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198

answers:

1
   1:  /*
   2:   * File:   xyn-playlist.c
   3:   * Author: Andrei Ciobanu
   4:   *
   5:   * Created on June 4, 2010, 12:47 PM
   6:   */
   7:   
   8:  #include <dirent.h>
   9:  #include <glib.h>
  10:  #include <stdio.h>
  11:  #include <stdlib.h>
  12:  #include <sys/stat.h>
  13:  #include <unistd.h>
  14:   
  15:  /**
  16:   * Returns a list all the file(paths) from a directory.
  17:   * Returns 'NULL' if a certain error occurs.
  18:   * @param dir_path.
  19:   * @param A list of gchars* indicating what file patterns to detect.
  20:   */
  21:  GSList *xyn_pl_get_files(const gchar *dir_path, GSList *file_patterns) {
  22:      /* Returning list containing file paths */
  23:      GSList *fpaths = NULL;
  24:      /* Used to scan directories for subdirs. Acts like a
  25:       * stack, to avoid recursion. */
  26:      GSList *dirs = NULL;
  27:      /* Current dir */
  28:      DIR *cdir = NULL;
  29:      /* Current dir entries */
  30:      struct dirent *cent = NULL;
  31:      /* File stats */
  32:      struct stat cent_stat;
  33:      /* dir_path duplicate, on the heap */
  34:      gchar *dir_pdup;
  35:   
  36:      if (dir_path == NULL) {
  37:          return NULL;
  38:      }
  39:   
  40:      dir_pdup = g_strdup((const gchar*) dir_path);
  41:      dirs = g_slist_append(dirs, (gpointer) dir_pdup);
  42:      while (dirs != NULL) {
  43:          cdir = opendir((const gchar*) dirs->data);
  44:          if (cdir == NULL) {
  45:              g_slist_free(dirs);
  46:              g_slist_free(fpaths);
  47:              return NULL;
  48:          }
  49:          chdir((const gchar*) dirs->data);
  50:          while ((cent = readdir(cdir)) != NULL) {
  51:              lstat(cent->d_name, &cent_stat);
  52:              if (S_ISDIR(cent_stat.st_mode)) {
  53:                  if (g_strcmp0(cent->d_name, ".") == 0 ||
  54:                          g_strcmp0(cent->d_name, "..") == 0) {
  55:                      /* Skip "." and ".." dirs */
  56:                      continue;
  57:                  }
  58:                  dirs = g_slist_append(dirs,
  59:                          g_strconcat((gchar*) dirs->data, "/", cent->d_name, NULL));
  60:              } else {
  61:                  fpaths = g_slist_append(fpaths,
  62:                          g_strconcat((gchar*) dirs->data, "/", cent->d_name, NULL));
  63:              }
  64:          }
  65:          g_free(dirs->data);
  66:          dirs = g_slist_delete_link(dirs, dirs);
  67:          closedir(cdir);
  68:      }
  69:      return fpaths;
  70:  }
  71:   
  72:  int main(int argc, char** argv) {
  73:      GSList *l = NULL;
  74:      l = xyn_pl_get_files("/home/andrei/Music", NULL);
  75:      g_slist_foreach(l,(GFunc)printf,NULL);
  76:      printf("%d\n",g_slist_length(l));
  77:      g_slist_free(l);
  78:      return (0);
  79:  }
  80:   
  81:   
  82:  -----------------------------------------------------------------------------------------------==15429== 
  83:  ==15429== HEAP SUMMARY:
  84:  ==15429==     in use at exit: 751,451 bytes in 7,263 blocks
  85:  ==15429==   total heap usage: 8,611 allocs, 1,348 frees, 22,898,217 bytes allocated
  86:  ==15429== 
  87:  ==15429== 120 bytes in 1 blocks are possibly lost in loss record 1 of 11
  88:  ==15429==    at 0x4024106: memalign (vg_replace_malloc.c:581)
  89:  ==15429==    by 0x4024163: posix_memalign (vg_replace_malloc.c:709)
  90:  ==15429==    by 0x40969C1: ??? (in /lib/libglib-2.0.so.0.2400.1)
  91:  ==15429==    by 0x40971F6: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
  92:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
  93:  ==15429==    by 0x80488F0: xyn_pl_get_files (xyn-playlist.c:41)
  94:  ==15429==    by 0x8048848: main (main.c:18)
  95:  ==15429== 
  96:  ==15429== 129 bytes in 1 blocks are possibly lost in loss record 2 of 11
  97:  ==15429==    at 0x4024F20: malloc (vg_replace_malloc.c:236)
  98:  ==15429==    by 0x4081243: g_malloc (in /lib/libglib-2.0.so.0.2400.1)
  99:  ==15429==    by 0x409B85B: g_strconcat (in /lib/libglib-2.0.so.0.2400.1)
 100:  ==15429==    by 0x80489FE: xyn_pl_get_files (xyn-playlist.c:62)
 101:  ==15429==    by 0x8048848: main (main.c:18)
 102:  ==15429== 
 103:  ==15429== 360 bytes in 3 blocks are possibly lost in loss record 3 of 11
 104:  ==15429==    at 0x4024106: memalign (vg_replace_malloc.c:581)
 105:  ==15429==    by 0x4024163: posix_memalign (vg_replace_malloc.c:709)
 106:  ==15429==    by 0x40969C1: ??? (in /lib/libglib-2.0.so.0.2400.1)
 107:  ==15429==    by 0x4097222: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
 108:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
 109:  ==15429==    by 0x80488F0: xyn_pl_get_files (xyn-playlist.c:41)
 110:  ==15429==    by 0x8048848: main (main.c:18)
 111:  ==15429== 
 112:  ==15429== 508 bytes in 1 blocks are still reachable in loss record 4 of 11
