sysinfo.c

linux下获取一些环境信息的代码

    kb_low_free  = kb_main_free;
  }
  if(kb_inactive==~0UL){
    kb_inactive = kb_inact_dirty + kb_inact_clean + kb_inact_laundry;
  }
  kb_swap_used = kb_swap_total - kb_swap_free;
  kb_main_used = kb_main_total - kb_main_free;
}

/*****************************************************************/

/* read /proc/vminfo only for 2.5.41 and above */

typedef struct vm_table_struct {
  const char *name;     /* VM statistic name */
  unsigned long *slot;       /* slot in return struct */
} vm_table_struct;

static int compare_vm_table_structs(const void *a, const void *b){
  return strcmp(((const vm_table_struct*)a)->name,((const vm_table_struct*)b)->name);
}

// see include/linux/page-flags.h and mm/page_alloc.c
unsigned long vm_nr_dirty;           // dirty writable pages
unsigned long vm_nr_writeback;       // pages under writeback
unsigned long vm_nr_pagecache;       // pages in pagecache -- gone in 2.5.66+ kernels
unsigned long vm_nr_page_table_pages;// pages used for pagetables
unsigned long vm_nr_reverse_maps;    // includes PageDirect
unsigned long vm_nr_mapped;          // mapped into pagetables
unsigned long vm_nr_slab;            // in slab
unsigned long vm_pgpgin;             // kB disk reads  (same as 1st num on /proc/stat page line)
unsigned long vm_pgpgout;            // kB disk writes (same as 2nd num on /proc/stat page line)
unsigned long vm_pswpin;             // swap reads     (same as 1st num on /proc/stat swap line)
unsigned long vm_pswpout;            // swap writes    (same as 2nd num on /proc/stat swap line)
unsigned long vm_pgalloc;            // page allocations
unsigned long vm_pgfree;             // page freeings
unsigned long vm_pgactivate;         // pages moved inactive -> active
unsigned long vm_pgdeactivate;       // pages moved active -> inactive
unsigned long vm_pgfault;           // total faults (major+minor)
unsigned long vm_pgmajfault;       // major faults
unsigned long vm_pgscan;          // pages scanned by page reclaim
unsigned long vm_pgrefill;       // inspected by refill_inactive_zone
unsigned long vm_pgsteal;       // total pages reclaimed
unsigned long vm_kswapd_steal; // pages reclaimed by kswapd
// next 3 as defined by the 2.5.52 kernel
unsigned long vm_pageoutrun;  // times kswapd ran page reclaim
unsigned long vm_allocstall; // times a page allocator ran direct reclaim
unsigned long vm_pgrotated; // pages rotated to the tail of the LRU for immediate reclaim
// seen on a 2.6.8-rc1 kernel, apparently replacing old fields
static unsigned long vm_pgalloc_dma;          // 
static unsigned long vm_pgalloc_high;         // 
static unsigned long vm_pgalloc_normal;       // 
static unsigned long vm_pgrefill_dma;         // 
static unsigned long vm_pgrefill_high;        // 
static unsigned long vm_pgrefill_normal;      // 
static unsigned long vm_pgscan_direct_dma;    // 
static unsigned long vm_pgscan_direct_high;   // 
static unsigned long vm_pgscan_direct_normal; // 
static unsigned long vm_pgscan_kswapd_dma;    // 
static unsigned long vm_pgscan_kswapd_high;   // 
static unsigned long vm_pgscan_kswapd_normal; // 
static unsigned long vm_pgsteal_dma;          // 
static unsigned long vm_pgsteal_high;         // 
static unsigned long vm_pgsteal_normal;       // 
// seen on a 2.6.8-rc1 kernel
static unsigned long vm_kswapd_inodesteal;    //
static unsigned long vm_nr_unstable;          //
static unsigned long vm_pginodesteal;         //
static unsigned long vm_slabs_scanned;        //

