Fix: sysconf() unchecked return value

Fix Coverity bug:

CID 1021259 (#1 of 1): Improper use of negative value
(NEGATIVE_RETURNS)5. negative_returns: sysconf(_SC_PAGESIZE) is passed
to a parameter that cannot be negative.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 0a3de32263c068fbffa7c2968218df8dcc14c8a9..1e4bec699b4f454c0d01eef2749f6a7204e5f89d 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -930,7 +930,12 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting)
                long page_size;
 
                page_size = sysconf(_SC_PAGE_SIZE);
-               if (page_size > 0) {
+               if (page_size <= 0) {
+                       if (!page_size) {
+                               errno = EINVAL;
+                       }
+                       PERROR("Error in sysconf(_SC_PAGE_SIZE)");
+               } else {
                        ret = munmap(sock_info->wait_shm_mmap, page_size);
                        if (ret) {
                                ERR("Error unmapping wait shm");
@@ -1112,7 +1117,11 @@ char *get_map_shm(struct sock_info *sock_info)
        char *wait_shm_mmap;
 
        page_size = sysconf(_SC_PAGE_SIZE);
-       if (page_size < 0) {
+       if (page_size <= 0) {
+               if (!page_size) {
+                       errno = EINVAL;
+               }
+               PERROR("Error in sysconf(_SC_PAGE_SIZE)");
                goto error;
        }
 

diff --git a/libringbuffer/ring_buffer_backend.c b/libringbuffer/ring_buffer_backend.c
index b65105f3a92afdfc8eceab615b73708bb045307e..40fae8017aed823401ae85a328be5bb8833a8231 100644 (file)
--- a/libringbuffer/ring_buffer_backend.c
+++ b/libringbuffer/ring_buffer_backend.c
@@ -19,6 +19,7 @@
  */
 
 #define _GNU_SOURCE
+#include <unistd.h>
 #include <urcu/arch.h>
 #include <limits.h>
 
@@ -49,6 +50,7 @@ int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_conf
        unsigned long subbuf_size, mmap_offset = 0;
        unsigned long num_subbuf_alloc;
        unsigned long i;
+       long page_size;
 
        subbuf_size = chanb->subbuf_size;
        num_subbuf_alloc = num_subbuf;
@@ -56,6 +58,11 @@ int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_conf
        if (extra_reader_sb)
                num_subbuf_alloc++;
 
+       page_size = sysconf(_SC_PAGE_SIZE);
+       if (page_size <= 0) {
+               goto page_size_error;
+       }
+
        align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp));
        set_shmp(bufb->array, zalloc_shm(shmobj,
                        sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc));
@@ -64,9 +71,9 @@ int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_conf
 
        /*
         * This is the largest element (the buffer pages) which needs to
-        * be aligned on PAGE_SIZE.
+        * be aligned on page size.
         */
-       align_shm(shmobj, PAGE_SIZE);
+       align_shm(shmobj, page_size);
        set_shmp(bufb->memory_map, zalloc_shm(shmobj,
                        subbuf_size * num_subbuf_alloc));
        if (caa_unlikely(!shmp(handle, bufb->memory_map)))
@@ -122,6 +129,7 @@ free_array:
 memory_map_error:
        /* bufb->array will be freed by shm teardown */
 array_error:
+page_size_error:
        return -ENOMEM;
 }
 
@@ -195,7 +203,7 @@ void channel_backend_reset(struct channel_backend *chanb)
  * @name: channel name
  * @config: client ring buffer configuration
  * @parent: dentry of parent directory, %NULL for root directory
- * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2)
+ * @subbuf_size: size of sub-buffers (> page size, power of 2)
  * @num_subbuf: number of sub-buffers (power of 2)
  * @lttng_ust_shm_handle: shared memory handle
  * @stream_fds: stream file descriptors.
@@ -219,12 +227,17 @@ int channel_backend_init(struct channel_backend *chanb,
        unsigned int i;
        int ret;
        size_t shmsize = 0, num_subbuf_alloc;
+       long page_size;
 
        if (!name)
                return -EPERM;
 
+       page_size = sysconf(_SC_PAGE_SIZE);
+       if (page_size <= 0) {
+               return -ENOMEM;
+       }
        /* Check that the subbuffer size is larger than a page. */
-       if (subbuf_size < PAGE_SIZE)
+       if (subbuf_size < page_size)
                return -EINVAL;
 
