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a9171047 | 1 | /* Trace calls through PLTs and show caller, callee, and parameters. |
6d7e8eda | 2 | Copyright (C) 2011-2023 Free Software Foundation, Inc. |
a9171047 | 3 | This file is part of the GNU C Library. |
a9171047 UD |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
a9171047 | 18 | |
32612615 | 19 | #include <err.h> |
a9171047 UD |
20 | #include <error.h> |
21 | #include <fcntl.h> | |
22 | #include <stdio.h> | |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
25 | #include <unistd.h> | |
26 | #include <sys/param.h> | |
27 | #include <sys/uio.h> | |
28 | ||
29 | #include <ldsodefs.h> | |
30 | ||
31 | ||
32 | extern const char *__progname; | |
33 | extern const char *__progname_full; | |
34 | ||
35 | ||
36 | /* List of objects to trace calls from. */ | |
37 | static const char *fromlist; | |
38 | /* List of objects to trace calls to. */ | |
39 | static const char *tolist; | |
40 | ||
41 | /* If non-zero, also trace returns of the calls. */ | |
42 | static int do_exit; | |
43 | /* If non-zero print PID for each line. */ | |
44 | static int print_pid; | |
45 | ||
46 | /* The output stream to use. */ | |
47 | static FILE *out_file; | |
48 | ||
49 | ||
50 | static int | |
51 | match_pid (pid_t pid, const char *which) | |
52 | { | |
53 | if (which == NULL || which[0] == '\0') | |
54 | { | |
55 | print_pid = 1; | |
56 | return 1; | |
57 | } | |
58 | ||
59 | char *endp; | |
60 | unsigned long n = strtoul (which, &endp, 0); | |
61 | return *endp == '\0' && n == pid; | |
62 | } | |
63 | ||
64 | ||
65 | static void | |
66 | init (void) | |
67 | { | |
68 | fromlist = getenv ("SOTRUSS_FROMLIST"); | |
69 | if (fromlist != NULL && fromlist[0] == '\0') | |
70 | fromlist = NULL; | |
71 | tolist = getenv ("SOTRUSS_TOLIST"); | |
72 | if (tolist != NULL && tolist[0] == '\0') | |
73 | tolist = NULL; | |
74 | do_exit = (getenv ("SOTRUSS_EXIT") ?: "")[0] != '\0'; | |
75 | ||
76 | /* Determine whether this process is supposed to be traced and if | |
77 | yes, whether we should print into a file. */ | |
78 | const char *which_process = getenv ("SOTRUSS_WHICH"); | |
79 | pid_t pid = getpid (); | |
80 | int out_fd = -1; | |
81 | if (match_pid (pid, which_process)) | |
82 | { | |
83 | const char *out_filename = getenv ("SOTRUSS_OUTNAME"); | |
84 | ||
85 | if (out_filename != NULL && out_filename[0] != 0) | |
86 | { | |
38d01bd6 | 87 | size_t out_filename_len = strlen (out_filename) + 13; |
a9171047 UD |
88 | char fullname[out_filename_len]; |
89 | char *endp = stpcpy (fullname, out_filename); | |
90 | if (which_process == NULL || which_process[0] == '\0') | |
38d01bd6 | 91 | snprintf (endp, 13, ".%ld", (long int) pid); |
a9171047 | 92 | |
a6d2f948 | 93 | out_fd = open64 (fullname, O_RDWR | O_CREAT | O_TRUNC, 0666); |
a9171047 UD |
94 | if (out_fd != -1) |
95 | print_pid = 0; | |
96 | } | |
97 | } | |
98 | ||
99 | /* If we do not write into a file write to stderr. Duplicate the | |
100 | descriptor so that we can keep printing in case the program | |
101 | closes stderr. Try first to allocate a descriptor with a value | |
102 | usually not used as to minimize interference with the | |
103 | program. */ | |
104 | if (out_fd == -1) | |
105 | { | |
a6d2f948 | 106 | out_fd = fcntl64 (STDERR_FILENO, F_DUPFD, 1000); |
a9171047 UD |
107 | if (out_fd == -1) |
108 | out_fd = dup (STDERR_FILENO); | |
109 | } | |
110 | ||
