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gspawn: Combine fork_exec() implementations

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This is an internal change which won’t affect the public API. It should
introduce no functional changes, but simplifies the code a little.

The arguments from `fork_exec_with_pipes()` have been added to
`fork_exec_with_fds()`. `child_close_fds` has been dropped since it’s
now an implementation detail within the function.

Signed-off-by: Philip Withnall <pwithnall@endlessos.org>

Helps: #2097
This commit is contained in:
Philip Withnall 2020-10-13 12:43:25 +01:00
parent 63467c559e
commit cddcd24b52
1 changed files with 194 additions and 236 deletions
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430
glib/gspawn.c
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@ -167,46 +167,28 @@ static gint g_execute (const gchar *file,
gchar *search_path_buffer,
gsize search_path_buffer_len);
static gboolean fork_exec_with_pipes (gboolean intermediate_child,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
gboolean cloexec_pipes,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *standard_input,
gint *standard_output,
gint *standard_error,
GError **error);
static gboolean fork_exec_with_fds (gboolean intermediate_child,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
gboolean cloexec_pipes,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *child_close_fds,
gint stdin_fd,
gint stdout_fd,
gint stderr_fd,
GError **error);
static gboolean fork_exec (gboolean intermediate_child,
const gchar *working_directory,
const gchar * const *argv,
const gchar * const *envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
gboolean cloexec_pipes,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *stdin_pipe_out,
gint *stdout_pipe_out,
gint *stderr_pipe_out,
gint stdin_fd,
gint stdout_fd,
gint stderr_fd,
GError **error);
G_DEFINE_QUARK (g-exec-error-quark, g_spawn_error)
G_DEFINE_QUARK (g-spawn-exit-error-quark, g_spawn_exit_error)
@ -264,6 +246,16 @@ g_spawn_async (const gchar *working_directory,
error);
}
/* This function is called between fork() and exec() and hence must be
* async-signal-safe (see signal-safety(7)). */
static gint
steal_fd (gint *fd)
{
gint fd_out = *fd;
*fd = -1;
return fd_out;
}
/* Avoids a danger in threaded situations (calling close()
* on a file descriptor twice, and another thread has
* re-opened it since the first close)
@ -402,25 +394,26 @@ g_spawn_sync (const gchar *working_directory,
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_SEARCH_PATH_FROM_ENVP) != 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,
(flags & G_SPAWN_CLOEXEC_PIPES) != 0,
child_setup,
user_data,
&pid,
NULL,
standard_output ? &outpipe : NULL,
standard_error ? &errpipe : NULL,
error))
if (!fork_exec (FALSE,
working_directory,
(const gchar * const *) argv,
(const gchar * const *) envp,
!(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
(flags & G_SPAWN_SEARCH_PATH) != 0,
(flags & G_SPAWN_SEARCH_PATH_FROM_ENVP) != 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,
(flags & G_SPAWN_CLOEXEC_PIPES) != 0,
child_setup,
user_data,
&pid,
NULL,
standard_output ? &outpipe : NULL,
standard_error ? &errpipe : NULL,
-1, -1, -1,
error))
return FALSE;
/* Read data from child. */
@ -789,25 +782,26 @@ g_spawn_async_with_pipes (const gchar *working_directory,
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_SEARCH_PATH_FROM_ENVP) != 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,
(flags & G_SPAWN_CLOEXEC_PIPES) != 0,
