libbb: prevent xmalloc_open_read_close from dying on seek failure

start_stop_daemon: use open_read_close instead of xmalloc_open_read_close
start_stop_daemon: use local structure instead of global one

function                                             old     new   delta
check                                               1620    1661     +41
xmalloc_open_read_close                              171     190     +19
start_stop_daemon_main                               976     954     -22
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 60/-22)             Total: 38 bytes

diff --git a/debianutils/start_stop_daemon.c b/debianutils/start_stop_daemon.c
index c5c4059..9150763 100644 (file)
--- a/debianutils/start_stop_daemon.c
+++ b/debianutils/start_stop_daemon.c
@@ -32,7 +32,6 @@ struct globals {
        int user_id;
        smallint quiet;
        smallint signal_nr;
-       struct stat execstat;
 };
 #define G (*(struct globals*)&bb_common_bufsiz1)
 #define found             (G.found               )
@@ -43,7 +42,6 @@ struct globals {
 #define user_id           (G.user_id             )
 #define quiet             (G.quiet               )
 #define signal_nr         (G.signal_nr           )
-#define execstat          (G.execstat            )
 #define INIT_G() \
         do { \
                user_id = -1; \
@@ -53,12 +51,13 @@ struct globals {
 
 static int pid_is_exec(pid_t pid)
 {
-       struct stat st;
+       struct stat st, execstat;
        char buf[sizeof("/proc//exe") + sizeof(int)*3];
 
        sprintf(buf, "/proc/%u/exe", pid);
        if (stat(buf, &st) < 0)
                return 0;
+       xstat(execname, &execstat);
        if (st.st_dev == execstat.st_dev
         && st.st_ino == execstat.st_ino)
                return 1;
@@ -78,24 +77,21 @@ static int pid_is_user(int pid)
 
 static int pid_is_cmd(pid_t pid)
 {
-       char fname[sizeof("/proc//stat") + sizeof(int)*3];
-       char *buf;
-       int r = 0;
-
-       sprintf(fname, "/proc/%u/stat", pid);
-       buf = xmalloc_open_read_close(fname, NULL);
-       if (buf) {
-               char *p = strchr(buf, '(');
-               if (p) {
-                       char *pe = strrchr(++p, ')');
-                       if (pe) {
-                               *pe = '\0';
-                               r = !strcmp(p, cmdname);
-                       }
-               }
-               free(buf);
-       }
-       return r;
+       char buf[256]; /* is it big enough? */
+       char *p, *pe;
+
+       sprintf(buf, "/proc/%u/stat", pid);
+       if (open_read_close(buf, buf, sizeof(buf) - 1) < 0)
+               return 0;
+       buf[sizeof(buf) - 1] = '\0'; /* paranoia */
+       p = strchr(buf, '(');
+       if (!p)
+               return 0;
+       pe = strrchr(++p, ')');
+       if (!pe)
+               return 0;
+       *pe = '\0';
+       return !strcmp(p, cmdname);
 }
 
 static void check(int pid)
@@ -303,8 +299,6 @@ int start_stop_daemon_main(int argc ATTRIBUTE_UNUSED, char **argv)
                if (errno)
                        user_id = xuname2uid(userspec);
        }
-       if (execname)
-               xstat(execname, &execstat);
 
        do_procinit(); /* Both start and stop needs to know current processes */
 

diff --git a/libbb/read.c b/libbb/read.c
index ba366cb..e5f140f 100644 (file)
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -208,25 +208,34 @@ ssize_t open_read_close(const char *filename, void *buf, size_t size)
 void *xmalloc_open_read_close(const char *filename, size_t *sizep)
 {
        char *buf;
-       size_t size = sizep ? *sizep : INT_MAX;
+       size_t size;
        int fd;
        off_t len;
 
        fd = open(filename, O_RDONLY);
        if (fd < 0)
                return NULL;
+
        /* /proc/N/stat files report len 0 here */
        /* In order to make such files readable, we add small const */
-       len = xlseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
-       xlseek(fd, 0, SEEK_SET);
-       if (len < size)
-               size = len;
+       size = 0x3ff; /* read only 1k on unseekable files */
+       len = lseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
+       if (len != (off_t)-1) {
+               xlseek(fd, 0, SEEK_SET);
+               size = sizep ? *sizep : INT_MAX;
+               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);
+       if ((ssize_t)size < 0) {
+               free(buf);
+               return NULL;
+       }
        xrealloc(buf, size + 1);
        buf[size] = '\0';
+
        if (sizep)
                *sizep = size;
        return buf;