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-rw-r--r--lib/sh/pathphys.c296
1 files changed, 296 insertions, 0 deletions
diff --git a/lib/sh/pathphys.c b/lib/sh/pathphys.c
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--- /dev/null
+++ b/lib/sh/pathphys.c
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+/* pathphys.c -- return pathname with all symlinks expanded. */
+
+/* Copyright (C) 2000-2020 Free Software Foundation, Inc.
+
+ This file is part of GNU Bash, the Bourne Again SHell.
+
+ Bash is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ Bash 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
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with Bash. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <config.h>
+
+#include <bashtypes.h>
+#if defined (HAVE_SYS_PARAM_H)
+# include <sys/param.h>
+#endif
+#include <posixstat.h>
+
+#if defined (HAVE_UNISTD_H)
+# include <unistd.h>
+#endif
+
+#include <filecntl.h>
+#include <bashansi.h>
+#include <stdio.h>
+#include <chartypes.h>
+#include <errno.h>
+
+#include "shell.h"
+
+#if !defined (MAXSYMLINKS)
+# define MAXSYMLINKS 32
+#endif
+
+#if !defined (errno)
+extern int errno;
+#endif /* !errno */
+
+extern char *get_working_directory PARAMS((char *));
+
+static int
+_path_readlink (path, buf, bufsiz)
+ char *path;
+ char *buf;
+ int bufsiz;
+{
+#ifdef HAVE_READLINK
+ return readlink (path, buf, bufsiz);
+#else
+ errno = EINVAL;
+ return -1;
+#endif
+}
+
+/* Look for ROOTEDPATH, PATHSEP, DIRSEP, and ISDIRSEP in ../../general.h */
+
+#define DOUBLE_SLASH(p) ((p[0] == '/') && (p[1] == '/') && p[2] != '/')
+
+/*
+ * Return PATH with all symlinks expanded in newly-allocated memory.
+ * This always gets an absolute pathname.
+ */
+
+char *
+sh_physpath (path, flags)
+ char *path;
+ int flags;
+{
+ char tbuf[PATH_MAX+1], linkbuf[PATH_MAX+1];
+ char *result, *p, *q, *qsave, *qbase, *workpath;
+ int double_slash_path, linklen, nlink;
+
+ linklen = strlen (path);
+
+#if 0
+ /* First sanity check -- punt immediately if the name is too long. */
+ if (linklen >= PATH_MAX)
+ return (savestring (path));
+#endif
+
+ nlink = 0;
+ q = result = (char *)xmalloc (PATH_MAX + 1);
+
+ /* Even if we get something longer than PATH_MAX, we might be able to
+ shorten it, so we try. */
+ if (linklen >= PATH_MAX)
+ workpath = savestring (path);
+ else
+ {
+ workpath = (char *)xmalloc (PATH_MAX + 1);
+ strcpy (workpath, path);
+ }
+
+ /* This always gets an absolute pathname. */
+
+ /* POSIX.2 says to leave a leading `//' alone. On cygwin, we skip over any
+ leading `x:' (dos drive name). */
+#if defined (__CYGWIN__)
+ qbase = (ISALPHA((unsigned char)workpath[0]) && workpath[1] == ':') ? workpath + 3 : workpath + 1;
+#else
+ qbase = workpath + 1;
+#endif
+ double_slash_path = DOUBLE_SLASH (workpath);
+ qbase += double_slash_path;
+
+ for (p = workpath; p < qbase; )
+ *q++ = *p++;
+ qbase = q;
+
+ /*
+ * invariants:
+ * qbase points to the portion of the result path we want to modify
+ * p points at beginning of path element we're considering.
+ * q points just past the last path element we wrote (no slash).