void vminfo(void){
  char namebuf[16]; /* big enough to hold any row name */
  vm_table_struct findme = { namebuf, NULL};
  vm_table_struct *found;
  char *head;
  char *tail;
  static const vm_table_struct vm_table[] = {
  {"allocstall",          &vm_allocstall},
  {"kswapd_inodesteal",   &vm_kswapd_inodesteal},
  {"kswapd_steal",        &vm_kswapd_steal},
  {"nr_dirty",            &vm_nr_dirty},           // page version of meminfo Dirty
  {"nr_mapped",           &vm_nr_mapped},          // page version of meminfo Mapped
  {"nr_page_table_pages", &vm_nr_page_table_pages},// same as meminfo PageTables
  {"nr_pagecache",        &vm_nr_pagecache},       // gone in 2.5.66+ kernels
  {"nr_reverse_maps",     &vm_nr_reverse_maps},    // page version of meminfo ReverseMaps GONE
  {"nr_slab",             &vm_nr_slab},            // page version of meminfo Slab
  {"nr_unstable",         &vm_nr_unstable},
  {"nr_writeback",        &vm_nr_writeback},       // page version of meminfo Writeback
  {"pageoutrun",          &vm_pageoutrun},
  {"pgactivate",          &vm_pgactivate},
  {"pgalloc",             &vm_pgalloc},  // GONE (now separate dma,high,normal)
  {"pgalloc_dma",         &vm_pgalloc_dma},
  {"pgalloc_high",        &vm_pgalloc_high},
  {"pgalloc_normal",      &vm_pgalloc_normal},
  {"pgdeactivate",        &vm_pgdeactivate},
  {"pgfault",             &vm_pgfault},
  {"pgfree",              &vm_pgfree},
  {"pginodesteal",        &vm_pginodesteal},
  {"pgmajfault",          &vm_pgmajfault},
  {"pgpgin",              &vm_pgpgin},     // important
  {"pgpgout",             &vm_pgpgout},     // important
  {"pgrefill",            &vm_pgrefill},  // GONE (now separate dma,high,normal)
  {"pgrefill_dma",        &vm_pgrefill_dma},
  {"pgrefill_high",       &vm_pgrefill_high},
  {"pgrefill_normal",     &vm_pgrefill_normal},
  {"pgrotated",           &vm_pgrotated},
  {"pgscan",              &vm_pgscan},  // GONE (now separate direct,kswapd and dma,high,normal)
  {"pgscan_direct_dma",   &vm_pgscan_direct_dma},
  {"pgscan_direct_high",  &vm_pgscan_direct_high},
  {"pgscan_direct_normal",&vm_pgscan_direct_normal},
  {"pgscan_kswapd_dma",   &vm_pgscan_kswapd_dma},
  {"pgscan_kswapd_high",  &vm_pgscan_kswapd_high},
  {"pgscan_kswapd_normal",&vm_pgscan_kswapd_normal},
  {"pgsteal",             &vm_pgsteal},  // GONE (now separate dma,high,normal)
  {"pgsteal_dma",         &vm_pgsteal_dma},
  {"pgsteal_high",        &vm_pgsteal_high},
  {"pgsteal_normal",      &vm_pgsteal_normal},
  {"pswpin",              &vm_pswpin},     // important
  {"pswpout",             &vm_pswpout},     // important
  {"slabs_scanned",       &vm_slabs_scanned},
  };
  const int vm_table_count = sizeof(vm_table)/sizeof(vm_table_struct);

  vm_pgalloc = 0;
  vm_pgrefill = 0;
  vm_pgscan = 0;
  vm_pgsteal = 0;

  FILE_TO_BUF(VMINFO_FILE,vminfo_fd);

  head = buf;
  for(;;){
    tail = strchr(head, ' ');
    if(!tail) break;
    *tail = '\0';
    if(strlen(head) >= sizeof(namebuf)){
      head = tail+1;
      goto nextline;
    }
    strcpy(namebuf,head);
    found = bsearch(&findme, vm_table, vm_table_count,
        sizeof(vm_table_struct), compare_vm_table_structs
    );
    head = tail+1;
    if(!found) goto nextline;
    *(found->slot) = strtoul(head,&tail,10);
nextline:

//if(found) fprintf(stderr,"%s=%d\n",found->name,*(found->slot));
//else      fprintf(stderr,"%s not found\n",findme.name);

    tail = strchr(head, '\n');
    if(!tail) break;
    head = tail+1;
  }
  if(!vm_pgalloc)
    vm_pgalloc  = vm_pgalloc_dma + vm_pgalloc_high + vm_pgalloc_normal;
  if(!vm_pgrefill)
    vm_pgrefill = vm_pgrefill_dma + vm_pgrefill_high + vm_pgrefill_normal;
  if(!vm_pgscan)
    vm_pgscan   = vm_pgscan_direct_dma + vm_pgscan_direct_high + vm_pgscan_direct_normal
                + vm_pgscan_kswapd_dma + vm_pgscan_kswapd_high + vm_pgscan_kswapd_normal;
  if(!vm_pgsteal)
    vm_pgsteal  = vm_pgsteal_dma + vm_pgsteal_high + vm_pgsteal_normal;
}

