hush: fix read builtin to not read ahead past eol and to not use

insane amounts of stack. Testsuite updated.

10 files changed, 68 insertions, 31 deletions

diff --git a/include/libbb.h b/include/libbb.h
index ce62f4529..5aa95ea88 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -400,7 +400,11 @@ extern ssize_t safe_read(int fd, void *buf, size_t count);
 extern ssize_t full_read(int fd, void *buf, size_t count);
 extern void xread(int fd, void *buf, size_t count);
 extern unsigned char xread_char(int fd);
+// Read one line a-la fgets. Uses one read(), works only on seekable streams
 extern char *reads(int fd, char *buf, size_t count);
+// Read one line a-la fgets. Reads byte-by-byte.
+// Useful when it is important to not read ahead.
+extern char *xmalloc_reads(int fd, char *pfx);
 extern ssize_t read_close(int fd, void *buf, size_t count);
 extern ssize_t open_read_close(const char *filename, void *buf, size_t count);
 extern void *xmalloc_open_read_close(const char *filename, size_t *sizep);
diff --git a/libbb/read.c b/libbb/read.c
index c05b26b50..05bf754e0 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -38,10 +38,8 @@ ssize_t full_read(int fd, void *buf, size_t len)
 
                 if (cc < 0)
                         return cc;      /* read() returns -1 on failure. */
-
                 if (cc == 0)
                         break;
-
                 buf = ((char *)buf) + cc;
                 total += cc;
                 len -= cc;
@@ -64,9 +62,7 @@ void xread(int fd, void *buf, size_t count)
 unsigned char xread_char(int fd)
 {
         char tmp;
-
         xread(fd, &tmp, 1);
-
         return tmp;
 }
 
@@ -95,6 +91,37 @@ char *reads(int fd, char *buffer, size_t size)
         return buffer;
 }
 
+// Read one line a-la fgets. Reads byte-by-byte.
+// Useful when it is important to not read ahead.
+char *xmalloc_reads(int fd, char *buf)
+{
+        char *p;
+        int sz = buf ? strlen(buf) : 0;
+
+        goto jump_in;
+        while (1) {
+                if (p - buf == sz) {
+ jump_in:
+                        buf = xrealloc(buf, sz + 128);
+                        p = buf + sz;
+                        sz += 128;
+                }
+                if (safe_read(fd, p, 1) != 1) { /* EOF/error */
+                        if (p == buf) {
+                                /* we read nothing [and buf was NULL initially] */
+                                free(buf);
+                                return NULL;
+                        }
+                        break;
+                }
+                if (*p == '\n')
+                        break;
+                p++;
+        }
+        *p++ = '\0';
+        return xrealloc(buf, p - buf);
+}
+
 ssize_t read_close(int fd, void *buf, size_t size)
 {
         int e;
@@ -113,25 +140,29 @@ ssize_t open_read_close(const char *filename, void *buf, size_t size)
         return read_close(fd, buf, size);
 }
 
+// Read (potentially big) files in one go. File size is estimated by
+// lseek to end.
 void *xmalloc_open_read_close(const char *filename, size_t *sizep)
 {
         char *buf;
         size_t size = sizep ? *sizep : INT_MAX;
-        int fd = xopen(filename, O_RDONLY);
+        int fd;
+        off_t len;
+
+        fd = xopen(filename, O_RDONLY);
         /* /proc/N/stat files report len 0 here */
         /* In order to make such files readable, we add small const */
-        off_t len = xlseek(fd, 0, SEEK_END) + 256;
+        len = xlseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
         xlseek(fd, 0, SEEK_SET);
-
-        if (len > size)
-                bb_error_msg_and_die("file '%s' is too big", filename);
-        size = len;
+        if (len < size)
+                size = len;
         buf = xmalloc(size + 1);
         size = read_close(fd, buf, size);
         if ((ssize_t)size < 0)
                 bb_perror_msg_and_die("'%s'", filename);
         xrealloc(buf, size + 1);
         buf[size] = '\0';
-        if (sizep) *sizep = size;
+        if (sizep)
+                *sizep = size;
         return buf;
 }
diff --git a/modutils/insmod.c b/modutils/insmod.c
index a81ca7fba..b9d8a0243 100644
--- a/modutils/insmod.c
+++ b/modutils/insmod.c
@@ -4262,6 +4262,7 @@ int insmod_ng_main(int argc, char **argv)
 {
         long ret;
         size_t len;
+        int optlen;
         void *map;
         char *filename, *options;
 
@@ -4270,12 +4271,12 @@ int insmod_ng_main(int argc, char **argv)
                 bb_show_usage();
 
