Move applets/applet.c into libbb, allows to get rid of --whole-archive
authorvda <vda@69ca8d6d-28ef-0310-b511-8ec308f3f277>
Wed, 10 Oct 2007 14:41:07 +0000 (14:41 +0000)
committervda <vda@69ca8d6d-28ef-0310-b511-8ec308f3f277>
Wed, 10 Oct 2007 14:41:07 +0000 (14:41 +0000)
(smaller code). Tested in static and shared mode.

git-svn-id: svn://busybox.net/trunk/busybox@20215 69ca8d6d-28ef-0310-b511-8ec308f3f277

applets/applets.c
include/busybox.h
libbb/appletlib.c
scripts/trylink

index 3b4f395..bbf150c 100644 (file)
@@ -1,21 +1,15 @@
 /* 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 Denis Vlasenko
  *
- * 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
 #error Aborting compilation.
 #endif
 
-
-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)
-{
-       USE_FEATURE_SUID(ruid = getuid();)
-}
-#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_appletstruct_and_exit(const struct bb_applet *applet, char **argv)
-{
-       int argc = 1;
-
-       while (argv[argc])
-               argc++;
-
-       /* Reinit some shared global data */
-       optind = 1;
-       xfunc_error_retval = EXIT_FAILURE;
-
-       applet_name = applet->name;
-       if (argc == 2 && !strcmp(argv[1], "--help"))
-               bb_show_usage();
-       if (ENABLE_FEATURE_SUID)
-               check_suid(applet);
-       exit(applet->main(argc, argv));
-}
-
-void run_applet_and_exit(const char *name, char **argv)
-{
-       const struct bb_applet *applet = find_applet_by_name(name);
-       if (applet)
-               run_appletstruct_and_exit(applet, argv);
-       if (!strncmp(name, "busybox", 7))
-               exit(busybox_main(argv));
-}
-
-
+#if ENABLE_BUILD_LIBBUSYBOX
 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");
+       return libbusybox_main(argc, argv);
 }
+#endif
index 1ab51cf..1c23b9b 100644 (file)
@@ -52,5 +52,8 @@ struct bb_applet {
 extern const struct bb_applet applets[];
 extern const unsigned short NUM_APPLETS;
 void bbox_prepare_main(char **argv);
+#if ENABLE_BUILD_LIBBUSYBOX
+int libbusybox_main(int argc, char **argv);
+#endif
 
 #endif /* _BB_INTERNAL_H_ */
index cfa60a9..7808df5 100644 (file)
@@ -1,11 +1,15 @@
 /* vi: set sw=4 ts=4: */
 /*
- * Support for main() which needs to end up in libbusybox, not busybox,
- * if one builds libbusybox.
+ * Utility routines.
  *
- * Copyright (C) 2007 Denys Vlasenko <vda.linux@googlemail.com>
+ * 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.
  *
- * Licensed under GPLv2, see file License in this tarball for details.
+ * 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.
  */
 
 #include <assert.h>
@@ -140,3 +144,544 @@ void bbox_prepare_main(char **argv)
                bb_show_usage();
 #endif
 }
+
+/* The code below can well be in applets/applets.c, as it is used only
+ * for busybox binary, not "individual" binaries.
+ * However, keeping it here and linking it into libbusybox.so
+ * (together with remaining tiny applets/applets.o)
+ * makes it possible to avoid --whole-archive at link time.
+ * This makes (shared busybox) + libbusybox smaller.
+ * (--gc-sections would be even better....)
+ */
+
+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)
+{
+       USE_FEATURE_SUID(ruid = getuid();)
+}
+#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_appletstruct_and_exit(const struct bb_applet *applet, char **argv)
+{
+       int argc = 1;
+
+       while (argv[argc])
+               argc++;
+
+       /* Reinit some shared global data */
+       optind = 1;
+       xfunc_error_retval = EXIT_FAILURE;
+
+       applet_name = applet->name;
+       if (argc == 2 && !strcmp(argv[1], "--help"))
+               bb_show_usage();
+       if (ENABLE_FEATURE_SUID)
+               check_suid(applet);
+       exit(applet->main(argc, argv));
+}
+
+void run_applet_and_exit(const char *name, char **argv)
+{
+       const struct bb_applet *applet = find_applet_by_name(name);
+       if (applet)
+               run_appletstruct_and_exit(applet, argv);
+       if (!strncmp(name, "busybox", 7))
+               exit(busybox_main(argv));
+}
+
+
+#if ENABLE_BUILD_LIBBUSYBOX
+int libbusybox_main(int argc, char **argv)
+#else
+int main(int argc, char **argv)
+#endif
+{
+       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");
+}
index fc87df0..6292dc6 100755 (executable)
@@ -19,18 +19,16 @@ debug=false
 # List of files to link:
 # $l_list                       == --start-group -llib1 -llib2 --end-group
 # --start-group $O_FILES $A_FILES --end-group
-# or for shlib:
-# --start-group --whole-archive $A_FILES --no-whole-archive --end-group
-# otherwise we don't pull in all parts of *.a files. Now we pull in too much.
-# FIXME: make it work without --whole-archive, or better, with --gc-sections.
 #
 # Shared library link:
 # -shared                       self-explanatory
 # -fPIC                         position-independent code
-# -Wl,--enable-new-dtags        ?
-# -Wl,-z,combreloc              ?
-# -Wl,-soname="libbusybox.so.$BB_VER"
-# -static                      Not used, but may be useful! manpage:
+# --enable-new-dtags            ?
+# -z,combreloc                  ?
+# -soname="libbusybox.so.$BB_VER"
+# --undefined=libbusybox_main   Seed name to start pulling from
+#                               (otherwise we'll need --whole-archive)
+# -static                       Not used, but may be useful! manpage:
 #                               "... This option can be used with -shared.
 #                               Doing so means that a shared library
 #                               is being created but that all of the library's
@@ -174,9 +172,10 @@ if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
            -Wl,--enable-new-dtags \
            -Wl,-z,combreloc \
            -Wl,-soname="libbusybox.so.$BB_VER" \
+           -Wl,--undefined=libbusybox_main \
            -Wl,--sort-common \
            -Wl,--sort-section -Wl,alignment \
-           -Wl,--start-group -Wl,--whole-archive $A_FILES -Wl,--no-whole-archive -Wl,--end-group \
+           -Wl,--start-group $A_FILES -Wl,--end-group \
            $l_list \
            -Wl,--warn-common \
            -Wl,-Map -Wl,$EXE.map \