Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML fixes from Richard Weinberger: "Assorted fixes for UML" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: um: Memory corruption on startup um: Missing pipe handling uml: Simplify tempdir logic.

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml
Pull UML fixes from Richard Weinberger: "Assorted fixes for UML" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: um: Memory corruption on startup um: Missing pipe handling uml: Simplify tempdir logic.
Linus Torvalds
2 parents 9ac0367501 0565103d1a
Showing 5 changed files Side-by-side Diff
arch/um/include/shared/os.h
arch/um/kernel/physmem.c
arch/um/os-Linux/file.c
arch/um/os-Linux/main.c
arch/um/os-Linux/mem.c
@@ -136,6 +136,7 @@
 extern int os_get_ifname(int fd, char *namebuf);
 extern int os_set_slip(int fd);
 extern int os_mode_fd(int fd, int mode);
+extern int os_fsync_file(int fd);
  
 extern int os_seek_file(int fd, unsigned long long offset);
 extern int os_open_file(const char *file, struct openflags flags, int mode);
@@ -103,6 +103,7 @@
 	 */
 	os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
 	os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
+	os_fsync_file(physmem_fd);
  
 	bootmap_size = init_bootmem(pfn, pfn + delta);
 	free_bootmem(__pa(reserve_end) + bootmap_size,
@@ -237,6 +237,12 @@
 {
 	close(fd);
 }
+int os_fsync_file(int fd)
+{
+	if (fsync(fd) < 0)
+	    return -errno;
+	return 0;
+}
  
 int os_seek_file(int fd, unsigned long long offset)
 {
@@ -151,6 +151,7 @@
 #endif
  
 	do_uml_initcalls();
+	change_sig(SIGPIPE, 0);
 	ret = linux_main(argc, argv);
  
 	/*
@@ -12,337 +12,117 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/mman.h>
-#include <sys/param.h>
+#include <sys/vfs.h>
+#include <linux/magic.h>
 #include <init.h>
 #include <os.h>
  
-/* Modified by which_tmpdir, which is called during early boot */
-static char *default_tmpdir = "/tmp";
-
-/*
- *  Modified when creating the physical memory file and when checking
- * the tmp filesystem for usability, both happening during early boot.
- */
+/* Set by make_tempfile() during early boot. */
 static char *tempdir = NULL;
  
-static void __init find_tempdir(void)
+/* Check if dir is on tmpfs. Return 0 if yes, -1 if no or error. */
+static int __init check_tmpfs(const char *dir)
 {
-	const char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL };
-	int i;
-	char *dir = NULL;
+	struct statfs st;
  
-	if (tempdir != NULL)
-		/* We've already been called */
-		return;
-	for (i = 0; dirs[i]; i++) {
-		dir = getenv(dirs[i]);
-		if ((dir != NULL) && (*dir != '\0'))
-			break;
+	printf("Checking if %s is on tmpfs...", dir);
+	if (statfs(dir, &st) < 0) {
+		printf("%s\n", strerror(errno));
+	} else if (st.f_type != TMPFS_MAGIC) {
+		printf("no\n");
+	} else {
+		printf("OK\n");
+		return 0;
 	}
-	if ((dir == NULL) || (*dir == '\0'))
-		dir = default_tmpdir;
-
-	tempdir = malloc(strlen(dir) + 2);
-	if (tempdir == NULL) {
-		fprintf(stderr, "Failed to malloc tempdir, "
-			"errno = %d\n", errno);
-		return;
-	}
-	strcpy(tempdir, dir);
-	strcat(tempdir, "/");
+	return -1;
 }
  
