distrib/utils/more/os.c

   1 /*      $NetBSD: os.c,v 1.7 2003/10/13 14:34:25 agc Exp $       */
   2
   3 /*
   4  * Copyright (c) 1988 Mark Nudelman
   5  * Copyright (c) 1988, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <sys/cdefs.h>
  34 #ifndef lint
  35 #if 0
  36 static char sccsid[] = "@(#)os.c        8.1 (Berkeley) 6/6/93";
  37 #else
  38 __RCSID("$NetBSD: os.c,v 1.7 2003/10/13 14:34:25 agc Exp $");
  39 #endif
  40 #endif /* not lint */
  41
  42 /*
  43  * Operating system dependent routines.
  44  *
  45  * Most of the stuff in here is based on Unix, but an attempt
  46  * has been made to make things work on other operating systems.
  47  * This will sometimes result in a loss of functionality, unless
  48  * someone rewrites code specifically for the new operating system.
  49  *
  50  * The makefile provides defines to decide whether various
  51  * Unix features are present.
  52  */
  53
  54 #include <sys/param.h>
  55 #include <sys/stat.h>
  56 #include <sys/file.h>
  57 #include <signal.h>
  58 #include <setjmp.h>
  59 #include <stdio.h>
  60 #include <string.h>
  61 #include <stdlib.h>
  62 #include <unistd.h>
  63 #include <errno.h>
  64
  65 #include "less.h"
  66 #include "extern.h"
  67 #include "pathnames.h"
  68
  69 int reading;
  70
  71 static jmp_buf read_label;
  72
  73 /*
  74  * Pass the specified command to a shell to be executed.
  75  * Like plain "system()", but handles resetting terminal modes, etc.
  76  */
  77 void
  78 lsystem(cmd)
  79         char *cmd;
  80 {
  81         int inp;
  82         char cmdbuf[256];
  83         char *shell;
  84
  85         /*
  86          * Print the command which is to be executed,
  87          * unless the command starts with a "-".
  88          */
  89         if (cmd[0] == '-')
  90                 cmd++;
  91         else
  92         {
  93                 lower_left();
  94                 clear_eol();
  95                 putstr("!");
  96                 putstr(cmd);
  97                 putstr("\n");
  98         }
  99
 100         /*
 101          * De-initialize the terminal and take out of raw mode.
 102          */
 103         deinit();
 104         flush();
 105         raw_mode(0);
 106
 107         /*
 108          * Restore signals to their defaults.
 109          */
 110         init_signals(0);
 111
 112         /*
 113          * Force standard input to be the terminal, "/dev/tty",
 114          * even if less's standard input is coming from a pipe.
 115          */
 116         inp = dup(0);
 117         (void)close(0);
 118         if (open(_PATH_TTY, O_RDONLY, 0) < 0)
 119                 (void)dup(inp);
 120
 121         /*
 122          * Pass the command to the system to be executed.
 123          * If we have a SHELL environment variable, use
 124          * <$SHELL -c "command"> instead of just <command>.
 125          * If the command is empty, just invoke a shell.
 126          */
 127         if ((shell = getenv("SHELL")) != NULL && *shell != '\0')
 128         {
 129                 if (*cmd == '\0')
 130                         cmd = shell;
 131                 else
 132                 {
 133                         (void)snprintf(cmdbuf, sizeof(cmdbuf), "%s -c \"%s\"",
 134                             shell, cmd);
 135                         cmd = cmdbuf;
 136                 }
 137         }
 138         if (*cmd == '\0')
 139                 cmd = "sh";
 140
 141         (void)system(cmd);
 142
 143         /*
 144          * Restore standard input, reset signals, raw mode, etc.
 145          */
 146         (void)close(0);
 147         (void)dup(inp);
 148         (void)close(inp);
 149
 150         init_signals(1);
 151         raw_mode(1);
 152         init();
 153         screen_trashed = 1;
 154 #if defined(SIGWINCH) || defined(SIGWIND)
 155         /*
 156          * Since we were ignoring window change signals while we executed
 157          * the system command, we must assume the window changed.
