options.c revision d57c9f8a8515781d687ce57eadc371038cd01526 
1#include "config.h"
2
3#include <sys/ioctl.h>
4#include <assert.h>
5#include <errno.h>
6#include <fcntl.h>
7#include <getopt.h>
8#include <limits.h>
9#include <stdio.h>
10#include <stdlib.h>
11#include <string.h>
12#include <unistd.h>
13
14#include "common.h"
15#include "filter.h"
16#include "glob.h"
17
18#ifndef SYSCONFDIR
19#define SYSCONFDIR "/etc"
20#endif
21
22#define SYSTEM_CONFIG_FILE SYSCONFDIR "/ltrace.conf"
23#define USER_CONFIG_FILE "~/.ltrace.conf"
24
25struct options_t options = {
26	.align    = DEFAULT_ALIGN,    /* alignment column for results */
27	.user     = NULL,             /* username to run command as */
28	.syscalls = 0,                /* display syscalls */
29#ifdef USE_DEMANGLE
30	.demangle = 0,                /* Demangle low-level symbol names */
31#endif
32	.indent = 0,                  /* indent output according to program flow */
33	.output = NULL,               /* output to a specific file */
34	.summary = 0,                 /* Report a summary on program exit */
35	.debug = 0,                   /* debug */
36	.arraylen = DEFAULT_ARRAYLEN, /* maximum # array elements to print */
37	.strlen = DEFAULT_STRLEN,     /* maximum # of bytes printed in strings */
38	.follow = 0,                  /* trace child processes */
39};
40
41static char *progname;		/* Program name (`ltrace') */
42int opt_i = 0;			/* instruction pointer */
43int opt_r = 0;			/* print relative timestamp */
44int opt_t = 0;			/* print absolute timestamp */
45int opt_T = 0;			/* show the time spent inside each call */
46
47/* List of pids given to option -p: */
48struct opt_p_t *opt_p = NULL;	/* attach to process with a given pid */
49
50/* List of filenames give to option -F: */
51struct opt_F_t *opt_F = NULL;	/* alternate configuration file(s) */
52
53static void
54err_usage(void) {
55	fprintf(stderr, "Try `%s --help' for more information\n", progname);
56	exit(1);
57}
58
59static void
60usage(void) {
61	fprintf(stdout, "Usage: %s [option ...] [command [arg ...]]\n"
62		"Trace library calls of a given program.\n\n"
63		"  -a, --align=COLUMN  align return values in a secific column.\n"
64		"  -A ARRAYLEN         maximum number of array elements to print.\n"
65		"  -b, --no-signals    don't print signals.\n"
66		"  -c                  count time and calls, and report a summary on exit.\n"
67# ifdef USE_DEMANGLE
68		"  -C, --demangle      decode low-level symbol names into user-level names.\n"
69# endif
70		"  -D, --debug=LEVEL   enable debugging (see -Dh or --debug=help).\n"
71		"  -Dh, --debug=help   show help on debugging.\n"
72		"  -e expr             modify which events to trace.\n"
73		"  -f                  trace children (fork() and clone()).\n"
74		"  -F, --config=FILE   load alternate configuration file (may be repeated).\n"
75		"  -h, --help          display this help and exit.\n"
76		"  -i                  print instruction pointer at time of library call.\n"
77		"  -l, --library=FILE  print library calls from this library only.\n"
78		"  -L                  do NOT display library calls.\n"
79		"  -n, --indent=NR     indent output by NR spaces for each call level nesting.\n"
80		"  -o, --output=FILE   write the trace output to that file.\n"
81		"  -p PID              attach to the process with the process ID pid.\n"
82		"  -r                  print relative timestamps.\n"
83		"  -s STRLEN           specify the maximum string size to print.\n"
84		"  -S                  display system calls.\n"
85		"  -t, -tt, -ttt       print absolute timestamps.\n"
86		"  -T                  show the time spent inside each call.\n"
87		"  -u USERNAME         run command with the userid, groupid of username.\n"
88		"  -V, --version       output version information and exit.\n"
89#if defined(HAVE_LIBUNWIND)
