/* vi: set sw=4 ts=4: */
/*
- * Utility routines.
+ * Stub for linking busybox binary against libbusybox.
*
- * Copyright (C) tons of folks. Tracking down who wrote what
- * isn't something I'm going to worry about... If you wrote something
- * here, please feel free to acknowledge your work.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program 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
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
- * Permission has been granted to redistribute this code under the GPL.
+ * Copyright (C) 2007 Denys Vlasenko <vda.linux@googlemail.com>
*
+ * Licensed under GPLv2, see file LICENSE in this source tree.
*/
-
-#include <unistd.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <assert.h>
#include "busybox.h"
-const char usage_messages[] =
-
-#define MAKE_USAGE
-#include "usage.h"
-
-#include "applets.h"
-
-;
-
-#undef MAKE_USAGE
-#undef APPLET
-#undef APPLET_NOUSAGE
-#undef PROTOTYPES
-#include "applets.h"
-
-
-static struct BB_applet *applet_using;
-
-/* The -1 arises because of the {0,NULL,0,-1} entry above. */
-const size_t NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1);
-
-
-#ifdef CONFIG_FEATURE_SUID
-
-static void check_suid (struct BB_applet *app);
-
-#ifdef CONFIG_FEATURE_SUID_CONFIG
-
-#include <sys/stat.h>
-#include <ctype.h>
-#include "pwd_.h"
-#include "grp_.h"
-
-static void parse_config_file (void);
-
-#define CONFIG_FILE "/etc/busybox.conf"
-
-/* applets [] is const, so we have to define this "override" structure */
-struct BB_suid_config
-{
- struct BB_applet *m_applet;
-
- uid_t m_uid;
- gid_t m_gid;
- mode_t m_mode;
-
- struct BB_suid_config *m_next;
-};
-
-static struct BB_suid_config *suid_config;
-static int suid_cfg_readable;
-
-#endif /* CONFIG_FEATURE_SUID_CONFIG */
-
-#endif /* CONFIG_FEATURE_SUID */
-
-
-
-extern void bb_show_usage (void)
+#if ENABLE_BUILD_LIBBUSYBOX
+int main(int argc UNUSED_PARAM, char **argv)
{
- const char *format_string;
- const char *usage_string = usage_messages;
- int i;
-
- for (i = applet_using - applets; i > 0;) {
- if (!*usage_string++) {
- --i;
- }
- }
-
- format_string = "%s\n\nUsage: %s %s\n\n";
- if (*usage_string == '\b')
- format_string = "%s\n\nNo help available.\n\n";
- fprintf (stderr, format_string, bb_msg_full_version, applet_using->name,
- usage_string);
-
- exit (EXIT_FAILURE);
-}
-
-static int applet_name_compare (const void *x, const void *y)
-{
- const char *name = x;
- const struct BB_applet *applet = y;
-
- return strcmp (name, applet->name);
-}
-
-extern const size_t NUM_APPLETS;
-
-struct BB_applet *find_applet_by_name (const char *name)
-{
- return bsearch (name, applets, NUM_APPLETS, sizeof (struct BB_applet),
- applet_name_compare);
-}
-
-void run_applet_by_name (const char *name, int argc, char **argv)
-{
- if(ENABLE_FEATURE_SUID_CONFIG) parse_config_file ();
-
- if(!strncmp(name, "busybox", 7)) busybox_main(argc, argv);
- /* Do a binary search to find the applet entry given the name. */
- applet_using = find_applet_by_name(name);
- if(applet_using) {
- bb_applet_name = applet_using->name;
- if(argc==2 && !strcmp(argv[1], "--help")) bb_show_usage ();
- if(ENABLE_FEATURE_SUID) check_suid (applet_using);
- exit ((*(applet_using->main)) (argc, argv));
- }
+ return lbb_main(argv);
}
-
-
-#ifdef CONFIG_FEATURE_SUID
-
-#ifdef CONFIG_FEATURE_SUID_CONFIG
-
-/* check if u is member of group g */
-static int
-ingroup (uid_t u, gid_t g)
-{
- struct group *grp = getgrgid (g);
-
- if (grp) {
- char **mem;
-
- for (mem = grp->gr_mem; *mem; mem++) {
- struct passwd *pwd = getpwnam (*mem);
-
- if (pwd && (pwd->pw_uid == u))
- return 1;
- }
- }
- return 0;
-}
-
#endif
-
-
-void
-check_suid (struct BB_applet *applet)
-{
- uid_t ruid = getuid (); /* real [ug]id */
- uid_t rgid = getgid ();
-
-#ifdef CONFIG_FEATURE_SUID_CONFIG
- if (suid_cfg_readable) {
- struct BB_suid_config *sct;