 113:  ==15429==    at 0x402425F: calloc (vg_replace_malloc.c:467)
 114:  ==15429==    by 0x408113B: g_malloc0 (in /lib/libglib-2.0.so.0.2400.1)
 115:  ==15429==    by 0x409624D: ??? (in /lib/libglib-2.0.so.0.2400.1)
 116:  ==15429==    by 0x409710C: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
 117:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
 118:  ==15429==    by 0x80488F0: xyn_pl_get_files (xyn-playlist.c:41)
 119:  ==15429==    by 0x8048848: main (main.c:18)
 120:  ==15429== 
 121:  ==15429== 508 bytes in 1 blocks are still reachable in loss record 5 of 11
 122:  ==15429==    at 0x402425F: calloc (vg_replace_malloc.c:467)
 123:  ==15429==    by 0x408113B: g_malloc0 (in /lib/libglib-2.0.so.0.2400.1)
 124:  ==15429==    by 0x409626F: ??? (in /lib/libglib-2.0.so.0.2400.1)
 125:  ==15429==    by 0x409710C: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
 126:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
 127:  ==15429==    by 0x80488F0: xyn_pl_get_files (xyn-playlist.c:41)
 128:  ==15429==    by 0x8048848: main (main.c:18)
 129:  ==15429== 
 130:  ==15429== 508 bytes in 1 blocks are still reachable in loss record 6 of 11
 131:  ==15429==    at 0x402425F: calloc (vg_replace_malloc.c:467)
 132:  ==15429==    by 0x408113B: g_malloc0 (in /lib/libglib-2.0.so.0.2400.1)
 133:  ==15429==    by 0x4096291: ??? (in /lib/libglib-2.0.so.0.2400.1)
 134:  ==15429==    by 0x409710C: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
 135:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
 136:  ==15429==    by 0x80488F0: xyn_pl_get_files (xyn-playlist.c:41)
 137:  ==15429==    by 0x8048848: main (main.c:18)
 138:  ==15429== 
 139:  ==15429== 1,200 bytes in 10 blocks are possibly lost in loss record 7 of 11
 140:  ==15429==    at 0x4024106: memalign (vg_replace_malloc.c:581)
 141:  ==15429==    by 0x4024163: posix_memalign (vg_replace_malloc.c:709)
 142:  ==15429==    by 0x40969C1: ??? (in /lib/libglib-2.0.so.0.2400.1)
 143:  ==15429==    by 0x40971F6: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
 144:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
 145:  ==15429==    by 0x8048A0D: xyn_pl_get_files (xyn-playlist.c:61)
 146:  ==15429==    by 0x8048848: main (main.c:18)
 147:  ==15429== 
 148:  ==15429== 2,040 bytes in 1 blocks are still reachable in loss record 8 of 11
 149:  ==15429==    at 0x402425F: calloc (vg_replace_malloc.c:467)
 150:  ==15429==    by 0x408113B: g_malloc0 (in /lib/libglib-2.0.so.0.2400.1)
 151:  ==15429==    by 0x40970AB: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
 152:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
 153:  ==15429==    by 0x80488F0: xyn_pl_get_files (xyn-playlist.c:41)
 154:  ==15429==    by 0x8048848: main (main.c:18)
 155:  ==15429== 
 156:  ==15429== 4,320 bytes in 36 blocks are possibly lost in loss record 9 of 11
 157:  ==15429==    at 0x4024106: memalign (vg_replace_malloc.c:581)
 158:  ==15429==    by 0x4024163: posix_memalign (vg_replace_malloc.c:709)
 159:  ==15429==    by 0x40969C1: ??? (in /lib/libglib-2.0.so.0.2400.1)
 160:  ==15429==    by 0x4097222: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
 161:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
 162:  ==15429==    by 0x80489D2: xyn_pl_get_files (xyn-playlist.c:58)
 163:  ==15429==    by 0x8048848: main (main.c:18)
 164:  ==15429== 
 165:  ==15429== 56,640 bytes in 472 blocks are possibly lost in loss record 10 of 11
 166:  ==15429==    at 0x4024106: memalign (vg_replace_malloc.c:581)
 167:  ==15429==    by 0x4024163: posix_memalign (vg_replace_malloc.c:709)
 168:  ==15429==    by 0x40969C1: ??? (in /lib/libglib-2.0.so.0.2400.1)
 169:  ==15429==    by 0x4097222: g_slice_alloc (in /lib/libglib-2.0.so.0.2400.1)
 170:  ==15429==    by 0x40988A5: g_slist_append (in /lib/libglib-2.0.so.0.2400.1)
 171:  ==15429==    by 0x8048A0D: xyn_pl_get_files (xyn-playlist.c:61)
 172:  ==15429==    by 0x8048848: main (main.c:18)
 173:  ==15429== 
 174:  ==15429== 685,118 bytes in 6,736 blocks are definitely lost in loss record 11 of 11
 175:  ==15429==    at 0x4024F20: malloc (vg_replace_malloc.c:236)
 176:  ==15429==    by 0x4081243: g_malloc (in /lib/libglib-2.0.so.0.2400.1)
 177:  ==15429==    by 0x409B85B: g_strconcat (in /lib/libglib-2.0.so.0.2400.1)
 178:  ==15429==    by 0x80489FE: xyn_pl_get_files (xyn-playlist.c:62)
 179:  ==15429==    by 0x8048848: main (main.c:18)
 180:  ==15429== 
 181:  ==15429== LEAK SUMMARY:
 182:  ==15429==    definitely lost: 685,118 bytes in 6,736 blocks
 183:  ==15429==    indirectly lost: 0 bytes in 0 blocks
 184:  ==15429==      possibly lost: 62,769 bytes in 523 blocks
 185:  ==15429==    still reachable: 3,564 bytes in 4 blocks
 186:  ==15429==         suppressed: 0 bytes in 0 blocks
 187:  ==15429== 
 188:  ==15429== For counts of detected and suppressed errors, rerun with: -v
 189:  ==15429== ERROR SUMMARY: 7 errors from 7 contexts (suppressed: 17 from 8)
 190:  ----------------------------------------------------------------------------------------------