90		"  -w=NR, --where=NR   print backtrace showing NR stack frames at most.\n"
91#endif /* defined(HAVE_LIBUNWIND) */
92		"  -x NAME             treat the global NAME like a library subroutine.\n"
93		"\nReport bugs to ltrace-devel@lists.alioth.debian.org\n",
94		progname);
95}
96
97static void
98usage_debug(void) {
99	fprintf(stdout, "%s debugging option, --debug=<octal> or -D<octal>:\n", progname);
100	fprintf(stdout,
101			"\n"
102			" number  ref. in source   description\n"
103			"      1   general           Generally helpful progress information\n"
104			"     10   event             Shows every event received by a traced process\n"
105			"     20   process           Shows actions carried upon a traced processes\n"
106			"     40   function          Shows every entry to internal functions\n"
107			"\n"
108			"Debugging options are mixed using bitwise-or.\n"
109			"Note that the meanings and values are subject to change.\n"
110		   );
111}
112
113static char *
114search_for_command(char *filename) {
115	static char pathname[PATH_MAX];
116	char *path;
117	int m, n;
118
119	if (strchr(filename, '/')) {
120		return filename;
121	}
122	for (path = getenv("PATH"); path && *path; path += m) {
123		if (strchr(path, ':')) {
124			n = strchr(path, ':') - path;
125			m = n + 1;
126		} else {
127			m = n = strlen(path);
128		}
129		if (n + strlen(filename) + 1 >= PATH_MAX) {
130			fprintf(stderr, "Error: filename too long\n");
131			exit(1);
132		}
133		strncpy(pathname, path, n);
134		if (n && pathname[n - 1] != '/') {
135			pathname[n++] = '/';
136		}
137		strcpy(pathname + n, filename);
138		if (!access(pathname, X_OK)) {
139			return pathname;
140		}
141	}
142	return filename;
143}
144
145static void
146guess_cols(void) {
147	struct winsize ws;
148	char *c;
149
150	options.align = DEFAULT_ALIGN;
151	c = getenv("COLUMNS");
152	if (c && *c) {
153		char *endptr;
154		int cols;
155		cols = strtol(c, &endptr, 0);
156		if (cols > 0 && !*endptr) {
157			options.align = cols * 5 / 8;
158		}
159	} else if (ioctl(1, TIOCGWINSZ, &ws) != -1 && ws.ws_col > 0) {
160		options.align = ws.ws_col * 5 / 8;
161	} else if (ioctl(2, TIOCGWINSZ, &ws) != -1 && ws.ws_col > 0) {
162		options.align = ws.ws_col * 5 / 8;
163	}
164}
165
166static void
167add_filter_rule(struct filter *filt, const char *expr,
168		enum filter_rule_type type,
169		const char *a_sym, int sym_re_p,
170		const char *a_lib, int lib_re_p)
171{
172	struct filter_rule *rule = malloc(sizeof(*rule));
173	struct filter_lib_matcher *matcher = malloc(sizeof(*matcher));
174
175	if (rule == NULL || matcher == NULL) {
176		fprintf(stderr, "rule near '%s' will be ignored: %s\n",
177			expr, strerror(errno));
178	fail:
179		free(rule);
180		free(matcher);
181		return;
182	}
183
184	regex_t symbol_re;
185	int status;
186	{
187		/* Add ^ to the start of expression and $ to the end, so that
188		 * we match the whole symbol name.  Let the user write the "*"
189		 * explicitly if they wish.  */
190		char sym[strlen(a_sym) + 3];
191		sprintf(sym, "^%s$", a_sym);
192		status = (sym_re_p ? regcomp : globcomp)(&symbol_re, sym, 0);
193		if (status != 0) {
194			char buf[100];
195			regerror(status, &symbol_re, buf, sizeof buf);
196			fprintf(stderr, "rule near '%s' will be ignored: %s\n",
197				expr, buf);
198			goto fail;
199		}
200	}
201
202	if (strcmp(a_lib, "MAIN") == 0) {
203		filter_lib_matcher_main_init(matcher);
204	} else {
205		/* Add ^ and $ to the library expression as well.  */
206		char lib[strlen(a_lib) + 3];
207		sprintf(lib, "^%s$", a_lib);
208
209		enum filter_lib_matcher_type type
210			= lib[0] == '/' ? FLM_PATHNAME : FLM_SONAME;
211
212		regex_t lib_re;
213		status = (lib_re_p ? regcomp : globcomp)(&lib_re, lib, 0);
214		if (status != 0) {
215			char buf[100];
216			regerror(status, &lib_re, buf, sizeof buf);
