modules/apm.c

   1 // This file is part of Deark.
   2 // Copyright (C) 2019 Jason Summers
   3 // See the file COPYING for terms of use.
   4
   5 // Apple Partition Map
   6
   7 #include <deark-config.h>
   8 #include <deark-private.h>
   9 DE_DECLARE_MODULE(de_module_apm);
  10
  11 struct partition_info {
  12         i64 partition_startsec;
  13         i64 partition_startpos;
  14         i64 partition_size_in_secs;
  15         i64 partition_size_in_bytes;
  16         unsigned int partition_status;
  17         de_ucstring *pname;
  18         struct de_stringreaderdata *ptype;
  19 };
  20
  21 typedef struct localctx_struct {
  22         i64 secsize;
  23         i64 npartitions;
  24 } lctx;
  25
  26 static void destroy_partition_info(deark *c, struct partition_info *pi)
  27 {
  28         if(!pi) return;
  29         ucstring_destroy(pi->pname);
  30         de_destroy_stringreaderdata(c, pi->ptype);
  31         de_free(c, pi);
  32 }
  33
  34 static void do_extract_partition(deark *c, lctx *d, struct partition_info *pi)
  35 {
  36         de_finfo *fi = NULL;
  37         const char *ext = "partition";
  38         i64 len_to_extract;
  39         int use_pname_in_name = 1;
  40         int use_ptype_in_name = 1;
  41         de_ucstring *outfname = NULL;
  42
  43         if(pi->partition_startpos >= c->infile->len) goto done;
  44         len_to_extract = pi->partition_size_in_bytes;
  45         if(pi->partition_startpos + len_to_extract > c->infile->len) {
  46                 de_warn(c, "Partition at %"I64_FMT" goes beyond end of file", pi->partition_startpos);
  47                 len_to_extract = c->infile->len - pi->partition_startpos;
  48         }
  49
  50         fi = de_finfo_create(c);
  51         outfname = ucstring_create(c);
  52
  53         if(!de_strcmp(pi->ptype->sz, "Apple_partition_map")) {
  54                 ext = "bin";
  55                 use_pname_in_name = 0;
  56         }
  57         else if(!de_strcmp(pi->ptype->sz, "Apple_HFS")) {
  58                 unsigned int sig = (unsigned int)de_getu16be(pi->partition_startpos+1024);
  59                 if(sig==0x4244) { // "BD"
  60                         ext = "hfs";
  61                         use_ptype_in_name = 0;
  62                 }
  63                 else if(sig==0x482b) { // "H+"
  64                         ext="hfs+.hfs";
  65                         use_ptype_in_name = 0;
  66                 }
  67                 else if(sig==0x4858) { // "HX"
  68                         ext="hfsx.hfs";
  69                         use_ptype_in_name = 0;
  70                 }
  71         }
  72
  73         if(use_pname_in_name && ucstring_isnonempty(pi->pname)) {
  74                 ucstring_append_ucstring(outfname, pi->pname);
  75         }
  76         if(use_ptype_in_name && ucstring_isnonempty(pi->ptype->str)) {
  77                 if(outfname->len>1) {
  78                         ucstring_append_sz(outfname, ".", DE_ENCODING_LATIN1);
  79                 }
  80                 ucstring_append_ucstring(outfname, pi->ptype->str);
  81         }
  82         if(outfname->len>1) {
  83                 de_finfo_set_name_from_ucstring(c, fi, outfname, 0);
  84         }
  85
  86         dbuf_create_file_from_slice(c->infile, pi->partition_startpos,
  87                 len_to_extract, ext, fi, 0);
  88
  89 done:
  90         de_finfo_destroy(c, fi);
  91         ucstring_destroy(outfname);
  92 }
  93
  94 static int do_entry_at_sector(deark *c, lctx *d, i64 secnum)
  95 {
