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-rw-r--r--pseudo_util.c499
1 files changed, 499 insertions, 0 deletions
diff --git a/pseudo_util.c b/pseudo_util.c
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index 0000000..2e21824
--- /dev/null
+++ b/pseudo_util.c
@@ -0,0 +1,499 @@
+/*
+ * pseudo_util.c, miscellaneous utility functions
+ *
+ * Copyright (c) 2008-2010 Wind River Systems, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the Lesser GNU General Public License version 2.1 as
+ * published by the Free Software Foundation.
+ *
+ * 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 Lesser GNU General Public License for more details.
+ *
+ * You should have received a copy of the Lesser GNU General Public License
+ * version 2.1 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include "pseudo.h"
+#include "pseudo_ipc.h"
+#include "pseudo_db.h"
+
+/* 3 = detailed protocol analysis
+ * 2 = higher-level protocol analysis
+ * 1 = stuff that might go wrong
+ * 0 = fire and arterial bleeding
+ */
+static int max_debug_level = 0;
+int pseudo_util_debug_fd = 2;
+static int debugged_newline = 1;
+static char pid_text[32];
+static size_t pid_len;
+static int pseudo_append_element(char **newpath, size_t *allocated, char **current, const char *element, size_t elen, int leave_last);
+static int pseudo_append_elements(char **newpath, size_t *allocated, char **current, const char *elements, size_t elen, int leave_last);
+extern char **environ;
+
+char *pseudo_version = PSEUDO_VERSION;
+
+void
+pseudo_debug_terse(void) {
+ if (max_debug_level > 0)
+ --max_debug_level;
+}
+
+void
+pseudo_debug_verbose(void) {
+ ++max_debug_level;
+}
+
+int
+pseudo_diag(char *fmt, ...) {
+ va_list ap;
+ char debuff[8192];
+ int len;
+ /* gcc on Ubuntu 8.10 requires that you examine the return from
+ * write(), and won't let you cast it to void. Of course, if you
+ * can't print error messages, there's nothing to do.
+ */
+ int wrote = 0;
+
+ va_start(ap, fmt);
+ len = vsnprintf(debuff, 8192, fmt, ap);
+ va_end(ap);
+
+ if (len > 8192)
+ len = 8192;
+
+ if (debugged_newline && max_debug_level > 1) {
+ wrote += write(pseudo_util_debug_fd, pid_text, pid_len);
+ }
+ debugged_newline = (debuff[len - 1] == '\n');
+
+ wrote += write(pseudo_util_debug_fd, "pseudo: ", 8);
+ wrote += write(pseudo_util_debug_fd, debuff, len);
+ return wrote;
+}
+
+int
+pseudo_debug_real(int level, char *fmt, ...) {
+ va_list ap;
+ char debuff[8192];
+ int len;
+ int wrote = 0;
+
+ if (max_debug_level < level)
+ return 0;
+
+ va_start(ap, fmt);
+ len = vsnprintf(debuff, 8192, fmt, ap);
+ va_end(ap);
+
+ if (len > 8192)
+ len = 8192;
+
+ if (debugged_newline && max_debug_level > 1) {
+ wrote += write(pseudo_util_debug_fd, pid_text, pid_len);
+ }
+ debugged_newline = (debuff[len - 1] == '\n');
+
+ wrote += write(pseudo_util_debug_fd, debuff, len);
+ return wrote;
+}
+
+/* given n, pick a multiple of block enough bigger than n
+ * to give us some breathing room.
+ */
+static inline size_t
+round_up(size_t n, size_t block) {
+ return block * (((n + block / 4) / block) + 1);
+}
+
+/* store pid in text form for prepending to messages */
+void
+pseudo_new_pid() {
+ pid_len = snprintf(pid_text, 32, "%d: ", getpid());
+ pseudo_debug(2, "new pid.\n");
+}
+
+/* helper function for pseudo_fix_path
+ * adds "element" to "newpath" at location current, if it can, then
+ * checks whether this now points to a symlink. If it does, expand
+ * the symlink, appending each element in turn the same way.