217			fprintf(stderr, "rule near '%s' will be ignored: %s\n",
218				expr, buf);
219
220			regfree(&symbol_re);
221			goto fail;
222		}
223		filter_lib_matcher_name_init(matcher, type, lib_re);
224	}
225
226	filter_rule_init(rule, type, matcher, symbol_re);
227	filter_add_rule(filt, rule);
228}
229
230static int
231parse_filter(struct filter *filt, char *expr)
232{
233	/* Filter is a chain of sym@lib rules separated by '-'.  If
234	 * the filter expression starts with '-', the missing initial
235	 * rule is implicitly *@*.  */
236
237	enum filter_rule_type type = FR_ADD;
238
239	while (*expr != 0) {
240		size_t s = strcspn(expr, "@-+");
241		char *symname = expr;
242		char *libname;
243		char *next = expr + s + 1;
244		enum filter_rule_type this_type = type;
245
246		if (expr[s] == 0) {
247			libname = "*";
248			expr = next - 1;
249
250		} else if (expr[s] == '-' || expr[s] == '+') {
251			type = expr[s] == '-' ? FR_SUBTRACT : FR_ADD;
252			expr[s] = 0;
253			libname = "*";
254			expr = next;
255
256		} else {
257			assert(expr[s] == '@');
258			expr[s] = 0;
259			s = strcspn(next, "-+");
260			if (s == 0) {
261				libname = "*";
262				expr = next;
263			} else if (next[s] == 0) {
264				expr = next + s;
265				libname = next;
266			} else {
267				assert(next[s] == '-' || next[s] == '+');
268				type = next[s] == '-' ? FR_SUBTRACT : FR_ADD;
269				next[s] = 0;
270				expr = next + s + 1;
271				libname = next;
272			}
273		}
274
275		assert(*libname != 0);
276		char *symend = symname + strlen(symname) - 1;
277		char *libend = libname + strlen(libname) - 1;
278		int sym_is_re = 0;
279		int lib_is_re = 0;
280
281		/*
282		 * /xxx/@... and ...@/xxx/ means that xxx are regular
283		 * expressions.  They are globs otherwise.
284		 *
285		 * /xxx@yyy/ is the same as /xxx/@/yyy/
286		 *
287		 * @/xxx matches library path name
288		 * @.xxx matches library relative path name
289		 */
290		if (symname[0] == '/') {
291			if (symname != symend && symend[0] == '/') {
292				++symname;
293				*symend-- = 0;
294				sym_is_re = 1;
295
296			} else {
297				sym_is_re = 1;
298				lib_is_re = 1;
299				++symname;
300
301				/* /XXX@YYY/ is the same as
302				 * /XXX/@/YYY/.  */
303				if (libend[0] != '/')
304					fprintf(stderr, "unmatched '/'"
305						" in symbol name\n");
306				else
307					*libend-- = 0;
308			}
309		}
310
311		/* If libname ends in '/', then we expect '/' in the
312		 * beginning too.  Otherwise the initial '/' is part
313		 * of absolute file name.  */
314		if (!lib_is_re && libend[0] == '/') {
315			lib_is_re = 1;
316			*libend-- = 0;
317			if (libname != libend && libname[0] == '/')
318				++libname;
319			else
320				fprintf(stderr, "unmatched '/'"
321					" in library name\n");
322		}
323
324		if (*symname == 0) /* /@AA/ */
325			symname = "*";
326		if (*libname == 0) /* /aa@/ */
327			libname = "*";
328
329		add_filter_rule(filt, expr, this_type,
330				symname, sym_is_re,
331				libname, lib_is_re);
332	}
333
334	return 0;
335}
336
337static struct filter *
338recursive_parse_chain(char *expr)
339{
340	struct filter *filt = malloc(sizeof(*filt));
341	if (filt == NULL) {
342		fprintf(stderr, "(part of) filter will be ignored: '%s': %s\n",
343			expr, strerror(errno));
344		return NULL;
345	}
346
347	filter_init(filt);
348	if (parse_filter(filt, expr) < 0) {
349		fprintf(stderr, "Filter '%s' will be ignored.\n", expr);
350		free(filt);
351		filt = NULL;
352	}
353
354	return filt;
355}
356
357static void
358parse_filter_chain(const char *expr, struct filter **retp)
359{
360	char *str = strdup(expr);
361	if (str == NULL) {
362		fprintf(stderr, "filter '%s' will be ignored: %s\n",
363			expr, strerror(errno));
364		return;
365	}
366	/* Support initial '!' for backward compatibility.  */
367	if (str[0] == '!')