         /* Rest is options */
-        options = xstrdup("");
+        options = xzalloc(1);
+        optlen = 0;
         while (*++argv) {
-                int optlen = strlen(options);
                 options = xrealloc(options, optlen + 2 + strlen(*argv) + 2);
                 /* Spaces handled by "" pairs, but no way of escaping quotes */
-                sprintf(options + optlen, (strchr(*argv,' ') ? "\"%s\" " : "%s "), *argv);
+                optlen += sprintf(options + optlen, (strchr(*argv,' ') ? "\"%s\" " : "%s "), *argv);
         }
 
 #if 0
diff --git a/modutils/modprobe.c b/modutils/modprobe.c
index a7c6307f8..dbed4ea0f 100644
--- a/modutils/modprobe.c
+++ b/modutils/modprobe.c
@@ -234,7 +234,7 @@ static void include_conf(struct dep_t **first, struct dep_t **current, char *buf
 {
         int continuation_line = 0;
 
-        // alias parsing is not 100% correct (no correct handling of continuation lines within an alias) !
+        // alias parsing is not 100% correct (no correct handling of continuation lines within an alias)!
 
         while (reads(fd, buffer, buflen)) {
                 int l;
diff --git a/shell/README b/shell/README
index a09353d6c..b86f96cf4 100644
--- a/shell/README
+++ b/shell/README
@@ -1,5 +1,8 @@
 Various bits of what is known about busybox shells, in no particular order.
 
+2007-06-13
+hush: exec <"$1" doesn't do parameter subst
+
 2007-05-24
 hush: environment-related memory leak plugged, with net code size
 decrease.
diff --git a/shell/ash.c b/shell/ash.c
index ae078e609..173beb195 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -11567,8 +11567,8 @@ readcmd(int argc, char **argv)
 #endif
 #if ENABLE_ASH_READ_TIMEOUT
         if (ts.tv_sec || ts.tv_usec) {
-                FD_ZERO (&set);
-                FD_SET (0, &set);
+                FD_ZERO(&set);
+                FD_SET(0, &set);
 
                 i = select(FD_SETSIZE, &set, NULL, NULL, &ts);
                 if (!i) {
diff --git a/shell/hush.c b/shell/hush.c
index 40bcafdd9..e6fa3d9a5 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -942,21 +942,11 @@ static int builtin_pwd(char **argv ATTRIBUTE_UNUSED)
 /* built-in 'read VAR' handler */
 static int builtin_read(char **argv)
 {
-        char string[BUFSIZ];
-        char *p;
+        char *string;
         const char *name = argv[1] ? argv[1] : "REPLY";
-        int name_len = strlen(name);
 
-        if (name_len >= sizeof(string) - 2)
-                return EXIT_FAILURE;
-        strcpy(string, name);
-        p = string + name_len;
-        *p++ = '=';
-        *p = '\0'; /* In case stdin has only EOF */
-        /* read string. name_len+1 chars are already used by 'name=' */
-        fgets(p, sizeof(string) - 1 - name_len, stdin);
-        chomp(p);
-        return set_local_var(xstrdup(string), 0);
+        string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name));
+        return set_local_var(string, 0);
 }
 
 /* built-in 'set [VAR=value]' handler */
diff --git a/shell/hush_test/hush-misc/read.right b/shell/hush_test/hush-misc/read.right
new file mode 100644
index 000000000..0e50e2a23
--- /dev/null
+++ b/shell/hush_test/hush-misc/read.right
@@ -0,0 +1,4 @@
+read
+cat
+echo "REPLY=$REPLY"
+REPLY=exec <read.tests
diff --git a/shell/hush_test/hush-misc/read.tests b/shell/hush_test/hush-misc/read.tests
new file mode 100755
index 000000000..ff1acbde1
--- /dev/null
+++ b/shell/hush_test/hush-misc/read.tests
@@ -0,0 +1,4 @@
+exec <read.tests
+read
+cat
+echo "REPLY=$REPLY"
diff --git a/util-linux/readprofile.c b/util-linux/readprofile.c
index f2bd3bbae..02afedcf0 100644
--- a/util-linux/readprofile.c
+++ b/util-linux/readprofile.c
@@ -99,7 +99,7 @@ int readprofile_main(int argc, char **argv)
         /*
          * Use an fd for the profiling buffer, to skip stdio overhead
          */
-        len = INT_MAX;
+        len = MAXINT(ssize_t);
         buf = xmalloc_open_read_close(proFile, &len);
         if (!optNative) {
                 int entries = len/sizeof(*buf);