Message ID | 20191115135901.8114-1-ethercflow@gmail.com |
---|---|
State | Changes Requested |
Delegated to: | BPF Maintainers |
Headers | show |
Series | [bpf-next,v4] selftests/bpf: test for bpf_get_file_path() from raw tracepoint | expand |
On Fri, Nov 15, 2019 at 5:59 AM Wenbo Zhang <ethercflow@gmail.com> wrote: > > trace fstat events by raw tracepoint sys_enter:newfstat, and handle events > only produced by test_file_get_path, which call fstat on several different > types of files to test bpf_get_file_path's feature. > > v3->v4: addressed Andrii's feedback > - use a set of fd instead of fds array > - use global variables instead of maps (in v3, I mistakenly thought that > the bpf maps are global variables.) > - remove uncessary global variable path_info_index > - remove fd compare as the fstat's order is fixed > > v2->v3: addressed Andrii's feedback > - use global data instead of perf_buffer to simplified code > > v1->v2: addressed Daniel's feedback > - rename bpf_fd2path to bpf_get_file_path to be consistent with other > helper's names > > Signed-off-by: Wenbo Zhang <ethercflow@gmail.com> > --- I like this much better, so much simpler BPF program and userspace parts has less unnecessary moving pieces. I just have minor nits below. But I think you should send this patch together with the patch adding helper as one patch series. Both patches are either going to get accepted together, or declined together; having them as a patch set is more meaningful. > .../selftests/bpf/prog_tests/get_file_path.c | 173 ++++++++++++++++++ > .../selftests/bpf/progs/test_get_file_path.c | 43 +++++ > 2 files changed, 216 insertions(+) > create mode 100644 tools/testing/selftests/bpf/prog_tests/get_file_path.c > create mode 100644 tools/testing/selftests/bpf/progs/test_get_file_path.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/get_file_path.c b/tools/testing/selftests/bpf/prog_tests/get_file_path.c > new file mode 100644 > index 000000000000..446ee4dd20e2 > --- /dev/null > +++ b/tools/testing/selftests/bpf/prog_tests/get_file_path.c > @@ -0,0 +1,173 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#define _GNU_SOURCE > +#include <test_progs.h> > +#include <sys/stat.h> > +#include <linux/sched.h> > +#include <sys/syscall.h> > + > +#define MAX_PATH_LEN 128 > +#define MAX_FDS 7 > +#define MAX_EVENT_NUM 16 > + > +static struct file_path_test_data { > + pid_t pid; > + __u32 cnt; > + __u32 fds[MAX_EVENT_NUM]; > + char paths[MAX_EVENT_NUM][MAX_PATH_LEN]; > +} src, dst; > + > +static inline int set_pathname(int fd) > +{ > + char buf[MAX_PATH_LEN]; > + > + snprintf(buf, MAX_PATH_LEN, "/proc/%d/fd/%d", src.pid, fd); > + src.fds[src.cnt] = fd; > + return readlink(buf, src.paths[src.cnt++], MAX_PATH_LEN); > +} > + > +static int trigger_fstat_events(pid_t pid) > +{ > + int pipefd[2] = { -1, -1 }; > + int sockfd = -1, procfd = -1, devfd = -1; > + int localfd = -1, indicatorfd = -1; > + struct stat fileStat; > + int ret = -1; > + > + /* unmountable pseudo-filesystems */ > + if (CHECK_FAIL(pipe(pipefd) < 0)) > + return ret; > + /* unmountable pseudo-filesystems */ > + sockfd = socket(AF_INET, SOCK_STREAM, 0); > + if (CHECK_FAIL(sockfd < 0)) > + goto out_close; > + /* mountable pseudo-filesystems */ > + procfd = open("/proc/self/comm", O_RDONLY); > + if (CHECK_FAIL(procfd < 0)) > + goto out_close; > + devfd = open("/dev/urandom", O_RDONLY); > + if (CHECK_FAIL(devfd < 0)) > + goto out_close; > + localfd = open("/tmp/fd2path_loadgen.txt", O_CREAT|O_RDONLY); > + if (CHECK_FAIL(localfd < 0)) > + goto out_close; > + /* bpf_get_file_path will return path with (deleted) */ > + remove("/tmp/fd2path_loadgen.txt"); > + indicatorfd = open("/tmp/", O_PATH); > + if (CHECK_FAIL(indicatorfd < 0)) > + goto out_close; > + > + src.pid = pid; > + > + ret = set_pathname(pipefd[0]); > + if (CHECK_FAIL(ret < 0)) > + goto out_close; > + ret = set_pathname(pipefd[1]); > + if (CHECK_FAIL(ret < 0)) > + goto out_close; > + ret = set_pathname(sockfd); > + if (CHECK_FAIL(ret < 0)) > + goto out_close; > + ret = set_pathname(procfd); > + if (CHECK_FAIL(ret < 0)) > + goto out_close; > + ret = set_pathname(devfd); > + if (CHECK_FAIL(ret < 0)) > + goto out_close; > + ret = set_pathname(localfd); > + if (CHECK_FAIL(ret < 0)) > + goto out_close; > + ret = set_pathname(indicatorfd); > + if (CHECK_FAIL(ret < 0)) > + goto out_close; > + > + fstat(pipefd[0], &fileStat); > + fstat(pipefd[1], &fileStat); > + fstat(sockfd, &fileStat); > + fstat(procfd, &fileStat); > + fstat(devfd, &fileStat); > + fstat(localfd, &fileStat); > + fstat(indicatorfd, &fileStat); > + > +out_close: > + close(indicatorfd); > + close(localfd); > + close(devfd); > + close(procfd); > + close(sockfd); > + close(pipefd[1]); > + close(pipefd[0]); > + > + return ret; > +} > + > +void test_get_file_path(void) > +{ > + const char *prog_name = "tracepoint/syscalls/sys_enter_newfstat"; > + const char *obj_file = "./test_get_file_path.o"; > + DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, ); > + int err, results_map_fd, duration = 0; > + struct bpf_program *tp_prog = NULL; > + struct bpf_link *tp_link = NULL; > + struct bpf_object *obj = NULL; > + const int zero = 0; > + > + obj = bpf_object__open_file(obj_file, &opts); you can just pass NULL for opts, as you are not really using any > + if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) > + return; > + > + tp_prog = bpf_object__find_program_by_title(obj, prog_name); > + if (CHECK(!tp_prog, "find_tp", > + "prog '%s' not found\n", prog_name)) > + goto cleanup; > + > + err = bpf_object__load(obj); > + if (CHECK(err, "obj_load", "err %d\n", err)) > + goto cleanup; > + > + results_map_fd = bpf_find_map(__func__, obj, "test_get.bss"); > + if (CHECK(results_map_fd < 0, "find_bss_map", > + "err %d\n", results_map_fd)) > + goto cleanup; > + > + tp_link = bpf_program__attach_tracepoint(tp_prog, "syscalls", > + "sys_enter_newfstat"); your patch subject says "raw tracepoint", but you are really using a normal tracepoint here > + if (CHECK(IS_ERR(tp_link), "attach_tp", > + "err %ld\n", PTR_ERR(tp_link))) { > + tp_link = NULL; > + goto cleanup; > + } > + > + dst.pid = syscall(SYS_gettid); see comment below, you can just use getpid(), as this test is single-threaded > + err = bpf_map_update_elem(results_map_fd, &zero, &dst, 0); > + if (CHECK(err, "update_elem", > + "failed to set pid filter: %d\n", err)) > + goto cleanup; > + > + err = trigger_fstat_events(dst.pid); > + if (CHECK_FAIL(err < 0)) > + goto