child_setup,
user_data,
child_pid,
standard_input,
standard_output,
standard_error,
error);
return fork_exec (!(flags & G_SPAWN_DO_NOT_REAP_CHILD),
working_directory,
(const gchar * const *) argv,
(const gchar * const *) envp,
!(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
(flags & G_SPAWN_SEARCH_PATH) != 0,
(flags & G_SPAWN_SEARCH_PATH_FROM_ENVP) != 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,
(flags & G_SPAWN_CLOEXEC_PIPES) != 0,
child_setup,
user_data,
child_pid,
standard_input,
standard_output,
standard_error,
-1, -1, -1,
error);
}
/**
@ -869,26 +863,26 @@ g_spawn_async_with_fds (const gchar *working_directory,
g_return_val_if_fail (stdin_fd < 0 ||
!(flags & G_SPAWN_CHILD_INHERITS_STDIN), FALSE);
return fork_exec_with_fds (!(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_SEARCH_PATH_FROM_ENVP) != 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,
(flags & G_SPAWN_CLOEXEC_PIPES) != 0,
child_setup,
user_data,
child_pid,
NULL,
stdin_fd,
stdout_fd,
stderr_fd,
error);
return fork_exec (!(flags & G_SPAWN_DO_NOT_REAP_CHILD),
working_directory,
(const gchar * const *) argv,
(const gchar * const *) envp,
!(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
(flags & G_SPAWN_SEARCH_PATH) != 0,
(flags & G_SPAWN_SEARCH_PATH_FROM_ENVP) != 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,
(flags & G_SPAWN_CLOEXEC_PIPES) != 0,
child_setup,
user_data,
child_pid,
NULL, NULL, NULL,
stdin_fd,
stdout_fd,
stderr_fd,
error);
}
/**
@ -1389,10 +1383,10 @@ do_exec (gint child_err_report_fd,
gint stdout_fd,
gint stderr_fd,
const gchar *working_directory,
gchar **argv,
const gchar * const *argv,
gchar **argv_buffer,
gsize argv_buffer_len,
gchar **envp,
const gchar * const *envp,
gboolean close_descriptors,
const gchar *search_path,
gchar *search_path_buffer,
@ -1499,9 +1493,9 @@ do_exec (gint child_err_report_fd,
}
g_execute (argv[0],
file_and_argv_zero ? argv + 1 : argv,
(gchar **) (file_and_argv_zero ? argv + 1 : argv),
argv_buffer, argv_buffer_len,
envp, search_path, search_path_buffer, search_path_buffer_len);
(gchar **) envp, search_path, search_path_buffer, search_path_buffer_len);
/* Exec failed */
write_err_and_exit (child_err_report_fd,
@ -1559,8 +1553,8 @@ read_ints (int fd,
#ifdef POSIX_SPAWN_AVAILABLE
static gboolean
do_posix_spawn (gchar **argv,
gchar **envp,
do_posix_spawn (const gchar * const *argv,
const gchar * const *envp,
gboolean search_path,
gboolean stdout_to_null,
gboolean stderr_to_null,
@ -1573,7 +1567,7 @@ do_posix_spawn (gchar **argv,
gint stderr_fd)
{
pid_t pid;
gchar **argv_pass;
const gchar * const *argv_pass;
posix_spawnattr_t attr;
posix_spawn_file_actions_t file_actions;
gint parent_close_fds[3];
@ -1712,13 +1706,13 @@ do_posix_spawn (gchar **argv,
argv_pass = file_and_argv_zero ? argv + 1 : argv;
if (envp == NULL)
envp = environ;
envp = (const gchar * const *) environ;
/* Don't search when it contains a slash. */
if (!search_path || strchr (argv[0], '/') != NULL)
r = posix_spawn (&pid, argv[0], &file_actions, &attr, argv_pass, envp);
r = posix_spawn (&pid, argv[0], &file_actions, &attr, (char * const *) argv_pass, (char * const *) envp);
else
r = posix_spawnp (&pid, argv[0], &file_actions, &attr, argv_pass, envp);
r = posix_spawnp (&pid, argv[0], &file_actions, &attr, (char * const *) argv_pass, (char * const *) envp);
if (r == 0 && child_pid != NULL)
*child_pid = pid;
@ -1737,26 +1731,28 @@ out_free_spawnattr:
#endif /* POSIX_SPAWN_AVAILABLE */
static gboolean
