| Message ID | 20210204205002.4075937-5-songliubraving@fb.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | introduce bpf_iter for task_vma | expand |
On 2/4/21 12:50 PM, Song Liu wrote: > The test dumps information similar to /proc/pid/maps. The first line of > the output is compared against the /proc file to make sure they match. > > Signed-off-by: Song Liu <songliubraving@fb.com> > --- > .../selftests/bpf/prog_tests/bpf_iter.c | 114 ++++++++++++++++-- > tools/testing/selftests/bpf/progs/bpf_iter.h | 8 ++ > .../selftests/bpf/progs/bpf_iter_task_vma.c | 58 +++++++++ > 3 files changed, 170 insertions(+), 10 deletions(-) > create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c > index 0e586368948dd..9e8027685e859 100644 > --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c > +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c > @@ -7,6 +7,7 @@ > #include "bpf_iter_task.skel.h" > #include "bpf_iter_task_stack.skel.h" > #include "bpf_iter_task_file.skel.h" > +#include "bpf_iter_task_vma.skel.h" > #include "bpf_iter_task_btf.skel.h" > #include "bpf_iter_tcp4.skel.h" > #include "bpf_iter_tcp6.skel.h" > @@ -64,6 +65,22 @@ static void do_dummy_read(struct bpf_program *prog) > bpf_link__destroy(link); > } > > +static int read_fd_into_buffer(int fd, char *buf, int size) > +{ > + int bufleft = size; > + int len; > + > + do { > + len = read(fd, buf, bufleft); > + if (len > 0) { > + buf += len; > + bufleft -= len; > + } > + } while (len > 0); > + > + return len < 0 ? len : size - bufleft; > +} > + > static void test_ipv6_route(void) > { > struct bpf_iter_ipv6_route *skel; > @@ -177,7 +194,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel) > { > struct bpf_program *prog = skel->progs.dump_task_struct; > struct bpf_iter_task_btf__bss *bss = skel->bss; > - int iter_fd = -1, len = 0, bufleft = TASKBUFSZ; > + int iter_fd = -1, err; > struct bpf_link *link; > char *buf = taskbuf; > int ret = 0; > @@ -190,14 +207,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel) > if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n")) > goto free_link; > > - do { > - len = read(iter_fd, buf, bufleft); > - if (len > 0) { > - buf += len; > - bufleft -= len; > - } > - } while (len > 0); > - > + err = read_fd_into_buffer(iter_fd, buf, TASKBUFSZ); > if (bss->skip) { > printf("%s:SKIP:no __builtin_btf_type_id\n", __func__); > ret = 1; > @@ -205,7 +215,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel) > goto free_link; > } > > - if (CHECK(len < 0, "read", "read failed: %s\n", strerror(errno))) > + if (CHECK(err < 0, "read", "read failed: %s\n", strerror(errno))) > goto free_link; > > CHECK(strstr(taskbuf, "(struct task_struct)") == NULL, > @@ -1133,6 +1143,88 @@ static void test_buf_neg_offset(void) > bpf_iter_test_kern6__destroy(skel); > } > > +#define CMP_BUFFER_SIZE 1024 > +static char task_vma_output[CMP_BUFFER_SIZE]; > +static char proc_maps_output[CMP_BUFFER_SIZE]; > + > +/* remove \0 and \t from str, and only keep the first line */ > +static void str_strip_first_line(char *str) > +{ > + char *dst = str, *src = str; > + > + do { > + if (*src == ' ' || *src == '\t') > + src++; > + else > + *(dst++) = *(src++); > + > + } while (*src != '\0' && *src != '\n'); > + > + *dst = '\0'; > +} > + > +#define min(a, b) ((a) < (b) ? (a) : (b)) > + > +static void test_task_vma(void) > +{ > + int err, iter_fd = -1, proc_maps_fd = -1; > + struct bpf_iter_task_vma *skel; > + int len, read_size = 4; > + char maps_path[64]; > + > + skel = bpf_iter_task_vma__open(); > + if (CHECK(!skel, "bpf_iter_task_vma__open", "skeleton open failed\n")) > + return; > + > + skel->bss->pid = getpid(); > + > + err = bpf_iter_task_vma__load(skel); > + if (CHECK(err, "bpf_iter_task_vma__load", "skeleton load failed\n")) > + goto out; > + > + skel->links.proc_maps = bpf_program__attach_iter( > + skel->progs.proc_maps, NULL); > + > + if (CHECK(IS_ERR(skel->links.proc_maps), "bpf_program__attach_iter", > + "attach iterator failed\n")) > + goto out; You need to set skel->links.proc_maps = NULL before goto out. Otherwise, libbpf may segfault. > + > + /* read CMP_BUFFER_SIZE (1kB) from bpf_iter */ This comment better right before /* read in small chunks to trigger seq_file corner cases */ > + iter_fd = bpf_iter_create(bpf_link__fd(skel->links.proc_maps)); > + if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n")) > + goto out; > + > + /* read in small chunks to trigger seq_file corner cases */ > + len = 0; > + while (len < CMP_BUFFER_SIZE) { Some comment will be better to assure that we won't trigger infinite loop here, e.g., err == 0 case. > + err = read_fd_into_buffer(iter_fd, task_vma_output + len, > + min(read_size, CMP_BUFFER_SIZE - len)); > + if (CHECK(err < 0, "read_iter_fd", "read_iter_fd failed\n")) > + goto out; > + len += err; > + } > + > + /* read CMP_BUFFER_SIZE (1kB) from /proc/pid/maps */ > + snprintf(maps_path, 64, "/proc/%u/maps", skel->bss->pid); > + proc_maps_fd = open(maps_path, O_RDONLY); > + if (CHECK(proc_maps_fd < 0, "open_proc_maps", "open_proc_maps failed\n")) > + goto out; > + err = read_fd_into_buffer(proc_maps_fd, proc_maps_output, CMP_BUFFER_SIZE); > + if (CHECK(err < 0, "read_prog_maps_fd", "read_prog_maps_fd failed\n")) > + goto out; > + > + /* strip and compare the first line of the two files */ > + str_strip_first_line(task_vma_output); > + str_strip_first_line(proc_maps_output); > + > + CHECK(strcmp(task_vma_output, proc_maps_output), "compare_output", > + "found mismatch\n"); > +out: > + close(proc_maps_fd); > + close(iter_fd); > + bpf_iter_task_vma__destroy(skel); > +} > + > void test_bpf_iter(void) > { > if (test__start_subtest("btf_id_or_null")) > @@ -1149,6 +1241,8 @@ void test_bpf_iter(void) > test_task_stack(); > if (test__start_subtest("task_file")) > test_task_file(); > + if (test__start_subtest("task_vma")) > + test_task_vma(); > if (test__start_subtest("task_btf")) > test_task_btf(); > if (test__start_subtest("tcp4")) > diff --git a/tools/testing/selftests/bpf/progs/bpf_iter.h b/tools/testing/selftests/bpf/progs/bpf_iter.h > index 6a1255465fd6d..3d83b185c4bcb 100644 > --- a/tools/testing/selftests/bpf/progs/bpf_iter.h > +++ b/tools/testing/selftests/bpf/progs/bpf_iter.h [...]
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c index 0e586368948dd..9e8027685e859 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c @@ -7,6 +7,7 @@ #include "bpf_iter_task.skel.h" #include "bpf_iter_task_stack.skel.h" #include "bpf_iter_task_file.skel.h" +#include "bpf_iter_task_vma.skel.h" #include "bpf_iter_task_btf.skel.h" #include "bpf_iter_tcp4.skel.h" #include "bpf_iter_tcp6.skel.h" @@ -64,6 +65,22 @@ static void do_dummy_read(struct bpf_program *prog) bpf_link__destroy(link); } +static int read_fd_into_buffer(int fd, char *buf, int size) +{ + int bufleft = size; + int len; + + do { + len = read(fd, buf, bufleft); + if (len > 0) { + buf += len; + bufleft -= len; + } + } while (len > 0); + + return len < 0 ? len : size - bufleft; +} + static void test_ipv6_route(void) { struct bpf_iter_ipv6_route *skel; @@ -177,7 +194,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel) { struct