 /*
- * Remove bytes from the front of the buffer and refill it so that if there's a
- * partial string that we care about, it will be completed, and we can recognize
- * it.
+ * Choose the tempdir to use. We want something on tmpfs so that our memory is
+ * not subject to the host's vm.dirty_ratio. If a tempdir is specified in the
+ * environment, we use that even if it's not on tmpfs, but we warn the user.
+ * Otherwise, we try common tmpfs locations, and if no tmpfs directory is found
+ * then we fall back to /tmp.
  */
-static int pop(int fd, char *buf, size_t size, size_t npop)
+static char * __init choose_tempdir(void)
 {
-	ssize_t n;
-	size_t len = strlen(&buf[npop]);
-
-	memmove(buf, &buf[npop], len + 1);
-	n = read(fd, &buf[len], size - len - 1);
-	if (n < 0)
-		return -errno;
-
-	buf[len + n] = '\0';
-	return 1;
-}
-
-/*
- * This will return 1, with the first character in buf being the
- * character following the next instance of c in the file.  This will
- * read the file as needed.  If there's an error, -errno is returned;
- * if the end of the file is reached, 0 is returned.
- */
-static int next(int fd, char *buf, size_t size, char c)
-{
-	ssize_t n;
-	char *ptr;
-
-	while ((ptr = strchr(buf, c)) == NULL) {
-		n = read(fd, buf, size - 1);
-		if (n == 0)
-			return 0;
-		else if (n < 0)
-			return -errno;
-
-		buf[n] = '\0';
-	}
-
-	return pop(fd, buf, size, ptr - buf + 1);
-}
-
-/*
- * Decode an octal-escaped and space-terminated path of the form used by
- * /proc/mounts. May be used to decode a path in-place. "out" must be at least
- * as large as the input. The output is always null-terminated. "len" gets the
- * length of the output, excluding the trailing null. Returns 0 if a full path
- * was successfully decoded, otherwise an error.
- */
-static int decode_path(const char *in, char *out, size_t *len)
-{
-	char *first = out;
-	int c;
+	static const char * const vars[] = {
+		"TMPDIR",
+		"TMP",
+		"TEMP",
+		NULL
+	};
+	static const char fallback_dir[] = "/tmp";
+	static const char * const tmpfs_dirs[] = {
+		"/dev/shm",
+		fallback_dir,
+		NULL
+	};
 	int i;
-	int ret = -EINVAL;
-	while (1) {
-		switch (*in) {
-		case '\0':
-			goto out;
+	const char *dir;
  
-		case ' ':
-			ret = 0;
-			goto out;
-
-		case '\\':
-			in++;
-			c = 0;
-			for (i = 0; i < 3; i++) {
-				if (*in < '0' || *in > '7')
-					goto out;
-				c = (c << 3) | (*in++ - '0');
-			}
-			*(unsigned char *)out++ = (unsigned char) c;
-			break;
-
-		default:
-			*out++ = *in++;
-			break;
+	printf("Checking environment variables for a tempdir...");
+	for (i = 0; vars[i]; i++) {
+		dir = getenv(vars[i]);
+		if ((dir != NULL) && (*dir != '\0')) {
+			printf("%s\n", dir);
+			if (check_tmpfs(dir) >= 0)
+				goto done;
+			else
+				goto warn;
 		}
 	}
+	printf("none found\n");
  
-out:
-	*out = '\0';
-	*len = out - first;
-	return ret;
-}
-
-/*
- * Computes the length of s when encoded with three-digit octal escape sequences
- * for the characters in chars.
- */
-static size_t octal_encoded_length(const char *s, const char *chars)
-{
-	size_t len = strlen(s);
-	while ((s = strpbrk(s, chars)) != NULL) {
-		len += 3;
-		s++;
+	for (i = 0; tmpfs_dirs[i]; i++) {
+		dir = tmpfs_dirs[i];
+		if (check_tmpfs(dir) >= 0)
+			goto done;
 	}
  
-	return len;
+	dir = fallback_dir;
+warn:
+	printf("Warning: tempdir %s is not on tmpfs\n", dir);
+done:
+	/* Make a copy since getenv results may not remain valid forever. */
+	return strdup(dir);
 }
  