-
- for (sct = suid_config; sct; sct = sct->m_next) {
- if (sct->m_applet == applet)
- break;
- }
- if (sct) {
- mode_t m = sct->m_mode;
-
- if (sct->m_uid == ruid) /* same uid */
- m >>= 6;
- else if ((sct->m_gid == rgid) || ingroup (ruid, sct->m_gid)) /* same group / in group */
- m >>= 3;
-
- if (!(m & S_IXOTH)) /* is x bit not set ? */
- bb_error_msg_and_die ("You have no permission to run this applet!");
-
- if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { /* *both* have to be set for sgid */
- if (setegid (sct->m_gid))
- bb_error_msg_and_die
- ("BusyBox binary has insufficient rights to set proper GID for applet!");
- } else
- setgid (rgid); /* no sgid -> drop */
-
- if (sct->m_mode & S_ISUID) {
- if (seteuid (sct->m_uid))
- bb_error_msg_and_die
- ("BusyBox binary has insufficient rights to set proper UID for applet!");
- } else
- setuid (ruid); /* no suid -> drop */
- } else {
- /* default: drop all priviledges */
- setgid (rgid);
- setuid (ruid);
- }
- return;
- } else {
-#ifndef CONFIG_FEATURE_SUID_CONFIG_QUIET
- static int onetime = 0;
-
- if (!onetime) {
- onetime = 1;
- fprintf (stderr, "Using fallback suid method\n");
- }
-#endif
- }
-#endif
-
- if (applet->need_suid == _BB_SUID_ALWAYS) {
- if (geteuid () != 0)
- bb_error_msg_and_die ("This applet requires root priviledges!");
- } else if (applet->need_suid == _BB_SUID_NEVER) {
- setgid (rgid); /* drop all priviledges */
- setuid (ruid);
- }
-}
-
-#ifdef CONFIG_FEATURE_SUID_CONFIG
-
-/* This should probably be a libbb routine. In that case,
- * I'd probably rename it to something like bb_trimmed_slice.
- */
-static char *get_trimmed_slice(char *s, char *e)
-{
- /* First, consider the value at e to be nul and back up until we
- * reach a non-space char. Set the char after that (possibly at
- * the original e) to nul. */
- while (e-- > s) {
- if (!isspace(*e)) {
- break;
- }
- }
- e[1] = 0;
-
- /* Next, advance past all leading space and return a ptr to the
- * first non-space char; possibly the terminating nul. */
- return (char *) bb_skip_whitespace(s);
-}
-
-
-#define parse_error(x) { err=x; goto pe_label; }
-
-/* Don't depend on the tools to combine strings. */
-static const char config_file[] = CONFIG_FILE;
-
-/* There are 4 chars + 1 nul for each of user/group/other. */
-static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
-
-/* We don't supply a value for the nul, so an index adjustment is
- * necessary below. Also, we use unsigned short here to save some
- * space even though these are really mode_t values. */
-static const unsigned short mode_mask[] = {
- /* SST sst xxx --- */
- S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
- S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
- 0, S_IXOTH, S_IXOTH, 0 /* other */
-};
-
-static void parse_config_file(void)
-{
- struct BB_suid_config *sct_head;
- struct BB_suid_config *sct;
- struct BB_applet *applet;
- FILE *f;
- char *err;
- char *s;
- char *e;
- int i, lc, section;
- char buffer[256];
- struct stat st;
-
- assert(!suid_config); /* Should be set to NULL by bss init. */
-
- if ((stat(config_file, &st) != 0) /* No config file? */
- || !S_ISREG(st.st_mode) /* Not a regular file? */
- || (st.st_uid != 0) /* Not owned by root? */
- || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
- || !(f = fopen(config_file, "r")) /* Can not open? */
- ) {
- return;
- }
-
- suid_cfg_readable = 1;
- sct_head = NULL;
- section = lc = 0;
-
- do {
- s = buffer;
-
- if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
- if (ferror(f)) { /* Make sure it wasn't a read error. */
- parse_error("reading");
- }
- fclose(f);
- suid_config = sct_head; /* Success, so set the pointer. */
- return;
- }
-
- lc++; /* Got a (partial) line. */
-
- /* If a line is too long for our buffer, we consider it an error.
- * The following test does mistreat one corner case though.
