Date: Fri, 14 Jun 2002 14:54:53 +0100
From: Isaac Wilcox <iwilcox at eatstatic dot net>
To: Andrew Ford <A.Ford@ford-mason.co.uk>
Subject: cronolog set{u,g}id patch

Hi,

I've hacked cronolog to include options to set UID/GID before doing
anything else. The patch is included. I make no claims whatsoever about
its quality, fitness for purpose, etc, but It Works For Me (TM).
It's yours to do with as you will, and I hope it helps.

Just hope nobody already did this (it was listed in some cronolog TODO I
saw somewhere).

Isaac Wilcox


diff -Naur configure configure
--- configure	Thu May  3 17:44:22 2001
+++ configure	Mon Jun  3 00:38:32 2002
@@ -1757,15 +1757,49 @@
 
 fi
 
+echo $ac_n "checking for uid_t in sys/types.h""... $ac_c" 1>&6
+echo "configure:1762: checking for uid_t in sys/types.h" >&5
+if eval "test \"`echo '$''{'ac_cv_type_uid_t'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  cat > conftest.$ac_ext <<EOF
+#line 1767 "configure"
+#include "confdefs.h"
+#include <sys/types.h>
+EOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  egrep "uid_t" >/dev/null 2>&1; then
+  rm -rf conftest*
+  ac_cv_type_uid_t=yes
+else
+  rm -rf conftest*
+  ac_cv_type_uid_t=no
+fi
+rm -f conftest*
+
+fi
+
+echo "$ac_t""$ac_cv_type_uid_t" 1>&6
+if test $ac_cv_type_uid_t = no; then
+  cat >> confdefs.h <<\EOF
+#define uid_t int
+EOF
+
+  cat >> confdefs.h <<\EOF
+#define gid_t int
+EOF
+
+fi
+
 
 
 echo $ac_n "checking for strftime""... $ac_c" 1>&6
-echo "configure:1764: checking for strftime" >&5
+echo "configure:1798: checking for strftime" >&5
 if eval "test \"`echo '$''{'ac_cv_func_strftime'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1769 "configure"
+#line 1803 "configure"
 #include "confdefs.h"
 /* System header to define __stub macros and hopefully few prototypes,
     which can conflict with char strftime(); below.  */
@@ -1788,7 +1822,7 @@
 
 ; return 0; }
 EOF
-if { (eval echo configure:1792: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:1826: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_func_strftime=yes"
 else
@@ -1810,7 +1844,7 @@
   echo "$ac_t""no" 1>&6
 # strftime is in -lintl on SCO UNIX.
 echo $ac_n "checking for strftime in -lintl""... $ac_c" 1>&6
-echo "configure:1814: checking for strftime in -lintl" >&5
+echo "configure:1848: checking for strftime in -lintl" >&5
 ac_lib_var=`echo intl'_'strftime | sed 'y%./+-%__p_%'`
 if eval "test \"`echo '$''{'ac_cv_lib_$ac_lib_var'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
@@ -1818,7 +1852,7 @@
   ac_save_LIBS="$LIBS"
 LIBS="-lintl  $LIBS"
 cat > conftest.$ac_ext <<EOF
-#line 1822 "configure"
+#line 1856 "configure"
 #include "confdefs.h"
 /* Override any gcc2 internal prototype to avoid an error.  */
 /* We use char because int might match the return type of a gcc2
@@ -1829,7 +1863,7 @@
 strftime()
 ; return 0; }
 EOF
-if { (eval echo configure:1833: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:1867: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_lib_$ac_lib_var=yes"
 else
@@ -1856,12 +1890,12 @@
 fi
 
 echo $ac_n "checking for vprintf""... $ac_c" 1>&6
-echo "configure:1860: checking for vprintf" >&5
+echo "configure:1894: checking for vprintf" >&5
 if eval "test \"`echo '$''{'ac_cv_func_vprintf'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1865 "configure"
+#line 1899 "configure"
 #include "confdefs.h"
 /* System header to define __stub macros and hopefully few prototypes,
     which can conflict with char vprintf(); below.  */
@@ -1884,7 +1918,7 @@
 
 ; return 0; }
 EOF
-if { (eval echo configure:1888: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:1922: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_func_vprintf=yes"
 else
@@ -1908,12 +1942,12 @@
 
 if test "$ac_cv_func_vprintf" != yes; then
 echo $ac_n "checking for _doprnt""... $ac_c" 1>&6
-echo "configure:1912: checking for _doprnt" >&5
+echo "configure:1946: checking for _doprnt" >&5
 if eval "test \"`echo '$''{'ac_cv_func__doprnt'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1917 "configure"
+#line 1951 "configure"
 #include "confdefs.h"
 /* System header to define __stub macros and hopefully few prototypes,
     which can conflict with char _doprnt(); below.  */
@@ -1936,7 +1970,7 @@
 