        /*
@@ -267,7 +280,7 @@ int channel_backend_init(struct channel_backend *chanb,
        num_subbuf_alloc = num_subbuf + 1;
        shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp));
        shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc;
-       shmsize += offset_align(shmsize, PAGE_SIZE);
+       shmsize += offset_align(shmsize, page_size);
        shmsize += subbuf_size * num_subbuf_alloc;
        shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages));
        shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages) * num_subbuf_alloc;

diff --git a/tests/ust-basic-tracing/ust-basic-tracing.c b/tests/ust-basic-tracing/ust-basic-tracing.c
index cc0fb89b65721fb9fb4329cdae07e2c23b74a604..15368ed73b4a2e7b3ff97fa0d18f0844c4976c84 100644 (file)
--- a/tests/ust-basic-tracing/ust-basic-tracing.c
+++ b/tests/ust-basic-tracing/ust-basic-tracing.c
@@ -647,7 +647,11 @@ int update_futex(int fd, int active)
        int ret;
 
        page_size = sysconf(_SC_PAGE_SIZE);
-       if (page_size < 0) {
+       if (page_size <= 0) {
+               if (!page_size) {
+                       errno = EINVAL;
+               }
+               perror("Error in sysconf(_SC_PAGE_SIZE)");
                goto error;
        }
        wait_shm_mmap = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
@@ -717,6 +721,7 @@ int main(int argc, const char **argv)
        const char *outputpath;
        const char **event_names;
        unsigned int nr_events;
+       long page_size;
 
        if (argc < 2) {
                printf("Usage:\n");
@@ -759,6 +764,15 @@ int main(int argc, const char **argv)
                return -1;
        }
 
+       page_size = sysconf(_SC_PAGE_SIZE);
+       if (page_size <= 0) {
+               if (!page_size) {
+                       errno = EINVAL;
+               }
+               perror("Error in sysconf(_SC_PAGE_SIZE)");
+               return -1;
+       }
+
        if (geteuid() == 0) {
                ret = mkdir(LTTNG_RUNDIR, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
                if (ret && errno != EEXIST) {
@@ -766,7 +780,7 @@ int main(int argc, const char **argv)
                        return -1;
                }
                wait_shm_fd = get_wait_shm(DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH,
-                                       sysconf(_SC_PAGE_SIZE), 1);
+                                       page_size, 1);
                if (wait_shm_fd < 0) {
                        perror("global wait shm error");
                        return -1;
@@ -792,7 +806,7 @@ int main(int argc, const char **argv)
                snprintf(local_apps_wait_shm_path, PATH_MAX,
                         DEFAULT_HOME_APPS_WAIT_SHM_PATH, getuid());
                wait_shm_fd = get_wait_shm(local_apps_wait_shm_path,
-                                       sysconf(_SC_PAGE_SIZE), 0);
+                                       page_size, 0);
                if (wait_shm_fd < 0) {
                        perror("local wait shm error");
                        return -1;

diff --git a/tests/ust-multi-test/ust-multi-test.c b/tests/ust-multi-test/ust-multi-test.c
index c003c5a93f0f00bf033be2a54cccd7015b7996f5..011374395fc4ef5350ff728783f31db8839755e9 100644 (file)
--- a/tests/ust-multi-test/ust-multi-test.c
+++ b/tests/ust-multi-test/ust-multi-test.c
@@ -643,7 +643,11 @@ int update_futex(int fd, int active)
        int ret;
 
        page_size = sysconf(_SC_PAGE_SIZE);
-       if (page_size < 0) {
+       if (page_size <= 0) {
+               if (!page_size) {
+                       errno = EINVAL;
+               }
+               perror("Error in sysconf(_SC_PAGE_SIZE)");
                goto error;
        }
        wait_shm_mmap = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
@@ -706,6 +710,7 @@ int main(int argc, char **argv)
        int ret, wait_shm_fd;
        struct sigaction act;
        mode_t old_umask = 0;
+       long page_size;
 
        set_ulimit();
 
@@ -738,6 +743,15 @@ int main(int argc, char **argv)
                return -1;
        }
 
+       page_size = sysconf(_SC_PAGE_SIZE);
+       if (page_size <= 0) {
+               if (!page_size) {
+                       errno = EINVAL;
+               }
+               perror("Error in sysconf(_SC_PAGE_SIZE)");
+               return -1;
+       }
+
        if (geteuid() == 0) {
                ret = mkdir(LTTNG_RUNDIR, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
                if (ret && errno != EEXIST) {
@@ -745,7 +759,7 @@ int main(int argc, char **argv)
                        return -1;
                }
                wait_shm_fd = get_wait_shm(DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH,
-                                       sysconf(_SC_PAGE_SIZE), 1);
+                                       page_size, 1);
                if (wait_shm_fd < 0) {
                        perror("global wait shm error");
                        return -1;
@@ -771,7 +785,7 @@ int main(int argc, char **argv)
                snprintf(local_apps_wait_shm_path, PATH_MAX,
                         DEFAULT_HOME_APPS_WAIT_SHM_PATH, getuid());
                wait_shm_fd = get_wait_shm(local_apps_wait_shm_path,
-                                       sysconf(_SC_PAGE_SIZE), 0);
+                                       page_size, 0);
                if (wait_shm_fd < 0) {
                        perror("local wait shm error");
                        return -1;