From 09020f309cb003d15ddc96952784b60d3a6b4d44 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Tue, 11 Jan 2022 15:58:02 +0100
Subject: [PATCH] Make offset a common struct file member for all types

Currently 4 file types have an offset member in their private struct
file part. Make offset a common struct member shared by all file types.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
---
 blkfront.c    |  5 ++---
 include/lib.h |  5 +----
 lib/sys.c     | 14 +++++---------
 tpm_tis.c     | 11 +++++------
 tpmfront.c    | 11 +++++------
 5 files changed, 18 insertions(+), 28 deletions(-)

diff --git a/blkfront.c b/blkfront.c
index 7c8eb74..8137106 100644
--- a/blkfront.c
+++ b/blkfront.c
@@ -563,14 +563,13 @@ int blkfront_open(struct blkfront_dev *dev)
     dev->fd = alloc_fd(FTYPE_BLK);
     printk("blk_open(%s) -> %d\n", dev->nodename, dev->fd);
     files[dev->fd].blk.dev = dev;
-    files[dev->fd].blk.offset = 0;
     return dev->fd;
 }
 
 int blkfront_posix_rwop(int fd, uint8_t* buf, size_t count, int write)
 {
    struct blkfront_dev* dev = files[fd].blk.dev;
-   off_t offset = files[fd].blk.offset;
+   off_t offset = files[fd].offset;
    struct blkfront_aiocb aiocb;
    unsigned long long disksize = dev->info.sectors * dev->info.sector_size;
    unsigned int blocksize = dev->info.sector_size;
@@ -712,7 +711,7 @@ int blkfront_posix_rwop(int fd, uint8_t* buf, size_t count, int write)
    }
 
    free(copybuf);
-   files[fd].blk.offset += rc;
+   files[fd].offset += rc;
    return rc;
 
 }
diff --git a/include/lib.h b/include/lib.h
index df2de9e..4d9b14b 100644
--- a/include/lib.h
+++ b/include/lib.h
@@ -185,6 +185,7 @@ struct evtchn_port_info {
 struct file {
     enum fd_type type;
     bool read;	/* maybe available for read */
+    off_t offset;
     union {
 	struct {
             /* lwIP fd */
@@ -193,7 +194,6 @@ struct file {
 	struct {
             /* FS import fd */
 	    int fd;
-	    off_t offset;
 	} file;
 	struct {
 	    struct evtchn_port_list ports;
@@ -204,7 +204,6 @@ struct file {
 	} tap;
 	struct {
 	    struct blkfront_dev *dev;
-            off_t offset;
 	} blk;
 	struct {
 	    struct kbdfront_dev *dev;
@@ -219,14 +218,12 @@ struct file {
 	struct {
 	   struct tpmfront_dev *dev;
 	   int respgot;
-	   off_t offset;
 	} tpmfront;
 #endif
 #ifdef CONFIG_TPM_TIS
 	struct {
 	   struct tpm_chip *dev;
 	   int respgot;
-	   off_t offset;
 	} tpm_tis;
 #endif
 #ifdef CONFIG_XENBUS
diff --git a/lib/sys.c b/lib/sys.c
index e8d5eb2..e1cea70 100644
--- a/lib/sys.c
+++ b/lib/sys.c
@@ -107,6 +107,7 @@ int alloc_fd(enum fd_type type)
     for (i=0; i<NOFILE; i++) {
 	if (files[i].type == FTYPE_NONE) {
 	    files[i].type = type;
+            files[i].offset = 0;
 	    pthread_mutex_unlock(&fd_lock);
 	    return i;
 	}
@@ -363,25 +364,20 @@ int write(int fd, const void *buf, size_t nbytes)
 
 off_t lseek(int fd, off_t offset, int whence)
 {
-    off_t* target = NULL;
     switch(files[fd].type) {
 #ifdef CONFIG_BLKFRONT
        case FTYPE_BLK:
-          target = &files[fd].blk.offset;
           break;
 #endif
 #ifdef CONFIG_TPMFRONT
        case FTYPE_TPMFRONT:
-          target = &files[fd].tpmfront.offset;
           break;
 #endif
 #ifdef CONFIG_TPM_TIS
        case FTYPE_TPM_TIS:
-          target = &files[fd].tpm_tis.offset;
           break;
 #endif
        case FTYPE_FILE:
-          target = &files[fd].file.offset;
           break;
        default:
           /* Not implemented for this filetype */
@@ -391,10 +387,10 @@ off_t lseek(int fd, off_t offset, int whence)
 
