In some simple systems (like Busybox), the login shell might be run as init (PID 1). This leads to a case where LTP is run in the same session as init, thus setpgid is allowed to the PGID of init which results in a test fail. Indeed, the test retrieves the PGID of init to try and generate EPERM.
Instead get the PGID we use to generate EPERM from the kernel pid_max. It should not be used by any process, guaranteeing an invalid PGID and generating an EPERM error.
Signed-off-by: Teo Couprie Diaz teo.coupriediaz@arm.com Reviewed-by: Li Wang liwang@redhat.com Reviewed-by: Cyril Hrubis chrubis@suse.cz --- testcases/kernel/syscalls/setpgid/setpgid02.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/testcases/kernel/syscalls/setpgid/setpgid02.c b/testcases/kernel/syscalls/setpgid/setpgid02.c index 4b63afee8..b380d7df4 100644 --- a/testcases/kernel/syscalls/setpgid/setpgid02.c +++ b/testcases/kernel/syscalls/setpgid/setpgid02.c @@ -13,15 +13,15 @@ * - EINVAL when given pgid is less than 0. * - ESRCH when pid is not the calling process and not a child of * the calling process. - * - EPERM when an attempt was made to move a process into a process - * group in a different session. + * - EPERM when an attempt was made to move a process into a nonexisting + * process group. */
#include <errno.h> #include <unistd.h> #include "tst_test.h"
-static pid_t pgid, pid, ppid, init_pgid; +static pid_t pgid, pid, ppid, inval_pgid; static pid_t negative_pid = -1;
static struct tcase { @@ -31,7 +31,7 @@ static struct tcase { } tcases[] = { {&pid, &negative_pid, EINVAL}, {&ppid, &pgid, ESRCH}, - {&pid, &init_pgid, EPERM} + {&pid, &inval_pgid, EPERM} };
static void setup(void) @@ -41,10 +41,10 @@ static void setup(void) pgid = getpgrp();
/* - * Getting pgid of init/systemd process to use it as a - * process group from a different session for EPERM test + * pid_max would not be in use by another process and guarantees that + * it corresponds to an invalid PGID, generating EPERM. */ - init_pgid = SAFE_GETPGID(1); + SAFE_FILE_SCANF("/proc/sys/kernel/pid_max", "%d\n", &inval_pgid); }
static void run(unsigned int n)