-enum {
-	OUTCOME_NOTHING_MOUNTED,
-	OUTCOME_TMPFS_MOUNT,
-	OUTCOME_NON_TMPFS_MOUNT,
-};
-
-/* Read a line of /proc/mounts data looking for a tmpfs mount at "path". */
-static int read_mount(int fd, char *buf, size_t bufsize, const char *path,
-		      int *outcome)
-{
-	int found;
-	int match;
-	char *space;
-	size_t len;
-
-	enum {
-		MATCH_NONE,
-		MATCH_EXACT,
-		MATCH_PARENT,
-	};
-
-	found = next(fd, buf, bufsize, ' ');
-	if (found != 1)
-		return found;
-
-	/*
-	 * If there's no following space in the buffer, then this path is
-	 * truncated, so it can't be the one we're looking for.
-	 */
-	space = strchr(buf, ' ');
-	if (space) {
-		match = MATCH_NONE;
-		if (!decode_path(buf, buf, &len)) {
-			if (!strcmp(buf, path))
-				match = MATCH_EXACT;
-			else if (!strncmp(buf, path, len)
-				 && (path[len] == '/' || !strcmp(buf, "/")))
-				match = MATCH_PARENT;
-		}
-
-		found = pop(fd, buf, bufsize, space - buf + 1);
-		if (found != 1)
-			return found;
-
-		switch (match) {
-		case MATCH_EXACT:
-			if (!strncmp(buf, "tmpfs", strlen("tmpfs")))
-				*outcome = OUTCOME_TMPFS_MOUNT;
-			else
-				*outcome = OUTCOME_NON_TMPFS_MOUNT;
-			break;
-
-		case MATCH_PARENT:
-			/* This mount obscures any previous ones. */
-			*outcome = OUTCOME_NOTHING_MOUNTED;
-			break;
-		}
-	}
-
-	return next(fd, buf, bufsize, '\n');
-}
-
-/* which_tmpdir is called only during early boot */
-static int checked_tmpdir = 0;
-
 /*
- * Look for a tmpfs mounted at /dev/shm.  I couldn't find a cleaner
- * way to do this than to parse /proc/mounts.  statfs will return the
- * same filesystem magic number and fs id for both /dev and /dev/shm
- * when they are both tmpfs, so you can't tell if they are different
- * filesystems.  Also, there seems to be no other way of finding the
- * mount point of a filesystem from within it.
- *
- * If a /dev/shm tmpfs entry is found, then we switch to using it.
- * Otherwise, we stay with the default /tmp.
+ * Create an unlinked tempfile in a suitable tempdir. template must be the
+ * basename part of the template with a leading '/'.
  */
-static void which_tmpdir(void)
+static int __init make_tempfile(const char *template)
 {
+	char *tempname;
 	int fd;
-	int found;
-	int outcome;
-	char *path;
-	char *buf;
-	size_t bufsize;
  
-	if (checked_tmpdir)
-		return;
-
-	checked_tmpdir = 1;
-
-	printf("Checking for tmpfs mount on /dev/shm...");
-
-	path = realpath("/dev/shm", NULL);
-	if (!path) {
-		printf("failed to check real path, errno = %d\n", errno);
-		return;
-	}
-	printf("%s...", path);
-
-	/*
-	 * The buffer needs to be able to fit the full octal-escaped path, a
-	 * space, and a trailing null in order to successfully decode it.
-	 */
-	bufsize = octal_encoded_length(path, " \t\n\\") + 2;
-
-	if (bufsize < 128)
-		bufsize = 128;
-
-	buf = malloc(bufsize);
-	if (!buf) {
-		printf("malloc failed, errno = %d\n", errno);
-		goto out;
-	}
-	buf[0] = '\0';
-
-	fd = open("/proc/mounts", O_RDONLY);
-	if (fd < 0) {
-		printf("failed to open /proc/mounts, errno = %d\n", errno);
-		goto out1;
-	}
-
-	outcome = OUTCOME_NOTHING_MOUNTED;
-	while (1) {
-		found = read_mount(fd, buf, bufsize, path, &outcome);
-		if (found != 1)
-			break;
-	}
-
-	if (found < 0) {
-		printf("read returned errno %d\n", -found);
-	} else {
-		switch (outcome) {
-		case OUTCOME_TMPFS_MOUNT:
-			printf("OK\n");
-			default_tmpdir = "/dev/shm";
-			break;
-
-		case OUTCOME_NON_TMPFS_MOUNT:
-			printf("not tmpfs\n");
-			break;
-
-		default:
-			printf("nothing mounted on /dev/shm\n");
-			break;
+	if (tempdir == NULL) {
+		tempdir = choose_tempdir();
+		if (tempdir == NULL) {
+			fprintf(stderr, "Failed to choose tempdir: %s\n",
+				strerror(errno));
+			return -1;
 		}
 	}
  
