core: Add thread-safe group info functions with dynamic buffers

Provides getgrgid, getgrnam, getpwuid & getpwnam replacements that are
thread safe (a la getgrgid_r() and friends) that internally
handle allocating big-enough buffers to avoid ERANGE errors
on large users or groups.

6 files changed, 643 insertions, 115 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index fd440991..73c0db5b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -280,7 +280,8 @@ TESTS = \
 		proplist-test \
 		lock-autospawn-test \
 		prioq-test \
-		sigbus-test
+		sigbus-test \
+		usergroup-test
 
 TESTS_BINARIES = \
 		mainloop-test \
@@ -318,7 +319,8 @@ TESTS_BINARIES = \
 		stripnul \
 		lock-autospawn-test \
 		prioq-test \
-		sigbus-test
+		sigbus-test \
+		usergroup-test
 
 if HAVE_SIGXCPU
 #TESTS += \
@@ -557,6 +559,11 @@ alsa_time_test_LDADD = $(AM_LDADD)
 alsa_time_test_CFLAGS = $(AM_CFLAGS) $(ASOUNDLIB_CFLAGS)
 alsa_time_test_LDFLAGS = $(AM_LDFLAGS) $(BINLDFLAGS) $(ASOUNDLIB_LIBS)
 
+usergroup_test_SOURCES = tests/usergroup-test.c
+usergroup_test_LDADD = $(AM_LDADD) libpulsecore-@PA_MAJORMINORMICRO@.la
+usergroup_test_CFLAGS = $(AM_CFLAGS)
+usergroup_test_LDFLAGS = $(AM_LDFLAGS) $(BINLDFLAGS)
+
 ###################################
 #         Common library          #
 ###################################
@@ -621,6 +628,7 @@ libpulsecommon_@PA_MAJORMINORMICRO@_la_SOURCES = \
 		pulsecore/tagstruct.c pulsecore/tagstruct.h \
 		pulsecore/time-smoother.c pulsecore/time-smoother.h \
 		pulsecore/tokenizer.c pulsecore/tokenizer.h \
+		pulsecore/usergroup.c pulsecore/usergroup.h \
 		pulsecore/sndfile-util.c pulsecore/sndfile-util.h \
 		pulsecore/winsock.h
 
diff --git a/src/pulse/util.c b/src/pulse/util.c
index 6f1e40a9..9440f5de 100644
--- a/src/pulse/util.c
+++ b/src/pulse/util.c
@@ -61,38 +61,40 @@
 #include <pulsecore/log.h>
 #include <pulsecore/core-util.h>
 #include <pulsecore/macro.h>
+#include <pulsecore/usergroup.h>
 
 #include "util.h"
 
 char *pa_get_user_name(char *s, size_t l) {
     const char *p;
+    char *name = NULL;
+#ifdef OS_IS_WIN32
     char buf[1024];
+#endif
 
 #ifdef HAVE_PWD_H
-    struct passwd pw, *r;
+    struct passwd *r;
 #endif
 
     pa_assert(s);
     pa_assert(l > 0);
 
-    if (!(p = (getuid() == 0 ? "root" : NULL)) &&
-        !(p = getenv("USER")) &&
-        !(p = getenv("LOGNAME")) &&
-        !(p = getenv("USERNAME"))) {
+    if ((p = (getuid() == 0 ? "root" : NULL)) ||
+        (p = getenv("USER")) ||
+        (p = getenv("LOGNAME")) ||
+        (p = getenv("USERNAME")))
+    {
+        name = pa_strlcpy(s, p, l);
+    } else {
 #ifdef HAVE_PWD_H
 
-#ifdef HAVE_GETPWUID_R
-        if (getpwuid_r(getuid(), &pw, buf, sizeof(buf), &r) != 0 || !r) {
-#else
-        /* XXX Not thread-safe, but needed on OSes (e.g. FreeBSD 4.X)
-            * that do not support getpwuid_r. */
-        if ((r = getpwuid(getuid())) == NULL) {
-#endif
+        if ((r = pa_getpwuid_malloc(getuid())) == NULL) {
             pa_snprintf(s, l, "%lu", (unsigned long) getuid());
             return s;
         }
 
