utils/readsoname2.c

   1 static char *readsonameXX(char *name, FILE *infile, int expected_type, int *type)
   2 {
   3         ElfW(Ehdr) *epnt;
   4         ElfW(Phdr) *ppnt;
   5         unsigned int i, j;
   6         char *header;
   7         ElfW(Addr) dynamic_addr = 0;
   8         ElfW(Addr) dynamic_size = 0;
   9         unsigned long page_size = getpagesize();
  10         ElfW(Addr) strtab_val = 0;
  11         ElfW(Addr) needed_val;
  12         ElfW(Addr) loadaddr = -1;
  13         ElfW(Dyn) *dpnt;
  14         struct stat st;
  15         char *needed;
  16         char *soname = NULL;
  17         int multi_libcs = 0;
  18
  19         if (expected_type == LIB_DLL) {
  20                 warn("%s does not match type specified for directory!", name);
  21                 expected_type = LIB_ANY;
  22         }
  23
  24         *type = LIB_ELF;
  25
  26         if (fstat(fileno(infile), &st))
  27                 return NULL;
  28         header =
  29             mmap(0, st.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
  30                  fileno(infile), 0);
  31         if (header == (caddr_t) - 1)
  32                 return NULL;
  33
  34         epnt = (ElfW(Ehdr) *) header;
  35         if ((char *)(epnt + 1) > (char *)(header + st.st_size))
  36                 goto skip;
  37
  38         if (UCLIBC_ENDIAN_HOST == UCLIBC_ENDIAN_LITTLE)
  39                 byteswap = (epnt->e_ident[5] == ELFDATA2MSB) ? 1 : 0;
  40         else if (UCLIBC_ENDIAN_HOST == UCLIBC_ENDIAN_BIG)
  41                 byteswap = (epnt->e_ident[5] == ELFDATA2LSB) ? 1 : 0;
  42
  43         /* Be very lazy, and only byteswap the stuff we use */
  44         if (byteswap == 1) {
  45                 epnt->e_phoff = bswap_32(epnt->e_phoff);
  46                 epnt->e_phnum = bswap_16(epnt->e_phnum);
  47         }
  48
  49         ppnt = (ElfW(Phdr) *) & header[epnt->e_phoff];
  50         if ((char *)ppnt < (char *)header ||
  51             (char *)(ppnt + epnt->e_phnum) > (char *)(header + st.st_size))
  52                 goto skip;
  53
  54         for (i = 0; i < epnt->e_phnum; i++) {
  55                 /* Be very lazy, and only byteswap the stuff we use */
  56                 if (byteswap == 1) {
  57                         ppnt->p_type = bswap_32(ppnt->p_type);
  58                         ppnt->p_vaddr = bswap_32(ppnt->p_vaddr);
  59                         ppnt->p_offset = bswap_32(ppnt->p_offset);
  60                         ppnt->p_filesz = bswap_32(ppnt->p_filesz);
  61                 }
  62
  63                 if (loadaddr == (ElfW(Addr)) - 1 && ppnt->p_type == PT_LOAD)
  64                         loadaddr = (ppnt->p_vaddr & ~(page_size - 1)) -
  65                             (ppnt->p_offset & ~(page_size - 1));
  66                 if (ppnt->p_type == 2) {
  67                         dynamic_addr = ppnt->p_offset;
  68                         dynamic_size = ppnt->p_filesz;
  69                 };
  70                 ppnt++;
  71         };
  72
  73         dpnt = (ElfW(Dyn) *) & header[dynamic_addr];
  74         dynamic_size = dynamic_size / sizeof(ElfW(Dyn));
  75         if ((char *)dpnt < (char *)header ||
  76             (char *)(dpnt + dynamic_size) > (char *)(header + st.st_size))
  77                 goto skip;
  78
  79         if (byteswap == 1) {
  80                 dpnt->d_tag = bswap_32(dpnt->d_tag);
  81                 dpnt->d_un.d_val = bswap_32(dpnt->d_un.d_val);
  82         }
  83
  84         while (dpnt->d_tag != DT_NULL) {
  85                 if (dpnt->d_tag == DT_STRTAB)
  86                         strtab_val = dpnt->d_un.d_val;
  87                 dpnt++;
  88                 if (byteswap == 1) {
  89                         dpnt->d_tag = bswap_32(dpnt->d_tag);
  90                         dpnt->d_un.d_val = bswap_32(dpnt->d_un.d_val);
  91                 }
  92         };
  93
  94         if (!strtab_val)
  95                 goto skip;
  96
  97         dpnt = (ElfW(Dyn) *) & header[dynamic_addr];
  98         while (dpnt->d_tag != DT_NULL) {
  99                 if (dpnt->d_tag == DT_SONAME || dpnt->d_tag == DT_NEEDED) {
 100                         needed_val = dpnt->d_un.d_val;
 101                         if (needed_val + strtab_val >= loadaddr ||
 102                             needed_val + strtab_val < st.st_size - loadaddr) {
 103                                 needed =
 104                                     (char *)(header - loadaddr + strtab_val +
 105                                              needed_val);
 106
 107                                 if (dpnt->d_tag == DT_SONAME)
 108                                         soname = xstrdup(needed);
 109
 110                                 for (j = 0; needed_tab[j].soname != NULL; j++) {
 111                                         if (strcmp(needed, needed_tab[j].soname)
 112                                             == 0) {
 113                                                 if (*type != LIB_ELF
 114                                                     && *type !=
 115                                                     needed_tab[j].type)
 116                                                         multi_libcs = 1;
 117                                                 *type = needed_tab[j].type;
 118                                         }
 119                                 }
 120                         }
 121                 }
 122                 dpnt++;
 123         };
 124
 125         if (multi_libcs)
 126                 warn("%s appears to be for multiple libc's", name);
 127
 128         /* If we could not deduce the libc type, and we know what to expect, set the type */
 129         if (*type == LIB_ELF && expected_type != LIB_ANY)
 130                 *type = expected_type;
 131
 132         if (expected_type != LIB_ANY && expected_type != LIB_ELF &&
 133             expected_type != *type) {
 134                 warn("%s does not match type specified for directory!", name);
 135         }
 136
 137       skip:
 138         munmap(header, st.st_size);
 139
 140         return soname;
 141 }