src/lib/lttng-ctl/filter/memstream.h

   1 #ifndef _LTTNG_CTL_MEMSTREAM_H
   2 #define _LTTNG_CTL_MEMSTREAM_H
   3
   4 /*
   5  * src/lib/lttng-ctl/memstream.h
   6  *
   7  * Copyright 2012 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * memstream compatibility layer.
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a copy
  12  * of this software and associated documentation files (the "Software"), to deal
  13  * in the Software without restriction, including without limitation the rights
  14  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15  * copies of the Software, and to permit persons to whom the Software is
  16  * furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be included in
  19  * all copies or substantial portions of the Software.
  20  */
  21
  22 #ifdef LTTNG_HAVE_FMEMOPEN
  23 #include <stdio.h>
  24
  25 static inline
  26 FILE *lttng_fmemopen(void *buf, size_t size, const char *mode)
  27 {
  28         return fmemopen(buf, size, mode);
  29 }
  30
  31 #else /* LTTNG_HAVE_FMEMOPEN */
  32
  33 #include <stdlib.h>
  34 #include <stdio.h>
  35 #include <common/error.h>
  36
  37 /*
  38  * Fallback for systems which don't have fmemopen. Copy buffer to a
  39  * temporary file, and use that file as FILE * input.
  40  */
  41 static inline
  42 FILE *lttng_fmemopen(void *buf, size_t size, const char *mode)
  43 {
  44         char tmpname[PATH_MAX];
  45         size_t len;
  46         FILE *fp;
  47         int ret;
  48
  49         /*
  50          * Support reading only.
  51          */
  52         if (strcmp(mode, "rb") != 0) {
  53                 return NULL;
  54         }
  55         strncpy(tmpname, "/tmp/lttng-tmp-XXXXXX", PATH_MAX);
  56         ret = mkstemp(tmpname);
  57         if (ret < 0) {
  58                 return NULL;
  59         }
  60         /*
  61          * We need to write to the file.
  62          */
  63         fp = fdopen(ret, "w+");
  64         if (!fp) {
  65                 goto error_unlink;
  66         }
  67         /* Copy the entire buffer to the file */
  68         len = fwrite(buf, sizeof(char), size, fp);
  69         if (len != size) {
  70                 goto error_close;
  71         }
  72         ret = fseek(fp, 0L, SEEK_SET);
  73         if (ret < 0) {
  74                 PERROR("fseek");
  75                 goto error_close;
  76         }
  77         /* We keep the handle open, but can unlink the file on the VFS. */
  78         ret = unlink(tmpname);
  79         if (ret < 0) {
  80                 PERROR("unlink");
  81         }
  82         return fp;
  83
  84 error_close:
  85         ret = fclose(fp);
  86         if (ret < 0) {
  87                 PERROR("close");
  88         }
  89 error_unlink:
  90         ret = unlink(tmpname);
  91         if (ret < 0) {
  92                 PERROR("unlink");
  93         }
  94         return NULL;
  95 }
  96
  97 #endif /* LTTNG_HAVE_FMEMOPEN */
  98
  99 #endif /* _LTTNG_CTL_MEMSTREAM_H */