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https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git
synced 2024-11-23 10:53:40 +08:00
libkmod: Use ELF offsets more often
Returned pointers are converted back to offsets in some functions. It is more readable to turn offsets into pointers though. Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org> Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> Link: https://github.com/kmod-project/kmod/pull/196 Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
This commit is contained in:
Tobias Stoeckmann
Lucas De Marchi
parent
2669abb18b
commit
25ab561bd5
@ -178,27 +178,31 @@ static inline const void *elf_get_mem(const struct kmod_elf *elf, uint64_t offse
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return elf->memory + offset;
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}
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static inline const void *elf_get_section_header(const struct kmod_elf *elf, uint16_t idx)
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/*
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* Returns offset to section header for section with given index or 0 on error
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* (offset 0 cannot be a valid section offset because ELF header is located there).
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*/
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static inline uint64_t elf_get_section_header_offset(const struct kmod_elf *elf,
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uint16_t idx)
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{
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assert(idx != SHN_UNDEF);
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assert(idx < elf->header.section.count);
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if (idx == SHN_UNDEF || idx >= elf->header.section.count) {
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ELFDBG(elf, "invalid section number: %" PRIu16 ", last=%" PRIu16 "\n",
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idx, elf->header.section.count);
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return NULL;
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return 0;
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}
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return elf_get_mem(elf, elf->header.section.offset +
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(uint64_t)(idx * elf->header.section.entry_size));
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return elf->header.section.offset +
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(uint64_t)(idx * elf->header.section.entry_size);
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}
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static inline int elf_get_section_info(const struct kmod_elf *elf, uint16_t idx,
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uint64_t *offset, uint64_t *size,
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uint32_t *nameoff)
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{
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const uint8_t *p = elf_get_section_header(elf, idx);
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uint64_t off = p - elf->memory;
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uint64_t off = elf_get_section_header_offset(elf, idx);
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if (p == NULL) {
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if (off == 0) {
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ELFDBG(elf, "no section at %" PRIu16 "\n", idx);
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goto fail;
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}
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@ -376,15 +380,16 @@ static int elf_find_section(const struct kmod_elf *elf, const char *section)
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return -ENODATA;
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}
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/* on success, sec_off and sec_size are range checked and valid */
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int kmod_elf_get_section(const struct kmod_elf *elf, const char *section,
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const void **buf, uint64_t *buf_size)
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uint64_t *sec_off, uint64_t *sec_size)
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{
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uint64_t nameslen;
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const char *names = elf_get_strings_section(elf, &nameslen);
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uint16_t i;
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*buf = NULL;
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*buf_size = 0;
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*sec_off = 0;
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*sec_size = 0;
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for (i = 1; i < elf->header.section.count; i++) {
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uint64_t off, size;
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@ -399,8 +404,8 @@ int kmod_elf_get_section(const struct kmod_elf *elf, const char *section,
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if (!streq(section, n))
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continue;
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*buf = elf_get_mem(elf, off);
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*buf_size = size;
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*sec_off = off;
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*sec_size = size;
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return 0;
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}
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@ -412,21 +417,20 @@ int kmod_elf_get_strings(const struct kmod_elf *elf, const char *section, char *
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{
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size_t i, j, count;
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size_t tmp_size, vec_size, total_size;
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uint64_t size;
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const void *buf;
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uint64_t off, size;
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const char *strings;
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char *s, **a;
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int err;
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*array = NULL;
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err = kmod_elf_get_section(elf, section, &buf, &size);
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err = kmod_elf_get_section(elf, section, &off, &size);
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if (err < 0)
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return err;
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strings = buf;
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if (strings == NULL || size == 0)
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if (size == 0)
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return 0;
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strings = elf_get_mem(elf, off);
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/* skip zero padding */
