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Diffstat (limited to 'glib/glib/gspawn.c')
| -rw-r--r-- | glib/glib/gspawn.c | 1730 |
1 files changed, 1730 insertions, 0 deletions
diff --git a/glib/glib/gspawn.c b/glib/glib/gspawn.c new file mode 100644 index 0000000..e0a19ae --- /dev/null +++ b/glib/glib/gspawn.c @@ -0,0 +1,1730 @@ +/* gspawn.c - Process launching + * + * Copyright 2000 Red Hat, Inc. + * g_execvpe implementation based on GNU libc execvp: + * Copyright 1991, 92, 95, 96, 97, 98, 99 Free Software Foundation, Inc. + * + * GLib is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or (at your option) any later version. + * + * GLib is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with GLib; see the file COPYING.LIB. If not, write + * to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +#include "config.h" + +#include <sys/time.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> +#include <signal.h> +#include <string.h> +#include <stdlib.h> /* for fdwalk */ +#include <dirent.h> + +#ifdef HAVE_SYS_SELECT_H +#include <sys/select.h> +#endif /* HAVE_SYS_SELECT_H */ + +#ifdef HAVE_SYS_RESOURCE_H +#include <sys/resource.h> +#endif /* HAVE_SYS_RESOURCE_H */ + +#include "gspawn.h" + +#include "genviron.h" +#include "gmem.h" +#include "gshell.h" +#include "gstring.h" +#include "gstrfuncs.h" +#include "gtestutils.h" +#include "gutils.h" +#include "glibintl.h" + + +/** + * SECTION:spawn + * @Short_description: process launching + * @Title: Spawning Processes + */ + + + +static gint g_execute (const gchar *file, + gchar **argv, + gchar **envp, + gboolean search_path); + +static gboolean make_pipe (gint p[2], + GError **error); +static gboolean fork_exec_with_pipes (gboolean intermediate_child, + const gchar *working_directory, + gchar **argv, + gchar **envp, + gboolean close_descriptors, + gboolean search_path, + gboolean stdout_to_null, + gboolean stderr_to_null, + gboolean child_inherits_stdin, + gboolean file_and_argv_zero, + GSpawnChildSetupFunc child_setup, + gpointer user_data, + GPid *child_pid, + gint *standard_input, + gint *standard_output, + gint *standard_error, + GError **error); + +GQuark +g_spawn_error_quark (void) +{ + return g_quark_from_static_string ("g-exec-error-quark"); +} + +/** + * g_spawn_async: + * @working_directory: (allow-none): child's current working directory, or %NULL to inherit parent's + * @argv: (array zero-terminated=1): child's argument vector + * @envp: (array zero-terminated=1) (allow-none): child's environment, or %NULL to inherit parent's + * @flags: flags from #GSpawnFlags + * @child_setup: (scope async) (allow-none): function to run in the child just before exec() + * @user_data: (closure): user data for @child_setup + * @child_pid: (out) (allow-none): return location for child process reference, or %NULL + * @error: return location for error + * + * See g_spawn_async_with_pipes() for a full description; this function + * simply calls the g_spawn_async_with_pipes() without any pipes. + * + * You should call g_spawn_close_pid() on the returned child process + * reference when you don't need it any more. + * + * <note><para> + * If you are writing a GTK+ application, and the program you + * are spawning is a graphical application, too, then you may + * want to use gdk_spawn_on_screen() instead to ensure that + * the spawned program opens its windows on the right screen. + * </para></note> + * + * <note><para> Note that the returned @child_pid on Windows is a + * handle to the child process and not its identifier. Process handles + * and process identifiers are different concepts on Windows. + * </para></note> + * + * Return value: %TRUE on success, %FALSE if error is set + **/ +gboolean +g_spawn_async (const gchar *working_directory, + gchar **argv, + gchar **envp, + GSpawnFlags flags, + GSpawnChildSetupFunc child_setup, + gpointer user_data, + GPid *child_pid, + GError **error) +{ + g_return_val_if_fail (argv != NULL, FALSE); + + return g_spawn_async_with_pipes (working_directory, + argv, envp, + flags, + child_setup, + user_data, + child_pid, + NULL, NULL, NULL, + error); +} + +/* Avoids a danger in threaded situations (calling close() + * on a file descriptor twice, and another thread has + * re-opened it since the first close) + */ +static gint +close_and_invalidate (gint *fd) +{ + gint ret; + + if (*fd < 0) + return -1; + else + { + again: + ret = close (*fd); + if (ret == -1 && errno == EINTR) + goto again; + *fd = -1; + } + + return ret; +} + +/* Some versions of OS X define READ_OK in public headers */ +#undef READ_OK + +typedef enum +{ + READ_FAILED = 0, /* FALSE */ + READ_OK, + READ_EOF +} ReadResult; + +static ReadResult +read_data (GString *str, + gint fd, + GError **error) +{ + gssize bytes; + gchar buf[4096]; + + again: + bytes = read (fd, buf, 4096); + + if (bytes == 0) + return READ_EOF; + else if (bytes > 0) + { + g_string_append_len (str, buf, bytes); + return READ_OK; + } + else if (errno == EINTR) + goto again; + else + { + int errsv = errno; + + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_READ, + _("Failed to read data from child process (%s)"), + g_strerror (errsv)); + + return READ_FAILED; + } +} + +/** + * g_spawn_sync: + * @working_directory: (allow-none): child's current working directory, or %NULL to inherit parent's + * @argv: (array zero-terminated=1): child's argument vector + * @envp: (array zero-terminated=1) (allow-none): child's environment, or %NULL to inherit parent's + * @flags: flags from #GSpawnFlags + * @child_setup: (scope async) (allow-none): function to