bpf_program *prog = skel->progs.dump_task_struct; struct bpf_iter_task_btf__bss *bss = skel->bss; - int iter_fd = -1, len = 0, bufleft = TASKBUFSZ; + int iter_fd = -1, err; struct bpf_link *link; char *buf = taskbuf; int ret = 0; @@ -190,14 +207,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel) if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n")) goto free_link; - do { - len = read(iter_fd, buf, bufleft); - if (len > 0) { - buf += len; - bufleft -= len; - } - } while (len > 0); - + err = read_fd_into_buffer(iter_fd, buf, TASKBUFSZ); if (bss->skip) { printf("%s:SKIP:no __builtin_btf_type_id\n", __func__); ret = 1; @@ -205,7 +215,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel) goto free_link; } - if (CHECK(len < 0, "read", "read failed: %s\n", strerror(errno))) + if (CHECK(err < 0, "read", "read failed: %s\n", strerror(errno))) goto free_link; CHECK(strstr(taskbuf, "(struct task_struct)") == NULL, @@ -1133,6 +1143,88 @@ static void test_buf_neg_offset(void) bpf_iter_test_kern6__destroy(skel); } +#define CMP_BUFFER_SIZE 1024 +static char task_vma_output[CMP_BUFFER_SIZE]; +static char proc_maps_output[CMP_BUFFER_SIZE]; + +/* remove \0 and \t from str, and only keep the first line */ +static void str_strip_first_line(char *str) +{ + char *dst = str, *src = str; + + do { + if (*src == ' ' || *src == '\t') + src++; + else + *(dst++) = *(src++); + + } while (*src != '\0' && *src != '\n'); + + *dst = '\0'; +} + +#define min(a, b) ((a) < (b) ? (a) : (b)) + +static void test_task_vma(void) +{ + int err, iter_fd = -1, proc_maps_fd = -1; + struct bpf_iter_task_vma *skel; + int len, read_size = 4; + char maps_path[64]; + + skel = bpf_iter_task_vma__open(); + if (CHECK(!skel, "bpf_iter_task_vma__open", "skeleton open failed\n")) + return; + + skel->bss->pid = getpid(); + + err = bpf_iter_task_vma__load(skel); + if (CHECK(err, "bpf_iter_task_vma__load", "skeleton load failed\n")) + goto out; + + skel->links.proc_maps = bpf_program__attach_iter( + skel->progs.proc_maps, NULL); + + if (CHECK(IS_ERR(skel->links.proc_maps), "bpf_program__attach_iter", + "attach iterator failed\n")) + goto out; + + /* read CMP_BUFFER_SIZE (1kB) from bpf_iter */ + iter_fd = bpf_iter_create(bpf_link__fd(skel->links.proc_maps)); + if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n")) + goto out; + + /* read in small chunks to trigger seq_file corner cases */ + len = 0; + while (len < CMP_BUFFER_SIZE) { + err = read_fd_into_buffer(iter_fd, task_vma_output + len, + min(read_size, CMP_BUFFER_SIZE - len)); + if (CHECK(err < 0, "read_iter_fd", "read_iter_fd failed\n")) + goto out; + len += err; + } + + /* read CMP_BUFFER_SIZE (1kB) from /proc/pid/maps */ + snprintf(maps_path, 64, "/proc/%u/maps", skel->bss->pid); + proc_maps_fd = open(maps_path, O_RDONLY); + if (CHECK(proc_maps_fd < 0, "open_proc_maps", "open_proc_maps failed\n")) + goto out; + err = read_fd_into_buffer(proc_maps_fd, proc_maps_output, CMP_BUFFER_SIZE); + if (CHECK(err < 0, "read_prog_maps_fd", "read_prog_maps_fd failed\n")) + goto out; + + /* strip and compare the first line of the two files */ + str_strip_first_line(task_vma_output); + str_strip_first_line(proc_maps_output); + + CHECK(strcmp(task_vma_output, proc_maps_output), "compare_output", + "found mismatch\n"); +out: + close(proc_maps_fd); + close(iter_fd); + bpf_iter_task_vma__destroy(skel); +} + void test_bpf_iter(void) { if (test__start_subtest("btf_id_or_null")) @@ -1149,6 +1241,8 @@ void test_bpf_iter(void) test_task_stack(); if (test__start_subtest("task_file")) test_task_file(); + if (test__start_subtest("task_vma")) + test_task_vma(); if (test__start_subtest("task_btf")) test_task_btf(); if (test__start_subtest("tcp4")) diff --git a/tools/testing/selftests/bpf/progs/bpf_iter.h b/tools/testing/selftests/bpf/progs/bpf_iter.h index 6a1255465fd6d..3d83b185c4bcb 100644 --- a/tools/testing/selftests/bpf/progs/bpf_iter.h +++ b/tools/testing/selftests/bpf/progs/bpf_iter.h @@ -7,6 +7,7 @@ #define bpf_iter__netlink bpf_iter__netlink___not_used #define bpf_iter__task bpf_iter__task___not_used #define bpf_iter__task_file bpf_iter__task_file___not_used +#define bpf_iter__task_vma bpf_iter__task_vma___not_used #define bpf_iter__tcp bpf_iter__tcp___not_used #define tcp6_sock tcp6_sock___not_used #define bpf_iter__udp bpf_iter__udp___not_used @@ -26,6 +27,7 @@ #undef bpf_iter__netlink #undef bpf_iter__task #undef bpf_iter__task_file +#undef bpf_iter__task_vma #undef bpf_iter__tcp #undef tcp6_sock #undef bpf_iter__udp @@ -67,6 +69,12 @@ struct bpf_iter__task_file { struct file *file; } __attribute__((preserve_access_index)); +struct bpf_iter__task_vma { + struct bpf_iter_meta *meta; + struct task_struct *task; + struct vm_area_struct *vma; +} __attribute__((preserve_access_index)); + struct bpf_iter__bpf_map { struct bpf_iter_meta *meta; struct bpf_map *map; diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c new file mode 100644 index 0000000000000..d789e32cdb16c --- /dev/null +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Facebook */ +#include "bpf_iter.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +/* Copied from mm.h */ +#define VM_READ 0x00000001 +#define VM_WRITE 0x00000002 +#define VM_EXEC 0x00000004 +#define VM_MAYSHARE 0x00000080 + +/* Copied from kdev_t.h */ +#define MINORBITS 20 +#define MINORMASK ((1U << MINORBITS) - 1) +#define MAJOR(dev) ((unsigned int) ((dev) >> MINORBITS)) +#define MINOR(dev) ((unsigned int) ((dev) & MINORMASK)) + +#define D_PATH_BUF_SIZE 1024 +char d_path_buf[D_PATH_BUF_SIZE] = {}; +__u32 pid = 0; + +SEC("iter.s/task_vma") int proc_maps(struct bpf_iter__task_vma *ctx) +{ + struct vm_area_struct *vma = ctx->vma; + struct seq_file *seq = ctx->meta->seq; + struct task_struct *task = ctx->task; + struct file *file; + char perm_str[] = "----"; + + if (task == (void *)0 || vma == (void *)0) + return 0; + + file = vma->vm_file; + if (task->tgid != pid) + return 0; + perm_str[0] = (vma->vm_flags & VM_READ) ? 'r' : '-'; + perm_str[1] = (vma->vm_flags & VM_WRITE) ? 'w' : '-'; + perm_str[2] = (vma->vm_flags & VM_EXEC) ? 'x' : '-'; + perm_str[3] = (vma->vm_flags & VM_MAYSHARE) ? 's' : 'p'; + BPF_SEQ_PRINTF(seq, "%08llx-%08llx %s ", vma->vm_start, vma->vm_end, perm_str); + + if (file) { + __u32 dev = file->f_inode->i_sb->s_dev; + + bpf_d_path(&file->f_path, d_path_buf, D_PATH_BUF_SIZE); + + BPF_SEQ_PRINTF(seq, "%08llx ", vma->vm_pgoff << 12); + BPF_SEQ_PRINTF(seq, "%02x:%02x %u", MAJOR(dev), MINOR(dev), + file->f_inode->i_ino); + BPF_SEQ_PRINTF(seq, "\t%s\n", d_path_buf); + } else { + BPF_SEQ_PRINTF(seq, "%08llx 00:00 0\n", 0ULL); + } + return 0; +}
The test dumps information similar to /proc/pid/maps. The first line of the output is compared against the /proc file to make sure they match. Signed-off-by: Song Liu <songliubraving@fb.com> --- .../selftests/bpf/prog_tests/bpf_iter.c | 114 ++++++++++++++++-- tools/testing/selftests/bpf/progs/bpf_iter.h | 8 ++ .../selftests/bpf/progs/bpf_iter_task_vma.c | 58 +++++++++ 3 files changed, 170 insertions(+), 10 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c