fork_exec_with_fds (gboolean intermediate_child,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
gboolean cloexec_pipes,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *child_close_fds,
gint stdin_fd,
gint stdout_fd,
gint stderr_fd,
GError **error)
fork_exec (gboolean intermediate_child,
const gchar *working_directory,
const gchar * const *argv,
const gchar * const *envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
gboolean cloexec_pipes,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *stdin_pipe_out,
gint *stdout_pipe_out,
gint *stderr_pipe_out,
gint stdin_fd,
gint stdout_fd,
gint stderr_fd,
GError **error)
{
GPid pid = -1;
gint child_err_report_pipe[2] = { -1, -1 };
@ -1770,6 +1766,42 @@ fork_exec_with_fds (gboolean intermediate_child,
gchar **argv_buffer = NULL;
gchar **argv_buffer_heap = NULL;
gsize argv_buffer_len = 0;
gint stdin_pipe[2] = { -1, -1 };
gint stdout_pipe[2] = { -1, -1 };
gint stderr_pipe[2] = { -1, -1 };
gint child_close_fds[4] = { -1, -1, -1, -1 };
gint n_child_close_fds = 0;
g_assert (stdin_pipe_out == NULL || stdin_fd < 0);
g_assert (stdout_pipe_out == NULL || stdout_fd < 0);
g_assert (stderr_pipe_out == NULL || stderr_fd < 0);
/* If pipes have been requested, open them */
if (stdin_pipe_out != NULL)
{
if (!g_unix_open_pipe (stdin_pipe, pipe_flags, error))
goto cleanup_and_fail;
child_close_fds[n_child_close_fds++] = stdin_pipe[1];
stdin_fd = stdin_pipe[0];
}
if (stdout_pipe_out != NULL)
{
if (!g_unix_open_pipe (stdout_pipe, pipe_flags, error))
goto cleanup_and_fail;
child_close_fds[n_child_close_fds++] = stdout_pipe[0];
stdout_fd = stdout_pipe[1];
}
if (stderr_pipe_out != NULL)
{
if (!g_unix_open_pipe (stderr_pipe, pipe_flags, error))
goto cleanup_and_fail;
child_close_fds[n_child_close_fds++] = stderr_pipe[0];
stderr_fd = stderr_pipe[1];
}
child_close_fds[n_child_close_fds++] = -1;
#ifdef POSIX_SPAWN_AVAILABLE
if (!intermediate_child && working_directory == NULL && !close_descriptors &&
@ -1792,7 +1824,7 @@ fork_exec_with_fds (gboolean intermediate_child,
stdout_fd,
stderr_fd);
if (status == 0)
return TRUE;
goto success;
if (status != ENOEXEC)
{
@ -1802,7 +1834,7 @@ fork_exec_with_fds (gboolean intermediate_child,
_("Failed to spawn child process “%s” (%s)"),
argv[0],
g_strerror (status));
return FALSE;
goto cleanup_and_fail;
}
/* posix_spawn is not intended to support script execution. It does in
@ -1829,7 +1861,7 @@ fork_exec_with_fds (gboolean intermediate_child,
* as getenv() isn’t async-signal-safe (see `man 7 signal-safety`). */
chosen_search_path = NULL;
if (search_path_from_envp)
chosen_search_path = g_environ_getenv (envp, "PATH");
chosen_search_path = g_environ_getenv ((gchar **) envp, "PATH");
if (search_path && chosen_search_path == NULL)
chosen_search_path = g_getenv ("PATH");
@ -1883,7 +1915,7 @@ fork_exec_with_fds (gboolean intermediate_child,
/* And allocate a buffer which is 2 elements longer than @argv, so that if
* script_execute() has to be called later on, it can build a wrapper argv
* array in this buffer. */
argv_buffer_len = g_strv_length (argv) + 2;
argv_buffer_len = g_strv_length ((gchar **) argv) + 2;
if (argv_buffer_len < 4000 / sizeof (gchar *))
{
/* Prefer small stack allocations to avoid valgrind leak warnings
@ -1897,11 +1929,7 @@ fork_exec_with_fds (gboolean intermediate_child,
}
if (!g_unix_open_pipe (child_err_report_pipe, pipe_flags, error))
{
g_free (search_path_buffer_heap);
g_free (argv_buffer_heap);
return FALSE;
}
goto cleanup_and_fail;
if (intermediate_child && !g_unix_open_pipe (child_pid_report_pipe, pipe_flags, error))
