From: Eric Andersen <andersen@codepoet.org>
Date: Mon, 7 May 2001 17:48:28 +0000 (-0000)
Subject: Per some comments from Lars Kellogg-Stedman <lars@larsshack.org>,
X-Git-Tag: 0_52~228
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=28355a36da6ad4d1b55ba9bb146fb0b6586e7edb;p=oweals%2Fbusybox.git

Per some comments from Lars Kellogg-Stedman <lars@larsshack.org>,
make xreadlink() return NULL on failure, and make sure everyone
uses the interface correctly.
 -Erik
---

diff --git a/applets/busybox.c b/applets/busybox.c
index badd53d79..41b6069ed 100644
--- a/applets/busybox.c
+++ b/applets/busybox.c
@@ -37,10 +37,7 @@ typedef int (*__link_f)(const char *, const char *);
  */
 static char *busybox_fullpath()
 {
-	char proc[256];
-
-	sprintf(proc, "/proc/%d/exe", getpid());
-	return xreadlink(proc);
+	return xreadlink("/proc/self/exe");
 }
 
 /* create (sym)links for each applet */
diff --git a/archival/tar.c b/archival/tar.c
index eb085c770..135bfd186 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -922,6 +922,8 @@ writeTarHeader(struct TarBallInfo *tbInfo, const char *header_name,
 		strncpy(header.linkname, tbInfo->hlInfo->name, sizeof(header.linkname));
 	} else if (S_ISLNK(statbuf->st_mode)) {
 		char *lpath = xreadlink(real_name);
+		if (!lpath) /* Already printed err msg inside xreadlink() */
+			return ( FALSE);
 		header.typeflag  = SYMTYPE;
 		strncpy(header.linkname, lpath, sizeof(header.linkname)); 
 		free(lpath);
diff --git a/busybox.c b/busybox.c
index badd53d79..41b6069ed 100644
--- a/busybox.c
+++ b/busybox.c
@@ -37,10 +37,7 @@ typedef int (*__link_f)(const char *, const char *);
  */
 static char *busybox_fullpath()
 {
-	char proc[256];
-
-	sprintf(proc, "/proc/%d/exe", getpid());
-	return xreadlink(proc);
+	return xreadlink("/proc/self/exe");
 }
 
 /* create (sym)links for each applet */
diff --git a/libbb/xreadlink.c b/libbb/xreadlink.c
index 66f63b883..932e487a5 100644
--- a/libbb/xreadlink.c
+++ b/libbb/xreadlink.c
@@ -1,5 +1,6 @@
 /*
- *  xreadlink.c - safe implementation of readlink
+ *  xreadlink.c - safe implementation of readlink.
+ *  Returns a NULL on failure...
  */
 
 #include <stdio.h>
@@ -22,8 +23,10 @@ extern char *xreadlink(const char *path)
 	do {
 		buf = xrealloc(buf, bufsize += GROWBY);
 		readsize = readlink(path, buf, bufsize); /* 1st try */
-		if (readsize == -1)
-			perror_msg("%s:%s", applet_name, path);
+		if (readsize == -1) {
+		    perror_msg("%s:%s", applet_name, path);
+		    return NULL;
+		}
 	}           
 	while (bufsize < readsize + 1);
 
diff --git a/miscutils/readlink.c b/miscutils/readlink.c
index 226649544..c46ebd108 100644
--- a/miscutils/readlink.c
+++ b/miscutils/readlink.c
@@ -37,6 +37,8 @@ int readlink_main(int argc, char **argv)
 		show_usage();
 
 	buf = xreadlink(argv[1]);
+	if (!buf)
+		return EXIT_FAILURE;
 	puts(buf);
 #ifdef BB_FEATURE_CLEAN_UP
 	free(buf);
diff --git a/readlink.c b/readlink.c
index 226649544..c46ebd108 100644
--- a/readlink.c
+++ b/readlink.c
@@ -37,6 +37,8 @@ int readlink_main(int argc, char **argv)
 		show_usage();
 
 	buf = xreadlink(argv[1]);
+	if (!buf)
+		return EXIT_FAILURE;
 	puts(buf);
 #ifdef BB_FEATURE_CLEAN_UP
 	free(buf);
diff --git a/tar.c b/tar.c
index eb085c770..135bfd186 100644
--- a/tar.c
+++ b/tar.c
@@ -922,6 +922,8 @@ writeTarHeader(struct TarBallInfo *tbInfo, const char *header_name,
 		strncpy(header.linkname, tbInfo->hlInfo->name, sizeof(header.linkname));
 	} else if (S_ISLNK(statbuf->st_mode)) {
 		char *lpath = xreadlink(real_name);
+		if (!lpath) /* Already printed err msg inside xreadlink() */
+			return ( FALSE);
 		header.typeflag  = SYMTYPE;
 		strncpy(header.linkname, lpath, sizeof(header.linkname)); 
 		free(lpath);