options.c revision cc0e1e4b83d69441cc5f61ea87eda5458ee9fae3 
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
53#ifdef PLT_REINITALISATION_BP
54/* Set a break on the routine named here in order to re-initialize breakpoints
55   after all the PLTs have been initialzed */
56char *PLTs_initialized_by_here = PLT_REINITALISATION_BP;
57#endif
58
59static void
60err_usage(void) {
61	fprintf(stderr, "Try `%s --help' for more information\n", progname);
62	exit(1);
63}
64
65static void
66usage(void) {
67	fprintf(stdout, "Usage: %s [option ...] [command [arg ...]]\n"
68		"Trace library calls of a given program.\n\n"
69		"  -a, --align=COLUMN  align return values in a secific column.\n"
70		"  -A ARRAYLEN         maximum number of array elements to print.\n"
71		"  -b, --no-signals    don't print signals.\n"
72		"  -c                  count time and calls, and report a summary on exit.\n"
73# ifdef USE_DEMANGLE
74		"  -C, --demangle      decode low-level symbol names into user-level names.\n"
75# endif
76		"  -D, --debug=LEVEL   enable debugging (see -Dh or --debug=help).\n"
77		"  -Dh, --debug=help   show help on debugging.\n"
78		"  -e expr             modify which events to trace.\n"
79		"  -f                  trace children (fork() and clone()).\n"
80		"  -F, --config=FILE   load alternate configuration file (may be repeated).\n"
81		"  -g, --no-plt        disable breakpoints on PLT entries.\n"
82		"  -h, --help          display this help and exit.\n"
83		"  -i                  print instruction pointer at time of library call.\n"
84		"  -l, --library=FILE  print library calls from this library only.\n"
85		"  -L                  do NOT display library calls.\n"
86		"  -n, --indent=NR     indent output by NR spaces for each call level nesting.\n"
87		"  -o, --output=FILE   write the trace output to that file.\n"
88		"  -p PID              attach to the process with the process ID pid.\n"
89		"  -r                  print relative timestamps.\n"
90		"  -s STRLEN           specify the maximum string size to print.\n"
91		"  -S                  display system calls.\n"
92		"  -t, -tt, -ttt       print absolute timestamps.\n"
93		"  -T                  show the time spent inside each call.\n"
94		"  -u USERNAME         run command with the userid, groupid of username.\n"
95		"  -V, --version       output version information and exit.\n"
96#if defined(HAVE_LIBUNWIND)
97		"  -w=NR, --where=NR   print backtrace showing NR stack frames at most.\n"
98#endif /* defined(HAVE_LIBUNWIND) */
99		"  -x NAME             treat the global NAME like a library subroutine.\n"
100#ifdef PLT_REINITALISATION_BP
101		"  -X NAME             same as -x; and PLT's will be initialized by here.\n"
102#endif
103		"\nReport bugs to ltrace-devel@lists.alioth.debian.org\n",
104		progname);
105}
106
107static void
108usage_debug(void) {
109	fprintf(stdout, "%s debugging option, --debug=<octal> or -D<octal>:\n", progname);
110	fprintf(stdout,
111			"\n"
112			" number  ref. in source   description\n"
113			"      1   general           Generally helpful progress information\n"
114			"     10   event             Shows every event received by a traced process\n"
115			"     20   process           Shows actions carried upon a traced processes\n"
116			"     40   function          Shows every entry to internal functions\n"
117			"\n"
118			"Debugging options are mixed using bitwise-or.\n"
119			"Note that the meanings and values are subject to change.\n"
120		   );
121}
122
123static char *
124search_for_command(char *filename) {
125	static char pathname[PATH_MAX];
126	char *path;
127	int m, n;
128
129	if (strchr(filename, '/')) {
130		return filename;
131	}
132	for (path = getenv("PATH"); path && *path; path += m) {
133		if (strchr(path, ':')) {
134			n = strchr(path, ':') - path;
135			m = n + 1;
136		} else {
137			m = n = strlen(path);
138		}
139		if (n + strlen(filename) + 1 >= PATH_MAX) {
140			fprintf(stderr, "Error: filename too long\n");
141			exit(1);
142		}
143		strncpy(pathname, path, n);
144		if (n && pathname[n - 1] != '/') {
