1 /* $OpenBSD: ldd.c,v 1.26 2023/08/15 13:50:53 deraadt Exp $ */
2 /*
3 * Copyright (c) 2001 Artur Grabowski <art@openbsd.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
16 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
17 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
18 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
21 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
23 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <elf.h>
30 #include <err.h>
31 #include <fcntl.h>
32 #include <string.h>
33 #include <signal.h>
34 #include <unistd.h>
35 #include <limits.h>
36 #include <dlfcn.h>
37 #include <errno.h>
38
39 #include <sys/stat.h>
40 #include <sys/mman.h>
41 #include <sys/wait.h>
42
43 int usage(void);
44 int doit(char *);
45
46 int
main(int argc,char ** argv)47 main(int argc, char **argv)
48 {
49 int c, xflag, ret;
50
51 if (pledge("stdio rpath proc exec prot_exec", NULL) == -1)
52 err(1, "pledge");
53
54 xflag = 0;
55 while ((c = getopt(argc, argv, "x")) != -1) {
56 switch (c) {
57 case 'x':
58 xflag = 1;
59 break;
60 default:
61 usage();
62 /*NOTREACHED*/
63 }
64 }
65
66 if (xflag)
67 errx(1, "-x not yet implemented");
68
69 argc -= optind;
70 argv += optind;
71
72 if (argc == 0)
73 usage();
74
75 if (setenv("LD_TRACE_LOADED_OBJECTS", "true", 1) < 0)
76 err(1, "setenv(LD_TRACE_LOADED_OBJECTS)");
77
78 ret = 0;
79 while (argc--) {
80 ret |= doit(*argv);
81 argv++;
82 }
83
84 return ret;
85 }
86
87 int
usage(void)88 usage(void)
89 {
90 extern char *__progname;
91
92 fprintf(stderr, "usage: %s program ...\n", __progname);
93 exit(1);
94 }
95
96
97 int
doit(char * name)98 doit(char *name)
99 {
100 Elf_Ehdr ehdr;
101 Elf_Phdr *phdr;
102 size_t size;
103 int fd, i, status, interp=0;
104 char buf[PATH_MAX];
105 struct stat st;
106 void * dlhandle;
107
108 if ((fd = open(name, O_RDONLY)) < 0) {
109 warn("%s", name);
110 return 1;
111 }
112
113 if (fstat(fd, &st) == -1) {
114 warn("%s", name);
115 close(fd);
116 return 1;
117 }
118
119 if (!S_ISREG(st.st_mode)) {
120 warnx("%s: not a regular file", name);
121 close(fd);
122 return 1;
123 }
124
125 if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr)) {
126 warnx("%s: incomplete ELF header", name);
127 close(fd);
128 return 1;
129 }
130
131 if (!IS_ELF(ehdr) || ehdr.e_machine != ELF_TARG_MACH) {
132 warnx("%s: not an ELF executable", name);
133 close(fd);
134 return 1;
135 }
136
137 if (ehdr.e_phnum == 0 || ehdr.e_phentsize == 0) {
138 warnx("%s: missing program header", name);
139 close(fd);
140 return 1;
141 }
142
143 if ((phdr = reallocarray(NULL, ehdr.e_phnum, sizeof(Elf_Phdr))) == NULL)
144 err(1, "reallocarray");
145 size = ehdr.e_phnum * sizeof(Elf_Phdr);
146
147 if (pread(fd, phdr, size, ehdr.e_phoff) != size) {
148 warnx("%s: incomplete program header", name);
149 close(fd);
150 free(phdr);
151 return 1;
152 }
153 close(fd);
154
155 for (i = 0; i < ehdr.e_phnum; i++)
156 if (phdr[i].p_type == PT_INTERP) {
157 interp = 1;
158 break;
159 }
160 free(phdr);
161
162 printf("%s:\n", name);
163 fflush(stdout);
164 switch (fork()) {
165 case -1:
166 err(1, "fork");
167 case 0:
168 if (ehdr.e_type == ET_DYN && !interp) {
169 if (pledge("stdio rpath prot_exec", NULL) == -1)
170 err(1, "pledge");
171 if (realpath(name, buf) == NULL) {
172 printf("realpath(%s): %s", name,
173 strerror(errno));
174 fflush(stdout);
175 _exit(1);
176 }
177 dlhandle = dlopen(buf, RTLD_TRACE);
178 if (dlhandle == NULL) {
179 printf("%s\n", dlerror());
180 fflush(stdout);
181 _exit(1);
182 }
183 _exit(0);
184 }
185
186 if (pledge("stdio rpath exec", "stdio rpath") == -1)
187 err(1, "pledge");
188 if (i == ehdr.e_phnum) {
189 printf("not a dynamic executable\n");
190 fflush(stdout);
191 _exit(0);
192 }
193 execl(name, name, (char *)NULL);
194 perror(name);
195 _exit(1);
196 default:
197 if (wait(&status) < 0) {
198 warn("wait");
199 return 1;
200 }
201 if (WIFSIGNALED(status)) {
202 if (WTERMSIG(status) == SIGINT)
203 return 1;
204 fprintf(stderr, "%s: signal %d\n", name,
205 WTERMSIG(status));
206 return 1;
207 }
208 if (WEXITSTATUS(status)) {
209 fprintf(stderr, "%s: exit status %d\n", name,
210 WEXITSTATUS(status));
211 return 1;
212 }
213 }
214
215 return 0;
216 }
217