cleanup; > + > + err = bpf_map_lookup_elem(results_map_fd, &zero, &dst); > + if (CHECK(err, "get_results", > + "failed to get results: %d\n", err)) > + goto cleanup; > + > + for (int i = 0; i < MAX_FDS; i++) { > + if (i < 3) { > + CHECK((dst.paths[i][0] != '\0'), "get_file_path", nit: unnecessary parens around check > + "failed to filter fs [%d]: %u(%s) vs %u(%s)\n", > + i, src.fds[i], src.paths[i], dst.fds[i], > + dst.paths[i]); > + } else { > + err = strncmp(src.paths[i], dst.paths[i], MAX_PATH_LEN); > + CHECK(err != 0, "get_file_path", > + "failed to get path[%d]: %u(%s) vs %u(%s)\n", > + i, src.fds[i], src.paths[i], dst.fds[i], > + dst.paths[i]); > + } > + } > + > +cleanup: > + bpf_link__destroy(tp_link); > + bpf_object__close(obj); > +} > diff --git a/tools/testing/selftests/bpf/progs/test_get_file_path.c b/tools/testing/selftests/bpf/progs/test_get_file_path.c > new file mode 100644 > index 000000000000..c006fa05e32b > --- /dev/null > +++ b/tools/testing/selftests/bpf/progs/test_get_file_path.c > @@ -0,0 +1,43 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include <linux/bpf.h> > +#include <linux/ptrace.h> > +#include <string.h> > +#include <unistd.h> > +#include "bpf_helpers.h" > +#include "bpf_tracing.h" > + > +#define MAX_PATH_LEN 128 > +#define MAX_EVENT_NUM 16 > + > +static struct file_path_test_data { > + pid_t pid; > + __u32 cnt; > + __u32 fds[MAX_EVENT_NUM]; > + char paths[MAX_EVENT_NUM][MAX_PATH_LEN]; > +} data; > + > +struct sys_enter_newfstat_args { > + unsigned long long pad1; > + unsigned long long pad2; > + unsigned int fd; > +}; > + > +SEC("tracepoint/syscalls/sys_enter_newfstat") > +int bpf_prog(struct sys_enter_newfstat_args *args) > +{ > + pid_t pid = bpf_get_current_pid_tgid(); you don't have to use thread id, given test_progs is single-threaded, so can do (bpf_get_current_pid_tgid() >> 32) here and use getpid() in userspace part. > + > + if (pid != data.pid) > + return 0; > + if (data.cnt >= MAX_EVENT_NUM) > + return 0; > + > + data.fds[data.cnt] = args->fd; > + bpf_get_file_path(data.paths[data.cnt], MAX_PATH_LEN, args->fd); > + data.cnt++; > + > + return 0; > +} > + > +char _license[] SEC("license") = "GPL"; > -- > 2.17.1 >
> I like this much better, so much simpler BPF program and userspace > parts has less unnecessary moving pieces. I just have minor nits > below. Thank you for your patience, you're so sweet. I've read your comments and will fix them and resubmit as patchset. > you can just pass NULL for opts, as you are not really using any Agree, and I found if opt is NULL, > const char *obj_file = "./test_get_file_path.o"; must be changed to "test_get_file_path.o", or bpf_obj_name_cpy will return -EINVAL. :) > your patch subject says "raw tracepoint", but you are really using a > normal tracepoint here Sorry for this, I'll make it keep up with the code > see comment below, you can just use getpid(), as this test is single-threaded > you don't have to use thread id, given test_progs is single-threaded, > so can do (bpf_get_current_pid_tgid() >> 32) here and use getpid() in > userspace part. I found I was thinking too much. I thought test_progs maybe multi-threaded one day, so I used SYS_gettid. I feel that it is very bad now. It will