freebsd-skq/sbin/ldconfig/elfhints.c
jdp 6c76bd6d54 Implement ldconfig functionality for ELF. The hints are stored in
a different file than the a.out hints, namely, "/var/run/ld-elf.so.hints".
These hints consist only of the directory search path.  There is
no hash table as in the a.out hints, because ELF doesn't have to
search for the file with the highest minor version number.  (It
doesn't have minor version numbers at all.)

A single run of ldconfig updates either the a.out hints or the ELF
hints, but not both.  The set of hints to process is selected in
the usual way, via /etc/objformat, or ${OBJFORMAT}, or the "-aout"
or "-elf" command line option.  The rationale is that you probably
want to search different directories for ELF than for a.out.

"ldconfig -r" is faked up to produce output like we are used to,
except that for ELF there are no minor version numbers.  This should
enable "ldconfig -r" to be used for checking LIB_DEPENDS in ports
even for ELF.

I implemented the ELF functionality in a new source file, with an
eye toward eliminating the a.out code entirely at some point in
the future.
1998-09-05 03:31:00 +00:00

281 lines
7.1 KiB
C

/*-
* Copyright (c) 1998 John D. Polstra
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
*/
#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <ctype.h>
#include <dirent.h>
#include <elf.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "ldconfig.h"
#define MAXDIRS 1024 /* Maximum directories in path */
#define MAXFILESIZE (16*1024) /* Maximum hints file size */
static void add_dir(const char *, const char *);
static void read_dirs_from_file(const char *, const char *);
static void read_elf_hints(const char *, int);
static void write_elf_hints(const char *);
static const char *dirs[MAXDIRS];
static int ndirs;
static void
add_dir(const char *hintsfile, const char *name)
{
int i;
for (i = 0; i < ndirs; i++)
if (strcmp(dirs[i], name) == 0)
return;
if (ndirs >= MAXDIRS)
errx(1, "\"%s\": Too many directories in path", hintsfile);
dirs[ndirs++] = name;
}
void
list_elf_hints(const char *hintsfile)
{
int i;
int nlibs;
read_elf_hints(hintsfile, 1);
printf("%s:\n", hintsfile);
printf("\tsearch directories:");
for (i = 0; i < ndirs; i++)
printf("%c%s", i == 0 ? ' ' : ':', dirs[i]);
printf("\n");
nlibs = 0;
for (i = 0; i < ndirs; i++) {
DIR *dirp;
struct dirent *dp;
if ((dirp = opendir(dirs[i])) == NULL)
continue;
while ((dp = readdir(dirp)) != NULL) {
int len;
int namelen;
const char *name;
const char *vers;
/* Name can't be shorter than "libx.so.0" */
if ((len = strlen(dp->d_name)) < 9 ||
strncmp(dp->d_name, "lib", 3) != 0)
continue;
name = dp->d_name + 3;
vers = dp->d_name + len;
while (vers > dp->d_name && isdigit(*(vers-1)))
vers--;
if (vers == dp->d_name + len)
continue;
if (vers < dp->d_name + 4 ||
strncmp(vers - 4, ".so.", 4) != 0)
continue;
/* We have a valid shared library name. */
namelen = (vers - 4) - name;
printf("\t%d:-l%.*s.%s => %s/%s\n", nlibs,
namelen, name, vers, dirs[i], dp->d_name);
nlibs++;
}
closedir(dirp);
}
}
static void
read_dirs_from_file(const char *hintsfile, const char *listfile)
{
FILE *fp;
char buf[MAXPATHLEN];
int linenum;
if ((fp = fopen(listfile, "r")) == NULL)
err(1, "%s", listfile);
linenum = 0;
while (fgets(buf, sizeof buf, fp) != NULL) {
char *cp, *sp;
linenum++;
cp = buf;
