1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <errno.h>
18#include <fcntl.h>
19#include <getopt.h>
20#include <inttypes.h>
21#include <stdbool.h>
22#include <stdint.h>
23#include <stdlib.h>
24#include <string.h>
25#include <sys/types.h>
26#include <unistd.h>
27
28#include <pagemap/pagemap.h>
29
30#define MAX_FILENAME  64
31
32#define GROWTH_FACTOR 10
33
34#define NO_PATTERN    0x100
35
36#define PR_SORTED       1
37#define PR_VERBOSE      2
38#define PR_ALL          4
39
40struct vaddr {
41    unsigned long addr;
42    size_t num_pages;
43    pid_t pid;
44};
45
46struct ksm_page {
47    uint64_t count;
48    uint32_t hash;
49    struct vaddr *vaddr;
50    size_t vaddr_len, vaddr_size;
51    size_t vaddr_count;
52    uint16_t pattern;
53};
54
55struct ksm_pages {
56    struct ksm_page *pages;
57    size_t len, size;
58};
59
60static void usage(char *myname);
61static int getprocname(pid_t pid, char *buf, int len);
62static int read_pages(struct ksm_pages *kp, pm_map_t **maps, size_t num_maps, uint8_t pr_flags);
63static void print_pages(struct ksm_pages *kp, uint8_t pr_flags);
64static void free_pages(struct ksm_pages *kp, uint8_t pr_flags);
65static bool is_pattern(uint8_t *data, size_t len);
66static int cmp_pages(const void *a, const void *b);
67extern uint32_t hashword(const uint32_t *, size_t, int32_t);
68
69int main(int argc, char *argv[]) {
70    pm_kernel_t *ker;
71    pm_process_t *proc;
72    pid_t *pids;
73    size_t num_procs;
74    size_t i;
75    pm_map_t **maps;
76    size_t num_maps;
77    char cmdline[256]; // this must be within the range of int
78    int error;
79    int rc = EXIT_SUCCESS;
80    uint8_t pr_flags = 0;
81    struct ksm_pages kp;
82
83    memset(&kp, 0, sizeof(kp));
84
85    opterr = 0;
86    do {
87        int c = getopt(argc, argv, "hvsa");
88        if (c == -1)
89            break;
90
91        switch (c) {
92            case 'a':
93                pr_flags |= PR_ALL;
94                break;
95            case 's':
96                pr_flags |= PR_SORTED;
97                break;
98            case 'v':
99                pr_flags |= PR_VERBOSE;
100                break;
101            case 'h':
102                usage(argv[0]);
103                exit(EXIT_SUCCESS);
104            case '?':
105                fprintf(stderr, "unknown option: %c\n", optopt);
106                usage(argv[0]);
107                exit(EXIT_FAILURE);
108        }
109    } while (1);
110
111    error = pm_kernel_create(&ker);
112    if (error) {
113        fprintf(stderr, "Error creating kernel interface -- "
114                        "does this kernel have pagemap?\n");
115        exit(EXIT_FAILURE);
116    }
117
118    if (pr_flags & PR_ALL) {
119        error = pm_kernel_pids(ker, &pids, &num_procs);
120        if (error) {
121            fprintf(stderr, "Error listing processes.\n");
122            exit(EXIT_FAILURE);
123        }
124    } else {
125        if (optind != argc - 1) {
126            usage(argv[0]);
127            exit(EXIT_FAILURE);
128        }
129
130        pids = malloc(sizeof(*pids));
131        if (pids == NULL) {
132           fprintf(stderr, "Error allocating pid memory\n");
133           exit(EXIT_FAILURE);
134        }
135
136        *pids = strtoul(argv[optind], NULL, 10);
137        if (*pids == 0) {
138            fprintf(stderr, "Invalid PID\n");
139            rc = EXIT_FAILURE;
140            goto exit;
141        }
142        num_procs = 1;
143        if (getprocname(*pids, cmdline, sizeof(cmdline)) < 0) {
144            cmdline[0] = '\0';
145        }
146        printf("%s (%u):\n", cmdline, *pids);
147    }
148
149    printf("Warning: this tool only compares the KSM CRCs of pages, there is a chance of "
150            "collisions\n");
151
152    for (i = 0; i < num_procs; i++) {
153        error = pm_process_create(ker, pids[i], &proc);
154        if (error) {
155            fprintf(stderr, "warning: could not create process interface for %d\n", pids[i]);
156            rc = EXIT_FAILURE;
157            goto exit;
158        }
159
160        error = pm_process_maps(proc, &maps, &num_maps);
161        if (error) {
162            pm_process_destroy(proc);
163            fprintf(stderr, "warning: could not read process map for %d\n", pids[i]);
164            rc = EXIT_FAILURE;
165            goto exit;