145			pathname[n++] = '/';
146		}
147		strcpy(pathname + n, filename);
148		if (!access(pathname, X_OK)) {
149			return pathname;
150		}
151	}
152	return filename;
153}
154
155static void
156guess_cols(void) {
157	struct winsize ws;
158	char *c;
159
160	options.align = DEFAULT_ALIGN;
161	c = getenv("COLUMNS");
162	if (c && *c) {
163		char *endptr;
164		int cols;
165		cols = strtol(c, &endptr, 0);
166		if (cols > 0 && !*endptr) {
167			options.align = cols * 5 / 8;
168		}
169	} else if (ioctl(1, TIOCGWINSZ, &ws) != -1 && ws.ws_col > 0) {
170		options.align = ws.ws_col * 5 / 8;
171	} else if (ioctl(2, TIOCGWINSZ, &ws) != -1 && ws.ws_col > 0) {
172		options.align = ws.ws_col * 5 / 8;
173	}
174}
175
176static void
177add_filter_rule(struct filter *filt, const char *expr,
178		enum filter_rule_type type,
179		const char *a_sym, int sym_re_p,
180		const char *a_lib, int lib_re_p)
181{
182	struct filter_rule *rule = malloc(sizeof(*rule));
183	struct filter_lib_matcher *matcher = malloc(sizeof(*matcher));
184
185	if (rule == NULL || matcher == NULL) {
186		fprintf(stderr, "rule near '%s' will be ignored: %s\n",
187			expr, strerror(errno));
188	fail:
189		free(rule);
190		free(matcher);
191		return;
192	}
193
194	regex_t symbol_re;
195	int status;
196	{
197		/* Add ^ to the start of expression and $ to the end, so that
198		 * we match the whole symbol name.  Let the user write the "*"
199		 * explicitly if they wish.  */
200		char sym[strlen(a_sym) + 3];
201		sprintf(sym, "^%s$", a_sym);
202		status = (sym_re_p ? regcomp : globcomp)(&symbol_re, sym, 0);
203		if (status != 0) {
204			char buf[100];
205			regerror(status, &symbol_re, buf, sizeof buf);
206			fprintf(stderr, "rule near '%s' will be ignored: %s\n",
207				expr, buf);
208			goto fail;
209		}
210	}
211
212	if (strcmp(a_lib, "MAIN") == 0) {
213		filter_lib_matcher_main_init(matcher);
214	} else {
215		/* Add ^ and $ to the library expression as well.  */
216		char lib[strlen(a_lib) + 3];
217		sprintf(lib, "^%s$", a_lib);
218
219		enum filter_lib_matcher_type type
220			= lib[0] == '/' ? FLM_PATHNAME : FLM_SONAME;
221
222		regex_t lib_re;
223		status = (lib_re_p ? regcomp : globcomp)(&lib_re, lib, 0);
224		if (status != 0) {
225			char buf[100];
226			regerror(status, &lib_re, buf, sizeof buf);
227			fprintf(stderr, "rule near '%s' will be ignored: %s\n",
228				expr, buf);
229
230			regfree(&symbol_re);
231			goto fail;
232		}
233		filter_lib_matcher_name_init(matcher, type, lib_re);
234	}
235
236	filter_rule_init(rule, type, matcher, symbol_re);
237	filter_add_rule(filt, rule);
238}
239
240static int
241parse_filter(struct filter *filt, char *expr)
242{
243	/* Filter is a chain of sym@lib rules separated by '-'.  If
244	 * the filter expression starts with '-', the missing initial
245	 * rule is implicitly *@*.  */
246
247	enum filter_rule_type type = FR_ADD;
248
249	while (*expr != 0) {
250		size_t s = strcspn(expr, "@-+");
251		char *symname = expr;
252		char *libname;
253		char *next = expr + s + 1;
254		enum filter_rule_type this_type = type;
255
256		if (expr[s] == 0) {
257			libname = "*";
258			expr = next - 1;
259
260		} else if (expr[s] == '-' || expr[s] == '+') {
261			type = expr[s] == '-' ? FR_SUBTRACT : FR_ADD;
262			expr[s] = 0;
263			libname = "*";
264			expr = next;
265
266		} else {
267			assert(expr[s] == '@');
268			expr[s] = 0;
269			s = strcspn(next, "-+");
270			if (s == 0) {
271				libname = "*";
272				expr = next;
273			} else if (next[s] == 0) {
274				expr = next + s;
275				libname = next;
276			} else {
277				assert(next[s] == '-' || next[s] == '+');
278				type = next[s] == '-' ? FR_SUBTRACT : FR_ADD;
279				next[s] = 0;
280				expr = next + s + 1;
281				libname = next;
282			}
283		}
284
285		assert(*libname != 0);
286		char *symend = symname + strlen(symname) - 1;
287		char *libend = libname + strlen(libname) - 1;
288		int sym_is_re = 0;
289		int lib_is_re = 0;
290
291		/*
292		 * /xxx/@... and ...@/xxx/ means that xxx are regular
293		 * expressions.  They are globs otherwise.
