e2fsprogs/util/symlinks.c - backupdr - Git at Google

 #define _FILE_OFFSET_BITS 64
 #ifndef _LARGEFILE_SOURCE
 #define _LARGEFILE_SOURCE
 #endif
 #ifndef _LARGEFILE64_SOURCE
 #define _LARGEFILE64_SOURCE
 #endif

 #include <unistd.h>
 #ifndef _POSIX_SOURCE
 #define _POSIX_SOURCE
 #endif
 #include <stdio.h>
 #include <stdlib.h>
 #ifdef HAVE_MALLOC_H
 #include <malloc.h>
 #endif
 #include <string.h>
 #include <fcntl.h>
 #include <sys/param.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <dirent.h>
 #include <time.h>
 #include <stddef.h>
 #include <errno.h>

 #ifndef S_ISLNK
 #define S_ISLNK(mode) (((mode) & (_S_IFMT)) == (_S_IFLNK))
 #endif

 #ifndef PATH_MAX
 #define PATH_MAX 1024
 #endif

 #define progver "%s: scan/change symbolic links - v1.3 - by Mark Lord\n\n"
 static char *progname;
 static int verbose = 0, fix_links = 0, recurse = 0, delete = 0, shorten = 0,
 		testing = 0, single_fs = 1;

 /*
  * tidypath removes excess slashes and "." references from a path string
  */

 static int substr (char *s, char *old, char *new)
 {
 	char *tmp = NULL;
 	int oldlen = strlen(old), newlen = 0;

 	if (NULL == strstr(s, old))
 		return 0;

 	if (new)
 		newlen = strlen(new);

 	if (newlen > oldlen) {
 		if ((tmp = malloc(strlen(s))) == NULL) {
 			fprintf(stderr, "no memory\n");
 			exit (1);
 		}
 	}

 	while (NULL != (s = strstr(s, old))) {
 		char *p, *old_s = s;

 		if (new) {
 			if (newlen > oldlen)
 				old_s = strcpy(tmp, s);
 			p = new;
 			while (*p)
 				*s++ = *p++;
 		}
 		p = old_s + oldlen;
 		while ((*s++ = *p++));
 	}
 	if (tmp)
 		free(tmp);
 	return 1;
 }


 static int tidy_path (char *path)
 {
 	int tidied = 0;
 	char *s, *p;

 	s = path + strlen(path) - 1;
 	if (s[0] != '/') {	/* tmp trailing slash simplifies things */
 		s[1] = '/';
 		s[2] = '\0';
 	}
 	while (substr(path, "/./", "/"))
 		tidied = 1;
 	while (substr(path, "//", "/"))
 		tidied = 1;

 	while ((p = strstr(path,"/../")) != NULL) {
 		s = p+3;
 		for (p--; p != path; p--) if (*p == '/') break;
 		if (*p != '/')
 			break;
 		while ((*p++ = *s++));
 		tidied = 1;
 	}
 	if (*path == '\0')
 		strcpy(path,"/");
 	p = path + strlen(path) - 1;
 	if (p != path && *p == '/')
 		*p-- = '\0';	/* remove tmp trailing slash */
 	while (p != path && *p == '/') {	/* remove any others */
 		*p-- = '\0';
 		tidied = 1;
 	}
 	while (!strncmp(path,"./",2)) {
 		for (p = path, s = path+2; (*p++ = *s++););
 		tidied = 1;
 	}
 	return tidied;
 }

 static int shorten_path (char *path, char *abspath)
 {
 	static char dir[PATH_MAX];
 	int shortened = 0;
 	char *p;