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while (strings[0] == '\0' && size > 1) {
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@ -492,9 +496,8 @@ int kmod_elf_get_strings(const struct kmod_elf *elf, const char *section, char *
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int kmod_elf_get_modversions(const struct kmod_elf *elf, struct kmod_modversion **array)
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{
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size_t off, offcrc, slen;
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uint64_t size;
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uint64_t sec_off, size;
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struct kmod_modversion *a;
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const void *buf;
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char *itr;
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int i, count, err;
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#define MODVERSION_SEC_SIZE (sizeof(struct kmod_modversion64))
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@ -508,11 +511,11 @@ int kmod_elf_get_modversions(const struct kmod_elf *elf, struct kmod_modversion
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*array = NULL;
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err = kmod_elf_get_section(elf, "__versions", &buf, &size);
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err = kmod_elf_get_section(elf, "__versions", &sec_off, &size);
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if (err < 0)
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return err;
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if (buf == NULL || size == 0)
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if (size == 0)
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return 0;
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if (size % MODVERSION_SEC_SIZE != 0)
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@ -520,7 +523,7 @@ int kmod_elf_get_modversions(const struct kmod_elf *elf, struct kmod_modversion
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count = size / MODVERSION_SEC_SIZE;
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off = (const uint8_t *)buf - elf->memory;
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off = sec_off;
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slen = 0;
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for (i = 0; i < count; i++, off += MODVERSION_SEC_SIZE) {
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@ -537,7 +540,7 @@ int kmod_elf_get_modversions(const struct kmod_elf *elf, struct kmod_modversion
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return -errno;
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itr = (char *)(a + count);
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off = (const uint8_t *)buf - elf->memory;
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off = sec_off;
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for (i = 0; i < count; i++, off += MODVERSION_SEC_SIZE) {
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uint64_t crc = elf_get_uint(elf, off, offcrc);
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@ -568,8 +571,7 @@ static int elf_strip_versions_section(const struct kmod_elf *elf, uint8_t *chang
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if (idx < 0)
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return idx == -ENODATA ? 0 : idx;
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buf = elf_get_section_header(elf, idx);
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off = (const uint8_t *)buf - elf->memory;
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off = elf_get_section_header_offset(elf, idx);
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if (elf->x32) {
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off += offsetof(Elf32_Shdr, sh_flags);
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@ -587,17 +589,16 @@ static int elf_strip_versions_section(const struct kmod_elf *elf, uint8_t *chang
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static int elf_strip_vermagic(const struct kmod_elf *elf, uint8_t *changed)
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{
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uint64_t i, size;
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const void *buf;
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uint64_t i, sec_off, size;
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const char *strings;
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int err;
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err = kmod_elf_get_section(elf, ".modinfo", &buf, &size);
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err = kmod_elf_get_section(elf, ".modinfo", &sec_off, &size);
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if (err < 0)
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return err == -ENODATA ? 0 : err;
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strings = buf;
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if (strings == NULL || size == 0)
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if (size == 0)
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return 0;
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strings = elf_get_mem(elf, sec_off);
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/* skip zero padding */
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while (strings[0] == '\0' && size > 1) {
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@ -674,8 +675,7 @@ fail:
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static int kmod_elf_get_symbols_symtab(const struct kmod_elf *elf,
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struct kmod_modversion **array)
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{
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uint64_t i, last, size;
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const void *buf;
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uint64_t i, last, off, size;
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const char *strings;
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char *itr;
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struct kmod_modversion *a;
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@ -683,12 +683,12 @@ static int kmod_elf_get_symbols_symtab(const struct kmod_elf *elf,
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*array = NULL;
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err = kmod_elf_get_section(elf, "__ksymtab_strings", &buf, &size);
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err = kmod_elf_get_section(elf, "__ksymtab_strings", &off, &size);
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if (err < 0)
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return err;
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strings = buf;
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if (strings == NULL || size == 0)
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if (size == 0)
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return 0;
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strings = elf_get_mem(elf, off);
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/* skip zero padding */
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while (strings[0] == '\0' && size > 1) {
