Come up with startswith function.

New function in system.h that returns true if a string has a given
prefix, false otherwise.  Use it in place of strncmp.

Signed-off-by: Martin Liška <mliska@suse.cz>

6 files changed, 26 insertions, 10 deletions

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index d107e78f..fedf65a4 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,13 @@
+2021-04-19  Martin Liska  <mliska@suse.cz>
+
+        * dwfl_frame.c (dwfl_attach_state): Use startswith.
+        * dwfl_module_getdwarf.c (find_symtab): Likewise.
+        * linux-kernel-modules.c: Likewise.
+        * linux-pid-attach.c (linux_proc_pid_is_stopped): Likewise.
+        (dwfl_linux_proc_attach): Likewise.
+        * relocate.c (resolve_symbol): Likewise.
+        (relocate_section): Likewise.
+
 2021-02-01  Érico Nogueira  <ericonr@disroot.org>
 
         * dwfl_error.c (strerror_r): Only use the GNU version when available.
diff --git a/libdwfl/dwfl_frame.c b/libdwfl/dwfl_frame.c
index 5bbf850e..77e0c5cb 100644
--- a/libdwfl/dwfl_frame.c
+++ b/libdwfl/dwfl_frame.c
@@ -30,6 +30,8 @@
 # include <config.h>
 #endif
 
+#include <system.h>
+
 #include "libdwflP.h"
 #include <unistd.h>
 
@@ -172,7 +174,7 @@ dwfl_attach_state (Dwfl *dwfl, Elf *elf, pid_t pid,
              is called from dwfl_linux_proc_attach with elf == NULL.
              __libdwfl_module_getebl will call __libdwfl_getelf which
              will call the find_elf callback.  */
-          if (strncmp (mod->name, "[vdso: ", 7) == 0
+          if (startswith (mod->name, "[vdso: ")
               || strcmp (strrchr (mod->name, ' ') ?: "",
                          " (deleted)") == 0)
             continue;
diff --git a/libdwfl/dwfl_module_getdwarf.c b/libdwfl/dwfl_module_getdwarf.c
index 2f3dd0dd..6f076057 100644
--- a/libdwfl/dwfl_module_getdwarf.c
+++ b/libdwfl/dwfl_module_getdwarf.c
@@ -1162,7 +1162,7 @@ find_symtab (Dwfl_Module *mod)
   if (sname == NULL)
     goto elferr;
 
-  if (strncmp (sname, ".zdebug", strlen (".zdebug")) == 0)
+  if (startswith (sname, ".zdebug"))
     /* Try to uncompress, but it might already have been, an error
        might just indicate, already uncompressed.  */
     elf_compress_gnu (symstrscn, 0, 0);
@@ -1245,7 +1245,7 @@ find_symtab (Dwfl_Module *mod)
       if (sname == NULL)
         goto elferr;
 
-      if (strncmp (sname, ".zdebug", strlen (".zdebug")) == 0)
+      if (startswith (sname, ".zdebug"))
         /* Try to uncompress, but it might already have been, an error
            might just indicate, already uncompressed.  */
         elf_compress_gnu (aux_strscn, 0, 0);
diff --git a/libdwfl/linux-kernel-modules.c b/libdwfl/linux-kernel-modules.c
index 6edb27f2..c0f8dfa4 100644
--- a/libdwfl/linux-kernel-modules.c
+++ b/libdwfl/linux-kernel-modules.c
@@ -924,7 +924,7 @@ dwfl_linux_kernel_module_section_address
 
           if (!strcmp (secname, ".modinfo")
               || !strcmp (secname, ".data.percpu")
-              || !strncmp (secname, ".exit", 5))
+              || startswith (secname, ".exit"))
             {
               *addr = (Dwarf_Addr) -1l;
               return DWARF_CB_OK;
@@ -935,7 +935,7 @@ dwfl_linux_kernel_module_section_address
              behavior, and this cruft leaks out into the /sys information.
              The file name for ".init*" may actually look like "_init*".  */
 
-          const bool is_init = !strncmp (secname, ".init", 5);
+          const bool is_init = startswith (secname, ".init");
           if (is_init)
             {
               if (asprintf (&sysfile, SECADDRDIRFMT "_%s",
diff --git a/libdwfl/linux-pid-attach.c b/libdwfl/linux-pid-attach.c
index fdf5c9b1..cd534825 100644
--- a/libdwfl/linux-pid-attach.c
+++ b/libdwfl/linux-pid-attach.c
@@ -30,6 +30,8 @@
 # include <config.h>
 #endif
 
+#include <system.h>
+
 #include "libelfP.h"
 #include "libdwflP.h"
 #include <sys/types.h>
@@ -59,7 +61,7 @@ linux_proc_pid_is_stopped (pid_t pid)
 
   have_state = false;
   while (fgets (buffer, sizeof (buffer), procfile) != NULL)
-    if (strncmp (buffer, "State:", 6) == 0)
+    if (startswith (buffer, "State:"))
       {
         have_state = true;
         break;
@@ -407,7 +409,7 @@ dwfl_linux_proc_attach (Dwfl *dwfl, pid_t pid, bool assume_ptrace_stopped)
   char *line = NULL;
   size_t linelen = 0;
   while (getline (&line, &linelen, procfile) >= 0)
-    if (strncmp (line, "Tgid:", 5) == 0)
+    if (startswith (line, "Tgid:"))
       {
         errno = 0;
         char *endptr;
diff --git a/libdwfl/relocate.c b/libdwfl/relocate.c
index 88b5211d..0497bd4f 100644
--- a/libdwfl/relocate.c
+++ b/libdwfl/relocate.c
@@ -30,6 +30,8 @@
 # include <config.h>
 #endif
 
+#include <system.h>
+
 #include "libelfP.h"
 #include "libdwflP.h"
 
@@ -237,7 +239,7 @@ resolve_symbol (Dwfl_Module *referer, struct reloc_symtab_cache *symtab,
             return DWFL_E_LIBELF;
 
           /* If the section is already decompressed, that isn't an error.  */
-          if (strncmp (sname, ".zdebug", strlen (".zdebug")) == 0)
+          if (startswith (sname, ".zdebug"))
             elf_compress_gnu (scn, 0, 0);
 
           if ((shdr->sh_flags & SHF_COMPRESSED) != 0)
@@ -518,7 +520,7 @@ relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr,
        Nothing to do here.  */
     return DWFL_E_NOERROR;
 
-  if (strncmp (tname, ".zdebug", strlen ("zdebug")) == 0)
+  if (startswith (tname, ".zdebug"))
     elf_compress_gnu (tscn, 0, 0);
 
   if ((tshdr->sh_flags & SHF_COMPRESSED) != 0)
@@ -539,7 +541,7 @@ relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr,
   if (sname == NULL)
     return DWFL_E_LIBELF;
 
-  if (strncmp (sname, ".zdebug", strlen ("zdebug")) == 0)
+  if (startswith (sname, ".zdebug"))
     elf_compress_gnu (scn, 0, 0);
 
   if ((shdr->sh_flags & SHF_COMPRESSED) != 0)