vapier 14/03/21 05:27:21 Modified: scanelf.c Log: rewrite which() so that it works and does not break $PATH we were walking the $PATH in reverse which it should have been forwards. we were also modifying the pointer we got back from getenv() which meant any time we ran external code, $PATH would be truncated. finally, we never actually checked the first element -- we would bail before we got a chance.
Revision Changes Path 1.264 pax-utils/scanelf.c file : http://sources.gentoo.org/viewvc.cgi/gentoo-projects/pax-utils/scanelf.c?rev=1.264&view=markup plain: http://sources.gentoo.org/viewvc.cgi/gentoo-projects/pax-utils/scanelf.c?rev=1.264&content-type=text/plain diff : http://sources.gentoo.org/viewvc.cgi/gentoo-projects/pax-utils/scanelf.c?r1=1.263&r2=1.264 Index: scanelf.c =================================================================== RCS file: /var/cvsroot/gentoo-projects/pax-utils/scanelf.c,v retrieving revision 1.263 retrieving revision 1.264 diff -u -r1.263 -r1.264 --- scanelf.c 20 Mar 2014 08:08:37 -0000 1.263 +++ scanelf.c 21 Mar 2014 05:27:21 -0000 1.264 @@ -1,13 +1,13 @@ /* * Copyright 2003-2012 Gentoo Foundation * Distributed under the terms of the GNU General Public License v2 - * $Header: /var/cvsroot/gentoo-projects/pax-utils/scanelf.c,v 1.263 2014/03/20 08:08:37 vapier Exp $ + * $Header: /var/cvsroot/gentoo-projects/pax-utils/scanelf.c,v 1.264 2014/03/21 05:27:21 vapier Exp $ * * Copyright 2003-2012 Ned Ludd - <so...@gentoo.org> * Copyright 2004-2012 Mike Frysinger - <vap...@gentoo.org> */ -static const char rcsid[] = "$Id: scanelf.c,v 1.263 2014/03/20 08:08:37 vapier Exp $"; +static const char rcsid[] = "$Id: scanelf.c,v 1.264 2014/03/21 05:27:21 vapier Exp $"; const char argv0[] = "scanelf"; #include "paxinc.h" @@ -70,26 +70,66 @@ static size_t ldcache_size = 0; static unsigned long setpax = 0UL; -static int has_objdump = 0; +static const char *objdump; /* find the path to a file by name */ -static int bin_in_path(const char *fname) +static const char *which(const char *fname, const char *envvar) { - char fullpath[__PAX_UTILS_PATH_MAX]; - char *path, *p; + size_t path_len, fname_len; + const char *env_path; + char *path, *p, *ep; + + p = getenv(envvar); + if (p) + return p; - path = getenv("PATH"); - if (!path) - return 0; + env_path = getenv("PATH"); + if (!env_path) + return NULL; - while ((p = strrchr(path, ':')) != NULL) { - snprintf(fullpath, sizeof(fullpath), "%s/%s", p + 1, fname); - *p = 0; - if (access(fullpath, R_OK) != -1) - return 1; + /* Create a copy of the $PATH that we can safely modify. + * Make it a little bigger so we can append "/fname". + * We do this twice -- once for a perm copy, and once for + * room at the end of the last element. */ + path_len = strlen(env_path); + fname_len = strlen(fname); + path = xmalloc(path_len + (fname_len * 2) + 2 + 2); + memcpy(path, env_path, path_len + 1); + + p = path + path_len + 1 + fname_len + 1; + *p = '/'; + memcpy(p + 1, fname, fname_len + 1); + + /* Repoint fname to the copy in the env string as it has + * the leading slash which we can include in a single memcpy. + * Increase the fname len to include the '/' and '\0'. */ + fname = p; + fname_len += 2; + + p = path; + while (p) { + ep = strchr(p, ':'); + /* Append the /foo path to the current element. */ + if (ep) + memcpy(ep, fname, fname_len); + else + memcpy(path + path_len, fname, fname_len); + + if (access(p, R_OK) != -1) + return p; + + p = ep; + if (ep) { + /* If not the last element, restore the chunk we clobbered. */ + size_t offset = ep - path; + size_t restore = min(path_len - offset, fname_len); + memcpy(ep, env_path + offset, restore); + ++p; + } } - return 0; + free(path); + return NULL; } static FILE *fopenat_r(int dir_fd, const char *path) @@ -570,17 +610,18 @@ } else \ printf("(optimized out)"); \ printf(" [0x%lX]\n", (unsigned long)offset_tmp); \ - if (be_verbose && has_objdump) { \ + if (be_verbose && objdump) { \ Elf ## B ## _Addr end_addr = offset_tmp + EGET(func->st_size); \ char *sysbuf; \ size_t syslen; \ - const char sysfmt[] = "objdump -r -R -d -w -l --start-address=0x%lX --stop-address=0x%lX %s | grep --color -i -C 3 '.*[[:space:]]%lX:[[:space:]]*R_.*'\n"; \ - syslen = sizeof(sysfmt) + strlen(elf->filename) + 3 * sizeof(unsigned long) + 1; \ + const char sysfmt[] = "%s -r -R -d -w -l --start-address=0x%lX --stop-address=0x%lX %s | grep --color -i -C 3 '.*[[:space:]]%lX:[[:space:]]*R_.*'\n"; \ + syslen = sizeof(sysfmt) + strlen(objdump) + strlen(elf->filename) + 3 * sizeof(unsigned long) + 1; \ sysbuf = xmalloc(syslen); \ if (end_addr < r_offset) \ /* not uncommon when things are optimized out */ \ end_addr = r_offset + 0x100; \ snprintf(sysbuf, syslen, sysfmt, \ + objdump, \ (unsigned long)offset_tmp, \ (unsigned long)end_addr, \ elf->filename, \ @@ -2230,7 +2271,7 @@ } } if (show_textrels && be_verbose) - has_objdump = bin_in_path("objdump"); + objdump = which("objdump", "OBJDUMP"); /* precompile all the regexes */ if (g_match) { regex_t preg;
