/* * options.c - handles option processing for PPP. * * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The name "Carnegie Mellon University" must not be used to * endorse or promote products derived from this software without * prior written permission. For permission or any legal * details, please contact * Office of Technology Transfer * Carnegie Mellon University * 5000 Forbes Avenue * Pittsburgh, PA 15213-3890 * (412) 268-4387, fax: (412) 268-7395 * tech-transfer@andrew.cmu.edu * * 4. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by Computing Services * at Carnegie Mellon University (http://www.cmu.edu/computing/)." * * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #ifdef PPP_WITH_PLUGINS #include #endif #ifdef PPP_WITH_FILTER #include /* * There have been 3 or 4 different names for this in libpcap CVS, but * this seems to be what they have settled on... * For older versions of libpcap, use DLT_PPP - but that means * we lose the inbound and outbound qualifiers. */ #ifndef DLT_PPP_PPPD #ifdef DLT_PPP_WITHDIRECTION #define DLT_PPP_PPPD DLT_PPP_WITHDIRECTION #else #define DLT_PPP_PPPD DLT_PPP #endif #endif #endif /* PPP_WITH_FILTER */ #include "pppd-private.h" #include "options.h" #include "upap.h" #include "pathnames.h" #if defined(ultrix) || defined(NeXT) char *strdup(char *); #endif struct option_value { struct option_value *next; const char *source; char value[1]; }; /* * Option variables and default values. */ int debug = 0; /* Debug flag */ int kdebugflag = 0; /* Tell kernel to print debug messages */ int default_device = 1; /* Using /dev/tty or equivalent */ bool nodetach = 0; /* Don't detach from controlling tty */ bool updetach = 0; /* Detach once link is up */ bool master_detach; /* Detach when we're (only) multilink master */ #ifdef SYSTEMD bool up_sdnotify = 0; /* Notify systemd once link is up */ #endif int maxconnect = 0; /* Maximum connect time */ char user[MAXNAMELEN]; /* Username for PAP */ char passwd[MAXSECRETLEN]; /* Password for PAP */ bool persist = 0; /* Reopen link after it goes down */ char our_name[MAXNAMELEN]; /* Our name for authentication purposes */ bool demand = 0; /* do dial-on-demand */ int idle_time_limit = 0; /* Disconnect if idle for this many seconds */ int holdoff = 30; /* # seconds to pause before reconnecting */ bool holdoff_specified; /* true if a holdoff value has been given */ int log_to_fd = 1; /* send log messages to this fd too */ bool log_default = 1; /* log_to_fd is default (stdout) */ int maxfail = 10; /* max # of unsuccessful connection attempts */ char linkname[MAXPATHLEN]; /* logical name for link */ bool tune_kernel; /* may alter kernel settings */ int connect_delay = 1000; /* wait this many ms after connect script */ int req_unit = -1; /* requested interface unit */ char path_ipup[MAXPATHLEN]; /* pathname of ip-up script */ char path_ipdown[MAXPATHLEN];/* pathname of ip-down script */ char req_ifname[IFNAMSIZ]; /* requested interface name */ bool multilink = 0; /* Enable multilink operation */ char *bundle_name = NULL; /* bundle name for multilink */ bool dump_options; /* print out option values */ bool show_options; /* print all supported options and exit */ bool dryrun; /* print out option values and exit */ char *domain; /* domain name set by domain option */ int child_wait = 5; /* # seconds to wait for children at exit */ struct userenv *userenv_list; /* user environment variables */ int dfl_route_metric = -1; /* metric of the default route to set over the PPP link */ #ifdef PPP_WITH_IPV6CP char path_ipv6up[MAXPATHLEN]; /* pathname of ipv6-up script */ char path_ipv6down[MAXPATHLEN]; /* pathname of ipv6-down script */ #endif unsigned int maxoctets = 0; /* default - no limit */ session_limit_dir_t maxoctets_dir = PPP_OCTETS_DIRECTION_SUM; /* default - sum of traffic */ int maxoctets_timeout = 1; /* default 1 second */ extern struct option auth_options[]; extern struct stat devstat; #ifdef PPP_WITH_FILTER struct bpf_program pass_filter;/* Filter program for packets to pass */ struct bpf_program active_filter; /* Filter program for link-active pkts */ #endif static struct option *curopt; /* pointer to option being processed */ char *current_option; /* the name of the option being parsed */ int privileged_option; /* set iff the current option came from root */ char *option_source; /* string saying where the option came from */ int option_priority = OPRIO_CFGFILE; /* priority of the current options */ bool devnam_fixed; /* can no longer change device name */ static int logfile_fd = -1; /* fd opened for log file */ static char logfile_name[MAXPATHLEN]; /* name of log file */ static bool noipx_opt; /* dummy for noipx option */ /* * Prototypes */ static int setdomain(char **); static int readfile(char **); static int callfile(char **); static int showversion(char **); static int showhelp(char **); static void usage(void); static int setlogfile(char **); #ifdef PPP_WITH_PLUGINS static int loadplugin(char **); #endif #ifdef PPP_WITH_FILTER static int setpassfilter(char **); static int setactivefilter(char **); #endif static int setmodir(char **); static int user_setenv(char **); static void user_setprint(struct option *, printer_func, void *); static int user_unsetenv(char **); static void user_unsetprint(struct option *, printer_func, void *); static struct option *find_option(char *name); static int process_option(struct option *, char *, char **); static int n_arguments(struct