Quoting Christian Brauner (christianvanbrau...@gmail.com):
> Use pwrite() to write terminating \0-byte
>
> This allows us to use standard string handling functions and we can avoid
> using
> the GNU-extension memmem(). This simplifies removing the container from the
> lxc_snapshots file. Wrap strstr() in a while loop to remove duplicate entries.
>
> Signed-off-by: Christian Brauner <christianvanbrau...@gmail.com>
Acked-by: Serge E. Hallyn <serge.hal...@ubuntu.com>
> ---
> src/lxc/lxccontainer.c | 70
> +++++++++++++++++++++++---------------------------
> 1 file changed, 32 insertions(+), 38 deletions(-)
>
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index fb99892..78021b6 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -1983,13 +1983,13 @@ static bool mod_rdep(struct lxc_container *c0, struct
> lxc_container *c, bool inc
> {
> FILE *f1;
> struct stat fbuf;
> - char *buf = NULL;
> - char *del;
> + void *buf = NULL;
> + char *del = NULL;
> char path[MAXPATHLEN];
> char newpath[MAXPATHLEN];
> int fd, ret, n = 0, v = 0;
> bool bret = false;
> - size_t len, difflen;
> + size_t len = 0, bytes = 0;
>
> if (container_disk_lock(c0))
> return false;
> @@ -2049,55 +2049,49 @@ static bool mod_rdep(struct lxc_container *c0, struct
> lxc_container *c, bool inc
> goto out;
> }
> } else if (!inc) {
> - fd = open(path, O_RDWR | O_CLOEXEC);
> - if (fd < 0)
> - goto out;
> -
> - ret = fstat(fd, &fbuf);
> - if (ret < 0) {
> - close(fd);
> - goto out;
> - }
> + if ((fd = open(path, O_RDWR | O_CLOEXEC)) < 0)
> + goto out;
>
> - if (fbuf.st_size != 0) {
> - buf = mmap(NULL, fbuf.st_size, PROT_READ |
> PROT_WRITE, MAP_SHARED, fd, 0);
> - if (buf == MAP_FAILED) {
> - SYSERROR("Failed to create mapping %s",
> path);
> - close(fd);
> - goto out;
> - }
> - }
> + if (fstat(fd, &fbuf) < 0) {
> + close(fd);
> + goto out;
> + }
>
> - len = strlen(newpath);
> + if (fbuf.st_size != 0) {
> + /* write terminating \0-byte to file */
> + if (pwrite(fd, "", 1, fbuf.st_size) <= 0) {
> + close(fd);
> + goto out;
> + }
>
> - /* mmap()ed memory is only \0-terminated when it is not
> - * a multiple of a pagesize. Hence, we'll use memmem().
> */
> - if ((del = memmem(buf, fbuf.st_size, newpath, len)))
> {
> - /* remove container entry */
> - if (del != buf + fbuf.st_size - len) {
> - difflen = fbuf.st_size - (del-buf);
> - memmove(del, del + len, strnlen(del,
> difflen) - len);
> + buf = mmap(NULL, fbuf.st_size + 1, PROT_READ
> | PROT_WRITE, MAP_SHARED, fd, 0);
> + if (buf == MAP_FAILED) {
> + SYSERROR("Failed to create mapping
> %s", path);
> + close(fd);
> + goto out;
> }
>
> - munmap(buf, fbuf.st_size);
> + len = strlen(newpath);
> + while ((del = strstr((char *)buf, newpath)))
> {
> + memmove(del, del + len, strlen(del)
> - len + 1);
> + bytes += len;
> + }
>
> - if (ftruncate(fd, fbuf.st_size - len) < 0) {
> + munmap(buf, fbuf.st_size + 1);
> + if (ftruncate(fd, fbuf.st_size - bytes) < 0)
> {
> SYSERROR("Failed to truncate file
> %s", path);
> close(fd);
> goto out;
> }
> - } else {
> - munmap(buf, fbuf.st_size);
> - }
> -
> - close(fd);
> - }
> + }
> + close(fd);
> + }
>
> /* If the lxc-snapshot file is empty, remove it. */
> if (stat(path, &fbuf) < 0)
> goto out;
> - if (!fbuf.st_size) {
> - remove(path);
> + if (!fbuf.st_size) {
> + remove(path);
> }
> }
>
> --
> 2.5.1
>
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