libguile/simpos.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003, 2004, 2009 Free Software
   2  * Foundation, Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19
  20 \f
  21 #ifdef HAVE_CONFIG_H
  22 #  include <config.h>
  23 #endif
  24
  25 #include <errno.h>
  26 #include <signal.h>  /* for SIG constants */
  27 #include <stdlib.h>  /* for getenv */
  28
  29 #include "libguile/_scm.h"
  30
  31 #include "libguile/scmsigs.h"
  32 #include "libguile/strings.h"
  33
  34 #include "libguile/validate.h"
  35 #include "libguile/simpos.h"
  36 #include "libguile/dynwind.h"
  37
  38 #ifdef HAVE_STRING_H
  39 #include <string.h>
  40 #endif
  41 #ifdef HAVE_UNISTD_H
  42 #include <unistd.h>
  43 #endif
  44 #if HAVE_SYS_WAIT_H
  45 # include <sys/wait.h>
  46 #endif
  47
  48 #include "posix.h"
  49
  50 \f
  51 extern int system();
  52 \f
  53
  54 #ifdef HAVE_SYSTEM
  55 SCM_DEFINE (scm_system, "system", 0, 1, 0,
  56            (SCM cmd),
  57             "Execute @var{cmd} using the operating system's \"command\n"
  58             "processor\".  Under Unix this is usually the default shell\n"
  59             "@code{sh}.  The value returned is @var{cmd}'s exit status as\n"
  60             "returned by @code{waitpid}, which can be interpreted using\n"
  61             "@code{status:exit-val} and friends.\n"
  62             "\n"
  63             "If @code{system} is called without arguments, return a boolean\n"
  64             "indicating whether the command processor is available.")
  65 #define FUNC_NAME s_scm_system
  66 {
  67   int rv, eno;
  68   char *c_cmd;
  69
  70   if (SCM_UNBNDP (cmd))
  71     {
  72       rv = system (NULL);
  73       return scm_from_bool(rv);
  74     }
  75   SCM_VALIDATE_STRING (1, cmd);
  76   errno = 0;
  77   c_cmd = scm_to_locale_string (cmd);
  78   rv = system (c_cmd);
  79   eno = errno; free (c_cmd); errno = eno;
  80   if (rv == -1 || (rv == 127 && errno != 0))
  81     SCM_SYSERROR;
  82   return scm_from_int (rv);
  83 }
  84 #undef FUNC_NAME
  85 #endif /* HAVE_SYSTEM */
  86
  87
  88 #ifdef HAVE_SYSTEM
  89 #ifdef HAVE_WAITPID
  90
  91
  92 SCM_DEFINE (scm_system_star, "system*", 0, 0, 1,
  93            (SCM args),
  94 "Execute the command indicated by @var{args}.  The first element must\n"
  95 "be a string indicating the command to be executed, and the remaining\n"
  96 "items must be strings representing each of the arguments to that\n"
  97 "command.\n"
  98 "\n"
  99 "This function returns the exit status of the command as provided by\n"
 100 "@code{waitpid}.  This value can be handled with @code{status:exit-val}\n"
 101 "and the related functions.\n"
 102 "\n"
 103 "@code{system*} is similar to @code{system}, but accepts only one\n"
 104 "string per-argument, and performs no shell interpretation.  The\n"
 105 "command is executed using fork and execlp.  Accordingly this function\n"
 106 "may be safer than @code{system} in situations where shell\n"
 107 "interpretation is not required.\n"
 108 "\n"
 109 "Example: (system* \"echo\" \"foo\" \"bar\")")
 110 #define FUNC_NAME s_scm_system_star
 111 {
 112   if (scm_is_null (args))
 113     SCM_WRONG_NUM_ARGS ();
 114
 115   if (scm_is_pair (args))
 116     {
 117       SCM oldint;
 118       SCM oldquit;
 119       SCM sig_ign;
 120       SCM sigint;
 121       SCM sigquit;
 122       int pid;
 123       char **execargv;
 124
 125       /* allocate before fork */
