Allow daemon running as root to accept --user option, that accepts "user:group" string as input. Performs sanity check on the input, and store the converted uid and gid.
daemon_become_new_user() needs to be called to make the actual switch. Signed-off-by: Andy Zhou <az...@nicira.com> --- v2 : use sysconf() to get proper buffer size. not hard code it --- lib/daemon-unix.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ lib/daemon.h | 27 ++++++++++++++----- 2 files changed, 97 insertions(+), 7 deletions(-) diff --git a/lib/daemon-unix.c b/lib/daemon-unix.c index 4a2e7b4..ee1761a 100644 --- a/lib/daemon-unix.c +++ b/lib/daemon-unix.c @@ -20,6 +20,7 @@ #include <errno.h> #include <fcntl.h> #include <grp.h> +#include <pwd.h> #include <signal.h> #include <stdlib.h> #include <string.h> @@ -693,6 +694,82 @@ should_service_stop(void) return false; } +void daemon_set_new_user(const char *user_spec) +{ + char *pos = strchr(user_spec, ':'); + int bufsize; + + uid = getuid(); + gid = getgid(); + + if (gid || uid) { + VLOG_FATAL("%s: only root can use --user option", pidfile); + } + + if ((bufsize = sysconf(_SC_GETPW_R_SIZE_MAX)) == -1) { + VLOG_FATAL("%s: Invalid --user option %s (Unknown system password " + "configuration)", pidfile, user_spec); + } + + user_spec += strspn(user_spec, " \t\r\n"); + int len = pos ? pos - user_spec : strlen(user_spec); + struct passwd pwd, *res; + char buf[bufsize]; + + if (len) { + user = xzalloc(len + 1); + strncpy(user, user_spec, len); + + if (getpwnam_r(user, &pwd, buf, bufsize, &res)) { + VLOG_FATAL("%s: Invalid --user option %s (no such user %s)", + pidfile, user_spec, user); + } + } else { + /* User is not specified, use current user. */ + if (getpwuid_r(uid, &pwd, buf, bufsize, &res)) { + VLOG_FATAL("%s: Invalid --user option %s (failed to lookup " + "current user with uid %d)", pidfile, user_spec, uid); + } + user = strdup(pwd.pw_name); + } + + uid = pwd.pw_uid; + gid = pwd.pw_gid; + + if (pos) { + char *grpstr = pos + 1; + grpstr += strspn(grpstr, " \t\r\n"); + + if (*grpstr) { + struct group grp, *res; + + if(getgrnam_r(grpstr, &grp, buf, bufsize, &res)) { + VLOG_FATAL("%s: Invalid --user option %s (unknown group %s)", + pidfile, user_spec, grpstr); + } + + if(gid != grp.gr_gid) { + char **mem; + + for(mem = grp.gr_mem; *mem; ++mem) { + if (!strcmp(*mem, user)) { + break; + } + } + + if (!*mem) { + VLOG_FATAL("%s: Invalid --user option %s (user %s is " + "not in group %s)", pidfile, user_spec, + user, grpstr); + } + gid = grp.gr_gid; + } + } + } + + switch_to_new_user = true; +} + void daemon_become_new_user(void) { diff --git a/lib/daemon.h b/lib/daemon.h index ccf30f8..b00c698 100644 --- a/lib/daemon.h +++ b/lib/daemon.h @@ -42,14 +42,16 @@ OPT_NO_CHDIR, \ OPT_OVERWRITE_PIDFILE, \ OPT_PIDFILE, \ - OPT_MONITOR + OPT_MONITOR, \ + OPT_USER_GROUP -#define DAEMON_LONG_OPTIONS \ - {"detach", no_argument, NULL, OPT_DETACH}, \ - {"no-chdir", no_argument, NULL, OPT_NO_CHDIR}, \ - {"pidfile", optional_argument, NULL, OPT_PIDFILE}, \ +#define DAEMON_LONG_OPTIONS \ + {"detach", no_argument, NULL, OPT_DETACH}, \ + {"no-chdir", no_argument, NULL, OPT_NO_CHDIR}, \ + {"pidfile", optional_argument, NULL, OPT_PIDFILE}, \ {"overwrite-pidfile", no_argument, NULL, OPT_OVERWRITE_PIDFILE}, \ - {"monitor", no_argument, NULL, OPT_MONITOR} + {"monitor", no_argument, NULL, OPT_MONITOR}, \ + {"user", required_argument, NULL, OPT_USER_GROUP} #define DAEMON_OPTION_HANDLERS \ case OPT_DETACH: \ @@ -70,6 +72,10 @@ \ case OPT_MONITOR: \ daemon_set_monitor(); \ + break; \ + \ + case OPT_USER_GROUP: \ + daemon_set_new_user(optarg); \ break; void set_detach(void); @@ -77,6 +83,7 @@ void daemon_set_monitor(void); void set_no_chdir(void); void ignore_existing_pidfile(void); void daemon_become_new_user(void); +void daemon_set_new_user(const char *); pid_t read_pidfile(const char *name); #else #define DAEMON_OPTION_ENUMS \ @@ -85,7 +92,7 @@ pid_t read_pidfile(const char *name); OPT_PIDFILE, \ OPT_PIPE_HANDLE, \ OPT_SERVICE, \ - OPT_SERVICE_MONITOR + OPT_SERVICE_MONITOR \ #define DAEMON_LONG_OPTIONS \ {"detach", no_argument, NULL, OPT_DETACH}, \ @@ -120,6 +127,12 @@ void control_handler(DWORD request); void set_pipe_handle(const char *pipe_handle); static inline void +daemon_set_new_user(const char *) +{ + /* Not implemented. */ +} + +static inline void daemon_become_new_user(void) { /* Not implemented. */ -- 1.9.1 _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev