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-rw-r--r--util/symlinks.c391
1 files changed, 391 insertions, 0 deletions
diff --git a/util/symlinks.c b/util/symlinks.c
new file mode 100644
index 0000000..e9d2b01
--- /dev/null
+++ b/util/symlinks.c
@@ -0,0 +1,391 @@
+#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 occurrence 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);
+}
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