Cleaup read() and write() variants, plus a couple of new functions like

xlseek and fdlength() for the new mkswap.


git-svn-id: svn://busybox.net/trunk/busybox@15703 69ca8d6d-28ef-0310-b511-8ec308f3f277

8 files changed, 84 insertions, 32 deletions

diff --git a/libbb/change_identity.c b/libbb/change_identity.c
index adebad8ed..74ffccbd3 100644
--- a/libbb/change_identity.c
+++ b/libbb/change_identity.c
@@ -46,10 +46,8 @@ const char *change_identity_e2str ( const struct passwd *pw )
                 return "cannot set groups";
         endgrent ( );
 
-        if ( setgid ( pw-> pw_gid ))
-                return "cannot set group id";
-        if ( setuid ( pw->pw_uid ))
-                return "cannot set user id";
+        xsetgid(pw-> pw_gid);
+        xsetuid(pw->pw_uid);
         return NULL;
 }
 
diff --git a/libbb/copyfd.c b/libbb/copyfd.c
index e2c542e32..0c4f7a054 100644
--- a/libbb/copyfd.c
+++ b/libbb/copyfd.c
@@ -30,24 +30,24 @@ static ssize_t bb_full_fd_action(int src_fd, int dst_fd, size_t size)
         if (src_fd < 0) goto out;
         while (!size || total < size)
         {
-                ssize_t wrote, xread;
+                ssize_t wr, rd;
 
-                xread = safe_read(src_fd, buffer,
+                rd = safe_read(src_fd, buffer,
                                 (!size || size - total > BUFSIZ) ? BUFSIZ : size - total);
 
-                if (xread > 0) {
+                if (rd > 0) {
                         /* A -1 dst_fd means we need to fake it... */
-                        wrote = (dst_fd < 0) ? xread : bb_full_write(dst_fd, buffer, xread);
-                        if (wrote < xread) {
+                        wr = (dst_fd < 0) ? rd : full_write(dst_fd, buffer, rd);
+                        if (wr < rd) {
                                 bb_perror_msg(bb_msg_write_error);
                                 break;
                         }
-                        total += wrote;
+                        total += wr;
                         if (total == size) status = 0;
-                } else if (xread < 0) {
+                } else if (rd < 0) {
                         bb_perror_msg(bb_msg_read_error);
                         break;
-                } else if (xread == 0) {
+                } else if (rd == 0) {
                         /* All done. */
                         status = 0;
                         break;
diff --git a/libbb/create_icmp6_socket.c b/libbb/create_icmp6_socket.c
index d8ff35a0a..c3d1b5578 100644
--- a/libbb/create_icmp6_socket.c
+++ b/libbb/create_icmp6_socket.c
@@ -32,7 +32,7 @@ int create_icmp6_socket(void)
         }
 
         /* drop root privs if running setuid */
-        setuid(getuid());
+        xsetuid(getuid());
 
         return sock;
 }
diff --git a/libbb/create_icmp_socket.c b/libbb/create_icmp_socket.c
index 26120a66d..431c4d8a7 100644
--- a/libbb/create_icmp_socket.c
+++ b/libbb/create_icmp_socket.c
@@ -31,7 +31,7 @@ int create_icmp_socket(void)
         }
 
         /* drop root privs if running setuid */
-        setuid(getuid());
+        xsetuid(getuid());
 
         return sock;
 }
diff --git a/libbb/full_read.c b/libbb/full_read.c
index 8d64bfb90..b5837d5bd 100644
--- a/libbb/full_read.c
+++ b/libbb/full_read.c
@@ -17,7 +17,7 @@
  * Returns the amount read, or -1 on an error.
  * A short read is returned on an end of file.
  */
-ssize_t bb_full_read(int fd, void *buf, size_t len)
+ssize_t full_read(int fd, void *buf, size_t len)
 {
         ssize_t cc;
         ssize_t total;
diff --git a/libbb/full_write.c b/libbb/full_write.c
index 3d6d40184..d812d04b4 100644
--- a/libbb/full_write.c
+++ b/libbb/full_write.c
@@ -16,7 +16,7 @@
  * This does multiple writes as necessary.
  * Returns the amount written, or -1 on an error.
  */
-ssize_t bb_full_write(int fd, const void *buf, size_t len)
+ssize_t full_write(int fd, const void *buf, size_t len)
 {
         ssize_t cc;
         ssize_t total;
diff --git a/libbb/loop.c b/libbb/loop.c
index b9caa973b..0b05cd75f 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -3,6 +3,7 @@
  * Utility routines.
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 2005 by Rob Landley <rob@landley.net>
  *
  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index d843414f9..8562a4fcb 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