make people misunderstand that it is multi-threaded. Thank you for point it out. > nit: unnecessary parens around check Agree, I'll fix this. Thank you. Andrii Nakryiko <andrii.nakryiko@gmail.com> 于2019年11月18日周一 下午2:45写道: > > On Fri, Nov 15, 2019 at 5:59 AM Wenbo Zhang <ethercflow@gmail.com> wrote: > > > > trace fstat events by raw tracepoint sys_enter:newfstat, and handle events > > only produced by test_file_get_path, which call fstat on several different > > types of files to test bpf_get_file_path's feature. > > > > v3->v4: addressed Andrii's feedback > > - use a set of fd instead of fds array > > - use global variables instead of maps (in v3, I mistakenly thought that > > the bpf maps are global variables.) > > - remove uncessary global variable path_info_index > > - remove fd compare as the fstat's order is fixed > > > > v2->v3: addressed Andrii's feedback > > - use global data instead of perf_buffer to simplified code > > > > v1->v2: addressed Daniel's feedback > > - rename bpf_fd2path to bpf_get_file_path to be consistent with other > > helper's names > > > > Signed-off-by: Wenbo Zhang <ethercflow@gmail.com> > > --- > > I like this much better, so much simpler BPF program and userspace > parts has less unnecessary moving pieces. I just have minor nits > below. > > But I think you should send this patch together with the patch adding > helper as one patch series. Both patches are either going to get > accepted together, or declined together; having them as a patch set is > more meaningful. > > > .../selftests/bpf/prog_tests/get_file_path.c | 173 ++++++++++++++++++ > > .../selftests/bpf/progs/test_get_file_path.c | 43 +++++ > > 2 files changed, 216 insertions(+) > > create mode 100644 tools/testing/selftests/bpf/prog_tests/get_file_path.c > > create mode 100644 tools/testing/selftests/bpf/progs/test_get_file_path.c > > > > diff --git a/tools/testing/selftests/bpf/prog_tests/get_file_path.c b/tools/testing/selftests/bpf/prog_tests/get_file_path.c > > new file mode 100644 > > index 000000000000..446ee4dd20e2 > > --- /dev/null > > +++ b/tools/testing/selftests/bpf/prog_tests/get_file_path.c > > @@ -0,0 +1,173 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +#define _GNU_SOURCE > > +#include <test_progs.h> > > +#include <sys/stat.h> > > +#include <linux/sched.h> > > +#include <sys/syscall.h> > > + > > +#define MAX_PATH_LEN 128 > > +#define MAX_FDS 7 > > +#define MAX_EVENT_NUM 16 > > + > > +static struct file_path_test_data { > > + pid_t pid; > > + __u32 cnt; > > + __u32 fds[MAX_EVENT_NUM]; > > + char paths[MAX_EVENT_NUM][MAX_PATH_LEN]; > > +} src, dst; > > + > > +static inline int set_pathname(int fd) > > +{ > > + char buf[MAX_PATH_LEN]; > > + > > + snprintf(buf, MAX_PATH_LEN, "/proc/%d/fd/%d", src.pid, fd); > > + src.fds[src.cnt] = fd; > > + return readlink(buf, src.paths[src.cnt++], MAX_PATH_LEN); > > +} > > + > > +static int trigger_fstat_events(pid_t pid) > > +{ > > + int pipefd[2] = { -1, -1 }; > > + int sockfd = -1, procfd = -1, devfd = -1; > > + int localfd = -1, indicatorfd = -1; > > + struct stat fileStat; > > + int ret = -1; > > + > > + /* unmountable pseudo-filesystems */ > > + if (CHECK_FAIL(pipe(pipefd) < 0)) > > + return ret; > > + /* unmountable pseudo-filesystems */ > > + sockfd = socket(AF_INET, SOCK_STREAM, 0); > > + if (CHECK_FAIL(sockfd < 0)) > > + goto out_close; > > + /* mountable pseudo-filesystems */ > > + procfd = open("/proc/self/comm", O_RDONLY); > > + if (CHECK_FAIL(procfd < 0)) > > + goto out_close; > > + devfd = open("/dev/urandom", O_RDONLY); > > + if (CHECK_FAIL(devfd < 0)) > > + goto out_close; > > + localfd = open("/tmp/fd2path_loadgen.txt", O_CREAT|O_RDONLY); > > + if (CHECK_FAIL(localfd < 0)) > > + goto out_close; > > + /* bpf_get_file_path will return path with (deleted) */ > > + remove("/tmp/fd2path_loadgen.txt"); > > + indicatorfd = open("/tmp/", O_PATH); > > + if (CHECK_FAIL(indicatorfd < 0)) > > + goto out_close; > > + > > + src.pid = pid; > > + > > + ret = set_pathname(pipefd[0]); > > + if (CHECK_FAIL(ret < 0)) > > + goto out_close; > > + ret = set_pathname(pipefd[1]); > > + if (CHECK_FAIL(ret < 0)) > > + goto out_close; > > + ret = set_pathname(sockfd); > > + if (CHECK_FAIL(ret < 0)) > > + goto out_close; > > + ret = set_pathname(procfd); > > + if (CHECK_FAIL(ret < 0)) > > + goto out_close; > > + ret = set_pathname(devfd); > > + if (CHECK_FAIL(ret < 0)) > > + goto out_close; > > + ret = set_pathname(localfd); > > + if (CHECK_FAIL(ret < 0)) > > + goto out_close; > > + ret = set_pathname(indicatorfd); > > + if (CHECK_FAIL(ret < 0)) > > + goto out_close; > > + > > + fstat(pipefd[0], &fileStat); > > + fstat(pipefd[1], &fileStat); > > + fstat(sockfd, &fileStat); > > + fstat(procfd, &fileStat); > > + fstat(devfd, &fileStat); > > + fstat(localfd, &fileStat); > > + fstat(indicatorfd, &fileStat); > > + > > +out_close: > > + close(indicatorfd); > > + close(localfd); > > + close(devfd); > > + close(procfd); > > + close(sockfd); > > + close(pipefd[1]); > > + close(pipefd[0]); > > + > > + return ret; > > +} > > + > > +void test_get_file_path(void) > > +{ > > + const char *prog_name = "tracepoint/syscalls/sys_enter_newfstat"; > > + const char *obj_file = "./test_get_file_path.o"; > > + DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, ); > > + int err, results_map_fd, duration = 0; > > + struct bpf_program *tp_prog = NULL; > > + struct bpf_link *tp_link = NULL; > > + struct bpf_object *obj = NULL; > > + const int zero = 0; > > + > > + obj = bpf_object__open_file(obj_file, &opts); > > you can just pass NULL for opts, as you are not really using any > > > + if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) > > + return; > > + > > + tp_prog = bpf_object__find_program_by_title(obj, prog_name); > > + if (CHECK(!tp_prog, "find_tp", > > + "prog '%s' not found\n", prog_name)) > > + goto cleanup; > > + > > + err = bpf_object__load(obj); > > + if (CHECK(err, "obj_load", "err %d\n", err)) > > + goto cleanup; > > + > > + results_map_fd = bpf_find_map(__func__, obj, "test_get.bss"); > > + if (CHECK(results_map_fd < 0, "find_bss_map", > > + "err %d\n", results_map_fd)) > > + goto cleanup; > > + > > + tp_link = bpf_program__attach_tracepoint(tp_prog, "syscalls", > > + "sys_enter_newfstat"); > > your patch subject says "raw tracepoint", but you are really using a > normal tracepoint here > > > + if (CHECK(IS_ERR(tp_link), "attach_tp", > > + "err %ld\n", PTR_ERR(tp_link))) { > > + tp_link = NULL; > > + goto