add a do_realpath() implementation replacing the use of the external
libc function realpath(3) which may not be available on the target system; compile the realpath builtin unconditionally looks fine to me, but review is appreciated; this is (very) lightly based upon MirBSD libc’s realpath(3) and pdksh’s get_phys_path()
This commit is contained in:
tg
162
funcs.c
162
funcs.c
@ -25,7 +25,7 @@
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#include "sh.h"
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__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.125 2009/08/28 21:51:51 tg Exp $");
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__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.126 2009/08/30 13:22:38 tg Exp $");
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#if HAVE_KILLPG
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/*
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@ -102,9 +102,7 @@ const struct builtin mkshbuiltins[] = {
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#if HAVE_MKNOD
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{"mknod", c_mknod},
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#endif
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#if HAVE_REALPATH
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{"realpath", c_realpath},
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#endif
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{"rename", c_rename},
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{NULL, (int (*)(const char **))NULL}
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};
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@ -173,6 +171,146 @@ static void ptest_error(Test_env *, int, const char *);
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static char *kill_fmt_entry(const void *, int, char *, int);
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static void p_time(struct shf *, bool, long, int, int,
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const char *, const char *) __attribute__((nonnull (6, 7)));
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static char *do_realpath(const char *);
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static char *
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do_realpath(const char *upath)
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{
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char *xp, *ip, *tp, *ipath, *ldest = NULL;
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XString xs;
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ptrdiff_t pos;
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size_t len;
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int symlinks = 32; /* max. recursion depth */
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int llen;
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struct stat sb;
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if (upath[0] == '/') {
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/* upath is an absolute pathname */
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strdupx(ipath, upath, ATEMP);
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} else {
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/* upath is a relative pathname, prepend cwd */
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if ((tp = ksh_get_wd(NULL)) == NULL || tp[0] != '/')
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return (NULL);
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ipath = shf_smprintf("%s/%s", tp, upath);
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afree(tp, ATEMP);
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}
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Xinit(xs, xp, strlen(ip = ipath) + 1, ATEMP);
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while (*ip) {
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/* skip slashes in input */
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while (*ip == '/')
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++ip;
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if (!*ip)
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break;
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/* get next pathname component from input */
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tp = ip;
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while (*ip && *ip != '/')
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++ip;
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len = ip - tp;
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/* check input for "." and ".." */
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if (tp[0] == '.') {
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if (len == 1)
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/* just continue with the next one */
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continue;
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else if (len == 2 && tp[1] == '.') {
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/* strip off last pathname component */
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while (xp > Xstring(xs, xp))
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if (*--xp == '/')
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break;
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/* then continue with the next one */
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continue;
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}
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}
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/* store output position away, then append slash to output */
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pos = Xsavepos(xs, xp);
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Xcheck(xs, xp);
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Xput(xs, xp, '/');
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/* append next pathname component to output */
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XcheckN(xs, xp, len + 1);
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memcpy(xp, tp, len);
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xp += len;
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*xp = '\0';
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/* lstat the current output, see if it's a symlink */
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if (lstat(Xstring(xs, xp), &sb)) {
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/* lstat failed */
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if (errno == ENOENT) {
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/* because the pathname does not exist */
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while (*ip == '/')
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/* skip any trailing slashes */
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++ip;
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/* no more components left? */
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if (!*ip)
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/* we can still return successfully */
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break;
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/* more components left? fall through */
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}
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/* not ENOENT or not at the end of ipath */
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goto notfound;
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}
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/* check if we encountered a symlink? */
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if (S_ISLNK(sb.st_mode)) {
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/* reached maximum recursion depth? */
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if (!symlinks--) {
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/* yep, prevent infinite loops */
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errno = ELOOP;
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goto notfound;
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}
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/* get symlink(7) target */
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if (!ldest)
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ldest = alloc(PATH_MAX + 1, ATEMP);
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if ((llen = readlink(Xstring(xs, xp), ldest,
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PATH_MAX)) < 0)
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/* oops... */
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goto notfound;
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ldest[llen] = '\0';
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/*
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* restart if symlink target is an absolute path,
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* otherwise continue with currently resolved prefix
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*/
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xp = (ldest[0] == '/') ? Xstring(xs, xp) :
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Xrestpos(xs, xp, pos);
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tp = shf_smprintf("%s/%s", ldest, ip);
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afree(ipath, ATEMP);
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ip = ipath = tp;
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}
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/* otherwise (no symlink) merely go on */
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}
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/*
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* either found the target and successfully resolved it,
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* or found its parent directory and may create it
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*/
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if (Xlength(xs, xp) == 0)
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/*
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* if the resolved pathname is "", make it "/",
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* otherwise do not add a trailing slash
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*/
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Xput(xs, xp, '/');
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Xput(xs, xp, '\0');
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if (ldest != NULL)
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afree(ldest, ATEMP);
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afree(ipath, ATEMP);
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return (Xclose(xs, xp));
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notfound:
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llen = errno; /* save; free(3) might trash it */
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if (ldest != NULL)
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afree(ldest, ATEMP);
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afree(ipath, ATEMP);
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Xfree(xs, xp);
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errno = llen;
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return (NULL);
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}
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int
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c_cd(const char **wp)
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@ -3124,11 +3262,11 @@ c_rename(const char **wp)
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return (rv);
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}
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#if HAVE_REALPATH
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int
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c_realpath(const char **wp)
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{
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int rv = 1;
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char *buf;
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if (wp != NULL && wp[0] != NULL && wp[1] != NULL) {
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if (strcmp(wp[1], "--")) {
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@ -3146,17 +3284,15 @@ c_realpath(const char **wp)
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if (rv)
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bi_errorf(T_synerr);
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else {
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char *buf;
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if (realpath(*wp, (buf = alloc(PATH_MAX, ATEMP))) == NULL) {
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rv = errno;
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bi_errorf("%s: %s", *wp, strerror(rv));
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} else
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shprintf("%s\n", buf);
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else if ((buf = do_realpath(*wp)) == NULL) {
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rv = errno;
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bi_errorf("%s: %s", *wp, strerror(rv));
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if ((unsigned int)rv > 255)
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rv = 255;
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} else {
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shprintf("%s\n", buf);
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afree(buf, ATEMP);
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}
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return (rv);
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}
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#endif
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