1
2 /*--------------------------------------------------------------------*/
3 /*--- Startup: search PATH for an executable initimg-pathscan.c ---*/
4 /*--------------------------------------------------------------------*/
5
6 /*
7 This file is part of Valgrind, a dynamic binary instrumentation
8 framework.
9
10 Copyright (C) 2000-2017 Julian Seward
11 jseward@acm.org
12
13 This program is free software; you can redistribute it and/or
14 modify it under the terms of the GNU General Public License as
15 published by the Free Software Foundation; either version 2 of the
16 License, or (at your option) any later version.
17
18 This program is distributed in the hope that it will be useful, but
19 WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 General Public License for more details.
22
23 You should have received a copy of the GNU General Public License
24 along with this program; if not, write to the Free Software
25 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26 02111-1307, USA.
27
28 The GNU General Public License is contained in the file COPYING.
29 */
30
31 #include "pub_core_basics.h"
32 #include "pub_core_libcbase.h"
33 #include "pub_core_libcassert.h"
34 #include "pub_core_libcfile.h"
35 #include "pub_core_libcproc.h"
36 #include "pub_core_libcprint.h"
37 #include "pub_core_mallocfree.h"
38 #include "pub_core_initimg.h" /* self */
39
40 #include "priv_initimg_pathscan.h"
41
42
43 /*====================================================================*/
44 /*=== Find executable ===*/
45 /*====================================================================*/
46
47 /* Scan a colon-separated list, and call a function on each element.
48 The string must be mutable, because we insert a temporary '\0', but
49 the string will end up unmodified. (*func) should return True if it
50 doesn't need to see any more.
51
52 This routine will return True if (*func) returns True and False if
53 it reaches the end of the list without that happening.
54 */
scan_colsep(HChar * colsep,Bool (* func)(const HChar *))55 static Bool scan_colsep(HChar *colsep, Bool (*func)(const HChar *))
56 {
57 HChar *cp, *entry;
58 int end;
59
60 if (colsep == NULL ||
61 *colsep == '\0')
62 return False;
63
64 entry = cp = colsep;
65
66 do {
67 end = (*cp == '\0');
68
69 if (*cp == ':' || *cp == '\0') {
70 HChar save = *cp;
71
72 *cp = '\0';
73 if ((*func)(entry)) {
74 *cp = save;
75 return True;
76 }
77 *cp = save;
78 entry = cp+1;
79 }
80 cp++;
81 } while(!end);
82
83 return False;
84 }
85
86
87 static const HChar *executable_name_in;
88 static HChar *executable_name_out;
89
match_executable(const HChar * entry)90 static Bool match_executable(const HChar *entry)
91 {
92 /* empty ENTRY element means '.' */
93 if (*entry == '\0')
94 entry = ".";
95
96 HChar buf[VG_(strlen)(entry) + 1 + VG_(strlen)(executable_name_in) + 1];
97
98 VG_(sprintf)(buf, "%s/%s", entry, executable_name_in);
99
100 // Don't match directories
101 if (VG_(is_dir)(buf))
102 return False;
103
104 // If we match an executable, we choose that immediately. If we find a
105 // matching non-executable we remember it but keep looking for an
106 // matching executable later in the path.
107 if (VG_(access)(buf, True/*r*/, False/*w*/, True/*x*/) == 0) {
108 VG_(free)(executable_name_out);
109 executable_name_out = VG_(strdup)("match_executable", buf);
110 return True; // Stop looking
111 } else if (VG_(access)(buf, True/*r*/, False/*w*/, False/*x*/) == 0
112 && executable_name_out == NULL)
113 {
114 executable_name_out = VG_(strdup)("match_executable", buf);
115 return False; // Keep looking
116 } else {
117 return False; // Keep looking
118 }
119 }
120
121 // Returns NULL if it wasn't found.
ML_(find_executable)122 const HChar* ML_(find_executable) ( const HChar* exec )
123 {
124 vg_assert(NULL != exec);
125
126 if (VG_(strchr)(exec, '/')) {
127 // Has a '/' - use the name as is even if exec is a directory.
128 // The reason is that we get a better error message this way:
129 // valgrind ./foo
130 // valgrind: ./foo: is a directory
131 return exec;
132 }
133
134 // No '/' - we need to search the path
135 HChar* path = VG_(getenv)("PATH");
136
137 VG_(free)(executable_name_out);
138
139 executable_name_in = exec;
140 executable_name_out = NULL;
141 scan_colsep(path, match_executable);
142
143 return executable_name_out;
144 }
145
146 /*--------------------------------------------------------------------*/
147 /*--- end ---*/
148 /*--------------------------------------------------------------------*/
149