1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2011, Joyent, Inc. All rights reserved.
24  * Copyright (c) 2011, Robert Mustacchi, Inc. All rights reserved.
25  * Copyright 2013, Richard Lowe.
26  */
27 
28 #include <err.h>
29 #include <fcntl.h>
30 #include <gelf.h>
31 #include <libctf.h>
32 #include <saveargs.h>
33 #include <stdarg.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <strings.h>
37 #include <unistd.h>
38 
39 extern const char *__progname;
40 
41 typedef struct symtab_sym {
42 	GElf_Sym ss_sym;
43 	char *ss_name;
44 	ctf_funcinfo_t ss_finfo;
45 	uint8_t *ss_data;
46 	size_t ss_size;
47 } symtab_sym_t;
48 
49 static void
walk_symtab(Elf * elf,char * fname,ctf_file_t * fp,void (* callback)(ctf_file_t *,symtab_sym_t *))50 walk_symtab(Elf *elf, char *fname, ctf_file_t *fp,
51     void (*callback)(ctf_file_t *, symtab_sym_t *))
52 {
53 	Elf_Scn *stab = NULL;
54 	Elf_Scn *text = NULL;
55 	Elf_Data *stabdata = NULL;
56 	Elf_Data *textdata = NULL;
57 	GElf_Ehdr ehdr;
58 	GElf_Shdr stabshdr;
59 	GElf_Shdr textshdr;
60 	int foundtext = 0, foundstab = 0;
61 	symtab_sym_t ss;
62 
63 	if ((gelf_getehdr(elf, &ehdr)) == NULL)
64 		errx(1, "could not read ELF header from %s\n",
65 		    fname);
66 
67 	while ((stab = elf_nextscn(elf, stab)) != NULL) {
68 		(void) gelf_getshdr(stab, &stabshdr);
69 
70 		if (stabshdr.sh_type == SHT_SYMTAB) {
71 			foundstab = 1;
72 			break;
73 		}
74 	}
75 
76 	while ((text = elf_nextscn(elf, text)) != NULL) {
77 		(void) gelf_getshdr(text, &textshdr);
78 
79 		if (strcmp(".text", elf_strptr(elf,
80 		    ehdr.e_shstrndx, (size_t)textshdr.sh_name)) == 0) {
81 			foundtext = 1;
82 			break;
83 		}
84 	}
85 
86 	if (!foundstab || !foundtext)
87 		return;
88 
89 	stabdata = elf_getdata(stab, NULL);
90 	textdata = elf_rawdata(text,  NULL);
91 	for (unsigned symdx = 0;
92 	    symdx < (stabshdr.sh_size / stabshdr.sh_entsize);
93 	    symdx++) {
94 		(void) gelf_getsym(stabdata, symdx, &ss.ss_sym);
95 
96 		if ((GELF_ST_TYPE(ss.ss_sym.st_info) != STT_FUNC) ||
97 		    (ss.ss_sym.st_shndx == SHN_UNDEF))
98 			continue;
99 
100 		ss.ss_name = elf_strptr(elf, stabshdr.sh_link,
101 		    ss.ss_sym.st_name);
102 		ss.ss_data = ((uint8_t *)(textdata->d_buf)) +
103 		    (ss.ss_sym.st_value - textshdr.sh_addr);
104 
105 		if (ctf_func_info(fp, symdx, &ss.ss_finfo) == CTF_ERR) {
106 			fprintf(stderr, "failed to get funcinfo for: %s\n",
107 			    ss.ss_name);
108 			continue;
109 		}
110 
111 		(void) callback(fp, &ss);
112 	}
113 }
114 
115 void
check_sym(ctf_file_t * ctfp,symtab_sym_t * ss)116 check_sym(ctf_file_t *ctfp, symtab_sym_t *ss)
117 {
118 	int rettype = ctf_type_kind(ctfp, ss->ss_finfo.ctc_return);
119 	int start_index = 0;
120 
121 	if (ss->ss_finfo.ctc_argc == 0) /* No arguments, no point */
122 		return;
123 
124 	if (((rettype == CTF_K_STRUCT) || (rettype == CTF_K_UNION)) &&
125 	    ctf_type_size(ctfp, ss->ss_finfo.ctc_return) > 16)
126 		start_index = 1;
127 
128 	if (saveargs_has_args(ss->ss_data, ss->ss_sym.st_size,
129 	    ss->ss_finfo.ctc_argc, start_index) != SAVEARGS_NO_ARGS)
130 		printf("%s has %d saved args\n", ss->ss_name,
131 		    ss->ss_finfo.ctc_argc);
132 }
133 
134 int
main(int argc,char ** argv)135 main(int argc, char **argv)
136 {
137 	Elf		*elf;
138 	ctf_file_t	*ctfp;
139 	int errp, fd;
140 
141 	if (ctf_version(CTF_VERSION) == -1)
142 		errx(1, "mismatched libctf versions\n");
143 
144 	if (elf_version(EV_CURRENT) == EV_NONE)
145 		errx(1, "mismatched libelf versions\n");
146 
147 	if (argc != 2)
148 		errx(2, "usage: %s <file>\n", __progname);
149 
150 	if ((ctfp = ctf_open(argv[1], &errp)) == NULL)
151 		errx(1, "failed to ctf_open file: %s: %s\n", argv[1],
152 		    ctf_errmsg(errp));
153 
154 	if ((fd = open(argv[1], O_RDONLY)) == -1)
155 		errx(1, "could not open %s\n", argv[1]);
156 
157 	if ((elf = elf_begin(fd, ELF_C_READ, NULL)) == NULL)
158 		errx(1, "could not interpret ELF from %s\n",
159 		    argv[1]);
160 
161 	walk_symtab(elf, argv[1], ctfp, check_sym);
162 
163 	(void) elf_end(elf);
164 	(void) close(fd);
165 
166 	return (0);
167 }
168