Patch from Jim Gleason <jimg@lineo.com> to fix tar so it no longer breaks hard

links, and no longer segfault in a certain wierd case.

5 files changed, 192 insertions, 10 deletions

diff --git a/Changelog b/Changelog
index 83ca4ad87..90212119f 100644
--- a/Changelog
+++ b/Changelog
@@ -43,6 +43,8 @@
         * Larry Doolittle -- \r handled now in echo and tr
         * Matt Kraai -- rewrite of uniq
         * Mark Whitley -- remix of xargs
+        * Jim Gleason <jimg@lineo.com> -- fixed tar so it no longer breaks 
+            hard links.
 
 
          -Erik Andersen
diff --git a/applets/usage.c b/applets/usage.c
index bd2321fbc..35d69df42 100644
--- a/applets/usage.c
+++ b/applets/usage.c
@@ -1222,8 +1222,7 @@ const char tar_usage[] =
 #endif
         "[-f tarFile] [FILE(s)] ...\n"
 #ifndef BB_FEATURE_TRIVIAL_HELP
-        "\nCreate, extract, or list files from a tar file.  Note that\n"
-        "this version of tar treats hard links as separate files.\n\n"
+        "\nCreate, extract, or list files from a tar file.\n\n"
         "Main operation mode:\n"
 #ifdef BB_FEATURE_TAR_CREATE
         "\tc\t\tcreate\n"
diff --git a/archival/tar.c b/archival/tar.c
index 7e56fb99a..906fd7eda 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -769,6 +769,21 @@ endgame:
 
 #ifdef BB_FEATURE_TAR_CREATE
 
+/*
+** writeTarFile(),  writeFileToTarball(), and writeTarHeader() are
+** the only functions that deal with the HardLinkInfo structure.
+** Even these functions use the xxxHardLinkInfo() functions.
+*/
+typedef struct HardLinkInfo HardLinkInfo;
+struct HardLinkInfo
+{
+        HardLinkInfo *next;           /* Next entry in list */
+        dev_t dev;                    /* Device number */
+        ino_t ino;                    /* Inode number */
+        short linkCount;              /* (Hard) Link Count */
+        char name[1];                 /* Start of filename (must be last) */
+};
+
 /* Some info to be carried along when creating a new tarball */
 struct TarBallInfo
 {
@@ -781,10 +796,62 @@ struct TarBallInfo
                                                                          to include the tarball into itself */
         int verboseFlag;              /* Whether to print extra stuff or not */
         char** excludeList;           /* List of files to not include */
+        HardLinkInfo *hlInfoHead;     /* Hard Link Tracking Information */
+        HardLinkInfo *hlInfo;         /* Hard Link Info for the current file */
 };
 typedef struct TarBallInfo TarBallInfo;
 
 
+/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
+static void
+addHardLinkInfo (HardLinkInfo **hlInfoHeadPtr, dev_t dev, ino_t ino,
+                short linkCount, const char *name)
+{
+        /* Note: hlInfoHeadPtr can never be NULL! */
+        HardLinkInfo *hlInfo;
+
+        hlInfo = (HardLinkInfo *)xmalloc(sizeof(HardLinkInfo)+strlen(name)+1);
+        if (hlInfo) {
+                hlInfo->next = *hlInfoHeadPtr;
+                *hlInfoHeadPtr = hlInfo;
+                hlInfo->dev = dev;
+                hlInfo->ino = ino;
+                hlInfo->linkCount = linkCount;
+                strcpy(hlInfo->name, name);
+        }
+        return;
+}
+
+static void
+freeHardLinkInfo (HardLinkInfo **hlInfoHeadPtr)
+{
+        HardLinkInfo *hlInfo = NULL;
+        HardLinkInfo *hlInfoNext = NULL;
+
+        if (hlInfoHeadPtr) {
+                hlInfo = *hlInfoHeadPtr;
+                while (hlInfo) {
+                        hlInfoNext = hlInfo->next;
+                        free(hlInfo);
+                        hlInfo = hlInfoNext;
+                }
+                *hlInfoHeadPtr = NULL;
+        }
+        return;
+}
+
+/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
+static HardLinkInfo *
+findHardLinkInfo (HardLinkInfo *hlInfo, dev_t dev, ino_t ino)
+{
+        while(hlInfo) {
+                if ((ino == hlInfo->ino) && (dev == hlInfo->dev))
+                        break;
+                hlInfo = hlInfo->next;
+        }
+        return(hlInfo);
+}
+
 /* Put an octal string into the specified buffer.
  * The number is zero and space padded and possibly null padded.
  * Returns TRUE if successful.  */ 
@@ -879,8 +946,11 @@ writeTarHeader(struct TarBallInfo *tbInfo, const char *fileName, struct stat *st
         if (! *header.uname)
                 strcpy(header.uname, "root");
 
