| Message ID | 20220808032622.3804534-2-goldstein.w.n@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v1] elf: Replace `strcpy` call with `memcpy` [BZ #29454] | expand |
Hi, Le 08/08/2022 à 05:26, Noah Goldstein via Libc-alpha a écrit : > GCC normally does this optimization for us in > strlen_pass::handle_builtin_strcpy but only for optimized > build. To avoid needing to include strcpy.S in the rtld build to > support the debug build, just do the optimization by hand. It does fixes this build issue I had when using -Og (using gcc 11.2, on amd64): gcc -nostdlib -nostartfiles -shared -o .../build/elf/ld.so.new \ -Wl,-z,relro -Wl,-z,defs \ -Wl,-z,pack-relative-relocs \ .../build/elf/librtld.os -Wl,--version-script=.../build/ld.map \ -Wl,-soname=ld-linux-x86-64.so.2 /usr/bin/ld: .../build/elf/librtld.os: in function `_dl_load_cache_lookup': .../elf/dl-cache.c:513: undefined reference to `strcpy' collect2: error: ld returned 1 exit status make[2]: *** [Makefile:1347: .../build/elf/ld.so] Error 1 make[2]: Leaving directory '.../elf' make[1]: *** [Makefile:484: elf/subdir_lib] Error 2 make[1]: Leaving directory '...' make: *** [Makefile:9: all] Error 2 Thanks. > --- > elf/dl-cache.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/elf/dl-cache.c b/elf/dl-cache.c > index 8bbf110d02..b97c17b3a9 100644 > --- a/elf/dl-cache.c > +++ b/elf/dl-cache.c > @@ -509,8 +509,9 @@ _dl_load_cache_lookup (const char *name) > we are accessing. Therefore we must make the copy of the > mapping data without using malloc. */ > char *temp; > - temp = alloca (strlen (best) + 1); > - strcpy (temp, best); > + size_t best_len = strlen (best) + 1; > + temp = alloca (best_len); > + memcpy (temp, best, best_len); > return __strdup (temp); > } > Regards.
On Sun, Aug 7, 2022 at 8:26 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote: > > GCC normally does this optimization for us in > strlen_pass::handle_builtin_strcpy but only for optimized > build. To avoid needing to include strcpy.S in the rtld build to > support the debug build, just do the optimization by hand. > --- > elf/dl-cache.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/elf/dl-cache.c b/elf/dl-cache.c > index 8bbf110d02..b97c17b3a9 100644 > --- a/elf/dl-cache.c > +++ b/elf/dl-cache.c > @@ -509,8 +509,9 @@ _dl_load_cache_lookup (const char *name) > we are accessing. Therefore we must make the copy of the > mapping data without using malloc. */ > char *temp; > - temp = alloca (strlen (best) + 1); > - strcpy (temp, best); > + size_t best_len = strlen (best) + 1; > + temp = alloca (best_len); > + memcpy (temp, best, best_len); > return __strdup (temp); > } > > -- > 2.34.1 > LGTM. Thanks.
On Mon, Aug 8, 2022 at 10:24 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > On Sun, Aug 7, 2022 at 8:26 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote: > > > > GCC normally does this optimization for us in > > strlen_pass::handle_builtin_strcpy but only for optimized > > build. To avoid needing to include strcpy.S in the rtld build to > > support the debug build, just do the optimization by hand. > > --- > > elf/dl-cache.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/elf/dl-cache.c b/elf/dl-cache.c > > index 8bbf110d02..b97c17b3a9 100644 > > --- a/elf/dl-cache.c > > +++ b/elf/dl-cache.c > > @@ -509,8 +509,9 @@ _dl_load_cache_lookup (const char *name) > > we are accessing. Therefore we must make the copy of the > > mapping data without using malloc. */ > > char *temp; > > - temp = alloca (strlen (best) + 1); > > - strcpy (temp, best); > > + size_t best_len = strlen (best) + 1; > > + temp = alloca (best_len); > > + memcpy (temp, best, best_len); > > return __strdup (temp); > > } > > > > -- > > 2.34.1 > > > > LGTM. > > Thanks. > > -- > H.J. Any objections to backporting this to 2.36?
diff --git a/elf/dl-cache.c b/elf/dl-cache.c index 8bbf110d02..b97c17b3a9 100644 --- a/elf/dl-cache.c +++ b/elf/dl-cache.c @@ -509,8 +509,9 @@ _dl_load_cache_lookup (const char *name) we are accessing. Therefore we must make the copy of the mapping data without using malloc. */ char *temp; - temp = alloca (strlen (best) + 1); - strcpy (temp, best); + size_t best_len = strlen (best) + 1; + temp = alloca (best_len); + memcpy (temp, best, best_len); return __strdup (temp); }