1 /*
2 * Copyright (C) 1984-2025 Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10
11 /*
12 * Routines to execute other programs.
13 * Necessarily very OS dependent.
14 */
15
16 #include "less.h"
17 #include <signal.h>
18 #include "position.h"
19
20 #if MSDOS_COMPILER
21 #include <dos.h>
22 #if MSDOS_COMPILER==WIN32C && defined(MINGW)
23 #include <direct.h>
24 #define setdisk(n) _chdrive((n)+1)
25 #else
26 #ifdef _MSC_VER
27 #include <direct.h>
28 #define setdisk(n) _chdrive((n)+1)
29 #else
30 #include <dir.h>
31 #endif
32 #endif
33 #endif
34
35 extern IFILE curr_ifile;
36
37
38 #if HAVE_SYSTEM
39
40 /*
41 * Pass the specified command to a shell to be executed.
42 * Like plain "system()", but handles resetting terminal modes, etc.
43 */
lsystem(constant char * cmd,constant char * donemsg)44 public void lsystem(constant char *cmd, constant char *donemsg)
45 {
46 int inp;
47 #if HAVE_SHELL
48 constant char *shell;
49 char *p;
50 #endif
51 IFILE save_ifile;
52 #if MSDOS_COMPILER && MSDOS_COMPILER!=WIN32C
53 char cwd[FILENAME_MAX+1];
54 #endif
55
56 /*
57 * Print the command which is to be executed,
58 * unless the command starts with a "-".
59 */
60 if (cmd[0] == '-')
61 cmd++;
62 else
63 {
64 clear_bot();
65 putstr("!");
66 putstr(cmd);
67 putstr("\n");
68 }
69
70 #if MSDOS_COMPILER
71 #if MSDOS_COMPILER==WIN32C
72 if (*cmd == '\0')
73 cmd = getenv("COMSPEC");
74 #else
75 /*
76 * Working directory is global on MSDOS.
77 * The child might change the working directory, so we
78 * must save and restore CWD across calls to "system",
79 * or else we won't find our file when we return and
80 * try to "reedit_ifile" it.
81 */
82 getcwd(cwd, FILENAME_MAX);
83 #endif
84 #endif
85
86 /*
87 * Close the current input file.
88 */
89 save_ifile = save_curr_ifile();
90 (void) edit_ifile(NULL_IFILE);
91
92 /*
93 * De-initialize the terminal and take out of raw mode.
94 */
95 deinit();
96 flush(); /* Make sure the deinit chars get out */
97 raw_mode(0);
98 #if MSDOS_COMPILER==WIN32C
99 close_getchr();
100 #endif
101
102 /*
103 * Restore signals to their defaults.
104 */
105 init_signals(0);
106
107 #if HAVE_DUP
108 /*
109 * Force standard input to be the user's terminal
110 * (the normal standard input), even if less's standard input
111 * is coming from a pipe.
112 */
113 inp = dup(0);
114 close(0);
115 #if !MSDOS_COMPILER
116 if (open_tty() < 0)
117 #endif
118 dup(inp);
119 #endif
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 HAVE_SHELL
128 p = NULL;
129 if ((shell = lgetenv("SHELL")) != NULL && *shell != '\0')
130 {
131 if (*cmd == '\0')
132 p = save(shell);
133 else
134 {
135 char *esccmd = shell_quote(cmd);
136 if (esccmd != NULL)
137 {
138 size_t len = strlen(shell) + strlen(esccmd) + 5;
139 p = (char *) ecalloc(len, sizeof(char));
140 SNPRINTF3(p, len, "%s %s %s", shell, shell_coption(), esccmd);
141 free(esccmd);
142 }
143 }
144 }
145 if (p == NULL)
146 {
147 if (*cmd == '\0')
148 p = save("sh");
149 else
150 p = save(cmd);
151 }
152 system(p);
153 free(p);
154 #else
155 #if MSDOS_COMPILER==DJGPPC
156 /*
157 * Make stdin of the child be in cooked mode.
158 */
159 setmode(0, O_TEXT);
160 /*
161 * We don't need to catch signals of the child (it
162 * also makes trouble with some DPMI servers).
163 */
164 __djgpp_exception_toggle();
165 system(cmd);
166 __djgpp_exception_toggle();
167 #else
168 system(cmd);
169 #endif
170 #endif
171
172 #if HAVE_DUP
173 /*
174 * Restore standard input, reset signals, raw mode, etc.
175 */
176 close(0);
177 dup(inp);
178 close(inp);
179 #endif
180
181 #if MSDOS_COMPILER==WIN32C
182 open_getchr();
183 #endif
184 init_signals(1);
185 raw_mode(1);
186 if (donemsg != NULL)
187 {
188 putstr(donemsg);
189 putstr(" (press RETURN)");
190 get_return();
191 putchr('\n');
192 flush();
193 }
194 init();
195 screen_trashed();
196
197 #if MSDOS_COMPILER && MSDOS_COMPILER!=WIN32C
198 /*
199 * Restore the previous directory (possibly
200 * changed by the child program we just ran).
