diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/dl-osinfo.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/dl-osinfo.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/dl-osinfo.h b/sysdeps/unix/sysv/linux/dl-osinfo.h index dfb4cde72d..befa804cb1 100644 --- a/sysdeps/unix/sysv/linux/dl-osinfo.h +++ b/sysdeps/unix/sysv/linux/dl-osinfo.h @@ -43,6 +43,45 @@ dl_fatal (const char *str) static inline int __attribute__ ((always_inline)) _dl_discover_osversion (void) { +#if (defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO) && defined SHARED + if (GLRO(dl_sysinfo_map) != NULL) + { + /* If the kernel-supplied DSO contains a note indicating the kernel's + version, we don't need to call uname or parse any strings. */ + + static const struct + { + ElfW(Word) vendorlen; + ElfW(Word) datalen; + ElfW(Word) type; + char vendor[8]; + } expected_note = { sizeof "Linux", sizeof (ElfW(Word)), 0, "Linux" }; + const ElfW(Phdr) *const phdr = GLRO(dl_sysinfo_map)->l_phdr; + const ElfW(Word) phnum = GLRO(dl_sysinfo_map)->l_phnum; + for (uint_fast16_t i = 0; i < phnum; ++i) + if (phdr[i].p_type == PT_NOTE) + { + const ElfW(Addr) start = (phdr[i].p_vaddr + + GLRO(dl_sysinfo_map)->l_addr); + const struct + { + ElfW(Word) vendorlen; + ElfW(Word) datalen; + ElfW(Word) type; + } *note = (const void *) start; + while ((ElfW(Addr)) (note + 1) - start < phdr[i].p_memsz) + { + if (!memcmp (note, &expected_note, sizeof expected_note)) + return *(const ElfW(Word) *) ((const void *) note + + sizeof expected_note); +#define ROUND(len) (((len) + sizeof (ElfW(Word)) - 1) & -sizeof (ElfW(Word))) + note = ((const void *) (note + 1) + + ROUND (note->vendorlen) + ROUND (note->datalen)); + } + } + } +#endif + char bufmem[64]; char *buf = bufmem; unsigned int version; |