 	/* get rid of unnecessary "../dir" sequences */
 	while (abspath && strlen(abspath) > 1 && (p = strstr(path,"../"))) {
 		/* find innermost occurance of "../dir", and save "dir" */
 		int slashes = 2;
 		char *a, *s, *d = dir;
 		while ((s = strstr(p+3, "../"))) {
 			++slashes;
 			p = s;
 		}
 		s = p+3;
 		*d++ = '/';
 		while (*s && *s != '/')
 			*d++ = *s++;
 		*d++ = '/';
 		*d = '\0';
 		if (!strcmp(dir,"//"))
 			break;
 		/* note: p still points at ../dir */
 		if (*s != '/' || !*++s)
 			break;
 		a = abspath + strlen(abspath) - 1;
 		while (slashes-- > 0) {
 			if (a <= abspath)
 				goto ughh;
 			while (*--a != '/') {
 				if (a <= abspath)
 					goto ughh;
 			}
 		}
 		if (strncmp(dir, a, strlen(dir)))
 			break;
 		while ((*p++ = *s++)); /* delete the ../dir */
 		shortened = 1;
 	}
 ughh:
 	return shortened;
 }


 static void fix_symlink (char *path, dev_t my_dev)
 {
 	static char lpath[PATH_MAX], new[PATH_MAX], abspath[PATH_MAX];
 	char *p, *np, *lp, *tail, *msg;
 	struct stat stbuf, lstbuf;
 	int c, fix_abs = 0, fix_messy = 0, fix_long = 0;

 	if ((c = readlink(path, lpath, sizeof(lpath) - 1)) == -1) {
 		perror(path);
 		return;
 	}
 	lpath[c] = '\0';	/* readlink does not null terminate it */

 	/* construct the absolute address of the link */
 	abspath[0] = '\0';
 	if (lpath[0] != '/') {
 		strcat(abspath,path);
 		c = strlen(abspath);
 		if ((c > 0) && (abspath[c-1] == '/'))
 			abspath[c-1] = '\0'; /* cut trailing / */
 		if ((p = strrchr(abspath,'/')) != NULL)
 			*p = '\0'; /* cut last component */
 		strcat(abspath,"/");
 	}
 	strcat(abspath,lpath);
 	(void) tidy_path(abspath);

 	/* check for various things */
 	if (stat(abspath, &stbuf) == -1) {
 		printf("dangling: %s -> %s\n", path, lpath);
 		if (delete) {
 			if (unlink (path)) {
 				perror(path);
 			} else
 				printf("deleted:  %s -> %s\n", path, lpath);
 		}
 		return;
 	}

 	if (single_fs)
 		lstat(abspath, &lstbuf); /* if the above didn't fail, then this shouldn't */

 	if (single_fs && lstbuf.st_dev != my_dev) {
 		msg = "other_fs:";
 	} else if (lpath[0] == '/') {
 		msg = "absolute:";
 		fix_abs = 1;
 	} else if (verbose) {
 		msg = "relative:";
 	} else
 		msg = NULL;
 	fix_messy = tidy_path(strcpy(new,lpath));
 	if (shorten)
 		fix_long = shorten_path(new, path);
 	if (!fix_abs) {
 		if (fix_messy)
 			msg = "messy:   ";
 		else if (fix_long)
 			msg = "lengthy: ";
 	}
 	if (msg != NULL)
 		printf("%s %s -> %s\n", msg, path, lpath);
 	if (!(fix_links || testing) || !(fix_messy || fix_abs || fix_long))
 		return;

 	if (fix_abs) {
 		/* convert an absolute link to relative: */
 		/* point tail at first part of lpath that differs from path */
 		/* point p    at first part of path  that differs from lpath */
 		(void) tidy_path(lpath);
 		tail = lp = lpath;
 		p = path;
 		while (*p && (*p == *lp)) {
 			if (*lp++ == '/') {
 				tail = lp;
 				while (*++p == '/');
 			}
 		}