goto cleanup_and_fail;
@ -1943,7 +1971,7 @@ fork_exec_with_fds (gboolean intermediate_child,
*/
close_and_invalidate (&child_err_report_pipe[0]);
close_and_invalidate (&child_pid_report_pipe[0]);
if (child_close_fds != NULL)
if (child_close_fds[0] != -1)
{
int i = -1;
while (child_close_fds[++i] != -1)
@ -2049,8 +2077,7 @@ fork_exec_with_fds (gboolean intermediate_child,
else if (errno == ECHILD)
; /* do nothing, child already reaped */
else
g_warning ("waitpid() should not fail in "
"'fork_exec_with_pipes'");
g_warning ("waitpid() should not fail in 'fork_exec'");
}
}
@ -2152,9 +2179,26 @@ fork_exec_with_fds (gboolean intermediate_child,
if (child_pid)
*child_pid = pid;
return TRUE;
goto success;
}
success:
/* Close the uncared-about ends of the pipes */
close_and_invalidate (&stdin_pipe[0]);
close_and_invalidate (&stdout_pipe[1]);
close_and_invalidate (&stderr_pipe[1]);
if (stdin_pipe_out != NULL)
*stdin_pipe_out = steal_fd (&stdin_pipe[1]);
if (stdout_pipe_out != NULL)
*stdout_pipe_out = steal_fd (&stdout_pipe[0]);
if (stderr_pipe_out != NULL)
*stderr_pipe_out = steal_fd (&stderr_pipe[0]);
return TRUE;
cleanup_and_fail:
/* There was an error from the Child, reap the child to avoid it being
@ -2171,104 +2215,10 @@ fork_exec_with_fds (gboolean intermediate_child,
else if (errno == ECHILD)
; /* do nothing, child already reaped */
else
g_warning ("waitpid() should not fail in "
"'fork_exec_with_pipes'");
g_warning ("waitpid() should not fail in 'fork_exec'");
}
}
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]);
g_free (search_path_buffer_heap);
g_free (argv_buffer_heap);
return FALSE;
}
static gboolean
fork_exec_with_pipes (gboolean intermediate_child,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
gboolean cloexec_pipes,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *standard_input,
gint *standard_output,
gint *standard_error,
GError **error)
{
guint pipe_flags = cloexec_pipes ? FD_CLOEXEC : 0;
gint stdin_pipe[2] = { -1, -1 };
gint stdout_pipe[2] = { -1, -1 };
gint stderr_pipe[2] = { -1, -1 };
gint child_close_fds[4];
gboolean ret;
if (standard_input && !g_unix_open_pipe (stdin_pipe, pipe_flags, error))
goto cleanup_and_fail;
if (standard_output && !g_unix_open_pipe (stdout_pipe, pipe_flags, error))
goto cleanup_and_fail;
if (standard_error && !g_unix_open_pipe (stderr_pipe, FD_CLOEXEC, error))
goto cleanup_and_fail;
child_close_fds[0] = stdin_pipe[1];
child_close_fds[1] = stdout_pipe[0];
child_close_fds[2] = stderr_pipe[0];
child_close_fds[3] = -1;
ret = fork_exec_with_fds (intermediate_child,
working_directory,
argv,
envp,
close_descriptors,
search_path,
search_path_from_envp,
stdout_to_null,
stderr_to_null,
child_inherits_stdin,
file_and_argv_zero,
pipe_flags,
child_setup,
user_data,
child_pid,
child_close_fds,
stdin_pipe[0],
stdout_pipe[1],
stderr_pipe[1],
error);
if (!ret)
goto cleanup_and_fail;
/* Close the uncared-about ends of the pipes */
close_and_invalidate (&stdin_pipe[0]);
close_and_invalidate (&stdout_pipe[1]);
close_and_invalidate (&stderr_pipe[1]);
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:
close_and_invalidate (&stdin_pipe[0]);
close_and_invalidate (&stdin_pipe[1]);
close_and_invalidate (&stdout_pipe[0]);
@ -2276,6 +2226,14 @@ cleanup_and_fail:
close_and_invalidate (&stderr_pipe[0]);
close_and_invalidate (&stderr_pipe[1]);
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]);
g_clear_pointer (&search_path_buffer_heap, g_free);
g_clear_pointer (&argv_buffer_heap, g_free);
return FALSE;
}