-        /* WARNING/NOTICE: I break Hard Links */
-        if (S_ISLNK(statbuf->st_mode)) {
+        if (tbInfo->hlInfo) {
+                /* This is a hard link */
+                header.typeflag = LNKTYPE;
+                strncpy(header.linkname, tbInfo->hlInfo->name, sizeof(header.linkname));
+        } else if (S_ISLNK(statbuf->st_mode)) {
                 int link_size=0;
                 char buffer[BUFSIZ];
                 header.typeflag  = SYMTYPE;
@@ -948,6 +1018,22 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf, void*
 {
         struct TarBallInfo *tbInfo = (struct TarBallInfo *)userData;
 
+        /*
+        ** Check to see if we are dealing with a hard link.
+        ** If so -
+        ** Treat the first occurance of a given dev/inode as a file while
+        ** treating any additional occurances as hard links.  This is done
+        ** by adding the file information to the HardLinkInfo linked list.
+        */
+        tbInfo->hlInfo = NULL;
+        if (statbuf->st_nlink > 1) {
+                tbInfo->hlInfo = findHardLinkInfo(tbInfo->hlInfoHead, statbuf->st_dev, 
+                                statbuf->st_ino);
+                if (tbInfo->hlInfo == NULL)
+                        addHardLinkInfo (&tbInfo->hlInfoHead, statbuf->st_dev,
+                                        statbuf->st_ino, statbuf->st_nlink, fileName);
+        }
+
         /* It is against the rules to archive a socket */
         if (S_ISSOCK(statbuf->st_mode)) {
                 errorMsg("%s: socket ignored\n", fileName);
@@ -973,7 +1059,8 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf, void*
         } 
 
         /* Now, if the file is a regular file, copy it out to the tarball */
-        if (S_ISREG(statbuf->st_mode)) {
+        if ((tbInfo->hlInfo == NULL)
+        &&  (S_ISREG(statbuf->st_mode))) {
                 int  inputFileFd;
                 char buffer[BUFSIZ];
                 ssize_t size=0, readSize=0;
@@ -1015,6 +1102,7 @@ static int writeTarFile(const char* tarName, int verboseFlag, char **argv,
         ssize_t size;
         struct TarBallInfo tbInfo;
         tbInfo.verboseFlag = verboseFlag;
+        tbInfo.hlInfoHead = NULL;
 
         /* Make sure there is at least one file to tar up.  */
         if (*argv == NULL)
@@ -1027,6 +1115,7 @@ static int writeTarFile(const char* tarName, int verboseFlag, char **argv,
                 tbInfo.tarFd = open (tarName, O_WRONLY | O_CREAT | O_TRUNC, 0644);
         if (tbInfo.tarFd < 0) {
                 errorMsg( "Error opening '%s': %s\n", tarName, strerror(errno));
+                freeHardLinkInfo(&tbInfo.hlInfoHead);
                 return ( FALSE);
         }
         tbInfo.excludeList=excludeList;
@@ -1061,8 +1150,10 @@ static int writeTarFile(const char* tarName, int verboseFlag, char **argv,
         close(tarFd);
         if (errorFlag == TRUE) {
                 errorMsg("Error exit delayed from previous errors\n");
+                freeHardLinkInfo(&tbInfo.hlInfoHead);
                 return(FALSE);
         }
+        freeHardLinkInfo(&tbInfo.hlInfoHead);
         return( TRUE);
 }
 
diff --git a/tar.c b/tar.c
index 7e56fb99a..906fd7eda 100644
--- a/tar.c
+++ b/tar.c
@@ -769,6 +769,21 @@ endgame:
 