 		/* now create new, with "../"s followed by tail */
 		np = new;
 		while (*p) {
 			if (*p++ == '/') {
 				*np++ = '.';
 				*np++ = '.';
 				*np++ = '/';
 				while (*p == '/') ++p;
 			}
 		}
 		strcpy (np, tail);
 		(void) tidy_path(new);
 		if (shorten) (void) shorten_path(new, path);
 	}
 	shorten_path(new,path);
 	if (!testing) {
 		if (unlink (path)) {
 			perror(path);
 			return;
 		}
 		if (symlink(new, path)) {
 			perror(path);
 			return;
 		}
 	}
 	printf("changed:  %s -> %s\n", path, new);
 }

 static void dirwalk (char *path, int pathlen, dev_t dev)
 {
  	char *name;
 	DIR *dfd;
 	static struct stat st;
 	static struct dirent *dp;

 	if ((dfd = opendir(path)) == NULL) {
 		perror(path);
 		return;
 	}

 	name = path + pathlen;
 	if (*(name-1) != '/')
 		*name++ = '/';

 	while ((dp = readdir(dfd)) != NULL ) {
 		strcpy(name, dp->d_name);
                 if (strcmp(name, ".") && strcmp(name,"..")) {
 			if (lstat(path, &st) == -1) {
 				perror(path);
 			} else if (st.st_dev == dev) {
 				if (S_ISLNK(st.st_mode)) {
 					fix_symlink (path, dev);
 				} else if (recurse && S_ISDIR(st.st_mode)) {
 					dirwalk(path, strlen(path), dev);
 				}
 			}
 		}
 	}
 	closedir(dfd);
 	path[pathlen] = '\0';
 }

 static void usage_error (void)
 {
 	fprintf(stderr, progver, progname);
 	fprintf(stderr, "Usage:\t%s [-cdorstv] LINK|DIR ...\n\n", progname);
 	fprintf(stderr, "Flags:"
 		"\t-c == change absolute/messy links to relative\n"
 		"\t-d == delete dangling links\n"
 		"\t-o == warn about links across file systems\n"
 		"\t-r == recurse into subdirs\n"
 		"\t-s == shorten lengthy links (displayed in output only when -c not specified)\n"
 		"\t-t == show what would be done by -c\n"
 		"\t-v == verbose (show all symlinks)\n\n");
 	exit(1);
 }

 int main(int argc, char **argv)
 {
 #if defined (_GNU_SOURCE) && defined (__GLIBC__)
 	static char path[PATH_MAX+2];
 	char* cwd = get_current_dir_name();
 #else
 	static char path[PATH_MAX+2], cwd[PATH_MAX+2];
 #endif
 	int dircount = 0;
 	char c, *p;

 	if  ((progname = (char *) strrchr(*argv, '/')) == NULL)
                 progname = *argv;
         else
                 progname++;

 #if defined (_GNU_SOURCE) && defined (__GLIBC__)
 	if (NULL == cwd) {
 		fprintf(stderr,"get_current_dir_name() failed\n");
 #else
 	if (NULL == getcwd(cwd,PATH_MAX)) {
 		fprintf(stderr,"getcwd() failed\n");
 #endif
 		exit (1);
 	}
 #if defined (_GNU_SOURCE) && defined (__GLIBC__)
 	cwd = realloc(cwd, strlen(cwd)+2);
 	if (cwd == NULL) {
 		fprintf(stderr, "realloc() failed\n");
 		exit (1);
 	}
 #endif
 	if (!*cwd || cwd[strlen(cwd)-1] != '/')
 		strcat(cwd,"/");