111 | if (out_fd != -1) | |
112 | { | |
113 | /* Convert file descriptor into a stream. */ | |
114 | out_file = fdopen (out_fd, "w"); | |
115 | if (out_file != NULL) | |
116 | setlinebuf (out_file); | |
117 | } | |
118 | } | |
119 | ||
120 | ||
121 | /* Audit interface verification. We also initialize everything if | |
122 | everything checks out OK. */ | |
123 | unsigned int | |
124 | la_version (unsigned int v) | |
125 | { | |
126 | if (v != LAV_CURRENT) | |
127 | error (1, 0, "cannot handle interface version %u", v); | |
128 | ||
129 | init (); | |
130 | ||
131 | return v; | |
132 | } | |
133 | ||
134 | ||
135 | /* Check whether a file name is on the colon-separated list of file | |
136 | names. */ | |
137 | static unsigned int | |
138 | match_file (const char *list, const char *name, size_t name_len, | |
139 | unsigned int mask) | |
140 | { | |
141 | if (list[0] == '\0') | |
142 | return 0; | |
143 | ||
144 | const char *cp = list; | |
145 | while (1) | |
146 | { | |
147 | if (strncmp (cp, name, name_len) == 0 | |
148 | && (cp[name_len] == ':' || cp[name_len] == '\0')) | |
149 | return mask; | |
150 | ||
151 | cp = strchr (cp, ':'); | |
152 | if (cp == NULL) | |
153 | return 0; | |
154 | ++cp; | |
155 | } | |
156 | } | |
157 | ||
158 | ||
159 | unsigned int | |
160 | la_objopen (struct link_map *map, Lmid_t lmid, uintptr_t *cookie) | |
161 | { | |
162 | if (out_file == NULL) | |
163 | return 0; | |
164 | ||
165 | const char *full_name = map->l_name ?: ""; | |
166 | if (full_name[0] == '\0') | |
167 | full_name = __progname_full; | |
168 | size_t full_name_len = strlen (full_name); | |
169 | const char *base_name = basename (full_name); | |
170 | if (base_name[0] == '\0') | |
171 | base_name = __progname; | |
172 | size_t base_name_len = strlen (base_name); | |
173 | ||
174 | int result = 0; | |
175 | const char *print_name = NULL; | |
176 | for (struct libname_list *l = map->l_libname; l != NULL; l = l->next) | |
177 | { | |
178 | if (print_name == NULL || (print_name[0] == '/' && l->name[0] != '/')) | |
179 | print_name = l->name; | |
180 | ||
181 | if (fromlist != NULL) | |
182 | result |= match_file (fromlist, l->name, strlen (l->name), | |
183 | LA_FLG_BINDFROM); | |
184 | ||
185 | if (tolist != NULL) | |
186 | result |= match_file (tolist, l->name, strlen (l->name),LA_FLG_BINDTO); | |
187 | } | |
188 | ||
189 | if (print_name == NULL) | |
190 | print_name = base_name; | |
191 | if (print_name[0] == '\0') | |
192 | print_name = __progname; | |
193 | ||
194 | /* We cannot easily get to the object name in the PLT handling | |
195 | functions. Use the cookie to get the string pointer passed back | |
196 | to us. */ | |
197 | *cookie = (uintptr_t) print_name; | |
198 | ||
199 | /* The object name has to be on the list of objects to trace calls | |
200 | from or that list must be empty. In the latter case we trace | |
201 | only calls from the main binary. */ | |
202 | if (fromlist == NULL) | |
203 | result |= map->l_name[0] == '\0' ? LA_FLG_BINDFROM : 0; | |
204 | else | |
205 | result |= (match_file (fromlist, full_name, full_name_len, | |
206 | LA_FLG_BINDFROM) | |
207 | | match_file (fromlist, base_name, base_name_len, | |
208 | LA_FLG_BINDFROM)); | |
209 | ||
210 | /* The object name has to be on the list of objects to trace calls | |
211 | to or that list must be empty. In the latter case we trace | |
212 | calls toall objects. */ | |
213 | if (tolist == NULL) | |