 ; return 0; }
 EOF
-if { (eval echo configure:1940: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:1974: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_func__doprnt=yes"
 else
@@ -1963,12 +1997,12 @@
 for ac_func in mkdir mktime putenv
 do
 echo $ac_n "checking for $ac_func""... $ac_c" 1>&6
-echo "configure:1967: checking for $ac_func" >&5
+echo "configure:2001: checking for $ac_func" >&5
 if eval "test \"`echo '$''{'ac_cv_func_$ac_func'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1972 "configure"
+#line 2006 "configure"
 #include "confdefs.h"
 /* System header to define __stub macros and hopefully few prototypes,
     which can conflict with char $ac_func(); below.  */
@@ -1991,7 +2025,7 @@
 
 ; return 0; }
 EOF
-if { (eval echo configure:1995: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:2029: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_func_$ac_func=yes"
 else
@@ -2018,12 +2052,12 @@
 for ac_func in strptime localtime_r
 do
 echo $ac_n "checking for $ac_func""... $ac_c" 1>&6
-echo "configure:2022: checking for $ac_func" >&5
+echo "configure:2056: checking for $ac_func" >&5
 if eval "test \"`echo '$''{'ac_cv_func_$ac_func'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 2027 "configure"
+#line 2061 "configure"
 #include "confdefs.h"
 /* System header to define __stub macros and hopefully few prototypes,
     which can conflict with char $ac_func(); below.  */
@@ -2046,7 +2080,7 @@
 
 ; return 0; }
 EOF
-if { (eval echo configure:2050: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:2084: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_func_$ac_func=yes"
 else
diff -Naur configure.in configure.in
--- configure.in	Thu May  3 17:30:50 2001
+++ configure.in	Mon Jun  3 00:38:32 2002
@@ -56,6 +56,7 @@
 AC_C_CONST
 AC_TYPE_SIZE_T
 AC_STRUCT_TM
+AC_TYPE_UID_T
 
 dnl Checks for library functions.
 
diff -Naur doc/cronolog.1m doc/cronolog.1m
--- doc/cronolog.1m	Fri May  4 09:44:55 2001
+++ doc/cronolog.1m	Mon Jun  3 00:39:10 2002
@@ -89,6 +89,20 @@
 .IP --help
 print a help message and then exit.
 .\"
+.IP "-u \fIUSER\fP"
+.IP "--set-uid=\fIUSER\fP"
+sets the user ID of the cronolog process before any logs are opened.
+\fIUSER\fP can be a username or a numeric user ID. If \fIUSER\fP
+contains solely digits, it will be assumed to be a numeric user ID;
+otherwise, it will be assumed to be a username.
+.\"
+.IP "-g \fIGROUP\fP"
+.IP "--set-gid=\fIGROUP\fP"
+sets the group ID of the cronolog process before any logs are opened.
+\fIGROUP\fP can be a group name or a numeric group ID. If \fIGROUP\fP
+contains solely digits, it will be assumed to be a numeric group ID;
+otherwise, it will be assumed to be a group name.
+.\"
 .IP "-p \fIPERIOD\fP"
 .IP "--period=\fIPERIOD\fP"
 specifies the period explicitly as an optional digit string followed
diff -Naur src/cronolog.c src/cronolog.c
--- src/cronolog.c	Thu May  3 17:42:48 2001
+++ src/cronolog.c	Mon Jun  3 00:38:32 2002
@@ -100,6 +100,12 @@
 #define VERSION_MSG      "cronolog version 0.1\n"
 #endif
 
+#ifndef _WIN32
+#define SETUGID_USAGE	"   -u USER,   --set-uid=USER  change to USER before doing anything (name or UID)\n" \
+			"   -g GROUP,  --set-gid=GROUP change to GROUP before doing anything (name or GID)\n"
+#else
+#define SETUGID_USAGE	""
+#endif
 
 #define USAGE_MSG 	"usage: %s [OPTIONS] logfile-spec\n" \
 			"\n" \
@@ -117,12 +123,17 @@
 			"   -e,        --european         European date formats (default)\n" \
 			"   -s,    --start-time=TIME   starting time\n" \
 			"   -z TZ, --time-zone=TZ      use TZ for timezone\n" \
+			SETUGID_USAGE \
 			"   -V,      --version         print version number, then exit\n"
 