///////////////////////////////////////////////////////////////////////
// based on Fabian Frederick's /proc/diskstats parser


unsigned int getpartitions_num(struct disk_stat *disks, int ndisks){
  int i=0;
  int partitions=0;

  for (i=0;i<ndisks;i++){
	partitions+=disks[i].partitions;
  }
  return partitions;

}

/////////////////////////////////////////////////////////////////////////////

unsigned int getdiskstat(struct disk_stat **disks, struct partition_stat **partitions){
  FILE* fd;
  int cDisk = 0;
  int cPartition = 0;
  int fields;
  unsigned dummy;

  *disks = NULL;
  *partitions = NULL;
  buff[BUFFSIZE-1] = 0; 
  fd = fopen("/proc/diskstats", "rb");
  if(!fd) crash("/proc/diskstats");

  for (;;) {
    if (!fgets(buff,BUFFSIZE-1,fd)){
      fclose(fd);
      break;
    }
    fields = sscanf(buff, " %*d %*d %*s %*u %*u %*u %*u %*u %*u %*u %*u %*u %*u %u", &dummy);
    if (fields == 1){
      (*disks) = realloc(*disks, (cDisk+1)*sizeof(struct disk_stat));
      sscanf(buff,  "   %*d    %*d %15s %u %u %llu %u %u %u %llu %u %u %u %u",
        //&disk_major,
        //&disk_minor,
        (*disks)[cDisk].disk_name,
        &(*disks)[cDisk].reads,
        &(*disks)[cDisk].merged_reads,
        &(*disks)[cDisk].reads_sectors,
        &(*disks)[cDisk].milli_reading,
        &(*disks)[cDisk].writes,
        &(*disks)[cDisk].merged_writes,
        &(*disks)[cDisk].written_sectors,
        &(*disks)[cDisk].milli_writing,
        &(*disks)[cDisk].inprogress_IO,
        &(*disks)[cDisk].milli_spent_IO,
        &(*disks)[cDisk].weighted_milli_spent_IO
      );
        (*disks)[cDisk].partitions=0;
      cDisk++;
    }else{
      (*partitions) = realloc(*partitions, (cPartition+1)*sizeof(struct partition_stat));
      fflush(stdout);
      sscanf(buff,  "   %*d    %*d %15s %u %llu %u %u",
        //&part_major,
        //&part_minor,
        (*partitions)[cPartition].partition_name,
        &(*partitions)[cPartition].reads,
        &(*partitions)[cPartition].reads_sectors,
        &(*partitions)[cPartition].writes,
        &(*partitions)[cPartition].requested_writes
      );
      (*partitions)[cPartition++].parent_disk = cDisk-1;
      (*disks)[cDisk-1].partitions++;	
    }
  }

  return cDisk;
}

/////////////////////////////////////////////////////////////////////////////
// based on Fabian Frederick's /proc/slabinfo parser

unsigned int getslabinfo (struct slab_cache **slab){
  FILE* fd;
  int cSlab = 0;
  buff[BUFFSIZE-1] = 0; 
  *slab = NULL;
  fd = fopen("/proc/slabinfo", "rb");
  if(!fd) crash("/proc/slabinfo");
  while (fgets(buff,BUFFSIZE-1,fd)){
    if(!memcmp("slabinfo - version:",buff,19)) continue; // skip header
    if(*buff == '#')                           continue; // skip comments
    (*slab) = realloc(*slab, (cSlab+1)*sizeof(struct slab_cache));
    sscanf(buff,  "%47s %u %u %u %u",  // allow 47; max seen is 24
      (*slab)[cSlab].name,
      &(*slab)[cSlab].active_objs,
      &(*slab)[cSlab].num_objs,
      &(*slab)[cSlab].objsize,
      &(*slab)[cSlab].objperslab
    ) ;
    cSlab++;
  }
  fclose(fd);
  return cSlab;
}

///////////////////////////////////////////////////////////////////////////

unsigned get_pid_digits(void){
  char pidbuf[24];
  char *endp;
  long rc;
  int fd;
  static unsigned ret;

  if(ret) goto out;
  ret = 5;
  fd = open("/proc/sys/kernel/pid_max", O_RDONLY);
  if(fd==-1) goto out;
  rc = read(fd, pidbuf, sizeof pidbuf);
  close(fd);
  if(rc<3) goto out;
  pidbuf[rc] = '\0';
  rc = strtol(pidbuf,&endp,10);
  if(rc<42) goto out;
  if(*endp && *endp!='\n') goto out;
  rc--;  // the pid_max value is really the max PID plus 1
  ret = 0;
  while(rc){
    rc /= 10;
    ret++;
  }
out:
  return ret;
}