cleanup; > > + } > > + > > + dst.pid = syscall(SYS_gettid); > > see comment below, you can just use getpid(), as this test is single-threaded > > > + err = bpf_map_update_elem(results_map_fd, &zero, &dst, 0); > > + if (CHECK(err, "update_elem", > > + "failed to set pid filter: %d\n", err)) > > + goto cleanup; > > + > > + err = trigger_fstat_events(dst.pid); > > + if (CHECK_FAIL(err < 0)) > > + goto cleanup; > > + > > + err = bpf_map_lookup_elem(results_map_fd, &zero, &dst); > > + if (CHECK(err, "get_results", > > + "failed to get results: %d\n", err)) > > + goto cleanup; > > + > > + for (int i = 0; i < MAX_FDS; i++) { > > + if (i < 3) { > > + CHECK((dst.paths[i][0] != '\0'), "get_file_path", > > nit: unnecessary parens around check > > > + "failed to filter fs [%d]: %u(%s) vs %u(%s)\n", > > + i, src.fds[i], src.paths[i], dst.fds[i], > > + dst.paths[i]); > > + } else { > > + err = strncmp(src.paths[i], dst.paths[i], MAX_PATH_LEN); > > + CHECK(err != 0, "get_file_path", > > + "failed to get path[%d]: %u(%s) vs %u(%s)\n", > > + i, src.fds[i], src.paths[i], dst.fds[i], > > + dst.paths[i]); > > + } > > + } > > + > > +cleanup: > > + bpf_link__destroy(tp_link); > > + bpf_object__close(obj); > > +} > > diff --git a/tools/testing/selftests/bpf/progs/test_get_file_path.c b/tools/testing/selftests/bpf/progs/test_get_file_path.c > > new file mode 100644 > > index 000000000000..c006fa05e32b > > --- /dev/null > > +++ b/tools/testing/selftests/bpf/progs/test_get_file_path.c > > @@ -0,0 +1,43 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > + > > +#include <linux/bpf.h> > > +#include <linux/ptrace.h> > > +#include <string.h> > > +#include <unistd.h> > > +#include "bpf_helpers.h" > > +#include "bpf_tracing.h" > > + > > +#define MAX_PATH_LEN 128 > > +#define MAX_EVENT_NUM 16 > > + > > +static struct file_path_test_data { > > + pid_t pid; > > + __u32 cnt; > > + __u32 fds[MAX_EVENT_NUM]; > > + char paths[MAX_EVENT_NUM][MAX_PATH_LEN]; > > +} data; > > + > > +struct sys_enter_newfstat_args { > > + unsigned long long pad1; > > + unsigned long long pad2; > > + unsigned int fd; > > +}; > > + > > +SEC("tracepoint/syscalls/sys_enter_newfstat") > > +int bpf_prog(struct sys_enter_newfstat_args *args) > > +{ > > + pid_t pid = bpf_get_current_pid_tgid(); > > you don't have to use thread id, given test_progs is single-threaded, > so can do (bpf_get_current_pid_tgid() >> 32) here and use getpid() in > userspace part. > > > + > > + if (pid != data.pid) > > + return 0; > > + if (data.cnt >= MAX_EVENT_NUM) > > + return 0; > > + > > + data.fds[data.cnt] = args->fd; > > + bpf_get_file_path(data.paths[data.cnt], MAX_PATH_LEN, args->fd); > > + data.cnt++; > > + > > + return 0; > > +} > > + > > +char _license[] SEC("license") = "GPL"; > > -- > > 2.17.1 > >