 
 /* Definition of the short and long program options */
 
+#ifndef _WIN32
+char          *short_options = "ad:eop:s:z:H:P:S:l:hVx:u:g:";
+#else
 char          *short_options = "ad:eop:s:z:H:P:S:l:hVx:";
+#endif        
 
 #ifndef _WIN32
 struct option long_options[] =
@@ -137,6 +148,8 @@
     { "link",      	required_argument, 	NULL, 'l' },
     { "period",		required_argument,	NULL, 'p' },
     { "delay",		required_argument,	NULL, 'd' },
+    { "set-uid",      	required_argument,     	NULL, 'u' },
+    { "set-gid",      	required_argument,     	NULL, 'g' },
     { "once-only", 	no_argument,       	NULL, 'o' },
     { "help",      	no_argument,       	NULL, 'h' },
     { "version",   	no_argument,       	NULL, 'V' }
@@ -160,6 +173,12 @@
     char	*template;
     char	*linkname = NULL;
     char	*prevlinkname = NULL;
+#ifndef _WIN32
+    uid_t	new_uid = 0;
+    gid_t	new_gid = 0;
+    int		change_uid = 0;
+    int		change_gid = 0;
+#endif
     mode_t	linktype = 0;
     int 	n_bytes_read;
     int		ch;
@@ -234,6 +253,16 @@
 	    }		
 	    break;
 	    
+#ifndef _WIN32
+	case 'u':
+	    new_uid = parse_uid(optarg, argv[0]);
+	    change_uid = 1;
+	    break;
+	case 'g':
+	    new_gid = parse_gid(optarg, argv[0]);
+	    change_gid = 1;
+	    break;
+#endif
 	case 'o':
 	    periodicity = ONCE_ONLY;
 	    break;
@@ -265,6 +294,17 @@
 	fprintf(stderr, USAGE_MSG, argv[0]);
 	exit(1);
     }
+
+#ifndef _WIN32
+    if (change_gid && setgid(new_gid) == -1) {
+	fprintf(stderr, "setgid: unable to change to gid: %d\n", new_gid);
+       	exit(1);
+    }
+    if (change_uid && setuid(new_uid) == -1) {
+	fprintf(stderr, "setuid: unable to change to uid: %d\n", new_uid);
+       	exit(1);
+    }
+#endif
 
     DEBUG((VERSION_MSG "\n"));
 
diff -Naur src/cronoutils.c src/cronoutils.c
--- src/cronoutils.c	Thu May  3 17:43:21 2001
+++ src/cronoutils.c	Mon Jun  3 00:38:32 2002
@@ -710,4 +710,50 @@
     return retval;
 }
 
-    
+
+#ifndef _WIN32
+/* Turn a string specifying either a username or UID into an actual
+ * uid_t for use in setuid(). A string is assumed to be a UID if
+ * it contains only decimal digits. */
+uid_t
+parse_uid(char *user, char *argv0)
+{
+    char		*probe = user;
+    struct passwd	*ent;
+
+    while (*probe && isdigit(*probe)) {
+	probe++;
+    }
+    if (!(*probe)) {
+	return atoi(user);
+    }
+    if (!(ent = getpwnam(user))) {
+	fprintf(stderr, "%s: Bad username %s\n", argv0, user);
+	exit(1);
+    }
+    return (ent->pw_uid);
+}
+
+
+/* Turn a string specifying either a group name or GID into an actual
+ * gid_t for use in setgid(). A string is assumed to be a GID if
+ * it contains only decimal digits. */
+gid_t
+parse_gid(char *group, char *argv0)
+{
+    char		*probe = group;
+    struct group	*ent;
+
+    while (*probe && isdigit(*probe)) {
+	probe++;
+    }
+    if (!(*probe)) {
+	return atoi(group);
+    }
+    if (!(ent = getgrnam(group))) {
+	fprintf(stderr, "%s: Bad group name %s\n", argv0, group);
+	exit(1);
+    }
+    return (ent->gr_gid);
+}
+#endif /* _WIN32 */
diff -Naur src/cronoutils.h src/cronoutils.h
--- src/cronoutils.h	Thu May  3 17:40:12 2001
+++ src/cronoutils.h	Mon Jun  3 00:38:32 2002
@@ -84,6 +84,8 @@
 #include <limits.h>
 #ifndef _WIN32
 #include <unistd.h>
+#include <pwd.h>
+#include <grp.h>
 #else
 #include <io.h>
 #include <direct.h>
@@ -172,7 +174,8 @@
 void		print_debug_msg(char *msg, ...);
 time_t		parse_time(char *time_str, int);
 char 		*timestamp(time_t thetime);
-
+uid_t		parse_uid(char *user, char *argv0);
+gid_t		parse_gid(char *group, char *argv0);
 
 /* Global variables */