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Introduce loop_read_exact helper 

Usually when using loop_read(), we want to read the full buffer.
Add a helper that mirrors loop_write(), and returns 0 when full buffer
was read, and an error otherwise.

Use -ENODATA for the short read, to distinguish it from a read error.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2015-03-09 21:23:53 -04:00
parent ad7bcf526d
commit a6dcc7e592
8 changed files with 52 additions and 66 deletions
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10
src/core/automount.c
View File

@ -725,7 +725,6 @@ static bool automount_check_gc(Unit *u) {
static int automount_dispatch_io(sd_event_source *s, int fd, uint32_t events, void *userdata) {
union autofs_v5_packet_union packet;
Automount *a = AUTOMOUNT(userdata);
ssize_t l;
int r;
assert(a);
@ -736,12 +735,9 @@ static int automount_dispatch_io(sd_event_source *s, int fd, uint32_t events, vo
goto fail;
}
l = loop_read(a->pipe_fd, &packet, sizeof(packet), true);
if (l != sizeof(packet)) {
if (l < 0)
log_unit_error_errno(UNIT(a)->id, l, "Invalid read from pipe: %m");
else
log_unit_error(UNIT(a)->id, "Invalid read from pipe: short read");
r = loop_read_exact(a->pipe_fd, &packet, sizeof(packet), true);
if (r < 0) {
log_unit_error_errno(UNIT(a)->id, r, "Invalid read from pipe: %m");
goto fail;
}

15
src/core/machine-id-setup.c
View File

@ -64,7 +64,6 @@ static int generate(char id[34], const char *root) {
unsigned char *p;
sd_id128_t buf;
char *q;
ssize_t k;
const char *vm_id, *dbus_machine_id;
assert(id);
@ -77,11 +76,10 @@ static int generate(char id[34], const char *root) {
/* First, try reading the D-Bus machine id, unless it is a symlink */
fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd >= 0) {
k = loop_read(fd, id, 33, false);
r = loop_read_exact(fd, id, 33, false);
safe_close(fd);
if (k == 33 && id[32] == '\n') {
if (r >= 0 && id[32] == '\n') {
id[32] = 0;
if (id128_is_valid(id)) {
id[32] = '\n';
@ -119,14 +117,14 @@ static int generate(char id[34], const char *root) {
r = detect_vm(&vm_id);
if (r > 0 && streq(vm_id, "kvm")) {
char uuid[37];
char uuid[36];
fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd >= 0) {
k = loop_read(fd, uuid, 36, false);
r = loop_read_exact(fd, uuid, 36, false);
safe_close(fd);
if (k >= 36) {
if (r >= 0) {
r = shorten_uuid(id, uuid);
if (r >= 0) {
log_info("Initializing machine ID from KVM UUID.");
@ -162,7 +160,8 @@ static int get_valid_machine_id(int fd, char id[34]) {
assert(fd >= 0);
assert(id);
if (loop_read(fd, id_to_validate, 33, false) == 33 && id_to_validate[32] == '\n') {
if (loop_read_exact(fd, id_to_validate, 33, false) >= 0 &&
id_to_validate[32] == '\n') {
id_to_validate[32] = 0;
if (id128_is_valid(id_to_validate)) {

25
src/journal/compress.c
View File

@ -589,14 +589,12 @@ int decompress_stream_lz4(int fdf, int fdt, off_t max_bytes) {
return log_oom();
for (;;) {
ssize_t n, m;
ssize_t m;
int r;
n = read(fdf, &header, sizeof(header));
if (n < 0)
return -errno;
if (n != sizeof(header))
return errno ? -errno : -EIO;
r = loop_read_exact(fdf, &header, sizeof(header), false);
if (r < 0)
return r;
m = le32toh(header);
if (m == 0)
@ -618,12 +616,9 @@ int decompress_stream_lz4(int fdf, int fdt, off_t max_bytes) {
if (!GREEDY_REALLOC(buf, buf_size, m))
return log_oom();
errno = 0;
n = loop_read(fdf, buf, m, false);
if (n < 0)
return n;
if (n != m)
return errno ? -errno : -EIO;
r = loop_read_exact(fdf, buf, m, false);
if (r < 0)
return r;
r = LZ4_decompress_safe_continue(&lz4_data, buf, out, m, 4*LZ4_BUFSIZE);
if (r <= 0)
@ -636,9 +631,9 @@ int decompress_stream_lz4(int fdf, int fdt, off_t max_bytes) {
return -EFBIG;
}
n = loop_write(fdt, out, r, false);
if (n < 0)
return n;
r = loop_write(fdt, out, r, false);
if (r < 0)
return r;
}
log_debug("LZ4 decompression finished (%zu -> %zu bytes, %.1f%%)",

