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Factor start_child out of open_process

* libguile/posix.c (start_child): Factor out from open_process.  Based
  on initial work by Eli Zaretskii.
This commit is contained in:
Andy Wingo 2016-07-11 22:46:55 +02:00
parent f632d45c69
commit 10ae9cc601

View file

@ -1236,71 +1236,21 @@ SCM_DEFINE (scm_fork, "primitive-fork", 0, 0, 0,
return scm_from_int (pid);
}
#undef FUNC_NAME
#endif /* HAVE_FORK */
#ifdef HAVE_FORK
#define HAVE_START_CHILD 1
/* Since Guile uses threads, we have to be very careful to avoid calling
functions that are not async-signal-safe in the child. That's why
this function is implemented in C. */
static SCM
scm_open_process (SCM mode, SCM prog, SCM args)
#define FUNC_NAME "open-process"
static pid_t
start_child (const char *exec_file, char **exec_argv,
int reading, int c2p[2], int writing, int p2c[2],
int in, int out, int err)
{
long mode_bits;
int reading, writing;
int c2p[2]; /* Child to parent. */
int p2c[2]; /* Parent to child. */
int in = -1, out = -1, err = -1;
int pid;
char *exec_file;
char **exec_argv;
int max_fd = 1024;
exec_file = scm_to_locale_string (prog);
exec_argv = scm_i_allocate_string_pointers (scm_cons (prog, args));
mode_bits = scm_i_mode_bits (mode);
reading = mode_bits & SCM_RDNG;
writing = mode_bits & SCM_WRTNG;
if (reading)
{
if (pipe (c2p))
{
int errno_save = errno;
free (exec_file);
errno = errno_save;
SCM_SYSERROR;
}
out = c2p[1];
}
if (writing)
{
if (pipe (p2c))
{
int errno_save = errno;
free (exec_file);
if (reading)
{
close (c2p[0]);
close (c2p[1]);
}
errno = errno_save;
SCM_SYSERROR;
}
in = p2c[0];
}
{
SCM port;
if (SCM_OPOUTFPORTP ((port = scm_current_error_port ())))
err = SCM_FPORT_FDES (port);
if (out == -1 && SCM_OPOUTFPORTP ((port = scm_current_output_port ())))
out = SCM_FPORT_FDES (port);
if (in == -1 && SCM_OPINFPORTP ((port = scm_current_input_port ())))
in = SCM_FPORT_FDES (port);
}
#if defined (HAVE_GETRLIMIT) && defined (RLIMIT_NOFILE)
{
struct rlimit lim = { 0, 0 };
@ -1311,44 +1261,10 @@ scm_open_process (SCM mode, SCM prog, SCM args)
pid = fork ();
if (pid == -1)
{
int errno_save = errno;
free (exec_file);
if (reading)
{
close (c2p[0]);
close (c2p[1]);
}
if (writing)
{
close (p2c[0]);
close (p2c[1]);
}
errno = errno_save;
SCM_SYSERROR;
}
if (pid)
/* Parent. */
{
SCM read_port = SCM_BOOL_F, write_port = SCM_BOOL_F;
/* There is no sense in catching errors on close(). */
if (reading)
{
close (c2p[1]);
read_port = scm_fdes_to_port (c2p[0], "r0", sym_read_pipe);
}
if (writing)
{
close (p2c[0]);
write_port = scm_fdes_to_port (p2c[1], "w0", sym_write_pipe);
}
return scm_values
(scm_list_3 (read_port, write_port, scm_from_int (pid)));
}
if (pid != 0)
/* The parent, with either and error (pid == -1), or the PID of the
child. Return directly in either case. */
return pid;
/* The child. */
if (reading)
@ -1398,16 +1314,118 @@ scm_open_process (SCM mode, SCM prog, SCM args)
if (err > 0)
{
char *msg = strerror (errno);
fprintf (fdopen (err, "a"), "In execlp of %s: %s\n",
fprintf (fdopen (err, "a"), "In execvp of %s: %s\n",
exec_file, msg);
}
_exit (EXIT_FAILURE);
/* Not reached. */
return SCM_BOOL_F;
return -1;
}
#endif
#ifdef HAVE_START_CHILD
static SCM
scm_open_process (SCM mode, SCM prog, SCM args)
#define FUNC_NAME "open-process"
{
long mode_bits;
int reading, writing;
int c2p[2]; /* Child to parent. */
int p2c[2]; /* Parent to child. */
int in = -1, out = -1, err = -1;
int pid;
char *exec_file;
char **exec_argv;
SCM read_port = SCM_BOOL_F, write_port = SCM_BOOL_F;
exec_file = scm_to_locale_string (prog);
exec_argv = scm_i_allocate_string_pointers (scm_cons (prog, args));
mode_bits = scm_i_mode_bits (mode);
reading = mode_bits & SCM_RDNG;
writing = mode_bits & SCM_WRTNG;
if (reading)
{
if (pipe (c2p))
{
int errno_save = errno;
free (exec_file);
errno = errno_save;
SCM_SYSERROR;
}
out = c2p[1];
}
if (writing)
{
if (pipe (p2c))
{
int errno_save = errno;
free (exec_file);
if (reading)
{
close (c2p[0]);
close (c2p[1]);
}
errno = errno_save;
SCM_SYSERROR;
}
in = p2c[0];
}
{
SCM port;
if (SCM_OPOUTFPORTP ((port = scm_current_error_port ())))
err = SCM_FPORT_FDES (port);
if (out == -1 && SCM_OPOUTFPORTP ((port = scm_current_output_port ())))
out = SCM_FPORT_FDES (port);
if (in == -1 && SCM_OPINFPORTP ((port = scm_current_input_port ())))
in = SCM_FPORT_FDES (port);
}
pid = start_child (exec_file, exec_argv, reading, c2p, writing, p2c,
in, out, err);
if (pid == -1)
{
int errno_save = errno;
free (exec_file);
if (reading)
{
close (c2p[0]);
close (c2p[1]);
}
if (writing)
{
close (p2c[0]);
close (p2c[1]);
}
errno = errno_save;
SCM_SYSERROR;
}
/* There is no sense in catching errors on close(). */
if (reading)
{
close (c2p[1]);
read_port = scm_fdes_to_port (c2p[0], "r0", sym_read_pipe);
}
if (writing)
{
close (p2c[0]);
write_port = scm_fdes_to_port (p2c[1], "w0", sym_write_pipe);
}
return scm_values (scm_list_3 (read_port,
write_port,
scm_from_int (pid)));
}
#undef FUNC_NAME
#endif /* HAVE_FORK */
#endif /* HAVE_START_CHILD */
#ifdef __MINGW32__
# include "win32-uname.h"
@ -2215,13 +2233,13 @@ SCM_DEFINE (scm_gethostname, "gethostname", 0, 0, 0,
#endif /* HAVE_GETHOSTNAME */
#ifdef HAVE_FORK
#ifdef HAVE_START_CHILD
static void
scm_init_popen (void)
{
scm_c_define_gsubr ("open-process", 2, 0, 1, scm_open_process);
}
#endif
#endif /* HAVE_START_CHILD */
void
scm_init_posix ()
@ -2320,11 +2338,13 @@ scm_init_posix ()
#ifdef HAVE_FORK
scm_add_feature ("fork");
#endif /* HAVE_FORK */
#ifdef HAVE_START_CHILD
scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
"scm_init_popen",
(scm_t_extension_init_func) scm_init_popen,
NULL);
#endif /* HAVE_FORK */
#endif /* HAVE_START_CHILD */
}
/*