214 | result |= LA_FLG_BINDTO; | |
215 | else | |
216 | result |= (match_file (tolist, full_name, full_name_len, LA_FLG_BINDTO) | |
217 | | match_file (tolist, base_name, base_name_len, LA_FLG_BINDTO)); | |
218 | ||
219 | return result; | |
220 | } | |
221 | ||
222 | ||
223 | #if __ELF_NATIVE_CLASS == 32 | |
224 | # define la_symbind la_symbind32 | |
225 | typedef Elf32_Sym Elf_Sym; | |
226 | #else | |
227 | # define la_symbind la_symbind64 | |
228 | typedef Elf64_Sym Elf_Sym; | |
229 | #endif | |
230 | ||
231 | uintptr_t | |
232 | la_symbind (Elf_Sym *sym, unsigned int ndx, uintptr_t *refcook, | |
233 | uintptr_t *defcook, unsigned int *flags, const char *symname) | |
234 | { | |
32612615 AZ |
235 | if (*flags & LA_SYMB_NOPLTENTER) |
236 | warnx ("cannot trace PLT enter (bind-now enabled)"); | |
237 | ||
238 | if (do_exit && *flags & LA_SYMB_NOPLTEXIT) | |
239 | warnx ("cannot trace PLT exit (bind-now enabled)"); | |
240 | ||
a9171047 UD |
241 | if (!do_exit) |
242 | *flags = LA_SYMB_NOPLTEXIT; | |
243 | ||
244 | return sym->st_value; | |
245 | } | |
246 | ||
247 | ||
248 | static void | |
249 | print_enter (uintptr_t *refcook, uintptr_t *defcook, const char *symname, | |
250 | unsigned long int reg1, unsigned long int reg2, | |
251 | unsigned long int reg3, unsigned int flags) | |
252 | { | |
253 | char buf[3 * sizeof (pid_t) + 3]; | |
254 | buf[0] = '\0'; | |
255 | if (print_pid) | |
256 | snprintf (buf, sizeof (buf), "%5ld: ", (long int) getpid ()); | |
257 | ||
258 | fprintf (out_file, "%s%15s -> %-15s:%s%s(0x%lx, 0x%lx, 0x%lx)\n", | |
259 | buf, (char *) *refcook, (char *) *defcook, | |
260 | (flags & LA_SYMB_NOPLTEXIT) ? "*" : " ", symname, reg1, reg2, reg3); | |
261 | } | |
262 | ||
263 | ||
264 | #ifdef __i386__ | |
265 | Elf32_Addr | |
266 | la_i86_gnu_pltenter (Elf32_Sym *sym __attribute__ ((unused)), | |
267 | unsigned int ndx __attribute__ ((unused)), | |
268 | uintptr_t *refcook, uintptr_t *defcook, | |
269 | La_i86_regs *regs, unsigned int *flags, | |
270 | const char *symname, long int *framesizep) | |
271 | { | |
272 | unsigned long int *sp = (unsigned long int *) regs->lr_esp; | |
273 | ||
274 | print_enter (refcook, defcook, symname, sp[1], sp[2], sp[3], *flags); | |
275 | ||
276 | /* No need to copy anything, we will not need the parameters in any case. */ | |
277 | *framesizep = 0; | |
278 | ||
279 | return sym->st_value; | |
280 | } | |
281 | #elif defined __x86_64__ | |
282 | Elf64_Addr | |
283 | la_x86_64_gnu_pltenter (Elf64_Sym *sym __attribute__ ((unused)), | |
284 | unsigned int ndx __attribute__ ((unused)), | |
285 | uintptr_t *refcook, uintptr_t *defcook, | |
286 | La_x86_64_regs *regs, unsigned int *flags, | |
287 | const char *symname, long int *framesizep) | |
288 | { | |
289 | print_enter (refcook, defcook, symname, | |
290 | regs->lr_rdi, regs->lr_rsi, regs->lr_rdx, *flags); | |
291 | ||
292 | /* No need to copy anything, we will not need the parameters in any case. */ | |
293 | *framesizep = 0; | |
294 | ||
295 | return sym->st_value; | |
296 | } | |
2d2cd515 DM |
297 | #elif defined __sparc__ && !defined __arch64__ |
298 | Elf32_Addr | |
299 | la_sparc32_gnu_pltenter (Elf32_Sym *sym __attribute__ ((unused)), | |
300 | unsigned int ndx __attribute__ ((unused)), | |
301 | uintptr_t *refcook, uintptr_t *defcook, | |
302 | La_sparc32_regs *regs, unsigned int *flags, | |
303 | const char *symname, long int *framesizep) | |
304 | { | |
