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, see <http://www.gnu.org/licenses/>.
  26
  27    The GNU General Public License is contained in the file COPYING.
  28 */
  29
  30 #include "pub_core_basics.h"
  31 #include "pub_core_vki.h"
  32
  33 #include "pub_core_libcbase.h"
  34 #include "pub_core_libcassert.h"    // VG_(exit), vg_assert
  35 #include "pub_core_libcfile.h"      // VG_(close) et al
  36 #include "pub_core_libcprint.h"
  37 #include "pub_core_clientstate.h"   // VG_(args_the_exename)
  38 #include "pub_core_mallocfree.h"    // VG_(strdup)
  39 #include "pub_core_ume.h"           // self
  40
  41 #include "priv_ume.h"
  42
  43 /* Return true, if the first line begins with #! and contains an
  44    interpreter. */
  45 Bool VG_(match_script)(const void *hdr, SizeT len)
  46 {
  47    const HChar* script = hdr;
  48    const HChar* end    = script + len;
  49    const HChar* interp = script + 2;
  50
  51    if (len < 2) return False;
  52    if (0 != VG_(memcmp)(hdr, "#!", 2)) return False;
  53
  54    // Find interpreter name, which may be absolute or relative.
  55    // First, skip over any space between the #! and the start of the
  56    // 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    // No interpreter found.
  63    if (*interp == '\n') return False;
  64
  65    return True;   // looks like a #! script
  66 }
  67
  68
  69 /* returns: 0 = success, non-0 is failure */
  70 Int VG_(load_script)(Int fd, const HChar* name, ExeInfo* info)
  71 {
  72    HChar  hdr[4096];
  73    Int    len = sizeof hdr;
  74    Int    eol;
  75    HChar* interp;
  76    HChar* end;
  77    HChar* cp;
  78    HChar* arg = NULL;
  79    SysRes res;
  80
  81    // Read the first part of the file.
  82    res = VG_(pread)(fd, hdr, len, 0);
  83    if (sr_isError(res)) {
  84       VG_(close)(fd);
  85       return VKI_EACCES;
  86    } else {
  87       len = sr_Res(res);
  88    }
  89
  90    vg_assert('#' == hdr[0] && '!' == hdr[1]);
  91
  92    end    = hdr + len;
  93    interp = hdr + 2;
  94    while (interp < end && (*interp == ' ' || *interp == '\t'))
  95       interp++;
  96
  97    /* skip over interpreter name */
  98    for (cp = interp; cp < end && !VG_(isspace)(*cp); cp++)
  99       ;
 100
 101    eol = (*cp == '\n');
 102
 103    *cp++ = '\0';
 104
 105    if (!eol && cp < end) {
 106       /* skip space before arg */
 107       while (cp < end && VG_(isspace)(*cp) && *cp != '\n')
 108          cp++;
 109
 110       /* arg is from here to eol */
 111       arg = cp;
 112       while (cp < end && *cp != '\n')
 113          cp++;
 114       *cp = '\0';
 115    }
 116    VG_(free)(info->interp_name);
 117    info->interp_name = VG_(strdup)("ume.ls.1", interp);
 118    vg_assert(NULL != info->interp_name);
 119    if (arg != NULL && *arg != '\0') {
 120       info->interp_args = VG_(strdup)("ume.ls.2", arg);
 121       vg_assert(NULL != info->interp_args);
 122    }
 123
 124    if (info->argv && info->argv[0] != NULL)
 125      info->argv[0] = name;
 126
 127    VG_(args_the_exename) = name;
 128
 129    if (0)
 130       VG_(printf)("#! script: interp_name=\"%s\" interp_args=\"%s\"\n",
 131                   info->interp_name, info->interp_args);
 132
 133    return VG_(do_exec_inner)(interp, info);
 134 }
 135
 136 /*--------------------------------------------------------------------*/
 137 /*--- end                                                          ---*/
 138 /*--------------------------------------------------------------------*/