wmmemload/src/mem_linux.c

   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 */
  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
  68 INLINE_STATIC char *skip_line(const char *p)
  69 {
  70         while (*p != '\n')
  71                 p++;
  72         return (char *) ++p;
  73 }
  74
  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
  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 */
  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 }