/* 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.
+ * Copyright (C) 2007 Denys Vlasenko <vda.linux@googlemail.com>
*
- * 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.
- *
- * Licensed under GPLv2 or later, see file License in this tarball for details.
+ * Licensed under GPLv2, see file License in this tarball for details.
*/
#include <assert.h>
#include "busybox.h"
-
-/* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
-#if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__)
-#warning Static linking against glibc produces buggy executables
-#warning (glibc does not cope well with ld --gc-sections).
-#warning See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
-#warning Note that glibc is unsuitable for static linking anyway.
-#warning If you still want to do it, remove -Wl,--gc-sections
-#warning from top-level Makefile and remove this warning.
-#error Aborting compilation.
-#endif
-
-
-const struct bb_applet *current_applet;
-const char *applet_name;
-#if !BB_MMU
-bool re_execed;
-#endif
-
-USE_FEATURE_SUID(static uid_t ruid;) /* real uid */
-
-#if ENABLE_FEATURE_SUID_CONFIG
-
-/* applets[] is const, so we have to define this "override" structure */
-static struct BB_suid_config {
- const struct bb_applet *m_applet;
- uid_t m_uid;
- gid_t m_gid;
- mode_t m_mode;
- struct BB_suid_config *m_next;
-} *suid_config;
-
-static bool suid_cfg_readable;
-
-/* 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;
-}
-
-/* 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 skip_whitespace(s);
-}
-
-/* Don't depend on the tools to combine strings. */
-static const char config_file[] ALIGN1 = "/etc/busybox.conf";
-
-/* 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[] ALIGN2 = {
- /* 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 */
-};
-
-#define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
-
-static void parse_config_file(void)
-{
- struct BB_suid_config *sct_head;
- struct BB_suid_config *sct;
- const struct bb_applet *applet;
- FILE *f;
- const char *errmsg;
- char *s;
- char *e;
- int i;
- unsigned lc;
- smallint section;
- char buffer[256];
- struct stat st;
-
- assert(!suid_config); /* Should be set to NULL by bss init. */
-
- ruid = getuid();
- if (ruid == 0) /* run by root - don't need to even read config file */
- return;
-
- 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")) /* Cannot open? */
- ) {
- return;
- }
-
- suid_cfg_readable = 1;
- sct_head = NULL;
- section = lc = 0;
-
- while (1) {
- 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. */
- s = get_trimmed_slice(s, strchrnul(s, '#'));
- if (!*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. */
- e = strchr(s, ']');
- if (!e /* 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). */
- e = strchr(s, '=');
- if (e) {
- 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. */
- applet = find_applet_by_name(s);
- if (applet) {
- /* 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 = skip_whitespace(e+1);
-
- for (i = 0; i < 3; i++) {
- /* There are 4 chars + 1 nul for each of user/group/other. */
- static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
-
- const char *q;
- q = strchrnul(mode_chars + 5*i, *e++);
- if (!*q) {
- 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 = 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... */
- sct->m_uid = bb_strtoul(s, NULL, 10);
- if (errno) {
- struct passwd *pwd = getpwnam(s);
- if (!pwd) {
- parse_error("user");
- }
- sct->m_uid = pwd->pw_uid;
- }
-
- sct->m_gid = bb_strtoul(e, NULL, 10);
- if (errno) {
- struct group *grp;
- grp = getgrnam(e);
- if (!grp) {
- 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, errmsg);
-
- fclose(f);
- /* Release any allocated memory before returning. */
- while (sct_head) {
- sct = sct_head->m_next;
- free(sct_head);
- sct_head = sct;
- }
-}
-#else
-static inline void parse_config_file(void)
+#if ENABLE_BUILD_LIBBUSYBOX
+int main(int argc UNUSED_PARAM, char **argv)
{
- USE_FEATURE_SUID(ruid = getuid();)
+ return lbb_main(argv);
}
-#endif /* FEATURE_SUID_CONFIG */
-
-
-#if ENABLE_FEATURE_SUID
-static void check_suid(const struct bb_applet *applet)
-{
- gid_t rgid; /* real gid */
-
- if (ruid == 0) /* set by parse_config_file() */
- return; /* run by root - no need to check more */
- rgid = getgid();
-
-#if ENABLE_FEATURE_SUID_CONFIG
- if (suid_cfg_readable) {
- uid_t uid;
- struct BB_suid_config *sct;
- mode_t m;
-
- for (sct = suid_config; sct; sct = sct->m_next) {
- if (sct->m_applet == applet)
- goto found;
- }
- /* default: drop all privileges */
- xsetgid(rgid);
- xsetuid(ruid);
- return;
- found:
- 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!");
-
- /* _both_ sgid and group_exec have to be set for setegid */
- if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
- rgid = sct->m_gid;
- /* else (no setegid) we will set egid = rgid */
-
- /* We set effective AND saved ids. If saved-id is not set
- * like we do below, seteiud(0) can still later succeed! */
- if (setresgid(-1, rgid, rgid))
- bb_perror_msg_and_die("setresgid");