     switch (whence) {
        case SEEK_SET:
-          *target = offset;
+          files[fd].offset = offset;
           break;
        case SEEK_CUR:
-          *target += offset;
+          files[fd].offset += offset;
           break;
        case SEEK_END:
           {
@@ -403,14 +399,14 @@ off_t lseek(int fd, off_t offset, int whence)
              ret = fstat(fd, &st);
              if (ret)
                 return -1;
-             *target = st.st_size + offset;
+             files[fd].offset = st.st_size + offset;
              break;
           }
        default:
           errno = EINVAL;
           return -1;
     }
-    return *target;
+    return files[fd].offset;
 }
 
 int fsync(int fd) {
diff --git a/tpm_tis.c b/tpm_tis.c
index 4a51027..8a632b1 100644
--- a/tpm_tis.c
+++ b/tpm_tis.c
@@ -847,7 +847,7 @@ int tpm_tis_send(struct tpm_chip* tpm, uint8_t* buf, size_t len) {
    if(tpm->fd >= 0) {
       files[tpm->fd].read = false;
       files[tpm->fd].tpm_tis.respgot = 0;
-      files[tpm->fd].tpm_tis.offset = 0;
+      files[tpm->fd].offset = 0;
    }
 #endif
    return len;
@@ -1290,7 +1290,6 @@ int tpm_tis_open(struct tpm_chip* tpm)
    tpm->fd = alloc_fd(FTYPE_TPM_TIS);
    printk("tpm_tis_open() -> %d\n", tpm->fd);
    files[tpm->fd].tpm_tis.dev = tpm;
-   files[tpm->fd].tpm_tis.offset = 0;
    files[tpm->fd].tpm_tis.respgot = 0;
    return tpm->fd;
 }
@@ -1340,13 +1339,13 @@ int tpm_tis_posix_read(int fd, uint8_t* buf, size_t count)
 
 
    /* Handle EOF case */
-   if(files[fd].tpm_tis.offset >= tpm->data_len) {
+   if(files[fd].offset >= tpm->data_len) {
       rc = 0;
    } else {
-      rc = min(tpm->data_len - files[fd].tpm_tis.offset, count);
-      memcpy(buf, tpm->data_buffer + files[fd].tpm_tis.offset, rc);
+      rc = min(tpm->data_len - files[fd].offset, count);
+      memcpy(buf, tpm->data_buffer + files[fd].offset, rc);
    }
-   files[fd].tpm_tis.offset += rc;
+   files[fd].offset += rc;
    /* Reset the data pending flag */
    return rc;
 }
diff --git a/tpmfront.c b/tpmfront.c
index d825b49..8b2a910 100644
--- a/tpmfront.c
+++ b/tpmfront.c
@@ -440,7 +440,7 @@ int tpmfront_send(struct tpmfront_dev* dev, const uint8_t* msg, size_t length)
    if(dev->fd >= 0) {
       files[dev->fd].read = false;
       files[dev->fd].tpmfront.respgot = 0;
-      files[dev->fd].tpmfront.offset = 0;
+      files[dev->fd].offset = 0;
    }
 #endif
    wmb();
@@ -539,7 +539,6 @@ int tpmfront_open(struct tpmfront_dev* dev)
    dev->fd = alloc_fd(FTYPE_TPMFRONT);
    printk("tpmfront_open(%s) -> %d\n", dev->nodename, dev->fd);
    files[dev->fd].tpmfront.dev = dev;
-   files[dev->fd].tpmfront.offset = 0;
    files[dev->fd].tpmfront.respgot = 0;
    return dev->fd;
 }
@@ -589,14 +588,14 @@ int tpmfront_posix_read(int fd, uint8_t* buf, size_t count)
    }
 
    /* handle EOF case */
-   if(files[dev->fd].tpmfront.offset >= dev->resplen) {
+   if(files[dev->fd].offset >= dev->resplen) {
       return 0;
    }
 
    /* Compute the number of bytes and do the copy operation */
-   if((rc = min(count, dev->resplen - files[dev->fd].tpmfront.offset)) != 0) {
-      memcpy(buf, dev->respbuf + files[dev->fd].tpmfront.offset, rc);
-      files[dev->fd].tpmfront.offset += rc;
+   if((rc = min(count, dev->resplen - files[dev->fd].offset)) != 0) {
+      memcpy(buf, dev->respbuf + files[dev->fd].offset, rc);
+      files[dev->fd].offset += rc;
    }
 
    return rc;
-- 
2.39.5