diff options
Diffstat (limited to 'libguile/posix.c')
| -rw-r--r-- | libguile/posix.c | 156 |
1 files changed, 154 insertions, 2 deletions
diff --git a/libguile/posix.c b/libguile/posix.c index b5352c2c4..0e6a38f33 100644 --- a/libguile/posix.c +++ b/libguile/posix.c @@ -1,4 +1,4 @@ -/* Copyright 1995-2014, 2016-2019, 2021-2022 +/* Copyright 1995-2014, 2016-2019, 2021-2023 Free Software Foundation, Inc. Copyright 2021 Maxime Devos <maximedevos@telenet.be> @@ -33,6 +33,7 @@ #include <sys/types.h> #include <uniconv.h> #include <unistd.h> +#include <spawn.h> #ifdef HAVE_SCHED_H # include <sched.h> @@ -63,6 +64,7 @@ #include "fports.h" #include "gettext.h" #include "gsubr.h" +#include "keywords.h" #include "list.h" #include "modules.h" #include "numbers.h" @@ -1426,6 +1428,156 @@ start_child (const char *exec_file, char **exec_argv, } #endif +static pid_t +do_spawn (char *exec_file, char **exec_argv, char **exec_env, + int in, int out, int err, int spawnp) +{ + pid_t pid = -1; + + posix_spawn_file_actions_t actions; + posix_spawnattr_t *attrp = NULL; + + int max_fd = 1024; + +#if defined (HAVE_GETRLIMIT) && defined (RLIMIT_NOFILE) + { + struct rlimit lim = { 0, 0 }; + if (getrlimit (RLIMIT_NOFILE, &lim) == 0) + max_fd = lim.rlim_cur; + } +#endif + + posix_spawn_file_actions_init (&actions); + + int free_fd_slots = 0; + int fd_slot[3]; + + for (int fdnum = 3;free_fd_slots < 3 && fdnum < max_fd;fdnum++) + { + if (fdnum != in && fdnum != out && fdnum != err) + { + fd_slot[free_fd_slots] = fdnum; + free_fd_slots++; + } + } + + /* Move the fds out of the way, so that duplicate fds or fds equal + to 0, 1, 2 don't trample each other */ + + posix_spawn_file_actions_adddup2 (&actions, in, fd_slot[0]); + posix_spawn_file_actions_adddup2 (&actions, out, fd_slot[1]); + posix_spawn_file_actions_adddup2 (&actions, err, fd_slot[2]); + posix_spawn_file_actions_adddup2 (&actions, fd_slot[0], 0); + posix_spawn_file_actions_adddup2 (&actions, fd_slot[1], 1); + posix_spawn_file_actions_adddup2 (&actions, fd_slot[2], 2); + + while (--max_fd > 2) + posix_spawn_file_actions_addclose (&actions, max_fd); + + int res = -1; + if (spawnp) + res = posix_spawnp (&pid, exec_file, &actions, attrp, + exec_argv, exec_env); + else + res = posix_spawn (&pid, exec_file, &actions, attrp, + exec_argv, exec_env); + if (res != 0) + return -1; + + return pid; +} + +SCM_KEYWORD (kw_environment, "environment"); +SCM_KEYWORD (kw_input, "input"); +SCM_KEYWORD (kw_output, "output"); +SCM_KEYWORD (kw_error, "error"); +SCM_KEYWORD (kw_search_path, "search-path?"); + +SCM_DEFINE (scm_spawn_process, "spawn", 2, 0, 1, + (SCM program, SCM arguments, SCM keyword_args), + "Spawn a new child process executing @var{program} with the\n" + "given @var{arguments}, a list of one or more strings (by\n" + "convention, the first argument is typically @var{program}),\n" + "and return its PID. Raise a @code{system-error} exception if\n" + "@var{program} could not be found or could not be executed.\n\n" + "If the keyword argument @code{#:search-path?} is true, it\n" + "selects whether the @env{PATH} environment variable should be\n" + "inspected to find @var{program}. It is true by default.\n\n" + "The @code{#:environment} keyword parameter specifies the\n" + "list of environment variables of the child process. It\n" + "defaults to @code{(environ)}.\n\n" + "The keyword arguments @code{#:input}, @code{#:output}, and\n" + "@code{#:error} specify the port or file descriptor for the\n" + "child process to use as standard input, standard output, and\n" + "standard error. No other file descriptors are inherited\n" + "from the parent process.\n") +#define FUNC_NAME s_scm_spawn_process +{ + SCM env, in_scm, out_scm, err_scm, use_path; + int pid = -1; + char *exec_file, **exec_argv, **exec_env; + int in, out, err; + + /* In theory 'exec' accepts zero arguments, but programs are typically + not prepared for that and POSIX says: "The value in argv[0] should + point to a filename string that is associated with the process + image being started" (see + <https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_spawn.html>). */ + SCM_VALIDATE_NONEMPTYLIST (1, arguments); + + env = SCM_UNDEFINED; + in_scm = SCM_UNDEFINED; + out_scm = SCM_UNDEFINED; + err_scm = SCM_UNDEFINED; + use_path = SCM_BOOL_T; + + scm_c_bind_keyword_arguments (FUNC_NAME, keyword_args, 0, + kw_environment, &env, + kw_input, &in_scm, + kw_output, &out_scm, + kw_error, &err_scm, + kw_search_path, &use_path, + SCM_UNDEFINED); + + scm_dynwind_begin (0); + + exec_file = scm_to_locale_string (program); + scm_dynwind_free (exec_file); + + exec_argv = scm_i_allocate_string_pointers (arguments); + + if (SCM_UNBNDP (env)) + exec_env = environ; + else + exec_env = scm_i_allocate_string_pointers (env); + + if (SCM_UNBNDP (in_scm)) + in_scm = scm_current_input_port (); + if (SCM_UNBNDP (out_scm)) + out_scm = scm_current_output_port (); + if (SCM_UNBNDP (err_scm)) + err_scm = scm_current_error_port (); + +#define FDES_FROM_PORT_OR_INTEGER(obj) \ + (scm_is_integer (obj) ? scm_to_int (obj) : SCM_FPORT_FDES (obj)) + + in = FDES_FROM_PORT_OR_INTEGER (in_scm); + out = FDES_FROM_PORT_OR_INTEGER (out_scm); + err = FDES_FROM_PORT_OR_INTEGER (err_scm); + +#undef FDES_FROM_PORT_OR_INTEGER + + pid = do_spawn (exec_file, exec_argv, exec_env, + in, out, err, scm_to_bool (use_path)); + if (pid == -1) + SCM_SYSERROR; + + scm_dynwind_end (); + + return scm_from_int (pid); +} +#undef FUNC_NAME + #ifdef HAVE_START_CHILD static SCM scm_piped_process (SCM prog, SCM args, SCM from, SCM to) @@ -2547,5 +2699,5 @@ scm_init_posix () "scm_init_popen", (scm_t_extension_init_func) scm_init_popen, NULL); -#endif /* HAVE_START_CHILD */ +#endif /* HAVE_FORK */ } |