + * <b>process_read_lines()</b> for <b>PROCESS_PROTOCOL_LINE</b>. */ +STATIC void +process_read_data(process_t *process, + buf_t *buffer, + process_read_callback_t callback) +{ + tor_assert(process); + tor_assert(buffer); + + switch (process_get_protocol(process)) { + case PROCESS_PROTOCOL_RAW: + process_read_buffer(process, buffer, callback); + break; + case PROCESS_PROTOCOL_LINE: + process_read_lines(process, buffer, callback); + break; + default: + /* LCOV_EXCL_START */ + tor_assert_unreached(); + return; + /* LCOV_EXCL_STOP */ + } +} + +/** This function takes the content of the given <b>buffer</b> and passes it to + * the given <b>callback</b> function, but ensures that an additional zero byte + * is added to the end of the data such that the given callback implementation + * can threat the content as a ASCIIZ string. */ +STATIC void +process_read_buffer(process_t *process, + buf_t *buffer, + process_read_callback_t callback) +{ + tor_assert(process); + tor_assert(buffer); + + const size_t size = buf_datalen(buffer); + + /* We allocate an extra byte for the zero byte in the end. */ + char *data = tor_malloc_zero(size + 1); + + buf_get_bytes(buffer, data, size); + log_debug(LD_PROCESS, "Read data from process"); + + if (callback) + callback(process, data, size); + + tor_free(data); +} + +/** This function tries to extract complete lines from the given <b>buffer</b> + * and calls the given <b>callback</b> function whenever it has a complete + * line. Before calling <b>callback</b> we remove the trailing "\n" or "\r\n" + * from the line. If we are unable to extract a complete line we leave the data + * in the buffer for next call. */ +STATIC void +process_read_lines(process_t *process, + buf_t *buffer, + process_read_callback_t callback) +{ + tor_assert(process); + tor_assert(buffer); + + const size_t size = buf_datalen(buffer) + 1; + size_t line_size = 0; + char *data = tor_malloc_zero(size); + int ret; + + while (true) { + line_size = size; + ret = buf_get_line(buffer, data, &line_size); + + /* A complete line should always be smaller than the size of our + * buffer. */ + tor_assert(ret != -1); + + /* Remove \n from the end of the line. */ + if (line_size >= 1 && data[line_size - 1] == '\n') { + data[line_size - 1] = '\0'; + --line_size; + } + + /* Remove \r from the end of the line. */ + if (line_size >= 1 && data[line_size - 1] == '\r') { + data[line_size - 1] = '\0'; + --line_size; + } + + if (ret == 1) { + log_debug(LD_PROCESS, "Read line from process: \"%s\"", data); + + if (callback) + callback(process, data, line_size); + + /* We have read a whole line, let's see if there is more lines to read. + * */ + continue; + } + + /* No complete line for us to read. We are done for now. */ + tor_assert_nonfatal(ret == 0); + break; + } + + tor_free(data); +} |