+ */
+static int
+pseudo_append_element(char **pnewpath, size_t *pallocated, char **pcurrent, const char *element, size_t elen, int leave_this) {
+ static int link_recursion = 0;
+ size_t curlen, allocated;
+ char *newpath, *current;
+ struct stat64 buf;
+ if (!pnewpath || !*pnewpath || !pallocated || !pcurrent || !*pcurrent || !element) {
+ pseudo_diag("pseudo_append_element: invalid args.\n");
+ return -1;
+ }
+ newpath = *pnewpath;
+ allocated = *pallocated;
+ current = *pcurrent;
+ /* sanity-check: ignore // or /./ */
+ if (elen == 0 || (elen == 1 && *element == '.')) {
+ return 1;
+ }
+ /* backtrack for .. */
+ if (elen == 2 && element[0] == '.' && element[1] == '.') {
+ /* if newpath's whole contents are '/', do nothing */
+ if (current <= newpath + 1)
+ return 1;
+ /* backtrack to the character before the / */
+ current -= 2;
+ /* now find the previous slash */
+ while (current > newpath && *current != '/') {
+ --current;
+ }
+ /* and point to the nul just past it */
+ *(++current) = '\0';
+ *pcurrent = current;
+ return 1;
+ }
+ curlen = current - newpath;
+ /* current length, plus / <element> / \0 */
+ /* => curlen + elen + 3 */
+ if (curlen + elen + 3 > allocated) {
+ char *bigger;
+ size_t big = round_up(allocated + elen, 256);
+ bigger = malloc(big);
+ if (!bigger) {
+ pseudo_diag("pseudo_append_element: couldn't allocate space (wanted %lu bytes).\n", (unsigned long) big);
+ return -1;
+ }
+ memcpy(bigger, newpath, curlen);
+ current = bigger + curlen;
+ free(newpath);
+ newpath = bigger;
+ allocated = big;
+ *pnewpath = newpath;
+ *pcurrent = current;
+ *pallocated = allocated;
+ }
+ memcpy(current, element, elen);
+ current += elen;
+ /* nul-terminate, and we now point to the nul after the slash */
+ *current = '\0';
+ /* now, the moment of truth... is that a symlink? */
+ /* if lstat fails, that's fine -- nonexistent files aren't symlinks */
+ if (!leave_this) {
+ int is_link;
+ is_link = (lstat64(newpath, &buf) != -1) && S_ISLNK(buf.st_mode);
+ if (link_recursion >= PSEUDO_MAX_LINK_RECURSION && is_link) {
+ pseudo_diag("link recursion too deep, not expanding path '%s'.\n", newpath);
+ is_link = 0;
+ }
+ if (is_link) {
+ char linkbuf[PATH_MAX + 1];
+ ssize_t linklen;
+ int retval;
+
+ linklen = readlink(newpath, linkbuf, PATH_MAX);
+ if (linklen == -1) {
+ pseudo_diag("uh-oh! '%s' seems to be a symlink, but I can't read it. Ignoring.", newpath);
+ return 0;
+ }
+ /* null-terminate buffer */
+ linkbuf[linklen] = '\0';
+ /* absolute symlink means start over! */
+ if (*linkbuf == '/') {
+ current = newpath + 1;
+ } else {
+ /* point back at the end of the previous path... */
+ current -= elen;
+ }
+ /* null terminate at the new pointer */
+ *current = '\0';
+ /* append all the elements in series */
+ *pcurrent = current;
+ ++link_recursion;
+ retval = pseudo_append_elements(pnewpath, pallocated, pcurrent, linkbuf, linklen, 0);
+ --link_recursion;
+ return retval;
+ }
+ }
+ /* okay, not a symlink, go ahead and append a slash */
+ *(current++) = '/';
+ *current = '\0';
+ *pcurrent = current;
+ return 1;
+}
+
+static int
+pseudo_append_elements(char **newpath, size_t *allocated, char **current, const char *element, size_t elen, int leave_last) {
+ int retval = 1;
+ const char * start = element;
+ if (!newpath || !current || !element || !*newpath || !*current) {
+ pseudo_diag("pseudo_append_elements: invalid arguments.");
+ return -1;
+ }
+ while (element < (start + elen) && *element) {
+ size_t this_elen;
+ int leave_this = 0;
+ char *next = strchr(element, '/');
+ if (!next) {
+ next = strchr(element, '\0');
+ leave_this = leave_last;
+ }
+ this_elen = next - element;
+ switch (this_elen) {
+ case 0: /* path => '/' */
+ break;
+ case 1: /* path => '?/' */
+ if (*element != '.') {
+ if (pseudo_append_element(newpath, allocated, current, element, this_elen, leave_this) == -1) {
+ retval = -1;
+ }
+ }
+ break;
+ default:
+ if (pseudo_append_element(newpath, allocated, current, element, this_elen, leave_this) == -1) {
+ retval = -1;
+ }
+ break;
+ }
+ /* and now move past the separator */
+ element += this_elen + 1;
+ }
+ return retval;
+}
+
+/* Canonicalize path. "base", if present, is an already-canonicalized
+ * path of baselen characters, presumed not to end in a /. path is
+ * the new path to be canonicalized. The tricky part is that path may
+ * contain symlinks, which must be resolved.