option *); static int number_option(char *, u_int32_t *, int); /* * Structure to store extra lists of options. */ struct option_list { struct option *options; struct option_list *next; }; static struct option_list *extra_options = NULL; /* * Valid arguments. */ struct option general_options[] = { { "debug", o_int, &debug, "Increase debugging level", OPT_INC | OPT_NOARG | 1 }, { "-d", o_int, &debug, "Increase debugging level", OPT_ALIAS | OPT_INC | OPT_NOARG | 1 }, { "kdebug", o_int, &kdebugflag, "Set kernel driver debug level", OPT_PRIO }, { "nodetach", o_bool, &nodetach, "Don't detach from controlling tty", OPT_PRIO | 1 }, { "-detach", o_bool, &nodetach, "Don't detach from controlling tty", OPT_ALIAS | OPT_PRIOSUB | 1 }, #ifdef SYSTEMD { "up_sdnotify", o_bool, &up_sdnotify, "Notify systemd once link is up (implies nodetach)", OPT_PRIOSUB | OPT_A2COPY | 1, &nodetach }, #endif { "updetach", o_bool, &updetach, "Detach from controlling tty once link is up", OPT_PRIOSUB | OPT_A2CLR | 1, &nodetach }, { "master_detach", o_bool, &master_detach, "Detach when we're multilink master but have no link", 1 }, { "holdoff", o_int, &holdoff, "Set time in seconds before retrying connection", OPT_PRIO, &holdoff_specified }, { "idle", o_int, &idle_time_limit, "Set time in seconds before disconnecting idle link", OPT_PRIO }, { "maxconnect", o_int, &maxconnect, "Set connection time limit", OPT_PRIO | OPT_LLIMIT | OPT_NOINCR | OPT_ZEROINF }, { "domain", o_special, (void *)setdomain, "Add given domain name to hostname", OPT_PRIO | OPT_PRIV | OPT_A2STRVAL, &domain }, { "file", o_special, (void *)readfile, "Take options from a file", OPT_NOPRINT }, { "call", o_special, (void *)callfile, "Take options from a privileged file", OPT_NOPRINT }, { "persist", o_bool, &persist, "Keep on reopening connection after close", OPT_PRIO | 1 }, { "nopersist", o_bool, &persist, "Turn off persist option", OPT_PRIOSUB }, { "demand", o_bool, &demand, "Dial on demand", OPT_INITONLY | 1, &persist }, { "--version", o_special_noarg, (void *)showversion, "Show version number" }, { "-v", o_special_noarg, (void *)showversion, "Show version number" }, { "show-options", o_bool, &show_options, "Show all options and exit", 1 }, { "--help", o_special_noarg, (void *)showhelp, "Show brief listing of options" }, { "-h", o_special_noarg, (void *)showhelp, "Show brief listing of options", OPT_ALIAS }, { "logfile", o_special, (void *)setlogfile, "Append log messages to this file", OPT_PRIO | OPT_A2STRVAL | OPT_STATIC, &logfile_name }, { "logfd", o_int, &log_to_fd, "Send log messages to this file descriptor", OPT_PRIOSUB | OPT_A2CLR, &log_default }, { "nolog", o_int, &log_to_fd, "Don't send log messages to any file", OPT_PRIOSUB | OPT_NOARG | OPT_VAL(-1) }, { "nologfd", o_int, &log_to_fd, "Don't send log messages to any file descriptor", OPT_PRIOSUB | OPT_ALIAS | OPT_NOARG | OPT_VAL(-1) }, { "linkname", o_string, linkname, "Set logical name for link", OPT_PRIO | OPT_PRIV | OPT_STATIC, NULL, MAXPATHLEN }, { "maxfail", o_int, &maxfail, "Maximum number of unsuccessful connection attempts to allow", OPT_PRIO }, { "ktune", o_bool, &tune_kernel, "Alter kernel settings as necessary", OPT_PRIO | 1 }, { "noktune", o_bool, &tune_kernel, "Don't alter kernel settings", OPT_PRIOSUB }, { "connect-delay", o_int, &connect_delay, "Maximum time (in ms) to wait after connect script finishes", OPT_PRIO }, { "unit", o_int, &req_unit, "PPP interface unit number to use if possible", OPT_PRIO | OPT_LLIMIT, 0, 0 }, { "ifname", o_string, req_ifname, "Set PPP interface name", OPT_PRIO | OPT_PRIV | OPT_STATIC, NULL, IFNAMSIZ }, { "dump", o_bool, &dump_options, "Print out option values after parsing all options", 1 }, { "dryrun", o_bool, &dryrun, "Stop after parsing, printing, and checking options", 1 }, { "child-timeout", o_int, &child_wait, "Number of seconds to wait for child processes at exit", OPT_PRIO }, { "set", o_special, (void *)user_setenv, "Set user environment variable", OPT_A2PRINTER | OPT_NOPRINT, (void *)user_setprint }, { "unset", o_special, (void *)user_unsetenv, "Unset user environment variable", OPT_A2PRINTER | OPT_NOPRINT, (void *)user_unsetprint }, { "defaultroute-metric", o_int, &dfl_route_metric, "Metric to use for the default route (Linux only; -1 for default behavior)", OPT_PRIV|OPT_LLIMIT|OPT_INITONLY, NULL, 0, -1 }, { "ip-up-script", o_string, path_ipup, "Set pathname of ip-up script", OPT_PRIV|OPT_STATIC, NULL, MAXPATHLEN }, { "ip-down-script", o_string, path_ipdown, "Set pathname of ip-down script", OPT_PRIV|OPT_STATIC, NULL, MAXPATHLEN }, #ifdef PPP_WITH_IPV6CP { "ipv6-up-script", o_string, path_ipv6up, "Set pathname of ipv6-up script", OPT_PRIV|OPT_STATIC, NULL, MAXPATHLEN }, { "ipv6-down-script", o_string, path_ipv6down, "Set pathname of ipv6-down script", OPT_PRIV|OPT_STATIC, NULL, MAXPATHLEN }, #endif #ifdef PPP_WITH_MULTILINK { "multilink", o_bool, &multilink, "Enable multilink operation", OPT_PRIO | 1 }, { "mp", o_bool, &multilink, "Enable multilink operation", OPT_PRIOSUB | OPT_ALIAS | 1 }, { "nomultilink", o_bool, &multilink, "Disable multilink operation", OPT_PRIOSUB | 0 }, { "nomp", o_bool, &multilink, "Disable multilink operation", OPT_PRIOSUB | OPT_ALIAS | 0 }, { "bundle", o_string, &bundle_name, "Bundle name for multilink", OPT_PRIO }, #endif /* PPP_WITH_MULTILINK */ #ifdef PPP_WITH_PLUGINS { "plugin", o_special, (void *)loadplugin, "Load a plug-in module into pppd", OPT_PRIV | OPT_A2LIST }, #endif #ifdef PPP_WITH_FILTER { "pass-filter", o_special, setpassfilter, "set filter for packets to pass", OPT_PRIO }, { "active-filter", o_special, setactivefilter, "set filter for active pkts", OPT_PRIO }, #endif { "maxoctets", o_int, &maxoctets, "Set connection traffic limit", OPT_PRIO | OPT_LLIMIT | OPT_NOINCR | OPT_ZEROINF }, { "mo", o_int, &maxoctets, "Set connection traffic limit", OPT_ALIAS | OPT_PRIO | OPT_LLIMIT | OPT_NOINCR | OPT_ZEROINF }, { "mo-direction", o_special, setmodir, "Set direction for limit traffic (sum,in,out,max)" }, { "mo-timeout", o_int, &maxoctets_timeout, "Check for traffic limit every N seconds", OPT_PRIO | OPT_LLIMIT | 1 }, /* Dummy option, does nothing */ { "noipx", o_bool, &noipx_opt, NULL, OPT_NOPRINT | 1 }, { NULL } }; #ifndef IMPLEMENTATION #define IMPLEMENTATION "" #endif int ppp_get_max_idle_time() { return idle_time_limit; } void ppp_set_max_idle_time(unsigned int max) { idle_time_limit = max; } int ppp_get_max_connect_time() { return maxconnect; } void ppp_set_max_connect_time(unsigned int max) { maxconnect = max; } void ppp_set_session_limit(unsigned int octets) { maxoctets = octets; } void ppp_set_session_limit_dir(unsigned int dir) { if (dir > 4) dir = PPP_OCTETS_DIRECTION_SUM; maxoctets_dir = (session_limit_dir_t) dir; } bool debug_on() { return !!debug; } int ppp_get_path(ppp_path_t type, char *buf, size_t bufsz) { const char *path; if (buf && bufsz > 0) { switch (type) { case PPP_DIR_LOG: path = PPP_PATH_VARLOG; break; case PPP_DIR_RUNTIME: path = PPP_PATH_VARRUN; break; #ifdef PPP_WITH_PLUGINS case PPP_DIR_PLUGIN: path = PPP_PATH_PLUGIN; break; #endif case PPP_DIR_CONF: path = PPP_PATH_CONFDIR; break; } return strlcpy(buf, path, bufsz); } return -1; } int ppp_get_filepath(ppp_path_t type, const char *name, char *buf, size_t bufsz) { const char *path; if (buf && bufsz > 0) { switch (type) { case PPP_DIR_LOG: path = PPP_PATH_VARLOG; break; case PPP_DIR_RUNTIME: path = PPP_PATH_VARRUN; break; #ifdef PPP_WITH_PLUGINS case PPP_DIR_PLUGIN: path = PPP_PATH_PLUGIN; break; #endif case PPP_DIR_CONF: path = PPP_PATH_CONFDIR; break; } return slprintf(buf, bufsz, "%s/%s", path, name); } return -1; } bool ppp_persist() { return !!persist; } /* * parse_args - parse a string of arguments from the command line. */ int parse_args(int argc, char **argv) { char *arg; struct option *opt; int n; privileged_option = privileged; option_source = "command line"; option_priority = OPRIO_CMDLINE; while (argc > 0) { arg = *argv++; --argc; opt = find_option(arg); if (opt == NULL) { ppp_option_error("unrecognized option '%s'", arg); usage(); return 0; } n = n_arguments(opt); if (argc < n) { ppp_option_error("too few parameters for option %s", arg); return 0; } if (!process_option(opt, arg, argv)) return 0; argc -= n; argv += n; } return 1; } /* * options_from_file - Read a string of options from a file, * and interpret them. */ int ppp_options_from_file(char *filename, int must_exist, int check_prot, int priv) { FILE *f; int i, newline, ret, err; struct option *opt; int oldpriv, n; char *oldsource; uid_t euid; char *argv[MAXARGS]; char args[MAXARGS][MAXWORDLEN]; char cmd[MAXWORDLEN]; euid = geteuid(); if (check_prot && seteuid(getuid()) == -1) { ppp_option_error("unable to drop privileges to open %s: %m", filename); return 0; } f = fopen(filename, "r"); err = errno; if (check_prot && seteuid(euid) == -1) fatal("unable to regain privileges"); if (f == NULL) { errno = err; if (!must_exist) { if (err != ENOENT && err != ENOTDIR) warn("Warning: can't open options file %s: %m", filename); return 1; } ppp_option_error("Can't open options file %s: %m", filename); return 0; } oldpriv = privileged_option; privileged_option = priv; oldsource = option_source; option_source = strdup(filename); if (option_source == NULL) option_source = "file"; ret = 0; while (getword(f, cmd, &newline, filename)) { opt = find_option(cmd); if (opt == NULL) { ppp_option_error("In file %s: unrecognized option '%s'", filename, cmd); goto err; } n = n_arguments(opt); for (i = 0; i < n; ++i) { if (!getword(f, args[i], &newline, filename)) { ppp_option_error( "In file %s: too few parameters for option '%s'", filename, cmd); goto err; } argv[i] = args[i]; } if (!process_option(opt, cmd, argv)) goto err; } ret = 1; err: fclose(f); privileged_option = oldpriv; option_source = oldsource; return ret; } /* * options_from_user - See if the use has a ~/.ppprc file, * and if so, interpret options from it. */ int options_from_user(void) { char *user, *path, *file; int ret; struct passwd *pw; size_t pl; pw = getpwuid(getuid()); if (pw == NULL || (user = pw->pw_dir) == NULL || user[0] == 0) return 1; file = PPP_PATH_USEROPT; pl = strlen(user) + strlen(file) + 2; path = malloc(pl); if (path == NULL) novm("init file name"); slprintf(path, pl, "%s/%s", user, file); option_priority = OPRIO_CFGFILE; ret = ppp_options_from_file(path, 0, 1, privileged); free(path); return ret; } /* * options_for_tty - See if an options file exists for the serial * device, and if so, interpret options from it. * We only allow the per-tty options file to override anything from * the command line if it is something that the user can't override * once it has been set by root; this is done by giving configuration * files a lower priority than the command line. */ int options_for_tty(void) { char *dev, *path, *p; int ret; size_t pl; dev = devnam; if ((p = strstr(dev, "/dev/")) != NULL) dev = p + 5; if (dev[0] == 0 || strcmp(dev, "tty") == 0) return 1; /* don't look for /etc/ppp/options.tty */ pl = strlen(PPP_PATH_TTYOPT) + strlen(dev) + 1; path = malloc(pl); if (path == NULL) novm("tty init file name"); slprintf(path, pl, "%s%s", PPP_PATH_TTYOPT, dev); /* Turn slashes into dots, for Solaris case (e.g. /dev/term/a) */ for (p = path + strlen(PPP_PATH_TTYOPT); *p != 0; ++p) if (*p == '/') *p = '.'; option_priority = OPRIO_CFGFILE; ret = ppp_options_from_file(path, 0, 0, 1); free(path); return ret; } /* * options_from_list - process a string of options in a wordlist. */ int options_from_list(struct wordlist *w, int priv) { char *argv[MAXARGS]; struct option *opt; int i, n, ret = 0; struct wordlist *w0; privileged_option = priv; option_source = "secrets file"; option_priority = OPRIO_SECFILE; while (w != NULL) { opt = find_option(w->word); if (opt == NULL) { ppp_option_error("In secrets file: unrecognized option '%s'", w->word); goto err; } n = n_arguments(opt); w0 = w; for (i = 0; i < n; ++i) { w = w->next; if (w == NULL) { ppp_option_error( "In secrets file: too few parameters for option '%s'", w0->word); goto err; } argv[i] = w->word; } if (!process_option(opt, w0->word, argv)) goto err; w = w->next; } ret = 1; err: return ret; } /* * match_option - see if this option matches an option structure. */ static int match_option(char *name, struct option *opt, int dowild) { int (*match)(char *, char **, int); if (dowild != (opt->type == o_wild)) return 0; if (!dowild) return strcmp(name, opt->name) == 0; match = (int (*)(char *, char **, int)) opt->addr; return (*match)(name, NULL, 0); } /* * find_option - scan the option lists for the various protocols * looking for an entry with the given name. * This could be optimized by using a hash table. */ static struct option * find_option(char *name) { struct option *opt; struct option_list *list; int i, dowild; for (dowild = 0; dowild <= 1; ++dowild) { for (opt = general_options; opt->name != NULL; ++opt) if (match_option(name, opt, dowild)) return opt; for (opt = auth_options; opt->name != NULL; ++opt) if (match_option(name, opt, dowild)) return opt; for (list = extra_options; list != NULL; list = list->next) for (opt = list->options; opt->name != NULL; ++opt) if (match_option(name, opt, dowild)) return opt; for (opt = the_channel->options; opt->name != NULL; ++opt) if (match_option(name, opt, dowild)) return opt; for (i = 0; protocols[i] != NULL; ++i) if ((opt = protocols[i]->options) != NULL) for (; opt->name != NULL; ++opt) if (match_option(name, opt, dowild)) return opt; } return NULL; } /* * process_option - process one new-style option. */ static int process_option(struct option *opt, char *cmd, char **argv) { u_int32_t v; int iv, a; char *sv; int (*parser)(char **); int (*wildp)(char *, char **, int); char *optopt = (opt->type == o_wild)? "": " option"; int prio = option_priority; struct option *mainopt = opt; current_option = opt->name; if ((opt->flags & OPT_PRIVFIX) && privileged_option) prio += OPRIO_ROOT; while (mainopt->flags & OPT_PRIOSUB) --mainopt; if (mainopt->flags & OPT_PRIO) { if (prio < mainopt->priority) { /* new value doesn't override old */ if (prio == OPRIO_CMDLINE && mainopt->priority > OPRIO_ROOT) { ppp_option_error("%s%s set in %s cannot be overridden\n", opt->name, optopt, mainopt->source); return 0; } return 1; } if (prio > OPRIO_ROOT && mainopt->priority == OPRIO_CMDLINE) warn("%s%s from %s overrides command line", opt->name, optopt, option_source); } if ((opt->flags & OPT_INITONLY) && !in_phase(PHASE_INITIALIZE)) { ppp_option_error("%s%s cannot be changed after initialization", opt->name, optopt); return 0; } if ((opt->flags & OPT_PRIV) && !privileged_option) { ppp_option_error("using the %s%s requires root privilege", opt->name, optopt); return 0; } if ((opt->flags & OPT_ENABLE) && *(bool *)(opt->addr2) == 0) { ppp_option_error("%s%s is disabled", opt->name, optopt); return 0; } if ((opt->flags & OPT_DEVEQUIV) && devnam_fixed) { ppp_option_error("the %s%s may not be changed in %s", opt->name, optopt, option_source); return 0; } switch (opt->type) { case o_bool: v = opt->flags & OPT_VALUE; *(bool *)(opt->addr) = v; if (opt->addr2 && (opt->flags & OPT_A2COPY)) *(bool *)(opt->addr2) = v; else if (opt->addr2 && (opt->flags & OPT_A2CLR)) *(bool *)(opt->addr2) = 0; else if (opt->addr2 && (opt->flags & OPT_A2CLRB)) *(u_char *)(opt->addr2) &= ~v; else if (opt->addr2 && (opt->flags & OPT_A2OR)) *(u_char *)(opt->addr2) |= v; break; case o_int: iv = 0; if ((opt->flags & OPT_NOARG) == 0) { if (!ppp_int_option(*argv, &iv)) return 0; if ((((opt->flags & OPT_LLIMIT) && iv < opt->lower_limit) || ((opt->flags & OPT_ULIMIT) && iv > opt->upper_limit)) && !