[PATCH v1 16/30] lib/efi: Cleanup read/write routines
Geoff Levand
geoff at infradead.org
Wed Jul 25 08:15:42 AEST 2018
Make a new stucture struct efi_data to hold the info that describes
an efi variable. Make a common routine efi_open that opens the efi
variable file. Switch the efi get/set/del routines over to use
efi_open.
Signed-off-by: Geoff Levand <geoff at infradead.org>
---
lib/efi/efivar.c | 201 ++++++++++++++++++++++++++++---------------------------
lib/efi/efivar.h | 15 +++--
2 files changed, 112 insertions(+), 104 deletions(-)
diff --git a/lib/efi/efivar.c b/lib/efi/efivar.c
index 1ac6990..0c4b462 100644
--- a/lib/efi/efivar.c
+++ b/lib/efi/efivar.c
@@ -24,6 +24,7 @@
#include <linux/fs.h>
#include <sys/ioctl.h>
+#include <sys/stat.h>
#include "efivar.h"
#include "log/log.h"
@@ -42,150 +43,150 @@ inline const char *get_efivarfs_path(void)
return efivarfs_path;
}
-int efi_del_variable(void *ctx, const char *guidstr,
- const char *name)
+static int efi_open(const char *name, const char *guidstr, int flags,
+ mode_t mode, char **path)
{
- int fd, flag, errno_value;
- int rc = -1;
- const char *dir;
- char *path;
+ int fd;
+
+ *path = NULL;
+
+ if (!get_efivarfs_path())
+ return -1;
- dir = get_efivarfs_path();
- if (!dir)
+ *path = talloc_asprintf(NULL, "%s%s-%s", get_efivarfs_path(), name, guidstr);
+ if (!*path)
return -1;
- path = talloc_asprintf(ctx, "%s%s-%s", dir, name, guidstr);
- if (!path)
+ flags = flags ? flags : O_RDONLY | O_NONBLOCK;
+
+ fd = open(*path, flags, mode);
+
+ if (fd < 0) {
+ pb_log("%s: open failed %s: %s\n", __func__, *path,
+ strerror(errno));
+ talloc_free(*path);
+ *path = NULL;
return -1;
+ }
+
+ return fd;
+}
- fd = open(path, O_RDONLY|O_NONBLOCK);
- if (fd == -1)
- goto err;
+int efi_del_variable(const char *guidstr, const char *name)
+{
+ int fd, flag;
+ int rc = -1;
+ char *path;
+
+ fd = efi_open(name, guidstr, 0, 0, &path);
+ if (fd < 0)
+ return -1;
rc = ioctl(fd, FS_IOC_GETFLAGS, &flag);
if (rc == -1)
- goto err;
+ goto exit;
flag &= ~FS_IMMUTABLE_FL;
rc = ioctl(fd, FS_IOC_SETFLAGS, &flag);
if (rc == -1)
- goto err;
+ goto exit;
close(fd);
+ fd = 0;
rc = unlink(path);
-
-err:
- errno_value = errno;
- if (fd > 0)
- close(fd);
-
- errno = errno_value;
+exit:
+ talloc_free(path);
+ close(fd);
return rc;
}
int efi_get_variable(void *ctx, const char *guidstr, const char *name,
- uint8_t **data, size_t *data_size, uint32_t *attributes)
+ struct efi_data **efi_data)
{
- int fd, errno_value;
+ int fd;
int rc = -1;
- void *p, *buf;
- size_t bufsize = 4096;
- size_t filesize = 0;
- ssize_t sz;
- const char *dir;
+ char *p;
+ char buf[4096];
+ ssize_t total;
+ ssize_t count;
char *path;
- dir = get_efivarfs_path();
- if (!dir)
- return EFAULT;
-
- path = talloc_asprintf(ctx, "%s%s-%s", dir, name, guidstr);
- if (!path)
- return ENOMEM;
+ *efi_data = NULL;
- fd = open(path, O_RDONLY|O_NONBLOCK);
+ fd = efi_open(name, guidstr, 0, 0, &path);
if (fd < 0)
- goto err;
+ goto exit;
- buf = talloc_size(ctx, bufsize);
- if (!buf)
- goto err;
-
- do {
- p = buf + filesize;
- sz = read(fd, p, bufsize);
- if (sz < 0 && errno == EAGAIN) {
- continue;
- } else if (sz == 0) {
- break;
+ for (p = buf, total = 0; ; p = buf + count) {
+ count = read(fd, p, sizeof(buf) - total);
+ if (count < 0) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK)
+ continue;
+
+ pb_log("%s: read failed %s: (%ld) %s\n", __func__, path,
+ count, strerror(errno));
+ goto exit;
}