305 | print_enter (refcook, defcook, symname, | |
306 | regs->lr_reg[0], regs->lr_reg[1], regs->lr_reg[2], | |
307 | *flags); | |
308 | ||
309 | /* No need to copy anything, we will not need the parameters in any case. */ | |
310 | *framesizep = 0; | |
311 | ||
312 | return sym->st_value; | |
313 | } | |
314 | #elif defined __sparc__ && defined __arch64__ | |
315 | Elf64_Addr | |
316 | la_sparc64_gnu_pltenter (Elf64_Sym *sym __attribute__ ((unused)), | |
317 | unsigned int ndx __attribute__ ((unused)), | |
318 | uintptr_t *refcook, uintptr_t *defcook, | |
319 | La_sparc64_regs *regs, unsigned int *flags, | |
320 | const char *symname, long int *framesizep) | |
321 | { | |
322 | print_enter (refcook, defcook, symname, | |
323 | regs->lr_reg[0], regs->lr_reg[1], regs->lr_reg[2], | |
324 | *flags); | |
325 | ||
326 | /* No need to copy anything, we will not need the parameters in any case. */ | |
327 | *framesizep = 0; | |
328 | ||
329 | return sym->st_value; | |
330 | } | |
a9171047 UD |
331 | #elif !defined HAVE_ARCH_PLTENTER |
332 | # warning "pltenter for architecture not supported" | |
333 | #endif | |
334 | ||
335 | ||
336 | static void | |
337 | print_exit (uintptr_t *refcook, uintptr_t *defcook, const char *symname, | |
338 | unsigned long int reg) | |
339 | { | |
340 | char buf[3 * sizeof (pid_t) + 3]; | |
341 | buf[0] = '\0'; | |
342 | if (print_pid) | |
343 | snprintf (buf, sizeof (buf), "%5ld: ", (long int) getpid ()); | |
344 | ||
2d2cd515 | 345 | fprintf (out_file, "%s%15s -> %-15s:%s%s - 0x%lx\n", |
a9171047 UD |
346 | buf, (char *) *refcook, (char *) *defcook, " ", symname, reg); |
347 | } | |
348 | ||
349 | ||
350 | #ifdef __i386__ | |
351 | unsigned int | |
352 | la_i86_gnu_pltexit (Elf32_Sym *sym, unsigned int ndx, uintptr_t *refcook, | |
353 | uintptr_t *defcook, const struct La_i86_regs *inregs, | |
354 | struct La_i86_retval *outregs, const char *symname) | |
355 | { | |
356 | print_exit (refcook, defcook, symname, outregs->lrv_eax); | |
357 | ||
358 | return 0; | |
359 | } | |
360 | #elif defined __x86_64__ | |
361 | unsigned int | |
362 | la_x86_64_gnu_pltexit (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook, | |
363 | uintptr_t *defcook, const struct La_x86_64_regs *inregs, | |
364 | struct La_x86_64_retval *outregs, const char *symname) | |
365 | { | |
366 | print_exit (refcook, defcook, symname, outregs->lrv_rax); | |
367 | ||
368 | return 0; | |
369 | } | |
2d2cd515 DM |
370 | #elif defined __sparc__ && !defined __arch64__ |
371 | unsigned int | |
372 | la_sparc32_gnu_pltexit (Elf32_Sym *sym, unsigned int ndx, uintptr_t *refcook, | |
373 | uintptr_t *defcook, const struct La_sparc32_regs *inregs, | |
374 | struct La_sparc32_retval *outregs, const char *symname) | |
375 | { | |
376 | print_exit (refcook, defcook, symname, outregs->lrv_reg[0]); | |
377 | ||
378 | return 0; | |
379 | } | |
380 | #elif defined __sparc__ && defined __arch64__ | |
381 | unsigned int | |
382 | la_sparc64_gnu_pltexit (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook, | |
383 | uintptr_t *defcook, const struct La_sparc64_regs *inregs, | |
384 | struct La_sparc64_retval *outregs, const char *symname) | |
385 | { | |
386 | print_exit (refcook, defcook, symname, outregs->lrv_reg[0]); | |
387 | ||
388 | return 0; | |
389 | } | |
a9171047 UD |
390 | #elif !defined HAVE_ARCH_PLTEXIT |
391 | # warning "pltexit for architecture not supported" | |
392 | #endif |