pm_kernel.c revision e16cb84e2324f05334d18dcf5956f20f44262b62
1/*
2 * Copyright (C) 2008 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 <dirent.h>
18#include <errno.h>
19#include <fcntl.h>
20#include <stdint.h>
21#include <stdlib.h>
22#include <sys/stat.h>
23#include <sys/types.h>
24#include <unistd.h>
25
26#include <pagemap/pagemap.h>
27
28int pm_kernel_create(pm_kernel_t **ker_out) {
29    pm_kernel_t *ker;
30    int error;
31
32    if (!ker_out)
33        return 1;
34
35    ker = calloc(1, sizeof(*ker));
36    if (!ker)
37        return errno;
38
39    ker->kpagecount_fd = open("/proc/kpagecount", O_RDONLY);
40    if (ker->kpagecount_fd < 0) {
41        error = errno;
42        free(ker);
43        return error;
44    }
45
46    ker->kpageflags_fd = open("/proc/kpageflags", O_RDONLY);
47    if (ker->kpageflags_fd < 0) {
48        error = errno;
49        close(ker->kpagecount_fd);
50        free(ker);
51        return error;
52    }
53
54    ker->pagesize = getpagesize();
55
56    *ker_out = ker;
57
58    return 0;
59}
60
61#define INIT_PIDS 20
62int pm_kernel_pids(pm_kernel_t *ker, pid_t **pids_out, size_t *len) {
63    DIR *proc;
64    struct dirent *dir;
65    pid_t pid, *pids, *new_pids;
66    size_t pids_count, pids_size;
67    int error;
68
69    proc = opendir("/proc");
70    if (!proc)
71        return errno;
72
73    pids = malloc(INIT_PIDS * sizeof(pid_t));
74    if (!pids) {
75        closedir(proc);
76        return errno;
77    }
78    pids_count = 0; pids_size = INIT_PIDS;
79
80    while ((dir = readdir(proc))) {
81        if (sscanf(dir->d_name, "%d", &pid) < 1)
82            continue;
83
84        if (pids_count >= pids_size) {
85            new_pids = realloc(pids, 2 * pids_size * sizeof(pid_t));
86            if (!new_pids) {
87                error = errno;
88                free(pids);
89                closedir(proc);
90                return error;
91            }
92            pids = new_pids;
93            pids_size = 2 * pids_size;
94        }
95
96        pids[pids_count] = pid;
97
98        pids_count++;
99    }
100
101    closedir(proc);
102
103    new_pids = realloc(pids, pids_count * sizeof(pid_t));
104    if (!new_pids) {
105        error = errno;
106        free(pids);
107        return error;
108    }
109
110    *pids_out = new_pids;
111    *len = pids_count;
112
113    return 0;
114}
115
116int pm_kernel_count(pm_kernel_t *ker, unsigned long pfn, uint64_t *count_out) {
117    off_t off;
118
119    if (!ker || !count_out)
120        return -1;
121
122    off = lseek(ker->kpagecount_fd, pfn * sizeof(uint64_t), SEEK_SET);
123    if (off == (off_t)-1)
124        return errno;
125    if (read(ker->kpagecount_fd, count_out, sizeof(uint64_t)) <
126        (ssize_t)sizeof(uint64_t))
127        return errno;
128
129    return 0;
130}
131
132int pm_kernel_flags(pm_kernel_t *ker, unsigned long pfn, uint64_t *flags_out) {
133    off_t off;
134
135    if (!ker || !flags_out)
136        return -1;
137
138    off = lseek(ker->kpageflags_fd, pfn * sizeof(uint64_t), SEEK_SET);
139    if (off == (off_t)-1)
140        return errno;
141    if (read(ker->kpageflags_fd, flags_out, sizeof(uint64_t)) <
142        (ssize_t)sizeof(uint64_t))
143        return errno;
144
145    return 0;
146}
147
148int pm_kernel_destroy(pm_kernel_t *ker) {
149    if (!ker)
150        return -1;
151
152    close(ker->kpagecount_fd);
153    close(ker->kpageflags_fd);
154
155    free(ker);
156
157    return 0;
158}
159