diff options
| -rw-r--r-- | ChangeLog | 14 | ||||
| -rw-r--r-- | config.make.in | 1 | ||||
| -rw-r--r-- | elf/Makefile | 6 | ||||
| -rw-r--r-- | elf/dl-tunables.c | 129 | ||||
| -rw-r--r-- | malloc/Makefile | 6 | ||||
| -rw-r--r-- | malloc/tst-malloc-usable-static-tunables.c | 1 | ||||
| -rw-r--r-- | malloc/tst-malloc-usable-tunables.c | 1 |
7 files changed, 156 insertions, 2 deletions
@@ -1,5 +1,19 @@ 2016-12-31 Siddhesh Poyarekar <siddhesh@sourceware.org> + * config.make.in (have-loop-to-function): Define. + * elf/Makefile (CFLAGS-dl-tunables.c): Add + -fno-tree-loop-distribute-patterns. + * elf/dl-tunables.c: Include libc-internals.h. + (GLIBC_TUNABLES): New macro. + (tunables_strdup): New function. + (parse_tunables): New function. + (min_strlen): New function. + (__tunables_init): Use the new functions and macro. + (disable_tunable): Disable tunable from GLIBC_TUNABLES. + * malloc/tst-malloc-usable-tunables.c: New test case. + * malloc/tst-malloc-usable-static-tunables.c: New test case. + * malloc/Makefile (tests, tests-static): Add tests. + * manual/install.texi: Add --enable-tunables option. * INSTALL: Regenerate. * README.tunables: New file. diff --git a/config.make.in b/config.make.in index 2f8dae2..5836b32 100644 --- a/config.make.in +++ b/config.make.in @@ -71,6 +71,7 @@ have-hash-style = @libc_cv_hashstyle@ use-default-link = @use_default_link@ output-format = @libc_cv_output_format@ have-cxx-thread_local = @libc_cv_cxx_thread_local@ +have-loop-to-function = @libc_cv_cc_loop_to_function@ multi-arch = @multi_arch@ diff --git a/elf/Makefile b/elf/Makefile index de28d99..3cda2c9 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -38,6 +38,12 @@ endif ifeq (yes,$(have-tunables)) dl-routines += dl-tunables + +# Make sure that the compiler does not insert any library calls in tunables +# code paths. +ifeq (yes,$(have-loop-to-function)) +CFLAGS-dl-tunables.c = -fno-tree-loop-distribute-patterns +endif endif all-dl-routines = $(dl-routines) $(sysdep-dl-routines) diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c index 472747b..8d69140 100644 --- a/elf/dl-tunables.c +++ b/elf/dl-tunables.c @@ -30,7 +30,10 @@ #define TUNABLES_INTERNAL 1 #include "dl-tunables.h" -/* Compare environment names, bounded by the name hardcoded in glibc. */ +#define GLIBC_TUNABLES "GLIBC_TUNABLES" + +/* Compare environment or tunable names, bounded by the name hardcoded in + glibc. */ static bool is_name (const char *orig, const char *envname) { @@ -45,6 +48,29 @@ is_name (const char *orig, const char *envname) return false; } +static char * +tunables_strdup (const char *in) +{ + size_t i = 0; + + while (in[i++] != '\0'); + char *out = __sbrk (i); + + /* FIXME: In reality if the allocation fails, __sbrk will crash attempting to + set the thread-local errno since the TCB has not yet been set up. This + needs to be fixed with an __sbrk implementation that does not set + errno. */ + if (out == (void *)-1) + return NULL; + + i--; + + while (i-- > 0) + out[i] = in[i]; + + return out; +} + static char ** get_next_env (char **envp, char **name, size_t *namelen, char **val) { @@ -218,6 +244,82 @@ tunable_initialize (tunable_t *cur, const char *strval) } } +static void +parse_tunables (char *tunestr) +{ + if (tunestr == NULL || *tunestr == '\0') + return; + + char *p = tunestr; + + while (true) + { + char *name = p; + size_t len = 0; + + /* First, find where the name ends. */ + while (p[len] != '=' && p[len] != ':' && p[len] != '\0') + len++; + + /* If we reach the end of the string before getting