freebsd-dev/libexec/rtld-elf/libmap.c
Dag-Erling Smørgrav 8182b3bee1 Make the directory mapping functionality, which was previously only
available in 32-bit compatibility mode, unconditional.

Overhaul the man page, which had evolved more by accretion than by design.

Approved by:	re (gjb)
MFC after:	3 weeks
2013-09-21 21:03:52 +00:00

479 lines
9.3 KiB
C

/*
* $FreeBSD$
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/mman.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "debug.h"
#include "rtld.h"
#include "libmap.h"
#ifndef _PATH_LIBMAP_CONF
#define _PATH_LIBMAP_CONF "/etc/libmap.conf"
#endif
#ifdef COMPAT_32BIT
#undef _PATH_LIBMAP_CONF
#define _PATH_LIBMAP_CONF "/etc/libmap32.conf"
#endif
TAILQ_HEAD(lm_list, lm);
struct lm {
char *f;
char *t;
TAILQ_ENTRY(lm) lm_link;
};
TAILQ_HEAD(lmp_list, lmp) lmp_head = TAILQ_HEAD_INITIALIZER(lmp_head);
struct lmp {
char *p;
enum { T_EXACT=0, T_BASENAME, T_DIRECTORY } type;
struct lm_list lml;
TAILQ_ENTRY(lmp) lmp_link;
};
static TAILQ_HEAD(lmc_list, lmc) lmc_head = TAILQ_HEAD_INITIALIZER(lmc_head);
struct lmc {
char *path;
TAILQ_ENTRY(lmc) next;
};
static int lm_count;
static void lmc_parse(char *, size_t);
static void lmc_parse_file(char *);
static void lmc_parse_dir(char *);
static void lm_add(const char *, const char *, const char *);
static void lm_free(struct lm_list *);
static char *lml_find(struct lm_list *, const char *);
static struct lm_list *lmp_find(const char *);
static struct lm_list *lmp_init(char *);
static const char *quickbasename(const char *);
#define iseol(c) (((c) == '#') || ((c) == '\0') || \
((c) == '\n') || ((c) == '\r'))
/*
* Do not use ctype.h macros, which rely on working TLS. It is
* too early to have thread-local variables functional.
*/
#define rtld_isspace(c) ((c) == ' ' || (c) == '\t')
int
lm_init(char *libmap_override)
{
char *p;
dbg("lm_init(\"%s\")", libmap_override);
TAILQ_INIT(&lmp_head);
lmc_parse_file(_PATH_LIBMAP_CONF);
if (libmap_override) {
/*
* Do some character replacement to make $LIBMAP look
* like a text file, then parse it.
*/
libmap_override = xstrdup(libmap_override);
for (p = libmap_override; *p; p++) {
switch (*p) {
case '=':
*p = ' ';
break;
case ',':
*p = '\n';
break;
}
}
lmc_parse(p, strlen(p));
free(p);
}
return (lm_count == 0);
}
static void
lmc_parse_file(char *path)
{
struct lmc *p;
struct stat st;
int fd;
char *rpath;
char *lm_map;
rpath = realpath(path, NULL);
if (rpath == NULL)
return;
TAILQ_FOREACH(p, &lmc_head, next) {
if (strcmp(p->path, rpath) == 0) {
free(rpath);
return;
}
}
fd = open(rpath, O_RDONLY | O_CLOEXEC);
if (fd == -1) {
dbg("lm_parse_file: open(\"%s\") failed, %s", rpath,