-        p = r->pw_name;
+        name = pa_strlcpy(s, r->pw_name, l);
+        pa_getpwuid_free(r);
 
 #elif defined(OS_IS_WIN32) /* HAVE_PWD_H */
         DWORD size = sizeof(buf);
@@ -102,7 +104,7 @@ char *pa_get_user_name(char *s, size_t l) {
             return NULL;
         }
 
-        p = buf;
+        name = pa_strlcpy(s, buf, l);
 
 #else /* HAVE_PWD_H */
 
@@ -110,7 +112,7 @@ char *pa_get_user_name(char *s, size_t l) {
 #endif /* HAVE_PWD_H */
     }
 
-    return pa_strlcpy(s, p, l);
+    return name;
 }
 
 char *pa_get_host_name(char *s, size_t l) {
@@ -126,11 +128,10 @@ char *pa_get_host_name(char *s, size_t l) {
 }
 
 char *pa_get_home_dir(char *s, size_t l) {
-    char *e;
+    char *e, *dir;
 
 #ifdef HAVE_PWD_H
-    char buf[1024];
-    struct passwd pw, *r;
+    struct passwd *r;
 #endif
 
     pa_assert(s);
@@ -143,22 +144,19 @@ char *pa_get_home_dir(char *s, size_t l) {
         return pa_strlcpy(s, e, l);
 
 #ifdef HAVE_PWD_H
-
     errno = 0;
-#ifdef HAVE_GETPWUID_R
-    if (getpwuid_r(getuid(), &pw, buf, sizeof(buf), &r) != 0 || !r) {
-#else
-    /* XXX Not thread-safe, but needed on OSes (e.g. FreeBSD 4.X)
-        * that do not support getpwuid_r. */
-    if ((r = getpwuid(getuid())) == NULL) {
-#endif
+    if ((r = pa_getpwuid_malloc(getuid())) == NULL) {
         if (!errno)
             errno = ENOENT;
 
         return NULL;
     }
 
-    return pa_strlcpy(s, r->pw_dir, l);
+    dir = pa_strlcpy(s, r->pw_dir, l);
+
+    pa_getpwuid_free(r);
+
+    return dir;
 #else /* HAVE_PWD_H */
 
     errno = ENOENT;
diff --git a/src/pulsecore/core-util.c b/src/pulsecore/core-util.c
index 843c8377..0eb32cc4 100644
--- a/src/pulsecore/core-util.c
+++ b/src/pulsecore/core-util.c
@@ -115,6 +115,7 @@
 #include <pulsecore/macro.h>
 #include <pulsecore/thread.h>
 #include <pulsecore/strbuf.h>
+#include <pulsecore/usergroup.h>
 
 #include "core-util.h"
 
@@ -969,42 +970,24 @@ fail:
 
 /* Check whether the specified GID and the group name match */
 static int is_group(gid_t gid, const char *name) {
-    struct group group, *result = NULL;
-    long n;
-    void *data;
+    struct group *group = NULL;
     int r = -1;
 
-#ifdef HAVE_GETGRGID_R
-
-#ifdef _SC_GETGR_R_SIZE_MAX
-    n = sysconf(_SC_GETGR_R_SIZE_MAX);
-#else
-    n = -1;
-#endif
-    if (n <= 0)
-        n = 512;
-
-    data = pa_xmalloc((size_t) n);
-
-    if ((errno = getgrgid_r(gid, &group, data, (size_t) n, &result)) || !result)
-#else
     errno = 0;
-    if (!(result = getgrgid(gid)))
-#endif
+    if (!(group = pa_getgrgid_malloc(gid)))
     {
         if (!errno)
             errno = ENOENT;
 
-        pa_log("getgrgid(%u): %s", gid, pa_cstrerror(errno));
+        pa_log("pa_getgrgid_malloc(%u): %s", gid, pa_cstrerror(errno));
 
         goto finish;
     }
 
-    r = strcmp(name, result->gr_name) == 0;
+    r = strcmp(name, group->gr_name) == 0;
 
 finish:
-
-    pa_xfree(data);
+    pa_getgrgid_free(group);
 
     return r;
 }
@@ -1053,69 +1036,37 @@ finish:
 
