slang/slsignal.c

   1 /* Copyright (c) 1998, 1999, 2001, 2002 John E. Davis
   2  * This file is part of the S-Lang library.
   3  *
   4  * You may distribute under the terms of either the GNU General Public
   5  * License or the Perl Artistic License.
   6  */
   7 #include "slinclud.h"
   8
   9 #include <signal.h>
  10
  11 #ifdef HAVE_SYS_TYPES_H
  12 # include <sys/types.h>
  13 #endif
  14 #ifdef HAVE_SYS_WAIT_H
  15 # include <sys/wait.h>
  16 #endif
  17
  18 #include <errno.h>
  19
  20 #include "slang.h"
  21 #include "_slang.h"
  22
  23 /* Do not trust these environments */
  24 #if defined(__CYGWIN32__) || defined(__MINGW32__) || defined(AMIGA)
  25 # ifdef SLANG_POSIX_SIGNALS
  26 #  undef SLANG_POSIX_SIGNALS
  27 # endif
  28 #endif
  29
  30 /* This function will cause system calls to be restarted after signal if possible */
  31 SLSig_Fun_Type *SLsignal (int sig, SLSig_Fun_Type *f)
  32 {
  33 #if defined(SLANG_POSIX_SIGNALS)
  34    struct sigaction old_sa, new_sa;
  35
  36 # ifdef SIGALRM
  37    /* We want system calls to be interrupted by SIGALRM. */
  38    if (sig == SIGALRM) return SLsignal_intr (sig, f);
  39 # endif
  40
  41    sigemptyset (&new_sa.sa_mask);
  42    new_sa.sa_handler = f;
  43
  44    new_sa.sa_flags = 0;
  45 # ifdef SA_RESTART
  46    new_sa.sa_flags |= SA_RESTART;
  47 # endif
  48
  49    if (-1 == sigaction (sig, &new_sa, &old_sa))
  50      return (SLSig_Fun_Type *) SIG_ERR;
  51
  52    return old_sa.sa_handler;
  53 #else
  54    /* Not POSIX. */
  55    return signal (sig, f);
  56 #endif
  57 }
  58
  59 /* This function will NOT cause system calls to be restarted after
  60  * signal if possible
  61  */
  62 SLSig_Fun_Type *SLsignal_intr (int sig, SLSig_Fun_Type *f)
  63 {
  64 #ifdef SLANG_POSIX_SIGNALS
  65    struct sigaction old_sa, new_sa;
  66
  67    sigemptyset (&new_sa.sa_mask);
  68    new_sa.sa_handler = f;
  69
  70    new_sa.sa_flags = 0;
  71 # ifdef SA_INTERRUPT
  72    new_sa.sa_flags |= SA_INTERRUPT;
  73 # endif
  74
  75    if (-1 == sigaction (sig, &new_sa, &old_sa))
  76      return (SLSig_Fun_Type *) SIG_ERR;
  77
  78    return old_sa.sa_handler;
  79 #else
  80    /* Not POSIX. */
  81    return signal (sig, f);
  82 #endif
  83 }
  84
  85 /* We are primarily interested in blocking signals that would cause the
  86  * application to reset the tty.  These include suspend signals and
  87  * possibly interrupt signals.
  88  */
  89 #ifdef SLANG_POSIX_SIGNALS
  90 static sigset_t Old_Signal_Mask;
  91 #endif
  92
  93 static volatile unsigned int Blocked_Depth;
  94
  95 int SLsig_block_signals (void)
  96 {
  97 #ifdef SLANG_POSIX_SIGNALS
  98    sigset_t new_mask;
  99 #endif
 100
 101    Blocked_Depth++;
 102    if (Blocked_Depth != 1)
 103      {
 104         return 0;
 105      }
 106
 107 #ifdef SLANG_POSIX_SIGNALS
 108    sigemptyset (&new_mask);
 109 # ifdef SIGQUIT
 110    sigaddset (&new_mask, SIGQUIT);
 111 # endif
 112 # ifdef SIGTSTP
 113    sigaddset (&new_mask, SIGTSTP);
 114 # endif
 115 # ifdef SIGINT
 116    sigaddset (&new_mask, SIGINT);
 117 # endif
 118 # ifdef SIGTTIN
 119    sigaddset (&new_mask, SIGTTIN);
 120 # endif
 121 # ifdef SIGTTOU
 122    sigaddset (&new_mask, SIGTTOU);
 123 # endif
 124 # ifdef SIGWINCH
 125    sigaddset (&new_mask, SIGWINCH);
 126 # endif
 127
 128    (void) sigprocmask (SIG_BLOCK, &new_mask, &Old_Signal_Mask);
 129    return 0;
 130 #else
 131    /* Not implemented. */
 132    return -1;
 133 #endif
 134 }
 135
 136 int SLsig_unblock_signals (void)
 137 {
 138    if (Blocked_Depth == 0)
 139      return -1;
 140
 141    Blocked_Depth--;
 142
 143    if (Blocked_Depth != 0)
 144      return 0;
 145
 146 #ifdef SLANG_POSIX_SIGNALS
 147    (void) sigprocmask (SIG_SETMASK, &Old_Signal_Mask, NULL);
 148    return 0;
 149 #else
 150    return -1;
 151 #endif
 152 }
 153
 154 #ifdef MSWINDOWS
 155 int SLsystem (char *cmd)
 156 {
 157    SLang_verror (SL_NOT_IMPLEMENTED, "system not implemented");
 158    return -1;
 159 }
 160
 161 #else
 162 int SLsystem (char *cmd)
 163 {
 164 #ifdef SLANG_POSIX_SIGNALS
 165    pid_t pid;
 166    int status;
 167    struct sigaction ignore;
 168 # ifdef SIGINT
 169    struct sigaction save_intr;
 170 # endif
 171 # ifdef SIGQUIT
 172    struct sigaction save_quit;
 173 # endif
 174 # ifdef SIGCHLD
 175    sigset_t child_mask, save_mask;