-	close(fd);
-out1:
-	free(buf);
-out:
-	free(path);
-}
-
-static int __init make_tempfile(const char *template, char **out_tempname,
-				int do_unlink)
-{
-	char *tempname;
-	int fd;
-
-	which_tmpdir();
-	tempname = malloc(MAXPATHLEN);
+	tempname = malloc(strlen(tempdir) + strlen(template) + 1);
 	if (tempname == NULL)
 		return -1;
  
-	find_tempdir();
-	if ((tempdir == NULL) || (strlen(tempdir) >= MAXPATHLEN))
-		goto out;
-
-	if (template[0] != '/')
-		strcpy(tempname, tempdir);
-	else
-		tempname[0] = '\0';
-	strncat(tempname, template, MAXPATHLEN-1-strlen(tempname));
+	strcpy(tempname, tempdir);
+	strcat(tempname, template);
 	fd = mkstemp(tempname);
 	if (fd < 0) {
 		fprintf(stderr, "open - cannot create %s: %s\n", tempname,
 			strerror(errno));
 		goto out;
 	}
-	if (do_unlink && (unlink(tempname) < 0)) {
+	if (unlink(tempname) < 0) {
 		perror("unlink");
 		goto close;
 	}
-	if (out_tempname) {
-		*out_tempname = tempname;
-	} else
-		free(tempname);
+	free(tempname);
 	return fd;
 close:
 	close(fd);
  
@@ -351,14 +131,14 @@
 	return -1;
 }
  
-#define TEMPNAME_TEMPLATE "vm_file-XXXXXX"
+#define TEMPNAME_TEMPLATE "/vm_file-XXXXXX"
  
 static int __init create_tmp_file(unsigned long long len)
 {
 	int fd, err;
 	char zero;
  
-	fd = make_tempfile(TEMPNAME_TEMPLATE, NULL, 1);
+	fd = make_tempfile(TEMPNAME_TEMPLATE);
 	if (fd < 0)
 		exit(1);
  
@@ -402,7 +182,6 @@
 	return fd;
 }
  
-
 void __init check_tmpexec(void)
 {
 	void *addr;
  
