From: Ruediger Meier <ruediger.meier@xxxxxxxxxxx>
path_vcreate_with_prefix() is going to be removed.
Signed-off-by: Ruediger Meier <ruediger.meier@xxxxxxxxxxx>
---
lib/path.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 96 insertions(+), 15 deletions(-)
diff --git a/lib/path.c b/lib/path.c
index 79c1e7a..94181fe 100644
--- a/lib/path.c
+++ b/lib/path.c
@@ -26,18 +26,60 @@
#include <stdio.h>
#include <inttypes.h>
#include <errno.h>
+#include <sys/stat.h>
#include "all-io.h"
#include "path.h"
#include "nls.h"
#include "c.h"
+static int rootfd = -1;
static size_t prefixlen;
+static char pathbuf_prefix[PATH_MAX];
static char pathbuf[PATH_MAX];
+/* It's a programming error if they try us to use with relative paths. */
+#define PATH_REQUIRE_ABSOLUTE(path) \
+ assert( !path || *path == '/' )
+
+static inline const char *
+path_relative_if_sysroot(const char *p)
+{
+ /* Convert to relative path if we have a prefix (sysroot). Otherwise
+ * openat() functions would ignore the dirfd. */
+ if(p && rootfd >= 0)
+ while(*p && *p == '/') ++p;
+ return p;
+}
+
static const char *
path_vcreate(const char *path, va_list ap)
{
+ const char * p = pathbuf;
+ int rc = vsnprintf(
+ pathbuf, sizeof(pathbuf), path, ap);
+
+ if (rc < 0)
+ goto err;
+ if ((size_t)rc >= sizeof(pathbuf)) {
+ errno = ENAMETOOLONG;
+ goto err;
+ }
+
+ PATH_REQUIRE_ABSOLUTE(p);
+ p = path_relative_if_sysroot(p);
+
+ return p;
+err:
+ /* Only for error messages when we could not construct a path. */
+ strcpy(pathbuf, "path");
+ return NULL;
+}
+
+static const char *
+path_vcreate_with_prefix(const char *path, va_list ap)
+{
+ strcpy(pathbuf, pathbuf_prefix);
int rc = vsnprintf(
pathbuf + prefixlen, sizeof(pathbuf) - prefixlen, path, ap);
@@ -55,30 +97,60 @@ path_get(const char *path, ...)
{
const char *p;
va_list ap;
+ static char userbuf[sizeof(pathbuf)];
va_start(ap, path);
- p = path_vcreate(path, ap);
+ p = path_vcreate_with_prefix(path, ap);
va_end(ap);
+ if (p) {
+ /* do not hand out our global buffer to the user to avoid overlapping
+ * problems in case we get this string back from the user */
+ p = strcpy(userbuf, p);
+ }
+
return p;
}
+/* Get the last used path. Only for error messages. */
+static const char *
+path_last_path(void)
+{
+ if (rootfd < 0) {
+ return pathbuf;
+ } else {
+ char prfx[] = "[sysroot]/"; /* we could also add the real prefix */
+ size_t n = sizeof(prfx) - 1 ;
+ memmove(pathbuf+n, pathbuf, sizeof(pathbuf)-n);
+ pathbuf[sizeof(pathbuf)-1] = '\0';
+ strncpy(pathbuf, prfx, n);
+ return pathbuf;
+ }
+}
+
static FILE *
path_vfopen(const char *mode, int exit_on_error, const char *path, va_list ap)
{
+ int fd;
FILE *f;
const char *p = path_vcreate(path, ap);
if (!p)
goto err;
- f = fopen(p, mode);
- if (!f)
+ fd = openat(rootfd, p, O_RDONLY);
+ if (fd == -1)
+ goto err;
+
+ f = fdopen(fd, mode);
+ if (!f) {
+ close(fd);
goto err;
+ }
return f;
err:
if (exit_on_error)
- err(EXIT_FAILURE, _("cannot open %s"), p ? p : "path");
+ err(EXIT_FAILURE, _("cannot open %s"), path_last_path());
return NULL;
}
@@ -90,13 +162,13 @@ path_vopen(int flags, const char *path, va_list ap)
if (!p)
goto err;
- fd = open(p, flags);
+ fd = openat(rootfd, p, flags);
if (fd == -1)
goto err;
return fd;
err:
- err(EXIT_FAILURE, _("cannot open %s"), p ? p : "path");
+ err(EXIT_FAILURE, _("cannot open %s"), path_last_path());
}
FILE *
@@ -123,7 +195,7 @@ path_read_str(char *result, size_t len, const char *path, ...)
va_end(ap);
if (!fgets(result, len, fd))
- err(EXIT_FAILURE, _("cannot read %s"), pathbuf);
+ err(EXIT_FAILURE, _("cannot read %s"), path_last_path());
fclose(fd);
len = strlen(result);
@@ -144,9 +216,9 @@ path_read_s32(const char *path, ...)
if (fscanf(fd, "%d", &result) != 1) {
if (ferror(fd))
- err(EXIT_FAILURE, _("cannot read %s"), pathbuf);
+ err(EXIT_FAILURE, _("cannot read %s"), path_last_path());
else
- errx(EXIT_FAILURE, _("parse error: %s"), pathbuf);
+ errx(EXIT_FAILURE, _("parse error: %s"), path_last_path());
}
fclose(fd);
return result;
@@ -165,9 +237,9 @@ path_read_u64(const char *path, ...)
if (fscanf(fd, "%"SCNu64, &result) != 1) {
if (ferror(fd))
- err(EXIT_FAILURE, _("cannot read %s"), pathbuf);
+ err(EXIT_FAILURE, _("cannot read %s"), path_last_path());
else
- errx(EXIT_FAILURE, _("parse error: %s"), pathbuf);
+ errx(EXIT_FAILURE, _("parse error: %s"), path_last_path());
}
fclose(fd);
return result;
@@ -197,7 +269,7 @@ path_exist(const char *path, ...)
p = path_vcreate(path, ap);
va_end(ap);
- return p && access(p, F_OK) == 0;
+ return p && faccessat(rootfd, p, F_OK, 0) == 0;
}
#ifdef HAVE_CPU_SET_T
@@ -213,7 +285,7 @@ path_cpuparse(int maxcpus, int islist, const char *path, va_list ap)
fd = path_vfopen("r" UL_CLOEXECSTR, 1, path, ap);
if (!fgets(buf, len, fd))
- err(EXIT_FAILURE, _("cannot read %s"), pathbuf);
+ err(EXIT_FAILURE, _("cannot read %s"), path_last_path());
fclose(fd);
len = strlen(buf);
@@ -265,12 +337,21 @@ path_set_prefix(const char *prefix)
{
size_t len = strlen(prefix);
- if (len >= sizeof(pathbuf) - 1) {
+ /* ignore trivial prefix */
+ if (len == 0)
+ return 0;
+
+ if (len >= sizeof(pathbuf_prefix) - 1) {
errno = ENAMETOOLONG;
return -1;
}
+
+ rootfd = open(prefix, O_RDONLY|O_DIRECTORY|O_CLOEXEC);
+ if (rootfd < 0)
+ return -1;
+
prefixlen = len;
- strcpy(pathbuf, prefix);
+ strcpy(pathbuf_prefix, prefix);
return 0;
}
--
1.8.5.6
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