From: Alexey Dobriyan <adobriyan@xxxxxxxxx> Subject: proc: test /proc/self symlink There are plans to change how /proc/self result is calculated, for that a test is necessary. Use direct system call because of this whole getpid caching story. Link: http://lkml.kernel.org/r/20180627195103.GB18113@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/proc/.gitignore | 1 tools/testing/selftests/proc/Makefile | 2 + tools/testing/selftests/proc/proc.h | 7 +++ tools/testing/selftests/proc/self.c | 39 ++++++++++++++++++++++ 4 files changed, 49 insertions(+) --- a/tools/testing/selftests/proc/.gitignore~proc-test-proc-self-symlink +++ a/tools/testing/selftests/proc/.gitignore @@ -9,3 +9,4 @@ /proc-uptime-001 /proc-uptime-002 /read +/self --- a/tools/testing/selftests/proc/Makefile~proc-test-proc-self-symlink +++ a/tools/testing/selftests/proc/Makefile @@ -1,4 +1,5 @@ CFLAGS += -Wall -O2 -Wno-unused-function +CFLAGS += -D_GNU_SOURCE TEST_GEN_PROGS := TEST_GEN_PROGS += fd-001-lookup @@ -12,5 +13,6 @@ TEST_GEN_PROGS += proc-self-wchan TEST_GEN_PROGS += proc-uptime-001 TEST_GEN_PROGS += proc-uptime-002 TEST_GEN_PROGS += read +TEST_GEN_PROGS += self include ../lib.mk --- a/tools/testing/selftests/proc/proc.h~proc-test-proc-self-symlink +++ a/tools/testing/selftests/proc/proc.h @@ -6,6 +6,13 @@ #include <stdbool.h> #include <stdlib.h> #include <string.h> +#include <unistd.h> +#include <sys/syscall.h> + +static inline pid_t sys_getpid(void) +{ + return syscall(SYS_getpid); +} static inline bool streq(const char *s1, const char *s2) { --- /dev/null +++ a/tools/testing/selftests/proc/self.c @@ -0,0 +1,39 @@ +/* + * 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/self gives correct TGID. +#undef NDEBUG +#include <assert.h> +#include <stdio.h> +#include <unistd.h> + +#include "proc.h" + +int main(void) +{ + char buf1[64], buf2[64]; + pid_t pid; + ssize_t rv; + + pid = sys_getpid(); + snprintf(buf1, sizeof(buf1), "%u", pid); + + rv = readlink("/proc/self", buf2, sizeof(buf2)); + assert(rv == strlen(buf1)); + buf2[rv] = '\0'; + assert(streq(buf1, buf2)); + + return 0; +} _