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@ -795,20 +795,19 @@ int kmod_elf_get_symbols(const struct kmod_elf *elf, struct kmod_modversion **ar
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{
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static const char crc_str[] = "__crc_";
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static const size_t crc_strlen = sizeof(crc_str) - 1;
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uint64_t strtablen, symtablen, str_off, sym_off;
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const void *strtab, *symtab;
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uint64_t strtablen, symtablen, str_sec_off, sym_sec_off, str_off, sym_off;
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struct kmod_modversion *a;
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char *itr;
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size_t i, count, symcount, slen, symlen;
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int err;
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err = kmod_elf_get_section(elf, ".strtab", &strtab, &strtablen);
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err = kmod_elf_get_section(elf, ".strtab", &str_sec_off, &strtablen);
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if (err < 0) {
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ELFDBG(elf, "no .strtab found.\n");
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goto fallback;
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}
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err = kmod_elf_get_section(elf, ".symtab", &symtab, &symtablen);
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err = kmod_elf_get_section(elf, ".symtab", &sym_sec_off, &symtablen);
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if (err < 0) {
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ELFDBG(elf, "no .symtab found.\n");
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goto fallback;
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@ -830,8 +829,8 @@ int kmod_elf_get_symbols(const struct kmod_elf *elf, struct kmod_modversion **ar
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symcount = symtablen / symlen;
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count = 0;
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slen = 0;
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str_off = (const uint8_t *)strtab - elf->memory;
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sym_off = (const uint8_t *)symtab - elf->memory + symlen;
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str_off = str_sec_off;
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sym_off = sym_sec_off;
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for (i = 1; i < symcount; i++, sym_off += symlen) {
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const char *name;
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uint32_t name_off;
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@ -871,8 +870,8 @@ int kmod_elf_get_symbols(const struct kmod_elf *elf, struct kmod_modversion **ar
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itr = (char *)(a + count);
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count = 0;
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str_off = (const uint8_t *)strtab - elf->memory;
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sym_off = (const uint8_t *)symtab - elf->memory + symlen;
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str_off = str_sec_off;
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sym_off = sym_sec_off;
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for (i = 1; i < symcount; i++, sym_off += symlen) {
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const char *name;
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uint32_t name_off;
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@ -922,10 +921,10 @@ fallback:
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return kmod_elf_get_symbols_symtab(elf, array);
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}
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static int kmod_elf_crc_find(const struct kmod_elf *elf, const void *versions,
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static int kmod_elf_crc_find(const struct kmod_elf *elf, uint64_t off,
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uint64_t versionslen, const char *name, uint64_t *crc)
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{
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size_t verlen, crclen, off;
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size_t verlen, crclen;
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uint64_t i;
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if (elf->x32) {
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@ -938,7 +937,6 @@ static int kmod_elf_crc_find(const struct kmod_elf *elf, const void *versions,
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crclen = sizeof(mv->crc);
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}
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off = (const uint8_t *)versions - elf->memory;
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for (i = 0; i < versionslen; i += verlen) {
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const char *symbol = elf_get_mem(elf, off + i + crclen);
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if (!streq(name, symbol))
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@ -962,7 +960,7 @@ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf,
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struct kmod_modversion **array)
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{
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uint64_t versionslen, strtablen, symtablen, str_off, sym_off, ver_off;
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const void *versions, *strtab, *symtab;
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uint64_t str_sec_off, sym_sec_off;
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struct kmod_modversion *a;
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char *itr;
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size_t slen, verlen, symlen, crclen;
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@ -971,9 +969,8 @@ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf,
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uint8_t *visited_versions;
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uint64_t *symcrcs;
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err = kmod_elf_get_section(elf, "__versions", &versions, &versionslen);
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err = kmod_elf_get_section(elf, "__versions", &ver_off, &versionslen);
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if (err < 0) {
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versions = NULL;
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versionslen = 0;
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verlen = 0;
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crclen = 0;
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@ -992,18 +989,18 @@ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf,
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"unexpected __versions of length %" PRIu64
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", not multiple of %zd as expected.\n",
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versionslen, verlen);
