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e47be608d5
dlopen() of a library that is already loaded fails. libelf_insert() rejects a name that is already in the module registry with EEXIST, and dlinsert() passes that straight out, so the second caller gets NULL. POSIX says dlopen() shall return a handle to the object, and there is no way today for two modules to hold the same library at once -- which is what a shared library is for. So dlopen() now takes another reference on a library that is already there, and dlclose() only tears it down when the last handle goes. The count lives in the dlfcn layer rather than in libelf_insert() so that insmod keeps its own behaviour: a second insmod of the same name still fails with EEXIST, which is right for a kernel module. The module name is what makes any of this possible, and a PROTECTED build did not have one. Names were defined for CONFIG_BUILD_FLAT or the kernel side of a split build, on the reasoning that only the kernel needed them, which predates dlopen() being usable from user space. Without a name the user-space copy of libelf cannot recognise a second open of a library, cannot count opens, and cannot make dlclose() mean anything -- two dlopen()s there produce two independent copies of the library and lose track of the first. Names are therefore defined wherever CONFIG_LIBC_DLFCN is, which costs NAME_MAX per loaded module in that configuration. The path no longer has to be copied either. The module name is the basename of the file and libelf_insert() takes it as a const string, so dlinsert() finds it with strrchr() instead of handing a writable duplicate of the whole path to basename(). BUILD_KERNEL is deliberately untouched. dlopen() returns NULL there unconditionally: dlinsert() is a stub, because sharing a library between processes with separate address spaces needs the text in a shared region and the data per process at a matching virtual address, which is a different problem from this one. Built for mps3-an547:picostest with and without CONFIG_LIBC_DLFCN, and for stm32f4discovery:kostest, a PROTECTED configuration, with it enabled. Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com> Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com> |
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| android | ||
| arpa | ||
| crypto | ||
| cxx | ||
| net | ||
| netinet | ||
| netpacket | ||
| nuttx | ||
| ssp | ||
| sys | ||
| .gitignore | ||
| aio.h | ||
| alloca.h | ||
| assert.h | ||
| byteswap.h | ||
| ctype.h | ||
| debug.h | ||
| dirent.h | ||
| dlfcn.h | ||
| dsp.h | ||
| dspb16.h | ||
| elf.h | ||
| elf32.h | ||
| elf64.h | ||
| endian.h | ||
| err.h | ||
| errno.h | ||
| execinfo.h | ||
| fcntl.h | ||
| fixedmath.h | ||
| fnmatch.h | ||
| ftw.h | ||
| gcov.h | ||
| getopt.h | ||
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| grp.h | ||
| hex2bin.h | ||
| iconv.h | ||
| ifaddrs.h | ||
| imx_container.h | ||
| inttypes.h | ||
| iso646.h | ||
| langinfo.h | ||
| libgen.h | ||
| libintl.h | ||
| limits.h | ||
| locale.h | ||
| lzf.h | ||
| malloc.h | ||
| mqueue.h | ||
| netdb.h | ||
| nl_types.h | ||
| nxflat.h | ||
| obstack.h | ||
| poll.h | ||
| pthread.h | ||
| pty.h | ||
| pwd.h | ||
| regex.h | ||
| resolv.h | ||
| sched.h | ||
| search.h | ||
| semaphore.h | ||
| shadow.h | ||
| signal.h | ||
| spawn.h | ||
| stdbool.h | ||
| stddef.h | ||
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| stdnoreturn.h | ||
| string.h | ||
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| syscall.h | ||
| syslog.h | ||
| termios.h | ||
| threads.h | ||
| time.h | ||
| ulimit.h | ||
| unistd.h | ||
| utime.h | ||
| uuid.h | ||
| wait.h | ||
| wchar.h | ||
| wctype.h | ||