rtld_strerror(errno));
free(rpath);
return;
}
if (fstat(fd, &st) == -1) {
close(fd);
dbg("lm_parse_file: fstat(\"%s\") failed, %s", rpath,
rtld_strerror(errno));
free(rpath);
return;
}
lm_map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (lm_map == (const char *)MAP_FAILED) {
close(fd);
dbg("lm_parse_file: mmap(\"%s\") failed, %s", rpath,
rtld_strerror(errno));
free(rpath);
return;
}
close(fd);
p = xmalloc(sizeof(struct lmc));
p->path = rpath;
TAILQ_INSERT_HEAD(&lmc_head, p, next);
lmc_parse(lm_map, st.st_size);
munmap(lm_map, st.st_size);
}
static void
lmc_parse_dir(char *idir)
{
DIR *d;
struct dirent *dp;
struct lmc *p;
char conffile[MAXPATHLEN];
char *ext;
char *rpath;
rpath = realpath(idir, NULL);
if (rpath == NULL)
return;
TAILQ_FOREACH(p, &lmc_head, next) {
if (strcmp(p->path, rpath) == 0) {
free(rpath);
return;
}
}
d = opendir(idir);
if (d == NULL) {
free(rpath);
return;
}
p = xmalloc(sizeof(struct lmc));
p->path = rpath;
TAILQ_INSERT_HEAD(&lmc_head, p, next);
while ((dp = readdir(d)) != NULL) {
if (dp->d_ino == 0)
continue;
if (dp->d_type != DT_REG)
continue;
ext = strrchr(dp->d_name, '.');
if (ext == NULL)
continue;
if (strcmp(ext, ".conf") != 0)
continue;
if (strlcpy(conffile, idir, MAXPATHLEN) >= MAXPATHLEN)
continue; /* too long */
if (strlcat(conffile, "/", MAXPATHLEN) >= MAXPATHLEN)
continue; /* too long */
if (strlcat(conffile, dp->d_name, MAXPATHLEN) >= MAXPATHLEN)
continue; /* too long */
lmc_parse_file(conffile);
}
closedir(d);
}
static void
lmc_parse(char *lm_p, size_t lm_len)
{
char *cp, *f, *t, *c, *p;
char prog[MAXPATHLEN];
/* allow includedir + full length path */
char line[MAXPATHLEN + 13];
size_t cnt;
int i;
cnt = 0;
p = NULL;
while (cnt < lm_len) {
i = 0;
while (lm_p[cnt] != '\n' && cnt < lm_len &&
i < sizeof(line) - 1) {
line[i] = lm_p[cnt];
cnt++;
i++;
}
line[i] = '\0';
while (lm_p[cnt] != '\n' && cnt < lm_len)
cnt++;
/* skip over nl */
cnt++;
cp = &line[0];
t = f = c = NULL;
/* Skip over leading space */
while (rtld_isspace(*cp)) cp++;
/* Found a comment or EOL */
if (iseol(*cp)) continue;
/* Found a constraint selector */
if (*cp == '[') {
cp++;
/* Skip leading space */
while (rtld_isspace(*cp)) cp++;
/* Found comment, EOL or end of selector */
if (iseol(*cp) || *cp == ']')
continue;
c = cp++;
/* Skip to end of word */
while (!rtld_isspace(*cp) && !iseol(*cp) && *cp != ']')
cp++;
/* Skip and zero out trailing space */
while (rtld_isspace(*cp)) *cp++ = '\0';
/* Check if there is a closing brace */
if (*cp != ']') continue;
/* Terminate string if there was no trailing space */
*cp++ = '\0';
/*
* There should be nothing except whitespace or comment
from this point to the end of the line.