 /* Check whether the specifc user id is a member of the specified group */
 int pa_uid_in_group(uid_t uid, const char *name) {
-    char *g_buf = NULL, *p_buf = NULL;
-    long g_n, p_n;
-    struct group grbuf, *gr = NULL;
+    struct group *group = NULL;
     char **i;
     int r = -1;
 
-#ifdef HAVE_GETGRNAM_R
-
-#ifdef _SC_GETGR_R_SIZE_MAX
-    g_n = sysconf(_SC_GETGR_R_SIZE_MAX);
-#else
-    g_n = -1;
-#endif
-    if (g_n <= 0)
-        g_n = 512;
-
-    g_buf = pa_xmalloc((size_t) g_n);
-
-    if ((errno = getgrnam_r(name, &grbuf, g_buf, (size_t) g_n, &gr)) != 0 || !gr)
-#else
     errno = 0;
-    if (!(gr = getgrnam(name)))
-#endif
+    if (!(group = pa_getgrnam_malloc(name)))
     {
         if (!errno)
             errno = ENOENT;
         goto finish;
     }
 
-#ifdef HAVE_GETPWNAM_R
-
-#ifdef _SC_GETPW_R_SIZE_MAX
-    p_n = sysconf(_SC_GETPW_R_SIZE_MAX);
-#else
-    p_n = -1;
-#endif
-    if (p_n <= 0)
-        p_n = 512;
-
-    p_buf = pa_xmalloc((size_t) p_n);
-#endif
-
     r = 0;
-    for (i = gr->gr_mem; *i; i++) {
-        struct passwd pwbuf, *pw = NULL;
+    for (i = group->gr_mem; *i; i++) {
+        struct passwd *pw = NULL;
 
-#ifdef HAVE_GETPWNAM_R
-        if ((errno = getpwnam_r(*i, &pwbuf, p_buf, (size_t) p_n, &pw)) != 0 || !pw)
-#else
         errno = 0;
-        if (!(pw = getpwnam(*i)))
-#endif
+        if (!(pw = pa_getpwnam_malloc(*i)))
             continue;
 
-        if (pw->pw_uid == uid) {
+        if (pw->pw_uid == uid)
             r = 1;
+
+        pa_getpwnam_free(pw);
+
+        if (r == 1)
             break;
-        }
     }
 
 finish:
-    pa_xfree(g_buf);
-    pa_xfree(p_buf);
+    pa_getgrnam_free(group);
 
     return r;
 }
@@ -1123,27 +1074,10 @@ finish:
 /* Get the GID of a gfiven group, return (gid_t) -1 on failure. */
 gid_t pa_get_gid_of_group(const char *name) {
     gid_t ret = (gid_t) -1;
-    char *g_buf = NULL;
-    long g_n;
-    struct group grbuf, *gr = NULL;
-
-#ifdef HAVE_GETGRNAM_R
-
-#ifdef _SC_GETGR_R_SIZE_MAX
-    g_n = sysconf(_SC_GETGR_R_SIZE_MAX);
-#else
-    g_n = -1;
-#endif
-    if (g_n <= 0)
-        g_n = 512;
-
-    g_buf = pa_xmalloc((size_t) g_n);
+    struct group *gr = NULL;
 
-    if ((errno = getgrnam_r(name, &grbuf, g_buf, (size_t) g_n, &gr)) != 0 || !gr)
-#else
     errno = 0;
-    if (!(gr = getgrnam(name)))
-#endif
+    if (!(gr = pa_getgrnam_malloc(name)))
     {
         if (!errno)
             errno = ENOENT;
@@ -1153,7 +1087,7 @@ gid_t pa_get_gid_of_group(const char *name) {
     ret = gr->gr_gid;
 
