gen_init_cpio: avoid duplicate strlen calls

We determine the filename length for the cpio header, so shouldn't
recalculate it when writing out the filename.

Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/r/20250819032607.28727-5-ddiss@suse.de
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

diff --git a/usr/gen_init_cpio.c b/usr/gen_init_cpio.c
index aa73afd3756c81ccbfdc8a970d92b0a8bfbd287f..729585342e16e2f7110f7ea41f9b67c8fa782b30 100644 (file)
--- a/usr/gen_init_cpio.c
+++ b/usr/gen_init_cpio.c
@@ -25,6 +25,7 @@
 #define str(s) xstr(s)
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
 #define CPIO_HDR_LEN 110
+#define CPIO_TRAILER "TRAILER!!!"
 #define padlen(_off, _align) (((_align) - ((_off) & ((_align) - 1))) % (_align))
 
 static char padding[512];
@@ -40,9 +41,8 @@ struct file_handler {
        int (*handler)(const char *line);
 };
 
-static int push_string(const char *name)
+static int push_buf(const char *name, size_t name_len)
 {
-       unsigned int name_len = strlen(name) + 1;
        ssize_t len;
 
        len = write(outfd, name, name_len);
@@ -69,9 +69,8 @@ static int push_pad(size_t padlen)
        return 0;
 }
 
-static int push_rest(const char *name)
+static int push_rest(const char *name, size_t name_len)
 {
-       unsigned int name_len = strlen(name) + 1;
        ssize_t len;
 
        len = write(outfd, name, name_len);
@@ -85,8 +84,8 @@ static int push_rest(const char *name)
 
 static int cpio_trailer(void)
 {
-       const char name[] = "TRAILER!!!";
        int len;
+       unsigned int namesize = sizeof(CPIO_TRAILER);
 
        len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
               "%08X%08X%08X%08X%08X%08X%08X",
@@ -102,12 +101,12 @@ static int cpio_trailer(void)
                0,                      /* minor */
                0,                      /* rmajor */
                0,                      /* rminor */
-               (unsigned)strlen(name)+1, /* namesize */
+               namesize,               /* namesize */
                0);                     /* chksum */
        offset += len;
 
        if (len != CPIO_HDR_LEN ||
-           push_rest(name) < 0 ||
+           push_rest(CPIO_TRAILER, namesize) < 0 ||
            push_pad(padlen(offset, 512)) < 0)
                return -1;
 
@@ -118,9 +117,12 @@ static int cpio_mkslink(const char *name, const char *target,
                         unsigned int mode, uid_t uid, gid_t gid)
 {
        int len;
+       unsigned int namesize, targetsize = strlen(target) + 1;
 
        if (name[0] == '/')
                name++;
+       namesize = strlen(name) + 1;
+
        len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
               "%08X%08X%08X%08X%08X%08X%08X",
                do_csum ? "070702" : "070701", /* magic */
@@ -130,19 +132,19 @@ static int cpio_mkslink(const char *name, const char *target,
                (long) gid,             /* gid */
                1,                      /* nlink */
                (long) default_mtime,   /* mtime */
-               (unsigned)strlen(target)+1, /* filesize */
+               targetsize,             /* filesize */
                3,                      /* major */
                1,                      /* minor */
                0,                      /* rmajor */
                0,                      /* rminor */
-               (unsigned)strlen(name) + 1,/* namesize */
+               namesize,               /* namesize */
                0);                     /* chksum */
        offset += len;
 
        if (len != CPIO_HDR_LEN ||
-           push_string(name) < 0 ||
+           push_buf(name, namesize) < 0 ||
            push_pad(padlen(offset, 4)) < 0 ||
-           push_string(target) < 0 ||
+           push_buf(target, targetsize) < 0 ||
            push_pad(padlen(offset, 4)) < 0)
                return -1;
 
@@ -172,9 +174,12 @@ static int cpio_mkgeneric(const char *name, unsigned int mode,
                       uid_t uid, gid_t gid)
 {
        int len;
+       unsigned int namesize;
 
        if (name[0] == '/')
                name++;
+       namesize = strlen(name) + 1;
+
        len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
               "%08X%08X%08X%08X%08X%08X%08X",
                do_csum ? "070702" : "070701", /* magic */
@@ -189,12 +194,12 @@ static int cpio_mkgeneric(const char *name, unsigned int mode,
                1,                      /* minor */
                0,                      /* rmajor */
                0,                      /* rminor */
-               (unsigned)strlen(name) + 1,/* namesize */
+               namesize,               /* namesize */
                0);                     /* chksum */
        offset += len;
 
        if (len != CPIO_HDR_LEN ||
-           push_rest(name) < 0)
+           push_rest(name, namesize) < 0)
                return -1;
 
        return 0;
@@ -265,6 +270,7 @@ static int cpio_mknod(const char *name, unsigned int mode,
                       unsigned int maj, unsigned int min)
 {
        int len;
+       unsigned int namesize;
 
        if (dev_type == 'b')
                mode |= S_IFBLK;
@@ -273,6 +279,8 @@ static int cpio_mknod(const char *name, unsigned int mode,
 
        if (name[0] == '/')
                name++;
+       namesize = strlen(name) + 1;
+
        len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
               "%08X%08X%08X%08X%08X%08X%08X",
                do_csum ? "070702" : "070701", /* magic */
@@ -287,12 +295,12 @@ static int cpio_mknod(const char *name, unsigned int mode,
                1,                      /* minor */
                maj,                    /* rmajor */
                min,                    /* rminor */
-               (unsigned)strlen(name) + 1,/* namesize */
+               namesize,               /* namesize */
                0);                     /* chksum */
        offset += len;
 
        if (len != CPIO_HDR_LEN ||
-           push_rest(name) < 0)
+           push_rest(name, namesize) < 0)
                return -1;
 
        return 0;
@@ -426,7 +434,7 @@ static int cpio_mkfile(const char *name, const char *location,
                offset += len;
 
                if (len != CPIO_HDR_LEN ||
-                   push_string(name) < 0 ||
+                   push_buf(name, namesize) < 0 ||
                    push_pad(padlen(offset, 4)) < 0)
                        goto error;