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(__MINGW32__)
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 int sigs;
36 extern IFILE curr_ifile;
37
38
39 #if HAVE_SYSTEM
40
41 /*
42 * Pass the specified command to a shell to be executed.
43 * Like plain "system()", but handles resetting terminal modes, etc.
44 */
lsystem(constant char * cmd,constant char * donemsg)45 public void lsystem(constant char *cmd, constant char *donemsg)
46 {
47 int inp;
48 #if HAVE_SHELL
49 constant char *shell;
50 char *p;
51 #endif
52 IFILE save_ifile;
53 #if MSDOS_COMPILER && MSDOS_COMPILER!=WIN32C
54 char cwd[FILENAME_MAX+1];
55 #endif
56
57 /*
58 * Print the command which is to be executed,
59 * unless the command starts with a "-".
60 */
61 if (cmd[0] == '-')
62 cmd++;
63 else
64 {
65 clear_bot();
66 putstr("!");
67 putstr(cmd);
68 putstr("\n");
69 }
70
71 #if MSDOS_COMPILER
72 #if MSDOS_COMPILER==WIN32C
73 if (*cmd == '\0')
74 cmd = getenv("COMSPEC");
75 #else
76 /*
77 * Working directory is global on MSDOS.
78 * The child might change the working directory, so we
79 * must save and restore CWD across calls to "system",
80 * or else we won't find our file when we return and
81 * try to "reedit_ifile" it.
82 */
83 getcwd(cwd, FILENAME_MAX);
84 #endif
85 #endif
86
87 /*
88 * Close the current input file.
89 */
90 save_ifile = save_curr_ifile();
91 (void) edit_ifile(NULL_IFILE);
92
93 /*
94 * De-initialize the terminal and take out of raw mode.
95 */
96 term_deinit();
97 flush(); /* Make sure the deinit chars get out */
98 raw_mode(0);
99 #if MSDOS_COMPILER==WIN32C
100 close_getchr();
101 #endif
102
103 /*
104 * Restore signals to their defaults.
105 */
106 init_signals(0);
107
108 #if HAVE_DUP
109 /*
110 * Force standard input to be the user's terminal
111 * (the normal standard input), even if less's standard input
112 * is coming from a pipe.
113 */
114 inp = dup(0);
115 close(0);
116 #if !MSDOS_COMPILER
117 if (open_tty() < 0)
118 #endif
119 dup(inp);
120 #endif
121
122 /*
123 * Pass the command to the system to be executed.
124 * If we have a SHELL environment variable, use
125 * <$SHELL -c "command"> instead of just <command>.
126 * If the command is empty, just invoke a shell.
127 */
128 #if HAVE_SHELL
129 p = NULL;
130 if ((shell = lgetenv("SHELL")) != NULL && *shell != '\0')
131 {
132 if (*cmd == '\0')
133 p = save(shell);
134 else
135 {
136 char *esccmd = shell_quote(cmd);
137 if (esccmd != NULL)
138 {
139 constant char *copt = shell_coption();
140 size_t len = strlen(shell) + strlen(esccmd) + strlen(copt) + 3;
141 p = (char *) ecalloc(len, sizeof(char));
142 SNPRINTF3(p, len, "%s %s %s", shell, copt, esccmd);
143 free(esccmd);
144 }
145 }
146 }
147 if (p == NULL)
148 {
149 if (*cmd == '\0')
150 p = save("sh");
151 else
152 p = save(cmd);
153 }
154 system(p);
155 free(p);
156 #else
157 #if MSDOS_COMPILER==DJGPPC
158 /*
159 * Make stdin of the child be in cooked mode.
160 */
161 setmode(0, O_TEXT);
162 /*
163 * We don't need to catch signals of the child (it
164 * also makes trouble with some DPMI servers).
165 */
166 __djgpp_exception_toggle();
167 system(cmd);
168 __djgpp_exception_toggle();
169 #else
170 system(cmd);
171 #endif
172 #endif
173
174 #if HAVE_DUP
175 /*
176 * Restore standard input, reset signals, raw mode, etc.
177 */
178 close(0);
179 dup(inp);
180 close(inp);
181 #endif
182
183 #if MSDOS_COMPILER==WIN32C
184 open_getchr();
185 #endif
186 init_signals(1);
187 raw_mode(1);
188 if (donemsg != NULL)
189 {
190 putstr(donemsg);
191 putstr(" (press RETURN)");
192 get_return();
193 putchr('\n');
194 flush();
195 }
196 term_init();
197 screen_trashed();
198
199 #if MSDOS_COMPILER && MSDOS_COMPILER!=WIN32C
200 /*
201 * Restore the previous directory (possibly
202 * changed by the child program we just ran).
203 */
204 chdir(cwd);
205 #if MSDOS_COMPILER != DJGPPC
206 /*
207 * Some versions of chdir() don't change to the drive
208 * which is part of CWD. (DJGPP does this in chdir.)
209 */
210 if (cwd[1] == ':')
211 {
212 if (cwd[0] >= 'a' && cwd[0] <= 'z')
213 setdisk(cwd[0] - 'a');
214 else if (cwd[0] >= 'A' && cwd[0] <= 'Z')
215 setdisk(cwd[0] - 'A');
216 }
217 #endif
218 #endif
219
220 /*
221 * Reopen the current input file.
222 */
223 reedit_ifile(save_ifile);
224
225 /*
226 * Since we were ignoring window change signals while we executed
227 * the system command, we must assume the window changed.
228 * Warning: this leaves a signal pending (in "sigs"),
229 * so psignals() should be called soon after lsystem().
230 */
231 sigs |= S_WINCH;
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 term_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 term_init();
355 screen_trashed();
356 #if defined(SIGWINCH) || defined(SIGWIND)
357 /* {{ Probably don't need this here. }} */
358 lwinch(0);
359 #endif
360 return (0);
361 }
362
363 #endif
364