From 027a73a903af306449710ce12bc09e0e3550c6c9 Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Thu, 4 Aug 2016 10:16:59 -0500
Subject: Make xopen() skip stdin/stdout/stderr, add xopen_stdio() if you want
stdout, add xopenro() that takes one argument and understands "-" means
stdin, and switch over lots of users.
---
lib/lib.c | 2 +-
lib/lib.h | 3 +++
lib/password.c | 2 +-
lib/xwrap.c | 42 +++++++++++++++++++++++++++++++++++++++---
4 files changed, 44 insertions(+), 5 deletions(-)
(limited to 'lib')
diff --git a/lib/lib.c b/lib/lib.c
index 5c7696d0..718ea3ac 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -1008,7 +1008,7 @@ int qstrcmp(const void *a, const void *b)
void create_uuid(char *uuid)
{
// Read 128 random bits
- int fd = xopen("/dev/urandom", O_RDONLY);
+ int fd = xopenro("/dev/urandom");
xreadall(fd, uuid, 16);
close(fd);
diff --git a/lib/lib.h b/lib/lib.h
index c3aa7e72..520a5ed6 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -130,6 +130,9 @@ void xaccess(char *path, int flags);
void xunlink(char *path);
int xcreate(char *path, int flags, int mode);
int xopen(char *path, int flags);
+int xcreate_stdio(char *path, int flags, int mode);
+int xopen_stdio(char *path, int flags);
+int xopenro(char *path);
void xpipe(int *pp);
void xclose(int fd);
int xdup(int fd);
diff --git a/lib/password.c b/lib/password.c
index bf13c441..eab2d669 100644
--- a/lib/password.c
+++ b/lib/password.c
@@ -24,7 +24,7 @@ int get_salt(char *salt, char *algo)
if (al[i].id) s += sprintf(s, "$%c$", '0'+al[i].id);
// Read appropriate number of random bytes for salt
- i = xopen("/dev/urandom", O_RDONLY);
+ i = xopenro("/dev/urandom");
xreadall(i, libbuf, ((len*6)+7)/8);
close(i);
diff --git a/lib/xwrap.c b/lib/xwrap.c
index 7176aae1..a7b7bfcb 100644
--- a/lib/xwrap.c
+++ b/lib/xwrap.c
@@ -318,17 +318,18 @@ void xunlink(char *path)
}
// Die unless we can open/create a file, returning file descriptor.
-int xcreate(char *path, int flags, int mode)
+int xcreate_stdio(char *path, int flags, int mode)
{
int fd = open(path, flags^O_CLOEXEC, mode);
+
if (fd == -1) perror_exit_raw(path);
return fd;
}
// Die unless we can open a file, returning file descriptor.
-int xopen(char *path, int flags)
+int xopen_stdio(char *path, int flags)
{
- return xcreate(path, flags, 0);
+ return xcreate_stdio(path, flags, 0);
}
void xpipe(int *pp)
@@ -350,6 +351,41 @@ int xdup(int fd)
return fd;
}
+// Move file descriptor above stdin/stdout/stderr, using /dev/null to consume
+// old one. (We should never be called with stdin/stdout/stderr closed, but...)
+int notstdio(int fd)
+{
+ while (fd<3) {
+ int fd2 = xdup(fd);
+
+ close(fd);
+ xopen_stdio("/dev/null", O_RDWR);
+ fd = fd2;
+ }
+
+ return fd;
+}
+
+// Create a file but don't return stdin/stdout/stderr
+int xcreate(char *path, int flags, int mode)
+{
+ return notstdio(xcreate_stdio(path, flags, mode));
+}
+
+// Open a file descriptor NOT in stdin/stdout/stderr
+int xopen(char *path, int flags)
+{
+ return notstdio(xopen_stdio(path, flags));
+}
+
+// Open read only, treating "-" as a synonym for stdin.
+int xopenro(char *path)
+{
+ if (!strcmp(path, "-")) return 0;
+
+ return xopen(path, O_RDONLY);
+}
+
FILE *xfdopen(int fd, char *mode)
{
FILE *f = fdopen(fd, mode);
--
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