diff --git a/tools/testing/selftests/bpf/prog_tests/get_file_path.c b/tools/testing/selftests/bpf/prog_tests/get_file_path.c new file mode 100644 index 000000000000..446ee4dd20e2 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/get_file_path.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <test_progs.h> +#include <sys/stat.h> +#include <linux/sched.h> +#include <sys/syscall.h> + +#define MAX_PATH_LEN 128 +#define MAX_FDS 7 +#define MAX_EVENT_NUM 16 + +static struct file_path_test_data { + pid_t pid; + __u32 cnt; + __u32 fds[MAX_EVENT_NUM]; + char paths[MAX_EVENT_NUM][MAX_PATH_LEN]; +} src, dst; + +static inline int set_pathname(int fd) +{ + char buf[MAX_PATH_LEN]; + + snprintf(buf, MAX_PATH_LEN, "/proc/%d/fd/%d", src.pid, fd); + src.fds[src.cnt] = fd; + return readlink(buf, src.paths[src.cnt++], MAX_PATH_LEN); +} + +static int trigger_fstat_events(pid_t pid) +{ + int pipefd[2] = { -1, -1 }; + int sockfd = -1, procfd = -1, devfd = -1; + int localfd = -1, indicatorfd = -1; + struct stat fileStat; + int ret = -1; + + /* unmountable pseudo-filesystems */ + if (CHECK_FAIL(pipe(pipefd) < 0)) + return ret; + /* unmountable pseudo-filesystems */ + sockfd = socket(AF_INET, SOCK_STREAM, 0); + if (CHECK_FAIL(sockfd < 0)) + goto out_close; + /* mountable pseudo-filesystems */ + procfd = open("/proc/self/comm", O_RDONLY); + if (CHECK_FAIL(procfd < 0)) + goto out_close; + devfd = open("/dev/urandom", O_RDONLY); + if (CHECK_FAIL(devfd < 0)) + goto out_close; + localfd = open("/tmp/fd2path_loadgen.txt", O_CREAT|O_RDONLY); + if (CHECK_FAIL(localfd < 0)) + goto out_close; + /* bpf_get_file_path will return path with (deleted) */ + remove("/tmp/fd2path_loadgen.txt"); + indicatorfd = open("/tmp/", O_PATH); + if (CHECK_FAIL(indicatorfd < 0)) + goto out_close; + + src.pid = pid; + + ret = set_pathname(pipefd[0]); + if (CHECK_FAIL(ret < 0)) + goto out_close; + ret = set_pathname(pipefd[1]); + if (CHECK_FAIL(ret < 0)) + goto out_close; + ret = set_pathname(sockfd); + if (CHECK_FAIL(ret < 0)) + goto out_close; + ret = set_pathname(procfd); + if (CHECK_FAIL(ret < 0)) + goto out_close; + ret = set_pathname(devfd); + if (CHECK_FAIL(ret < 0)) + goto out_close; + ret = set_pathname(localfd); + if (CHECK_FAIL(ret < 0)) + goto out_close; + ret = set_pathname(indicatorfd); + if (CHECK_FAIL(ret < 0)) + goto out_close; + + fstat(pipefd[0], &fileStat); + fstat(pipefd[1], &fileStat); + fstat(sockfd, &fileStat); + fstat(procfd, &fileStat); + fstat(devfd, &fileStat); + fstat(localfd, &fileStat); + fstat(indicatorfd, &fileStat); + +out_close: + close(indicatorfd); + close(localfd); + close(devfd); + close(procfd); + close(sockfd); + close(pipefd[1]); + close(pipefd[0]); + + return ret; +} + +void test_get_file_path(void) +{ + const char *prog_name = "tracepoint/syscalls/sys_enter_newfstat"; + const char *obj_file = "./test_get_file_path.o"; + DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, ); + int err, results_map_fd, duration = 0; + struct bpf_program *tp_prog = NULL; + struct bpf_link *tp_link = NULL; + struct bpf_object *obj = NULL; + const int zero = 0; + + obj = bpf_object__open_file(obj_file, &opts); + if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) + return; + + tp_prog = bpf_object__find_program_by_title(obj, prog_name); + if (CHECK(!tp_prog, "find_tp", + "prog '%s' not found\n", prog_name)) + goto cleanup; + + err = bpf_object__load(obj); + if (CHECK(err, "obj_load", "err %d\n", err)) + goto cleanup; + + results_map_fd = bpf_find_map(__func__, obj, "test_get.bss"); + if (CHECK(results_map_fd < 0, "find_bss_map", + "err %d\n", results_map_fd)) + goto cleanup; + + tp_link = bpf_program__attach_tracepoint(tp_prog, "syscalls", + "sys_enter_newfstat"); + if (CHECK(IS_ERR(tp_link), "attach_tp", + "err %ld\n", PTR_ERR(tp_link))) { + tp_link = NULL; + goto cleanup; + } + + dst.pid = syscall(SYS_gettid); + err = bpf_map_update_elem(results_map_fd, &zero, &dst, 0); + if (CHECK(err, "update_elem", + "failed to set pid filter: %d\n", err)) + goto cleanup; + + err = trigger_fstat_events(dst.pid); + if (CHECK_FAIL(err < 0)) + goto cleanup; + + err = bpf_map_lookup_elem(results_map_fd, &zero, &dst); + if (CHECK(err, "get_results", + "failed to get results: %d\n", err)) + goto cleanup; + + for (int i = 0; i < MAX_FDS; i++) { + if (i < 3) { + CHECK((dst.paths[i][0] != '\0'), "get_file_path", + "failed to filter fs [%d]: %u(%s) vs %u(%s)\n", + i, src.fds[i], src.paths[i], dst.fds[i], + dst.paths[i]); + } else { + err = strncmp(src.paths[i], dst.paths[i], MAX_PATH_LEN); + CHECK(err != 0, "get_file_path", + "failed to get path[%d]: %u(%s) vs %u(%s)\n", + i, src.fds[i], src.paths[i], dst.fds[i], + dst.paths[i]); + } + } + +cleanup: + bpf_link__destroy(tp_link); + bpf_object__close(obj); +} diff --git a/tools/testing/selftests/bpf/progs/test_get_file_path.c b/tools/testing/selftests/bpf/progs/test_get_file_path.c new file mode 100644 index 000000000000..c006fa05e32b --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_get_file_path.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/bpf.h> +#include <linux/ptrace.h> +#include <string.h> +#include <unistd.h> +#include "bpf_helpers.h" +#include "bpf_tracing.h" + +#define MAX_PATH_LEN 128 +#define MAX_EVENT_NUM 16 + +static struct file_path_test_data { + pid_t pid; + __u32 cnt; + __u32 fds[MAX_EVENT_NUM]; + char paths[MAX_EVENT_NUM][MAX_PATH_LEN]; +} data; + +struct sys_enter_newfstat_args { + unsigned long long pad1; + unsigned long long pad2; + unsigned int fd; +}; + +SEC("tracepoint/syscalls/sys_enter_newfstat") +int bpf_prog(struct sys_enter_newfstat_args *args) +{ + pid_t pid = bpf_get_current_pid_tgid(); + + if (pid != data.pid) + return 0; + if (data.cnt >= MAX_EVENT_NUM) + return 0; + + data.fds[data.cnt] = args->fd; + bpf_get_file_path(data.paths[data.cnt], MAX_PATH_LEN, args->fd); + data.cnt++; + + return 0; +} + +char _license[] SEC("license") = "GPL";
trace fstat events by raw tracepoint sys_enter:newfstat, and handle events only produced by test_file_get_path, which call fstat on several different types of files to test bpf_get_file_path's feature. v3->v4: addressed Andrii's feedback - use a set of fd instead of fds array - use global variables instead of maps (in v3, I mistakenly thought that the bpf maps are global variables.) - remove uncessary global variable path_info_index - remove fd compare as the fstat's order is fixed v2->v3: addressed Andrii's feedback - use global data instead of perf_buffer to simplified code v1->v2: addressed Daniel's feedback - rename bpf_fd2path to bpf_get_file_path to be consistent with other helper's names Signed-off-by: Wenbo Zhang <ethercflow@gmail.com> --- .../selftests/bpf/prog_tests/get_file_path.c | 173 ++++++++++++++++++ .../selftests/bpf/progs/test_get_file_path.c | 43 +++++ 2 files changed, 216 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/get_file_path.c create mode 100644 tools/testing/selftests/bpf/progs/test_get_file_path.c