294		 *
295		 * /xxx@yyy/ is the same as /xxx/@/yyy/
296		 *
297		 * @/xxx matches library path name
298		 * @.xxx matches library relative path name
299		 */
300		if (symname[0] == '/') {
301			if (symname != symend && symend[0] == '/') {
302				++symname;
303				*symend-- = 0;
304				sym_is_re = 1;
305
306			} else {
307				sym_is_re = 1;
308				lib_is_re = 1;
309				++symname;
310
311				/* /XXX@YYY/ is the same as
312				 * /XXX/@/YYY/.  */
313				if (libend[0] != '/')
314					fprintf(stderr, "unmatched '/'"
315						" in symbol name\n");
316				else
317					*libend-- = 0;
318			}
319		}
320
321		/* If libname ends in '/', then we expect '/' in the
322		 * beginning too.  Otherwise the initial '/' is part
323		 * of absolute file name.  */
324		if (!lib_is_re && libend[0] == '/') {
325			lib_is_re = 1;
326			*libend-- = 0;
327			if (libname != libend && libname[0] == '/')
328				++libname;
329			else
330				fprintf(stderr, "unmatched '/'"
331					" in library name\n");
332		}
333
334		if (*symname == 0) /* /@AA/ */
335			symname = "*";
336		if (*libname == 0) /* /aa@/ */
337			libname = "*";
338
339		add_filter_rule(filt, expr, this_type,
340				symname, sym_is_re,
341				libname, lib_is_re);
342	}
343
344	return 0;
345}
346
347static struct filter *
348recursive_parse_chain(char *expr)
349{
350	struct filter *filt = malloc(sizeof(*filt));
351	if (filt == NULL) {
352		fprintf(stderr, "(part of) filter will be ignored: '%s': %s\n",
353			expr, strerror(errno));
354		return NULL;
355	}
356
357	filter_init(filt);
358	if (parse_filter(filt, expr) < 0) {
359		fprintf(stderr, "Filter '%s' will be ignored.\n", expr);
360		free(filt);
361		filt = NULL;
362	}
363
364	return filt;
365}
366
367static void
368parse_filter_chain(const char *expr, struct filter **retp)
369{
370	char *str = strdup(expr);
371	if (str == NULL) {
372		fprintf(stderr, "filter '%s' will be ignored: %s\n",
373			expr, strerror(errno));
374		return;
375	}
376	/* Support initial '!' for backward compatibility.  */
377	if (str[0] == '!')
378		str[0] = '-';
379
380	struct filter **tailp;
381	for (tailp = retp; *tailp != NULL; tailp = &(*tailp)->next)
382		;
383	*tailp = recursive_parse_chain(str);
384}
385
386char **
387process_options(int argc, char **argv)
388{
389	progname = argv[0];
390	options.output = stderr;
391	options.no_signals = 0;
392#if defined(HAVE_LIBUNWIND)
393	options.bt_depth = -1;
394#endif /* defined(HAVE_LIBUNWIND) */
395
396	guess_cols();
397
398	int libcalls = 1;
399
400	while (1) {
401		int c;
402		char *p;
403		int option_index = 0;
404		static struct option long_options[] = {
405			{"align", 1, 0, 'a'},
406			{"config", 1, 0, 'F'},
407			{"debug", 1, 0, 'D'},
408# ifdef USE_DEMANGLE
409			{"demangle", 0, 0, 'C'},
410#endif
411			{"indent", 1, 0, 'n'},
412			{"help", 0, 0, 'h'},
413			{"library", 1, 0, 'l'},
414			{"output", 1, 0, 'o'},
415			{"version", 0, 0, 'V'},
416			{"no-signals", 0, 0, 'b'},
417#if defined(HAVE_LIBUNWIND)
418			{"where", 1, 0, 'w'},
419#endif /* defined(HAVE_LIBUNWIND) */
420			{0, 0, 0, 0}
421		};
422		c = getopt_long(argc, argv, "+cfhiLrStTVb"
423# ifdef USE_DEMANGLE
424				"C"
425# endif
426#if defined(HAVE_LIBUNWIND)
427				"a:A:D:e:F:l:n:o:p:s:u:x:X:w:", long_options,
428#else /* !defined(HAVE_LIBUNWIND) */
