mmap: accept non-PROT_WRITE MAP_SHARED mappings

Currently we don't accept writable file mmap()s, as there is no
system in place to guarantee dirty buffers would make it back to
disk. But we can actually accept MAP_SHARED for PROT_READ mappings,
meaning the ranges aren't writable at all (and no private copy is
made as with MAP_PRIVATE), as it turns out a fairly large class of
usage.

	. fail writable MAP_SHARED mappings at runtime
	. reduces some minix-specific patches
	. lets binutils gold build on minix without further patching

Change-Id: If2896c0a555328ac5b324afa706063fc6d86519e

diff --git a/common/lib/libprop/prop_object.c b/common/lib/libprop/prop_object.c
index 12e0403553d9201e591dbd757a07551d1fd757ea..7a79e1934224cd882f6fa03ddcacf745a26acda9 100644 (file)
--- a/common/lib/libprop/prop_object.c
+++ b/common/lib/libprop/prop_object.c
@@ -942,13 +942,9 @@ _prop_object_internalize_map_file(const char *fname)
        if ((sb.st_size & pgmask) == 0)
                need_guard = true;
 
-#ifndef __minix
        mf->poimf_xml = mmap(NULL, need_guard ? mf->poimf_mapsize + pgsize
                                              : mf->poimf_mapsize,
                            PROT_READ, MAP_FILE|MAP_SHARED, fd, (off_t)0);
-#else
-       mf->poimf_xml = MAP_FAILED;
-#endif
        (void) close(fd);
        if (mf->poimf_xml == MAP_FAILED) {
                _PROP_FREE(mf, M_TEMP);

diff --git a/lib/libc/cdb/cdbr.c b/lib/libc/cdb/cdbr.c
index 0fe919625495763301fec69429571b30eaae950f..2cc534db63ca2729b8c5638209dd32cee767670d 100644 (file)
--- a/lib/libc/cdb/cdbr.c
+++ b/lib/libc/cdb/cdbr.c
@@ -57,10 +57,6 @@ __RCSID("$NetBSD: cdbr.c,v 1.4 2012/09/27 00:37:43 joerg Exp $");
 #include <string.h>
 #include <unistd.h>
 
-#if defined(__minix) && !defined(MAP_SHARED)
-#define MAP_SHARED MAP_PRIVATE /* LSC: We lose some memory, but it's OK as this is RO. */
-#endif /* defined(__minix) && !defined(MAP_SHARED) */
-
 #ifdef __weak_alias
 __weak_alias(cdbr_close,_cdbr_close)
 __weak_alias(cdbr_find,_cdbr_find)

diff --git a/lib/libc/nls/catopen.c b/lib/libc/nls/catopen.c
index eb81b1aecc15e7e2e5059c8eb5046d1b1b86fea4..b32c2479fa55d3402f41c55c1a88e3ef35758d9f 100644 (file)
--- a/lib/libc/nls/catopen.c
+++ b/lib/libc/nls/catopen.c
@@ -61,10 +61,6 @@ __RCSID("$NetBSD: catopen.c,v 1.32 2013/08/19 08:03:34 joerg Exp $");
 #define NLS_DEFAULT_PATH "/usr/share/nls/%L/%N.cat:/usr/share/nls/%N/%L"
 #define NLS_DEFAULT_LANG "C"
 
-#if defined(__minix) && !defined(MAP_SHARED)
-#define MAP_SHARED MAP_PRIVATE /* LSC: We lose some memory, but it's OK as this is RO. */
-#endif /* defined(__minix) && !defined(MAP_SHARED) */
-
 __weak_alias(catopen, _catopen)
 __weak_alias(catopen_l, _catopen_l)
 

diff --git a/libexec/ftpd/ftpd.c b/libexec/ftpd/ftpd.c
index 179b7dd7950001b62a63c57ab57c50d38ae02e73..d230004bf56989fa645985ae7c12f16100cb153e 100644 (file)
--- a/libexec/ftpd/ftpd.c
+++ b/libexec/ftpd/ftpd.c
@@ -2232,7 +2232,6 @@ send_data_with_mmap(int filefd, int netfd, const struct stat *st, int isdata)
                (void)gettimeofday(&then, NULL);
        } else
                bufrem = winsize;
-#if !defined(__minix)
        while (1) {
                mapsize = MIN(filesize - off, winsize);
                if (mapsize == 0)
@@ -2244,10 +2243,14 @@ send_data_with_mmap(int filefd, int netfd, const struct stat *st, int isdata)
                                goto try_read;
                        return (SS_FILE_ERROR);
                }
+#ifndef __minix
                (void) madvise(win, mapsize, MADV_SEQUENTIAL);
+#endif
                error = write_data(netfd, win, mapsize, &bufrem, &then,
                    isdata);
+#ifndef __minix
                (void) madvise(win, mapsize, MADV_DONTNEED);
+#endif
                munmap(win, mapsize);
                if (urgflag && handleoobcmd())
                        return (SS_ABORTED);
@@ -2257,7 +2260,6 @@ send_data_with_mmap(int filefd, int netfd, const struct stat *st, int isdata)
        }
        return (SS_SUCCESS);
 