 finish:
-    pa_xfree(g_buf);
+    pa_getgrnam_free(gr);
     return ret;
 }
 
diff --git a/src/pulsecore/usergroup.c b/src/pulsecore/usergroup.c
new file mode 100644
index 00000000..bf686b77
--- /dev/null
+++ b/src/pulsecore/usergroup.c
@@ -0,0 +1,376 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2009 Ted Percival
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <sys/types.h>
+#include <errno.h>
+
+#ifdef HAVE_PWD_H
+#include <pwd.h>
+#endif
+
+#ifdef HAVE_GRP_H
+#include <grp.h>
+#endif
+
+#include <pulse/xmalloc.h>
+#include <pulsecore/macro.h>
+
+#include "usergroup.h"
+
+#ifdef HAVE_GRP_H
+
+/* Returns a suitable starting size for a getgrnam_r() or getgrgid_r() buffer,
+   plus the size of a struct group.
+ */
+static size_t starting_getgr_buflen(void) {
+    size_t full_size;
+    long n;
+#ifdef _SC_GETGR_R_SIZE_MAX
+    n = sysconf(_SC_GETGR_R_SIZE_MAX);
+#else
+    n = -1;
+#endif
+    if (n <= 0)
+        n = 512;
+
+    full_size = (size_t) n + sizeof(struct group);
+
+    if (full_size < (size_t) n) /* check for integer overflow */
+        return (size_t) n;
+
+    return full_size;
+}
+
+/* Returns a suitable starting size for a getpwnam_r() or getpwuid_r() buffer,
+   plus the size of a struct passwd.
+ */
+static size_t starting_getpw_buflen(void) {
+    long n;
+    size_t full_size;
+
+#ifdef _SC_GETPW_R_SIZE_MAX
+    n = sysconf(_SC_GETPW_R_SIZE_MAX);
+#else
+    n = -1;
+#endif
+    if (n <= 0)
+        n = 512;
+
+    full_size = (size_t) n + sizeof(struct passwd);
+
+    if (full_size < (size_t) n) /* check for integer overflow */
+        return (size_t) n;
+
+    return full_size;
+}
+
+/* Given a memory allocation (*bufptr) and its length (*buflenptr),
+   double the size of the allocation, updating the given buffer and length
+   arguments. This function should be used in conjunction with the pa_*alloc
+   and pa_xfree functions.
+
+   Unlike realloc(), this function does *not* retain the original buffer's
+   contents.
+
+   Returns 0 on success, nonzero on error. The error cause is indicated by
+   errno.
+ */
+static int expand_buffer_trashcontents(void **bufptr, size_t *buflenptr) {
+    size_t newlen;
+
+    if (!bufptr || !*bufptr || !buflenptr) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    newlen = *buflenptr * 2;
+
+    if (newlen < *buflenptr) {
+        errno = EOVERFLOW;
+        return -1;
+    }
+
+    /* Don't bother retaining memory contents; free & alloc anew */
+    pa_xfree(*bufptr);
+
+    *bufptr = pa_xmalloc(newlen);
+    *buflenptr = newlen;
+
+    return 0;
+}
+
+#ifdef HAVE_GETGRGID_R
+/* Thread-safe getgrgid() replacement.
+   Returned value should be freed using pa_getgrgid_free() when the caller is
+   finished with the returned group data.
+
+   API is the same as getgrgid(), errors are indicated by a NULL return;
+   consult errno for the error cause (zero it before calling).
+   The returned value must be freed using pa_xfree().
+ */
+struct group *pa_getgrgid_malloc(gid_t gid) {
+    size_t buflen, getgr_buflen;
+    int err;
+    void *buf;
+    void *getgr_buf;
+    struct group *result = NULL;
+
+    buflen = starting_getgr_buflen();
+    buf = pa_xmalloc(buflen);
+
+    getgr_buflen = buflen - sizeof(struct group);
+    getgr_buf = (char *)buf + sizeof(struct group);
+
+    while ((err = getgrgid_r(gid, (struct group *)buf, getgr_buf,
+                    getgr_buflen, &result)) == ERANGE)
+    {
+        if (expand_buffer_trashcontents(&buf, &buflen))