201 */
202 chdir(cwd);
203 #if MSDOS_COMPILER != DJGPPC
204 /*
205 * Some versions of chdir() don't change to the drive
206 * which is part of CWD. (DJGPP does this in chdir.)
207 */
208 if (cwd[1] == ':')
209 {
210 if (cwd[0] >= 'a' && cwd[0] <= 'z')
211 setdisk(cwd[0] - 'a');
212 else if (cwd[0] >= 'A' && cwd[0] <= 'Z')
213 setdisk(cwd[0] - 'A');
214 }
215 #endif
216 #endif
217
218 /*
219 * Reopen the current input file.
220 */
221 reedit_ifile(save_ifile);
222
223 #if defined(SIGWINCH) || defined(SIGWIND)
224 /*
225 * Since we were ignoring window change signals while we executed
226 * the system command, we must assume the window changed.
227 * Warning: this leaves a signal pending (in "sigs"),
228 * so psignals() should be called soon after lsystem().
229 */
230 winch(0);
231 #endif
232 }
233
234 #endif
235
236 #if PIPEC
237
238 /*
239 * Pipe a section of the input file into the given shell command.
240 * The section to be piped is the section "between" the current
241 * position and the position marked by the given letter.
242 *
243 * If the mark is after the current screen, the section between
244 * the top line displayed and the mark is piped.
245 * If the mark is before the current screen, the section between
246 * the mark and the bottom line displayed is piped.
247 * If the mark is on the current screen, or if the mark is ".",
248 * the whole current screen is piped.
249 */
pipe_mark(char c,constant char * cmd)250 public int pipe_mark(char c, constant char *cmd)
251 {
252 POSITION mpos, tpos, bpos;
253
254 /*
255 * mpos = the marked position.
256 * tpos = top of screen.
257 * bpos = bottom of screen.
258 */
259 mpos = markpos(c);
260 if (mpos == NULL_POSITION)
261 return (-1);
262 tpos = position(TOP);
263 if (tpos == NULL_POSITION)
264 tpos = ch_zero();
265 bpos = position(BOTTOM);
266
267 if (c == '.')
268 return (pipe_data(cmd, tpos, bpos));
269 else if (mpos <= tpos)
270 return (pipe_data(cmd, mpos, bpos));
271 else if (bpos == NULL_POSITION)
272 return (pipe_data(cmd, tpos, bpos));
273 else
274 return (pipe_data(cmd, tpos, mpos));
275 }
276
277 /*
278 * Create a pipe to the given shell command.
279 * Feed it the file contents between the positions spos and epos.
280 */
pipe_data(constant char * cmd,POSITION spos,POSITION epos)281 public int pipe_data(constant char *cmd, POSITION spos, POSITION epos)
282 {
283 FILE *f;
284 int c;
285
286 /*
287 * This is structured much like lsystem().
288 * Since we're running a shell program, we must be careful
289 * to perform the necessary deinitialization before running
290 * the command, and reinitialization after it.
291 */
292 if (ch_seek(spos) != 0)
293 {
294 error("Cannot seek to start position", NULL_PARG);
295 return (-1);
296 }
297
298 if ((f = popen(cmd, "w")) == NULL)
299 {
300 error("Cannot create pipe", NULL_PARG);
301 return (-1);
302 }
303 clear_bot();
304 putstr("!");
305 putstr(cmd);
306 putstr("\n");
307
308 deinit();
309 flush();
310 raw_mode(0);
311 init_signals(0);
312 #if MSDOS_COMPILER==WIN32C
313 close_getchr();
314 #endif
315 #ifdef SIGPIPE
316 LSIGNAL(SIGPIPE, SIG_IGN);
317 #endif
318
319 c = EOI;
320 while (epos == NULL_POSITION || spos++ <= epos)
321 {
322 /*
323 * Read a character from the file and give it to the pipe.
324 */
325 c = ch_forw_get();
326 if (c == EOI)
327 break;
328 if (putc(c, f) == EOF)
329 break;
330 }
331
332 /*
333 * Finish up the last line.
334 */
335 while (c != '\n' && c != EOI )
336 {
337 c = ch_forw_get();
338 if (c == EOI)
339 break;
340 if (putc(c, f) == EOF)
341 break;
342 }
343
344 pclose(f);
345
346 #ifdef SIGPIPE
347 LSIGNAL(SIGPIPE, SIG_DFL);
348 #endif
349 #if MSDOS_COMPILER==WIN32C
350 open_getchr();
351 #endif
352 init_signals(1);
353 raw_mode(1);
354 init();
355 screen_trashed();
356 #if defined(SIGWINCH) || defined(SIGWIND)
357 /* {{ Probably don't need this here. }} */
358 winch(0);
359 #endif
360 return (0);
361 }
362
363 #endif
364