Diff of /tags/mkinitrd-6_2_0/libbb/xreadlink.c

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	revision 532 by niro, Sat Sep 1 22:45:15 2007 UTC	revision 816 by niro, Fri Apr 24 18:33:46 2009 UTC
#	Line 8	Line 8
8
9	/*	/*
10	* NOTE: This function returns a malloced char* that you will have to free	* NOTE: This function returns a malloced char* that you will have to free
11	* yourself. You have been warned.	* yourself.
12	*/	*/
13		char* FAST_FUNC xmalloc_readlink(const char *path)
	char *xreadlink(const char *path)
14	{	{
15	enum { GROWBY = 80 }; /* how large we will grow strings by */	enum { GROWBY = 80 }; /* how large we will grow strings by */
16
#	Line 19  char *xreadlink(const char *path)	Line 18  char *xreadlink(const char *path)
18	int bufsize = 0, readsize = 0;	int bufsize = 0, readsize = 0;
19
20	do {	do {
21	buf = xrealloc(buf, bufsize += GROWBY);	bufsize += GROWBY;
22	readsize = readlink(path, buf, bufsize); /* 1st try */	buf = xrealloc(buf, bufsize);
23		readsize = readlink(path, buf, bufsize);
24	if (readsize == -1) {	if (readsize == -1) {
	bb_perror_msg("%s", path);
25	free(buf);	free(buf);
26	return NULL;	return NULL;
27	}	}
28	}	} while (bufsize < readsize + 1);
	while (bufsize < readsize + 1);
29
30	buf[readsize] = '\0';	buf[readsize] = '\0';
31
32	return buf;	return buf;
33	}	}
34
35	char *xmalloc_realpath(const char *path)	/*
36		* This routine is not the same as realpath(), which
37		* canonicalizes the given path completely. This routine only
38		* follows trailing symlinks until a real file is reached and
39		* returns its name. If the path ends in a dangling link or if
40		* the target doesn't exist, the path is returned in any case.
41		* Intermediate symlinks in the path are not expanded -- only
42		* those at the tail.
43		* A malloced char* is returned, which must be freed by the caller.
44		*/
45		char* FAST_FUNC xmalloc_follow_symlinks(const char *path)
46		{
47		char *buf;
48		char *lpc;
49		char *linkpath;
50		int bufsize;
51		int looping = MAXSYMLINKS + 1;
52
53		buf = xstrdup(path);
54		goto jump_in;
55
56		while (1) {
57		linkpath = xmalloc_readlink(buf);
58		if (!linkpath) {
59		/* not a symlink, or doesn't exist */
60		if (errno == EINVAL || errno == ENOENT)
61		return buf;
62		goto free_buf_ret_null;
63		}
64
65		if (!--looping) {
66		free(linkpath);
67		free_buf_ret_null:
68		free(buf);
69		return NULL;
70		}
71
72		if (*linkpath != '/') {
73		bufsize += strlen(linkpath);
74		buf = xrealloc(buf, bufsize);
75		lpc = bb_get_last_path_component_strip(buf);
76		strcpy(lpc, linkpath);
77		free(linkpath);
78		} else {
79		free(buf);
80		buf = linkpath;
81		jump_in:
82		bufsize = strlen(buf) + 1;
83		}
84		}
85		}
86
87		char* FAST_FUNC xmalloc_readlink_or_warn(const char *path)
88		{
89		char *buf = xmalloc_readlink(path);
90		if (!buf) {
91		/* EINVAL => "file: Invalid argument" => puzzled user */
92		bb_error_msg("%s: cannot read link (not a symlink?)", path);
93		}
94		return buf;
95		}
96
97		/* UNUSED */
98		#if 0
99		char* FAST_FUNC xmalloc_realpath(const char *path)
100	{	{
101	#if defined(__GLIBC__) && !defined(__UCLIBC__)	#if defined(__GLIBC__) && !defined(__UCLIBC__)
102	/* glibc provides a non-standard extension */	/* glibc provides a non-standard extension */
#	Line 46  char *xmalloc_realpath(const char *path)	Line 108  char *xmalloc_realpath(const char *path)
108	return xstrdup(realpath(path, buf));	return xstrdup(realpath(path, buf));
109	#endif	#endif
110	}	}
111		#endif

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Legend: Removed from v.532   changed lines   Added in v.816