+ * if "path" starts with a /, then it is an absolute path, and
+ * we ignore base.
+ */
+char *
+pseudo_fix_path(char *base, const char *path, size_t baselen, size_t *lenp, int leave_last) {
+ size_t newpathlen, pathlen;
+ char *newpath;
+ char *current;
+
+ if (!path) {
+ pseudo_diag("can't fix empty path.\n");
+ return 0;
+ }
+ pathlen = strlen(path);
+ /* allow a bit of slush. overallocating a bit won't
+ * hurt. rounding to 256's in the hopes that it makes life
+ * easier for the library.
+ */
+ if (path[0] == '/') {
+ newpathlen = round_up(pathlen + 1, 256);
+ newpath = malloc(newpathlen);
+ if (!newpath) {
+ pseudo_diag("allocation failed seeking memory for path (%s).\n", path);
+ return 0;
+ }
+ current = newpath;
+ ++path;
+ } else {
+ newpathlen = round_up(baselen + pathlen + 2, 256);
+ newpath = malloc(newpathlen);
+ memcpy(newpath, base, baselen);
+ current = newpath + baselen;
+ }
+ *current++ = '/';
+ *current = '\0';
+ /* at any given point:
+ * current points to just after the last / of newpath
+ * path points to the next path element of path
+ * newpathlen is the total allocated length of newpath
+ * (current - newpathlen) is the used length of newpath
+ * oldpath is the starting point of path
+ * (path - oldpath) is how far into path we are
+ */
+ if (pseudo_append_elements(&newpath, &newpathlen, &current, path, pathlen, leave_last) != -1) {
+ --current;
+ if (*current == '/') {
+ *current = '\0';
+ }
+ pseudo_debug(3, "%s + %s => <%s>\n",
+ base ? base : "<nil>",
+ path ? path : "<nil>",
+ newpath ? newpath : "<nil>");
+ if (lenp) {
+ *lenp = current - newpath;
+ }
+ return newpath;
+ } else {
+ free(newpath);
+ return 0;
+ }
+}
+
+/* remove the pseudo stuff from the environment (leaving other preloads
+ * alone).
+ */
+void
+pseudo_dropenv(void) {
+ char *ld_env = getenv("LD_PRELOAD");
+
+ /* why do this two ways? Because calling setenv(), then execing,
+ * in bash seems to result in the variables still being set in the
+ * new environment.
+ * we remove the entire LD_PRELOAD, because our use case would have
+ * fakechroot and fakepasswd in it too -- and we don't want that.
+ * we don't touch LD_LIBRARY_PATH because it might be being used for
+ * other system libraries...
+ */
+ if (ld_env) {
+ unsetenv("LD_PRELOAD");
+ }
+}
+
+/* add pseudo stuff to the environment.
