utils: improve switch_to_ns()

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This commit is contained in:
Christian Brauner 2019-03-12 17:51:50 +01:00
parent c6494c4b88
commit b280bc380c
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GPG Key ID: 8EB056D53EECB12D
2 changed files with 11 additions and 8 deletions

View File

@ -149,6 +149,7 @@
#define LXC_LINELEN 4096
#define LXC_IDMAPLEN 4096
#define LXC_MAX_BUFFER 4096
#define LXC_NAMESPACE_NAME_MAX 256
/* /proc/ = 6
* +

View File

@ -693,15 +693,18 @@ int detect_shared_rootfs(void)
bool switch_to_ns(pid_t pid, const char *ns)
{
int fd, ret;
char nspath[PATH_MAX];
__do_close_prot_errno int fd = -EBADF;
int ret;
char nspath[STRLITERALLEN("/proc//ns/")
+ INTTYPE_TO_STRLEN(pid_t)
+ LXC_NAMESPACE_NAME_MAX];
/* Switch to new ns */
ret = snprintf(nspath, PATH_MAX, "/proc/%d/ns/%s", pid, ns);
if (ret < 0 || ret >= PATH_MAX)
ret = snprintf(nspath, sizeof(nspath), "/proc/%d/ns/%s", pid, ns);
if (ret < 0 || ret >= sizeof(nspath))
return false;
fd = open(nspath, O_RDONLY);
fd = open(nspath, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
SYSERROR("Failed to open \"%s\"", nspath);
return false;
@ -709,12 +712,11 @@ bool switch_to_ns(pid_t pid, const char *ns)
ret = setns(fd, 0);
if (ret) {
SYSERROR("Failed to set process %d to \"%s\" of %d.", pid, ns, fd);
close(fd);
SYSERROR("Failed to set process %d to \"%s\" of %d.", pid, ns,
fd);
return false;
}
close(fd);
return true;
}