a valid name-value + pair, bail out. */ + if (p[len] == '\0') + return; + + /* We did not find a valid name-value pair before encountering the + colon. */ + if (p[len]== ':') + { + p += len + 1; + continue; + } + + p += len + 1; + + char *value = p; + len = 0; + + while (p[len] != ':' && p[len] != '\0') + len++; + + char end = p[len]; + p[len] = '\0'; + + /* Add the tunable if it exists. */ + for (size_t i = 0; i < sizeof (tunable_list) / sizeof (tunable_t); i++) + { + tunable_t *cur = &tunable_list[i]; + + /* If we are in a secure context (AT_SECURE) then ignore the tunable + unless it is explicitly marked as secure. Tunable values take + precendence over their envvar aliases. */ + if (__libc_enable_secure && !cur->is_secure) + continue; + + if (is_name (cur->name, name)) + { + tunable_initialize (cur, value); + break; + } + } + + if (end == ':') + p += len + 1; + else + return; + } +} + +static size_t +min_strlen (const char *s) +{ + size_t i = 0; + while (*s++ != '\0') + i++; + + return i; +} + /* Disable a tunable if it is set. */ static void disable_tunable (tunable_id_t id, char **envp) @@ -226,6 +328,23 @@ disable_tunable (tunable_id_t id, char **envp) if (env_alias != NULL) tunables_unsetenv (envp, tunable_list[id].env_alias); + + char *tunable = getenv (GLIBC_TUNABLES); + const char *cmp = tunable_list[id].name; + const size_t len = min_strlen (cmp); + + while (tunable && *tunable != '\0' && *tunable != ':') + { + if (is_name (tunable, cmp)) + { + tunable += len; + /* Overwrite the = and the value with colons. */ + while (*tunable != '\0' && *tunable != ':') + *tunable++ = ':'; + break; + } + tunable++; + } } /* Disable the glibc.malloc.check tunable in SETUID/SETGID programs unless @@ -256,6 +375,14 @@ __tunables_init (char **envp) while ((envp = get_next_env (envp, &envname, &len, &envval)) != NULL) { + if (is_name (GLIBC_TUNABLES, envname)) + { + char *val = tunables_strdup (envval); + if (val != NULL) + parse_tunables (val); + continue; + } + for (int i = 0; i < sizeof (tunable_list) / sizeof (tunable_t); i++) { tunable_t *cur = &tunable_list[i]; diff --git a/malloc/Makefile b/malloc/Makefile index 4e4104e..a34e20c 100644 --- a/malloc/Makefile +++ b/malloc/Makefile @@ -33,11 +33,13 @@ tests := mallocbug tst-malloc tst-valloc tst-calloc tst-obstack \ tst-mallocfork2 \ tst-interpose-nothread \ tst-interpose-thread \ + tst-malloc-usable-tunables tests-static := \ tst-interpose-static-nothread \ tst-interpose-static-thread \ - tst-malloc-usable-static + tst-malloc-usable-static \ + tst-malloc-usable-static-tunables tests += $(tests-static) test-srcs = tst-mtrace @@ -160,6 +162,8 @@ endif tst-mcheck-ENV = MALLOC_CHECK_=3 tst-malloc-usable-ENV = MALLOC_CHECK_=3 tst-malloc-usable-static-ENV = $(tst-malloc-usable-ENV) +tst-malloc-usable-tunables-ENV = GLIBC_TUNABLES=glibc.malloc.check=3 +tst-malloc-usable-static-tunables-ENV = $(tst-malloc-usable-tunables-ENV) # Uncomment this for test releases. For public releases it is too expensive. #CPPFLAGS-malloc.o += -DMALLOC_DEBUG=1 diff --git a/malloc/tst-malloc-usable-static-tunables.c b/malloc/tst-malloc-usable-static-tunables.c new file mode 100644 index 0000000..8907db0 --- /dev/null +++ b/malloc/tst-malloc-usable-static-tunables.c @@ -0,0 +1 @@ +#include <malloc/tst-malloc-usable.c> diff --git a/malloc/tst-malloc-usable-tunables.c b/malloc/tst-malloc-usable-tunables.c new file mode 100644 index 0000000..8907db0 --- /dev/null +++ b/malloc/tst-malloc-usable-tunables.c @@ -0,0 +1 @@ +#include <malloc/tst-malloc-usable.c> |