Mercurial > hg > toybox
view main.c @ 1512:7afd32673a5c draft 0.5.0
Workaround for musl's faccessat bug (the rm -r "error: is a directory" thing).
The Linux man page says I can use AT_SYMLINK_NOFOLLOW. It works in glibc,
uclibc, and klibc, but musl returns -EINVAL any time you pass in that flag
and the maintainer says that's not a bug and insists the man page and those
other libraries all change to match musl's behavior.
Toybox uses it to avoid scheduling unnecessary metadata writes for things we're
about to delete (have to chmod unreadable directories so we can descend into
them to delete their contents, the chmod happens before we descend so the
disk I/O has plenty of time to be scheduled) because the extra writes wear out
SSD faster. It's just an optimization and I don't really care if it works
_well_ (the fchmodat call _also_ takes AT_SYMLINK_NOFOLLOW so that's covered),
but musl's behavior uniquely makes the check always error and thus breaks normal
"rm -r".
Yes this workaround is checking #ifdef __MUSL__ which the library does not
supply (because its code is perfect and will thus never need to be worked
around). You can CFLAGS=-D__MUSL__ if you don't echo "#define __MUSL__" >>
include/features.h when installing the library.
author | Rob Landley <rob@landley.net> |
---|---|
date | Thu, 02 Oct 2014 07:24:38 -0500 |
parents | c51a4dbe5db7 |
children | 3c77af6f81cc |
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/* Toybox infrastructure. * * Copyright 2006 Rob Landley <rob@landley.net> */ #include "toys.h" // Populate toy_list[]. #undef NEWTOY #undef OLDTOY #define NEWTOY(name, opts, flags) {#name, name##_main, opts, flags}, #define OLDTOY(name, oldname, opts, flags) {#name, oldname##_main, opts, flags}, struct toy_list toy_list[] = { #include "generated/newtoys.h" }; // global context for this command. struct toy_context toys; union global_union this; char toybuf[4096], libbuf[4096]; struct toy_list *toy_find(char *name) { int top, bottom, middle; if (!CFG_TOYBOX) return 0; // If the name starts with "toybox" accept that as a match. Otherwise // skip the first entry, which is out of order. if (!strncmp(name,"toybox",6)) return toy_list; bottom = 1; // Binary search to find this command. top = ARRAY_LEN(toy_list)-1; for (;;) { int result; middle = (top+bottom)/2; if (middle<bottom || middle>top) return NULL; result = strcmp(name,toy_list[middle].name); if (!result) return toy_list+middle; if (result<0) top=--middle; else bottom = ++middle; } } // Figure out whether or not anything is using the option parsing logic, // because the compiler can't figure out whether or not to optimize it away // on its' own. NEED_OPTIONS becomes a constant allowing if() to optimize // stuff out via dead code elimination. #undef NEWTOY #undef OLDTOY #define NEWTOY(name, opts, flags) opts || #define OLDTOY(name, oldname, opts, flags) opts || static const int NEED_OPTIONS = #include "generated/newtoys.h" 0; // Ends the opts || opts || opts... // Subset of init needed by singlemain static void toy_singleinit(struct toy_list *which, char *argv[]) { toys.which = which; toys.argv = argv; if (CFG_TOYBOX_I18N) setlocale(LC_ALL, "C"+!!(which->flags & TOYFLAG_LOCALE)); if (CFG_TOYBOX_HELP_DASHDASH && argv[1] && !strcmp(argv[1], "--help")) { if (CFG_TOYBOX && toys.which == toy_list && toys.argv[2]) if (!(toys.which = toy_find(toys.argv[2]))) return; show_help(); xexit(); } if (NEED_OPTIONS && which->options) get_optflags(); else { toys.optargs = argv+1; for (toys.optc=0; toys.optargs[toys.optc]; toys.optc++); } toys.old_umask = umask(0); if (!(which->flags & TOYFLAG_UMASK)) umask(toys.old_umask); toys.signalfd--; toys.toycount = ARRAY_LEN(toy_list); } // Setup toybox global state for this command. void toy_init(struct toy_list *which, char *argv[]) { // Drop permissions for non-suid commands. if (CFG_TOYBOX_SUID) { uid_t uid = getuid(), euid = geteuid(); if (!(which->flags & TOYFLAG_STAYROOT)) { if (uid != euid) { if (!setuid(uid)) perror_exit("setuid %d->%d", euid, uid); // drop root else euid = uid; } } else if (CFG_TOYBOX_DEBUG && uid && which != toy_list) error_msg("Not installed suid root"); if ((which->flags & TOYFLAG_NEEDROOT) && euid) { toys.exithelp++; error_exit("Not root"); } } // Free old toys contents (to be reentrant), but leave rebound if any if (toys.optargs != toys.argv+1) free(toys.optargs); memset(&toys, 0, offsetof(struct toy_context, rebound)); // Subset of init needed by singlemain. toy_singleinit(which, argv); } // Like exec() but runs an internal toybox command instead of another file. // Only returns if it can't run command internally, otherwise exit() when done. void toy_exec(char *argv[]) { struct toy_list *which; // Return if we can't find it, or need to re-exec to acquire root, // or if stack depth is getting silly. if (!(which = toy_find(argv[0]))) return; if (toys.recursion && (which->flags & TOYFLAG_ROOTONLY) && getuid()) return; if (toys.recursion++ > 5) return; // Run command toy_init(which, argv); if (toys.which) toys.which->toy_main(); if (fflush(NULL) || ferror(stdout)) perror_exit("write"); xexit(); } // Multiplexer command, first argument is command to run, rest are args to that. // If first argument starts with - output list of command install paths. void toybox_main(void) { static char *toy_paths[]={"usr/","bin/","sbin/",0}; int i, len = 0; toys.which = toy_list; if (toys.argv[1]) { toys.optc = 0; toy_exec(toys.argv+1); if (toys.argv[1][0] == '-') goto list; error_exit("Unknown command %s",toys.argv[1]); } list: // Output list of command. for (i=1; i<ARRAY_LEN(toy_list); i++) { int fl = toy_list[i].flags; if (fl & TOYMASK_LOCATION) { if (toys.argv[1]) { int j; for (j=0; toy_paths[j]; j++) if (fl & (1<<j)) len += printf("%s", toy_paths[j]); } len += printf("%s ",toy_list[i].name); if (len>65) { xputc('\n'); len=0; } } } xputc('\n'); } int main(int argc, char *argv[]) { if (CFG_TOYBOX) { // Trim path off of command name *argv = basename(*argv); // Call the multiplexer, adjusting this argv[] to be its' argv[1]. // (It will adjust it back before calling toy_exec().) toys.argv = argv-1; toybox_main(); } else { // a single toybox command built standalone with no multiplexer toy_singleinit(toy_list, argv); toy_list->toy_main(); if (fflush(NULL) || ferror(stdout)) perror_exit("write"); } return toys.exitval; }