  96         i64 pos = secnum*d->secsize;
  97         i64 npartitions;
  98         int retval = 0;
  99         int saved_indent_level;
 100         struct partition_info *pi = NULL;
 101
 102         de_dbg_indent_save(c, &saved_indent_level);
 103
 104         if(dbuf_memcmp(c->infile, pos, "PM", 2)) {
 105                 de_err(c, "Partition map entry not found at %"I64_FMT, pos);
 106                 goto done;
 107         }
 108
 109         pi = de_malloc(c, sizeof(struct partition_info));
 110
 111         de_dbg(c, "partition map entry at %"I64_FMT, pos);
 112         de_dbg_indent(c, 1);
 113         pos += 4;
 114
 115         npartitions = de_getu32be_p(&pos);
 116         de_dbg(c, "total number of partitions: %d", (int)npartitions);
 117         if(secnum==1) {
 118                 d->npartitions = npartitions;
 119         }
 120         retval = 1;
 121
 122         pi->partition_startsec = de_getu32be_p(&pos);
 123         pi->partition_startpos = pi->partition_startsec * d->secsize;
 124         de_dbg(c, "starting sector of partition: %"I64_FMT" (offset %"I64_FMT")",
 125                 pi->partition_startsec, pi->partition_startpos);
 126
 127         pi->partition_size_in_secs = de_getu32be_p(&pos);
 128         pi->partition_size_in_bytes = pi->partition_size_in_secs * d->secsize;
 129         de_dbg(c, "partition size: %"I64_FMT" sectors (%"I64_FMT" bytes)",
 130                 pi->partition_size_in_secs, pi->partition_size_in_bytes);
 131
 132         pi->pname = ucstring_create(c);
 133         dbuf_read_to_ucstring(c->infile, pos, 32, pi->pname, DE_CONVFLAG_STOP_AT_NUL,
 134                 DE_ENCODING_ASCII);
 135         de_dbg(c, "partition name: \"%s\"", ucstring_getpsz(pi->pname));
 136         pos += 32;
 137
 138         pi->ptype = dbuf_read_string(c->infile, pos, 32, 32, DE_CONVFLAG_STOP_AT_NUL,
 139                 DE_ENCODING_ASCII);
 140         de_dbg(c, "partition type: \"%s\"", ucstring_getpsz(pi->ptype->str));
 141         pos += 32;
 142
 143         pi->partition_status = (unsigned int)de_getu32be_p(&pos);
 144         de_dbg(c, "status: 0x%08x", (unsigned int)pi->partition_status);
 145
 146         // TODO: More fields here
 147
 148         do_extract_partition(c, d, pi);
 149
 150 done:
 151         if(pi) destroy_partition_info(c, pi);
 152         de_dbg_indent_restore(c, saved_indent_level);
 153         return retval;
 154 }
 155
 156 static void de_run_apm(deark *c, de_module_params *mparams)
 157 {
 158         lctx *d = NULL;
 159         i64 i;
 160         int ret;
 161
 162         d = de_malloc(c, sizeof(lctx));
 163
 164         d->secsize = 512;
 165
 166         // Read the first map entry (should set d->npartitions)
 167         ret = do_entry_at_sector(c, d, 1);
 168         if(!ret) goto done;
 169
 170         // Read the rest of the entries
 171         for(i=1; i<d->npartitions; i++) {
 172                 ret = do_entry_at_sector(c, d, 1+i);
 173                 if(!ret) goto done;
 174         }
 175
 176 done:
 177         de_free(c, d);
 178 }
 179
 180 static int de_identify_apm(deark *c)
 181 {
 182         i64 i;
 183
 184         for(i=0; i<2; i++) {
 185                 if(dbuf_memcmp(c->infile, 512+i*512, "PM\x00\x00", 4))
 186                         return 0;
 187         }
 188         return 75;
 189 }
 190
 191 void de_module_apm(deark *c, struct deark_module_info *mi)
 192 {
 193         mi->id = "apm";
 194         mi->desc = "Apple Partition Map";
 195         mi->run_fn = de_run_apm;
 196         mi->identify_fn = de_identify_apm;
 197 }