429				"a:A:D:e:F:l:n:o:p:s:u:x:X:", long_options,
430#endif
431				&option_index);
432		if (c == -1) {
433			break;
434		}
435		switch (c) {
436		case 'a':
437			options.align = atoi(optarg);
438			break;
439		case 'A':
440			options.arraylen = atoi(optarg);
441			break;
442		case 'b':
443			options.no_signals = 1;
444			break;
445		case 'c':
446			options.summary++;
447			break;
448#ifdef USE_DEMANGLE
449		case 'C':
450			options.demangle++;
451			break;
452#endif
453		case 'D':
454			if (optarg[0]=='h') {
455				usage_debug();
456				exit(0);
457			}
458			options.debug = strtoul(optarg,&p,8);
459			if (*p) {
460				fprintf(stderr, "%s: --debug requires an octal argument\n", progname);
461				err_usage();
462			}
463			break;
464
465		case 'e':
466			parse_filter_chain(optarg, &options.plt_filter);
467			break;
468
469		case 'f':
470			options.follow = 1;
471			break;
472		case 'F':
473			{
474				struct opt_F_t *tmp = malloc(sizeof(struct opt_F_t));
475				if (!tmp) {
476					perror("ltrace: malloc");
477					exit(1);
478				}
479				tmp->filename = strdup(optarg);
480				tmp->next = opt_F;
481				opt_F = tmp;
482				break;
483			}
484		case 'h':
485			usage();
486			exit(0);
487		case 'i':
488			opt_i++;
489			break;
490		case 'l':
491			// XXX TODO
492			fprintf(stderr, "-l support not yet implemented\n");
493			break;
494		case 'L':
495			libcalls = 0;
496			break;
497		case 'n':
498			options.indent = atoi(optarg);
499			break;
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		case 'X':
554#ifdef PLT_REINITALISATION_BP
555			PLTs_initialized_by_here = optarg;
556#else
557			fprintf(stderr, "WARNING: \"-X\" not used for this "
558				"architecture: assuming you meant \"-x\"\n");
559#endif
560			/* Fall Thru */
561
562		case 'x':
563			parse_filter_chain(optarg, &options.static_filter);
564			break;
565
566		default:
567			err_usage();
568		}
569	}
570	argc -= optind;
571	argv += optind;
572
573	if (!opt_F) {
574		opt_F = malloc(sizeof(struct opt_F_t));
575		opt_F->next = malloc(sizeof(struct opt_F_t));
576		opt_F->next->next = NULL;
577		opt_F->filename = USER_CONFIG_FILE;
578		opt_F->next->filename = SYSTEM_CONFIG_FILE;
579	}
580	/* Reverse the config file list since it was built by
581	 * prepending, and it would make more sense to process the
582	 * files in the order they were given. Probably it would make
583	 * more sense to keep a tail pointer instead? */
584	{
585		struct opt_F_t *egg = NULL;
586		struct opt_F_t *chicken;
587		while (opt_F) {
588			chicken = opt_F->next;
589			opt_F->next = egg;
590			egg = opt_F;
591			opt_F = chicken;
592		}
593		opt_F = egg;
594	}
595
596	/* Set default filter.  Use @MAIN for now, as that's what
597	 * ltrace used to have in the past.  XXX Maybe we should make
598	 * this "*" instead.  */
599	if (options.plt_filter == NULL && libcalls) {
600		parse_filter_chain("@MAIN", &options.plt_filter);
601		options.hide_caller = 1;
602	}
603
604	if (!opt_p && argc < 1) {
605		fprintf(stderr, "%s: too few arguments\n", progname);
606		err_usage();
607	}
608	if (opt_r && opt_t) {
609		fprintf(stderr, "%s: Incompatible options -r and -t\n",
610			progname);
611		err_usage();
612	}
613	if (argc > 0) {
614		command = search_for_command(argv[0]);
615	}
616	return &argv[0];
617}
618