fw_env: make flash_io() take buffer as an argument

It's usually easier to understand code & follow it if all arguments are
passed explicitly. Many coding styles also discourage using global
variables.

Behaviour of flash_io() was a bit unintuitive as it was writing to a
buffer referenced in a global struct. That required developers to
remember how it works and sometimes required hacking "environment"
global struct variable to read data into a proper buffer.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
index 3da75be7830f134662b66db1ed2eaf05fb761c44..a738b910c291308f14db0b2d56c8ff09b48fd393 100644 (file)
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -346,7 +346,7 @@ static int ubi_write(int fd, const void *buf, size_t count)
        return 0;
 }
 
-static int flash_io(int mode);
+static int flash_io(int mode, void *buf, size_t count);
 static int parse_config(struct env_opts *opts);
 
 #if defined(CONFIG_FILE)
@@ -516,7 +516,7 @@ int fw_env_flush(struct env_opts *opts)
        *environment.crc = crc32(0, (uint8_t *) environment.data, ENV_SIZE);
 
        /* write environment back to flash */
-       if (flash_io(O_RDWR)) {
+       if (flash_io(O_RDWR, environment.image, CUR_ENVSIZE)) {
                fprintf(stderr, "Error: can't write fw_env to flash\n");
                return -1;
        }
@@ -1185,7 +1185,8 @@ static int flash_flag_obsolete(int dev, int fd, off_t offset)
        return rc;
 }
 
-static int flash_write(int fd_current, int fd_target, int dev_target)
+static int flash_write(int fd_current, int fd_target, int dev_target, void *buf,
+                      size_t count)
 {
        int rc;
 
@@ -1212,11 +1213,10 @@ static int flash_write(int fd_current, int fd_target, int dev_target)
        if (IS_UBI(dev_target)) {
                if (ubi_update_start(fd_target, CUR_ENVSIZE) < 0)
                        return -1;
-               return ubi_write(fd_target, environment.image, CUR_ENVSIZE);
+               return ubi_write(fd_target, buf, count);
        }
 
-       rc = flash_write_buf(dev_target, fd_target, environment.image,
-                            CUR_ENVSIZE);
+       rc = flash_write_buf(dev_target, fd_target, buf, count);
        if (rc < 0)
                return rc;
 
@@ -1235,17 +1235,17 @@ static int flash_write(int fd_current, int fd_target, int dev_target)
        return 0;
 }
 
-static int flash_read(int fd)
+static int flash_read(int fd, void *buf, size_t count)
 {
        int rc;
 
        if (IS_UBI(dev_current)) {
                DEVTYPE(dev_current) = MTD_ABSENT;
 
-               return ubi_read(fd, environment.image, CUR_ENVSIZE);
+               return ubi_read(fd, buf, count);
        }
 
-       rc = flash_read_buf(dev_current, fd, environment.image, CUR_ENVSIZE,
+       rc = flash_read_buf(dev_current, fd, buf, count,
                            DEVOFFSET(dev_current));
        if (rc != CUR_ENVSIZE)
                return -1;
@@ -1291,7 +1291,7 @@ err:
        return rc;
 }
 
-static int flash_io_write(int fd_current)
+static int flash_io_write(int fd_current, void *buf, size_t count)
 {
        int fd_target = -1, rc, dev_target;
        const char *dname, *target_temp = NULL;
@@ -1322,7 +1322,7 @@ static int flash_io_write(int fd_current)
                        fd_target = fd_current;
        }
 
-       rc = flash_write(fd_current, fd_target, dev_target);
+       rc = flash_write(fd_current, fd_target, dev_target, buf, count);
 
        if (fsync(fd_current) && !(errno == EINVAL || errno == EROFS)) {
                fprintf(stderr,
@@ -1377,7 +1377,7 @@ static int flash_io_write(int fd_current)
        return rc;
 }
 
-static int flash_io(int mode)
+static int flash_io(int mode, void *buf, size_t count)
 {
        int fd_current, rc;
 
@@ -1391,9 +1391,9 @@ static int flash_io(int mode)
        }
 
        if (mode == O_RDWR) {
-               rc = flash_io_write(fd_current);
+               rc = flash_io_write(fd_current, buf, count);
        } else {
-               rc = flash_read(fd_current);
+               rc = flash_read(fd_current, buf, count);
        }
 
        if (close(fd_current)) {
@@ -1455,7 +1455,7 @@ int fw_env_open(struct env_opts *opts)
        }
 
        dev_current = 0;
-       if (flash_io(O_RDONLY)) {
+       if (flash_io(O_RDONLY, environment.image, CUR_ENVSIZE)) {
                ret = -EIO;
                goto open_cleanup;
        }
@@ -1490,7 +1490,7 @@ int fw_env_open(struct env_opts *opts)
                 * other pointers in environment still point inside addr0
                 */
                environment.image = addr1;
-               if (flash_io(O_RDONLY)) {
+               if (flash_io(O_RDONLY, environment.image, CUR_ENVSIZE)) {
                        ret = -EIO;
                        goto open_cleanup;
                }