((opt->flags & OPT_ZEROOK && iv == 0))) { char *zok = (opt->flags & OPT_ZEROOK)? " zero or": ""; switch (opt->flags & OPT_LIMITS) { case OPT_LLIMIT: ppp_option_error("%s value must be%s >= %d", opt->name, zok, opt->lower_limit); break; case OPT_ULIMIT: ppp_option_error("%s value must be%s <= %d", opt->name, zok, opt->upper_limit); break; case OPT_LIMITS: ppp_option_error("%s value must be%s between %d and %d", opt->name, zok, opt->lower_limit, opt->upper_limit); break; } return 0; } } a = opt->flags & OPT_VALUE; if (a >= 128) a -= 256; /* sign extend */ iv += a; if (opt->flags & OPT_INC) iv += *(int *)(opt->addr); if ((opt->flags & OPT_NOINCR) && !privileged_option) { int oldv = *(int *)(opt->addr); if ((opt->flags & OPT_ZEROINF) ? (oldv != 0 && (iv == 0 || iv > oldv)) : (iv > oldv)) { ppp_option_error("%s value cannot be increased", opt->name); return 0; } } *(int *)(opt->addr) = iv; if (opt->addr2 && (opt->flags & OPT_A2COPY)) *(int *)(opt->addr2) = iv; break; case o_uint32: if (opt->flags & OPT_NOARG) { v = opt->flags & OPT_VALUE; if (v & 0x80) v |= 0xffffff00U; } else if (!number_option(*argv, &v, 16)) return 0; if (opt->flags & OPT_OR) v |= *(u_int32_t *)(opt->addr); *(u_int32_t *)(opt->addr) = v; if (opt->addr2 && (opt->flags & OPT_A2COPY)) *(u_int32_t *)(opt->addr2) = v; break; case o_string: if (opt->flags & OPT_STATIC) { strlcpy((char *)(opt->addr), *argv, opt->upper_limit); } else { char **optptr = (char **)(opt->addr); sv = strdup(*argv); if (sv == NULL) novm("option argument"); if (*optptr) free(*optptr); *optptr = sv; } /* obfuscate original argument for things like password */ if (opt->flags & OPT_HIDE) { memset(*argv, '?', strlen(*argv)); *argv = "********"; } break; case o_special_noarg: case o_special: parser = (int (*)(char **)) opt->addr; curopt = opt; if (!(*parser)(argv)) return 0; if (opt->flags & OPT_A2LIST) { struct option_value *ovp, *pp; ovp = malloc(sizeof(*ovp) + strlen(*argv)); if (ovp != 0) { strcpy(ovp->value, *argv); ovp->source = option_source; ovp->next = NULL; if (opt->addr2 == NULL) { opt->addr2 = ovp; } else { for (pp = opt->addr2; pp->next != NULL; pp = pp->next) ; pp->next = ovp; } } } break; case o_wild: wildp = (int (*)(char *, char **, int)) opt->addr; if (!(*wildp)(cmd, argv, 1)) return 0; break; } /* * If addr2 wasn't used by any flag (OPT_A2COPY, etc.) but is set, * treat it as a bool and set/clear it based on the OPT_A2CLR bit. */ if (opt->addr2 && (opt->flags & (OPT_A2COPY|OPT_ENABLE |OPT_A2PRINTER|OPT_A2STRVAL|OPT_A2LIST|OPT_A2OR)) == 0) *(bool *)(opt->addr2) = !(opt->flags & OPT_A2CLR); mainopt->source = option_source; mainopt->priority = prio; mainopt->winner = opt - mainopt; return 1; } /* * override_value - if the option priorities would permit us to * override the value of option, return 1 and update the priority * and source of the option value. Otherwise returns 0. */ int override_value(char *option, int priority, const char *source) { struct option *opt; opt = find_option(option); if (opt == NULL) return 0; while (opt->flags & OPT_PRIOSUB) --opt; if ((opt->flags & OPT_PRIO) && priority < opt->priority) return 0; opt->priority = priority; opt->source = source; opt->winner = -1; return 1; } /* * n_arguments - tell how many arguments an option takes */ static int n_arguments(struct option *opt) { return (opt->type == o_bool || opt->type == o_special_noarg || (opt->flags & OPT_NOARG))? 0: 1; } /* * add_options - add a list of options to the set we grok. */ void ppp_add_options(struct option *opt) { struct option_list *list; list = malloc(sizeof(*list)); if (list == 0) novm("option list entry"); list->options = opt; list->next = extra_options; extra_options = list; } /* * check_options - check that options are valid and consistent. */ void check_options(void) { if (logfile_fd >= 0 && logfile_fd != log_to_fd) close(logfile_fd); } /* * print_option - print out an option and its value */ static void print_option(struct option *opt, struct option *mainopt, printer_func printer, void *arg) { int i, v; char *p; if (opt->flags & OPT_NOPRINT) return; switch (opt->type) { case o_bool: v = opt->flags & OPT_VALUE; if (*(bool *)opt->addr != v) /* this can happen legitimately, e.g. lock option turned off for default device */ break; printer(arg, "%s", opt->name); break; case o_int: v = opt->flags & OPT_VALUE; if (v >= 128) v -= 256; i = *(int *)opt->addr; if (opt->flags & OPT_NOARG) { printer(arg, "%s", opt->name); if (i != v) { if (opt->flags & OPT_INC) { for (; i > v; i -= v) printer(arg, " %s", opt->name); } else printer(arg, " # oops: %d not %d\n", i, v); } } else { printer(arg, "%s %d", opt->name, i); } break; case o_uint32: printer(arg, "%s", opt->name); if ((opt->flags & OPT_NOARG) == 0) printer(arg, " %x", *(u_int32_t *)opt->addr); break; case o_string: if (opt->flags & OPT_HIDE) { p = "??????"; } else { p = (char *) opt->addr; if ((opt->flags & OPT_STATIC) == 0) p = *(char **)p; } printer(arg, "%s %q", opt->name, p); break; case o_special: case o_special_noarg: case o_wild: if (opt->type != o_wild) { printer(arg, "%s", opt->name); if (n_arguments(opt) == 0) break; printer(arg, " "); } if (opt->flags & OPT_A2PRINTER) { void (*oprt)(struct option *, printer_func, void *); oprt = (void (*)(struct option *, printer_func, void *)) opt->addr2; (*oprt)(opt, printer, arg); } else if (opt->flags & OPT_A2STRVAL) { p = (char *) opt->addr2; if ((opt->flags & OPT_STATIC) == 0) p = *(char **)p; printer(arg, "%q", p); } else if (opt->flags & OPT_A2LIST) { struct option_value *ovp; ovp = (struct option_value *) opt->addr2; for (;;) { printer(arg, "%q", ovp->value); if ((ovp = ovp->next) == NULL) break; printer(arg, "\t\t# (from %s)\n%s ", ovp->source, opt->name); } } else { printer(arg, "xxx # [don't know how to print value]"); } break; default: printer(arg, "# %s value (type %d\?