 	while (--argc) {
 		p = *++argv;
 		if (*p == '-') {
 			if (*++p == '\0')
 				usage_error();
 			while ((c = *p++)) {
 				     if (c == 'c')	fix_links = 1;
 				else if (c == 'd')	delete    = 1;
 				else if (c == 'o')	single_fs = 0;
 				else if (c == 'r')	recurse   = 1;
 				else if (c == 's')	shorten   = 1;
 				else if (c == 't')	testing   = 1;
 				else if (c == 'v')	verbose   = 1;
 				else			usage_error();
 			}
 		} else {
 			struct stat st;
 			if (*p == '/')
 				*path = '\0';
 			else
 				strcpy(path,cwd);
 			tidy_path(strcat(path, p));
 			if (lstat(path, &st) == -1)
 				perror(path);
 			else if (S_ISLNK(st.st_mode))
 				fix_symlink(path, st.st_dev);
 			else
 				dirwalk(path, strlen(path), st.st_dev);
 			++dircount;
 		}
 	}
 	if (dircount == 0)
 		usage_error();
 	exit (0);
 }
	#define _FILE_OFFSET_BITS 64
	#ifndef _LARGEFILE_SOURCE
	#define _LARGEFILE_SOURCE
	#endif
	#ifndef _LARGEFILE64_SOURCE
	#define _LARGEFILE64_SOURCE
	#endif

	#include <unistd.h>
	#ifndef _POSIX_SOURCE
	#define _POSIX_SOURCE
	#endif
	#include <stdio.h>
	#include <stdlib.h>
	#ifdef HAVE_MALLOC_H
	#include <malloc.h>
	#endif
	#include <string.h>
	#include <fcntl.h>
	#include <sys/param.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <dirent.h>
	#include <time.h>
	#include <stddef.h>
	#include <errno.h>

	#ifndef S_ISLNK
	#define S_ISLNK(mode) (((mode) & (_S_IFMT)) == (_S_IFLNK))
	#endif

	#ifndef PATH_MAX
	#define PATH_MAX 1024
	#endif

	#define progver "%s: scan/change symbolic links - v1.3 - by Mark Lord\n\n"
	static char *progname;
	static int verbose = 0, fix_links = 0, recurse = 0, delete = 0, shorten = 0,
	testing = 0, single_fs = 1;

	/*
	* tidypath removes excess slashes and "." references from a path string
	*/

	static int substr (char s, char old, char *new)
	{
	char *tmp = NULL;
	int oldlen = strlen(old), newlen = 0;

	if (NULL == strstr(s, old))
	return 0;

	if (new)
	newlen = strlen(new);

	if (newlen > oldlen) {
	if ((tmp = malloc(strlen(s))) == NULL) {
	fprintf(stderr, "no memory\n");
	exit (1);
	}
	}

	while (NULL != (s = strstr(s, old))) {
	char p, old_s = s;

	if (new) {
	if (newlen > oldlen)
	old_s = strcpy(tmp, s);
	p = new;
	while (*p)
	s++ = p++;
	}
	p = old_s + oldlen;
	while ((s++ = p++));
	}
	if (tmp)
	free(tmp);
	return 1;
	}


	static int tidy_path (char *path)
	{
	int tidied = 0;
	char s, p;

	s = path + strlen(path) - 1;
	if (s[0] != '/') { /* tmp trailing slash simplifies things */
	s[1] = '/';
	s[2] = '\0';
	}
	while (substr(path, "/./", "/"))
	tidied = 1;
	while (substr(path, "//", "/"))
	tidied = 1;

	while ((p = strstr(path,"/../")) != NULL) {
	s = p+3;
	for (p--; p != path; p--) if (*p == '/') break;
	if (*p != '/')
	break;
	while ((p++ = s++));
	tidied = 1;
	}
	if (*path == '\0')
	strcpy(path,"/");
	p = path + strlen(path) - 1;
	if (p != path && *p == '/')
	p-- = '\0'; / remove tmp trailing slash */
	while (p != path && p == '/') { / remove any others */
	*p-- = '\0';
	tidied = 1;
	}
	while (!strncmp(path,"./",2)) {
	for (p = path, s = path+2; (p++ = s++););
	tidied = 1;
	}
	return tidied;
	}

	static int shorten_path (char path, char abspath)
	{
	static char dir[PATH_MAX];
	int shortened = 0;
	char *p;

