1 /* -*- mode: C; c-basic-offset: 3; -*- */
2
3 /*--------------------------------------------------------------------*/
4 /*--- User-mode execve() for #! scripts. m_ume_script.c ---*/
5 /*--------------------------------------------------------------------*/
6
7 /*
8 This file is part of Valgrind, a dynamic binary instrumentation
9 framework.
10
11 Copyright (C) 2000-2017 Julian Seward
12 jseward@acm.org
13
14 This program is free software; you can redistribute it and/or
15 modify it under the terms of the GNU General Public License as
16 published by the Free Software Foundation; either version 2 of the
17 License, or (at your option) any later version.
18
19 This program is distributed in the hope that it will be useful, but
20 WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 General Public License for more details.
23
24 You should have received a copy of the GNU General Public License
25 along with this program; if not, write to the Free Software
26 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
27 02111-1307, USA.
28
29 The GNU General Public License is contained in the file COPYING.
30 */
31
32 #include "pub_core_basics.h"
33 #include "pub_core_vki.h"
34
35 #include "pub_core_libcbase.h"
36 #include "pub_core_libcassert.h" // VG_(exit), vg_assert
37 #include "pub_core_libcfile.h" // VG_(close) et al
38 #include "pub_core_libcprint.h"
39 #include "pub_core_clientstate.h" // VG_(args_the_exename)
40 #include "pub_core_mallocfree.h" // VG_(strdup)
41 #include "pub_core_ume.h" // self
42
43 #include "priv_ume.h"
44
45 /* Return true, if the first line begins with #! and contains an
46 interpreter. */
VG_(match_script)47 Bool VG_(match_script)(const void *hdr, SizeT len)
48 {
49 const HChar* script = hdr;
50 const HChar* end = script + len;
51 const HChar* interp = script + 2;
52
53 if (len < 2) return False;
54 if (0 != VG_(memcmp)(hdr, "#!", 2)) return False;
55
56 // Find interpreter name, which may be absolute or relative.
57 // First, skip over any space between the #! and the start of the
58 // interpreter name
59 while (interp < end && (*interp == ' ' || *interp == '\t')) interp++;
60
61 // overrun?
62 if (interp >= end) return False; // can't find start of interp name
63
64 // No interpreter found.
65 if (*interp == '\n') return False;
66
67 return True; // looks like a #! script
68 }
69
70
71 /* returns: 0 = success, non-0 is failure */
VG_(load_script)72 Int VG_(load_script)(Int fd, const HChar* name, ExeInfo* info)
73 {
74 HChar hdr[4096];
75 Int len = sizeof hdr;
76 Int eol;
77 HChar* interp;
78 HChar* end;
79 HChar* cp;
80 HChar* arg = NULL;
81 SysRes res;
82
83 // Read the first part of the file.
84 res = VG_(pread)(fd, hdr, len, 0);
85 if (sr_isError(res)) {
86 VG_(close)(fd);
87 return VKI_EACCES;
88 } else {
89 len = sr_Res(res);
90 }
91
92 vg_assert('#' == hdr[0] && '!' == hdr[1]);
93
94 end = hdr + len;
95 interp = hdr + 2;
96 while (interp < end && (*interp == ' ' || *interp == '\t'))
97 interp++;
98
99 /* skip over interpreter name */
100 for (cp = interp; cp < end && !VG_(isspace)(*cp); cp++)
101 ;
102
103 eol = (*cp == '\n');
104
105 *cp++ = '\0';
106
107 if (!eol && cp < end) {
108 /* skip space before arg */
109 while (cp < end && VG_(isspace)(*cp) && *cp != '\n')
110 cp++;
111
112 /* arg is from here to eol */
113 arg = cp;
114 while (cp < end && *cp != '\n')
115 cp++;
116 *cp = '\0';
117 }
118 VG_(free)(info->interp_name);
119 info->interp_name = VG_(strdup)("ume.ls.1", interp);
120 vg_assert(NULL != info->interp_name);
121 if (arg != NULL && *arg != '\0') {
122 info->interp_args = VG_(strdup)("ume.ls.2", arg);
123 vg_assert(NULL != info->interp_args);
124 }
125
126 if (info->argv && info->argv[0] != NULL)
127 info->argv[0] = name;
128
129 VG_(args_the_exename) = name;
130
131 if (0)
132 VG_(printf)("#! script: interp_name=\"%s\" interp_args=\"%s\"\n",
133 info->interp_name, info->interp_args);
134
135 return VG_(do_exec_inner)(interp, info);
136 }
137
138 /*--------------------------------------------------------------------*/
139 /*--- end ---*/
140 /*--------------------------------------------------------------------*/
141