+ */
+void
+pseudo_setupenv(char *opts) {
+ char *ld_env;
+ char *newenv;
+ size_t len;
+ char debugvalue[64];
+
+ newenv = "libpseudo.so";
+ setenv("LD_PRELOAD", newenv, 1);
+
+ ld_env = getenv("LD_LIBRARY_PATH");
+ if (ld_env) {
+ char *prefix = pseudo_prefix_path(NULL);
+ if (!strstr(ld_env, prefix)) {
+ char *e1, *e2;
+ e1 = pseudo_prefix_path("lib");
+ e2 = pseudo_prefix_path("lib64");
+ len = strlen(ld_env) + strlen(e1) + strlen(e2) + 3;
+ newenv = malloc(len);
+ snprintf(newenv, len, "%s:%s:%s", ld_env, e1, e2);
+ free(e1);
+ free(e2);
+ setenv("LD_LIBRARY_PATH", newenv, 1);
+ free(newenv);
+ }
+ free(prefix);
+ } else {
+ char *e1, *e2;
+ e1 = pseudo_prefix_path("lib");
+ e2 = pseudo_prefix_path("lib64");
+ len = strlen(e1) + strlen(e2) + 2;
+ newenv = malloc(len);
+ snprintf(newenv, len, "%s:%s", e1, e2);
+ setenv("LD_LIBRARY_PATH", newenv, 1);
+ free(newenv);
+ }
+
+ if (max_debug_level) {
+ sprintf(debugvalue, "%d", max_debug_level);
+ setenv("PSEUDO_DEBUG", debugvalue, 1);
+ } else {
+ unsetenv("PSEUDO_DEBUG");
+ }
+
+ if (opts) {
+ setenv("PSEUDO_OPTS", opts, 1);
+ } else {
+ unsetenv("PSEUDO_OPTS");
+ }
+}
+
+/* get the full path to a file under $PSEUDO_PREFIX. Other ways of
+ * setting the prefix all set it in the environment.
+ */
+char *
+pseudo_prefix_path(char *s) {
+ static char *prefix = NULL;
+ static size_t prefix_len;
+ char *path;
+
+ if (!prefix) {
+ prefix = getenv("PSEUDO_PREFIX");
+ if (!prefix) {
+ pseudo_diag("You must set the PSEUDO_PREFIX environment variable to run pseudo.\n");
+ exit(1);
+ }
+ prefix_len = strlen(prefix);
+ while ((prefix[prefix_len - 1] == '/') && (prefix_len > 0)) {
+ prefix[--prefix_len] = '\0';
+ }
+ }
+ if (!s) {
+ return strdup(prefix);
+ } else {
+ size_t len = prefix_len + strlen(s) + 2;
+ path = malloc(len);
+ if (path) {
+ snprintf(path, len, "%s/%s", prefix, s);
+ }
+ return path;
+ }
+}
+
+char *
+pseudo_get_prefix(char *pathname) {
+ char *s;
+ s = getenv("PSEUDO_PREFIX");
+ if (!s) {
+ char mypath[PATH_MAX];
+ char *dir;
+ char *tmp_path;
+
+ if (pathname[0] == '/') {
+ snprintf(mypath, PATH_MAX, "%s", pathname);
+ s = mypath + strlen(mypath);
+ } else {
+ if (!getcwd(mypath, PATH_MAX)) {
+ mypath[0] = '\0';
+ }
+ s = mypath + strlen(mypath);
+ s += snprintf(s, PATH_MAX - (s - mypath), "/%s",
+ pathname);
+ }
+ tmp_path = pseudo_fix_path(NULL, mypath, 0, 0, 0);
+ /* point s to the end of the fixed path */
+ if (strlen(tmp_path) >= PATH_MAX) {
+ pseudo_diag("Can't expand path '%s' -- expansion exceeds PATH_MAX.\n",
+ mypath);
+ free(tmp_path);
+ } else {
+ s = mypath + snprintf(mypath, PATH_MAX, "%s", tmp_path);
+ free(tmp_path);
+ }
+
+ while (s > (mypath + 1) && *s != '/')
+ --s;
+ *s = '\0';
+ dir = s - 1;
+ while (dir > mypath && *dir != '/') {
+ --dir;
+ }
+ /* strip bin directory, if any */
+ if (!strncmp(dir, "/bin", 4)) {
+ *dir = '\0';
+ }
+ /* degenerate case: /bin/pseudo should yield a pseudo_prefix "/" */
+ if (*mypath == '\0') {
+ strcpy(mypath, "/");
+ }
+
+ pseudo_diag("Warning: PSEUDO_PREFIX unset, defaulting to %s.\n",
+ mypath);
+ setenv("PSEUDO_PREFIX", mypath, 1);
+ s = getenv("PSEUDO_PREFIX");
+ }
+ return s;
+}
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