	/* get rid of unnecessary "../dir" sequences */
	while (abspath && strlen(abspath) > 1 && (p = strstr(path,"../"))) {
	/* find innermost occurance of "../dir", and save "dir" */
	int slashes = 2;
	char a, s, *d = dir;
	while ((s = strstr(p+3, "../"))) {
	++slashes;
	p = s;
	}
	s = p+3;
	*d++ = '/';
	while (s && s != '/')
	d++ = s++;
	*d++ = '/';
	*d = '\0';
	if (!strcmp(dir,"//"))
	break;
	/* note: p still points at ../dir */
	if (s != '/' \|\| !++s)
	break;
	a = abspath + strlen(abspath) - 1;
	while (slashes-- > 0) {
	if (a <= abspath)
	goto ughh;
	while (*--a != '/') {
	if (a <= abspath)
	goto ughh;
	}
	}
	if (strncmp(dir, a, strlen(dir)))
	break;
	while ((p++ = s++)); /* delete the ../dir */
	shortened = 1;
	}
	ughh:
	return shortened;
	}


	static void fix_symlink (char *path, dev_t my_dev)
	{
	static char lpath[PATH_MAX], new[PATH_MAX], abspath[PATH_MAX];
	char p, np, lp, tail, *msg;
	struct stat stbuf, lstbuf;
	int c, fix_abs = 0, fix_messy = 0, fix_long = 0;

	if ((c = readlink(path, lpath, sizeof(lpath) - 1)) == -1) {
	perror(path);
	return;
	}
	lpath[c] = '\0'; /* readlink does not null terminate it */

	/* construct the absolute address of the link */
	abspath[0] = '\0';
	if (lpath[0] != '/') {
	strcat(abspath,path);
	c = strlen(abspath);
	if ((c > 0) && (abspath[c-1] == '/'))
	abspath[c-1] = '\0'; /* cut trailing / */
	if ((p = strrchr(abspath,'/')) != NULL)
	p = '\0'; / cut last component */
	strcat(abspath,"/");
	}
	strcat(abspath,lpath);
	(void) tidy_path(abspath);

	/* check for various things */
	if (stat(abspath, &stbuf) == -1) {
	printf("dangling: %s -> %s\n", path, lpath);
	if (delete) {
	if (unlink (path)) {
	perror(path);
	} else
	printf("deleted: %s -> %s\n", path, lpath);
	}
	return;
	}

	if (single_fs)
	lstat(abspath, &lstbuf); /* if the above didn't fail, then this shouldn't */

	if (single_fs && lstbuf.st_dev != my_dev) {
	msg = "other_fs:";
	} else if (lpath[0] == '/') {
	msg = "absolute:";
	fix_abs = 1;
	} else if (verbose) {
	msg = "relative:";
	} else
	msg = NULL;
	fix_messy = tidy_path(strcpy(new,lpath));
	if (shorten)
	fix_long = shorten_path(new, path);
	if (!fix_abs) {
	if (fix_messy)
	msg = "messy: ";
	else if (fix_long)
	msg = "lengthy: ";
	}
	if (msg != NULL)
	printf("%s %s -> %s\n", msg, path, lpath);
	if (!(fix_links \|\| testing) \|\| !(fix_messy \|\| fix_abs \|\| fix_long))
	return;

	if (fix_abs) {
	/* convert an absolute link to relative: */
	/* point tail at first part of lpath that differs from path */
	/* point p at first part of path that differs from lpath */
	(void) tidy_path(lpath);
	tail = lp = lpath;
	p = path;
	while (p && (p == *lp)) {
	if (*lp++ == '/') {
	tail = lp;
	while (*++p == '/');
	}
	}