\?)", opt->name, opt->type); break; } printer(arg, "\t\t# (from %s)\n", mainopt->source); } /* * print_option_list - print out options in effect from an * array of options. */ static void print_option_list(struct option *opt, printer_func printer, void *arg) { while (opt->name != NULL) { if (opt->priority != OPRIO_DEFAULT && opt->winner != (short int) -1) print_option(opt + opt->winner, opt, printer, arg); do { ++opt; } while (opt->flags & OPT_PRIOSUB); } } /* * print_options - print out what options are in effect. */ void print_options(printer_func printer, void *arg) { struct option_list *list; int i; printer(arg, "pppd options in effect:\n"); print_option_list(general_options, printer, arg); print_option_list(auth_options, printer, arg); for (list = extra_options; list != NULL; list = list->next) print_option_list(list->options, printer, arg); print_option_list(the_channel->options, printer, arg); for (i = 0; protocols[i] != NULL; ++i) print_option_list(protocols[i]->options, printer, arg); } /* * usage - print out a message telling how to use the program. */ static void usage(void) { FILE *fp = stderr; if (in_phase(PHASE_INITIALIZE)) { fprintf(fp, "%s v%s\n", PACKAGE_NAME, PACKAGE_VERSION); fprintf(fp, "Copyright (C) 1999-2022 Paul Mackerras, and others. All rights reserved.\n\n"); fprintf(fp, "License BSD: The 3 clause BSD license \n"); fprintf(fp, "This is free software: you are free to change and redistribute it.\n"); fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n\n"); fprintf(fp, "Report Bugs:\n %s\n\n", PACKAGE_BUGREPORT); fprintf(fp, "Usage: %s [ options ], where options are:\n", progname); fprintf(fp, " Communicate over the named device\n"); fprintf(fp, " Set the baud rate to \n"); fprintf(fp, " : Set the local and/or remote interface IP\n"); fprintf(fp, " addresses. Either one may be omitted.\n"); fprintf(fp, " asyncmap Set the desired async map to hex \n"); fprintf(fp, " auth Require authentication from peer\n"); fprintf(fp, " connect

Invoke shell command

to set up the serial line\n"); fprintf(fp, " crtscts Use hardware RTS/CTS flow control\n"); fprintf(fp, " defaultroute Add default route through interface\n"); fprintf(fp, " file Take options from file \n"); fprintf(fp, " modem Use modem control lines\n"); fprintf(fp, " mru Set MRU value to for negotiation\n"); fprintf(fp, " show-options Display an extended list of options\n"); fprintf(fp, "See pppd(8) for more options.\n"); } } /* * showhelp - print out usage message and exit. */ static int showhelp(char **argv) { if (in_phase(PHASE_INITIALIZE)) { usage(); exit(0); } return 0; } /* * showversion - print out the version number and exit. */ static int showversion(char **argv) { if (in_phase(PHASE_INITIALIZE)) { fprintf(stdout, "pppd version %s\n", VERSION); exit(0); } return 0; } /* * Print a set of options including the name of the group of options */ static void showopts_list(FILE *fp, const char *title, struct option *list, ...) { struct option *opt = list; va_list varg; if (opt && opt->name) { va_start(varg, list); vfprintf(fp, title, varg); fprintf(fp, ":\n"); va_end(varg); do { fprintf(fp, " %-22s %s\n", opt->name, opt->description?:""); opt++; } while (opt && opt->name); fprintf(fp, "\n"); } } /* * Dumps the list of available options */ void showopts(void) { struct option_list *list; FILE *fp = stderr; int i = 0; showopts_list(fp, "General Options", general_options); showopts_list(fp, "Authentication Options", auth_options); for (list = extra_options; list != NULL; list = list->next) showopts_list(fp, "Extra Options", list->options); showopts_list(fp, "Channel Options", the_channel->options); for (i = 0; protocols[i] != NULL; ++i) { if (protocols[i]->options != NULL) { showopts_list(fp, "%s Options", protocols[i]->options, protocols[i]->name); } } } /* * ppp_option_error - print a message about an error in an option. * The message is logged, and also sent to * stderr if in_phase(PHASE_INITIALIZE). */ void ppp_option_error(char *fmt, ...) { va_list args; char buf[1024]; va_start(args, fmt); vslprintf(buf, sizeof(buf), fmt, args); va_end(args); if (in_phase(PHASE_INITIALIZE)) fprintf(stderr, "%s: %s\n", progname, buf); syslog(LOG_ERR, "%s", buf); } #if 0 /* * readable - check if a file is readable by the real user. */ int readable(int fd) { uid_t uid; int i; struct stat sbuf; uid = getuid(); if (uid == 0) return 1; if (fstat(fd, &sbuf) != 0) return 0; if (sbuf.st_uid == uid) return sbuf.st_mode & S_IRUSR; if (sbuf.st_gid == getgid()) return sbuf.st_mode & S_IRGRP; for (i = 0; i < ngroups; ++i) if (sbuf.st_gid == groups[i]) return sbuf.st_mode & S_IRGRP; return sbuf.st_mode & S_IROTH; } #endif /* * Read a word from a file. * Words are delimited by white-space or by quotes (" or '). * Quotes, white-space and \ may be escaped with \. * \ is ignored. */ int getword(FILE *f, char *word, int *newlinep, char *filename) { int c, len, escape; int quoted, comment; int value, digit, got, n; #define isoctal(c) ((c) >= '0' && (c) < '8') *newlinep = 0; len = 0; escape = 0; comment = 0; quoted = 0; /* * First skip white-space and comments. */ for (;;) { c = getc(f); if (c == EOF) break; /* * A newline means the end of a comment; backslash-newline * is ignored. Note that we cannot have escape && comment. */ if (c == '\n') { if (!escape) { *newlinep = 1; comment = 0; } else escape = 0; continue; } /* * Ignore characters other than newline in a comment. */ if (comment) continue; /* * If this character is escaped, we have a word start. */ if (escape) break; /* * If this is the escape character, look at the next character. */ if (c == '\\') { escape = 1; continue; } /* * If this is the start of a comment, ignore the rest of the line. */ if (c == '#') { comment = 1; continue; } /* * A non-whitespace character is the start of a