src/system.c

   1 /*
   2  * PgBouncer - Lightweight connection pooler for PostgreSQL.
   3  *
   4  * Copyright (c) 2007-2009  Marko Kreen, Skype Technologies OÜ
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 /*
  20  * Compat functions for OSes where libc does not provide them.
  21  */
  22
  23 #include "bouncer.h"
  24
  25 #ifdef HAVE_SYS_PARAM_H
  26 #include <sys/param.h>
  27 #endif
  28 #ifdef HAVE_UCRED_H
  29 #include <ucred.h>
  30 #endif
  31 #ifdef HAVE_SYS_UCRED_H
  32 #include <sys/ucred.h>
  33 #endif
  34 #ifdef HAVE_PWD_H
  35 #include <pwd.h>
  36 #endif
  37 #ifdef HAVE_GRP_H
  38 #include <grp.h>
  39 #endif
  40
  41 /*
  42  * Minimal spec-conforming implementations of strlcpy(), strlcat().
  43  */
  44
  45 #ifndef HAVE_STRLCPY
  46 size_t strlcpy(char *dst, const char *src, size_t n)
  47 {
  48         size_t len = strlen(src);
  49         if (len < n) {
  50                 memcpy(dst, src, len + 1);
  51         } else if (n > 0) {
  52                 memcpy(dst, src, n - 1);
  53                 dst[n - 1] = 0;
  54         }
  55         return len;
  56 }
  57 #endif
  58
  59 #ifndef HAVE_STRLCAT
  60 size_t strlcat(char *dst, const char *src, size_t n)
  61 {
  62         size_t pos = 0;
  63         while (pos < n && dst[pos])
  64                 pos++;
  65         return pos + strlcpy(dst + pos, src, n - pos);
  66 }
  67 #endif
  68
  69 /*
  70  * Get other side's uid for UNIX socket.
  71  *
  72  * Standardise on getpeereid() from BSDs.
  73  */
  74 #ifndef HAVE_GETPEEREID
  75 int getpeereid(int fd, uid_t *uid_p, gid_t *gid_p)
  76 {
  77 #ifdef SO_PEERCRED
  78         struct ucred cred;
  79         socklen_t len = sizeof(cred);
  80         if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cred, &len) >= 0) {
  81                 *uid_p = cred.uid;
  82                 *gid_p = cred.gid;
  83                 return 0;
  84         }
  85 #else /* !SO_PEERCRED */
  86 #ifdef HAVE_GETPEERUCRED
  87         ucred_t *cred = NULL;
  88         if (getpeerucred(fd, &cred) >= 0) {
  89                 *uid_p = ucred_geteuid(cred);
  90                 *gid_p = ucred_getegid(cred);
  91                 ucred_free(cred);
  92                 if (*uid_p >= 0 && *gid_p >= 0)
  93                         return 0;
  94         }
  95 #endif /* HAVE_GETPEERUCRED */
  96 #endif /* !SO_PEERCRED */
  97         return -1;
  98 }
  99 #endif /* !HAVE_GETPEEREID */
 100
 101 #ifndef HAVE_BASENAME
 102 const char *basename(const char *path)
 103 {
 104         const char *p;
 105         if (path == NULL || path[0] == 0)
 106                 return ".";
 107         if ((p = strrchr(path, '/')) != NULL)
 108                 return p[1] ? p + 1 : p;
 109         return path;
 110 }
 111 #endif
 112
 113 void change_user(const char *user)
 114 {
 115         const struct passwd *pw;
 116         gid_t gset[1];
 117
 118         /* check for a valid username */
 119         pw = getpwnam(user);
 120         if (pw == NULL)
 121                 fatal("could not find user '%s' to switch to", user);
 122
 123         gset[0] = pw->pw_gid;
 124         if (getuid() == 0) {
 125                 if (setgroups(1, gset) < 0)
 126                         fatal_perror("failed to reset groups");
 127         }
 128
 129         if (setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0)
 130                 fatal_perror("failed to assume identity of user '%s'", user);
 131
 132         if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
 133                 fatal("setuid() failed to work");
 134 }
 135
 136 #ifndef HAVE_INET_NTOP
 137 const char *inet_ntop(int af, const void *src, char *dst, socklen_t cnt)
 138 {
 139         const unsigned char *p = src;
 140         if (af != AF_INET)
 141                 return NULL;
 142         snprintf(dst, cnt, "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
 143         return dst;
 144 }
 145 #endif
 146
 147