src/common.c

   1 #ifdef HAVE_CONFIG_H
   2 #include <config.h>
   3 #endif
   4 #include <sys/syscall.h>
   5 #include <string.h>
   6 #include <ctype.h>
   7 #include <errno.h>
   8 #include <unistd.h>
   9 #include <sys/types.h>
  10 #include <sys/stat.h>
  11 #include <fcntl.h>
  12 #include <sys/mman.h>
  13
  14
  15 #include "log.h"
  16 #include "common.h"
  17 #include "appconfig.h"
  18
  19 char *global_host_prefix = "";
  20 int enable_ksm = 1;
  21
  22 /*
  23 // http://stackoverflow.com/questions/7666509/hash-function-for-string
  24 uint32_t simple_hash(const char *name)
  25 {
  26         const char *s = name;
  27         uint32_t hash = 5381;
  28         int i;
  29
  30         while((i = *s++)) hash = ((hash << 5) + hash) + i;
  31
  32         // fprintf(stderr, "HASH: %lu %s\n", hash, name);
  33
  34         return hash;
  35 }
  36 */
  37
  38
  39 // http://isthe.com/chongo/tech/comp/fnv/#FNV-1a
  40 uint32_t simple_hash(const char *name) {
  41         unsigned char *s = (unsigned char *)name;
  42         uint32_t hval = 0x811c9dc5;
  43
  44         // FNV-1a algorithm
  45         while (*s) {
  46                 // multiply by the 32 bit FNV magic prime mod 2^32
  47                 // gcc optimized
  48                 hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
  49
  50                 // xor the bottom with the current octet
  51                 hval ^= (uint32_t)*s++;
  52         }
  53
  54         // fprintf(stderr, "HASH: %u = %s\n", hval, name);
  55         return hval;
  56 }
  57
  58 /*
  59 // http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
  60 // one at a time hash
  61 uint32_t simple_hash(const char *name) {
  62         unsigned char *s = (unsigned char *)name;
  63         uint32_t h = 0;
  64
  65         while(*s) {
  66                 h += *s++;
  67                 h += (h << 10);
  68                 h ^= (h >> 6);
  69         }
  70
  71         h += (h << 3);
  72         h ^= (h >> 11);
  73         h += (h << 15);
  74
  75         // fprintf(stderr, "HASH: %u = %s\n", h, name);
  76
  77         return h;
  78 }
  79 */
  80
  81 void strreverse(char* begin, char* end)
  82 {
  83     char aux;
  84     while (end > begin)
  85         aux = *end, *end-- = *begin, *begin++ = aux;
  86 }
  87
  88 char *mystrsep(char **ptr, char *s)
  89 {
  90         char *p = "";
  91         while ( p && !p[0] && *ptr ) p = strsep(ptr, s);
  92         return(p);
  93 }
  94
  95 char *trim(char *s)
  96 {
  97         // skip leading spaces
  98         while(*s && isspace(*s)) s++;
  99         if(!*s || *s == '#') return NULL;
 100
 101         // skip tailing spaces
 102         int c = strlen(s) - 1;
 103         while(c >= 0 && isspace(s[c])) {
 104                 s[c] = '\0';
 105                 c--;
 106         }
 107         if(c < 0) return NULL;
 108         if(!*s) return NULL;
 109         return s;
 110 }
 111
 112 void *mymmap(const char *filename, unsigned long size, int flags, int ksm)
 113 {
 114         int fd;
 115         void *mem = NULL;
 116
 117         errno = 0;
 118         fd = open(filename, O_RDWR|O_CREAT|O_NOATIME, 0664);
 119         if(fd != -1) {
 120                 if(lseek(fd, size, SEEK_SET) == (long)size) {
 121                         if(write(fd, "", 1) == 1) {
 122                                 if(ftruncate(fd, size))
 123                                         error("Cannot truncate file '%s' to size %ld. Will use the larger file.", filename, size);
 124
 125                                 if(flags & MAP_SHARED || !enable_ksm || !ksm) {
 126                                         mem = mmap(NULL, size, PROT_READ|PROT_WRITE, flags, fd, 0);
 127                                         if(mem) {
 128                                                 int advise = MADV_SEQUENTIAL|MADV_DONTFORK;
 129                                                 if(flags & MAP_SHARED) advise |= MADV_WILLNEED;
 130
 131                                                 if(madvise(mem, size, advise) != 0)
 132                                                         error("Cannot advise the kernel about the memory usage of file '%s'.", filename);
 133                                         }
 134                                 }
 135                                 else {
 136                                         mem = mmap(NULL, size, PROT_READ|PROT_WRITE, flags|MAP_ANONYMOUS, -1, 0);
 137                                         if(mem) {
 138                                                 if(lseek(fd, 0, SEEK_SET) == 0) {
 139                                                         if(read(fd, mem, size) != size)
 140                                                                 error("Cannot read from file '%s'", filename);
 141                                                 }
 142                                                 else
 143                                                         error("Cannot seek to beginning of file '%s'.", filename);
 144
 145                                                 // don't use MADV_SEQUENTIAL|MADV_DONTFORK, they disable MADV_MERGEABLE
 146                                                 if(madvise(mem, size, MADV_MERGEABLE) != 0)
 147                                                         error("Cannot advise the kernel about the memory usage of file '%s'.", filename);
 148                                         }
 149                                         else
 150                                                 error("Cannot allocate PRIVATE ANONYMOUS memory for KSM for file '%s'.", filename);
 151                                 }
 152                         }
 153                         else error("Cannot write to file '%s' at position %ld.", filename, size);
 154                 }
 155                 else error("Cannot seek file '%s' to size %ld.", filename, size);
 156
 157                 close(fd);
 158         }
 159         else error("Cannot create/open file '%s'.", filename);
 160
 161         return mem;
 162 }
 163
 164 int savememory(const char *filename, void *mem, unsigned long size)
 165 {
 166         char tmpfilename[FILENAME_MAX + 1];
 167
 168         snprintf(tmpfilename, FILENAME_MAX, "%s.%ld.tmp", filename, (long)getpid());
 169
 170         int fd = open(tmpfilename, O_RDWR|O_CREAT|O_NOATIME, 0664);
 171         if(fd < 0) {
 172                 error("Cannot create/open file '%s'.", filename);
 173                 return -1;
 174         }
 175
 176         if(write(fd, mem, size) != (long)size) {
 177                 error("Cannot write to file '%s' %ld bytes.", filename, (long)size);
 178                 close(fd);
 179                 return -1;
 180         }
 181
 182         close(fd);
 183
 184         int ret = 0;
 185         if(rename(tmpfilename, filename)) {
 186                 error("Cannot rename '%s' to '%s'", tmpfilename, filename);
 187                 ret = -1;
 188         }
 189
 190         return ret;
 191 }
 192
 193 int fd_is_valid(int fd) {
 194     return fcntl(fd, F_GETFD) != -1 || errno != EBADF;
 195 }
 196
 197 /*
 198  ***************************************************************************
 199  * Get number of clock ticks per second.
 200  ***************************************************************************
 201  */
 202 unsigned int hz;
 203
 204 void get_HZ(void)
 205 {
 206         long ticks;
 207
 208         if ((ticks = sysconf(_SC_CLK_TCK)) == -1) {
 209                 perror("sysconf");
 210         }
 211
 212         hz = (unsigned int) ticks;
 213 }
 214
 215 pid_t gettid(void)
 216 {
 217         return syscall(SYS_gettid);
 218 }
 219