tools/testing/selftests/proc/proc-pid-vm.c

   1 /*
   2  * Copyright (c) 2019 Alexey Dobriyan <adobriyan@gmail.com>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16 /*
  17  * Fork and exec tiny 1 page executable which precisely controls its VM.
  18  * Test /proc/$PID/maps
  19  * Test /proc/$PID/smaps
  20  * Test /proc/$PID/smaps_rollup
  21  * Test /proc/$PID/statm
  22  *
  23  * FIXME require CONFIG_TMPFS which can be disabled
  24  * FIXME test other values from "smaps"
  25  * FIXME support other archs
  26  */
  27 #undef NDEBUG
  28 #include <assert.h>
  29 #include <errno.h>
  30 #include <sched.h>
  31 #include <signal.h>
  32 #include <stdbool.h>
  33 #include <stdint.h>
  34 #include <stdio.h>
  35 #include <string.h>
  36 #include <stdlib.h>
  37 #include <sys/mount.h>
  38 #include <sys/types.h>
  39 #include <sys/stat.h>
  40 #include <sys/wait.h>
  41 #include <fcntl.h>
  42 #include <unistd.h>
  43 #include <sys/syscall.h>
  44 #include <sys/uio.h>
  45 #include <linux/kdev_t.h>
  46 #include <sys/time.h>
  47 #include <sys/resource.h>
  48
  49 static inline long sys_execveat(int dirfd, const char *pathname, char **argv, char **envp, int flags)
  50 {
  51         return syscall(SYS_execveat, dirfd, pathname, argv, envp, flags);
  52 }
  53
  54 static void make_private_tmp(void)
  55 {
  56         if (unshare(CLONE_NEWNS) == -1) {
  57                 if (errno == ENOSYS || errno == EPERM) {
  58                         exit(4);
  59                 }
  60                 exit(1);
  61         }
  62         if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
  63                 exit(1);
  64         }
  65         if (mount(NULL, "/tmp", "tmpfs", 0, NULL) == -1) {
  66                 exit(1);
  67         }
  68 }
  69
  70 static pid_t pid = -1;
  71 static void ate(void)
  72 {
  73         if (pid > 0) {
  74                 kill(pid, SIGTERM);
  75         }
  76 }
  77
  78 struct elf64_hdr {
  79         uint8_t e_ident[16];
  80         uint16_t e_type;
  81         uint16_t e_machine;
  82         uint32_t e_version;
  83         uint64_t e_entry;
  84         uint64_t e_phoff;
  85         uint64_t e_shoff;
  86         uint32_t e_flags;
  87         uint16_t e_ehsize;
  88         uint16_t e_phentsize;
  89         uint16_t e_phnum;
  90         uint16_t e_shentsize;
  91         uint16_t e_shnum;
  92         uint16_t e_shstrndx;
  93 };
  94
  95 struct elf64_phdr {
  96         uint32_t p_type;
  97         uint32_t p_flags;
  98         uint64_t p_offset;
  99         uint64_t p_vaddr;
 100         uint64_t p_paddr;
 101         uint64_t p_filesz;
 102         uint64_t p_memsz;
 103         uint64_t p_align;
 104 };
 105
 106 #ifdef __x86_64__
 107 #define PAGE_SIZE 4096
 108 #define VADDR (1UL << 32)
 109 #define MAPS_OFFSET 73
 110
 111 #define syscall 0x0f, 0x05
 112 #define mov_rdi(x)      \
 113         0x48, 0xbf,     \
 114         (x)&0xff, ((x)>>8)&0xff, ((x)>>16)&0xff, ((x)>>24)&0xff,        \
 115         ((x)>>32)&0xff, ((x)>>40)&0xff, ((x)>>48)&0xff, ((x)>>56)&0xff
 116
 117 #define mov_rsi(x)      \
 118         0x48, 0xbe,     \
 119         (x)&0xff, ((x)>>8)&0xff, ((x)>>16)&0xff, ((x)>>24)&0xff,        \
 120         ((x)>>32)&0xff, ((x)>>40)&0xff, ((x)>>48)&0xff, ((x)>>56)&0xff
 121
 122 #define mov_eax(x)      \
