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authorRob Landley2006-07-16 08:14:35 +0000
committerRob Landley2006-07-16 08:14:35 +0000
commit534374755d618c9c36c9940c82756241c4b25a67 (patch)
treefac906b4fa40a68c53cecf20215a7a25b3b1cab6 /libbb/xfuncs.c
parentafb94ecf2bb6c53ce2a381d6ce45a426243c76d9 (diff)
downloadbusybox-534374755d618c9c36c9940c82756241c4b25a67.zip
busybox-534374755d618c9c36c9940c82756241c4b25a67.tar.gz
Cleaup read() and write() variants, plus a couple of new functions like
xlseek and fdlength() for the new mkswap.
Diffstat (limited to 'libbb/xfuncs.c')
-rw-r--r--libbb/xfuncs.c85
1 files changed, 69 insertions, 16 deletions
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index d843414..8562a4f 100644
--- a/libbb/xfuncs.c
+++ b/libbb/xfuncs.c
@@ -120,40 +120,55 @@ int bb_xopen3(const char *pathname, int flags, int mode)
#endif
#ifdef L_xread
-ssize_t bb_xread(int fd, void *buf, size_t count)
+
+// Die with an error message if we can't read the entire buffer.
+
+void xread(int fd, void *buf, size_t count)
{
- ssize_t size;
+ while (count) {
+ ssize_t size;
- size = read(fd, buf, count);
- if (size < 0) {
- bb_perror_msg_and_die(bb_msg_read_error);
+ if ((size = safe_read(fd, buf, count)) < 1)
+ bb_error_msg_and_die("Short read");
+ count -= size;
+ buf = ((char *) buf) + size;
}
- return(size);
}
#endif
-#ifdef L_xread_all
-void bb_xread_all(int fd, void *buf, size_t count)
-{
- ssize_t size;
+#ifdef L_xwrite
+// Die with an error message if we can't write the entire buffer.
+
+void xwrite(int fd, void *buf, size_t count)
+{
while (count) {
- if ((size = bb_xread(fd, buf, count)) == 0) { /* EOF */
- bb_error_msg_and_die("Short read");
- }
+ ssize_t size;
+
+ if ((size = safe_write(fd, buf, count)) < 1)
+ bb_error_msg_and_die("Short write");
count -= size;
buf = ((char *) buf) + size;
}
- return;
+}
+#endif
+
+#ifdef L_xlseek
+
+// Die if we can't lseek to the right spot.
+
+void xlseek(int fd, off_t offset, int whence)
+{
+ if (whence != lseek(fd, offset, whence)) bb_error_msg_and_die("lseek");
}
#endif
#ifdef L_xread_char
-unsigned char bb_xread_char(int fd)
+unsigned char xread_char(int fd)
{
char tmp;
- bb_xread_all(fd, &tmp, 1);
+ xread(fd, &tmp, 1);
return(tmp);
}
@@ -294,3 +309,41 @@ void xsetuid(uid_t uid)
if (setuid(uid)) bb_error_msg_and_die("setuid");
}
#endif
+
+#ifdef L_fdlength
+off_t fdlength(int fd)
+{
+ off_t bottom = 0, top = 0, pos;
+ long size;
+
+ // If the ioctl works for this, return it.
+
+ if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;
+
+ // If not, do a binary search for the last location we can read.
+
+ do {
+ char temp;
+
+ pos = bottom + (top - bottom) / 2;;
+
+ // If we can read from the current location, it's bigger.
+
+ if (lseek(fd, pos, 0)>=0 && safe_read(fd, &temp, 1)==1) {
+ if (bottom == top) bottom = top = (top+1) * 2;
+ else bottom = pos;
+
+ // If we can't, it's smaller.
+
+ } else {
+ if (bottom == top) {
+ if (!top) return 0;
+ bottom = top/2;
+ }
+ else top = pos;
+ }
+ } while (bottom + 1 != top);
+
+ return pos + 1;
+}
+#endif