-
- /* do we have to set effective uid? */
- uid = ruid;
- if (sct->m_mode & S_ISUID)
- uid = sct->m_uid;
- /* else (no seteuid) we will set euid = ruid */
-
- if (setresuid(-1, uid, uid))
- bb_perror_msg_and_die("setresuid");
- return;
- }
-#if !ENABLE_FEATURE_SUID_CONFIG_QUIET
- {
- static bool onetime = 0;
-
- if (!onetime) {
- onetime = 1;
- fprintf(stderr, "Using fallback suid method\n");
- }
- }
#endif
-#endif
-
- if (applet->need_suid == _BB_SUID_ALWAYS) {
- /* Real uid is not 0. If euid isn't 0 too, suid bit
- * is most probably not set on our executable */
- if (geteuid())
- bb_error_msg_and_die("applet requires root privileges!");
- } else if (applet->need_suid == _BB_SUID_NEVER) {
- xsetgid(rgid); /* drop all privileges */
- xsetuid(ruid);
- }
-}
-#else
-#define check_suid(x) ((void)0)
-#endif /* FEATURE_SUID */
-
-
-#if ENABLE_FEATURE_INSTALLER
-/* create (sym)links for each applet */
-static void install_links(const char *busybox, int use_symbolic_links)
-{
- /* directory table
- * this should be consistent w/ the enum,
- * busybox.h::bb_install_loc_t, or else... */
- static const char usr_bin [] ALIGN1 = "/usr/bin";
- static const char usr_sbin[] ALIGN1 = "/usr/sbin";
- static const char *const install_dir[] = {
- &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
- &usr_bin [4], /* "/bin" */
- &usr_sbin[4], /* "/sbin" */
- usr_bin,
- usr_sbin
- };
-
- int (*lf)(const char *, const char *) = link;
- char *fpc;
- int i;
- int rc;
-
- if (use_symbolic_links)
- lf = symlink;
-
- for (i = 0; applets[i].name != NULL; i++) {
- fpc = concat_path_file(
- install_dir[applets[i].install_loc],
- applets[i].name);
- rc = lf(busybox, fpc);
- if (rc != 0 && errno != EEXIST) {
- bb_simple_perror_msg(fpc);
- }
- free(fpc);
- }
-}
-#else
-#define install_links(x,y) ((void)0)
-#endif /* FEATURE_INSTALLER */
-
-
-/* If we were called as "busybox..." */
-static int busybox_main(char **argv)
-{
- if (!argv[1]) {
- /* Called without arguments */
- const struct bb_applet *a;
- int col, output_width;
- help:
- output_width = 80;
- if (ENABLE_FEATURE_AUTOWIDTH) {
- /* Obtain the terminal width */
- get_terminal_width_height(0, &output_width, NULL);
- }
- /* leading tab and room to wrap */
- output_width -= sizeof("start-stop-daemon, ") + 8;
-
- printf("%s multi-call binary\n", bb_banner); /* reuse const string... */
- printf("Copyright (C) 1998-2006 Erik Andersen, Rob Landley, and others.\n"
- "Licensed under GPLv2. See source distribution for full notice.\n"
- "\n"
- "Usage: busybox [function] [arguments]...\n"
- " or: [function] [arguments]...\n"
- "\n"
- "\tBusyBox is a multi-call binary that combines many common Unix\n"
- "\tutilities into a single executable. Most people will create a\n"
- "\tlink to busybox for each function they wish to use and BusyBox\n"
- "\twill act like whatever it was invoked as!\n"
- "\nCurrently defined functions:\n");
- col = 0;
- a = applets;
- while (a->name) {
- if (col > output_width) {
- puts(",");
- col = 0;
- }
- col += printf("%s%s", (col ? ", " : "\t"), a->name);
- a++;
- }
- puts("\n");
- return 0;
- }
-
- if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
- const char *busybox;
- busybox = xmalloc_readlink(bb_busybox_exec_path);
- if (!busybox)
- busybox = bb_busybox_exec_path;
- /* -s makes symlinks */
- install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0);
- return 0;
- }
-
- if (strcmp(argv[1], "--help") == 0) {
- /* "busybox --help [<applet>]" */
- if (!argv[2])
- goto help;
- /* convert to "<applet> --help" */
- argv[0] = argv[2];
- argv[2] = NULL;
- } else {
- /* "busybox <applet> arg1 arg2 ..." */
- argv++;
- }
- /* We support "busybox /a/path/to/applet args..." too. Allows for
- * "#!/bin/busybox"-style wrappers */
- applet_name = bb_get_last_path_component_nostrip(argv[0]);
- run_applet_and_exit(applet_name, argv);
- bb_error_msg_and_die("applet not found");
-}
-
-void run_current_applet_and_exit(char **argv)
-{
- int argc = 1;
-
- while (argv[argc])
- argc++;
-
- /* Reinit some shared global data */
- optind = 1;
- xfunc_error_retval = EXIT_FAILURE;
-
- applet_name = current_applet->name;
- if (argc == 2 && !strcmp(argv[1], "--help"))
- bb_show_usage();
- if (ENABLE_FEATURE_SUID)
- check_suid(current_applet);
- exit(current_applet->main(argc, argv));
-}
-
-void run_applet_and_exit(const char *name, char **argv)
-{
- current_applet = find_applet_by_name(name);
- if (current_applet)
- run_current_applet_and_exit(argv);
- if (!strncmp(name, "busybox", 7))
- exit(busybox_main(argv));
-}
-
-
-int main(int argc, char **argv)
-{
- bbox_prepare_main(argv);
-
-#if !BB_MMU
- /* NOMMU re-exec trick sets high-order bit in first byte of name */
- if (argv[0][0] & 0x80) {
- re_execed = 1;
- argv[0][0] &= 0x7f;
- }
-#endif
- applet_name = argv[0];
- if (applet_name[0] == '-')
- applet_name++;
- applet_name = bb_basename(applet_name);
-
- parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
-
- run_applet_and_exit(applet_name, argv);
- bb_error_msg_and_die("applet not found");
-}
projects / oweals / busybox.git / blobdiff