 123         0xb8, (x)&0xff, ((x)>>8)&0xff, ((x)>>16)&0xff, ((x)>>24)&0xff
 124
 125 static const uint8_t payload[] = {
 126         /* Casually unmap stack, vDSO and everything else. */
 127         /* munmap */
 128         mov_rdi(VADDR + 4096),
 129         mov_rsi((1ULL << 47) - 4096 - VADDR - 4096),
 130         mov_eax(11),
 131         syscall,
 132
 133         /* Ping parent. */
 134         /* write(0, &c, 1); */
 135         0x31, 0xff,                                     /* xor edi, edi */
 136         0x48, 0x8d, 0x35, 0x00, 0x00, 0x00, 0x00,       /* lea rsi, [rip] */
 137         0xba, 0x01, 0x00, 0x00, 0x00,                   /* mov edx, 1 */
 138         mov_eax(1),
 139         syscall,
 140
 141         /* 1: pause(); */
 142         mov_eax(34),
 143         syscall,
 144
 145         0xeb, 0xf7,     /* jmp 1b */
 146 };
 147
 148 static int make_exe(const uint8_t *payload, size_t len)
 149 {
 150         struct elf64_hdr h;
 151         struct elf64_phdr ph;
 152
 153         struct iovec iov[3] = {
 154                 {&h, sizeof(struct elf64_hdr)},
 155                 {&ph, sizeof(struct elf64_phdr)},
 156                 {(void *)payload, len},
 157         };
 158         int fd, fd1;
 159         char buf[64];
 160
 161         memset(&h, 0, sizeof(h));
 162         h.e_ident[0] = 0x7f;
 163         h.e_ident[1] = 'E';
 164         h.e_ident[2] = 'L';
 165         h.e_ident[3] = 'F';
 166         h.e_ident[4] = 2;
 167         h.e_ident[5] = 1;
 168         h.e_ident[6] = 1;
 169         h.e_ident[7] = 0;
 170         h.e_type = 2;
 171         h.e_machine = 0x3e;
 172         h.e_version = 1;
 173         h.e_entry = VADDR + sizeof(struct elf64_hdr) + sizeof(struct elf64_phdr);
 174         h.e_phoff = sizeof(struct elf64_hdr);
 175         h.e_shoff = 0;
 176         h.e_flags = 0;
 177         h.e_ehsize = sizeof(struct elf64_hdr);
 178         h.e_phentsize = sizeof(struct elf64_phdr);
 179         h.e_phnum = 1;
 180         h.e_shentsize = 0;
 181         h.e_shnum = 0;
 182         h.e_shstrndx = 0;
 183
 184         memset(&ph, 0, sizeof(ph));
 185         ph.p_type = 1;
 186         ph.p_flags = (1<<2)|1;
 187         ph.p_offset = 0;
 188         ph.p_vaddr = VADDR;
 189         ph.p_paddr = 0;
 190         ph.p_filesz = sizeof(struct elf64_hdr) + sizeof(struct elf64_phdr) + len;
 191         ph.p_memsz = sizeof(struct elf64_hdr) + sizeof(struct elf64_phdr) + len;
 192         ph.p_align = 4096;
 193
 194         fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_EXCL|O_TMPFILE, 0700);
 195         if (fd == -1) {
 196                 exit(1);
 197         }
 198
 199         if (writev(fd, iov, 3) != sizeof(struct elf64_hdr) + sizeof(struct elf64_phdr) + len) {
 200                 exit(1);
 201         }
 202
 203         /* Avoid ETXTBSY on exec. */
 204         snprintf(buf, sizeof(buf), "/proc/self/fd/%u", fd);
 205         fd1 = open(buf, O_RDONLY|O_CLOEXEC);
 206         close(fd);
 207
 208         return fd1;
 209 }
 210 #endif
 211
 212 static bool g_vsyscall = false;
 213
 214 static const char str_vsyscall[] =
 215 "ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]\n";
 216
 217 #ifdef __x86_64__
 218 static void sigaction_SIGSEGV(int _, siginfo_t *__, void *___)
 219 {
 220         _exit(1);
 221 }
 222
 223 /*
 224  * vsyscall page can't be unmapped, probe it with memory load.
