util/cbfstool/elfparsing.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #ifndef ELFPARSING_H
   4 #define ELFPARSING_H
   5
   6 #include "elf.h"
   7 #include "common.h"
   8
   9 struct parsed_elf {
  10         Elf64_Ehdr ehdr;
  11         Elf64_Phdr *phdr;
  12         Elf64_Shdr *shdr;
  13         /*
  14          * The relocs array contains pointers to arrays of relocation
  15          * structures.  Each index into the relocs array corresponds to its
  16          * corresponding section index. i.e. if a section i is of type SHT_REL
  17          * or SHT_RELA then the corresponding index into the relocs array will
  18          * contain the associated relocations. Otherwise thee entry will be
  19          * NULL.
  20          */
  21         Elf64_Rela **relocs;
  22         /*
  23          * Similarly to the relocs array the strtabs array consists of an
  24          * array of pointers where each entry represents a potential struct
  25          * buffer pointer. Only setions of type SHT_STRTAB will have a non-NULL
  26          * entry.
  27          */
  28         struct buffer **strtabs;
  29         /* Parsed symbols. */
  30         Elf64_Sym *syms;
  31 };
  32
  33 #define ELF_PARSE_PHDR          (1 << 0)
  34 #define ELF_PARSE_SHDR          (1 << 1)
  35 #define ELF_PARSE_RELOC         (1 << 2)
  36 #define ELF_PARSE_STRTAB        (1 << 3)
  37 #define ELF_PARSE_SYMTAB        (1 << 4)
  38
  39 #define ELF_PARSE_ALL           (-1)
  40
  41 /*
  42  * Parse an ELF file contained within provide struct buffer. The ELF header
  43  * is always parsed while the flags value containing the ELF_PARSE_* values
  44  * determine if other parts of the ELF file will be parsed as well.
  45  * Returns 0 on success, < 0 error.
  46  */
  47 int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags);
  48
  49 /*
  50  * Clean up memory associated with parsed_elf.
  51  */
  52 void parsed_elf_destroy(struct parsed_elf *pelf);
  53
  54
  55 int
  56 elf_headers(const struct buffer *pinput,
  57             Elf64_Ehdr *ehdr,
  58             Elf64_Phdr **pphdr,
  59             Elf64_Shdr **pshdr);
  60
  61 /* ELF writing support. */
  62 struct elf_writer;
  63
  64 /*
  65  * Initialize a 64-bit ELF header provided the inputs. While the structure
  66  * is a 64-bit header one can specify a 32-bit machine. The 64-bit version
  67  * is just used as a common structure. If one wants to specify the entry
  68  * point, for example, the caller can set it after filling in the common
  69  * bits. The machine, nbits, and endian values should be from the ELF
  70  * definitions (e.g. EM_386, ELFCLASS32, and ELFDATA2LSB) found in elf.h
  71  * with no endian conversion required.
  72  */
  73 void elf_init_eheader(Elf64_Ehdr *ehdr, int machine, int nbits, int endian);
  74
  75 /*
  76  * Initialize a new ELF writer. Default machine type, endianness, etc is
  77  * copied from the passed in Elf64_Ehdr. Returns NULL on failure, valid
  78  * pointer on success.
  79  */
  80 struct elf_writer *elf_writer_init(const Elf64_Ehdr *ehdr);
  81
  82 /*
  83  * Clean up any internal state represented by ew. Aftewards the elf_writer
  84  * is invalid.
  85  * It is safe to call elf_writer_destroy with ew as NULL. It returns without
  86  * performing any action.
  87  */
  88 void elf_writer_destroy(struct elf_writer *ew);
  89
  90 /*
  91  * Add a section to the ELF file. Section type, flags, and memsize are
  92  * maintained from the passed in Elf64_Shdr. The buffer represents the
  93  * content of the section while the name is the name of section itself.
  94  * Returns < 0 on error, 0 on success.
  95  */
  96 int elf_writer_add_section(struct elf_writer *ew, const Elf64_Shdr *shdr,
  97                            struct buffer *contents, const char *name);
  98
  99 /* Add an absolute symbol to the ELF file returning < 0 on error, index of
 100  * symbol otherwise. */
 101 int elf_writer_add_symbol(struct elf_writer *ew, const char *name,
 102                                 const char *section_name,
 103                                 Elf64_Addr value, Elf64_Word size,
 104                                 int binding, int type);
 105
 106 /* Add an absolute relocation referencing the provided symbol name. Returns < 0
 107  * on error, 0 on success. */
 108 int elf_writer_add_rel(struct elf_writer *ew, const char *sym, Elf64_Addr addr);
 109
 110 /*
 111  * Serialize the ELF file to the output buffer. Return < 0 on error,
 112  * 0 on success.
 113  */
 114 int elf_writer_serialize(struct elf_writer *ew, struct buffer *out);
 115
 116 /*
 117  * Calculate the loadable program's file size footprint and alignment requirements.
 118  * Returns < 0 on error, 0 on success.
 119  */
 120 int elf_program_file_size_align(const struct buffer *input, size_t *file_size, size_t *align);
 121
 122 #endif /* ELFPARSING_H */