/* Skip leading white space. */
while (isspace(*cp))
cp++;
if (*cp == '#' || *cp == '\0')
continue;
sp = cp;
/* Advance over the directory name. */
while (!isspace(*cp) && *cp != '\0')
cp++;
/* Terminate the string and skip trailing white space. */
if (*cp != '\0') {
*cp++ = '\0';
while (isspace(*cp))
cp++;
}
/* Now we had better be at the end of the line. */
if (*cp != '\0')
warnx("%s:%d: trailing characters ignored",
listfile, linenum);
if ((sp = strdup(sp)) == NULL)
errx(1, "Out of memory");
add_dir(hintsfile, sp);
}
fclose(fp);
}
static void
read_elf_hints(const char *hintsfile, int must_exist)
{
int fd;
struct stat s;
void *mapbase;
struct elfhints_hdr *hdr;
char *strtab;
char *dirlist;
char *p;
if ((fd = open(hintsfile, O_RDONLY)) == -1) {
if (errno == ENOENT && !must_exist)
return;
err(1, "Cannot open \"%s\"", hintsfile);
}
if (fstat(fd, &s) == -1)
err(1, "Cannot stat \"%s\"", hintsfile);
if (s.st_size > MAXFILESIZE)
errx(1, "\"%s\" is unreasonably large", hintsfile);
/*
* We use a read-write, private mapping so that we can null-terminate
* some strings in it without affecting the underlying file.
*/
mapbase = mmap(NULL, s.st_size, PROT_READ|PROT_WRITE,
MAP_PRIVATE, fd, 0);
if (mapbase == MAP_FAILED)
err(1, "Cannot mmap \"%s\"", hintsfile);
close(fd);
hdr = (struct elfhints_hdr *)mapbase;
if (hdr->magic != ELFHINTS_MAGIC)
errx(1, "\"%s\": invalid file format", hintsfile);
if (hdr->version != 1)
errx(1, "\"%s\": unrecognized file version (%d)", hintsfile,
hdr->version);
strtab = (char *)mapbase + hdr->strtab;
dirlist = strtab + hdr->dirlist;
if (*dirlist != '\0')
while ((p = strsep(&dirlist, ":")) != NULL)
add_dir(hintsfile, p);
}
void
update_elf_hints(const char *hintsfile, int argc, char **argv, int merge)
{
int i;
if (merge)
read_elf_hints(hintsfile, 0);
for (i = 0; i < argc; i++) {
struct stat s;
if (stat(argv[i], &s) == -1)
err(1, "%s", argv[i]);
if (S_ISREG(s.st_mode))
read_dirs_from_file(hintsfile, argv[i]);
else
add_dir(hintsfile, argv[i]);
}
write_elf_hints(hintsfile);
}
static void
write_elf_hints(const char *hintsfile)
{
struct elfhints_hdr hdr;
char *tempname;
int fd;
FILE *fp;
int i;
if (asprintf(&tempname, "%s.XXXXXX", hintsfile) == -1)
errx(1, "Out of memory");
if ((fd = mkstemp(tempname)) == -1)
err(1, "mkstemp(%s)", tempname);
if (fchmod(fd, 0444) == -1)
err(1, "fchmod(%s)", tempname);
if ((fp = fdopen(fd, "wb")) == NULL)
err(1, "fdopen(%s)", tempname);
hdr.magic = ELFHINTS_MAGIC;
hdr.version = 1;
hdr.strtab = sizeof hdr;
hdr.strsize = 0;
hdr.dirlist = 0;
memset(hdr.spare, 0, sizeof hdr.spare);
/* Count up the size of the string table. */
if (ndirs > 0) {
hdr.strsize += strlen(dirs[0]);
for (i = 1; i < ndirs; i++)
hdr.strsize += 1 + strlen(dirs[i]);
}
hdr.dirlistlen = hdr.strsize;
hdr.strsize++; /* For the null terminator */
/* Write the header. */
if (fwrite(&hdr, 1, sizeof hdr, fp) != sizeof hdr)
err(1, "%s: write error", tempname);
/* Write the strings. */
if (ndirs > 0) {
if (fputs(dirs[0], fp) == EOF)
err(1, "%s: write error", tempname);
for (i = 1; i < ndirs; i++)
if (fprintf(fp, ":%s", dirs[i]) < 0)
err(1, "%s: write error", tempname);
}
if (putc('\0', fp) == EOF || fclose(fp) == EOF)
err(1, "%s: write error", tempname);
if (rename(tempname, hintsfile) == -1)
err(1, "rename %s to %s", tempname, hintsfile);
free(tempname);
}