From 57d7cc602d14c6b50e2826e427a5de124e479f95 Mon Sep 17 00:00:00 2001

From: Daniel P. Berrange <berrange@redhat.com>

Date: Mon, 12 Oct 2009 20:32:33 +0100

Subject: [PATCH] Fix virFileReadLimFD/virFileReadAll to handle EINTR

The fread_file_lim() function uses fread() but never handles

EINTR results, causing unexpected failures when reading QEMU

help arg info. It was unneccessarily using FILE * instead

of plain UNIX file handles, which prevented use of saferead()

* src/util/util.c: Switch fread_file_lim over to use saferead

  instead of fread, remove FILE * use, and rename

(cherry picked from commit 11a36d956cb8a5e439e535bff3e0cfce50a64bca)

Fedora-patch: libvirt-fix-qemu-restore-from-raw2.patch

---

 src/util.c |   45 ++++++++++++---------------------------------

 1 files changed, 12 insertions(+), 33 deletions(-)

diff --git a/src/util.c b/src/util.c

index 1878e33..7bc3a66 100644

--- a/src/util.c

+++ b/src/util.c

@@ -887,7 +887,7 @@ virExec(virConnectPtr conn,

    number of bytes.  If the length of the input is <= max_len, and

    upon error while reading that data, it works just like fread_file.  */

 static char *

-fread_file_lim (FILE *stream, size_t max_len, size_t *length)

+saferead_lim (int fd, size_t max_len, size_t *length)

 {

     char *buf = NULL;

     size_t alloc = 0;

@@ -895,8 +895,8 @@ fread_file_lim (FILE *stream, size_t max_len, size_t *length)

     int save_errno;

     for (;;) {

-        size_t count;

-        size_t requested;

+        int count;

+        int requested;

         if (size + BUFSIZ + 1 > alloc) {

             alloc += alloc / 2;

@@ -912,12 +912,12 @@ fread_file_lim (FILE *stream, size_t max_len, size_t *length)

         /* Ensure that (size + requested <= max_len); */

         requested = MIN (size < max_len ? max_len - size : 0,

                          alloc - size - 1);

-        count = fread (buf + size, 1, requested, stream);

+        count = saferead (fd, buf + size, requested);

         size += count;

         if (count != requested || requested == 0) {

             save_errno = errno;

-            if (ferror (stream))

+            if (count < 0)

                 break;

             buf[size] = '\0';

             *length = size;

@@ -930,12 +930,12 @@ fread_file_lim (FILE *stream, size_t max_len, size_t *length)

     return NULL;

 }

-/* A wrapper around fread_file_lim that maps a failure due to

+/* A wrapper around saferead_lim that maps a failure due to

    exceeding the maximum size limitation to EOVERFLOW.  */

-static int virFileReadLimFP(FILE *fp, int maxlen, char **buf)

+int virFileReadLimFD(int fd, int maxlen, char **buf)

 {

     size_t len;

-    char *s = fread_file_lim (fp, maxlen+1, &len;;

+    char *s = saferead_lim (fd, maxlen+1, &len;;

     if (s == NULL)

         return -1;

     if (len > maxlen || (int)len != len) {

@@ -949,37 +949,16 @@ static int virFileReadLimFP(FILE *fp, int maxlen, char **buf)

     return len;

 }

-/* Like virFileReadLimFP, but use a file descriptor rather than a FILE*.  */

-int virFileReadLimFD(int fd_arg, int maxlen, char **buf)

-{

-    int fd = dup (fd_arg);

-    if (fd >= 0) {

-        FILE *fp = fdopen (fd, "r");

-        if (fp) {

-            int len = virFileReadLimFP (fp, maxlen, buf);

-            int saved_errno = errno;

-            fclose (fp);

-            errno = saved_errno;

-            return len;

-        } else {

-            int saved_errno = errno;

-            close (fd);

-            errno = saved_errno;

-        }

-    }

-    return -1;

-}

-

 int virFileReadAll(const char *path, int maxlen, char **buf)

 {

-    FILE *fh = fopen(path, "r");

-    if (fh == NULL) {

+    int fd = open(path, O_RDONLY);

+    if (fd < 0) {

         virReportSystemError(NULL, errno, _("Failed to open file '%s'"), path);

         return -1;

     }

-    int len = virFileReadLimFP (fh, maxlen, buf);

-    fclose(fh);

+    int len = virFileReadLimFD(fd, maxlen, buf);

+    close(fd);

     if (len < 0) {

         virReportSystemError(NULL, errno, _("Failed to read file '%s'"), path);

         return -1;

-- 

1.6.2.5