  
@@ -410,14 +189,13 @@
  
 	addr = mmap(NULL, UM_KERN_PAGE_SIZE,
 		    PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
-	printf("Checking PROT_EXEC mmap in %s...",tempdir);
-	fflush(stdout);
+	printf("Checking PROT_EXEC mmap in %s...", tempdir);
 	if (addr == MAP_FAILED) {
 		err = errno;
-		perror("failed");
+		printf("%s\n", strerror(err));
 		close(fd);
 		if (err == EPERM)
-			printf("%s must be not mounted noexec\n",tempdir);
+			printf("%s must be not mounted noexec\n", tempdir);
 		exit(1);
 	}
 	printf("OK\n");
...	...	@@ -136,6 +136,7 @@
136	136	extern int os_get_ifname(int fd, char *namebuf);
137	137	extern int os_set_slip(int fd);
138	138	extern int os_mode_fd(int fd, int mode);
	139	+extern int os_fsync_file(int fd);
139	140
140	141	extern int os_seek_file(int fd, unsigned long long offset);
141	142	extern int os_open_file(const char *file, struct openflags flags, int mode);
...	...	@@ -103,6 +103,7 @@
103	103	*/
104	104	os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
105	105	os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
	106	+ os_fsync_file(physmem_fd);
106	107
107	108	bootmap_size = init_bootmem(pfn, pfn + delta);
108	109	free_bootmem(__pa(reserve_end) + bootmap_size,
...	...	@@ -237,6 +237,12 @@
237	237	{
238	238	close(fd);
239	239	}
	240	+int os_fsync_file(int fd)
	241	+{
	242	+ if (fsync(fd) < 0)
	243	+ return -errno;
	244	+ return 0;
	245	+}
240	246
241	247	int os_seek_file(int fd, unsigned long long offset)
242	248	{
...	...	@@ -151,6 +151,7 @@
151	151	#endif
152	152
153	153	do_uml_initcalls();
	154	+ change_sig(SIGPIPE, 0);
154	155	ret = linux_main(argc, argv);
155	156
156	157	/*
...	...	@@ -12,337 +12,117 @@
12	12	#include <string.h>
13	13	#include <sys/stat.h>
14	14	#include <sys/mman.h>
15		-#include <sys/param.h>
	15	+#include <sys/vfs.h>
	16	+#include <linux/magic.h>
16	17	#include <init.h>
17	18	#include <os.h>
18	19
19		-/* Modified by which_tmpdir, which is called during early boot */
20		-static char *default_tmpdir = "/tmp";
21		-
22		-/*
23		- * Modified when creating the physical memory file and when checking
24		- * the tmp filesystem for usability, both happening during early boot.
25		- */
	20	+/* Set by make_tempfile() during early boot. */
26	21	static char *tempdir = NULL;
27	22
28		-static void __init find_tempdir(void)
	23	+/* Check if dir is on tmpfs. Return 0 if yes, -1 if no or error. */
	24	+static int __init check_tmpfs(const char *dir)
29	25	{
30		- const char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL };
31		- int i;
32		- char *dir = NULL;
	26	+ struct statfs st;
33	27
34		- if (tempdir != NULL)
35		- /* We've already been called */
36		- return;
37		- for (i = 0; dirs[i]; i++) {
38		- dir = getenv(dirs[i]);
39		- if ((dir != NULL) && (*dir != '\0'))
40		- break;
	28	+ printf("Checking if %s is on tmpfs...", dir);
	29	+ if (statfs(dir, &st) < 0) {
	30	+ printf("%s\n", strerror(errno));
	31	+ } else if (st.f_type != TMPFS_MAGIC) {
	32	+ printf("no\n");
	33	+ } else {
	34	+ printf("OK\n");
	35	+ return 0;
41	36	}
42		- if ((dir == NULL) \|\| (*dir == '\0'))
43		- dir = default_tmpdir;
44		-
45		- tempdir = malloc(strlen(dir) + 2);
46		- if (tempdir == NULL) {
47		- fprintf(stderr, "Failed to malloc tempdir, "
48		- "errno = %d\n", errno);
49		- return;
50		- }
51		- strcpy(tempdir, dir);
52		- strcat(tempdir, "/");
	37	+ return -1;
53	38	}
54	39
55	40	/*
56		- * Remove bytes from the front of the buffer and refill it so that if there's a
57		- * partial string that we care about, it will be completed, and we can recognize
58		- * it.