	/* now create new, with "../"s followed by tail */
	np = new;
	while (*p) {
	if (*p++ == '/') {
	*np++ = '.';
	*np++ = '.';
	*np++ = '/';
	while (*p == '/') ++p;
	}
	}
	strcpy (np, tail);
	(void) tidy_path(new);
	if (shorten) (void) shorten_path(new, path);
	}
	shorten_path(new,path);
	if (!testing) {
	if (unlink (path)) {
	perror(path);
	return;
	}
	if (symlink(new, path)) {
	perror(path);
	return;
	}
	}
	printf("changed: %s -> %s\n", path, new);
	}

	static void dirwalk (char *path, int pathlen, dev_t dev)
	{
	char *name;
	DIR *dfd;
	static struct stat st;
	static struct dirent *dp;

	if ((dfd = opendir(path)) == NULL) {
	perror(path);
	return;
	}

	name = path + pathlen;
	if (*(name-1) != '/')
	*name++ = '/';

	while ((dp = readdir(dfd)) != NULL ) {
	strcpy(name, dp->d_name);
	if (strcmp(name, ".") && strcmp(name,"..")) {
	if (lstat(path, &st) == -1) {
	perror(path);
	} else if (st.st_dev == dev) {
	if (S_ISLNK(st.st_mode)) {
	fix_symlink (path, dev);
	} else if (recurse && S_ISDIR(st.st_mode)) {
	dirwalk(path, strlen(path), dev);
	}
	}
	}
	}
	closedir(dfd);
	path[pathlen] = '\0';
	}

	static void usage_error (void)
	{
	fprintf(stderr, progver, progname);
	fprintf(stderr, "Usage:\t%s [-cdorstv] LINK\|DIR ...\n\n", progname);
	fprintf(stderr, "Flags:"
	"\t-c == change absolute/messy links to relative\n"
	"\t-d == delete dangling links\n"
	"\t-o == warn about links across file systems\n"
	"\t-r == recurse into subdirs\n"
	"\t-s == shorten lengthy links (displayed in output only when -c not specified)\n"
	"\t-t == show what would be done by -c\n"
	"\t-v == verbose (show all symlinks)\n\n");
	exit(1);
	}

	int main(int argc, char **argv)
	{
	#if defined (_GNU_SOURCE) && defined (__GLIBC__)
	static char path[PATH_MAX+2];
	char* cwd = get_current_dir_name();
	#else
	static char path[PATH_MAX+2], cwd[PATH_MAX+2];
	#endif
	int dircount = 0;
	char c, *p;

	if ((progname = (char ) strrchr(argv, '/')) == NULL)
	progname = *argv;
	else
	progname++;

	#if defined (_GNU_SOURCE) && defined (__GLIBC__)
	if (NULL == cwd) {
	fprintf(stderr,"get_current_dir_name() failed\n");
	#else
	if (NULL == getcwd(cwd,PATH_MAX)) {
	fprintf(stderr,"getcwd() failed\n");
	#endif
	exit (1);
	}
	#if defined (_GNU_SOURCE) && defined (__GLIBC__)
	cwd = realloc(cwd, strlen(cwd)+2);
	if (cwd == NULL) {
	fprintf(stderr, "realloc() failed\n");
	exit (1);
	}
	#endif
	if (!*cwd \|\| cwd[strlen(cwd)-1] != '/')
	strcat(cwd,"/");

	while (--argc) {
	p = *++argv;
	if (*p == '-') {
	if (*++p == '\0')
	usage_error();
	while ((c = *p++)) {
	if (c == 'c') fix_links = 1;
	else if (c == 'd') delete = 1;
	else if (c == 'o') single_fs = 0;
	else if (c == 'r') recurse = 1;
	else if (c == 's') shorten = 1;
	else if (c == 't') testing = 1;
	else if (c == 'v') verbose = 1;
	else usage_error();
	}
	} else {
	struct stat st;
	if (*p == '/')
	*path = '\0';
	else
	strcpy(path,cwd);
	tidy_path(strcat(path, p));
	if (lstat(path, &st) == -1)
	perror(path);
	else if (S_ISLNK(st.st_mode))
	fix_symlink(path, st.st_dev);
	else
	dirwalk(path, strlen(path), st.st_dev);
	++dircount;
	}
	}
	if (dircount == 0)
	usage_error();
	exit (0);
	}