root/shared/session.c

/* */

---

DEFINITIONS

This source file includes following definitions.

1. session_name
2. session_create
3. session_destroy
4. session_open
5. session_close

---

   1 /*
   2 ** Copyright (c) 2024 Amelia Campbell
   3 **
   4 ** Redistribution and use in source and binary forms, with or without
   5 ** modification, are permitted provided that the following conditions are
   6 ** met:
   7 **
   8 **  1. Redistributions of source code must retain the above copyright
   9 **     notice, this list of conditions and the following disclaimer.
  10 **  2. Redistributions in binary form must reproduce the above copyright
  11 **     notice, this list of conditions and the following disclaimer in the
  12 **     documentation and/or other materials provided with the
  13 **     distribution.
  14 **  3. Neither the name of the copyright holder nor the names of its
  15 **     contributors may be used to endorse or promote products derived
  16 **     from this software without specific prior written permission.
  17 **
  18 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  19 ** IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  20 ** TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  21 ** PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22 ** HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29 */
  30 
  31 #include <fcntl.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <errno.h>
  36 #include <unistd.h>
  37 #include <sys/types.h>
  38 #include <sys/mman.h>
  39 #include <sys/stat.h>
  40 #include <openssl/evp.h>
  41 
  42 #include "macro.h"
  43 #include "term.h"
  44 #include "hash.h"
  45 
  46 #define MAXNAME 128
  47 #define SESZ HASH_TSZ
  48 
  49 unsigned char *session = NULL;
  50 char sname[MAXNAME];
  51 
  52 static void session_name(void)
  53     {
  54     char *user;
  55     if (!(user = getenv("USER")))
  56         fatal("agent failed to acquire name from USER env\n");
  57 
  58     snprintf(sname, MAXNAME, "/dsesU%s", user);
  59     }
  60 
  61 
  62 void session_create(unsigned char *k, size_t kl)
  63     {
  64     hash_t skey;
  65     int fd;
  66     session_name();
  67     if ((fd = shm_open(sname, O_CREAT|O_EXCL|O_RDWR, S_IRUSR|S_IWUSR))<0)
  68         fatal("agent shm failed to create: %s\n", strerror(errno));
  69     if (ftruncate(fd, SESZ) < 0)
  70         fatal("agent shm could not be truncated to correct size\n");
  71     if (MAP_FAILED == (session = mmap(NULL, SESZ,
  72                                       PROT_READ|PROT_WRITE,
  73                                       MAP_FILE|MAP_SHARED, fd, 0)))
  74         fatal("agent shm could not be mapped into memory\n");
  75 
  76     genkey(k, kl, &skey);
  77     memcpy(session, skey.r, SESZ);
  78     munmap(session, SESZ);
  79     close(fd);
  80     }
  81 
  82 
  83 void session_destroy(void)
  84     {
  85     session_name();
  86     if (shm_unlink(sname) < 0)
  87         fatal("failed to unlink agent shm (does it even exist?)\n");
  88     }
  89 
  90 
  91 int session_open(void)
  92     {
  93     int fd;
  94     session_name();
  95     if ((fd = shm_open(sname, O_RDONLY, 0)) < 0)
  96         return -1;
  97     if (MAP_FAILED == (session = mmap(NULL, SESZ,
  98                                       PROT_READ,
  99                                       MAP_FILE, fd, 0)))
 100         fatal("agent shm could not be mapped into memory\n");
 101     close(fd);
 102     return 0;
 103     }
 104 
 105 
 106 void session_close(void)
 107     {
 108     if (!session) return;
 109     munmap(session, SESZ);
 110     }

---

/* */