 176 # endif
 177
 178    if (cmd == NULL) return 1;
 179
 180    ignore.sa_handler = SIG_IGN;
 181    sigemptyset (&ignore.sa_mask);
 182    ignore.sa_flags = 0;
 183
 184 # ifdef SIGINT
 185    if (-1 == sigaction (SIGINT, &ignore, &save_intr))
 186      return -1;
 187 # endif
 188
 189 # ifdef SIGQUIT
 190    if (-1 == sigaction (SIGQUIT, &ignore, &save_quit))
 191      {
 192         (void) sigaction (SIGINT, &save_intr, NULL);
 193         return -1;
 194      }
 195 # endif
 196
 197 # ifdef SIGCHLD
 198    sigemptyset (&child_mask);
 199    sigaddset (&child_mask, SIGCHLD);
 200    if (-1 == sigprocmask (SIG_BLOCK, &child_mask, &save_mask))
 201      {
 202 #  ifdef SIGINT
 203         (void) sigaction (SIGINT, &save_intr, NULL);
 204 #  endif
 205 #  ifdef SIGQUIT
 206         (void) sigaction (SIGQUIT, &save_quit, NULL);
 207 #  endif
 208         return -1;
 209      }
 210 # endif
 211
 212    pid = fork();
 213
 214    if (pid == -1)
 215      status = -1;
 216    else if (pid == 0)
 217      {
 218         /* Child */
 219 # ifdef SIGINT
 220         (void) sigaction (SIGINT, &save_intr, NULL);
 221 # endif
 222 # ifdef SIGQUIT
 223         (void) sigaction (SIGQUIT, &save_quit, NULL);
 224 # endif
 225 # ifdef SIGCHLD
 226         (void) sigprocmask (SIG_SETMASK, &save_mask, NULL);
 227 # endif
 228
 229         execl ("/bin/sh", "sh", "-c", cmd, NULL);
 230         _exit (127);
 231      }
 232    else
 233      {
 234         /* parent */
 235         while (-1 == waitpid (pid, &status, 0))
 236           {
 237 # ifdef EINTR
 238              if (errno == EINTR)
 239                continue;
 240 # endif
 241 # ifdef ERESTARTSYS
 242              if (errno == ERESTARTSYS)
 243                continue;
 244 # endif
 245              status = -1;
 246              break;
 247           }
 248      }
 249 # ifdef SIGINT
 250    if (-1 == sigaction (SIGINT, &save_intr, NULL))
 251      status = -1;
 252 # endif
 253 # ifdef SIGQUIT
 254    if (-1 == sigaction (SIGQUIT, &save_quit, NULL))
 255      status = -1;
 256 # endif
 257 # ifdef SIGCHLD
 258    if (-1 == sigprocmask (SIG_SETMASK, &save_mask, NULL))
 259      status = -1;
 260 # endif
 261
 262    return status;
 263
 264 #else                                  /* No POSIX Signals */
 265 # ifdef SIGINT
 266    void (*sint)(int);
 267 # endif
 268 # ifdef SIGQUIT
 269    void (*squit)(int);
 270 # endif
 271    int status;
 272
 273 # ifdef SIGQUIT
 274    squit = SLsignal (SIGQUIT, SIG_IGN);
 275 # endif
 276 # ifdef SIGINT
 277    sint = SLsignal (SIGINT, SIG_IGN);
 278 # endif
 279    status = system (cmd);
 280 # ifdef SIGINT
 281    SLsignal (SIGINT, sint);
 282 # endif
 283 # ifdef SIGQUIT
 284    SLsignal (SIGQUIT, squit);
 285 # endif
 286    return status;
 287 #endif                                 /* POSIX_SIGNALS */
 288 }
 289 #endif
 290
 291 #if 0
 292 #include <windows.h>
 293 static int msw_system (char *cmd)
 294 {
 295    STARTUPINFO startup_info;
 296    PROCESS_INFORMATION process_info;
 297    int status;
 298
 299    if (cmd == NULL) return -1;
 300
 301    memset ((char *) &startup_info, 0, sizeof (STARTUPINFO));
 302    startup_info.cb = sizeof(STARTUPINFO);
 303    startup_info.dwFlags = STARTF_USESHOWWINDOW;
 304    startup_info.wShowWindow = SW_SHOWDEFAULT;
 305
 306    if (FALSE == CreateProcess (NULL,
 307                                cmd,
 308                                NULL,
 309                                NULL,
 310                                FALSE,
 311                                NORMAL_PRIORITY_CLASS|CREATE_NEW_CONSOLE,
 312                                NULL,
 313                                NULL,
 314                                &startup_info,
 315                                &process_info))
 316      {
 317         SLang_verror (0, "%s: CreateProcess failed.", cmd);
 318         return -1;
 319      }
 320
 321    status = -1;
 322
 323    if (0xFFFFFFFFUL != WaitForSingleObject (process_info.hProcess, INFINITE))
 324      {
 325         DWORD exit_code;
 326
 327         if (TRUE == GetExitCodeProcess (process_info.hProcess, &exit_code))
 328           status = (int) exit_code;
 329      }
 330
 331    CloseHandle (process_info.hThread);
 332    CloseHandle (process_info.hProcess);
 333
 334    return status;
 335 }
 336 #endif