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elfctl: allow features to be specified by value

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This will allow elfctl on older releases to set bits that are not yet
known there, so that the binary will have the correct settings applied
if run on a later FreeBSD version.

PR:		252629 (related)
Suggested by:	kib
Reviewed by:	gbe (manpage, earlier), kib
MFC after:	3 days
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D28284
This commit is contained in:
Ed Maste 2021-01-22 12:22:35 -05:00
parent 57a543d8b8
commit 86f33b5fcf
2 changed files with 35 additions and 5 deletions
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15
usr.bin/elfctl/elfctl.1
View File

@ -26,7 +26,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd January 12, 2021
.Dd January 22, 2021
.Dt ELFCTL 1
.Os
.Sh NAME
@ -64,7 +64,8 @@ to turn on the features,
to turn off the features,
.Dq Li =
to only turn on the given features.
A comma separated list of feature names follows the operation.
A comma separated list of feature names or numeric values follows the
operation.
.El
.Pp
If
@ -86,6 +87,16 @@ command:
elfctl file
elfctl -e +aslr file
.Ed
.Pp
Features may be specified as numerical values:
.Bd -literal -offset -indent
elfctl -e =0x0001,0x0004 file
.Ed
.Pp
Features may also be specified as a single combined value:
.Bd -literal -offset -indent
elfctl -e =0x5 file
.Ed
.Sh HISTORY
.Nm
first appeared in

25
usr.bin/elfctl/elfctl.c
View File

@ -33,7 +33,9 @@
#include <sys/endian.h>
#include <sys/stat.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <gelf.h>
#include <getopt.h>
@ -245,9 +247,26 @@ convert_to_feature_val(char *feature_str, uint32_t *feature_val)
}
}
if (i == len) {
warnx("%s is not a valid feature", feature);
if (!iflag)
return (false);
if (isdigit(feature[0])) {
char *eptr;
long val;
errno = 0;
val = strtol(feature, &eptr, 0);
if (eptr == feature || *eptr != '\0')
errno = EINVAL;
else if (val > UINT_MAX)
errno = ERANGE;
if (errno != 0) {
warn("%s invalid", feature);
return (false);
}
input != val;
} else {
warnx("%s is not a valid feature", feature);
if (!iflag)
return (false);
}
}
}