simplify octal esc conversion, minor adjustments

1 files changed, 28 insertions, 37 deletions

diff --git a/src/firejail/mountinfo.c b/src/firejail/mountinfo.c
index 7369ad247..42e160dec 100644
--- a/src/firejail/mountinfo.c
+++ b/src/firejail/mountinfo.c
@@ -33,7 +33,7 @@ static MountData mdata;
 
 // Convert octal escape sequence to decimal value
 static int read_oct(const char *path) {
-        int decimal = 0;
+        int dec = 0;
         int digit, i;
         // there are always exactly three octal digits
         for (i = 1; i < 4; i++) {
@@ -42,29 +42,26 @@ static int read_oct(const char *path) {
                         fprintf(stderr, "Error: cannot read /proc/self/mountinfo\n");
                         exit(1);
                 }
-                decimal = (decimal + digit - '0') * 8;
+                dec = (dec << 3) + (digit - '0');
         }
-        decimal /= 8;
-        return decimal;
+        return dec;
 }
 
 // Restore empty spaces in pathnames extracted from /proc/self/mountinfo
 static void unmangle_path(char *path) {
         char *p = strchr(path, '\\');
-        if (p) {
-                if (read_oct(p) == ' ') {
-                        *p = ' ';
-                        int i = 3;
-                        do {
-                                p++;
-                                if (*(p + i) == '\\' && read_oct(p + i) == ' ') {
-                                        *p = ' ';
-                                        i += 3;
-                                }
-                                else
-                                        *p = *(p + i);
-                        } while (*p);
-                }
+        if (p && read_oct(p) == ' ') {
+                *p = ' ';
+                int i = 3;
+                do {
+                        p++;
+                        if (*(p + i) == '\\' && read_oct(p + i) == ' ') {
+                                *p = ' ';
+                                i += 3;
+                        }
+                        else
+                                *p = *(p + i);
+                } while (*p);
         }
 }
 
@@ -136,7 +133,6 @@ MountData *get_last_mount(void) {
         // open /proc/self/mountinfo
         FILE *fp = fopen("/proc/self/mountinfo", "re");
         if (!fp) {
-                perror("fopen");
                 fprintf(stderr, "Error: cannot read /proc/self/mountinfo\n");
                 exit(1);
         }
@@ -167,31 +163,24 @@ int get_mount_id(const char *path) {
         if (asprintf(&fdinfo, "/proc/self/fdinfo/%d", fd) == -1)
                 errExit("asprintf");
         FILE *fp = fopen(fdinfo, "re");
-        if (!fp) {
-                perror("fopen");
-                fprintf(stderr, "Error: cannot open %s\n", fdinfo);
-                exit(1);
-        }
+        free(fdinfo);
+        if (!fp)
+                goto errexit;
 
         // read the file
         char buf[MAX_BUF];
-        if (fgets(buf, MAX_BUF, fp) == NULL) {
-                fprintf(stderr, "Error: cannot read %s\n", fdinfo);
-                exit(1);
-        }
+        if (fgets(buf, MAX_BUF, fp) == NULL)
+                goto errexit;
         do {
                 if (strncmp(buf, "mnt_id:", 7) == 0) {
                         char *ptr = buf + 7;
                         while (*ptr != '\0' && (*ptr == ' ' || *ptr == '\t')) {
                                 ptr++;
                         }
-                        if (*ptr == '\0') {
-                                fprintf(stderr, "Error: cannot read %s\n", fdinfo);
-                                exit(1);
-                        }
+                        if (*ptr == '\0')
+                                goto errexit;
                         fclose(fp);
                         close(fd);
-                        free(fdinfo);
                         return atoi(ptr);
                 }
         } while (fgets(buf, MAX_BUF, fp));
@@ -199,8 +188,11 @@ int get_mount_id(const char *path) {
         // fallback, kernels older than 3.15 don't expose the mount id in this place
         fclose(fp);
         close(fd);
-        free(fdinfo);
         return -2;
+
+errexit:
+        fprintf(stderr, "Error: cannot read proc file\n");
+        exit(1);
 }
 
 // Check /proc/self/mountinfo if path contains any mounts points.
@@ -211,7 +203,6 @@ char **build_mount_array(const int mount_id, const char *path) {
         // open /proc/self/mountinfo
         FILE *fp = fopen("/proc/self/mountinfo", "re");
         if (!fp) {
-                perror("fopen");
                 fprintf(stderr, "Error: cannot read /proc/self/mountinfo\n");
                 exit(1);
         }
@@ -245,8 +236,8 @@ char **build_mount_array(const int mount_id, const char *path) {
                                     strstr(mntp.fsname, "firejail.ro.file"))
                                             break;
 
-                                *rv = strdup(path);
-                                if (*rv == NULL)
+                                rv[0] = strdup(path);
+                                if (rv[0] == NULL)
                                         errExit("strdup");
                                 cnt++;
                                 found = 1;