1
2 /*--------------------------------------------------------------------*/
3 /*--- User-mode execve() for #! scripts. m_ume_script.c ---*/
4 /*--------------------------------------------------------------------*/
5
6 /*
7 This file is part of Valgrind, a dynamic binary instrumentation
8 framework.
9
10 Copyright (C) 2000-2013 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_vki.h"
33
34 #include "pub_core_libcbase.h"
35 #include "pub_core_libcassert.h" // VG_(exit), vg_assert
36 #include "pub_core_libcfile.h" // VG_(close) et al
37 #include "pub_core_libcprint.h"
38 #include "pub_core_clientstate.h" // VG_(args_the_exename)
39 #include "pub_core_mallocfree.h" // VG_(strdup)
40 #include "pub_core_ume.h" // self
41
42 #include "priv_ume.h"
43
VG_(match_script)44 Bool VG_(match_script)(const void *hdr, SizeT len)
45 {
46 const HChar* script = hdr;
47 const HChar* end = script + len;
48 const HChar* interp = script + 2;
49
50 // len < 4: need '#', '!', plus at least a '/' and one more char
51 if (len < 4) return False;
52 if (0 != VG_(memcmp)(hdr, "#!", 2)) return False;
53
54 // Find interpreter name, make sure it's an absolute path (starts with
55 // '/') and has at least one more char. First, skip over any space
56 // between the #! and the start of the interpreter name
57 while (interp < end && (*interp == ' ' || *interp == '\t')) interp++;
58
59 // overrun?
60 if (interp >= end) return False; // can't find start of interp name
61
62 // interp should now point at the /
63 if (*interp != '/') return False; // absolute path only for interpreter
64
65 // check for something plausible after the /
66 interp++;
67 if (interp >= end) return False;
68 if (VG_(isspace)(*interp)) return False;
69
70 // Here we should get the full interpreter name and check it with
71 // check_executable(). See the "EXEC FAILED" failure when running shell
72 // for an example.
73
74 return True; // looks like a #! script
75 }
76
77
78 /* returns: 0 = success, non-0 is failure */
VG_(load_script)79 Int VG_(load_script)(Int fd, const HChar* name, ExeInfo* info)
80 {
81 HChar hdr[4096];
82 Int len = sizeof hdr;
83 Int eol;
84 HChar* interp;
85 HChar* end;
86 HChar* cp;
87 HChar* arg = NULL;
88 SysRes res;
89
90 // Read the first part of the file.
91 res = VG_(pread)(fd, hdr, len, 0);
92 if (sr_isError(res)) {
93 VG_(close)(fd);
94 return VKI_EACCES;
95 } else {
96 len = sr_Res(res);
97 }
98
99 vg_assert('#' == hdr[0] && '!' == hdr[1]);
100
101 end = hdr + len;
102 interp = hdr + 2;
103 while (interp < end && (*interp == ' ' || *interp == '\t'))
104 interp++;
105
106 vg_assert(*interp == '/'); /* absolute path only for interpreter */
107
108 /* skip over interpreter name */
109 for (cp = interp; cp < end && !VG_(isspace)(*cp); cp++)
110 ;
111
112 eol = (*cp == '\n');
113
114 *cp++ = '\0';
115
116 if (!eol && cp < end) {
117 /* skip space before arg */
118 while (cp < end && VG_(isspace)(*cp) && *cp != '\n')
119 cp++;
120
121 /* arg is from here to eol */
122 arg = cp;
123 while (cp < end && *cp != '\n')
124 cp++;
125 *cp = '\0';
126 }
127
128 info->interp_name = VG_(strdup)("ume.ls.1", interp);
129 vg_assert(NULL != info->interp_name);
130 if (arg != NULL && *arg != '\0') {
131 info->interp_args = VG_(strdup)("ume.ls.2", arg);
132 vg_assert(NULL != info->interp_args);
133 }
134
135 if (info->argv && info->argv[0] != NULL)
136 info->argv[0] = name;
137
138 VG_(args_the_exename) = name;
139
140 if (0)
141 VG_(printf)("#! script: interp_name=\"%s\" interp_args=\"%s\"\n",
142 info->interp_name, info->interp_args);
143
144 return VG_(do_exec_inner)(interp, info);
145 }
146
147 /*--------------------------------------------------------------------*/
148 /*--- end ---*/
149 /*--------------------------------------------------------------------*/
150