coregrind/m_ume/script.c

   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. */
  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 */
  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 /*--------------------------------------------------------------------*/