	41	+ * Choose the tempdir to use. We want something on tmpfs so that our memory is
	42	+ * not subject to the host's vm.dirty_ratio. If a tempdir is specified in the
	43	+ * environment, we use that even if it's not on tmpfs, but we warn the user.
	44	+ * Otherwise, we try common tmpfs locations, and if no tmpfs directory is found
	45	+ * then we fall back to /tmp.
59	46	*/
60		-static int pop(int fd, char *buf, size_t size, size_t npop)
	47	+static char * __init choose_tempdir(void)
61	48	{
62		- ssize_t n;
63		- size_t len = strlen(&buf[npop]);
64		-
65		- memmove(buf, &buf[npop], len + 1);
66		- n = read(fd, &buf[len], size - len - 1);
67		- if (n < 0)
68		- return -errno;
69		-
70		- buf[len + n] = '\0';
71		- return 1;
72		-}
73		-
74		-/*
75		- * This will return 1, with the first character in buf being the
76		- * character following the next instance of c in the file. This will
77		- * read the file as needed. If there's an error, -errno is returned;
78		- * if the end of the file is reached, 0 is returned.
79		- */
80		-static int next(int fd, char *buf, size_t size, char c)
81		-{
82		- ssize_t n;
83		- char *ptr;
84		-
85		- while ((ptr = strchr(buf, c)) == NULL) {
86		- n = read(fd, buf, size - 1);
87		- if (n == 0)
88		- return 0;
89		- else if (n < 0)
90		- return -errno;
91		-
92		- buf[n] = '\0';
93		- }
94		-
95		- return pop(fd, buf, size, ptr - buf + 1);
96		-}
97		-
98		-/*
99		- * Decode an octal-escaped and space-terminated path of the form used by
100		- * /proc/mounts. May be used to decode a path in-place. "out" must be at least
101		- * as large as the input. The output is always null-terminated. "len" gets the
102		- * length of the output, excluding the trailing null. Returns 0 if a full path
103		- * was successfully decoded, otherwise an error.
104		- */
105		-static int decode_path(const char in, char out, size_t *len)
106		-{
107		- char *first = out;
108		- int c;
	49	+ static const char * const vars[] = {
	50	+ "TMPDIR",
	51	+ "TMP",
	52	+ "TEMP",
	53	+ NULL
	54	+ };
	55	+ static const char fallback_dir[] = "/tmp";
	56	+ static const char * const tmpfs_dirs[] = {
	57	+ "/dev/shm",
	58	+ fallback_dir,
	59	+ NULL
	60	+ };
109	61	int i;
110		- int ret = -EINVAL;
111		- while (1) {
112		- switch (*in) {
113		- case '\0':
114		- goto out;
	62	+ const char *dir;
115	63
116		- case ' ':
117		- ret = 0;
118		- goto out;
119		-
120		- case '\\':
121		- in++;
122		- c = 0;
123		- for (i = 0; i < 3; i++) {
124		- if (in < '0' \|\| in > '7')
125		- goto out;
126		- c = (c << 3) \| (*in++ - '0');
127		- }
128		- (unsigned char )out++ = (unsigned char) c;
129		- break;
130		-
131		- default:
132		- out++ = in++;
133		- break;
	64	+ printf("Checking environment variables for a tempdir...");
	65	+ for (i = 0; vars[i]; i++) {
	66	+ dir = getenv(vars[i]);
	67	+ if ((dir != NULL) && (*dir != '\0')) {
	68	+ printf("%s\n", dir);
	69	+ if (check_tmpfs(dir) >= 0)
	70	+ goto done;
	71	+ else
	72	+ goto warn;
134	73	}
135	74	}
	75	+ printf("none found\n");
136	76
137		-out:
138		- *out = '\0';
139		- *len = out - first;
140		- return ret;
141		-}
142		-
143		-/*
144		- * Computes the length of s when encoded with three-digit octal escape sequences
145		- * for the characters in chars.
146		- */
147		-static size_t octal_encoded_length(const char s, const char chars)
148		-{
149		- size_t len = strlen(s);
150		- while ((s = strpbrk(s, chars)) != NULL) {
151		- len += 3;
152		- s++;
	77	+ for (i = 0; tmpfs_dirs[i]; i++) {
	78	+ dir = tmpfs_dirs[i];
	79	+ if (check_tmpfs(dir) >= 0)
	80	+ goto done;
153	81	}
