Read from /proc/self/syscall should yield read system call and correct args in the output as current is reading /proc/self/syscall.
Signed-off-by: Alexey Dobriyan <[email protected]> --- tools/testing/selftests/proc/.gitignore | 3 + tools/testing/selftests/proc/Makefile | 1 tools/testing/selftests/proc/proc-self-syscall.c | 45 +++++++++++++++++++++++ 3 files changed, 48 insertions(+), 1 deletion(-) --- a/tools/testing/selftests/proc/.gitignore +++ b/tools/testing/selftests/proc/.gitignore @@ -1 +1,2 @@ -/proc-self-wchan +/proc-self-mem +/proc-self-syscall --- a/tools/testing/selftests/proc/Makefile +++ b/tools/testing/selftests/proc/Makefile @@ -1,6 +1,7 @@ CFLAGS += -Wall -O2 TEST_GEN_PROGS := +TEST_GEN_PROGS += proc-self-syscall TEST_GEN_PROGS += proc-self-wchan include ../lib.mk new file mode 100644 --- /dev/null +++ b/tools/testing/selftests/proc/proc-self-syscall.c @@ -0,0 +1,45 @@ +#define _GNU_SOURCE +#include <unistd.h> +#include <sys/syscall.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#include <unistd.h> +#include <string.h> +#include <stdio.h> + +static inline ssize_t sys_read(int fd, void *buf, size_t len) +{ + return syscall(SYS_read, fd, buf, len); +} + +int main(void) +{ + char buf1[64]; + char buf2[64]; + int fd; + ssize_t rv; + + fd = open("/proc/self/syscall", O_RDONLY); + if (fd == -1) { + if (errno == ENOENT) + return 2; + return 1; + } + + /* Do direct system call as libc can wrap anything. */ + snprintf(buf1, sizeof(buf1), "%ld 0x%lx 0x%lx 0x%lx", + (long)SYS_read, (long)fd, (long)buf2, (long)sizeof(buf2)); + + memset(buf2, 0, sizeof(buf2)); + rv = sys_read(fd, buf2, sizeof(buf2)); + if (rv < 0) + return 1; + if (rv < strlen(buf1)) + return 1; + if (strncmp(buf1, buf2, strlen(buf1)) != 0) + return 1; + + return 0; +}