I am using the above code in order to create a list with all the filepaths in a certain directory. (In my case fts.h or ftw.h are not an option).

I am using GLib as the data structures library. Still I have my doubts in regarding the way GLib is allocating, de-allocating memory ?

When invoking g_slist_free(list) i also free the data contained by the elements ? Why all those memory leaks appear ? Is valgrind a suitable tool for profilinf memory issues when using a complex library like GLib ?

LATER EDIT:

If I g_slist_foreach(l,(GFunc)g_free,NULL);, the valgrind report is different, (All the memory leaks from 'definitely lost' will move to 'indirectly lost'). Still I don't see the point ? Aren't GLib collections implement a way to be freed ?

+2  A: 

No, g_slist_free does not free data you store in the list (e.g. strings). It has no way of knowing whether and how you want to free this data. You might store the same pointer in multiple lists. Also, you can store non-pointer types in the list, or types that aren't allocated with malloc. The collection doesn't let you provide a destructor function. So you do need to loop through and free your data before freeing the list.

Also, g_slist can use memory pools, so valgrind may not always give correct results.

Other types, such as GPtrArray, let you provide a destructor (GDestroyNotify) for element data.

Matthew Flaschen
I think `GSList` uses the slice allocator by default. If you set the environment variable `G_SLICE` to `always-malloc` then it will go back to using malloc/free so Valgrind can trace it.
ptomato