+            break;
+
+        getgr_buflen = buflen - sizeof(struct group);
+        getgr_buf = (char *)buf + sizeof(struct group);
+    }
+
+    if (err || !result) {
+        result = NULL;
+        if (buf) {
+            pa_xfree(buf);
+            buf = NULL;
+        }
+    }
+
+    pa_assert(result == buf || result == NULL);
+
+    return result;
+}
+
+void pa_getgrgid_free(struct group *grp) {
+    pa_xfree(grp);
+}
+
+#else /* !HAVE_GETGRGID_R */
+
+struct group *pa_getgrgid_malloc(gid_t gid) {
+    return getgrgid(gid);
+}
+
+void pa_getgrgid_free(struct group *grp) {
+    /* nothing */
+    return;
+}
+
+#endif /* !HAVE_GETGRGID_R */
+
+#ifdef HAVE_GETGRNAM_R
+/* Thread-safe getgrnam() function.
+   Returned value should be freed using pa_getgrnam_free() when the caller is
+   finished with the returned group data.
+
+   API is the same as getgrnam(), errors are indicated by a NULL return;
+   consult errno for the error cause (zero it before calling).
+   The returned value must be freed using pa_xfree().
+ */
+struct group *pa_getgrnam_malloc(const char *name) {
+    size_t buflen, getgr_buflen;
+    int err;
+    void *buf;
+    void *getgr_buf;
+    struct group *result = NULL;
+
+    buflen = starting_getgr_buflen();
+    buf = pa_xmalloc(buflen);
+
+    getgr_buflen = buflen - sizeof(struct group);
+    getgr_buf = (char *)buf + sizeof(struct group);
+
+    while ((err = getgrnam_r(name, (struct group *)buf, getgr_buf,
+                    getgr_buflen, &result)) == ERANGE)
+    {
+        if (expand_buffer_trashcontents(&buf, &buflen))
+            break;
+
+        getgr_buflen = buflen - sizeof(struct group);
+        getgr_buf = (char *)buf + sizeof(struct group);
+    }
+
+    if (err || !result) {
+        result = NULL;
+        if (buf) {
+            pa_xfree(buf);
+            buf = NULL;
+        }
+    }
+
+    pa_assert(result == buf || result == NULL);
+
+    return result;
+}
+
+void pa_getgrnam_free(struct group *group) {
+    pa_xfree(group);
+}
+
+#else /* !HAVE_GETGRNAM_R */
+
+struct group *pa_getgrnam_malloc(const char *name) {
+    return getgrnam(name);
+}
+
+void pa_getgrnam_free(struct group *group) {
+    /* nothing */
+    return;
+}
+
+#endif /* HAVE_GETGRNAM_R */
+
+#endif /* HAVE_GRP_H */
+
+#ifdef HAVE_PWD_H
+
+#ifdef HAVE_GETPWNAM_R
+/* Thread-safe getpwnam() function.
+   Returned value should be freed using pa_getpwnam_free() when the caller is
+   finished with the returned passwd data.
+
+   API is the same as getpwnam(), errors are indicated by a NULL return;
+   consult errno for the error cause (zero it before calling).
+   The returned value must be freed using pa_xfree().
+ */
+struct passwd *pa_getpwnam_malloc(const char *name) {
+    size_t buflen, getpw_buflen;
+    int err;
+    void *buf;
+    void *getpw_buf;
+    struct passwd *result = NULL;
+
+    buflen = starting_getpw_buflen();
+    buf = pa_xmalloc(buflen);
+
+    getpw_buflen = buflen - sizeof(struct passwd);
+    getpw_buf = (char *)buf + sizeof(struct passwd);
+
+    while ((err = getpwnam_r(name, (struct passwd *)buf, getpw_buf,
+                    getpw_buflen, &result)) == ERANGE)
+    {
+        if (expand_buffer_trashcontents(&buf, &buflen))
+            break;
+
+        getpw_buflen = buflen - sizeof(struct passwd);
+        getpw_buf = (char *)buf + sizeof(struct passwd);
+    }
+
+    if (err || !result) {
+        result = NULL;
+        if (buf) {
+            pa_xfree(buf);