*/
while(rtld_isspace(*cp)) cp++;
if (!iseol(*cp)) continue;
if (strlcpy(prog, c, sizeof prog) >= sizeof prog)
continue;
p = prog;
continue;
}
/* Parse the 'from' candidate. */
f = cp++;
while (!rtld_isspace(*cp) && !iseol(*cp)) cp++;
/* Skip and zero out the trailing whitespace */
while (rtld_isspace(*cp)) *cp++ = '\0';
/* Found a comment or EOL */
if (iseol(*cp)) continue;
/* Parse 'to' mapping */
t = cp++;
while (!rtld_isspace(*cp) && !iseol(*cp)) cp++;
/* Skip and zero out the trailing whitespace */
while (rtld_isspace(*cp)) *cp++ = '\0';
/* Should be no extra tokens at this point */
if (!iseol(*cp)) continue;
*cp = '\0';
if (strcmp(f, "includedir") == 0)
lmc_parse_dir(t);
else if (strcmp(f, "include") == 0)
lmc_parse_file(t);
else
lm_add(p, f, t);
}
}
static void
lm_free (struct lm_list *lml)
{
struct lm *lm;
dbg("%s(%p)", __func__, lml);
while (!TAILQ_EMPTY(lml)) {
lm = TAILQ_FIRST(lml);
TAILQ_REMOVE(lml, lm, lm_link);
free(lm->f);
free(lm->t);
free(lm);
}
return;
}
void
lm_fini (void)
{
struct lmp *lmp;
struct lmc *p;
dbg("%s()", __func__);
while (!TAILQ_EMPTY(&lmc_head)) {
p = TAILQ_FIRST(&lmc_head);
TAILQ_REMOVE(&lmc_head, p, next);
free(p->path);
free(p);
}
while (!TAILQ_EMPTY(&lmp_head)) {
lmp = TAILQ_FIRST(&lmp_head);
TAILQ_REMOVE(&lmp_head, lmp, lmp_link);
free(lmp->p);
lm_free(&lmp->lml);
free(lmp);
}
return;
}
static void
lm_add (const char *p, const char *f, const char *t)
{
struct lm_list *lml;
struct lm *lm;
if (p == NULL)
p = "$DEFAULT$";
dbg("%s(\"%s\", \"%s\", \"%s\")", __func__, p, f, t);
if ((lml = lmp_find(p)) == NULL)
lml = lmp_init(xstrdup(p));
lm = xmalloc(sizeof(struct lm));
lm->f = xstrdup(f);
lm->t = xstrdup(t);
TAILQ_INSERT_HEAD(lml, lm, lm_link);
lm_count++;
}
char *
lm_find (const char *p, const char *f)
{
struct lm_list *lml;
char *t;
dbg("%s(\"%s\", \"%s\")", __func__, p, f);
if (p != NULL && (lml = lmp_find(p)) != NULL) {
t = lml_find(lml, f);
if (t != NULL) {
/*
* Add a global mapping if we have
* a successful constrained match.
*/
lm_add(NULL, f, t);
return (t);
}
}
lml = lmp_find("$DEFAULT$");
if (lml != NULL)
return (lml_find(lml, f));
else
return (NULL);
}
/* Given a libmap translation list and a library name, return the
replacement library, or NULL */
char *
lm_findn (const char *p, const char *f, const int n)
{
char pathbuf[64], *s, *t;
if (n < sizeof(pathbuf) - 1)
s = pathbuf;
else
s = xmalloc(n + 1);
memcpy(s, f, n);
s[n] = '\0';
t = lm_find(p, s);
if (s != pathbuf)
free(s);
return (t);
}
static char *
lml_find (struct lm_list *lmh, const char *f)
{
struct lm *lm;
dbg("%s(%p, \"%s\")", __func__, lmh, f);
TAILQ_FOREACH(lm, lmh, lm_link)
if (strcmp(f, lm->f) == 0)
return (lm->t);
return (NULL);
}
/* Given an executable name, return a pointer to the translation list or
NULL if no matches */
static struct lm_list *
lmp_find (const char *n)
{
struct lmp *lmp;
dbg("%s(\"%s\")", __func__, n);
TAILQ_FOREACH(lmp, &lmp_head, lmp_link)
if ((lmp->type == T_EXACT && strcmp(n, lmp->p) == 0) ||
(lmp->type == T_DIRECTORY && strncmp(n, lmp->p, strlen(lmp->p)) == 0) ||
(lmp->type == T_BASENAME && strcmp(quickbasename(n), lmp->p) == 0))
return (&lmp->lml);
return (NULL);
}
static struct lm_list *
lmp_init (char *n)
{
struct lmp *lmp;
dbg("%s(\"%s\")", __func__, n);
lmp = xmalloc(sizeof(struct lmp));
lmp->p = n;
if (n[strlen(n)-1] == '/')
lmp->type = T_DIRECTORY;
else if (strchr(n,'/') == NULL)
lmp->type = T_BASENAME;
else
lmp->type = T_EXACT;
TAILQ_INIT(&lmp->lml);
TAILQ_INSERT_HEAD(&lmp_head, lmp, lmp_link);
return (&lmp->lml);
}
/* libc basename is overkill. Return a pointer to the character after the
last /, or the original string if there are no slashes. */
static const char *
quickbasename (const char *path)
{
const char *p = path;
for (; *path; path++) {
if (*path == '/')
p = path+1;
}
return (p);
}