1 /*
2 * mem_linux.c - module to get memory/swap usages, for GNU/Linxu
3 *
4 * Copyright(C) 2001,2002 Seiichi SATO <ssato@sh.rim.or.jp>
5 * Copyright(C) 2001 John McCutchan <ttb@tentacle.dhs.org>
6 *
7 * licensed under the GPL
8 */
9
10 #ifdef HAVE_CONFIG_H
11 #include "config.h"
12 #endif
13
14 #include <stdio.h>
15 #include <unistd.h>
16 #include <stdlib.h>
17
18 #if defined(HAVE_STRING_H)
19 #include <string.h>
20 #elif defined(HAVE_STRINGS_H)
21 #include <strings.h>
22 #endif
23
24 #include <sys/types.h>
25 #include <sys/stat.h>
26 #include <fcntl.h>
27 #include <ctype.h>
28 #include <sys/utsname.h>
29 #include "mem.h"
30
31 static enum {
32 BEFORE_2_5_1,
33 BETWEEN_2_5_1_AND_3_14,
34 AFTER_3_14
35 } format;
36
37 #ifdef DEBUG
38 # define INLINE_STATIC static
39 #else
40 # define INLINE_STATIC static inline
41 #endif
42
43 /* initialize function */
mem_init(void)44 void mem_init(void)
45 {
46 struct utsname un;
47 int version, patchlevel, sublevel;
48
49 /* get kernel version */
50 if (uname(&un) == -1)
51 perror("uname()");
52 sscanf(un.release, "%d.%d.%d", &version, &patchlevel, &sublevel);
53
54 /* new format ? (kernel >= 3.14 or 2.5.1pre?) */
55 /* see linux/fs/proc/proc_misc.c */
56 /* or linux/fs/proc/meminfo.c */
57 if ((version == 3 && patchlevel >= 14) || version > 3)
58 format = AFTER_3_14;
59 else if ((version == 2 && patchlevel >= 5 && sublevel >= 1) ||
60 (version == 2 && patchlevel >= 6 && sublevel >= 0) ||
61 version > 2)
62 format = BETWEEN_2_5_1_AND_3_14;
63 else
64 format = BEFORE_2_5_1;
65 }
66
67
skip_line(const char * p)68 INLINE_STATIC char *skip_line(const char *p)
69 {
70 while (*p != '\n')
71 p++;
72 return (char *) ++p;
73 }
74
skip_token(const char * p)75 INLINE_STATIC char *skip_token(const char *p)
76 {
77 while (isspace(*p))
78 p++;
79 while (*p && !isspace(*p))
80 p++;
81 return (char *)p;
82 }
83
skip_multiple_token(const char * p,int count)84 INLINE_STATIC char *skip_multiple_token(const char *p, int count)
85 {
86 int i;
87 for (i = 0; i < count; i++)
88 p = skip_token(p);
89 return (char *)p;
90 }
91
92 /* return mem/swap usage in percent 0 to 100 */
mem_getusage(int * per_mem,int * per_swap,const struct mem_options * opts)93 void mem_getusage(int *per_mem, int *per_swap, const struct mem_options *opts)
94 {
95 char buffer[BUFSIZ], *p;
96 int fd, len, i;
97 u_int64_t mtotal, mused, mfree, mbuffer, mcached;
98 u_int64_t stotal, sused, sfree, scached = 0;
99
100 /* read /proc/meminfo */
101 fd = open("/proc/meminfo", O_RDONLY);
102 if (fd < 0) {
103 perror("can't open /proc/meminfo");
104 exit(1);
105 }
106 len = read(fd, buffer, BUFSIZ - 1);
107 if (len < 0) {
108 perror("can't read /proc/meminfo");
109 exit(1);
110 }
111 close(fd);
112
113 buffer[len] = '\0';
114 p = buffer;
115
116 switch (format) {
117 case (BEFORE_2_5_1):
118 /* skip 3 lines */
119 for (i = 0; i < 3; i++)
120 p = skip_line(p);
121 p = skip_token(p);
122 /* examine each line of file */
123 mtotal = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
124 mfree = strtoul(p, &p, 0); p = skip_multiple_token(p, 5);
125 mbuffer = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
126 mcached = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
127 scached = strtoul(p, &p, 0);
128 break;
129
130 case (BETWEEN_2_5_1_AND_3_14):
131 p = skip_token(p);
132 /* examine each line of file */
133 mtotal = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
134 mfree = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
135 mbuffer = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
136 mcached = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
137 scached = strtoul(p, &p, 0);
138 break;
139
140 case (AFTER_3_14):
141 p = skip_token(p);
142 /* examine each line of file */
143 mtotal = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
144 mfree = strtoul(p, &p, 0);
145 p = skip_multiple_token(p, 5); /* skip MemAvailable line */
146 mbuffer = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
147 mcached = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
148 scached = strtoul(p, &p, 0);
149 break;
150 }
151
152
153 /* skip N lines and examine info about swap */
154 /* kernel-2.4.2:N=8 2.4.16:N=7 */
155 while (isprint(p[0])) {
156 p = skip_line(p);
157 if (strncmp(p, "SwapTotal", 9) == 0)
158 break;
159 }
160
161 p = skip_token(p);
162 stotal = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
163 sfree = strtoul(p, &p, 0);
164
165 /* calculate memory usage in percent */
166 mused = mtotal - mfree;
167 if (opts->ignore_buffers)
168 mused -= mbuffer;
169 if (opts->ignore_cached)
170 mused -= mcached;
171 *per_mem = 100 * (double) mused / (double) mtotal;
172
173 /* calculate swap usage in percent */
174 sused = stotal - sfree;
175 if (opts->ignore_cached)
176 sused -= scached;
177 if (!stotal)
178 *per_swap = 0;
179 else
180 *per_swap = 100 * (double) sused / (double) stotal;
181
182 #if DEBUG
183 printf("-----------------------\n");
184 printf("MemTotal: %12ld\n", (unsigned long)mtotal);
185 printf("MemFree: %12ld\n", (unsigned long)mfree);
186 printf("Buffers: %12ld\n", (unsigned long)mbuffer);
187 printf("Cached: %12ld\n", (unsigned long)mcached);
188 printf("SwapTotal: %12ld\n", (unsigned long)stotal);
189 printf("SwapFree: %12ld\n", (unsigned long)sfree);
190 printf("SwapCached:%12ld\n", (unsigned long)scached);
191 printf("-----------------------\n\n");
192 #endif
193
194 }
195