src/common/compat/socket.h

   1 /*
   2  * Copyright (C) 2011 David Goulet <dgoulet@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifndef _COMPAT_SOCKET_H
   9 #define _COMPAT_SOCKET_H
  10
  11 #include <sys/socket.h>
  12 #include <sys/un.h>
  13
  14 #include <common/macros.h>
  15
  16 #ifndef MSG_NOSIGNAL
  17 # ifdef SO_NOSIGPIPE
  18 #   define MSG_NOSIGNAL SO_NOSIGPIPE
  19 # endif
  20 #endif
  21
  22 #if defined(MSG_NOSIGNAL)
  23 static inline
  24 ssize_t lttng_recvmsg_nosigpipe(int sockfd, struct msghdr *msg)
  25 {
  26         return recvmsg(sockfd, msg, MSG_NOSIGNAL);
  27 }
  28 #else
  29
  30 #include <signal.h>
  31 #include <errno.h>
  32
  33 static inline
  34 ssize_t lttng_recvmsg_nosigpipe(int sockfd, struct msghdr *msg)
  35 {
  36         ssize_t received;
  37         int saved_err;
  38         sigset_t sigpipe_set, pending_set, old_set;
  39         int sigpipe_was_pending;
  40
  41         /*
  42          * Discard the SIGPIPE from send(), not disturbing any SIGPIPE
  43          * that might be already pending. If a bogus SIGPIPE is sent to
  44          * the entire process concurrently by a malicious user, it may
  45          * be simply discarded.
  46          */
  47         if (sigemptyset(&pending_set)) {
  48                 return -1;
  49         }
  50         /*
  51          * sigpending returns the mask of signals that are _both_
  52          * blocked for the thread _and_ pending for either the thread or
  53          * the entire process.
  54          */
  55         if (sigpending(&pending_set)) {
  56                 return -1;
  57         }
  58         sigpipe_was_pending = sigismember(&pending_set, SIGPIPE);
  59         /*
  60          * If sigpipe was pending, it means it was already blocked, so
  61          * no need to block it.
  62          */
  63         if (!sigpipe_was_pending) {
  64                 if (sigemptyset(&sigpipe_set)) {
  65                         return -1;
  66                 }
  67                 if (sigaddset(&sigpipe_set, SIGPIPE)) {
  68                         return -1;
  69                 }
  70                 if (pthread_sigmask(SIG_BLOCK, &sigpipe_set, &old_set)) {
  71                         return -1;
  72                 }
  73         }
  74
  75         /* Send and save errno. */
  76         received = recvmsg(sockfd, msg, 0);
  77         saved_err = errno;
  78
  79         if (received == -1 && errno == EPIPE && !sigpipe_was_pending) {
  80                 struct timespec timeout = { 0, 0 };
  81                 int ret;
  82
  83                 do {
  84                         ret = sigtimedwait(&sigpipe_set, NULL,
  85                                 &timeout);
  86                 } while (ret == -1 && errno == EINTR);
  87         }
  88         if (!sigpipe_was_pending) {
  89                 if (pthread_sigmask(SIG_SETMASK, &old_set, NULL)) {
  90                         return -1;
  91                 }
  92         }
  93         /* Restore send() errno */
  94         errno = saved_err;
  95
  96         return received;
  97 }
  98 #endif
  99
 100
 101 #ifdef __linux__
 102
 103 #define LTTNG_SOCK_CREDS SCM_CREDENTIALS
 104
 105 typedef struct ucred lttng_sock_cred;
 106
 107 #define LTTNG_SOCK_SET_UID_CRED(c, u) LTTNG_REF(c)->uid = u
 108 #define LTTNG_SOCK_SET_GID_CRED(c, g) LTTNG_REF(c)->gid = g
 109 #define LTTNG_SOCK_SET_PID_CRED(c, p) LTTNG_REF(c)->pid = p
 110
 111 #define LTTNG_SOCK_GET_UID_CRED(c) LTTNG_REF(c)->uid
 112 #define LTTNG_SOCK_GET_GID_CRED(c) LTTNG_REF(c)->gid
 113 #define LTTNG_SOCK_GET_PID_CRED(c) LTTNG_REF(c)->pid
 114
 115 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 116
 117 struct lttng_sock_cred {
 118         uid_t uid;
 119         gid_t gid;
 120 };
 121
 122 typedef struct lttng_sock_cred lttng_sock_cred;
 123
 124 #define LTTNG_SOCK_GET_UID_CRED(c) LTTNG_REF(c)->uid
 125 #define LTTNG_SOCK_GET_GID_CRED(c) LTTNG_REF(c)->gid
 126 #define LTTNG_SOCK_GET_PID_CRED(c) -1
 127
 128 #else
 129 #error "Please add support for your OS."
 130 #endif /* __linux__ , __FreeBSD__ */
 131
 132
 133 #ifdef __sun__
 134
 135 # ifndef CMSG_ALIGN
 136 #  ifdef _CMSG_DATA_ALIGN
 137 #   define CMSG_ALIGN(len) _CMSG_DATA_ALIGN(len)
 138 #  else
 139     /* aligning to sizeof (long) is assumed to be portable (fd.o#40235) */
 140 #   define CMSG_ALIGN(len) (((len) + sizeof (long) - 1) & ~(sizeof (long) - 1))
 141 #  endif
 142 #  ifndef CMSG_SPACE
 143 #    define CMSG_SPACE(len) (CMSG_ALIGN (sizeof (struct cmsghdr)) + CMSG_ALIGN (len))
 144 #  endif
 145 #  ifndef CMSG_LEN
 146 #    define CMSG_LEN(len) (CMSG_ALIGN (sizeof (struct cmsghdr)) + (len))
 147 #  endif
 148 # endif
 149
 150
 151 #include <ucred.h>
 152
 153 static inline
 154 int getpeereid(int s, uid_t *euid, gid_t *gid)
 155 {
 156         int ret = 0;
 157         ucred_t *ucred = NULL;
 158
 159         ret = getpeerucred(s, &ucred);
 160         if (ret == -1) {
 161                 goto end;
 162         }
 163
 164         ret = ucred_geteuid(ucred);
 165         if (ret == -1) {
 166                 goto free;
 167         }
 168         *euid = ret;
 169
 170         ret = ucred_getrgid(ucred);
 171         if (ret == -1) {
 172                 goto free;
 173         }
 174         *gid = ret;
 175         ret = 0;
 176 free:
 177         ucred_free(ucred);
 178 end:
 179         return ret;
 180 }
 181
 182 #endif /* __sun__ */
 183
 184 #endif /* _COMPAT_SOCKET_H */