run in the child just before exec() + * @user_data: (closure): user data for @child_setup + * @standard_output: (out) (array zero-terminated=1) (element-type guint8) (allow-none): return location for child output, or %NULL + * @standard_error: (out) (array zero-terminated=1) (element-type guint8) (allow-none): return location for child error messages, or %NULL + * @exit_status: (out) (allow-none): return location for child exit status, as returned by waitpid(), or %NULL + * @error: return location for error, or %NULL + * + * Executes a child synchronously (waits for the child to exit before returning). + * All output from the child is stored in @standard_output and @standard_error, + * if those parameters are non-%NULL. Note that you must set the + * %G_SPAWN_STDOUT_TO_DEV_NULL and %G_SPAWN_STDERR_TO_DEV_NULL flags when + * passing %NULL for @standard_output and @standard_error. + * If @exit_status is non-%NULL, the exit status of the child is stored + * there as it would be returned by waitpid(); standard UNIX macros such + * as WIFEXITED() and WEXITSTATUS() must be used to evaluate the exit status. + * Note that this function call waitpid() even if @exit_status is %NULL, and + * does not accept the %G_SPAWN_DO_NOT_REAP_CHILD flag. + * If an error occurs, no data is returned in @standard_output, + * @standard_error, or @exit_status. + * + * This function calls g_spawn_async_with_pipes() internally; see that + * function for full details on the other parameters and details on + * how these functions work on Windows. + * + * Return value: %TRUE on success, %FALSE if an error was set. + **/ +gboolean +g_spawn_sync (const gchar *working_directory, + gchar **argv, + gchar **envp, + GSpawnFlags flags, + GSpawnChildSetupFunc child_setup, + gpointer user_data, + gchar **standard_output, + gchar **standard_error, + gint *exit_status, + GError **error) +{ + gint outpipe = -1; + gint errpipe = -1; + GPid pid; + fd_set fds; + gint ret; + GString *outstr = NULL; + GString *errstr = NULL; + gboolean failed; + gint status; + + g_return_val_if_fail (argv != NULL, FALSE); + g_return_val_if_fail (!(flags & G_SPAWN_DO_NOT_REAP_CHILD), FALSE); + g_return_val_if_fail (standard_output == NULL || + !(flags & G_SPAWN_STDOUT_TO_DEV_NULL), FALSE); + g_return_val_if_fail (standard_error == NULL || + !(flags & G_SPAWN_STDERR_TO_DEV_NULL), FALSE); + + /* Just to ensure segfaults if callers try to use + * these when an error is reported. + */ + if (standard_output) + *standard_output = NULL; + + if (standard_error) + *standard_error = NULL; + + if (!fork_exec_with_pipes (FALSE, + working_directory, + argv, + envp, + !(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN), + (flags & G_SPAWN_SEARCH_PATH) != 0, + (flags & G_SPAWN_STDOUT_TO_DEV_NULL) != 0, + (flags & G_SPAWN_STDERR_TO_DEV_NULL) != 0, + (flags & G_SPAWN_CHILD_INHERITS_STDIN) != 0, + (flags & G_SPAWN_FILE_AND_ARGV_ZERO) != 0, + child_setup, + user_data, + &pid, + NULL, + standard_output ? &outpipe : NULL, + standard_error ? &errpipe : NULL, + error)) + return FALSE; + + /* Read data from child. */ + + failed = FALSE; + + if (outpipe >= 0) + { + outstr = g_string_new (NULL); + } + + if (errpipe >= 0) + { + errstr = g_string_new (NULL); + } + + /* Read data until we get EOF on both pipes. */ + while (!failed && + (outpipe >= 0 || + errpipe >= 0)) + { + ret = 0; + + FD_ZERO (&fds); + if (outpipe >= 0) + FD_SET (outpipe, &fds); + if (errpipe >= 0) + FD_SET (errpipe, &fds); + + ret = select (MAX (outpipe, errpipe) + 1, + &fds, + NULL, NULL, + NULL /* no timeout */); + + if (ret < 0) + { + int errsv = errno; + + if (errno == EINTR) + continue; + + failed = TRUE; + + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_READ, + _("Unexpected error in select() reading data from a child process (%s)"), + g_strerror (errsv)); + + break; + } + + if (outpipe >= 0 && FD_ISSET (outpipe, &fds)) + { + switch (read_data (outstr, outpipe, error)) + { + case READ_FAILED: + failed = TRUE; + break; + case READ_EOF: + close_and_invalidate (&outpipe); + outpipe = -1; + break; + default: + break; + } + + if (failed) + break; + } + + if (errpipe >= 0 && FD_ISSET (errpipe, &fds)) + { + switch (read_data (errstr, errpipe, error)) + { + case READ_FAILED: + failed = TRUE; + break; + case READ_EOF: + close_and_invalidate (&errpipe); + errpipe = -1; + break; + default: + break; + } + + if (failed) + break; + } + } + + /* These should only be open still if we had an error. */ + + if (outpipe >= 0) + close_and_invalidate (&outpipe); + if (errpipe >= 0) + close_and_invalidate (&errpipe); + + /* Wait for child to exit, even if we have + * an error pending. + */ + again: + + ret = waitpid (pid, &status, 0); + + if (ret < 0) + { + if (errno == EINTR) + goto again; + else if (errno == ECHILD) + { + if (exit_status) + { + g_warning ("In call to g_spawn_sync(), exit status of a child process was requested but SIGCHLD action was set to SIG_IGN and ECHILD was received by waitpid(), so exit status can't be returned. This is a bug in the program calling g_spawn_sync(); either don't request the exit status, or don't set the SIGCHLD action."); + } + else + { + /* We don't need the exit status. */ + } + } + else + { + if (!failed) /* avoid error pileups */ + { + int errsv = errno; + + failed = TRUE; + + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_READ, + _("Unexpected error in waitpid() (%s)"), + g_strerror (errsv)); + } + } + } + + if (failed) + { + if (outstr) + g_string_free (outstr, TRUE); + if (errstr) + g_string_free (errstr, TRUE); + + return FALSE; + } + else + { + if (exit_status) + *exit_status = status; + + if (standard_output) + *standard_output = g_string_free (outstr, FALSE); + + if (standard_error) + *standard_error = g_string_free (errstr, FALSE); + + return TRUE; + } +} + +/** + * g_spawn_async_with_pipes: + * @working_directory: (allow-none): child's current working directory, or %NULL to inherit parent's, in the GLib file name encoding + * @argv: (array zero-terminated=1): child's argument vector, in the GLib file name encoding + * @envp: (array zero-terminated=1) (allow-none): child's environment, or %NULL to inherit parent's, in the GLib file name encoding + * @flags: flags from #GSpawnFlags + * @child_setup: (scope async) (allow-none): function to run in the child just before exec() + * @user_data: (closure): user data for @child_setup + * @child_pid: (out) (allow-none): return location for child process ID, or %NULL + * @standard_input: (out) (allow-none): return location for file descriptor to write to child's stdin, or %NULL + * @standard_output: (out) (allow-none): return location for file descriptor to read child's stdout, or %NULL + * @standard_error: (out) (allow-none): return location for file descriptor to read child's stderr, or %NULL + * @error: return location for error + * + * Executes a child program asynchronously (your program will not + * block waiting for the child to exit). The child program is + * specified by the only argument that must be provided, @argv. @argv + * should be a %NULL-terminated array of strings, to be passed as the + * argument vector for the child. The first string in @argv is of + * course the name of the program to execute. By default, the name of + * the program must be a full path; the <envar>PATH</envar> shell variable + * will only be searched if you pass the %G_SPAWN_SEARCH_PATH flag. + * If the program name is not a full path and %G_SPAWN_SEARCH_PATH flag is not + * used, then the program will be run from the current directory (or + * @working_directory, if specified); this might be unexpected or even + * dangerous in some cases when the current directory is world-writable. + * + * On Windows, note that all the string or string vector arguments to + * this function and the other g_spawn*() functions are in UTF-8, the + * GLib file name encoding. Unicode characters that are not part of + * the system codepage passed in these arguments will be correctly + * available in the spawned program only if it uses wide character API + * to retrieve its command line. For C programs built with Microsoft's + * tools it is enough to make the program have a wmain() instead of + * main(). wmain() has a wide character argument vector as parameter. + * + * At least currently, mingw doesn't support wmain(), so if you use + * mingw to develop the spawned program, it will have to call the + * undocumented function __wgetmainargs() to get the wide character + * argument vector and environment. See gspawn-win32-helper.c in the + * GLib sources or init.c in the mingw runtime sources for a prototype + * for that function. Alternatively, you can retrieve the Win32 system + * level wide character command line passed to the spawned program + * using the GetCommandLineW() function. + * + * On Windows the low-level child process creation API + * <function>CreateProcess()</function> doesn't use argument vectors, + * but a command line. The C runtime library's + * <function>spawn*()</function> family of functions (which + * g_spawn_async_with_pipes() eventually calls) paste the argument + * vector elements together into a command line, and the C runtime startup code + * does a corresponding reconstruction of an argument vector from the + * command line, to be passed to main(). Complications arise when you have + * argument vector elements that contain spaces of double quotes. The + * <function>spawn*()</function> functions don't do any quoting or + * escaping, but on the other hand the startup code does do unquoting + * and unescaping in order to enable receiving arguments with embedded + * spaces or double quotes. To work around this asymmetry, + * g_spawn_async_with_pipes() will do quoting and escaping on argument + * vector elements that need it before calling the C runtime + * spawn() function. + * + * The returned @child_pid on Windows is a handle to the child + * process, not its identifier. Process handles and process + * identifiers are different concepts on Windows. + * + * @envp is a %NULL-terminated array of strings, where each string + * has the form <literal>KEY=VALUE</literal>. This will become + * the child's environment. If @envp is %NULL, the child inherits its + * parent's environment. + * + * @flags should be the bitwise OR of any flags you want to affect the + * function's behaviour. The %G_SPAWN_DO_NOT_REAP_CHILD means that the + * child will not automatically be reaped; you must use a child watch to + * be notified about the death of the child process. Eventually you must + * call g_spawn_close_pid() on the @child_pid, in order to free + * resources which may be associated with the child process. (On Unix, + * using a child watch is equivalent to calling waitpid() or handling + * the <literal>SIGCHLD</literal> signal manually. On Windows, calling g_spawn_close_pid() + * is equivalent to calling CloseHandle() on the process handle returned + * in @child_pid). See g_child_watch_add(). + * + * %G_SPAWN_LEAVE_DESCRIPTORS_OPEN means that the parent's open file + * descriptors will be inherited by the child; otherwise all + * descriptors except stdin/stdout/stderr will be