 158          */
 159         winch(SIGWINCH);
 160 #endif
 161 }
 162
 163 /*
 164  * Like read() system call, but is deliberately interruptable.
 165  * A call to intread() from a signal handler will interrupt
 166  * any pending iread().
 167  */
 168 int
 169 iread(fd, buf, len)
 170         int fd;
 171         char *buf;
 172         int len;
 173 {
 174         int n;
 175
 176         if (setjmp(read_label))
 177                 /*
 178                  * We jumped here from intread.
 179                  */
 180                 return (READ_INTR);
 181
 182         flush();
 183         reading = 1;
 184         n = read(fd, buf, len);
 185         reading = 0;
 186         if (n < 0)
 187                 return (-1);
 188         return (n);
 189 }
 190
 191 void
 192 intread()
 193 {
 194         (void)sigsetmask(0L);
 195         longjmp(read_label, 1);
 196 }
 197
 198 /*
 199  * Expand a filename, substituting any environment variables, etc.
 200  * The implementation of this is necessarily very operating system
 201  * dependent.  This implementation is unabashedly only for Unix systems.
 202  */
 203 char *
 204 glob(filename)
 205         char *filename;
 206 {
 207         FILE *f;
 208         char *p;
 209         int ch;
 210         char *cmd;
 211         static char buffer[MAXPATHLEN];
 212
 213         if (filename[0] == '#')
 214                 return (filename);
 215
 216         /*
 217          * We get the shell to expand the filename for us by passing
 218          * an "echo" command to the shell and reading its output.
 219          */
 220         p = getenv("SHELL");
 221         if (p == NULL || *p == '\0')
 222         {
 223                 /*
 224                  * Read the output of <echo filename>.
 225                  */
 226                 asprintf(&cmd, "echo \"%s\"", filename);
 227                 if (cmd == NULL)
 228                         return (filename);
 229         } else
 230         {
 231                 /*
 232                  * Read the output of <$SHELL -c "echo filename">.
 233                  */
 234                 asprintf(&cmd, "%s -c \"echo %s\"", p, filename);
 235                 if (cmd == NULL)
 236                         return (filename);
 237         }
 238
 239         if ((f = popen(cmd, "r")) == NULL)
 240                 return (filename);
 241         free(cmd);
 242
 243         for (p = buffer; p < &buffer[sizeof(buffer)-1];  p++)
 244         {
 245                 if ((ch = getc(f)) == '\n' || ch == EOF)
 246                         break;
 247                 *p = ch;
 248         }
 249         *p = '\0';
 250         (void)pclose(f);
 251         return(buffer);
 252 }
 253
 254 char *
 255 bad_file(filename, message, len)
 256         char *filename, *message;
 257         u_int len;
 258 {
 259         struct stat statbuf;
 260
 261         if (stat(filename, &statbuf) < 0) {
 262                 (void)snprintf(message, len, "%s: %s", filename,
 263                     strerror(errno));
 264                 return(message);
 265         }
 266         if ((statbuf.st_mode & S_IFMT) == S_IFDIR) {
 267                 static char is_dir[] = " is a directory";
 268
 269                 strtcpy(message, filename, (int)(len-sizeof(is_dir)-1));
 270                 (void)strlcat(message, is_dir, len);
 271                 return(message);
 272         }
 273         return((char *)NULL);
 274 }
 275
 276 /*
 277  * Copy a string, truncating to the specified length if necessary.
 278  * Unlike strncpy(), the resulting string is guaranteed to be null-terminated.
 279  */
 280 void
 281 strtcpy(to, from, len)
 282         char *to, *from;
 283         int len;
 284 {
 285         (void)strncpy(to, from, (int)len);
 286         to[len-1] = '\0';
 287 }
 288