+            buf = NULL;
+        }
+    }
+
+    pa_assert(result == buf || result == NULL);
+
+    return result;
+}
+
+void pa_getpwnam_free(struct passwd *passwd) {
+    pa_xfree(passwd);
+}
+
+#else /* !HAVE_GETPWNAM_R */
+
+struct passwd *pa_getpwnam_malloc(const char *name) {
+    return getpwnam(name);
+}
+
+void pa_getpwnam_free(struct passwd *passwd) {
+    /* nothing */
+    return;
+}
+
+#endif /* !HAVE_GETPWNAM_R */
+
+#ifdef HAVE_GETPWUID_R
+/* Thread-safe getpwuid() function.
+   Returned value should be freed using pa_getpwuid_free() when the caller is
+   finished with the returned group data.
+
+   API is the same as getpwuid(), errors are indicated by a NULL return;
+   consult errno for the error cause (zero it before calling).
+   The returned value must be freed using pa_xfree().
+ */
+struct passwd *pa_getpwuid_malloc(uid_t uid) {
+    size_t buflen, getpw_buflen;
+    int err;
+    void *buf;
+    void *getpw_buf;
+    struct passwd *result = NULL;
+
+    buflen = starting_getpw_buflen();
+    buf = pa_xmalloc(buflen);
+
+    getpw_buflen = buflen - sizeof(struct passwd);
+    getpw_buf = (char *)buf + sizeof(struct passwd);
+
+    while ((err = getpwuid_r(uid, (struct passwd *)buf, getpw_buf,
+                    getpw_buflen, &result)) == ERANGE)
+    {
+        if (expand_buffer_trashcontents(&buf, &buflen))
+            break;
+
+        getpw_buflen = buflen - sizeof(struct passwd);
+        getpw_buf = (char *)buf + sizeof(struct passwd);
+    }
+
+    if (err || !result) {
+        result = NULL;
+        if (buf) {
+            pa_xfree(buf);
+            buf = NULL;
+        }
+    }
+
+    pa_assert(result == buf || result == NULL);
+
+    return result;
+}
+
+void pa_getpwuid_free(struct passwd *passwd) {
+    pa_xfree(passwd);
+}
+
+#else /* !HAVE_GETPWUID_R */
+
+struct passwd *pa_getpwuid_malloc(uid_t uid) {
+    return getpwuid(uid);
+}
+
+void pa_getpwuid_free(struct passwd *passwd) {
+    /* nothing */
+    return;
+}
+
+#endif /* !HAVE_GETPWUID_R */
+
+#endif /* HAVE_PWD_H */
diff --git a/src/pulsecore/usergroup.h b/src/pulsecore/usergroup.h
new file mode 100644
index 00000000..1c091638
--- /dev/null
+++ b/src/pulsecore/usergroup.h
@@ -0,0 +1,51 @@
+#ifndef foousergrouphfoo
+#define foousergrouphfoo
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2009 Ted Percival
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#include <sys/types.h>
+
+#ifndef PACKAGE
+#error "Please include config.h before including this file!"
+#endif
+
+#ifdef HAVE_GRP_H
+
+struct group *pa_getgrgid_malloc(gid_t gid);
+void pa_getgrgid_free(struct group *grp);
+
+struct group *pa_getgrnam_malloc(const char *name);
+void pa_getgrnam_free(struct group *group);
+
+#endif /* HAVE_GRP_H */
+
+#ifdef HAVE_PWD_H
+
+struct passwd *pa_getpwuid_malloc(uid_t uid);
+void pa_getpwuid_free(struct passwd *passwd);
+
+struct passwd *pa_getpwnam_malloc(const char *name);
+void pa_getpwnam_free(struct passwd *passwd);
+
+#endif /* HAVE_PWD_H */
+
+#endif /* foousergrouphfoo */
diff --git a/src/tests/usergroup-test.c b/src/tests/usergroup-test.c
new file mode 100644
index 00000000..a48b016d
--- /dev/null
+++ b/src/tests/usergroup-test.c
@@ -0,0 +1,161 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2009 Ted Percival
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <grp.h>
+#include <errno.h>
+
+#include <pulsecore/usergroup.h>
+
+static int load_reference_structs(struct group **gr, struct passwd **pw) {
