linux: turn on -Wextra

This is a followup to an earlier change (r38266) which did most of the
warning-related cleanup.  This one just flips the flag, and fixes some
new warnings that crept in during the window while the flag was off.

Second try, now with some libpng fixes.

BUG=34160

Review URL: http://codereview.chromium.org/1320011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@42700 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 16 insertions, 14 deletions

diff --git a/sandbox/linux/suid/linux_util.c b/sandbox/linux/suid/linux_util.c
index ded545b..c5af0d0 100644
--- a/sandbox/linux/suid/linux_util.c
+++ b/sandbox/linux/suid/linux_util.c
@@ -83,8 +83,9 @@ bool FindProcessHoldingSocket(pid_t* pid_out, ino_t socket_inode) {
       continue;
 
     while ((dent = readdir(fd))) {
-      if (snprintf(buf, sizeof(buf), "/proc/%lu/fd/%s", pid_ul,
-                   dent->d_name) >= sizeof(buf) - 1) {
+      int printed = snprintf(buf, sizeof(buf), "/proc/%lu/fd/%s", pid_ul,
+                             dent->d_name);
+      if (printed < 0 || printed >= (int)(sizeof(buf) - 1)) {
         continue;
       }
 
diff --git a/sandbox/linux/suid/process_util_linux.c b/sandbox/linux/suid/process_util_linux.c
index 9f40f39..7b31274 100644
--- a/sandbox/linux/suid/process_util_linux.c
+++ b/sandbox/linux/suid/process_util_linux.c
@@ -38,7 +38,7 @@ bool AdjustOOMScore(pid_t process, int score) {
 
   char buf[3];  // 0 <= |score| <= 15;
   snprintf(buf, sizeof(buf), "%d", score);
-  size_t len = strlen(buf);
+  ssize_t len = strlen(buf);
 
   ssize_t bytes_written = write(fd, buf, len);
   close(fd);
diff --git a/sandbox/linux/suid/sandbox.c b/sandbox/linux/suid/sandbox.c
index e4968c9..7389f03 100644
--- a/sandbox/linux/suid/sandbox.c
+++ b/sandbox/linux/suid/sandbox.c
@@ -90,13 +90,13 @@ static int CloneChrootHelperProcess() {
   char tempDirectoryTemplate[80] = "/tmp/chrome-sandbox-chroot-XXXXXX";
   struct statfs sfs;
   if (!statfs("/tmp", &sfs) &&
-      sfs.f_type != BTRFS_SUPER_MAGIC &&
-      sfs.f_type != EXT2_SUPER_MAGIC &&
-      sfs.f_type != EXT3_SUPER_MAGIC &&
-      sfs.f_type != EXT4_SUPER_MAGIC &&
-      sfs.f_type != REISERFS_SUPER_MAGIC &&
-      sfs.f_type != TMPFS_MAGIC &&
-      sfs.f_type != XFS_SUPER_MAGIC) {
+      (unsigned long)sfs.f_type != BTRFS_SUPER_MAGIC &&
+      (unsigned long)sfs.f_type != EXT2_SUPER_MAGIC &&
+      (unsigned long)sfs.f_type != EXT3_SUPER_MAGIC &&
+      (unsigned long)sfs.f_type != EXT4_SUPER_MAGIC &&
+      (unsigned long)sfs.f_type != REISERFS_SUPER_MAGIC &&
+      (unsigned long)sfs.f_type != TMPFS_MAGIC &&
+      (unsigned long)sfs.f_type != XFS_SUPER_MAGIC) {
     // If /dev/shm exists, it is supposed to be a tmpfs filesystem. While we
     // are not actually using it for shared memory, moving our temp directory
     // into a known tmpfs filesystem is preferable over using a potentially
@@ -137,7 +137,7 @@ static int CloneChrootHelperProcess() {
   char proc_self_fd_str[128];
   int printed = snprintf(proc_self_fd_str, sizeof(proc_self_fd_str),
                          "/proc/self/fd/%d", chroot_dir_fd);
-  if (printed < 0 || printed >= sizeof(proc_self_fd_str)) {
+  if (printed < 0 || printed >= (int)sizeof(proc_self_fd_str)) {
     fprintf(stderr, "Error in snprintf");
     return -1;
   }
@@ -246,7 +246,7 @@ static bool SpawnChrootHelper() {
   // number of the file descriptor.
   char desc_str[64];
   int printed = snprintf(desc_str, sizeof(desc_str), "%d", chroot_signal_fd);
-  if (printed < 0 || printed >= sizeof(desc_str)) {
+  if (printed < 0 || printed >= (int)sizeof(desc_str)) {
     fprintf(stderr, "Failed to snprintf\n");
     return false;
   }
@@ -379,9 +379,10 @@ int main(int argc, char **argv) {
   if (argc == 4 && (0 == strcmp(argv[1], kAdjustOOMScoreSwitch))) {
     char* endptr;
     long score;
-    pid_t pid = strtoul(argv[2], &endptr, 10);
-    if (pid == ULONG_MAX || *endptr)
+    unsigned long pid_ul = strtoul(argv[2], &endptr, 10);
+    if (pid_ul == ULONG_MAX || *endptr)
       return 1;
+    pid_t pid = pid_ul;
     score = strtol(argv[3], &endptr, 10);
     if (score == LONG_MAX || score == LONG_MIN || *endptr)
       return 1;