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versions = NULL;
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ver_off = 0;
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versionslen = 0;
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}
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}
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err = kmod_elf_get_section(elf, ".strtab", &strtab, &strtablen);
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err = kmod_elf_get_section(elf, ".strtab", &str_sec_off, &strtablen);
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if (err < 0) {
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ELFDBG(elf, "no .strtab found.\n");
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return -EINVAL;
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}
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err = kmod_elf_get_section(elf, ".symtab", &symtab, &symtablen);
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err = kmod_elf_get_section(elf, ".symtab", &sym_sec_off, &symtablen);
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if (err < 0) {
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ELFDBG(elf, "no .symtab found.\n");
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return -EINVAL;
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@ -1038,8 +1035,8 @@ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf,
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symcount = symtablen / symlen;
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count = 0;
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slen = 0;
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str_off = (const uint8_t *)strtab - elf->memory;
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sym_off = (const uint8_t *)symtab - elf->memory + symlen;
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str_off = str_sec_off;
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sym_off = sym_sec_off + symlen;
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symcrcs = calloc(symcount, sizeof(uint64_t));
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if (symcrcs == NULL) {
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@ -1108,7 +1105,7 @@ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf,
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slen += strlen(name) + 1;
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count++;
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idx = kmod_elf_crc_find(elf, versions, versionslen, name, &crc);
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idx = kmod_elf_crc_find(elf, ver_off, versionslen, name, &crc);
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if (idx >= 0 && visited_versions != NULL)
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visited_versions[idx] = 1;
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symcrcs[i] = crc;
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@ -1116,7 +1113,6 @@ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf,
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if (visited_versions != NULL) {
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/* module_layout/struct_module are not visited, but needed */
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ver_off = (const uint8_t *)versions - elf->memory;
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for (i = 0; i < vercount; i++) {
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if (visited_versions[i] == 0) {
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const char *name;
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@ -1144,8 +1140,8 @@ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf,
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itr = (char *)(a + count);
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count = 0;
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str_off = (const uint8_t *)strtab - elf->memory;
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sym_off = (const uint8_t *)symtab - elf->memory + symlen;
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str_off = str_sec_off;
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sym_off = sym_sec_off + symlen;
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for (i = 1; i < symcount; i++, sym_off += symlen) {
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const char *name;
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uint64_t crc;
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@ -1220,7 +1216,6 @@ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf,
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return count;
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/* add unvisited (module_layout/struct_module) */
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ver_off = (const uint8_t *)versions - elf->memory;
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for (i = 0; i < vercount; i++) {
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const char *name;
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uint64_t crc;
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@ -161,7 +161,7 @@ _must_check_ _nonnull_all_ const void *kmod_elf_strip(const struct kmod_elf *elf
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* Debug mock lib need to find section ".gnu.linkonce.this_module" in order to
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* get modname
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*/
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_must_check_ _nonnull_all_ int kmod_elf_get_section(const struct kmod_elf *elf, const char *section, const void **buf, uint64_t *buf_size);
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_must_check_ _nonnull_all_ int kmod_elf_get_section(const struct kmod_elf *elf, const char *section, uint64_t *sec_off, uint64_t *sec_size);
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/* libkmod-signature.c */
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struct kmod_signature_info {
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@ -226,6 +226,7 @@ long init_module(void *mem, unsigned long len, const char *args)
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struct kmod_elf *elf;
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struct mod *mod;
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const void *buf;
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uint64_t off;
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uint64_t bufsize;
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int err;
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uint8_t class;
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@ -237,7 +238,8 @@ long init_module(void *mem, unsigned long len, const char *args)
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if (elf == NULL)
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return 0;
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err = kmod_elf_get_section(elf, ".gnu.linkonce.this_module", &buf, &bufsize);
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err = kmod_elf_get_section(elf, ".gnu.linkonce.this_module", &off, &bufsize);
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buf = (const char *)kmod_elf_get_memory(elf) + off;
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kmod_elf_unref(elf);
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/* We couldn't parse the ELF file. Just exit as if it was successful */
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