word. */ if (!isspace(c)) break; } /* * Process characters until the end of the word. */ while (c != EOF) { if (escape) { /* * This character is escaped: backslash-newline is ignored, * various other characters indicate particular values * as for C backslash-escapes. */ escape = 0; if (c == '\n') { c = getc(f); continue; } got = 0; switch (c) { case 'a': value = '\a'; break; case 'b': value = '\b'; break; case 'f': value = '\f'; break; case 'n': value = '\n'; break; case 'r': value = '\r'; break; case 's': value = ' '; break; case 't': value = '\t'; break; default: if (isoctal(c)) { /* * \ddd octal sequence */ value = 0; for (n = 0; n < 3 && isoctal(c); ++n) { value = (value << 3) + (c & 07); c = getc(f); } got = 1; break; } if (c == 'x') { /* * \x sequence */ value = 0; c = getc(f); for (n = 0; n < 2 && isxdigit(c); ++n) { digit = toupper(c) - '0'; if (digit > 10) digit += '0' + 10 - 'A'; value = (value << 4) + digit; c = getc (f); } got = 1; break; } /* * Otherwise the character stands for itself. */ value = c; break; } /* * Store the resulting character for the escape sequence. */ if (len < MAXWORDLEN) { word[len] = value; ++len; } if (!got) c = getc(f); continue; } /* * Backslash starts a new escape sequence. */ if (c == '\\') { escape = 1; c = getc(f); continue; } /* * Not escaped: check for the start or end of a quoted * section and see if we've reached the end of the word. */ if (quoted) { if (c == quoted) { quoted = 0; c = getc(f); continue; } } else if (c == '"' || c == '\'') { quoted = c; c = getc(f); continue; } else if (isspace(c) || c == '#') { ungetc (c, f); break; } /* * An ordinary character: store it in the word and get another. */ if (len < MAXWORDLEN) { word[len] = c; ++len; } c = getc(f); } word[MAXWORDLEN-1] = 0; /* make sure word is null-terminated */ /* * End of the word: check for errors. */ if (c == EOF) { if (ferror(f)) { if (errno == 0) errno = EIO; ppp_option_error("Error reading %s: %m", filename); die(1); } /* * If len is zero, then we didn't find a word before the * end of the file. */ if (len == 0) return 0; if (quoted) ppp_option_error("warning: quoted word runs to end of file (%.20s...)", filename, word); } /* * Warn if the word was too long, and append a terminating null. */ if (len >= MAXWORDLEN) { ppp_option_error("warning: word in file %s too long (%.20s...)", filename, word); len = MAXWORDLEN - 1; } word[len] = 0; return 1; #undef isoctal } /* * number_option - parse an unsigned numeric parameter for an option. */ static int number_option(char *str, u_int32_t *valp, int base) { char *ptr; *valp = strtoul(str, &ptr, base); if (ptr == str) { ppp_option_error("invalid numeric parameter '%s' for %s option", str, current_option); return 0; } return 1; } /* * int_option - like number_option, but valp is int *, * the base is assumed to be 0, and *valp is not changed * if there is an error. */ int ppp_int_option(char *str, int *valp) { u_int32_t v; if (!number_option(str, &v, 0)) return 0; *valp = (int) v; return 1; } /* * The following procedures parse options. */ /* * readfile - take commands from a file. */ static int readfile(char **argv) { return ppp_options_from_file(*argv, 1, 1, privileged_option); } /* * callfile - take commands from /etc/ppp/peers/. * Name may not contain /../, start with / or ../, or end in /.. */ static int callfile(char **argv) { char *fname, *arg, *p; int l, ok; arg = *argv; ok = 1; if (arg[0] == '/' || arg[0] == 0) ok = 0; else { for (p = arg; *p != 0; ) { if (p[0] == '.' && p[1] == '.' && (p[2] == '/' || p[2] == 0)) { ok = 0; break; } while (*p != '/' && *p != 0) ++p; if (*p == '/') ++p; } } if (!ok) { ppp_option_error("call option value may not contain .. or start with /"); return 0; } l = strlen(arg) + strlen(PPP_PATH_PEERFILES) + 1; if ((fname = (char *) malloc(l)) == NULL) novm("call file name"); slprintf(fname, l, "%s%s", PPP_PATH_PEERFILES, arg); ppp_script_setenv("CALL_FILE", arg, 0); ok = ppp_options_from_file(fname, 1, 1, 1); free(fname); return ok; } #ifdef PPP_WITH_FILTER /* * setpassfilter - Set the pass filter for packets */ static int setpassfilter(char **argv) { pcap_t *pc; int ret = 1; pc = pcap_open_dead(DLT_PPP_PPPD, 65535); if (pcap_compile(pc, &pass_filter, *argv, 1, netmask) == -1) { ppp_option_error("error in pass-filter expression: %s\n", pcap_geterr(pc)); ret = 0; } pcap_close(pc); return ret; } /* * setactivefilter - Set the active filter for packets */ static int setactivefilter(char **argv) { pcap_t *pc; int ret = 1; pc = pcap_open_dead(DLT_PPP_PPPD, 65535); if (pcap_compile(pc, &active_filter, *argv, 1, netmask) == -1) { ppp_option_error("error in active-filter expression: %s\n", pcap_geterr(pc)); ret = 0; } pcap_close(pc); return ret; } #endif /* * setdomain - Set domain name to append to hostname */ static int setdomain(char **argv) { gethostname(hostname, MAXNAMELEN); if (**argv != 0) { if (**argv != '.') strncat(hostname, ".", MAXNAMELEN - strlen(hostname)); domain = hostname + strlen(hostname); strncat(hostname, *argv, MAXNAMELEN - strlen(hostname)); } hostname[MAXNAMELEN-1] = 0; return (1); } static int setlogfile(char **argv) { int fd, err; uid_t euid; euid = geteuid(); if (!privileged_option && seteuid(getuid()) == -1) { ppp_option_error("unable to drop permissions to open %s: %m", *argv); return 0; } fd = open(*argv, O_WRONLY | O_APPEND | O_CREAT | O_EXCL, 0644); if (fd < 0 && errno == EEXIST) fd = open(*argv, O_WRONLY | O_APPEND); err = errno; if (!privileged_option && seteuid(euid) == -1) fatal("unable to regain privileges: %m"); if (fd < 0) { errno = err; ppp_option_error("Can't open log file %s: %m", *argv); return 0; } strlcpy(logfile_name, *argv, sizeof(logfile_name)); if (logfile_fd >= 0) close(logfile_fd); logfile_fd = fd; log_to_fd = fd; log_default = 0; return 1; } static int setmodir(char **argv) { if(*argv == NULL) return 0; if(!strcmp(*argv,"in")) { maxoctets_dir = PPP_OCTETS_DIRECTION_IN; } else if (!strcmp(*argv,"out")) { maxoctets_dir = PPP_OCTETS_DIRECTION_OUT; } else if (!strcmp(*argv,"max")) { maxoctets_dir = PPP_OCTETS_DIRECTION_MAXOVERAL; } else { maxoctets_dir = PPP_OCTETS_DIRECTION_SUM; } return 1; } #ifdef PPP_WITH_PLUGINS static int loadplugin(char **argv) { char *arg = *argv; void *handle; const char *err; void (*init)(void); char *path = arg; const char *vers; if (strchr(arg, '/') == 0) { const char *base = PPP_PATH_PLUGIN; int l = strlen(base) + strlen(arg) + 2; path = malloc(l); if (path == 0) novm("plugin file path"); strlcpy(path, base, l); strlcat(path, "/", l); strlcat(path, arg, l); } handle = dlopen(path, RTLD_GLOBAL | RTLD_NOW); if (handle == 0) { err = dlerror(); if (err != 0) ppp_option_error("%s", err); ppp_option_error("Couldn't load plugin %s", arg); goto err; } init = (void (*)(void))dlsym(handle, "plugin_init"); if (init == 0) { ppp_option_error("%s has no initialization entry point", arg); goto errclose; } vers = (const char *) dlsym(handle, "pppd_version"); if (vers == 0) { warn("Warning: plugin %s has no version information", arg); } else if (strcmp(vers, VERSION) != 0) { ppp_option_error("Plugin %s is for pppd version %s, this is %s", arg, vers, VERSION); goto errclose; } info("Plugin %s loaded.", arg); (*init)(); if (path != arg) free(path); return 1; errclose: dlclose(handle); err: if (path != arg) free(path); return 0; } #endif /* PPP_WITH_PLUGINS */ /* * Set an environment variable specified by the user. */ static int user_setenv(char **argv) { char *arg = argv[0]; char *eqp; struct userenv *uep, **insp; if ((eqp = strchr(arg, '=')) == NULL) { ppp_option_error("missing = in name=value: %s", arg); return 0; } if (eqp == arg) { ppp_option_error("missing variable name: %s", arg); return 0; } for (uep = userenv_list; uep != NULL; uep = uep->ue_next) { int nlen = strlen(uep->ue_name); if (nlen == (eqp - arg) && strncmp(arg, uep->ue_name, nlen) == 0) break; } /* Ignore attempts by unprivileged users to override privileged sources */ if (uep != NULL && !privileged_option && uep->ue_priv) return 1; /* The name never changes, so allocate it with the structure */ if (uep == NULL) { uep = malloc(sizeof (*uep) + (eqp-arg)); strncpy(uep->ue_name, arg, eqp-arg); uep->ue_name[eqp-arg] = '\0'; uep->ue_next = NULL; insp = &userenv_list; while (*insp != NULL) insp = &(*insp)->ue_next; *insp = uep; } else { struct userenv *uep2; for (uep2 = userenv_list; uep2 != NULL; uep2 = uep2->ue_next) { if (uep2 != uep && !uep2->ue_isset) break; } if (uep2 == NULL && !uep->ue_isset) find_option("unset")->flags |= OPT_NOPRINT; free(uep->ue_value); } uep->ue_isset = 1; uep->ue_priv = privileged_option; uep->ue_source = option_source; uep->ue_value = strdup(eqp + 1); curopt->flags &= ~OPT_NOPRINT; return 1; } static void user_setprint(struct option *opt, printer_func printer, void *arg) { struct userenv *uep, *uepnext; uepnext = userenv_list; while (uepnext != NULL && !uepnext->ue_isset) uepnext = uepnext->ue_next; while ((uep = uepnext) != NULL) { uepnext = uep->ue_next; while (uepnext != NULL && !uepnext->ue_isset) uepnext = uepnext->ue_next; (*printer)(arg, "%s=%s", uep->ue_name, uep->ue_value); if (uepnext != NULL) (*printer)(arg, "\t\t# (from %s)\n%s ", uep->ue_source, opt->name); else opt->source = uep->ue_source; } } static int user_unsetenv(char **argv) { struct userenv *uep, **insp; char *arg = argv[0]; if (strchr(arg, '=') != NULL) { ppp_option_error("unexpected = in name: %s", arg); return 0; } if (*arg == '\0') { ppp_option_error("missing variable name for unset"); return 0; } for (uep = userenv_list; uep != NULL; uep = uep->ue_next) { if (strcmp(arg, uep->ue_name) == 0) break; } /* Ignore attempts by unprivileged users to override privileged sources */ if (uep != NULL && !privileged_option && uep->ue_priv) return 1; /* The name never changes, so allocate it with the structure */ if (uep == NULL) { uep = malloc(sizeof (*uep) + strlen(arg)); strcpy(uep->ue_name, arg); uep->ue_next = NULL; insp = &userenv_list; while (*insp != NULL) insp = &(*insp)->ue_next; *insp = uep; } else { struct userenv *uep2; for (uep2 = userenv_list; uep2 != NULL; uep2 = uep2->ue_next) { if (uep2 != uep && uep2->ue_isset) break; } if (uep2 == NULL && uep->ue_isset) find_option("set")->flags |= OPT_NOPRINT; free(uep->ue_value); } uep->ue_isset = 0; uep->ue_priv = privileged_option; uep->ue_source = option_source; uep->ue_value = NULL; curopt->flags &= ~OPT_NOPRINT; return 1; } static void user_unsetprint(struct option *opt, printer_func printer, void *arg) { struct userenv *uep, *uepnext; uepnext = userenv_list; while (uepnext != NULL && uepnext->ue_isset) uepnext = uepnext->ue_next; while ((uep = uepnext) != NULL) { uepnext = uep->ue_next; while (uepnext != NULL && uepnext->ue_isset) uepnext = uepnext->ue_next; (*printer)(arg, "%s", uep->ue_name); if (uepnext != NULL) (*printer)(arg, "\t\t# (from %s)\n%s ", uep->ue_source, opt->name); else opt->source = uep->ue_source; } }