+    setpwent();
+    *pw = getpwent();
+    endpwent();
+
+    setgrent();
+    *gr = getgrent();
+    endgrent();
+
+    return (*gr && *pw) ? 0 : 1;
+}
+
+static int compare_group(const struct group *a, const struct group *b) {
+    char **amem, **bmem;
+
+    if (strcmp(a->gr_name, b->gr_name)) {
+        fprintf(stderr, "Group name mismatch: [%s] [%s]\n",
+                a->gr_name, b->gr_name);
+        return 1;
+    }
+
+    if (strcmp(a->gr_passwd, b->gr_passwd)) {
+        fprintf(stderr, "Group password mismatch: [%s] [%s]\n",
+                a->gr_passwd, b->gr_passwd);
+        return 1;
+    }
+
+    if (a->gr_gid != b->gr_gid) {
+        fprintf(stderr, "Gid mismatch: [%lu] [%lu]\n",
+                (unsigned long) a->gr_gid, (unsigned long) b->gr_gid);
+        return 1;
+    }
+
+    /* XXX: Assuming the group ordering is identical. */
+    for (amem = a->gr_mem, bmem = b->gr_mem; *amem && *bmem; ++amem, ++bmem) {
+        if (strcmp(*amem, *bmem)) {
+            fprintf(stderr, "Group member mismatch: [%s] [%s]\n",
+                    *amem, *bmem);
+            return 1;
+        }
+    }
+
+    if (*amem || *bmem) {
+        fprintf(stderr, "Mismatched group count\n");
+        return 1;
+    }
+
+    return 0;
+}
+
+static int compare_passwd(const struct passwd *a, const struct passwd *b) {
+    if (strcmp(a->pw_name, b->pw_name)) {
+        fprintf(stderr, "pw_name mismatch: [%s] [%s]\n", a->pw_name, b->pw_name);
+        return 1;
+    }
+
+    if (strcmp(a->pw_passwd, b->pw_passwd)) {
+        fprintf(stderr, "pw_passwd mismatch: [%s] [%s]\n", a->pw_passwd, b->pw_passwd);
+        return 1;
+    }
+
+    if (a->pw_uid != b->pw_uid) {
+        fprintf(stderr, "pw_uid mismatch: [%lu] [%lu]\n",
+		(unsigned long) a->pw_uid, (unsigned long) b->pw_uid);
+        return 1;
+    }
+
+    if (a->pw_gid != b->pw_gid) {
+        fprintf(stderr, "pw_gid mismatch: [%lu] [%lu]\n",
+		(unsigned long) a->pw_gid, (unsigned long) b->pw_gid);
+        return 1;
+    }
+
+    if (strcmp(a->pw_gecos, b->pw_gecos)) {
+        fprintf(stderr, "pw_gecos mismatch: [%s] [%s]\n", a->pw_gecos, b->pw_gecos);
+        return 1;
+    }
+
+    if (strcmp(a->pw_dir, b->pw_dir)) {
+        fprintf(stderr, "pw_dir mismatch: [%s] [%s]\n", a->pw_dir, b->pw_dir);
+        return 1;
+    }
+
+    if (strcmp(a->pw_shell, b->pw_shell)) {
+        fprintf(stderr, "pw_shell mismatch: [%s] [%s]\n", a->pw_shell, b->pw_shell);
+        return 1;
+    }
+
+    return 0;
+}
+
+int main(int argc, char *argv[]) {
+    struct group *gr;
+    struct passwd *pw;
+    int err;
+    struct group *reference_group = NULL;
+    struct passwd *reference_passwd = NULL;
+
+    err = load_reference_structs(&reference_group, &reference_passwd);
+    if (err)
+        return 77;
+
+    errno = 0;
+    gr = pa_getgrgid_malloc(reference_group->gr_gid);
+    if (compare_group(reference_group, gr))
+        return 1;
+    pa_getgrgid_free(gr);
+
+    errno = 0;
+    gr = pa_getgrnam_malloc(reference_group->gr_name);
+    if (compare_group(reference_group, gr))
+        return 1;
+    pa_getgrnam_free(gr);
+
+    errno = 0;
+    pw = pa_getpwuid_malloc(reference_passwd->pw_uid);
+    if (compare_passwd(reference_passwd, pw))
+        return 1;
+    pa_getpwuid_free(pw);
+
+    errno = 0;
+    pw = pa_getpwnam_malloc(reference_passwd->pw_name);
+    if (compare_passwd(reference_passwd, pw))
+        return 1;
+    pa_getpwnam_free(pw);
+
+    return 0;
+}