The patch titled
gen_init_cpio: expand shell variables in file names
has been added to the -mm tree. Its filename is
gen_init_cpio-expand-shell-variables-in-file-names.patch
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------------------------------------------------------
Subject: gen_init_cpio: expand shell variables in file names
From: "Sally, Gene" <Gene.Sally@xxxxxxxxxxx>
This modifies gen_init_cpio so that lines that specify files can contain
what looks like a shell variable that's expanded during processing.
For example:
file /sbin/kinit ${RFS_BASE}/usr/src/klibc/kinit/kinit 0755 0 0
given RFS_BASE is "/some/directory" in the environment
would be expanded to
file /sbin/kinit /some/directory/usr/src/klibc/kinit/kinit 0755 0 0
If several environment variables appear in a line, they are all expanded
with processing happening from left to right. Undefined variables expand
to a null string. Syntax errors stop processing, letting the existing
error handling show the user offending line.
This helps embedded folks who frequently create several RFS directories
and then switch between them as they're tuning an initramfs. Having just
been such an embedded folk, this seems the most efficient solution.
Signed-off-by: Gene Sally <gene.sally@xxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
usr/gen_init_cpio.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff -puN usr/gen_init_cpio.c~gen_init_cpio-expand-shell-variables-in-file-names usr/gen_init_cpio.c
--- a/usr/gen_init_cpio.c~gen_init_cpio-expand-shell-variables-in-file-names
+++ a/usr/gen_init_cpio.c
@@ -370,6 +370,30 @@ error:
return rc;
}
+static char *cpio_replace_env(char *new_location)
+{
+ char expanded[PATH_MAX + 1];
+ char env_var[PATH_MAX + 1];
+ char *start;
+ char *end;
+
+ for (start = NULL; (start = strstr(new_location, "${")); ) {
+ end = strchr(start, '}');
+ if (start < end) {
+ *env_var = *expanded = '\0';
+ strncat(env_var, start + 2, end - start - 2);
+ strncat(expanded, new_location, start - new_location);
+ strncat(expanded, getenv(env_var), PATH_MAX);
+ strncat(expanded, end + 1, PATH_MAX);
+ strncpy(new_location, expanded, PATH_MAX);
+ } else
+ break;
+ }
+
+ return new_location;
+}
+
+
static int cpio_mkfile_line(const char *line)
{
char name[PATH_MAX + 1];
@@ -415,7 +439,8 @@ static int cpio_mkfile_line(const char *
} else {
dname = name;
}
- rc = cpio_mkfile(dname, location, mode, uid, gid, nlinks);
+ rc = cpio_mkfile(dname, cpio_replace_env(location),
+ mode, uid, gid, nlinks);
fail:
if (dname_len) free(dname);
return rc;
@@ -439,6 +464,7 @@ void usage(const char *prog)
"\n"
"<name> name of the file/dir/nod/etc in the archive\n"
"<location> location of the file in the current filesystem\n"
+ " expands shell variables quoted with ${}\n"
"<target> link target\n"
"<mode> mode/permissions of the file\n"
"<uid> user id (0=root)\n"
_
Patches currently in -mm which might be from Gene.Sally@xxxxxxxxxxx are
gen_init_cpio-expand-shell-variables-in-file-names.patch
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