[dmidecode] [PATCH 2/3] util: Let callers pass an offset to read_file

[Jean Delvare]

When reading from a dump file, read_file would be more convenient to
use than mem_chunk, but it lacks an offset parameter.
---
 dmidecode.c |    4 ++--
 util.c      |   12 ++++++++++--
 util.h      |    2 +-
 3 files changed, 13 insertions(+), 5 deletions(-)

--- dmidecode.orig/util.c       2017-04-05 14:38:20.159930299 +0200
+++ dmidecode/util.c    2017-04-05 14:38:34.148063132 +0200
@@ -89,7 +89,7 @@ int checksum(const u8 *buf, size_t len)
 }
 
 /*
- * Reads all of file, up to max_len bytes.
+ * Reads all of file from given offset, up to max_len bytes.
  * A buffer of max_len bytes is allocated by this function, and
  * needs to be freed by the caller.
  * This provides a similar usage model to mem_chunk()
@@ -98,7 +98,7 @@ int checksum(const u8 *buf, size_t len)
  * sets max_len to the length actually read.
  *
  */
-void *read_file(size_t *max_len, const char *filename)
+void *read_file(off_t base, size_t *max_len, const char *filename)
 {
        int fd;
        size_t r2 = 0;
@@ -116,6 +116,14 @@ void *read_file(size_t *max_len, const c
                return NULL;
        }
 
+       if (lseek(fd, base, SEEK_SET) == -1)
+       {
+               fprintf(stderr, "%s: ", filename);
+               perror("lseek");
+               p = NULL;
+               goto out;
+       }
+
        if ((p = malloc(*max_len)) == NULL)
        {
                perror("malloc");
--- dmidecode.orig/util.h       2017-04-05 14:38:20.159930299 +0200
+++ dmidecode/util.h    2017-04-05 14:38:34.148063132 +0200
@@ -25,7 +25,7 @@
 #define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
 
 int checksum(const u8 *buf, size_t len);
-void *read_file(size_t *len, const char *filename);
+void *read_file(off_t base, size_t *len, const char *filename);
 void *mem_chunk(off_t base, size_t len, const char *devmem);
 int write_dump(size_t base, size_t len, const void *data, const char 
*dumpfile, int add);
 u64 u64_range(u64 start, u64 end);
--- dmidecode.orig/dmidecode.c  2017-04-05 14:38:20.303931666 +0200
+++ dmidecode/dmidecode.c       2017-04-05 14:38:34.149063141 +0200
@@ -4550,7 +4550,7 @@ static void dmi_table(off_t base, u32 le
                 * result of the kernel truncating the table on parse error.
                 */
                size_t size = len;
-               buf = read_file(&size, devmem);
+               buf = read_file(0, &size, devmem);
                if (!(opt.flags & FLAG_QUIET) && num && size != (size_t)len)
                {
                        fprintf(stderr, "Wrong DMI structures length: %u bytes "
@@ -4862,7 +4862,7 @@ int main(int argc, char * const argv[])
         */
        size = 0x20;
        if (!(opt.flags & FLAG_NO_SYSFS)
-        && (buf = read_file(&size, SYS_ENTRY_FILE)) != NULL)
+        && (buf = read_file(0, &size, SYS_ENTRY_FILE)) != NULL)
        {
                if (!(opt.flags & FLAG_QUIET))
                        printf("Getting SMBIOS data from sysfs.\n");


-- 
Jean Delvare
SUSE L3 Support