 225  */
 226 static void vsyscall(void)
 227 {
 228         pid_t pid;
 229         int wstatus;
 230
 231         pid = fork();
 232         if (pid < 0) {
 233                 fprintf(stderr, "fork, errno %d\n", errno);
 234                 exit(1);
 235         }
 236         if (pid == 0) {
 237                 struct rlimit rlim = {0, 0};
 238                 (void)setrlimit(RLIMIT_CORE, &rlim);
 239
 240                 /* Hide "segfault at ffffffffff600000" messages. */
 241                 struct sigaction act;
 242                 memset(&act, 0, sizeof(struct sigaction));
 243                 act.sa_flags = SA_SIGINFO;
 244                 act.sa_sigaction = sigaction_SIGSEGV;
 245                 (void)sigaction(SIGSEGV, &act, NULL);
 246
 247                 *(volatile int *)0xffffffffff600000UL;
 248                 exit(0);
 249         }
 250         waitpid(pid, &wstatus, 0);
 251         if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) {
 252                 g_vsyscall = true;
 253         }
 254 }
 255
 256 int main(void)
 257 {
 258         int pipefd[2];
 259         int exec_fd;
 260
 261         vsyscall();
 262
 263         atexit(ate);
 264
 265         make_private_tmp();
 266
 267         /* Reserve fd 0 for 1-byte pipe ping from child. */
 268         close(0);
 269         if (open("/", O_RDONLY|O_DIRECTORY|O_PATH) != 0) {
 270                 return 1;
 271         }
 272
 273         exec_fd = make_exe(payload, sizeof(payload));
 274
 275         if (pipe(pipefd) == -1) {
 276                 return 1;
 277         }
 278         if (dup2(pipefd[1], 0) != 0) {
 279                 return 1;
 280         }
 281
 282         pid = fork();
 283         if (pid == -1) {
 284                 return 1;
 285         }
 286         if (pid == 0) {
 287                 sys_execveat(exec_fd, "", NULL, NULL, AT_EMPTY_PATH);
 288                 return 1;
 289         }
 290
 291         char _;
 292         if (read(pipefd[0], &_, 1) != 1) {
 293                 return 1;
 294         }
 295
 296         struct stat st;
 297         if (fstat(exec_fd, &st) == -1) {
 298                 return 1;
 299         }
 300
 301         /* Generate "head -n1 /proc/$PID/maps" */
 302         char buf0[256];
 303         memset(buf0, ' ', sizeof(buf0));
 304         int len = snprintf(buf0, sizeof(buf0),
 305                         "%08lx-%08lx r-xp 00000000 %02lx:%02lx %llu",
 306                         VADDR, VADDR + PAGE_SIZE,
 307                         MAJOR(st.st_dev), MINOR(st.st_dev),
 308                         (unsigned long long)st.st_ino);
 309         buf0[len] = ' ';
 310         snprintf(buf0 + MAPS_OFFSET, sizeof(buf0) - MAPS_OFFSET,
 311                  "/tmp/#%llu (deleted)\n", (unsigned long long)st.st_ino);
 312
 313         /* Test /proc/$PID/maps */
 314         {
 315                 const size_t len = strlen(buf0) + (g_vsyscall ? strlen(str_vsyscall) : 0);
 316                 char buf[256];
 317                 ssize_t rv;
 318                 int fd;
 319
 320                 snprintf(buf, sizeof(buf), "/proc/%u/maps", pid);
 321                 fd = open(buf, O_RDONLY);
 322                 if (fd == -1) {
 323                         return 1;
 324                 }
 325                 rv = read(fd, buf, sizeof(buf));
 326                 assert(rv == len);
 327                 assert(memcmp(buf, buf0, strlen(buf0)) == 0);
 328                 if (g_vsyscall) {
 329                         assert(memcmp(buf + strlen(buf0), str_vsyscall, strlen(str_vsyscall)) == 0);
 330                 }
 331         }
 332
 333         /* Test /proc/$PID/smaps */
 334         {
 335                 char buf[4096];
 336                 ssize_t rv;
 337                 int fd;
 338
 339                 snprintf(buf, sizeof(buf), "/proc/%u/smaps", pid);
 340                 fd = open(buf, O_RDONLY);
 341                 if (fd == -1) {
 342                         return 1;
 343                 }
 344                 rv = read(fd, buf, sizeof(buf));
 345                 assert(0 <= rv && rv <= sizeof(buf));
 346
 347                 assert(rv >= strlen(buf0));
 348                 assert(memcmp(buf, buf0, strlen(buf0)) == 0);
 349
 350 #define RSS1 "Rss:                   4 kB\n"
 351 #define RSS2 "Rss:                   0 kB\n"
 352 #define PSS1 "Pss:                   4 kB\n"
 353 #define PSS2 "Pss:                   0 kB\n"
 354                 assert(memmem(buf, rv, RSS1, strlen(RSS1)) ||