+ *
+ * XXX -- need to fix error checking for too-long pathnames
+ */
+
+ while (*p)
+ {
+ if (ISDIRSEP(p[0])) /* null element */
+ p++;
+ else if(p[0] == '.' && PATHSEP(p[1])) /* . and ./ */
+ p += 1; /* don't count the separator in case it is nul */
+ else if (p[0] == '.' && p[1] == '.' && PATHSEP(p[2])) /* .. and ../ */
+ {
+ p += 2; /* skip `..' */
+ if (q > qbase)
+ {
+ while (--q > qbase && ISDIRSEP(*q) == 0)
+ ;
+ }
+ }
+ else /* real path element */
+ {
+ /* add separator if not at start of work portion of result */
+ qsave = q;
+ if (q != qbase)
+ *q++ = DIRSEP;
+ while (*p && (ISDIRSEP(*p) == 0))
+ {
+ if (q - result >= PATH_MAX)
+ {
+#ifdef ENAMETOOLONG
+ errno = ENAMETOOLONG;
+#else
+ errno = EINVAL;
+#endif
+ goto error;
+ }
+
+ *q++ = *p++;
+ }
+
+ *q = '\0';
+
+ linklen = _path_readlink (result, linkbuf, PATH_MAX);
+ if (linklen < 0) /* if errno == EINVAL, it's not a symlink */
+ {
+ if (errno != EINVAL)
+ goto error;
+ continue;
+ }
+
+ /* It's a symlink, and the value is in LINKBUF. */
+ nlink++;
+ if (nlink > MAXSYMLINKS)
+ {
+#ifdef ELOOP
+ errno = ELOOP;
+#else
+ errno = EINVAL;
+#endif
+error:
+ free (result);
+ free (workpath);
+ return ((char *)NULL);
+ }
+
+ linkbuf[linklen] = '\0';
+
+ /* If the new path length would overrun PATH_MAX, punt now. */
+ if ((strlen (p) + linklen + 2) >= PATH_MAX)
+ {
+#ifdef ENAMETOOLONG
+ errno = ENAMETOOLONG;
+#else
+ errno = EINVAL;
+#endif
+ goto error;
+ }
+
+ /* Form the new pathname by copying the link value to a temporary
+ buffer and appending the rest of `workpath'. Reset p to point
+ to the start of the rest of the path. If the link value is an
+ absolute pathname, reset p, q, and qbase. If not, reset p
+ and q. */
+ strcpy (tbuf, linkbuf);
+ tbuf[linklen] = '/';
+ strcpy (tbuf + linklen, p);
+ strcpy (workpath, tbuf);
+
+ if (ABSPATH(linkbuf))
+ {
+ q = result;
+ /* Duplicating some code here... */
+#if defined (__CYGWIN__)
+ qbase = (ISALPHA((unsigned char)workpath[0]) && workpath[1] == ':') ? workpath + 3 : workpath + 1;
+#else
+ qbase = workpath + 1;
+#endif
+ double_slash_path = DOUBLE_SLASH (workpath);
+ qbase += double_slash_path;
+
+ for (p = workpath; p < qbase; )
+ *q++ = *p++;
+ qbase = q;
+ }
+ else
+ {
+ p = workpath;
+ q = qsave;
+ }
+ }
+ }
+
+ *q = '\0';
+ free (workpath);
+
+ /* If the result starts with `//', but the original path does not, we
+ can turn the // into /. Because of how we set `qbase', this should never
+ be true, but it's a sanity check. */
+ if (DOUBLE_SLASH(result) && double_slash_path == 0)
+ {
+ if (result[2] == '\0') /* short-circuit for bare `//' */
+ result[1] = '\0';
+ else
+ memmove (result, result + 1, strlen (result + 1) + 1);
+ }
+
+ return (result);
+}
+
+char *
+sh_realpath (pathname, resolved)
+ const char *pathname;
+ char *resolved;
+{
+ char *tdir, *wd;
+
+ if (pathname == 0 || *pathname == '\0')
+ {
+ errno = (pathname == 0) ? EINVAL : ENOENT;
+ return ((char *)NULL);
+ }
+
+ if (ABSPATH (pathname) == 0)
+ {
+ wd = get_working_directory ("sh_realpath");
+ if (wd == 0)
+ return ((char *)NULL);
+ tdir = sh_makepath (wd, (char *)pathname, 0);
+ free (wd);
+ }
+ else
+ tdir = savestring (pathname);
+
+ wd = sh_physpath (tdir, 0);
+ free (tdir);
+
+ if (resolved == 0)
+ return (wd);
+
+ if (wd)
+ {
+ strncpy (resolved, wd, PATH_MAX - 1);
+ resolved[PATH_MAX - 1] = '\0';
+ free (wd);
+ return resolved;
+ }
+ else
+ {
+ resolved[0] = '\0';
+ return wd;
+ }
+}
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