- filesize += sz;
- } while (1);
+ if (p >= (buf + sizeof(buf))) {
+ pb_log("%s: buffer full %s: (%ld)\n", __func__, path,
+ sizeof(buf));
+ goto exit;
+ }
+ if (count == 0)
+ break;
+ total += count;
+ };
- *attributes = *(uint32_t *)buf;
- *data = (uint8_t *)(buf + sizeof(uint32_t));
- *data_size = strlen(buf + sizeof(uint32_t));
- rc = 0;
+ *efi_data = (void*)talloc_zero_array(ctx, char,
+ sizeof (struct efi_data) + total);
-err:
- errno_value = errno;
- if (fd > 0)
- close(fd);
+ (*efi_data)->attributes = *(uint32_t *)buf;
+ (*efi_data)->data_size = total;
+ (*efi_data)->data = (*efi_data)->fill;
+ memcpy((*efi_data)->data, buf + sizeof (uint32_t), total);
- errno = errno_value;
+ rc = 0;
+exit:
+ talloc_free(path);
+ close(fd);
return rc;
}
-int efi_set_variable(void *ctx, const char *guidstr, const char *name,
- uint8_t *data, size_t data_size, uint32_t attributes)
+int efi_set_variable(const char *guidstr, const char *name,
+ const struct efi_data *efi_data)
{
- int rc = -1, errno_value;
- int fd = -1;
- ssize_t len;
- const char *dir;
- char *path;
+ int rc = -1;
+ int fd;
+ ssize_t count;
void *buf;
size_t bufsize;
- mode_t mask = 0644;
-
- dir = get_efivarfs_path();
- if (!dir)
- return EFAULT;
-
- path = talloc_asprintf(ctx, "%s%s-%s", dir, name, guidstr);
- if (!path)
- return ENOMEM;
+ char *path;
- if (!access(path, F_OK)) {
- rc = efi_del_variable(ctx, guidstr, name);
- if (rc < 0) {
- goto err;
- }
- }
+ efi_del_variable(guidstr, name);
- fd = open(path, O_CREAT|O_WRONLY, mask);
+ fd = efi_open(name, guidstr, O_CREAT | O_WRONLY,
+ S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH, &path);
if (fd < 0)
- goto err;
+ return -1;
- bufsize = sizeof(uint32_t) + data_size;
- buf = talloc_size(ctx, bufsize);
+ bufsize = sizeof(uint32_t) + efi_data->data_size;
+ buf = talloc_size(path, bufsize);
if (!buf)
- goto err;
-
- *(uint32_t *)buf = attributes;
- memcpy(buf + sizeof(uint32_t), data, data_size);
+ goto exit;
- len = write(fd, buf, bufsize);
- if ((size_t)len != bufsize)
- goto err;
- else
- rc = 0;
+ *(uint32_t *)buf = efi_data->attributes;
+ memcpy(buf + sizeof(uint32_t), efi_data->data, efi_data->data_size);
-err:
- errno_value = errno;
- if (fd > 0)
- close(fd);
+ count = write(fd, buf, bufsize);
+ if ((size_t)count != bufsize) {
+ pb_log("%s: write failed %s: (%ld) %s\n", __func__, name,
+ count, strerror(errno));
+ goto exit;
+ }
+ rc = 0;
- errno = errno_value;
+exit:
+ talloc_free(path);
+ close(fd);
return rc;
}
diff --git a/lib/efi/efivar.h b/lib/efi/efivar.h
index ebf73fa..0d44100 100644
--- a/lib/efi/efivar.h
+++ b/lib/efi/efivar.h
@@ -34,13 +34,20 @@
#define EFIVARFS_MAGIC 0xde5e81e4
#endif
+struct efi_data {
+ uint32_t attributes;
+ size_t data_size;
+ void *data;
+ uint8_t fill[0];
+};
+
void set_efivarfs_path(const char *path);
const char *get_efivarfs_path(void);
int efi_get_variable(void *ctx, const char *guidstr, const char *name,
- uint8_t **data, size_t *data_size, uint32_t *attributes);
-int efi_set_variable(void *ctx, const char *guidstr, const char *name,
- uint8_t *data, size_t data_size, uint32_t attributes);
-int efi_del_variable(void *ctx, const char *guidstr, const char *name);
+ struct efi_data **efi_data);
+int efi_set_variable(const char *guidstr, const char *name,
+ const struct efi_data *efi_data);
+int efi_del_variable(const char *guidstr, const char *name);
#endif /* EFIVAR_H */
--
2.14.1
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