1/*
2 * Copyright (C) 1984-2023  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
35extern int screen_trashed;
36extern 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 */
45public void lsystem(char *cmd, char *donemsg)
46{
47	int inp;
48#if HAVE_SHELL
49	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	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				int len = (int) (strlen(shell) + strlen(esccmd) + 5);
140				p = (char *) ecalloc(len, sizeof(char));
141				SNPRINTF3(p, len, "%s %s %s", shell, shell_coption(), esccmd);
142				free(esccmd);
143			}
144		}
145	}
146	if (p == NULL)
147	{
148		if (*cmd == '\0')
149			p = save("sh");
150		else
151			p = save(cmd);
152	}
153	system(p);
154	free(p);
155#else
156#if MSDOS_COMPILER==DJGPPC
157	/*
158	 * Make stdin of the child be in cooked mode.
159	 */
160	setmode(0, O_TEXT);
161	/*
162	 * We don't need to catch signals of the child (it
163	 * also makes trouble with some DPMI servers).
164	 */
165	__djgpp_exception_toggle();
166	system(cmd);
167	__djgpp_exception_toggle();
168#else
169	system(cmd);
170#endif
171#endif
172
173#if HAVE_DUP
174	/*
175	 * Restore standard input, reset signals, raw mode, etc.
176	 */
177	close(0);
178	dup(inp);
179	close(inp);
180#endif
181
182#if MSDOS_COMPILER==WIN32C
183	open_getchr();
184#endif
185	init_signals(1);
186	raw_mode(1);
187	if (donemsg != NULL)
188	{
189		putstr(donemsg);
190		putstr("  (press RETURN)");
191		get_return();
192		putchr('\n');
193		flush();
194	}
195	init();
196	screen_trashed = 1;
197
198#if MSDOS_COMPILER && MSDOS_COMPILER!=WIN32C
199	/*
200	 * Restore the previous directory (possibly
201	 * changed by the child program we just ran).
202	 */
203	chdir(cwd);
204#if MSDOS_COMPILER != DJGPPC
205	/*
206	 * Some versions of chdir() don't change to the drive
207	 * which is part of CWD.  (DJGPP does this in chdir.)
208	 */
209	if (cwd[1] == ':')
210	{
211		if (cwd[0] >= 'a' && cwd[0] <= 'z')
212			setdisk(cwd[0] - 'a');
213		else if (cwd[0] >= 'A' && cwd[0] <= 'Z')
214			setdisk(cwd[0] - 'A');
215	}
216#endif
217#endif
218
219	/*
220	 * Reopen the current input file.
221	 */
222	reedit_ifile(save_ifile);
223
224#if defined(SIGWINCH) || defined(SIGWIND)
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	winch(0);
232#endif
233}
234
235#endif
236
237#if PIPEC
238
239/*
240 * Pipe a section of the input file into the given shell command.
241 * The section to be piped is the section "between" the current
242 * position and the position marked by the given letter.
243 *
244 * If the mark is after the current screen, the section between
245 * the top line displayed and the mark is piped.
246 * If the mark is before the current screen, the section between
247 * the mark and the bottom line displayed is piped.
248 * If the mark is on the current screen, or if the mark is ".",
249 * the whole current screen is piped.
250 */
251public int pipe_mark(int c, char *cmd)
252{
253	POSITION mpos, tpos, bpos;
254
255	/*
256	 * mpos = the marked position.
257	 * tpos = top of screen.
258	 * bpos = bottom of screen.
259	 */
260	mpos = markpos(c);
261	if (mpos == NULL_POSITION)
262		return (-1);
263	tpos = position(TOP);
264	if (tpos == NULL_POSITION)
265		tpos = ch_zero();
266	bpos = position(BOTTOM);
267
268	if (c == '.')
269		return (pipe_data(cmd, tpos, bpos));
270	else if (mpos <= tpos)
271		return (pipe_data(cmd, mpos, bpos));
272	else if (bpos == NULL_POSITION)
273		return (pipe_data(cmd, tpos, bpos));
274	else
275		return (pipe_data(cmd, tpos, mpos));
276}
277
278/*
279 * Create a pipe to the given shell command.
280 * Feed it the file contents between the positions spos and epos.
281 */
282public int pipe_data(char *cmd, POSITION spos, POSITION epos)
283{
284	FILE *f;
285	int c;
286
287	/*
288	 * This is structured much like lsystem().
289	 * Since we're running a shell program, we must be careful
290	 * to perform the necessary deinitialization before running
291	 * the command, and reinitialization after it.
292	 */
293	if (ch_seek(spos) != 0)
294	{
295		error("Cannot seek to start position", NULL_PARG);
296		return (-1);
297	}
298
299	if ((f = popen(cmd, "w")) == NULL)
300	{
301		error("Cannot create pipe", NULL_PARG);
302		return (-1);
303	}
304	clear_bot();
305	putstr("!");
306	putstr(cmd);
307	putstr("\n");
308
309	deinit();
310	flush();
311	raw_mode(0);
312	init_signals(0);
313#if MSDOS_COMPILER==WIN32C
314	close_getchr();
315#endif
316#ifdef SIGPIPE
317	LSIGNAL(SIGPIPE, SIG_IGN);
318#endif
319
320	c = EOI;
321	while (epos == NULL_POSITION || spos++ <= epos)
322	{
323		/*
324		 * Read a character from the file and give it to the pipe.
325		 */
326		c = ch_forw_get();
327		if (c == EOI)
328			break;
329		if (putc(c, f) == EOF)
330			break;
331	}
332
333	/*
334	 * Finish up the last line.
335	 */
336	while (c != '\n' && c != EOI )
337	{
338		c = ch_forw_get();
339		if (c == EOI)
340			break;
341		if (putc(c, f) == EOF)
342			break;
343	}
344
345	pclose(f);
346
347#ifdef SIGPIPE
348	LSIGNAL(SIGPIPE, SIG_DFL);
349#endif
350#if MSDOS_COMPILER==WIN32C
351	open_getchr();
352#endif
353	init_signals(1);
354	raw_mode(1);
355	init();
356	screen_trashed = 1;
357#if defined(SIGWINCH) || defined(SIGWIND)
358	/* {{ Probably don't need this here. }} */
359	winch(0);
360#endif
361	return (0);
362}
363
364#endif
365