closed before + * calling exec() in the child. %G_SPAWN_SEARCH_PATH + * means that <literal>argv[0]</literal> need not be an absolute path, it + * will be looked for in the user's <envar>PATH</envar>. + * %G_SPAWN_STDOUT_TO_DEV_NULL means that the child's standard output will + * be discarded, instead of going to the same location as the parent's + * standard output. If you use this flag, @standard_output must be %NULL. + * %G_SPAWN_STDERR_TO_DEV_NULL means that the child's standard error + * will be discarded, instead of going to the same location as the parent's + * standard error. If you use this flag, @standard_error must be %NULL. + * %G_SPAWN_CHILD_INHERITS_STDIN means that the child will inherit the parent's + * standard input (by default, the child's standard input is attached to + * /dev/null). If you use this flag, @standard_input must be %NULL. + * %G_SPAWN_FILE_AND_ARGV_ZERO means that the first element of @argv is + * the file to execute, while the remaining elements are the + * actual argument vector to pass to the file. Normally + * g_spawn_async_with_pipes() uses @argv[0] as the file to execute, and + * passes all of @argv to the child. + * + * @child_setup and @user_data are a function and user data. On POSIX + * platforms, the function is called in the child after GLib has + * performed all the setup it plans to perform (including creating + * pipes, closing file descriptors, etc.) but before calling + * exec(). That is, @child_setup is called just + * before calling exec() in the child. Obviously + * actions taken in this function will only affect the child, not the + * parent. + * + * On Windows, there is no separate fork() and exec() + * functionality. Child processes are created and run with a single + * API call, CreateProcess(). There is no sensible thing @child_setup + * could be used for on Windows so it is ignored and not called. + * + * If non-%NULL, @child_pid will on Unix be filled with the child's + * process ID. You can use the process ID to send signals to the + * child, or to use g_child_watch_add() (or waitpid()) if you specified the + * %G_SPAWN_DO_NOT_REAP_CHILD flag. On Windows, @child_pid will be + * filled with a handle to the child process only if you specified the + * %G_SPAWN_DO_NOT_REAP_CHILD flag. You can then access the child + * process using the Win32 API, for example wait for its termination + * with the <function>WaitFor*()</function> functions, or examine its + * exit code with GetExitCodeProcess(). You should close the handle + * with CloseHandle() or g_spawn_close_pid() when you no longer need it. + * + * If non-%NULL, the @standard_input, @standard_output, @standard_error + * locations will be filled with file descriptors for writing to the child's + * standard input or reading from its standard output or standard error. + * The caller of g_spawn_async_with_pipes() must close these file descriptors + * when they are no longer in use. If these parameters are %NULL, the corresponding + * pipe won't be created. + * + * If @standard_input is NULL, the child's standard input is attached to + * /dev/null unless %G_SPAWN_CHILD_INHERITS_STDIN is set. + * + * If @standard_error is NULL, the child's standard error goes to the same + * location as the parent's standard error unless %G_SPAWN_STDERR_TO_DEV_NULL + * is set. + * + * If @standard_output is NULL, the child's standard output goes to the same + * location as the parent's standard output unless %G_SPAWN_STDOUT_TO_DEV_NULL + * is set. + * + * @error can be %NULL to ignore errors, or non-%NULL to report errors. + * If an error is set, the function returns %FALSE. Errors + * are reported even if they occur in the child (for example if the + * executable in <literal>argv[0]</literal> is not found). Typically + * the <literal>message</literal> field of returned errors should be displayed + * to users. Possible errors are those from the #G_SPAWN_ERROR domain. + * + * If an error occurs, @child_pid, @standard_input, @standard_output, + * and @standard_error will not be filled with valid values. + * + * If @child_pid is not %NULL and an error does not occur then the returned + * process reference must be closed using g_spawn_close_pid(). + * + * <note><para> + * If you are writing a GTK+ application, and the program you + * are spawning is a graphical application, too, then you may + * want to use gdk_spawn_on_screen_with_pipes() instead to ensure that + * the spawned program opens its windows on the right screen. + * </para></note> + * + * Return value: %TRUE on success, %FALSE if an error was set + **/ +gboolean +g_spawn_async_with_pipes (const gchar *working_directory, + gchar **argv, + gchar **envp, + GSpawnFlags flags, + GSpawnChildSetupFunc child_setup, + gpointer user_data, + GPid *child_pid, + gint *standard_input, + gint *standard_output, + gint *standard_error, + GError **error) +{ + g_return_val_if_fail (argv != NULL, FALSE); + g_return_val_if_fail (standard_output == NULL || + !(flags & G_SPAWN_STDOUT_TO_DEV_NULL), FALSE); + g_return_val_if_fail (standard_error == NULL || + !(flags & G_SPAWN_STDERR_TO_DEV_NULL), FALSE); + /* can't inherit stdin if we have an input pipe. */ + g_return_val_if_fail (standard_input == NULL || + !(flags & G_SPAWN_CHILD_INHERITS_STDIN), FALSE); + + return fork_exec_with_pipes (!(flags & G_SPAWN_DO_NOT_REAP_CHILD), + working_directory, + argv, + envp, + !