 #ifdef BB_FEATURE_TAR_CREATE
 
+/*
+** writeTarFile(),  writeFileToTarball(), and writeTarHeader() are
+** the only functions that deal with the HardLinkInfo structure.
+** Even these functions use the xxxHardLinkInfo() functions.
+*/
+typedef struct HardLinkInfo HardLinkInfo;
+struct HardLinkInfo
+{
+        HardLinkInfo *next;           /* Next entry in list */
+        dev_t dev;                    /* Device number */
+        ino_t ino;                    /* Inode number */
+        short linkCount;              /* (Hard) Link Count */
+        char name[1];                 /* Start of filename (must be last) */
+};
+
 /* Some info to be carried along when creating a new tarball */
 struct TarBallInfo
 {
@@ -781,10 +796,62 @@ struct TarBallInfo
                                                                          to include the tarball into itself */
         int verboseFlag;              /* Whether to print extra stuff or not */
         char** excludeList;           /* List of files to not include */
+        HardLinkInfo *hlInfoHead;     /* Hard Link Tracking Information */
+        HardLinkInfo *hlInfo;         /* Hard Link Info for the current file */
 };
 typedef struct TarBallInfo TarBallInfo;
 
 
+/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
+static void
+addHardLinkInfo (HardLinkInfo **hlInfoHeadPtr, dev_t dev, ino_t ino,
+                short linkCount, const char *name)
+{
+        /* Note: hlInfoHeadPtr can never be NULL! */
+        HardLinkInfo *hlInfo;
+
+        hlInfo = (HardLinkInfo *)xmalloc(sizeof(HardLinkInfo)+strlen(name)+1);
+        if (hlInfo) {
+                hlInfo->next = *hlInfoHeadPtr;
+                *hlInfoHeadPtr = hlInfo;
+                hlInfo->dev = dev;
+                hlInfo->ino = ino;
+                hlInfo->linkCount = linkCount;
+                strcpy(hlInfo->name, name);
+        }
+        return;
+}
+
+static void
+freeHardLinkInfo (HardLinkInfo **hlInfoHeadPtr)
+{
+        HardLinkInfo *hlInfo = NULL;
+        HardLinkInfo *hlInfoNext = NULL;
+
+        if (hlInfoHeadPtr) {
+                hlInfo = *hlInfoHeadPtr;
+                while (hlInfo) {
+                        hlInfoNext = hlInfo->next;
+                        free(hlInfo);
+                        hlInfo = hlInfoNext;
+                }
+                *hlInfoHeadPtr = NULL;
+        }
+        return;
+}
+
+/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
+static HardLinkInfo *
+findHardLinkInfo (HardLinkInfo *hlInfo, dev_t dev, ino_t ino)
+{
+        while(hlInfo) {
+                if ((ino == hlInfo->ino) && (dev == hlInfo->dev))
+                        break;
+                hlInfo = hlInfo->next;
+        }
+        return(hlInfo);
+}
+
 /* Put an octal string into the specified buffer.
  * The number is zero and space padded and possibly null padded.
  * Returns TRUE if successful.  */ 
@@ -879,8 +946,11 @@ writeTarHeader(struct TarBallInfo *tbInfo, const char *fileName, struct stat *st
         if (! *header.uname)
                 strcpy(header.uname, "root");
 