-#endif /* !defined(__minix) */
  try_read:
        return (send_data_with_read(filefd, netfd, st, isdata));
 }

diff --git a/libexec/ld.elf_so/map_object.c b/libexec/ld.elf_so/map_object.c
index 7beafee0698a0c94fa8e54cde53bc168f1f165cb..ae178ea8664652023bdaa44a7a4a2435e7171c25 100644 (file)
--- a/libexec/ld.elf_so/map_object.c
+++ b/libexec/ld.elf_so/map_object.c
@@ -52,10 +52,6 @@ __RCSID("$NetBSD: map_object.c,v 1.52 2013/08/03 13:17:05 skrll Exp $");
 #if defined(__minix)
 #define MINIXVERBOSE 0
 
-#ifndef MAP_SHARED
-#define MAP_SHARED MAP_PRIVATE /* minix: MAP_SHARED should be MAP_PRIVATE */
-#endif
-
 #if MINIXVERBOSE
 #include <stdio.h>
 #endif

diff --git a/libexec/ld.elf_so/paths.c b/libexec/ld.elf_so/paths.c
index d763cfc5dd328489444016e0882ed3073a1628d3..6f5c57ec9cd497bf08213815871456b39d29ac21 100644 (file)
--- a/libexec/ld.elf_so/paths.c
+++ b/libexec/ld.elf_so/paths.c
@@ -61,15 +61,13 @@ __RCSID("$NetBSD: paths.c,v 1.41 2013/05/06 08:02:20 skrll Exp $");
 static Search_Path *_rtld_find_path(Search_Path *, const char *, size_t);
 static Search_Path **_rtld_append_path(Search_Path **, Search_Path **,
     const char *, const char *, const char *);
-#if !defined(__minix)
 static void _rtld_process_mapping(Library_Xform **, const char *,
     const char *);
-#endif /* !defined(__minix) */
 static char *exstrdup(const char *, const char *);
-#if !defined(__minix)
 static const char *getstr(const char **, const char *, const char *);
 static const char *getcstr(const char **, const char *, const char *);
 static const char *getword(const char **, const char *, const char *);
+#if !defined(__minix)
 static int matchstr(const char *, const char *, const char *);
 #endif /* !defined(__minix) */
 
@@ -90,7 +88,6 @@ exstrdup(const char *bp, const char *ep)
        return (cp);
 }
 
-#if !defined(__minix)
 /*
  * Like strsep(), but takes end of string and doesn't put any NUL.  To
  * detect empty string, compare `*p' and return value.
@@ -149,6 +146,7 @@ getword(const char **p, const char *ep, const char *delim)
        return (getstr(p, ep, delim));
 }
 
+#if !defined(__minix)
 /*
  * Match `bp' against NUL terminated string pointed by `p'.
  */
@@ -234,7 +232,6 @@ _rtld_add_paths(const char *execname, Search_Path **path_p, const char *pathstr)
        }
 }
 
-#if !defined(__minix)
 /*
  * Process library mappings of the form:
  *     <library_name>  <machdep_variable> <value,...:library_name,...> ...
@@ -340,17 +337,11 @@ cleanup:
                xfree(hwptr->name);
        xfree(hwptr);
 }
-#endif /* !defined(__minix) */
 
 void
 _rtld_process_hints(const char *execname, Search_Path **path_p,
     Library_Xform **lib_p, const char *fname)
 {
-
-#if defined(__minix)
-       /* Minix doesn't support MAP_SHARED. */
-       return;
-#else
        int fd;
        char *buf, small[128];
        const char *b, *ep, *ptr;
@@ -421,7 +412,6 @@ _rtld_process_hints(const char *execname, Search_Path **path_p,
 
        if (buf != small)
                (void)munmap(buf, sz);
-#endif /* defined(__minix) */
 }
 
 #if !defined(__minix)

diff --git a/servers/vm/mmap.c b/servers/vm/mmap.c
index 62c0f432bfffeb8143fbdb532245afd425b47e09..405e5fc791cb94599fc79242a874849b2556fce5 100644 (file)
--- a/servers/vm/mmap.c
+++ b/servers/vm/mmap.c
@@ -256,9 +256,10 @@ int do_mmap(message *m)
                /* File mapping might be disabled */
                if(!enable_filemap) return ENXIO;
 
