Come up with startswith function.

New function in system.h that returns true if a string has a given
prefix, false otherwise.  Use it in place of strncmp.

Signed-off-by: Martin Liška <mliska@suse.cz>

2 files changed, 19 insertions, 3 deletions

diff --git a/lib/ChangeLog b/lib/ChangeLog
index 371e2133..dd3ebcab 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,3 +1,10 @@
+2021-04-19  Martin Liska  <mliska@suse.cz>
+
+	* system.h (startswith): New function.
+	(pwrite_retry): Cast to char *.
+	(write_retry): Likewise.
+	(pread_retry): Likewise.
+
 2021-02-05  Mark Wielaard  <mark@klomp.org>
 
 	* printversion.c (print_version): Update copyright year.
diff --git a/lib/system.h b/lib/system.h
index 1c478e1c..cdf18ed7 100644
--- a/lib/system.h
+++ b/lib/system.h
@@ -37,6 +37,7 @@
 #include <endian.h>
 #include <byteswap.h>
 #include <unistd.h>
+#include <string.h>
 
 #if __BYTE_ORDER == __LITTLE_ENDIAN
 # define LE32(n)	(n)
@@ -69,6 +70,14 @@
     ((void *) ((char *) memcpy (dest, src, n) + (size_t) n))
 #endif
 
+/* Return TRUE if the start of STR matches PREFIX, FALSE otherwise.  */
+
+static inline int
+startswith (const char *str, const char *prefix)
+{
+  return strncmp (str, prefix, strlen (prefix)) == 0;
+}
+
 /* A special gettext function we use if the strings are too short.  */
 #define sgettext(Str) \
   ({ const char *__res = strrchr (_(Str), '|');			      \
@@ -104,7 +113,7 @@ pwrite_retry (int fd, const void *buf, size_t len, off_t off)
 
   do
     {
-      ssize_t ret = TEMP_FAILURE_RETRY (pwrite (fd, buf + recvd, len - recvd,
+      ssize_t ret = TEMP_FAILURE_RETRY (pwrite (fd, ((char *)buf) + recvd, len - recvd,
 						off + recvd));
       if (ret <= 0)
 	return ret < 0 ? ret : recvd;
@@ -123,7 +132,7 @@ write_retry (int fd, const void *buf, size_t len)
 
   do
     {
-      ssize_t ret = TEMP_FAILURE_RETRY (write (fd, buf + recvd, len - recvd));
+      ssize_t ret = TEMP_FAILURE_RETRY (write (fd, ((char *)buf) + recvd, len - recvd));
       if (ret <= 0)
 	return ret < 0 ? ret : recvd;
 
@@ -141,7 +150,7 @@ pread_retry (int fd, void *buf, size_t len, off_t off)
 
   do
     {
-      ssize_t ret = TEMP_FAILURE_RETRY (pread (fd, buf + recvd, len - recvd,
+      ssize_t ret = TEMP_FAILURE_RETRY (pread (fd, ((char *)buf) + recvd, len - recvd,
 					       off + recvd));
       if (ret <= 0)
 	return ret < 0 ? ret : recvd;