-        /* WARNING/NOTICE: I break Hard Links */
-        if (S_ISLNK(statbuf->st_mode)) {
+        if (tbInfo->hlInfo) {
+                /* This is a hard link */
+                header.typeflag = LNKTYPE;
+                strncpy(header.linkname, tbInfo->hlInfo->name, sizeof(header.linkname));
+        } else if (S_ISLNK(statbuf->st_mode)) {
                 int link_size=0;
                 char buffer[BUFSIZ];
                 header.typeflag  = SYMTYPE;
@@ -948,6 +1018,22 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf, void*
 {
         struct TarBallInfo *tbInfo = (struct TarBallInfo *)userData;
 
+        /*
+        ** Check to see if we are dealing with a hard link.
+        ** If so -
+        ** Treat the first occurance of a given dev/inode as a file while
+        ** treating any additional occurances as hard links.  This is done
+        ** by adding the file information to the HardLinkInfo linked list.
+        */
+        tbInfo->hlInfo = NULL;
+        if (statbuf->st_nlink > 1) {
+                tbInfo->hlInfo = findHardLinkInfo(tbInfo->hlInfoHead, statbuf->st_dev, 
+                                statbuf->st_ino);
+                if (tbInfo->hlInfo == NULL)
+                        addHardLinkInfo (&tbInfo->hlInfoHead, statbuf->st_dev,
+                                        statbuf->st_ino, statbuf->st_nlink, fileName);
+        }
+
         /* It is against the rules to archive a socket */
         if (S_ISSOCK(statbuf->st_mode)) {
                 errorMsg("%s: socket ignored\n", fileName);
@@ -973,7 +1059,8 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf, void*
         } 
 
         /* Now, if the file is a regular file, copy it out to the tarball */
-        if (S_ISREG(statbuf->st_mode)) {
+        if ((tbInfo->hlInfo == NULL)
+        &&  (S_ISREG(statbuf->st_mode))) {
                 int  inputFileFd;
                 char buffer[BUFSIZ];
                 ssize_t size=0, readSize=0;
@@ -1015,6 +1102,7 @@ static int writeTarFile(const char* tarName, int verboseFlag, char **argv,
         ssize_t size;
         struct TarBallInfo tbInfo;
         tbInfo.verboseFlag = verboseFlag;
+        tbInfo.hlInfoHead = NULL;
 
         /* Make sure there is at least one file to tar up.  */
         if (*argv == NULL)
@@ -1027,6 +1115,7 @@ static int writeTarFile(const char* tarName, int verboseFlag, char **argv,
                 tbInfo.tarFd = open (tarName, O_WRONLY | O_CREAT | O_TRUNC, 0644);
         if (tbInfo.tarFd < 0) {
                 errorMsg( "Error opening '%s': %s\n", tarName, strerror(errno));
+                freeHardLinkInfo(&tbInfo.hlInfoHead);
                 return ( FALSE);
         }
         tbInfo.excludeList=excludeList;
@@ -1061,8 +1150,10 @@ static int writeTarFile(const char* tarName, int verboseFlag, char **argv,
         close(tarFd);
         if (errorFlag == TRUE) {
                 errorMsg("Error exit delayed from previous errors\n");
+                freeHardLinkInfo(&tbInfo.hlInfoHead);
                 return(FALSE);
         }
+        freeHardLinkInfo(&tbInfo.hlInfoHead);
         return( TRUE);
 }
 
diff --git a/usage.c b/usage.c
index bd2321fbc..35d69df42 100644
--- a/usage.c
+++ b/usage.c
@@ -1222,8 +1222,7 @@ const char tar_usage[] =
 #endif
         "[-f tarFile] [FILE(s)] ...\n"
 #ifndef BB_FEATURE_TRIVIAL_HELP
-        "\nCreate, extract, or list files from a tar file.  Note that\n"
-        "this version of tar treats hard links as separate files.\n\n"
+        "\nCreate, extract, or list files from a tar file.\n\n"
         "Main operation mode:\n"
 #ifdef BB_FEATURE_TAR_CREATE
         "\tc\t\tcreate\n"