tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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mangle.c (3656B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this
      3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 
      5 /*
      6 * Test program to mangle 1 bit in a binary
      7 */
      8 
      9 #include "nspr.h"
     10 #include "plstr.h"
     11 #include "plgetopt.h"
     12 #include "prio.h"
     13 
     14 static PRFileDesc *pr_stderr;
     15 static void
     16 usage(char *program_name)
     17 {
     18 
     19    PR_fprintf(pr_stderr, "Usage:");
     20    PR_fprintf(pr_stderr, "%s -i shared_library_name -o byte_offset -b bit\n", program_name);
     21 }
     22 
     23 int
     24 main(int argc, char **argv)
     25 {
     26    /* buffers and locals */
     27    PLOptState *optstate;
     28    char *programName;
     29    char cbuf;
     30 
     31    /* parameter set variables */
     32    const char *libFile = NULL;
     33    int bitOffset = -1;
     34 
     35    /* return values */
     36    int retval = 2; /* 0 - test succeeded.
     37                     * 1 - illegal args
     38                     * 2 - function failed */
     39    PRFileDesc *fd = NULL;
     40    int bytesRead;
     41    int bytesWritten;
     42    PROffset32 offset = -1;
     43    PROffset32 pos;
     44 
     45    programName = PL_strrchr(argv[0], '/');
     46    programName = programName ? (programName + 1) : argv[0];
     47 
     48    pr_stderr = PR_STDERR;
     49 
     50    optstate = PL_CreateOptState(argc, argv, "i:o:b:");
     51    if (optstate == NULL) {
     52        return 1;
     53    }
     54 
     55    while (PL_GetNextOpt(optstate) == PL_OPT_OK) {
     56        switch (optstate->option) {
     57            case 'i':
     58                libFile = optstate->value;
     59                break;
     60 
     61            case 'o':
     62                offset = atoi(optstate->value);
     63                break;
     64 
     65            case 'b':
     66                bitOffset = atoi(optstate->value);
     67                break;
     68        }
     69    }
     70 
     71    if (libFile == NULL) {
     72        usage(programName);
     73        return 1;
     74    }
     75    if ((bitOffset >= 8) || (bitOffset < 0)) {
     76        usage(programName);
     77        return 1;
     78    }
     79 
     80    /* open the target signature file */
     81    fd = PR_OpenFile(libFile, PR_RDWR, 0666);
     82    if (fd == NULL) {
     83        /* lperror(libFile); */
     84        PR_fprintf(pr_stderr, "Couldn't Open %s\n", libFile);
     85        goto loser;
     86    }
     87 
     88    if (offset < 0) { /* convert to positive offset */
     89        pos = PR_Seek(fd, offset, PR_SEEK_END);
     90        if (pos == -1) {
     91            PR_fprintf(pr_stderr, "Seek for read on %s (to %d) failed\n",
     92                       libFile, offset);
     93            goto loser;
     94        }
     95        offset = pos;
     96    }
     97 
     98    /* read the byte */
     99    pos = PR_Seek(fd, offset, PR_SEEK_SET);
    100    if (pos != offset) {
    101        PR_fprintf(pr_stderr, "Seek for read on %s (to %d) failed\n",
    102                   libFile, offset);
    103        goto loser;
    104    }
    105    bytesRead = PR_Read(fd, &cbuf, 1);
    106    if (bytesRead != 1) {
    107        PR_fprintf(pr_stderr, "Read on %s (to %d) failed\n", libFile, offset);
    108        goto loser;
    109    }
    110 
    111    PR_fprintf(pr_stderr, "Changing byte 0x%08x (%d): from %02x (%d) to ",
    112               offset, offset, (unsigned char)cbuf, (unsigned char)cbuf);
    113    /* change it */
    114    cbuf ^= 1 << bitOffset;
    115    PR_fprintf(pr_stderr, "%02x (%d)\n",
    116               (unsigned char)cbuf, (unsigned char)cbuf);
    117 
    118    /* write it back out */
    119    pos = PR_Seek(fd, offset, PR_SEEK_SET);
    120    if (pos != offset) {
    121        PR_fprintf(pr_stderr, "Seek for write on %s (to %d) failed\n",
    122                   libFile, offset);
    123        goto loser;
    124    }
    125    bytesWritten = PR_Write(fd, &cbuf, 1);
    126    if (bytesWritten != 1) {
    127        PR_fprintf(pr_stderr, "Write on %s (to %d) failed\n", libFile, offset);
    128        goto loser;
    129    }
    130 
    131    retval = 0;
    132 
    133 loser:
    134    if (fd)
    135        PR_Close(fd);
    136    PR_Cleanup();
    137    return retval;
    138 }
    139 
    140 /*#DEFINES += -DSHLIB_SUFFIX=\"$(DLL_SUFFIX)\" -DSHLIB_PREFIX=\"$(DLL_PREFIX)\" */