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basic/uid-range: add uid_map_read_one helper

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This commit is contained in:
Mike Yuan
2023-12-15 21:22:51 +08:00
parent 121b705426
commit 7312c422f0
4 changed files with 54 additions and 50 deletions
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src/basic/virt.c
+9 -12
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@@ -21,6 +21,7 @@
#include "stat-util.h"
#include "string-table.h"
#include "string-util.h"
#include "uid-range.h"
#include "virt.h"
enum {
@@ -814,7 +815,7 @@ Virtualization detect_virtualization(void) {
static int userns_has_mapping(const char *name) {
_cleanup_fclose_ FILE *f = NULL;
uid_t a, b, c;
uid_t base, shift, range;
int r;
f = fopen(name, "re");
@@ -823,26 +824,22 @@ static int userns_has_mapping(const char *name) {
return errno == ENOENT ? false : -errno;
}
errno = 0;
r = fscanf(f, UID_FMT " " UID_FMT " " UID_FMT "\n", &a, &b, &c);
if (r == EOF) {
if (ferror(f))
return log_debug_errno(errno_or_else(EIO), "Failed to read %s: %m", name);
log_debug("%s is empty, we're in an uninitialized user namespace", name);
r = uid_map_read_one(f, &base, &shift, &range);
if (r == -ENOMSG) {
log_debug("%s is empty, we're in an uninitialized user namespace.", name);
return true;
}
if (r != 3)
return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG), "Failed to parse %s: %m", name);
if (r < 0)
return log_debug_errno(r, "Failed to read %s: %m", name);
if (a == 0 && b == 0 && c == UINT32_MAX) {
if (base == 0 && shift == 0 && range == UINT32_MAX) {
/* The kernel calls mappings_overlap() and does not allow overlaps */
log_debug("%s has a full 1:1 mapping", name);
return false;
}
/* Anything else implies that we are in a user namespace */
log_debug("Mapping found in %s, we're in a user namespace", name);
log_debug("Mapping found in %s, we're in a user namespace.", name);
return true;
}