166        }
167
168        if (read_pages(&kp, maps, num_maps, pr_flags) < 0) {
169            free(maps);
170            pm_process_destroy(proc);
171            rc = EXIT_FAILURE;
172            goto exit;
173        }
174
175        free(maps);
176        pm_process_destroy(proc);
177    }
178
179    if (pr_flags & PR_SORTED) {
180        qsort(kp.pages, kp.len, sizeof(*kp.pages), cmp_pages);
181    }
182    print_pages(&kp, pr_flags);
183
184exit:
185    free_pages(&kp, pr_flags);
186    free(pids);
187    return rc;
188}
189
190static int read_pages(struct ksm_pages *kp, pm_map_t **maps, size_t num_maps, uint8_t pr_flags) {
191    size_t i, j, k;
192    uint64_t *pagemap;
193    size_t map_len;
194    uint64_t flags;
195    pm_kernel_t *ker;
196    int error;
197    unsigned long vaddr;
198    int fd;
199    off_t off;
200    char filename[MAX_FILENAME];
201    uint32_t *data;
202    uint32_t hash;
203    int rc = 0;
204    struct ksm_page *cur_page;
205    pid_t pid;
206
207    if (num_maps == 0)
208        return 0;
209
210    pid = pm_process_pid(maps[0]->proc);
211    ker = maps[0]->proc->ker;
212    error = snprintf(filename, MAX_FILENAME, "/proc/%d/mem", pid);
213    if (error < 0 || error >= MAX_FILENAME) {
214        return -1;
215    }
216
217    data = malloc(pm_kernel_pagesize(ker));
218    if (data == NULL) {
219        fprintf(stderr, "warning: not enough memory to malloc data buffer\n");
220        return -1;
221    }
222
223    fd = open(filename, O_RDONLY);
224    if (fd < 0) {
225        fprintf(stderr, "warning: could not open %s\n", filename);
226        rc = -1;
227        goto err_open;
228    }
229
230    for (i = 0; i < num_maps; i++) {
231        error = pm_map_pagemap(maps[i], &pagemap, &map_len);
232        if (error) {
233            fprintf(stderr, "warning: could not read the pagemap of %d\n",
234                    pm_process_pid(maps[i]->proc));
235            continue;
236        }
237        for (j = 0; j < map_len; j++) {
238            error = pm_kernel_flags(ker, PM_PAGEMAP_PFN(pagemap[j]), &flags);
239            if (error) {
240                fprintf(stderr, "warning: could not read flags for pfn at address 0x%016" PRIx64 "\n",
241                        pagemap[i]);
242                continue;
243            }
244            if (!(flags & PM_PAGE_KSM)) {
245                continue;
246            }
247            vaddr = pm_map_start(maps[i]) + j * pm_kernel_pagesize(ker);
248            off = lseek(fd, vaddr, SEEK_SET);
249            if (off == (off_t)-1) {
250                fprintf(stderr, "warning: could not lseek to 0x%08lx\n", vaddr);
251                continue;
252            }
253            ssize_t len = read(fd, data, pm_kernel_pagesize(ker));
254            if (len != pm_kernel_pagesize(ker)) {
255                fprintf(stderr, "warning: could not read page at 0x%08lx\n", vaddr);
256                continue;
257            }
258
259            hash = hashword(data, pm_kernel_pagesize(ker) / sizeof(*data), 17);
260
261            for (k = 0; k < kp->len; k++) {
262                if (kp->pages[k].hash == hash) break;
263            }
264
265            if (k == kp->len) {
266                if (kp->len == kp->size) {
267                    struct ksm_page *tmp = realloc(kp->pages,
268                            (kp->size + GROWTH_FACTOR) * sizeof(*kp->pages));
269                    if (tmp == NULL) {
270                        fprintf(stderr, "warning: not enough memory to realloc pages struct\n");
271                        free(pagemap);
272                        rc = -1;
273                        goto err_realloc;
274                    }
275                    memset(&tmp[k], 0, sizeof(tmp[k]) * GROWTH_FACTOR);
276                    kp->pages = tmp;
277                    kp->size += GROWTH_FACTOR;
278                }
279                rc = pm_kernel_count(ker, PM_PAGEMAP_PFN(pagemap[j]), &kp->pages[kp->len].count);
280                if (rc) {
281                    fprintf(stderr, "error reading page count\n");
282                    free(pagemap);
283                    goto err_count;
284                }
285                kp->pages[kp->len].hash = hash;
286                kp->pages[kp->len].pattern =
287                        is_pattern((uint8_t *)data, pm_kernel_pagesize(ker)) ?