154	82
155		- return len;
	83	+ dir = fallback_dir;
	84	+warn:
	85	+ printf("Warning: tempdir %s is not on tmpfs\n", dir);
	86	+done:
	87	+ /* Make a copy since getenv results may not remain valid forever. */
	88	+ return strdup(dir);
156	89	}
157	90
158		-enum {
159		- OUTCOME_NOTHING_MOUNTED,
160		- OUTCOME_TMPFS_MOUNT,
161		- OUTCOME_NON_TMPFS_MOUNT,
162		-};
163		-
164		-/* Read a line of /proc/mounts data looking for a tmpfs mount at "path". */
165		-static int read_mount(int fd, char buf, size_t bufsize, const char path,
166		- int *outcome)
167		-{
168		- int found;
169		- int match;
170		- char *space;
171		- size_t len;
172		-
173		- enum {
174		- MATCH_NONE,
175		- MATCH_EXACT,
176		- MATCH_PARENT,
177		- };
178		-
179		- found = next(fd, buf, bufsize, ' ');
180		- if (found != 1)
181		- return found;
182		-
183		- /*
184		- * If there's no following space in the buffer, then this path is
185		- * truncated, so it can't be the one we're looking for.
186		- */
187		- space = strchr(buf, ' ');
188		- if (space) {
189		- match = MATCH_NONE;
190		- if (!decode_path(buf, buf, &len)) {
191		- if (!strcmp(buf, path))
192		- match = MATCH_EXACT;
193		- else if (!strncmp(buf, path, len)
194		- && (path[len] == '/' \|\| !strcmp(buf, "/")))
195		- match = MATCH_PARENT;
196		- }
197		-
198		- found = pop(fd, buf, bufsize, space - buf + 1);
199		- if (found != 1)
200		- return found;
201		-
202		- switch (match) {
203		- case MATCH_EXACT:
204		- if (!strncmp(buf, "tmpfs", strlen("tmpfs")))
205		- *outcome = OUTCOME_TMPFS_MOUNT;
206		- else
207		- *outcome = OUTCOME_NON_TMPFS_MOUNT;
208		- break;
209		-
210		- case MATCH_PARENT:
211		- /* This mount obscures any previous ones. */
212		- *outcome = OUTCOME_NOTHING_MOUNTED;
213		- break;
214		- }
215		- }
216		-
217		- return next(fd, buf, bufsize, '\n');
218		-}
219		-
220		-/* which_tmpdir is called only during early boot */
221		-static int checked_tmpdir = 0;
222		-
223	91	/*
224		- * Look for a tmpfs mounted at /dev/shm. I couldn't find a cleaner
225		- * way to do this than to parse /proc/mounts. statfs will return the
226		- * same filesystem magic number and fs id for both /dev and /dev/shm
227		- * when they are both tmpfs, so you can't tell if they are different
228		- * filesystems. Also, there seems to be no other way of finding the
229		- * mount point of a filesystem from within it.
230		- *
231		- * If a /dev/shm tmpfs entry is found, then we switch to using it.
232		- * Otherwise, we stay with the default /tmp.
	92	+ * Create an unlinked tempfile in a suitable tempdir. template must be the
	93	+ * basename part of the template with a leading '/'.
233	94	*/
234		-static void which_tmpdir(void)
	95	+static int __init make_tempfile(const char *template)
235	96	{
	97	+ char *tempname;
236	98	int fd;
237		- int found;
238		- int outcome;
239		- char *path;
240		- char *buf;
241		- size_t bufsize;
242	99
243		- if (checked_tmpdir)
244		- return;
245		-
246		- checked_tmpdir = 1;
247		-
248		- printf("Checking for tmpfs mount on /dev/shm...");
249		-
250		- path = realpath("/dev/shm", NULL);
251		- if (!path) {
252		- printf("failed to check real path, errno = %d\n", errno);
253		- return;
254		- }
255		- printf("%s...", path);
256		-
257		- /*
258		- * The buffer needs to be able to fit the full octal-escaped path, a
259		- * space, and a trailing null in order to successfully decode it.
260		- */
261		- bufsize = octal_encoded_length(path, " \t\n\\") + 2;
262		-
263		- if (bufsize < 128)
264		- bufsize = 128;
265		-
266		- buf = malloc(bufsize);
267		- if (!buf) {