368		str[0] = '-';
369
370	struct filter **tailp;
371	for (tailp = retp; *tailp != NULL; tailp = &(*tailp)->next)
372		;
373	*tailp = recursive_parse_chain(str);
374}
375
376char **
377process_options(int argc, char **argv)
378{
379	progname = argv[0];
380	options.output = stderr;
381	options.no_signals = 0;
382#if defined(HAVE_LIBUNWIND)
383	options.bt_depth = -1;
384#endif /* defined(HAVE_LIBUNWIND) */
385
386	guess_cols();
387
388	int libcalls = 1;
389
390	while (1) {
391		int c;
392		char *p;
393		int option_index = 0;
394		static struct option long_options[] = {
395			{"align", 1, 0, 'a'},
396			{"config", 1, 0, 'F'},
397			{"debug", 1, 0, 'D'},
398# ifdef USE_DEMANGLE
399			{"demangle", 0, 0, 'C'},
400#endif
401			{"indent", 1, 0, 'n'},
402			{"help", 0, 0, 'h'},
403			{"library", 1, 0, 'l'},
404			{"output", 1, 0, 'o'},
405			{"version", 0, 0, 'V'},
406			{"no-signals", 0, 0, 'b'},
407#if defined(HAVE_LIBUNWIND)
408			{"where", 1, 0, 'w'},
409#endif /* defined(HAVE_LIBUNWIND) */
410			{0, 0, 0, 0}
411		};
412		c = getopt_long(argc, argv, "+cfhiLrStTVb"
413# ifdef USE_DEMANGLE
414				"C"
415# endif
416#if defined(HAVE_LIBUNWIND)
417				"a:A:D:e:F:l:n:o:p:s:u:x:X:w:", long_options,
418#else /* !defined(HAVE_LIBUNWIND) */
419				"a:A:D:e:F:l:n:o:p:s:u:x:X:", long_options,
420#endif
421				&option_index);
422		if (c == -1) {
423			break;
424		}
425		switch (c) {
426		case 'a':
427			options.align = atoi(optarg);
428			break;
429		case 'A':
430			options.arraylen = atoi(optarg);
431			break;
432		case 'b':
433			options.no_signals = 1;
434			break;
435		case 'c':
436			options.summary++;
437			break;
438#ifdef USE_DEMANGLE
439		case 'C':
440			options.demangle++;
441			break;
442#endif
443		case 'D':
444			if (optarg[0]=='h') {
445				usage_debug();
446				exit(0);
447			}
448			options.debug = strtoul(optarg,&p,8);
449			if (*p) {
450				fprintf(stderr, "%s: --debug requires an octal argument\n", progname);
451				err_usage();
452			}
453			break;
454
455		case 'e':
456			parse_filter_chain(optarg, &options.plt_filter);
457			break;
458
459		case 'f':
460			options.follow = 1;
461			break;
462		case 'F':
463			{
464				struct opt_F_t *tmp = malloc(sizeof(struct opt_F_t));
465				if (!tmp) {
466					perror("ltrace: malloc");
467					exit(1);
468				}
469				tmp->filename = strdup(optarg);
470				tmp->next = opt_F;
471				opt_F = tmp;
472				break;
473			}
474		case 'h':
475			usage();
476			exit(0);
477		case 'i':
478			opt_i++;
479			break;
480		case 'l':
481			// XXX TODO
482			fprintf(stderr, "-l support not yet implemented\n");
483			break;
484		case 'L':
485			libcalls = 0;
486			break;
487		case 'n': {
488			char *endptr;
489			long int l = strtol(optarg, &endptr, 0);
490			/* Arbitrary cut-off.  Nobody needs to indent
491			 * more than, say, 8, anyway.  */
492			if (l < 0 || l > 20 || *optarg == 0 || *endptr != 0) {
493				fprintf(stderr, "Invalid argument to -n: '%s'."