288                        (data[0] & 0xFF) : NO_PATTERN;
289                kp->len++;
290            }
291
292            cur_page = &kp->pages[k];
293
294            if (pr_flags & PR_VERBOSE) {
295                if (cur_page->vaddr_len > 0 &&
296                        cur_page->vaddr[cur_page->vaddr_len - 1].pid == pid &&
297                        cur_page->vaddr[cur_page->vaddr_len - 1].addr ==
298                        vaddr - (cur_page->vaddr[cur_page->vaddr_len - 1].num_pages *
299                        pm_kernel_pagesize(ker))) {
300                    cur_page->vaddr[cur_page->vaddr_len - 1].num_pages++;
301                } else {
302                    if (cur_page->vaddr_len == cur_page->vaddr_size) {
303                        struct vaddr *tmp = realloc(cur_page->vaddr,
304                                (cur_page->vaddr_size + GROWTH_FACTOR) * sizeof(*(cur_page->vaddr)));
305                        if (tmp == NULL) {
306                            fprintf(stderr, "warning: not enough memory to realloc vaddr array\n");
307                            free(pagemap);
308                            rc = -1;
309                            goto err_realloc;
310                        }
311                        memset(&tmp[cur_page->vaddr_len], 0, sizeof(tmp[cur_page->vaddr_len]) * GROWTH_FACTOR);
312                        cur_page->vaddr = tmp;
313                        cur_page->vaddr_size += GROWTH_FACTOR;
314                    }
315                    cur_page->vaddr[cur_page->vaddr_len].addr = vaddr;
316                    cur_page->vaddr[cur_page->vaddr_len].num_pages = 1;
317                    cur_page->vaddr[cur_page->vaddr_len].pid = pid;
318                    cur_page->vaddr_len++;
319                }
320            }
321            cur_page->vaddr_count++;
322        }
323        free(pagemap);
324    }
325    goto no_err;
326
327err_realloc:
328err_count:
329    if (pr_flags & PR_VERBOSE) {
330        for (i = 0; i < kp->len; i++) {
331            free(kp->pages[i].vaddr);
332        }
333    }
334    free(kp->pages);
335
336no_err:
337    close(fd);
338err_open:
339    free(data);
340    return rc;
341}
342
343static void print_pages(struct ksm_pages *kp, uint8_t pr_flags) {
344    size_t i, j, k;
345    char suffix[13];
346    int index;
347
348    for (i = 0; i < kp->len; i++) {
349        if (kp->pages[i].pattern != NO_PATTERN) {
350            printf("0x%02x byte pattern: ", kp->pages[i].pattern);
351        } else {
352            printf("KSM CRC 0x%08x:", kp->pages[i].hash);
353        }
354        printf(" %4zu page", kp->pages[i].vaddr_count);
355        if (kp->pages[i].vaddr_count > 1) {
356            printf("s");
357        }
358        if (!(pr_flags & PR_ALL)) {
359            printf(" (%" PRIu64 " reference", kp->pages[i].count);
360            if (kp->pages[i].count > 1) {
361                printf("s");
362            }
363            printf(")");
364        }
365        printf("\n");
366
367        if (pr_flags & PR_VERBOSE) {
368            j = 0;
369            while (j < kp->pages[i].vaddr_len) {
370                printf("                   ");
371                for (k = 0; k < 8 && j < kp->pages[i].vaddr_len; k++, j++) {
372                    printf(" 0x%08lx", kp->pages[i].vaddr[j].addr);
373
