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) 2000-2012 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_xarray.h"
39#include "pub_core_clientstate.h"
40#include "pub_core_mallocfree.h"    // VG_(strdup)
41#include "pub_core_ume.h"           // self
42
43#include "priv_ume.h"
44
45Bool VG_(match_script)(Char *hdr, Int len)
46{
47   Char* end    = hdr + len;
48   Char* interp = hdr + 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 && VG_(isspace)(*interp)) 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 */
79Int VG_(load_script)(Int fd, const HChar* name, ExeInfo* info)
80{
81   Char  hdr[4096];
82   Int   len = 4096;
83   Int   eol;
84   Char* interp;
85   Char* end;
86   Char* cp;
87   Char* 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 && VG_(isspace)(*interp))
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] = (char *)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