 355                        memmem(buf, rv, RSS2, strlen(RSS2)));
 356                 assert(memmem(buf, rv, PSS1, strlen(PSS1)) ||
 357                        memmem(buf, rv, PSS2, strlen(PSS2)));
 358
 359                 static const char *S[] = {
 360                         "Size:                  4 kB\n",
 361                         "KernelPageSize:        4 kB\n",
 362                         "MMUPageSize:           4 kB\n",
 363                         "Anonymous:             0 kB\n",
 364                         "AnonHugePages:         0 kB\n",
 365                         "Shared_Hugetlb:        0 kB\n",
 366                         "Private_Hugetlb:       0 kB\n",
 367                         "Locked:                0 kB\n",
 368                 };
 369                 int i;
 370
 371                 for (i = 0; i < sizeof(S)/sizeof(S[0]); i++) {
 372                         assert(memmem(buf, rv, S[i], strlen(S[i])));
 373                 }
 374
 375                 if (g_vsyscall) {
 376                         assert(memmem(buf, rv, str_vsyscall, strlen(str_vsyscall)));
 377                 }
 378         }
 379
 380         /* Test /proc/$PID/smaps_rollup */
 381         {
 382                 char bufr[256];
 383                 memset(bufr, ' ', sizeof(bufr));
 384                 len = snprintf(bufr, sizeof(bufr),
 385                                 "%08lx-%08lx ---p 00000000 00:00 0",
 386                                 VADDR, VADDR + PAGE_SIZE);
 387                 bufr[len] = ' ';
 388                 snprintf(bufr + MAPS_OFFSET, sizeof(bufr) - MAPS_OFFSET,
 389                          "[rollup]\n");
 390
 391                 char buf[1024];
 392                 ssize_t rv;
 393                 int fd;
 394
 395                 snprintf(buf, sizeof(buf), "/proc/%u/smaps_rollup", pid);
 396                 fd = open(buf, O_RDONLY);
 397                 if (fd == -1) {
 398                         return 1;
 399                 }
 400                 rv = read(fd, buf, sizeof(buf));
 401                 assert(0 <= rv && rv <= sizeof(buf));
 402
 403                 assert(rv >= strlen(bufr));
 404                 assert(memcmp(buf, bufr, strlen(bufr)) == 0);
 405
 406                 assert(memmem(buf, rv, RSS1, strlen(RSS1)) ||
 407                        memmem(buf, rv, RSS2, strlen(RSS2)));
 408                 assert(memmem(buf, rv, PSS1, strlen(PSS1)) ||
 409                        memmem(buf, rv, PSS2, strlen(PSS2)));
 410
 411                 static const char *S[] = {
 412                         "Anonymous:             0 kB\n",
 413                         "AnonHugePages:         0 kB\n",
 414                         "Shared_Hugetlb:        0 kB\n",
 415                         "Private_Hugetlb:       0 kB\n",
 416                         "Locked:                0 kB\n",
 417                 };
 418                 int i;
 419
 420                 for (i = 0; i < sizeof(S)/sizeof(S[0]); i++) {
 421                         assert(memmem(buf, rv, S[i], strlen(S[i])));
 422                 }
 423         }
 424
 425         /* Test /proc/$PID/statm */
 426         {
 427                 char buf[64];
 428                 ssize_t rv;
 429                 int fd;
 430
 431                 snprintf(buf, sizeof(buf), "/proc/%u/statm", pid);
 432                 fd = open(buf, O_RDONLY);
 433                 if (fd == -1) {
 434                         return 1;
 435                 }
 436                 rv = read(fd, buf, sizeof(buf));
 437                 assert(rv == 7 * 2);
 438
 439                 assert(buf[0] == '1');  /* ->total_vm */
 440                 assert(buf[1] == ' ');
 441                 assert(buf[2] == '0' || buf[2] == '1'); /* rss */
 442                 assert(buf[3] == ' ');
 443                 assert(buf[4] == '0' || buf[2] == '1'); /* file rss */
 444                 assert(buf[5] == ' ');
 445                 assert(buf[6] == '1');  /* ELF executable segments */
 446                 assert(buf[7] == ' ');
 447                 assert(buf[8] == '0');
 448                 assert(buf[9] == ' ');
 449                 assert(buf[10] == '0'); /* ->data_vm + ->stack_vm */
 450                 assert(buf[11] == ' ');
 451                 assert(buf[12] == '0');
 452                 assert(buf[13] == '\n');
 453         }
 454
 455         return 0;
 456 }
 457 #else
 458 int main(void)
 459 {
 460         return 4;
 461 }
 462 #endif