rename: add --symlink option for renaming symlink target

[kzak@redhat.com: - coding style clean up]

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 51 insertions, 13 deletions

diff --git a/misc-utils/rename.c b/misc-utils/rename.c
index b17e03bb1..35c69b714 100644
--- a/misc-utils/rename.c
+++ b/misc-utils/rename.c
@@ -18,27 +18,51 @@ for i in $@; do N=`echo "$i" | sed "s/$FROM/$TO/g"`; mv "$i" "$N"; done
 #include <stdlib.h>
 #include <errno.h>
 #include <getopt.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #include "nls.h"
 #include "xalloc.h"
 #include "c.h"
 #include "closestream.h"
 
-static int do_rename(char *from, char *to, char *s, int verbose)
+static int do_rename(char *from, char *to, char *s, int verbose, int symtarget)
 {
-	char *newname, *where, *p, *q;
+	char *newname, *where, *p, *q, *target;
 	int flen, tlen, slen;
+	struct stat sb;
+
+	if (symtarget) {
+		if (lstat(s, &sb) == -1)
+			err(EXIT_FAILURE, _("%s: lstat failed"), s);
+
+		if (!S_ISLNK(sb.st_mode))
+			errx(EXIT_FAILURE, _("%s: not a symbolic link"), s);
+
+		target = xmalloc(sb.st_size + 1);
+		if (readlink(s, target, sb.st_size + 1) < 0)
+			err(EXIT_FAILURE, _("%s: readlink failed"), s);
+
+		target[sb.st_size] = '\0';
+		where = strstr(target, from);
+	} else
+		where = strstr(s, from);
 
-	where = strstr(s, from);
 	if (where == NULL)
 		return 0;
 
 	flen = strlen(from);
 	tlen = strlen(to);
-	slen = strlen(s);
+	if (symtarget) {
+		slen = strlen(target);
+		p = target;
+	} else {
+		slen = strlen(s);
+		p = s;
+	}
 	newname = xmalloc(tlen + slen + 1);
 
-	p = s;
 	q = newname;
 	while (p < where)
 		*q++ = *p++;
@@ -50,11 +74,20 @@ static int do_rename(char *from, char *to, char *s, int verbose)
 		*q++ = *p++;
 	*q = 0;
 
-	if (rename(s, newname) != 0)
-		err(EXIT_FAILURE, _("renaming %s to %s failed"),
-		    s, newname);
-	if (verbose)
-		printf("`%s' -> `%s'\n", s, newname);
+	if (symtarget) {
+		if (0 > unlink(s))
+			err(EXIT_FAILURE, _("%s: unlink failed"), s);
+		if (symlink(newname, s) != 0)
+			err(EXIT_FAILURE, _("%s: symlinking to %s failed"), s, newname);
+		if (verbose)
+			printf("%s: `%s' -> `%s'\n", s, target, newname);
+	} else {
+		if (rename(s, newname) != 0)
+			err(EXIT_FAILURE, _("%s: rename to %s failed"), s, newname);
+		if (verbose)
+			printf("`%s' -> `%s'\n", s, newname);
+	}
+
 
 	free(newname);
 	return 1;
@@ -70,6 +103,7 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
 	fputs(_("\nOptions:\n"), out);
 	fputs(_(" -v, --verbose    explain what is being done\n"
 		" -V, --version    output version information and exit\n"
+		" -s, --symlink    act on symlink target\n"
 		" -h, --help       display this help and exit\n\n"), out);
 
 	exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
@@ -78,12 +112,13 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
 int main(int argc, char **argv)
 {
 	char *from, *to;
-	int i, c, verbose = 0;
+	int i, c, symtarget=0, verbose = 0;
 
 	static const struct option longopts[] = {
 		{"verbose", no_argument, NULL, 'v'},
 		{"version", no_argument, NULL, 'V'},
 		{"help", no_argument, NULL, 'h'},
+		{"symlink", no_argument, NULL, 's'},
 		{NULL, 0, NULL, 0}
 	};
 
@@ -92,11 +127,14 @@ int main(int argc, char **argv)
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((c = getopt_long(argc, argv, "vVh", longopts, NULL)) != -1)
+	while ((c = getopt_long(argc, argv, "vsVh", longopts, NULL)) != -1)
 		switch (c) {
 		case 'v':
 			verbose = 1;
 			break;
+		case 's':
+			symtarget = 1;
+			break;
 		case 'V':
 			printf(_("%s from %s\n"),
 			       program_invocation_short_name,
@@ -120,7 +158,7 @@ int main(int argc, char **argv)
 	to = argv[1];
 
 	for (i = 2; i < argc; i++)
-		do_rename(from, to, argv[i], verbose);
+		do_rename(from, to, argv[i], verbose, symtarget);
 
 	return EXIT_SUCCESS;
 }