From: Alexey Dobriyan <adobriyan@xxxxxxxxx> Subject: proc: add selftest for last field of /proc/loadavg Test fork counter formerly known as ->last_pid, the only part of /proc/loadavg which can be tested. Testing in init pid namespace is not reliable because of background activity. Link: http://lkml.kernel.org/r/20180311152241.GA26247@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/proc/.gitignore | 1 tools/testing/selftests/proc/Makefile | 1 tools/testing/selftests/proc/proc-loadavg-001.c | 83 ++++++++++++++ 3 files changed, 85 insertions(+) diff -puN tools/testing/selftests/proc/.gitignore~proc-test-last-field-of-proc-loadavg tools/testing/selftests/proc/.gitignore --- a/tools/testing/selftests/proc/.gitignore~proc-test-last-field-of-proc-loadavg +++ a/tools/testing/selftests/proc/.gitignore @@ -1,3 +1,4 @@ +/proc-loadavg-001 /proc-self-map-files-001 /proc-self-map-files-002 /proc-self-syscall diff -puN tools/testing/selftests/proc/Makefile~proc-test-last-field-of-proc-loadavg tools/testing/selftests/proc/Makefile --- a/tools/testing/selftests/proc/Makefile~proc-test-last-field-of-proc-loadavg +++ a/tools/testing/selftests/proc/Makefile @@ -1,6 +1,7 @@ CFLAGS += -Wall -O2 TEST_GEN_PROGS := +TEST_GEN_PROGS += proc-loadavg-001 TEST_GEN_PROGS += proc-self-map-files-001 TEST_GEN_PROGS += proc-self-map-files-002 TEST_GEN_PROGS += proc-self-syscall diff -puN /dev/null tools/testing/selftests/proc/proc-loadavg-001.c --- /dev/null +++ a/tools/testing/selftests/proc/proc-loadavg-001.c @@ -0,0 +1,83 @@ +/* + * Copyright _ 2018 Alexey Dobriyan <adobriyan@xxxxxxxxx> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +/* Test that /proc/loadavg correctly reports last pid in pid namespace. */ +#define _GNU_SOURCE +#include <errno.h> +#include <sched.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#include <sys/wait.h> + +int main(void) +{ + pid_t pid; + int wstatus; + + if (unshare(CLONE_NEWPID) == -1) { + if (errno == ENOSYS || errno == EPERM) + return 2; + return 1; + } + + pid = fork(); + if (pid == -1) + return 1; + if (pid == 0) { + char buf[128], *p; + int fd; + ssize_t rv; + + fd = open("/proc/loadavg" , O_RDONLY); + if (fd == -1) + return 1; + rv = read(fd, buf, sizeof(buf)); + if (rv < 3) + return 1; + p = buf + rv; + + /* pid 1 */ + if (!(p[-3] == ' ' && p[-2] == '1' && p[-1] == '\n')) + return 1; + + pid = fork(); + if (pid == -1) + return 1; + if (pid == 0) + return 0; + if (waitpid(pid, NULL, 0) == -1) + return 1; + + lseek(fd, 0, SEEK_SET); + rv = read(fd, buf, sizeof(buf)); + if (rv < 3) + return 1; + p = buf + rv; + + /* pid 2 */ + if (!(p[-3] == ' ' && p[-2] == '2' && p[-1] == '\n')) + return 1; + + return 0; + } + + if (waitpid(pid, &wstatus, 0) == -1) + return 1; + if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) + return 0; + return 1; +} _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