374                    index = snprintf(suffix, sizeof(suffix), ":%zu",
375                            kp->pages[i].vaddr[j].num_pages);
376                    if (pr_flags & PR_ALL) {
377                        index += snprintf(suffix + index, sizeof(suffix) - index, "[%d]",
378                                kp->pages[i].vaddr[j].pid);
379                    }
380                    printf("%-12s", suffix);
381                }
382                printf("\n");
383            }
384        }
385    }
386}
387
388static void free_pages(struct ksm_pages *kp, uint8_t pr_flags) {
389    size_t i;
390
391    if (pr_flags & PR_VERBOSE) {
392        for (i = 0; i < kp->len; i++) {
393            free(kp->pages[i].vaddr);
394        }
395    }
396    free(kp->pages);
397}
398
399static void usage(char *myname) {
400    fprintf(stderr, "Usage: %s [-s | -v | -a | -h ] <pid>\n"
401                    "    -s  Sort pages by usage count.\n"
402                    "    -v  Verbose: print virtual addresses.\n"
403                    "    -a  Display all the KSM pages in the system. Ignore the pid argument.\n"
404                    "    -h  Display this help screen.\n",
405    myname);
406}
407
408static int cmp_pages(const void *a, const void *b) {
409    const struct ksm_page *pg_a = a;
410    const struct ksm_page *pg_b = b;
411    int cmp = pg_b->vaddr_count - pg_a->vaddr_count;
412
413    return cmp ? cmp : pg_b->count - pg_a->count;
414}
415
416static bool is_pattern(uint8_t *data, size_t len) {
417    size_t i;
418    uint8_t first_byte = data[0];
419
420    for (i = 1; i < len; i++) {
421        if (first_byte != data[i]) return false;
422    }
423
424    return true;
425}
426
427/*
428 * Get the process name for a given PID. Inserts the process name into buffer
429 * buf of length len. The size of the buffer must be greater than zero to get
430 * any useful output.
431 *
432 * Note that fgets(3) only declares length as an int, so our buffer size is
433 * also declared as an int.
434 *
435 * Returns 0 on success, a positive value on partial success, and -1 on
436 * failure. Other interesting values:
437 *   1 on failure to create string to examine proc cmdline entry
438 *   2 on failure to open proc cmdline entry
439 *   3 on failure to read proc cmdline entry
440 */
441static int getprocname(pid_t pid, char *buf, int len) {
442    char *filename;
443    FILE *f;
444    int rc = 0;
445    static const char* unknown_cmdline = "<unknown>";
446
447    if (len <= 0) {
448        return -1;
449    }
450
451    if (asprintf(&filename, "/proc/%d/cmdline", (int)pid) < 0) {
452        rc = 1;
453        goto exit;
454    }
455
456    f = fopen(filename, "r");
457    if (f == NULL) {
458        rc = 2;
459        goto releasefilename;
460    }
461
462    if (fgets(buf, len, f) == NULL) {
463        rc = 3;
464        goto closefile;
465    }
466
467closefile:
468    (void) fclose(f);
469releasefilename:
470    free(filename);
471exit:
472    if (rc != 0) {
473        /*
474         * The process went away before we could read its process name. Try
475         * to give the user "<unknown>" here, but otherwise they get to look
476         * at a blank.
477         */
478        if (strlcpy(buf, unknown_cmdline, (size_t)len) >= (size_t)len) {
479            rc = 4;
480        }
481    }
482
483    return rc;
484}
485
486