- * If the final line of the file does not end with a newline and
- * yet exactly fills the buffer, it will be treated as too long
- * even though there isn't really a problem. But it isn't really
- * worth adding code to deal with such an unlikely situation, and
- * we do err on the side of caution. Besides, the line would be
- * too long if it did end with a newline. */
- if (!strchr(s, '\n') && !feof(f)) {
- parse_error("line too long");
- }
-
- /* Trim leading and trailing whitespace, ignoring comments, and
- * check if the resulting string is empty. */
- if (!*(s = get_trimmed_slice(s, strchrnul(s, '#')))) {
- continue;
- }
-
- /* Check for a section header. */
-
- if (*s == '[') {
- /* Unlike the old code, we ignore leading and trailing
- * whitespace for the section name. We also require that
- * there are no stray characters after the closing bracket. */
- if (!(e = strchr(s, ']')) /* Missing right bracket? */
- || e[1] /* Trailing characters? */
- || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
- ) {
- parse_error("section header");
- }
- /* Right now we only have one section so just check it.
- * If more sections are added in the future, please don't
- * resort to cascading ifs with multiple strcasecmp calls.
- * That kind of bloated code is all too common. A loop
- * and a string table would be a better choice unless the
- * number of sections is very small. */
- if (strcasecmp(s, "SUID") == 0) {
- section = 1;
- continue;
- }
- section = -1; /* Unknown section so set to skip. */
- continue;
- }
-
- /* Process sections. */
-
- if (section == 1) { /* SUID */
- /* Since we trimmed leading and trailing space above, we're
- * now looking for strings of the form
- * <key>[::space::]*=[::space::]*<value>
- * where both key and value could contain inner whitespace. */
-
- /* First get the key (an applet name in our case). */
- if (!!(e = strchr(s, '='))) {
- s = get_trimmed_slice(s, e);
- }
- if (!e || !*s) { /* Missing '=' or empty key. */
- parse_error("keyword");
- }
-
- /* Ok, we have an applet name. Process the rhs if this
- * applet is currently built in and ignore it otherwise.
- * Note: This can hide config file bugs which only pop
- * up when the busybox configuration is changed. */
- if ((applet = find_applet_by_name(s))) {
- /* Note: We currently don't check for duplicates!
- * The last config line for each applet will be the
- * one used since we insert at the head of the list.
- * I suppose this could be considered a feature. */
- sct = xmalloc(sizeof(struct BB_suid_config));
- sct->m_applet = applet;
- sct->m_mode = 0;
- sct->m_next = sct_head;
- sct_head = sct;
-
- /* Get the specified mode. */
-
- e = (char *) bb_skip_whitespace(e+1);
-
- for (i=0 ; i < 3 ; i++) {
- const char *q;
- if (!*(q = strchrnul(mode_chars + 5*i, *e++))) {
- parse_error("mode");
- }
- /* Adjust by -i to account for nul. */
- sct->m_mode |= mode_mask[(q - mode_chars) - i];
- }
-
- /* Now get the the user/group info. */
-
- s = (char *) bb_skip_whitespace(e);
-
- /* Note: We require whitespace between the mode and the
- * user/group info. */
- if ((s == e) || !(e = strchr(s, '.'))) {
- parse_error("<uid>.<gid>");
- }
- *e++ = 0;
-
- /* We can't use get_ug_id here since it would exit()
- * if a uid or gid was not found. Oh well... */
- {
- char *e2;
-
- sct->m_uid = strtoul(s, &e2, 10);
- if (*e2 || (s == e2)) {
- struct passwd *pwd;
- if (!(pwd = getpwnam(s))) {
- parse_error("user");
- }
- sct->m_uid = pwd->pw_uid;
- }
-
- sct->m_gid = strtoul(e, &e2, 10);
- if (*e2 || (e == e2)) {
- struct group *grp;
- if (!(grp = getgrnam(e))) {
- parse_error("group");
- }
- sct->m_gid = grp->gr_gid;
- }
- }
- }
- continue;
- }
-
- /* Unknown sections are ignored. */
-
- /* Encountering configuration lines prior to seeing a
- * section header is treated as an error. This is how
- * the old code worked, but it may not be desirable.
- * We may want to simply ignore such lines in case they
- * are used in some future version of busybox. */
- if (!section) {
- parse_error("keyword outside section");
- }
-
- } while (1);
-
- pe_label:
- fprintf(stderr, "Parse error in %s, line %d: %s\n",
- config_file, lc, err);
-
- fclose(f);
- /* Release any allocated memory before returning. */
- while (sct_head) {
- sct = sct_head->m_next;
- free(sct_head);
- sct_head = sct;
- }
- return;
-}
-
-#endif
-
-#endif
-
-/* END CODE */
-/*
- Local Variables:
- c-file-style: "linux"
- c-basic-offset: 4
- tab-width: 4
-End:
-*/