ucopy: cleanup umoven_peekdata and umovestr_peekdata

* ucopy.c (umoven_peekdata, umovestr_peekdata): Merge aligned
and unaligned tracee address cases.

diff --git a/ucopy.c b/ucopy.c
index b2d5d8110077ceb9e16873d4bf70ee07778da205..c3be41704d59fee2adf08065ef42777078a4054c 100644 (file)
--- a/ucopy.c
+++ b/ucopy.c
@@ -106,44 +106,18 @@ static int
 umoven_peekdata(const int pid, kernel_ulong_t addr, unsigned int len,
                void *laddr)
 {
-       unsigned int n, m, nread;
-       union {
-               long val;
-               char x[sizeof(long)];
-       } u;
-
-       nread = 0;
-       if (addr & (sizeof(long) - 1)) {
-               /* addr not a multiple of sizeof(long) */
-               n = addr & (sizeof(long) - 1);  /* residue */
-               addr &= -sizeof(long);          /* aligned address */
-               errno = 0;
-               u.val = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
-               switch (errno) {
-                       case 0:
-                               break;
-                       case ESRCH: case EINVAL:
-                               /* these could be seen if the process is gone */
-                               return -1;
-                       case EFAULT: case EIO: case EPERM:
-                               /* address space is inaccessible */
-                               return -1;
-                       default:
-                               /* all the rest is strange and should be reported */
-                               perror_msg("umoven: PTRACE_PEEKDATA pid:%d @0x%" PRI_klx,
-                                           pid, addr);
-                               return -1;
-               }
-               m = MIN(sizeof(long) - n, len);
-               memcpy(laddr, &u.x[n], m);
-               addr += sizeof(long);
-               laddr += m;
-               nread += m;
-               len -= m;
-       }
+       unsigned int nread = 0;
+       unsigned int residue = addr & (sizeof(long) - 1);
+
        while (len) {
+               addr &= -sizeof(long);          /* aligned address */
+
                errno = 0;
-               u.val = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
+               union {
+                       long val;
+                       char x[sizeof(long)];
+               } u = { .val = ptrace(PTRACE_PEEKDATA, pid, addr, 0) };
+
                switch (errno) {
                        case 0:
                                break;
@@ -163,8 +137,10 @@ umoven_peekdata(const int pid, kernel_ulong_t addr, unsigned int len,
                                            pid, addr);
                                return -1;
                }
-               m = MIN(sizeof(long), len);
-               memcpy(laddr, u.x, m);
+
+               unsigned int m = MIN(sizeof(long) - residue, len);
+               memcpy(laddr, &u.x[residue], m);
+               residue = 0;
                addr += sizeof(long);
                laddr += m;
                nread += m;
@@ -225,51 +201,18 @@ static int
 umovestr_peekdata(const int pid, kernel_ulong_t addr, unsigned int len,
                  void *laddr)
 {
-       const unsigned long x01010101 = (unsigned long) 0x0101010101010101ULL;
-       const unsigned long x80808080 = (unsigned long) 0x8080808080808080ULL;
-
-       unsigned int n, m, nread;
-       union {
-               unsigned long val;
-               char x[sizeof(long)];
-       } u;
-
-       nread = 0;
-       if (addr & (sizeof(long) - 1)) {
-               /* addr not a multiple of sizeof(long) */
-               n = addr & (sizeof(long) - 1);  /* residue */
-               addr &= -sizeof(long);          /* aligned address */
-               errno = 0;
-               u.val = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
-               switch (errno) {
-                       case 0:
-                               break;
-                       case ESRCH: case EINVAL:
-                               /* these could be seen if the process is gone */
-                               return -1;
-                       case EFAULT: case EIO: case EPERM:
-                               /* address space is inaccessible */
-                               return -1;
-                       default:
-                               /* all the rest is strange and should be reported */
-                               perror_msg("umovestr: PTRACE_PEEKDATA pid:%d @0x%" PRI_klx,
-                                           pid, addr);
-                               return -1;
-               }
-               m = MIN(sizeof(long) - n, len);
-               memcpy(laddr, &u.x[n], m);
-               while (n & (sizeof(long) - 1))
-                       if (u.x[n++] == '\0')
-                               return 1;
-               addr += sizeof(long);
-               laddr += m;
-               nread += m;
-               len -= m;
-       }
+       unsigned int nread = 0;
+       unsigned int residue = addr & (sizeof(long) - 1);
 
        while (len) {
+               addr &= -sizeof(long);          /* aligned address */
+
                errno = 0;
-               u.val = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
+               union {
+                       unsigned long val;
+                       char x[sizeof(long)];
+               } u = { .val = ptrace(PTRACE_PEEKDATA, pid, addr, 0) };
+
                switch (errno) {
                        case 0:
                                break;
@@ -289,11 +232,13 @@ umovestr_peekdata(const int pid, kernel_ulong_t addr, unsigned int len,
                                           pid, addr);
                                return -1;
                }
-               m = MIN(sizeof(long), len);
-               memcpy(laddr, u.x, m);
-               /* "If a NUL char exists in this word" */
-               if ((u.val - x01010101) & ~u.val & x80808080)
-                       return 1;
+
+               unsigned int m = MIN(sizeof(long) - residue, len);
+               memcpy(laddr, &u.x[residue], m);
+               while (residue < sizeof(long))
+                       if (u.x[residue++] == '\0')
+                               return 1;
+               residue = 0;
                addr += sizeof(long);
                laddr += m;
                nread += m;