From 4d392fa63af7f3fd09fdb49120864af1404d1a25 Mon Sep 17 00:00:00 2001 From: Michal Marek Date: Thu, 6 Mar 2014 18:03:46 +0100 Subject: [PATCH] testsuite: Fix uname() during glibc startup In a specific configuration (chroot with the linux32 personality), the modprobe_install_cmd_loop test failed, because the bash process handling the install command segfaulted. The backtrace showed a uname() call during libpthread initialization, at which point the environ pointer hadn't been initialized yet: Program terminated with signal SIGSEGV, Segmentation fault. #0 0x080c1591 in getenv (name=, name@entry=0xf775f850 "TESTSUITE_UNAME_R") at getenv.c:81 81 for (i = 0, len = strlen (name); environ[i]; i++) (gdb) bt #0 0x080c1591 in getenv (name=, name@entry=0xf775f850 "TESTSUITE_UNAME_R") at getenv.c:81 #1 0xf775f754 in uname (u=u@entry=0xff946350) at testsuite/uname.c:32 #2 0xf74ffc6c in is_smp_system () at ../nptl/sysdeps/unix/sysv/linux/i386/smp.h:39 #3 __pthread_initialize_minimal_internal () at nptl-init.c:460 #4 0xf74fe32c in _init () at ../sysdeps/i386/crti.S:74 #5 0x00000000 in ?? () (gdb) p environ $1 = (char **) 0x0 I don't know why it only happend in the chroot, but glibc can call its own functions and impose any restrictions before main() is started, so we have to adapt. Also, do not return error if there is an environment, but the environment variable is not found. If uname() is called by kmod, then the respective test will simply fail later. If it's something else calling uname(), then we do not want to disturb the program. Patch-mainline: v17 Git-commit: 632fb7b4634a540bb09af3b2004b3fe44cd4a214 --- testsuite/uname.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/testsuite/uname.c b/testsuite/uname.c index 2ada200..f55c435 100644 --- a/testsuite/uname.c +++ b/testsuite/uname.c @@ -22,6 +22,7 @@ #include #include #include +#include #include "testsuite.h" @@ -29,17 +30,10 @@ TS_EXPORT int uname(struct utsname *u) { static void *nextlib = NULL; static int (*nextlib_uname)(struct utsname *u); - const char *release = getenv(S_TC_UNAME_R); + const char *release; int err; size_t sz; - if (release == NULL) { - fprintf(stderr, "TRAP uname(): missing export %s?\n", - S_TC_UNAME_R); - errno = EFAULT; - return -1; - } - if (nextlib == NULL) { #ifdef RTLD_NEXT nextlib = RTLD_NEXT; @@ -53,6 +47,20 @@ TS_EXPORT int uname(struct utsname *u) if (err < 0) return err; + if (!environ) + /* + * probably called from within glibc before main(); unsafe + * to call getenv() + */ + return 0; + + release = getenv(S_TC_UNAME_R); + if (release == NULL) { + fprintf(stderr, "TRAP uname(): missing export %s?\n", + S_TC_UNAME_R); + return 0; + } + sz = strlen(release) + 1; if (sz > sizeof(u->release)) { fprintf(stderr, "uname(): sizeof release (%s) " -- 1.8.4.5