 126       execargv = scm_i_allocate_string_pointers (args);
 127
 128       /* make sure the child can't kill us (as per normal system call) */
 129       sig_ign = scm_from_long ((unsigned long) SIG_IGN);
 130       sigint = scm_from_int (SIGINT);
 131       sigquit = scm_from_int (SIGQUIT);
 132       oldint = scm_sigaction (sigint, sig_ign, SCM_UNDEFINED);
 133       oldquit = scm_sigaction (sigquit, sig_ign, SCM_UNDEFINED);
 134
 135       pid = fork ();
 136       if (pid == 0)
 137         {
 138           /* child */
 139           execvp (execargv[0], execargv);
 140           SCM_SYSERROR;
 141           /* not reached.  */
 142           return SCM_BOOL_F;
 143         }
 144       else
 145         {
 146           /* parent */
 147           int wait_result, status;
 148
 149           if (pid == -1)
 150             SCM_SYSERROR;
 151
 152           SCM_SYSCALL (wait_result = waitpid (pid, &status, 0));
 153           if (wait_result == -1)
 154             SCM_SYSERROR;
 155           scm_sigaction (sigint, SCM_CAR (oldint), SCM_CDR (oldint));
 156           scm_sigaction (sigquit, SCM_CAR (oldquit), SCM_CDR (oldquit));
 157
 158           return scm_from_int (status);
 159         }
 160     }
 161   else
 162     SCM_WRONG_TYPE_ARG (1, args);
 163 }
 164 #undef FUNC_NAME
 165 #endif /* HAVE_WAITPID */
 166 #endif /* HAVE_SYSTEM */
 167
 168
 169 SCM_DEFINE (scm_getenv, "getenv", 1, 0, 0,
 170             (SCM nam),
 171             "Looks up the string @var{name} in the current environment.  The return\n"
 172             "value is @code{#f} unless a string of the form @code{NAME=VALUE} is\n"
 173             "found, in which case the string @code{VALUE} is returned.")
 174 #define FUNC_NAME s_scm_getenv
 175 {
 176   char *val;
 177   char *var = scm_to_locale_string (nam);
 178   val = getenv (var);
 179   free (var);
 180   return val ? scm_from_locale_string (val) : SCM_BOOL_F;
 181 }
 182 #undef FUNC_NAME
 183
 184 /* simple exit, without unwinding the scheme stack or flushing ports.  */
 185 SCM_DEFINE (scm_primitive_exit, "primitive-exit", 0, 1, 0,
 186             (SCM status),
 187             "Terminate the current process without unwinding the Scheme\n"
 188             "stack.  The exit status is @var{status} if supplied, otherwise\n"
 189             "zero.")
 190 #define FUNC_NAME s_scm_primitive_exit
 191 {
 192   int cstatus = 0;
 193   if (!SCM_UNBNDP (status))
 194     cstatus = scm_to_int (status);
 195   exit (cstatus);
 196 }
 197 #undef FUNC_NAME
 198
 199 SCM_DEFINE (scm_primitive__exit, "primitive-_exit", 0, 1, 0,
 200             (SCM status),
 201             "Terminate the current process using the _exit() system call and\n"
 202             "without unwinding the Scheme stack.  The exit status is\n"
 203             "@var{status} if supplied, otherwise zero.\n"
 204             "\n"
 205             "This function is typically useful after a fork, to ensure no\n"
 206             "Scheme cleanups or @code{atexit} handlers are run (those\n"
 207             "usually belonging in the parent rather than the child).")
 208 #define FUNC_NAME s_scm_primitive__exit
 209 {
 210   int cstatus = 0;
 211   if (!SCM_UNBNDP (status))
 212     cstatus = scm_to_int (status);
 213   _exit (cstatus);
 214 }
 215 #undef FUNC_NAME
 216
 217
 218
 219 void
 220 scm_init_simpos ()
 221 {
 222 #include "libguile/simpos.x"
 223 }
 224
 225
 226 /*
 227   Local Variables:
 228   c-file-style: "gnu"
 229   End:
 230 */