8
src/journal/journalctl.c
View File

@ -1286,7 +1286,6 @@ static int setup_keys(void) {
#ifdef HAVE_GCRYPT
size_t mpk_size, seed_size, state_size, i;
uint8_t *mpk, *seed, *state;
ssize_t l;
int fd = -1, r;
sd_id128_t machine, boot;
char *p = NULL, *k = NULL;
@ -1351,10 +1350,9 @@ static int setup_keys(void) {
}
log_info("Generating seed...");
l = loop_read(fd, seed, seed_size, true);
if (l < 0 || (size_t) l != seed_size) {
log_error_errno(EIO, "Failed to read random seed: %m");
r = -EIO;
r = loop_read_exact(fd, seed, seed_size, true);
if (r < 0) {
log_error_errno(r, "Failed to read random seed: %m");
goto finish;
}

27
src/libsystemd/sd-id128/sd-id128.c
View File

@ -108,9 +108,9 @@ _public_ int sd_id128_get_machine(sd_id128_t *ret) {
static thread_local bool saved_machine_id_valid = false;
_cleanup_close_ int fd = -1;
char buf[33];
ssize_t k;
unsigned j;
sd_id128_t t;
int r;
assert_return(ret, -EINVAL);
@ -123,13 +123,9 @@ _public_ int sd_id128_get_machine(sd_id128_t *ret) {
if (fd < 0)
return -errno;
k = loop_read(fd, buf, 33, false);
if (k < 0)
return (int) k;
if (k != 33)
return -EIO;
r = loop_read_exact(fd, buf, 33, false);
if (r < 0)
return r;
if (buf[32] !='\n')
return -EIO;
@ -157,10 +153,10 @@ _public_ int sd_id128_get_boot(sd_id128_t *ret) {
static thread_local bool saved_boot_id_valid = false;
_cleanup_close_ int fd = -1;
char buf[36];
ssize_t k;
unsigned j;
sd_id128_t t;
char *p;
int r;
assert_return(ret, -EINVAL);
@ -173,22 +169,19 @@ _public_ int sd_id128_get_boot(sd_id128_t *ret) {
if (fd < 0)
return -errno;
k = loop_read(fd, buf, 36, false);
if (k < 0)
return (int) k;
if (k != 36)
return -EIO;
r = loop_read_exact(fd, buf, 36, false);
if (r < 0)
return r;
for (j = 0, p = buf; j < 16; j++) {
int a, b;
if (p >= buf + k - 1)
if (p >= buf + 35)
return -EIO;
if (*p == '-') {
p++;
if (p >= buf + k - 1)
if (p >= buf + 35)
return -EIO;
}

4
src/shared/logs-show.c
View File

@ -1163,9 +1163,9 @@ static int get_boot_id_for_machine(const char *machine, sd_id128_t *boot_id) {
if (fd < 0)
_exit(EXIT_FAILURE);
k = loop_read(fd, buf, 36, false);
r = loop_read_exact(fd, buf, 36, false);
safe_close(fd);
if (k != 36)
if (k < 0)
_exit(EXIT_FAILURE);
k = send(pair[1], buf, 36, MSG_NOSIGNAL);

28
src/shared/util.c
View File

@ -2326,6 +2326,17 @@ ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
return n;
}
int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll) {
ssize_t n;
n = loop_read(fd, buf, nbytes, do_poll);
if (n < 0)
return n;
if ((size_t) n != nbytes)
return -EIO;
return 0;
}
int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
const uint8_t *p = buf;
@ -2580,8 +2591,9 @@ char* dirname_malloc(const char *path) {
int dev_urandom(void *p, size_t n) {
static int have_syscall = -1;
int r, fd;
ssize_t k;
_cleanup_close_ fd = -1;
int r;
/* Gathers some randomness from the kernel. This call will
* never block, and will always return some data from the
@ -2616,22 +2628,14 @@ int dev_urandom(void *p, size_t n) {
return -errno;
} else
/* too short read? */
return -EIO;
return -ENODATA;
}
fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0)
return errno == ENOENT ? -ENOSYS : -errno;
k = loop_read(fd, p, n, true);
safe_close(fd);
if (k < 0)
return (int) k;
if ((size_t) k != n)
return -EIO;
return 0;
return loop_read_exact(fd, p, n, true);
}
void initialize_srand(void) {

1
src/shared/util.h
View File

@ -432,6 +432,7 @@ int sigaction_many(const struct sigaction *sa, ...);
int fopen_temporary(const char *path, FILE **_f, char **_temp_path);
ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll);
int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll);
int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll);
bool is_device_path(const char *path);