494					"  Use integer 0..20.\n", optarg);
495				exit(1);
496			}
497			options.indent = (int)l;
498			break;
499		}
500		case 'o':
501			options.output = fopen(optarg, "w");
502			if (!options.output) {
503				fprintf(stderr,
504					"can't open %s for writing: %s\n",
505					optarg, strerror(errno));
506				exit(1);
507			}
508			setvbuf(options.output, (char *)NULL, _IOLBF, 0);
509			fcntl(fileno(options.output), F_SETFD, FD_CLOEXEC);
510			break;
511		case 'p':
512			{
513				struct opt_p_t *tmp = malloc(sizeof(struct opt_p_t));
514				if (!tmp) {
515					perror("ltrace: malloc");
516					exit(1);
517				}
518				tmp->pid = atoi(optarg);
519				tmp->next = opt_p;
520				opt_p = tmp;
521				break;
522			}
523		case 'r':
524			opt_r++;
525			break;
526		case 's':
527			options.strlen = atoi(optarg);
528			break;
529		case 'S':
530			options.syscalls = 1;
531			break;
532		case 't':
533			opt_t++;
534			break;
535		case 'T':
536			opt_T++;
537			break;
538		case 'u':
539			options.user = optarg;
540			break;
541		case 'V':
542			printf("ltrace version " PACKAGE_VERSION ".\n"
543					"Copyright (C) 1997-2009 Juan Cespedes <cespedes@debian.org>.\n"
544					"This is free software; see the GNU General Public Licence\n"
545					"version 2 or later for copying conditions.  There is NO warranty.\n");
546			exit(0);
547			break;
548#if defined(HAVE_LIBUNWIND)
549		case 'w':
550			options.bt_depth = atoi(optarg);
551			break;
552#endif /* defined(HAVE_LIBUNWIND) */
553
554		case 'x':
555			parse_filter_chain(optarg, &options.static_filter);
556			break;
557
558		default:
559			err_usage();
560		}
561	}
562	argc -= optind;
563	argv += optind;
564
565	if (!opt_F) {
566		opt_F = malloc(sizeof(struct opt_F_t));
567		opt_F->next = malloc(sizeof(struct opt_F_t));
568		opt_F->next->next = NULL;
569		opt_F->filename = USER_CONFIG_FILE;
570		opt_F->next->filename = SYSTEM_CONFIG_FILE;
571	}
572	/* Reverse the config file list since it was built by
573	 * prepending, and it would make more sense to process the
574	 * files in the order they were given. Probably it would make
575	 * more sense to keep a tail pointer instead? */
576	{
577		struct opt_F_t *egg = NULL;
578		struct opt_F_t *chicken;
579		while (opt_F) {
580			chicken = opt_F->next;
581			opt_F->next = egg;
582			egg = opt_F;
583			opt_F = chicken;
584		}
585		opt_F = egg;
586	}
587
588	/* Set default filter.  Use @MAIN for now, as that's what
589	 * ltrace used to have in the past.  XXX Maybe we should make
590	 * this "*" instead.  */
591	if (options.plt_filter == NULL && libcalls) {
592		parse_filter_chain("@MAIN", &options.plt_filter);
593		options.hide_caller = 1;
594	}
595
596	if (!opt_p && argc < 1) {
597		fprintf(stderr, "%s: too few arguments\n", progname);
598		err_usage();
599	}
600	if (opt_r && opt_t) {
601		fprintf(stderr, "%s: Incompatible options -r and -t\n",
602			progname);
603		err_usage();
604	}
605	if (argc > 0) {
606		command = search_for_command(argv[0]);
607	}
608	return &argv[0];
609}
610