Use vfork instead of fork, some more cleanup from Vladimir N. Oleynik

diff --git a/archival/tar.c b/archival/tar.c
index bafb7033cff862163f3ce17c5dc01c60328b4d81..379220291cab0eb814deec112de9e4bcea2c3431 100644 (file)
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -138,24 +138,20 @@ enum TarFileType {
 typedef enum TarFileType TarFileType;
 
 /* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
-static inline void addHardLinkInfo(HardLinkInfo ** hlInfoHeadPtr, dev_t dev,
-                                                                  ino_t ino, short linkCount,
-                                                                  const char *name)
+static inline void addHardLinkInfo(HardLinkInfo ** hlInfoHeadPtr,
+                                       struct stat *statbuf,
+                                       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;
+       hlInfo = (HardLinkInfo *) xmalloc(sizeof(HardLinkInfo) + strlen(name));
+       hlInfo->next = *hlInfoHeadPtr;
+       *hlInfoHeadPtr = hlInfo;
+       hlInfo->dev = statbuf->st_dev;
+       hlInfo->ino = statbuf->st_ino;
+       hlInfo->linkCount = statbuf->st_nlink;
+       strcpy(hlInfo->name, name);
 }
 
 static void freeHardLinkInfo(HardLinkInfo ** hlInfoHeadPtr)
@@ -176,11 +172,10 @@ static void freeHardLinkInfo(HardLinkInfo ** hlInfoHeadPtr)
 }
 
 /* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
-static inline HardLinkInfo *findHardLinkInfo(HardLinkInfo * hlInfo, dev_t dev,
-                                                                                        ino_t ino)
+static inline HardLinkInfo *findHardLinkInfo(HardLinkInfo * hlInfo, struct stat *statbuf)
 {
        while (hlInfo) {
-               if ((ino == hlInfo->ino) && (dev == hlInfo->dev))
+               if ((statbuf->st_ino == hlInfo->ino) && (statbuf->st_dev == hlInfo->dev))
                        break;
                hlInfo = hlInfo->next;
        }
@@ -366,11 +361,9 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
         */
        tbInfo->hlInfo = NULL;
        if (statbuf->st_nlink > 1) {
-               tbInfo->hlInfo = findHardLinkInfo(tbInfo->hlInfoHead, statbuf->st_dev,
-                                                                                 statbuf->st_ino);
+               tbInfo->hlInfo = findHardLinkInfo(tbInfo->hlInfoHead, statbuf);
                if (tbInfo->hlInfo == NULL)
-                       addHardLinkInfo(&tbInfo->hlInfoHead, statbuf->st_dev,
-                                                       statbuf->st_ino, statbuf->st_nlink, fileName);
+                       addHardLinkInfo(&tbInfo->hlInfoHead, statbuf, fileName);
        }
 
        /* It is against the rules to archive a socket */
@@ -460,6 +453,7 @@ static inline int writeTarFile(const char *tarName, const int verboseFlag,
        int gzipDataPipe[2] = { -1, -1 };
        int gzipStatusPipe[2] = { -1, -1 };
        pid_t gzipPid = 0;
+       volatile int vfork_exec_errno = 0;
 #endif
 
        int errorFlag = FALSE;
@@ -495,13 +489,19 @@ static inline int writeTarFile(const char *tarName, const int verboseFlag,
 
 #ifdef CONFIG_FEATURE_TAR_GZIP
        if (gzip) {
-               if (socketpair(AF_UNIX, SOCK_STREAM, 0, gzipDataPipe) < 0
-                       || pipe(gzipStatusPipe) < 0)
+               if (pipe(gzipDataPipe) < 0 || pipe(gzipStatusPipe) < 0) {
                        perror_msg_and_die("Failed to create gzip pipe");
+               }
 
                signal(SIGPIPE, SIG_IGN);       /* we only want EPIPE on errors */
 
-               gzipPid = fork();
+# if __GNUC__
+                       /* Avoid vfork clobbering */
+                       (void) &include;
+                       (void) &errorFlag;
+# endif
+ 
+               gzipPid = vfork();
 
                if (gzipPid == 0) {
                        dup2(gzipDataPipe[0], 0);
@@ -514,10 +514,9 @@ static inline int writeTarFile(const char *tarName, const int verboseFlag,
                        fcntl(gzipStatusPipe[1], F_SETFD, FD_CLOEXEC);  /* close on exec shows sucess */
 
                        execl("/bin/gzip", "gzip", "-f", 0);
+                       vfork_exec_errno = errno;
 
-                       write(gzipStatusPipe[1], "", 1);
                        close(gzipStatusPipe[1]);
-
                        exit(-1);
                } else if (gzipPid > 0) {
                        close(gzipDataPipe[0]);
@@ -528,9 +527,10 @@ static inline int writeTarFile(const char *tarName, const int verboseFlag,
 
                                int n = read(gzipStatusPipe[0], &buf, 1);
 
-                               if (n == 1)
-                                       error_msg_and_die("Could not exec gzip process");       /* socket was not closed => error */
-                               else if ((n < 0) && (errno == EAGAIN || errno == EINTR))
+                               if (n == 0 && vfork_exec_errno != 0) {
+                                       errno = vfork_exec_errno;
+                                       perror_msg_and_die("Could not exec gzip process");
+                               } else if ((n < 0) && (errno == EAGAIN || errno == EINTR))
                                        continue;       /* try it again */
                                break;
                        }
@@ -538,7 +538,7 @@ static inline int writeTarFile(const char *tarName, const int verboseFlag,
 
                        tbInfo.tarFd = gzipDataPipe[1];
                } else {
-                       perror_msg_and_die("Failed to fork gzip process");
+                       perror_msg_and_die("Failed to vfork gzip process");
                }
        }
 #endif
@@ -603,7 +603,7 @@ int tar_main(int argc, char **argv)
        archive_handle_t *tar_handle;
        int opt;
        char *base_dir = NULL;
-       char *tar_filename = "-";
+       const char *tar_filename = "-";
 
 #ifdef CONFIG_FEATURE_TAR_CREATE
        unsigned char tar_create = FALSE;