(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN), + (flags & G_SPAWN_SEARCH_PATH) != 0, + (flags & G_SPAWN_STDOUT_TO_DEV_NULL) != 0, + (flags & G_SPAWN_STDERR_TO_DEV_NULL) != 0, + (flags & G_SPAWN_CHILD_INHERITS_STDIN) != 0, + (flags & G_SPAWN_FILE_AND_ARGV_ZERO) != 0, + child_setup, + user_data, + child_pid, + standard_input, + standard_output, + standard_error, + error); +} + +/** + * g_spawn_command_line_sync: + * @command_line: a command line + * @standard_output: (out) (array zero-terminated=1) (element-type guint8) (allow-none): return location for child output + * @standard_error: (out) (array zero-terminated=1) (element-type guint8) (allow-none): return location for child errors + * @exit_status: (out) (allow-none): return location for child exit status, as returned by waitpid() + * @error: return location for errors + * + * A simple version of g_spawn_sync() with little-used parameters + * removed, taking a command line instead of an argument vector. See + * g_spawn_sync() for full details. @command_line will be parsed by + * g_shell_parse_argv(). Unlike g_spawn_sync(), the %G_SPAWN_SEARCH_PATH flag + * is enabled. Note that %G_SPAWN_SEARCH_PATH can have security + * implications, so consider using g_spawn_sync() directly if + * appropriate. Possible errors are those from g_spawn_sync() and those + * from g_shell_parse_argv(). + * + * If @exit_status is non-%NULL, the exit status of the child is stored there as + * it would be returned by waitpid(); standard UNIX macros such as WIFEXITED() + * and WEXITSTATUS() must be used to evaluate the exit status. + * + * On Windows, please note the implications of g_shell_parse_argv() + * parsing @command_line. Parsing is done according to Unix shell rules, not + * Windows command interpreter rules. + * Space is a separator, and backslashes are + * special. Thus you cannot simply pass a @command_line containing + * canonical Windows paths, like "c:\\program files\\app\\app.exe", as + * the backslashes will be eaten, and the space will act as a + * separator. You need to enclose such paths with single quotes, like + * "'c:\\program files\\app\\app.exe' 'e:\\folder\\argument.txt'". + * + * Return value: %TRUE on success, %FALSE if an error was set + **/ +gboolean +g_spawn_command_line_sync (const gchar *command_line, + gchar **standard_output, + gchar **standard_error, + gint *exit_status, + GError **error) +{ + gboolean retval; + gchar **argv = NULL; + + g_return_val_if_fail (command_line != NULL, FALSE); + + if (!g_shell_parse_argv (command_line, + NULL, &argv, + error)) + return FALSE; + + retval = g_spawn_sync (NULL, + argv, + NULL, + G_SPAWN_SEARCH_PATH, + NULL, + NULL, + standard_output, + standard_error, + exit_status, + error); + g_strfreev (argv); + + return retval; +} + +/** + * g_spawn_command_line_async: + * @command_line: a command line + * @error: return location for errors + * + * A simple version of g_spawn_async() that parses a command line with + * g_shell_parse_argv() and passes it to g_spawn_async(). Runs a + * command line in the background. Unlike g_spawn_async(), the + * %G_SPAWN_SEARCH_PATH flag is enabled, other flags are not. Note + * that %G_SPAWN_SEARCH_PATH can have security implications, so + * consider using g_spawn_async() directly if appropriate. Possible + * errors are those from g_shell_parse_argv() and g_spawn_async(). + * + * The same concerns on Windows apply as for g_spawn_command_line_sync(). + * + * Return value: %TRUE on success, %FALSE if error is set. + **/ +gboolean +g_spawn_command_line_async (const gchar *command_line, + GError **error) +{ + gboolean retval; + gchar **argv = NULL; + + g_return_val_if_fail (command_line != NULL, FALSE); + + if (!g_shell_parse_argv (command_line, + NULL, &argv, + error)) + return FALSE; + + retval = g_spawn_async (NULL, + argv, + NULL, + G_SPAWN_SEARCH_PATH, + NULL, + NULL, + NULL, + error); + g_strfreev (argv); + + return retval; +} + +static gint +exec_err_to_g_error (gint en) +{ + switch (en) + { +#ifdef EACCES + case EACCES: + return G_SPAWN_ERROR_ACCES; + break; +#endif + +#ifdef EPERM + case EPERM: + return G_SPAWN_ERROR_PERM; + break; +#endif + +#ifdef E2BIG + case E2BIG: + return G_SPAWN_ERROR_TOO_BIG; + break; +#endif + +#ifdef ENOEXEC + case ENOEXEC: + return G_SPAWN_ERROR_NOEXEC; + break; +#endif + +#ifdef ENAMETOOLONG + case ENAMETOOLONG: + return G_SPAWN_ERROR_NAMETOOLONG; + break; +#endif + +#ifdef ENOENT + case ENOENT: + return G_SPAWN_ERROR_NOENT; + break; +#endif + +#ifdef ENOMEM + case ENOMEM: + return G_SPAWN_ERROR_NOMEM; + break; +#endif + +#ifdef ENOTDIR + case ENOTDIR: + return G_SPAWN_ERROR_NOTDIR; + break; +#endif + +#ifdef ELOOP + case ELOOP: + return G_SPAWN_ERROR_LOOP; + break; +#endif + +#ifdef ETXTBUSY + case ETXTBUSY: + return G_SPAWN_ERROR_TXTBUSY; + break; +#endif + +#ifdef EIO + case EIO: + return G_SPAWN_ERROR_IO; + break; +#endif + +#ifdef ENFILE + case ENFILE: + return G_SPAWN_ERROR_NFILE; + break; +#endif + +#ifdef EMFILE + case EMFILE: + return G_SPAWN_ERROR_MFILE; + break; +#endif + +#ifdef EINVAL + case EINVAL: + return G_SPAWN_ERROR_INVAL; + break; +#endif + +#ifdef EISDIR + case EISDIR: + return G_SPAWN_ERROR_ISDIR; + break; +#endif + +#ifdef ELIBBAD + case ELIBBAD: + return G_SPAWN_ERROR_LIBBAD; + break; +#endif + + default: + return G_SPAWN_ERROR_FAILED; + break; + } +} + +static gssize +write_all (gint fd, gconstpointer vbuf, gsize to_write) +{ + gchar *buf = (gchar *) vbuf; + + while (to_write > 0) + { + gssize count = write (fd, buf, to_write); + if (count < 0) + { + if (errno != EINTR) + return FALSE; + } + else + { + to_write -= count; + buf += count; + } + } + + return TRUE; +} + +G_GNUC_NORETURN +static void +write_err_and_exit (gint fd, gint msg) +{ + gint en = errno; + + write_all (fd, &msg, sizeof(msg)); + write_all (fd, &en, sizeof(en)); + + _exit (1); +} + +static int +set_cloexec (void *data, gint fd) +{ + if (fd >= GPOINTER_TO_INT (data)) + fcntl (fd, F_SETFD, FD_CLOEXEC); + + return 0; +} + +#ifndef HAVE_FDWALK +static int +fdwalk (int (*cb)(void *data, int fd), void *data) +{ + gint open_max; + gint fd; + gint res = 0; + +#ifdef HAVE_SYS_RESOURCE_H + struct rlimit rl; +#endif + +#ifdef __linux__ + DIR *d; + + if ((d = opendir("/proc/self/fd"))) { + struct dirent *de; + + while ((de = readdir(d))) { + glong l; + gchar *e = NULL; + + if (de->d_name[0] == '.') + continue; + + errno = 0; + l = strtol(de->d_name, &e, 10); + if (errno != 0 || !e || *e) + continue; + + fd = (gint) l; + + if ((glong) fd != l) + continue; + + if (fd == dirfd(d)) + continue; + + if ((res = cb (data, fd)) != 0) + break; + } + + closedir(d); + return res; + } + + /* If /proc is not mounted or not accessible we fall back to the old + * rlimit trick */ + +#endif + +#ifdef HAVE_SYS_RESOURCE_H + + if (getrlimit(RLIMIT_NOFILE, &rl) == 0 && rl.rlim_max != RLIM_INFINITY) + open_max = rl.rlim_max; + else +#endif + open_max = sysconf (_SC_OPEN_MAX); + + for (fd = 0; fd < open_max; fd++) + if ((res = cb (data, fd)) != 0) + break; + + return res; +} +#endif + +static gint +sane_dup2 (gint fd1, gint fd2) +{ + gint ret; + + retry: + ret = dup2 (fd1, fd2); + if (ret < 0 && errno == EINTR) + goto retry; + + return ret; +} + +static gint +sane_open (const char *path, gint mode) +{ + gint ret; + + retry: + ret = open (path, mode); + if (ret < 0 && errno == EINTR) + goto retry; + + return ret; +} + +enum +{ + CHILD_CHDIR_FAILED, + CHILD_EXEC_FAILED, + CHILD_DUP2_FAILED, + CHILD_FORK_FAILED +}; + +static void +do_exec (gint child_err_report_fd, + gint stdin_fd, + gint stdout_fd, + gint stderr_fd, + const gchar *working_directory, + gchar **argv, + gchar **envp, + gboolean close_descriptors, + gboolean search_path, + gboolean stdout_to_null, + gboolean stderr_to_null, + gboolean child_inherits_stdin, + gboolean file_and_argv_zero, + GSpawnChildSetupFunc child_setup, + gpointer user_data) +{ + if (working_directory && chdir (working_directory) < 0) + write_err_and_exit (child_err_report_fd, + CHILD_CHDIR_FAILED); + + /* Close all file descriptors but stdin stdout and stderr as + * soon as we exec. Note that this includes + * child_err_report_fd, which keeps the parent from blocking + * forever on the other end of that pipe. + */ + if (close_descriptors) + { + fdwalk (set_cloexec, GINT_TO_POINTER(3)); + } + else + { + /* We need to do child_err_report_fd anyway */ + set_cloexec (GINT_TO_POINTER(0), child_err_report_fd); + } + + /* Redirect pipes as required */ + + if (stdin_fd >= 0) + { + /* dup2 can't actually fail here I don't think */ + + if (sane_dup2 (stdin_fd, 0) < 0) + write_err_and_exit (child_err_report_fd, + CHILD_DUP2_FAILED); + + /* ignore this if it doesn't work */ + close_and_invalidate (&stdin_fd); + } + else if (!child_inherits_stdin) + { + /* Keep process from blocking on a read of stdin */ + gint read_null = open ("/dev/null", O_RDONLY); + g_assert (read_null != -1); + sane_dup2 (read_null, 0); + close_and_invalidate (&read_null); + } + + if (stdout_fd >= 0) + { + /* dup2 can't actually fail here I don't think */ + + if (sane_dup2 (stdout_fd, 1) < 0) + write_err_and_exit (child_err_report_fd, + CHILD_DUP2_FAILED); + + /* ignore this if it doesn't work */ + close_and_invalidate (&stdout_fd); + } + else if (stdout_to_null) + { + gint write_null = sane_open ("/dev/null", O_WRONLY); + g_assert (write_null != -1); + sane_dup2 (write_null, 1); + close_and_invalidate (&write_null); + } + + if (stderr_fd >= 0) + { + /* dup2 can't actually fail here I don't think */ + + if (sane_dup2 (stderr_fd, 2) < 0) + write_err_and_exit (child_err_report_fd, + CHILD_DUP2_FAILED); + + /* ignore this if it doesn't work */ + close_and_invalidate (&stderr_fd); + } + else if (stderr_to_null) + { + gint write_null = sane_open ("/dev/null", O_WRONLY); + sane_dup2 (write_null, 2); + close_and_invalidate (&write_null); + } + + /* Call user function just before we exec */ + if (child_setup) + { + (* child_setup) (user_data); + } + + g_execute (argv[0], + file_and_argv_zero ? argv + 1 : argv, + envp, search_path); + + /* Exec failed */ + write_err_and_exit (child_err_report_fd, + CHILD_EXEC_FAILED); +} + +static gboolean +read_ints (int fd, + gint* buf, + gint n_ints_in_buf, + gint *n_ints_read, + GError **error) +{ + gsize bytes = 0; + + while (TRUE) + { + gssize chunk; + + if (bytes >= sizeof(gint)*2) + break; /* give up, who knows what happened, should not be + * possible. + */ + + again: + chunk = read (fd, + ((gchar*)buf) + bytes, + sizeof(gint) * n_ints_in_buf - bytes); + if (chunk < 0 && errno == EINTR) + goto again; + + if (chunk < 0) + { + int errsv = errno; + + /* Some weird shit happened, bail out */ + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_FAILED, + _("Failed to read from child pipe (%s)"), + g_strerror (errsv)); + + return FALSE; + } + else if (chunk == 0) + break; /* EOF */ + else /* chunk > 0 */ + bytes += chunk; + } + + *n_ints_read = (gint)(bytes / sizeof(gint)); + + return TRUE; +} + +static gboolean +fork_exec_with_pipes (gboolean intermediate_child, + const gchar *working_directory, + gchar **argv, + gchar **envp, + gboolean close_descriptors, + gboolean search_path, + gboolean stdout_to_null, + gboolean stderr_to_null, + gboolean child_inherits_stdin, + gboolean file_and_argv_zero, + GSpawnChildSetupFunc child_setup, + gpointer user_data, + GPid *child_pid, + gint *standard_input, + gint *standard_output, + gint *standard_error, + GError **error) +{ + GPid pid = -1; + gint stdin_pipe[2] = { -1, -1 }; + gint stdout_pipe[2] = { -1, -1 }; + gint stderr_pipe[2] = { -1, -1 }; + gint child_err_report_pipe[2] = { -1, -1 }; + gint child_pid_report_pipe[2] = { -1, -1 }; + gint status; + + if (!make_pipe (child_err_report_pipe, error)) + return FALSE; + + if (intermediate_child && !make_pipe (child_pid_report_pipe, error)) + goto cleanup_and_fail; + + if (standard_input && !make_pipe (stdin_pipe, error)) + goto cleanup_and_fail; + + if (standard_output && !make_pipe (stdout_pipe, error)) + goto cleanup_and_fail; + + if (standard_error && !make_pipe (stderr_pipe, error)) + goto cleanup_and_fail; + + pid = fork (); + + if (pid < 0) + { + int errsv = errno; + + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_FORK, + _("Failed to fork (%s)"), + g_strerror (errsv)); + + goto cleanup_and_fail; + } + else if (pid == 0) + { + /* Immediate child. This may or may not be the child that + * actually execs the new process. + */ + + /* Reset some signal handlers that we may use */ + signal (SIGCHLD, SIG_DFL); + signal (SIGINT, SIG_DFL); + signal (SIGTERM, SIG_DFL); + signal (SIGHUP, SIG_DFL); + + /* Be sure we crash if the parent exits + * and we write to the err_report_pipe + */ + signal (SIGPIPE, SIG_DFL); + + /* Close the parent's end of the pipes; + * not needed in the close_descriptors case, + * though + */ + close_and_invalidate (&child_err_report_pipe[0]); + close_and_invalidate (&child_pid_report_pipe[0]); + close_and_invalidate (&stdin_pipe[1]); + close_and_invalidate (&stdout_pipe[0]); + close_and_invalidate (&stderr_pipe[0]); + + if (intermediate_child) + { + /* We need to fork an intermediate child that launches the + * final child. The purpose of the intermediate child + * is to exit, so we can waitpid() it immediately. + * Then the grandchild will not become a zombie. + */ + GPid grandchild_pid; + + grandchild_pid = fork (); + + if (grandchild_pid < 0) + { + /* report -1 as child PID */ + write_all (child_pid_report_pipe[1], &grandchild_pid, + sizeof(grandchild_pid)); + + write_err_and_exit (child_err_report_pipe[1], + CHILD_FORK_FAILED); + } + else if (grandchild_pid == 0) + { + do_exec (child_err_report_pipe[1], + stdin_pipe[0], + stdout_pipe[1], + stderr_pipe[1], + working_directory, + argv, + envp, + close_descriptors, + search_path, + stdout_to_null, + stderr_to_null, + child_inherits_stdin, + file_and_argv_zero, + child_setup, + user_data); + } + else + { + write_all (child_pid_report_pipe[1], &grandchild_pid, sizeof(grandchild_pid)); + close_and_invalidate (&child_pid_report_pipe[1]); + + _exit (0); + } + } + else + { + /* Just run the child. + */ + + do_exec (child_err_report_pipe[1], + stdin_pipe[0], + stdout_pipe[1], + stderr_pipe[1], + working_directory, + argv, + envp, + close_descriptors, + search_path, + stdout_to_null, + stderr_to_null, + child_inherits_stdin, + file_and_argv_zero, + child_setup, + user_data); + } + } + else + { + /* Parent */ + + gint buf[2]; + gint n_ints = 0; + + /* Close the uncared-about ends of the pipes */ + close_and_invalidate (&child_err_report_pipe[1]); + close_and_invalidate (&child_pid_report_pipe[1]); + close_and_invalidate (&stdin_pipe[0]); + close_and_invalidate (&stdout_pipe[1]); + close_and_invalidate (&stderr_pipe[1]); + + /* If we had an intermediate child, reap it */ + if (intermediate_child) + { + wait_again: + if (waitpid (pid, &status, 0) < 0) + { + if (errno == EINTR) + goto wait_again; + else if (errno == ECHILD) + ; /* do nothing, child already reaped */ + else + g_warning ("waitpid() should not fail in " + "'fork_exec_with_pipes'"); + } + } + + + if (!read_ints (child_err_report_pipe[0], + buf, 2, &n_ints, + error)) + goto cleanup_and_fail; + + if (n_ints >= 2) + { + /* Error from the child. */ + + switch (buf[0]) + { + case CHILD_CHDIR_FAILED: + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_CHDIR, + _("Failed to change to directory '%s' (%s)"), + working_directory, + g_strerror (buf[1])); + + break; + + case CHILD_EXEC_FAILED: + g_set_error (error, + G_SPAWN_ERROR, + exec_err_to_g_error (buf[1]), + _("Failed to execute child process \"%s\" (%s)"), + argv[0], + g_strerror (buf[1])); + + break; + + case CHILD_DUP2_FAILED: + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_FAILED, + _("Failed to redirect output or input of child process (%s)"), + g_strerror (buf[1])); + + break; + + case CHILD_FORK_FAILED: + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_FORK, + _("Failed to fork child process (%s)"), + g_strerror (buf[1])); + break; + + default: + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_FAILED, + _("Unknown error executing child process \"%s\""), + argv[0]); + break; + } + + goto cleanup_and_fail; + } + + /* Get child pid from intermediate child pipe. */ + if (intermediate_child) + { + n_ints = 0; + + if (!read_ints (child_pid_report_pipe[0], + buf, 1, &n_ints, error)) + goto cleanup_and_fail; + + if (n_ints < 1) + { + int errsv = errno; + + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_FAILED, + _("Failed to read enough data from child pid pipe (%s)"), + g_strerror (errsv)); + goto cleanup_and_fail; + } + else + { + /* we have the child pid */ + pid = buf[0]; + } + } + + /* Success against all odds! return the information */ + close_and_invalidate (&child_err_report_pipe[0]); + close_and_invalidate (&child_pid_report_pipe[0]); + + if (child_pid) + *child_pid = pid; + + if (standard_input) + *standard_input = stdin_pipe[1]; + if (standard_output) + *standard_output = stdout_pipe[0]; + if (standard_error) + *standard_error = stderr_pipe[0]; + + return TRUE; + } + + cleanup_and_fail: + + /* There was an error from the Child, reap the child to avoid it being + a zombie. + */ + + if (pid > 0) + { + wait_failed: + if (waitpid (pid, NULL, 0) < 0) + { + if (errno == EINTR) + goto wait_failed; + else if (errno == ECHILD) + ; /* do nothing, child already reaped */ + else + g_warning ("waitpid() should not fail in " + "'fork_exec_with_pipes'"); + } + } + + close_and_invalidate (&child_err_report_pipe[0]); + close_and_invalidate (&child_err_report_pipe[1]); + close_and_invalidate (&child_pid_report_pipe[0]); + close_and_invalidate (&child_pid_report_pipe[1]); + close_and_invalidate (&stdin_pipe[0]); + close_and_invalidate (&stdin_pipe[1]); + close_and_invalidate (&stdout_pipe[0]); + close_and_invalidate (&stdout_pipe[1]); + close_and_invalidate (&stderr_pipe[0]); + close_and_invalidate (&stderr_pipe[1]); + + return FALSE; +} + +static gboolean +make_pipe (gint p[2], + GError **error) +{ + if (pipe (p) < 0) + { + gint errsv = errno; + g_set_error (error, + G_SPAWN_ERROR, + G_SPAWN_ERROR_FAILED, + _("Failed to create pipe for communicating with child process (%s)"), + g_strerror (errsv)); + return FALSE; + } + else + return TRUE; +} + +/* Based on execvp from GNU C Library */ + +static void +script_execute (const gchar *file, + gchar **argv, + gchar **envp, + gboolean search_path) +{ + /* Count the arguments. */ + int argc = 0; + while (argv[argc]) + ++argc; + + /* Construct an argument list for the shell. */ + { + gchar **new_argv; + + new_argv = g_new0 (gchar*, argc + 2); /* /bin/sh and NULL */ + + new_argv[0] = (char *) "/bin/sh"; + new_argv[1] = (char *) file; + while (argc > 0) + { + new_argv[argc + 1] = argv[argc]; + --argc; + } + + /* Execute the shell. */ + if (envp) + execve (new_argv[0], new_argv, envp); + else + execv (new_argv[0], new_argv); + + g_free (new_argv); + } +} + +static gchar* +my_strchrnul (const gchar *str, gchar c) +{ + gchar *p = (gchar*) str; + while (*p && (*p != c)) + ++p; + + return p; +} + +static gint +g_execute (const gchar *file, + gchar **argv, + gchar **envp, + gboolean search_path) +{ + if (*file == '\0') + { + /* We check the simple case first. */ + errno = ENOENT; + return -1; + } + + if (!search_path || strchr (file, '/') != NULL) + { + /* Don't search when it contains a slash. */ + if (envp) + execve (file, argv, envp); + else + execv (file, argv); + + if (errno == ENOEXEC) + script_execute (file, argv, envp, FALSE); + } + else + { + gboolean got_eacces = 0; + const gchar *path, *p; + gchar *name, *freeme; + gsize len; + gsize pathlen; + + path = g_getenv ("PATH"); + if (path == NULL) + { + /* There is no `PATH' in the environment. The default + * search path in libc is the current directory followed by + * the path `confstr' returns for `_CS_PATH'. + */ + + /* In GLib we put . last, for security, and don't use the + * unportable confstr(); UNIX98 does not actually specify + * what to search if PATH is unset. POSIX may, dunno. + */ + + path = "/bin:/usr/bin:."; + } + + len = strlen (file) + 1; + pathlen = strlen (path); + freeme = name = g_malloc (pathlen + len + 1); + + /* Copy the file name at the top, including '\0' */ + memcpy (name + pathlen + 1, file, len); + name = name + pathlen; + /* And add the slash before the filename */ + *name = '/'; + + p = path; + do + { + char *startp; + + path = p; + p = my_strchrnul (path, ':'); + + if (p == path) + /* Two adjacent colons, or a colon at the beginning or the end + * of `PATH' means to search the current directory. + */ + startp = name + 1; + else + startp = memcpy (name - (p - path), path, p - path); + + /* Try to execute this name. If it works, execv will not return. */ + if (envp) + execve (startp, argv, envp); + else + execv (startp, argv); + + if (errno == ENOEXEC) + script_execute (startp, argv, envp, search_path); + + switch (errno) + { + case EACCES: + /* Record the we got a `Permission denied' error. If we end + * up finding no executable we can use, we want to diagnose + * that we did find one but were denied access. + */ + got_eacces = TRUE; + + /* FALL THRU */ + + case ENOENT: +#ifdef ESTALE + case ESTALE: +#endif +#ifdef ENOTDIR + case ENOTDIR: +#endif + /* Those errors indicate the file is missing or not executable + * by us, in which case we want to just try the next path + * directory. + */ + break; + + case ENODEV: + case ETIMEDOUT: + /* Some strange filesystems like AFS return even + * stranger error numbers. They cannot reasonably mean anything + * else so ignore those, too. + */ + break; + + default: + /* Some other error means we found an executable file, but + * something went wrong executing it; return the error to our + * caller. + */ + g_free (freeme); + return -1; + } + } + while (*p++ != '\0'); + + /* We tried every element and none of them worked. */ + if (got_eacces) + /* At least one failure was due to permissions, so report that + * error. + */ + errno = EACCES; + + g_free (freeme); + } + + /* Return the error from the last attempt (probably ENOENT). */ + return -1; +} + +/** + * g_spawn_close_pid: + * @pid: The process reference to close + * + * On some platforms, notably Windows, the #GPid type represents a resource + * which must be closed to prevent resource leaking. g_spawn_close_pid() + * is provided for this purpose. It should be used on all platforms, even + * though it doesn't do anything under UNIX. + **/ +void +g_spawn_close_pid (GPid pid) +{ +} |