diff options
-rw-r--r-- | src/basic/fileio.c | 11 | ||||
-rw-r--r-- | src/test/test-fileio.c | 12 |
2 files changed, 18 insertions, 5 deletions
diff --git a/src/basic/fileio.c b/src/basic/fileio.c index e69b888315..60a9885108 100644 --- a/src/basic/fileio.c +++ b/src/basic/fileio.c @@ -470,9 +470,14 @@ int read_virtual_file(const char *filename, size_t max_size, char **ret_contents if (n <= size) break; - /* If a maximum size is specified and we already read as much, no need to try again */ - if (max_size != SIZE_MAX && n >= max_size) { - n = max_size; + /* If a maximum size is specified and we already read more we know the file is larger, and + * can handle this as truncation case. Note that if the size of what we read equals the + * maximum size then this doesn't mean truncation, the file might or might not end on that + * byte. We need to rerun the loop in that case, with a larger buffer size, so that we read + * at least one more byte to be able to distinguish EOF from truncation. */ + if (max_size != SIZE_MAX && n > max_size) { + n = size; /* Make sure we never use more than what we sized the buffer for (so that + * we have one free byte in it for the trailing NUL we add below).*/ truncated = true; break; } diff --git a/src/test/test-fileio.c b/src/test/test-fileio.c index 2b6ef495aa..fa8a66df04 100644 --- a/src/test/test-fileio.c +++ b/src/test/test-fileio.c @@ -1047,7 +1047,11 @@ static void test_read_virtual_file(size_t max_size) { FOREACH_STRING(filename, "/proc/1/cmdline", "/etc/nsswitch.conf", - "/sys/kernel/uevent_seqnum") { + "/sys/kernel/uevent_seqnum", + "/proc/kcore", + "/proc/kallsyms", + "/proc/self/exe", + "/proc/self/pagemap") { _cleanup_free_ char *buf = NULL; size_t size = 0; @@ -1055,7 +1059,11 @@ static void test_read_virtual_file(size_t max_size) { r = read_virtual_file(filename, max_size, &buf, &size); if (r < 0) { log_info_errno(r, "read_virtual_file(\"%s\", %zu): %m", filename, max_size); - assert_se(ERRNO_IS_PRIVILEGE(r) || r == -ENOENT); + assert_se(ERRNO_IS_PRIVILEGE(r) || /* /proc/kcore is not accessible to unpriv */ + IN_SET(r, + -ENOENT, /* Some of the files might be absent */ + -EINVAL, /* too small reads from /proc/self/pagemap trigger EINVAL */ + -EFBIG)); /* /proc/kcore and /proc/self/pagemap should be too large */ } else log_info("read_virtual_file(\"%s\", %zu): %s (%zu bytes)", filename, max_size, r ? "non-truncated" : "truncated", size); } |