268		- printf("malloc failed, errno = %d\n", errno);
269		- goto out;
270		- }
271		- buf[0] = '\0';
272		-
273		- fd = open("/proc/mounts", O_RDONLY);
274		- if (fd < 0) {
275		- printf("failed to open /proc/mounts, errno = %d\n", errno);
276		- goto out1;
277		- }
278		-
279		- outcome = OUTCOME_NOTHING_MOUNTED;
280		- while (1) {
281		- found = read_mount(fd, buf, bufsize, path, &outcome);
282		- if (found != 1)
283		- break;
284		- }
285		-
286		- if (found < 0) {
287		- printf("read returned errno %d\n", -found);
288		- } else {
289		- switch (outcome) {
290		- case OUTCOME_TMPFS_MOUNT:
291		- printf("OK\n");
292		- default_tmpdir = "/dev/shm";
293		- break;
294		-
295		- case OUTCOME_NON_TMPFS_MOUNT:
296		- printf("not tmpfs\n");
297		- break;
298		-
299		- default:
300		- printf("nothing mounted on /dev/shm\n");
301		- break;
	100	+ if (tempdir == NULL) {
	101	+ tempdir = choose_tempdir();
	102	+ if (tempdir == NULL) {
	103	+ fprintf(stderr, "Failed to choose tempdir: %s\n",
	104	+ strerror(errno));
	105	+ return -1;
302	106	}
303	107	}
304	108
305		- close(fd);
306		-out1:
307		- free(buf);
308		-out:
309		- free(path);
310		-}
311		-
312		-static int __init make_tempfile(const char template, char *out_tempname,
313		- int do_unlink)
314		-{
315		- char *tempname;
316		- int fd;
317		-
318		- which_tmpdir();
319		- tempname = malloc(MAXPATHLEN);
	109	+ tempname = malloc(strlen(tempdir) + strlen(template) + 1);
320	110	if (tempname == NULL)
321	111	return -1;
322	112
323		- find_tempdir();
324		- if ((tempdir == NULL) \|\| (strlen(tempdir) >= MAXPATHLEN))
325		- goto out;
326		-
327		- if (template[0] != '/')
328		- strcpy(tempname, tempdir);
329		- else
330		- tempname[0] = '\0';
331		- strncat(tempname, template, MAXPATHLEN-1-strlen(tempname));
	113	+ strcpy(tempname, tempdir);
	114	+ strcat(tempname, template);
332	115	fd = mkstemp(tempname);
333	116	if (fd < 0) {
334	117	fprintf(stderr, "open - cannot create %s: %s\n", tempname,
335	118	strerror(errno));
336	119	goto out;
337	120	}
338		- if (do_unlink && (unlink(tempname) < 0)) {
	121	+ if (unlink(tempname) < 0) {
339	122	perror("unlink");
340	123	goto close;
341	124	}
342		- if (out_tempname) {
343		- *out_tempname = tempname;
344		- } else
345		- free(tempname);
	125	+ free(tempname);
346	126	return fd;
347	127	close:
348	128	close(fd);
349	129
...	...	@@ -351,14 +131,14 @@
351	131	return -1;
352	132	}
353	133
354		-#define TEMPNAME_TEMPLATE "vm_file-XXXXXX"
	134	+#define TEMPNAME_TEMPLATE "/vm_file-XXXXXX"
355	135
356	136	static int __init create_tmp_file(unsigned long long len)
357	137	{
358	138	int fd, err;
359	139	char zero;
360	140
361		- fd = make_tempfile(TEMPNAME_TEMPLATE, NULL, 1);
	141	+ fd = make_tempfile(TEMPNAME_TEMPLATE);
362	142	if (fd < 0)
363	143	exit(1);
364	144
...	...	@@ -402,7 +182,6 @@
402	182	return fd;
403	183	}
404	184
405		-
406	185	void __init check_tmpexec(void)
407	186	{
408	187	void *addr;
409	188
410	189
...	...	@@ -410,14 +189,13 @@
410	189
411	190	addr = mmap(NULL, UM_KERN_PAGE_SIZE,
412	191	PROT_READ \| PROT_WRITE \| PROT_EXEC, MAP_PRIVATE, fd, 0);
413		- printf("Checking PROT_EXEC mmap in %s...",tempdir);
414		- fflush(stdout);
	192	+ printf("Checking PROT_EXEC mmap in %s...", tempdir);
415	193	if (addr == MAP_FAILED) {
416	194	err = errno;
417		- perror("failed");
	195	+ printf("%s\n", strerror(err));
418	196	close(fd);
419	197	if (err == EPERM)
420		- printf("%s must be not mounted noexec\n",tempdir);
	198	+ printf("%s must be not mounted noexec\n", tempdir);
421	199	exit(1);
422	200	}
423	201	printf("OK\n");