-               /* files get private copies of pages on writes. */
-               if(!(m->VMM_FLAGS & MAP_PRIVATE)) {
-                       printf("VM: mmap file must MAP_PRIVATE\n");
+               /* For files, we only can't accept writable MAP_SHARED
+                * mappings.
+                */
+               if((m->VMM_FLAGS & MAP_SHARED) && (m->VMM_PROT & PROT_WRITE)) {
                        return ENXIO;
                }
 

diff --git a/sys/sys/mman.h b/sys/sys/mman.h
index 19df99d08d00f48460f19a517be33cfa6f0afad6..91e3fa02fb40ba2a08a354292bba87c9247ddae5 100644 (file)
--- a/sys/sys/mman.h
+++ b/sys/sys/mman.h
@@ -68,9 +68,7 @@ typedef       __off_t         off_t;          /* file offset */
  * Flags contain sharing type and options.
  * Sharing types; choose one.
  */
-#if !defined(__minix)
 #define        MAP_SHARED      0x0001  /* share changes */
-#endif /* !defined(__minix) */
 #define        MAP_PRIVATE     0x0002  /* changes are private */
 
 #ifdef _KERNEL

diff --git a/test/test74.c b/test/test74.c
index 7d2d23fb2c0fa890c78444efa1f3dc9995815634..252a2dfbd555199219fbc438997b699c11e462d7 100644 (file)
--- a/test/test74.c
+++ b/test/test74.c
@@ -403,6 +403,16 @@ void basic_regression(void)
        fd2 = open("../testsh2", O_RDONLY);
        if(fd1 < 0 || fd2 < 0) { e(2); }
 
+       /* just check that we can't mmap() a file writable */
+       if(mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FILE, fd1, 0) != MAP_FAILED) {
+               e(1);
+       }
+
+       /* check that we can mmap() a file MAP_SHARED readonly */
+       if(mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED | MAP_FILE, fd1, 0) == MAP_FAILED) {
+               e(1);
+       }
+
        /* clear cache of files before mmap so pages won't be present already */
        if(fcntl(fd1, F_FLUSH_FS_CACHE) < 0) { e(1); }
        if(fcntl(fd2, F_FLUSH_FS_CACHE) < 0) { e(1); }

diff --git a/usr.bin/msgc/msg_sys.def b/usr.bin/msgc/msg_sys.def
index bc19d260f7153f6d53c7d9727c6ccdd9a70145c5..1b1ba4e400801d318ddc298827d2e190b5dca132 100644 (file)
--- a/usr.bin/msgc/msg_sys.def
+++ b/usr.bin/msgc/msg_sys.def
@@ -104,11 +104,7 @@ msg_file(const char *file)
        if (fd == -1)
                return -1;
        msgmapsz = lseek(fd, 0, SEEK_END);
-#ifdef __minix
-       msgmap = mmap(0, msgmapsz, PROT_READ, MAP_PRIVATE, fd, 0);
-#else /* ! __minix */
        msgmap = mmap(0, msgmapsz, PROT_READ, MAP_SHARED, fd, 0);
-#endif /* ! __minix */
        close(fd);
        if (msgmap == MAP_FAILED)
                return -1;

diff --git a/usr.bin/xinstall/xinstall.c b/usr.bin/xinstall/xinstall.c
index 73f96897eea89b0eb22b181f136d41a6c4a7c40d..83acd42ac55690918aeec4d3ecb90512df95d80d 100644 (file)
--- a/usr.bin/xinstall/xinstall.c
+++ b/usr.bin/xinstall/xinstall.c
@@ -819,9 +819,7 @@ copy(int from_fd, char *from_name, int to_fd, char *to_name, off_t size)
 {
        ssize_t nr, nw;
        int     serrno;
-#if !defined(__minix)
        u_char  *p;
-#endif /* !defined(__minix) */
        u_char  buf[MAXBSIZE];
        MD5_CTX         ctxMD5;
        RMD160_CTX      ctxRMD160;
@@ -868,15 +866,12 @@ copy(int from_fd, char *from_name, int to_fd, char *to_name, off_t size)
                 */
 
                if (size <= 8 * 1048576) {
-#if defined(__minix)
-                       goto mmap_failed;
-#else
                        if ((p = mmap(NULL, (size_t)size, PROT_READ,
                            MAP_FILE|MAP_SHARED, from_fd, (off_t)0))
                            == MAP_FAILED) {
                                goto mmap_failed;
                        }
-#if defined(MADV_SEQUENTIAL) && !defined(__APPLE__)
+#if defined(MADV_SEQUENTIAL) && !defined(__APPLE__) && !defined(__minix)
                        if (madvise(p, (size_t)size, MADV_SEQUENTIAL) == -1
                            && errno != EOPNOTSUPP)
                                warnx("madvise: %s", strerror(errno));
@@ -911,7 +906,6 @@ copy(int from_fd, char *from_name, int to_fd, char *to_name, off_t size)
                                break;
                        }
                        (void)munmap(p, size);
-#endif /* defined(__minix) */
                } else {
  mmap_failed:
                        while ((nr = read(from_fd, buf, sizeof(buf))) > 0) {